Scientifica
Volume 2018 (2018), Article ID 4596450, 17 pages
https://doi.org/10.1155/2018/4596450

Review Article

Vangueria madagascariensis Fruit Tree: Nutritional, Phytochemical, Pharmacological, and Primary Health Care Applications as Herbal Medicine

Alfred Maroyi

Medicinal Plants and Economic Development (MPED) Research Centre, Department of Botany, University of Fort Hare, Private Bag X1314, Alice 5700, South Africa

Correspondence should be addressed to Alfred Maroyi; amaroyi@ufh.ac.za

Received 17 July 2018; Accepted 25 September 2018; Published 1 November 2018

Academic Editor: Marie-Aleth Lacaille-Dubois

Copyright © 2018 Alfred Maroyi. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract.

Vangueria madagascariensis J. F. Gmel. is a plant species regarded as an important fruit tree and medicinal plant in sub-Saharan Africa. This study critically reviewed the nutritional value, phytochemistry, medicinal uses, and pharmacological properties of V. madagascariensis. Relevant information on food and medicinal uses of the species was collected from electronic databases such as ISI Web of Knowledge, ProQuest, ScienceDirect, OATD, Scopus, OpenThesis, PubMed, and Google Scholar, and preelectronic literatures were obtained from the university library covering the period 1966 to 2018. Literature studies revealed that V. madagascariensis has been integrated into farming systems as a fruit tree to support income and nutritional security of households in the region. Vangueria madagascariensis is used as a herbal medicine against diabetes, gastrointestinal problems, malaria, pain, parasitic worms, and skin diseases. Phytochemical compounds identified from the species include alcohols, aldehydes, esters, furanoids, ketones, and terpenoids. Pharmacological studies revealed that V. madagascariensis extracts have antibacterial, anticonvulsant, antidiabetic, antifungal, anti-inﬂammatory, antioxidant, cytotoxicity, antimalarial, and antiplasmodial properties. Vangueria madagascariensis should be subjected to detailed nutritional, pharmacological, and toxicological evaluations aimed at correlating the traditional uses of the species and the scientific evidence as well as establishing the efficacy, clinical relevance, safety, and mechanisms of action of the plant extracts and compounds.

1. Introduction

Over the last three decades, there has been renewed interest in the phytochemical properties of Vangueria madagascariensis J. F. Gmel. (Figure 1), a plant species with edible fruits and used as a herbal medicine throughout its distributional range. Vangueria madagascariensis belongs to the bedstraw or family Rubiaceae, which is regarded as one of the largest plant groups characterized by about 637 genera and 13000 taxa [1, 2]. Vangueria madagascariensis is a type of species of the genus Vangueria Juss., which formed a strongly supported group or clade including V. esculenta S. Moore, V. infausta Burch., and V. proschii Briq. based on the results of chloroplast markers trnT-F and rps16 and nuclear ITS [1]. All these four species are characterized by calyx lobes that are narrow, oblong, and triangular in shape [1]. Vangueria genus is made up of about 50 small trees, shrubs, and geofrutices species distributed in sub-Saharan Africa with V. madagascariensis also occurring in Madagascar, Mauritius, Réunion, and Seychelles [1, 3]. East Africa, particularly Kenya and Tanzania, is regarded as the centre of diversity of this genus, which is regarded as rare in West Africa [1]. The genus name Vangueria is based on the local Malagasy name “voa vanguer” of V. madagascariensis [4–6]. The specific name “madagascariensis” means “of Madagascar” in reference to Madagascar where the specimen type was collected from the species described in 1791 by Johann Friedrich Gmelin (1748–1804), a German naturalist and botanist. English common names of V. madagascariensis include common wild medlar, Spanish-tamarind, tamarind-of-the-Indies, voa vanga, and wild medlar [7–9]. The synonyms of the species include V. acutiloba Robyns, V. edulis Vahl., V. floribunda Robyns, V. madagascariensis subsp. madagascariensis, V. madagascariensis var. madagascariensis, V. robynsii Tennant, V. venosa Hochst. ex A. Rich., Vavanga chinensis Rohr, and Vavanga edulis Vahl [3].

Figure 1: Vangueria madagascariensis: a branch showing leaves, flowers, and fruits (photo: Guiseppe Mazza).

Vangueria madagascariensis is a multistemmed deciduous shrub or tree growing up to 15 metres in height. The species is native to Réunion, Tanzania, Democratic Republic of Congo, South Sudan, Angola, Cameroon, Ghana, Benin, Central African Republic, Ethiopia, Eritrea, Madagascar, Mauritius, Mozambique, Nigeria, South Africa, Sudan, Swaziland, Togo, Uganda, Seychelles, and Kenya [3] (Figure 2). The species has been recorded on rocky, sandy red clay, or sandy clay soils in riverine bushlands, evergreen forests, bushed grasslands, rocky outcrops, and termite mounds at an altitude ranging from 0 to 2400 metres above the sea level [3]. Vangueria madagascariensis is cultivated in China, Congo, Cuba, India, northern Australia, Singapore, and Trinidad [8–12]. Considering the existing literature focusing on utilization of V. madagascariensis throughout its distributional range, it is evident that different plant parts are used as both food and herbal medicines as these plant parts have several phytochemical compounds and micronutrients required for human nutrition and health [9, 13–17]. Previous research showed that the medicinal and nutritional properties of edible fruits collected from the wild enable local communities to use such plant resources as traditional remedies, at the same time broadening their nutritional options, micronutrients, diet, and vitamins [6, 18, 19]. Vangueria madagascariensis is regarded as a popular fruit tree and medicinal plant, and the plant species has positive effects on human health and well-being [9, 13–17] which are beyond the provisions of basic nutritional requirements. There is no universally accepted definition of functional food and nutraceuticals, but Hailu et al. [20], Shahidi [21], and Wang and Li [22] argued that functional food and nutraceuticals are natural foods that beneficially affect one or several body functions apart from nutritional effects, influencing both the health and well-being of the consumer. The value of pharmaceutical drugs derived from plants, other natural health products, nutraceuticals, and functional foods are being promoted throughout the world as an alternative strategy for disease risk reduction and reduction in health care costs [21]. It is within this background that the nutritional value, chemical properties, medicinal uses, and biological activities of V. madagascariensis were evaluated.

Figure 2: Natural distribution of Vangueria madagascariensis.

2. Food Uses

The fruits of V. madagascariensis which are globose, smooth and shiny, and yellowish brown in colour when ripe are edible and highly sought after throughout the distributional range of the species. Although the fruits are mainly collected from the wild, but in clearing land for agricultural purposes, some farmers leave these trees as future sources of fruits. Teklehaimanot [23] identified V. madagascariensis, Strychnos cocculoides Baker, Balanites aegyptiaca (L.) Delile, Vitex doniana Sweet, Berchemia discolor (Klotzsch) Hemsl., Sclerocarya birrea (A. Rich.) Hochst., Borassus aethiopum Mart., Carissa spinarum L., Cordeauxia edulis Hemsl., and Vitellaria paradoxa C. F. Gaertn. as priority indigenous fruit tree species with domestication potential in Ethiopia, Kenya, South Sudan, Sudan, Tanzania, and Uganda. Therefore, V. madagascariensis has been integrated into rural agricultural farming systems in sub-Saharan countries as a strategy to improve food and income security of households in the region. Based on the popularity of its fruits, V. madagascariensis was also introduced in home gardens in Congo, Cuba, India, and the West Indies [8–10]. The fruits are marketed in Cuba, Ethiopia, Kenya, Madagascar, Tanzania, and Uganda [8–10, 24, 25].

The fruit pulp of V. madagascariensis has a sweet, pleasant chocolate-like flavour when eaten raw and a somewhat astringent and acidic taste like a blend of apple (Malus pumila Miller) and tamarind (Tamarindus indica L.) [8, 26]. The pulp is also stewed, roasted, added to mealie meal porridge and other food to add flavour, and made into juice, jellies, jam, and puddings [26–29]. In Ethiopia, fruits of V. madagascariensis are an important food resource especially during droughts and in times of food shortages [30]. The pulp is a good source of both macrominerals and trace elements such as potassium, zinc, calcium, magnesium, chromium, phosphorus, copper, manganese, and iron (Table 1). The nutritional contribution of the pulp is comparable to other well-known fruits with commercial potential such as Mangifera indica L. and Ziziphus mauritiana Lam (Table 1). Mangifera indica and Ziziphus mauritiana are among the top five important fruit species in the dryland agricultural farming systems in tropical Africa that contribute to household incomes, nutritional needs, and food security [38]. Several amino acids and fatty acids (Table 2) have been identiﬁed from the fruit pulp of V. madagascariensis, and these include the essential amino acids such as lysine, threonine, histidine, leucine, phenylalanine, valine, isoleucine, and methionine [39, 44]. Research by Mariod et al. [15] revealed that the contribution of conditionally essential amino acids such as tyrosine, arginine, glycine, and cysteine and nonessential amino acids such as glutamic acid, aspartic acid, and serine was close to 50% (5.9 g out of 14.2 g/100 g) of the total amino acids identified from the species (Table 2). The amino acid and fatty acid constituents and other physicochemical properties of V. madagascariensis make the species a valuable source of these nutrients when compared with the nutritional value of Mangifera indica and Ziziphus mauritiana and the FAO/WHO/UNU dietary reference intakes or RDA required to meet essential nutrients for a healthy person (Tables 1 and 2). Pino et al. [9] identified sixty volatile constituents from the fruit pulp of V. madagascariensis (Table 3). The major phytochemical compounds identified include alcohols, aldehydes, esters, furanoids, ketones, and terpenoids (Table 3). Pino et al. [9] argued that the acidic and pungent taste associated with the fruit pulp of V. madagascariensis can be explained by the higher amounts of fatty acids as shown in Table 2.

Table 1: Nutritional composition of the fruit pulp of V. madagascariensis compared with nutritional values of Mangifera indica and Ziziphus mauritiana and the recommended dietary allowance (RDA).

Caloric and nutritional composition
Value
Ziziphus mauritiana
Mangifera indica
Recommended dietary allowance (RDA)

Ascorbic acid (mg/100 g)
4.7
15.0–43.8
16.0–46.5
100–120

Calcium (mg/100 g)
25
160–254
14.0–30.6
1000–1300

Carbohydrates (%)
28
79.5–83.2
16.9–27.3
45–65

Copper (mg/100 g)
0.5 ± 0.2
0.7–1.5
0.1
1–3

Chromium (mg/100 g)
0.2 ± 0.1
0.1
0.01–0.02
0.02–0.2

Energy value (kJ/100 g)
498
1516–1575
74
2200

Fibre (%)
4.7
4.9–7.3
1.1–4.8
25–38

Iron (mg/100 g)
1.1–5.2
2.1–4.3
1.3–8.4
8–15

Lipid (%)
0.1
—
0.1
300

Magnesium (mg/100 g)
39
83–150
1.5–7.5
310–320

Manganese (mg/100 g)
2.4 ± 1.1
0.7–1.6
6.2–7.8
1–5

Niacin (mg/100 g)
0.61
0-7–0.9
0.6
40–70

Phosphorus (mg/100 g)
36.6
87–148
16
1250

Potassium (mg/100 g)
521
1865–2441
10.2–205
4700

Protein (%)
1.4
7.9–8.7
0.6
34

Riboflavin (mg/100 g)
0.04
0.02
0.6
3–10

Sodium (mg/100 g)
28
185–223
26–91.1
2300

Thiamine (mg/100 g)
0.05
0.03
0.05
6.1

Total flavonoid content (mg RE/g fresh weight)
8.00 to 8.20
8.4–22.0

1000

Total phenolic content (mg GAE/g dry weight)
37.00 to 61.22
172.1–309.5
652.6
2500

Total proanthocyanidins (mg CE/g fresh weight)
134.57 to 159.50
—
7.9
1000

Zinc (mg/100 g)
0.4 ± 0.2
0.6–0.9
0.04
8–11

Sources: Ramalingum and Mahomoodally [14]; Nigam et al. [31]; Kipkemboi [32]; Nyanga et al. [33]; Pareek et al. [34]; Ara et al. [35]; da Silva et al. [36]; Sajib et al. [37].

Table 2: Fatty acids and amino acid composition of fruit pulp of V. madagascariensis compared with nutritional values of Mangifera indica and Ziziphus mauritiana and the recommended dietary allowance (RDA).

Chemical composition
Value
Ziziphus mauritiana
Mangifera indica
Recommended dietary allowance (RDA)

Amino acids (g/100 g)

Arginine
1.1 ± 0.6
0.7
0.02
—

Aspartic acid
1.5 ± 0.7
1.3
0.04
—

Glutamic acid
1.9 ± 0.6
1.3
0.06
—

Glycine
0.8 ± 0.1
0.3
0.02
—

Histidine
0.7 ± 0.6
0.1
0.01
10

Isoleucine
0.82 ± 0.5
0.3
0.02
20

Leucine
1.6 ± 0.6
0.5
0.03
39

Lysine
0.8 ± 0.4
0.3
0.04
30

Methionine + cysteine
0.21 ± 0.1
0.1
0.01
15

Phenylalanine + tyrosine
1.3 ± 0.6
0.3
0.02
25

Serine
0.7 ± 0.4
0.3
0.02
—

Threonine
0.74 ± 0.4
0.3
0.02
15

Valine
1.0 ± 0.5
0.4
0.03
26

Fatty acids (mg/kg)

Acetic acid
0.12
—
—
—

Butyric acid
0.12
—
—
—

Decanoic acid
0.08
—
—
—

Dodecanoic acid
0.30
0.05
0.02–0.5
—

Heptanoic acid
1.70
—
0.04–0.2
—

Hexadecanoic acid
5.19
4.0
2.2–14.6
—

Hexanoic acid
1.80
—
—
—

Octanoic acid
1.95
—
—
—

Octadecanoic acid
0.69
2.2
1.6–3.4
—

Pentadecanoic acid
0.61
—
0.02–0.04
—

Pentanoic acid
0.01
—
—
—

Undecanoic acid
0.04
—
—
—

Tetradecanoic acid
4.50
0.1
0.1–1.1
—

(Z)-9-Octadecenoic acid
0.06
—
—
—

Sources: Pino et al. [9]; Mariod et al. [15]; FAO/WHO/UNU [38]; Institute of Medicine [39]; Sena et al. [40]; Bally [41]; Vilela et al. [42]; Deshpande et al. [43].

Table 3: Volatile phytochemical compounds identified from V. madagascariensis fruits.

Phytochemical composition
Values (mg/kg)

Alcohol

α-Terpineol
0.10

2-Methyl-3-buten-2-ol
1.07

Benzyl alcohol
0.25

Ethanol
0.08

2-Butanol
0.54

Isoamyl alcohol
1.38

2-Methylbutanol
0.24

3-Methyl-2-butenol
0.12

Octanol
0.51

Furfuryl alcohol
1.15

(Z)-3-Hexenol
0.06

Hexanol
2.40

Aldehyde

2-Methylbutanal
0.43

2-Furfural
11.93

3-Furfural
2.43

2-Phenylacetaldehyde
2.12

Acetaldehyde
<0.01

Benzaldehyde
2.12

(E)-2-Octenal
3.84

(E,E)-2,6-Hexadienal
0.08

(E)-4-Undecenal
0.51

(E)-4-Nonenal
0.17

(E)-4-Decenal
0.09

(E,E)-4,4-Heptadienal
0.28

(E,Z)-4,4-Heptadienal
0.29

Heptanal
0.83

Hexanal
0.82

Isovaleraldehyde
0.44

Ester

Methyl benzoate
0.56

Methyl 2-phenylacetate
0.34

2-Phenylethyl acetate
0.54

Methyl hexanoate
2.14

Methyl (Z)-3-hexenoate
<0.01

Methyl (E)-2-hexenoate
<0.01

Methyl octanoate
1.98

Methyl decanoate
0.05

Methyl butyrate
0.08

Methyl (E)-cinnamate
0.04

Methyl 9,12,15-octadecatrienoate
0.11

Methyl (Z)-9-hexadecenoate
0.51

Methyl hexadecanoate
0.39

Methyl octadecanoate
0.10

Methyl pentanoate
0.10

Methyl salicylate
0.08

Methyl tetradecanoate
<0.01

Monoterpene

Terpinolene
0.09

p-Cymene
0.01

Limonene
2.48

Furan

2-Propylfuran
<0.01

5-Methylfurfural
0.04

Indole

1H-indole
0.04

Ketone

2-Heptanone
0.28

2-Pentanone
0.41

3-Penten-2-one
0.10

Acetoin
0.04

5-Butyldihydro-2(3H)-furanone
<0.01

5-Ethyldihydro-2(3H)-furanone
1.95

δ-Octalactone
0.12

γ-Dodecalactone
0.04

Norisoprenoids

4-Ketoisophorone
0.02

Source: Pino et al. [9].

3. Medicinal Uses of Vangueria madagascariensis

The seeds, bark, leaves, fruits, roots, and stem bark of V. madagascariensis are utilized in monotherapeutic or multitherapeutic applications in Eritrea, Kenya, Madagascar, Mauritius, Sudan, and Tanzania (Table 4). Bark, fruit, leaf, and root maceration of V. madagascariensis is taken by mouth for diabetes in Madagascar [47], Mauritius [14, 48], and Sudan [49, 50]. Bark, leaf, root bark, and stem bark infusion of V. madagascariensis is taken by mouth for bloody diarrhoea in Tanzania [45], dysentery in Mauritius [47], and stomach problems in Kenya [58]. Root bark and root infusion of V. madagascariensis is taken by mouth for intestinal worms in Eritrea [52] and Tanzania [8, 45]. Bark, root bark, and stem bark maceration of V. madagascariensis is taken by mouth for malaria in Kenya [53–57] and Tanzania [8, 45, 51]. In Tanzania, the leaf, root, root bark, and stem bark maceration of V. madagascariensis is taken by mouth for abdominal pains, asthma, convulsions, gonorrhoea, hepatitis, hernia, and oedema [45, 51]. Fruit decoction of V. madagascariensis is taken by mouth for back pain and mouth infections in Kenya [46, 58], while root decoction is taken orally as a purgative in Eritrea [52]. In Sudan, the fruit and seed decoction of V. madagascariensis is taken orally as a remedy for hypertension, kidney problems, and tumour [50, 59], while bark and leaf decoction is taken orally for palpitations and nausea in Mauritius [47]. Multitherapeutic applications of V. madagascariensis involve mixing leaves of the species with leaves of Jatropha curcas L., Azadirachta indica A. Juss., and Ipomoea pes-caprae (L.) R. Br. as a herbal medicine for abscesses, carbuncle, and scurf in Mauritius [14]. In Mauritius, the leaf decoction of V. madagascariensis is mixed with the leaves of Jatropha curcas, Toddalia asiatica (L.) Lam., and Sporobolus africanus (Poir.) Robyns & Tournay as a mouthwash [48].

Table 4: Medicinal applications of Vangueria madagascariensis.

Medicinal use
Parts of the plant used
Country
References

Abdominal pains
Roots
Tanzania
[45]

Abscesses, carbuncle, and scurf
Leaf decoction mixed with leaves of Jatropha curcas L., Azadirachta indica A. Juss., and Ipomoea pes-caprae (L.) R. Br.
Mauritius
[14]

Asthma
Leaves
Tanzania
[45]

Back pain
Fruits
Kenya
[46]

Bloody diarrhoea
Stem bark
Tanzania
[45]

Palpitations
Bark and leaves
Mauritius
[47]

Convulsions
Stem bark
Tanzania
[45]

Diabetes
Bark, leaves, fruits, and roots
Madagascar, Mauritius, and Sudan
[14, 47–50]

Dysentery
Bark and leaves
Mauritius
[47]

Gonorrhoea
Stem bark
Tanzania
[45]

Hepatitis
Roots and root bark
Tanzania
[45, 51]

Hernia
Stem bark
Tanzania
[45]

Hypertension
Fruits
Sudan
[50]

Intestinal worms
Roots and root bark
Eritrea and Tanzania
[8, 51, 52]

Kidney problems
Fruits
Sudan
[50]

Malaria
Bark, roots, and stem bark
Kenya and Tanzania
[8, 45, 51, 53–57]

Mouth infections
Roots
Kenya
[58]

Mouthwash
Leaf decoction taken orally mixed with leaves of Jatropha curcas, Toddalia asiatica (L.) Lam., and Sporobolus africanus (Poir.) Robyns & Tournay
Mauritius
[48]

Nausea
Bark and leaves
Mauritius
[47]

Oedema
Stem bark
Tanzania
[45]

Purgative
Roots
Eritrea
[52]

Stomach problems
Roots
Kenya
[58]

Tumour
Seeds
Sudan
[59]

4. Phytochemistry and Pharmacological Properties of Vangueria madagascariensis

Phytochemical screening of the bark, fruits, leaves, kernel oil, seeds, stems, and stem bark has shown the presence of fibre, carbohydrates, proteins, and several classes of phytochemicals such as volatile and nonvolatile metabolites (Table 5), and chemical structures of representative phytochemical compounds are shown in Figure 3. The majority of the phytochemicals were identified using high-performance liquid chromatography (HPLC-DAD) with diode array detection (DAD), mass spectrometry (MS), gas chromatography-mass spectrometry (GC/MS), nuclear magnetic resonance (NMR) spectroscopy, and gas chromatography (GC) (Table 5). Each fruit of V. madagascariensis has 4 to 5 seeds, and the seed kernel contains considerable amount of oil which is higher than that of conventional oil seeds such as groundnut (Arachis hypogaea L.), cottonseed (Gossypium hirsutum L.), and sunflower (Helianthus annuus L.) [62]. Some of the phytochemical compounds such as flavonoids identified from V. madagascariensis are known to have antiallergic, anti-inflammatory, antimicrobial, antiproliferative, antioxidant, enzyme inhibition, and oestrogenic activities, synergism with antibiotics, and suppression of bacterial virulence [63–66]. Research by Prochazkova et al. [65] revealed that the antioxidant activities of flavonoids involve quenching free radical elements, metal chelation, suppression of enzymes involved in free radical scavenging, and stimulation of enzymes that activate antioxidant activities. Research has also revealed that food resources characterized by high levels of flavonoids and related phenolic compounds may reduce the risk of cardiovascular diseases [67]. Pereira et al. [63] argued that the structural figure of phenolic compounds has the potential to interact with several proteins; mainly, they have a hydrophobic benzenoid ring and hydrogen-binding properties which enhance their capacity to be antioxidants by inhibiting several enzymes that catalyze radical generation, including xanthine oxidase, cytochrome P450 isoforms, cyclooxygenase, and lipoxygenase enzymes. The different parts of V. madagascariensis are associated with several fatty acids [16, 60, 61], and these compounds are known to have a wide range of physiological effects such as cardiovascular function, immune system regulation, neuronal development, regulation of plasma lipid levels, insulin regulation, and visual function [68]. Several studies done elsewhere demonstrated the importance of dietary intake of fatty acids as they lead to reduced blood pressure, they lower the risk of heart attack and arteriosclerosis risks, and these compounds are associated with antimicrobial properties and synthetic accessibilities [69–71]. Desbois and Smith [71] argued that the antimicrobial properties of fatty acids are based on their ability to disturb and distort the oxidative phosphorylation process and the electron transport chain process, thereby disturbing the cellular energy production, leading to reduction of enzymatic activity, reduced nutrient uptake, and production of toxic peroxidation. The phytochemicals detected in various parts of V. madagascariensis may be used to justify some of the medicinal uses of this species recorded in Table 4 and also documented antibacterial [13, 60, 72], anticonvulsant [60], antidiabetic [13, 73], antifungal [60, 74], anti-inﬂammatory [60], antioxidant [13, 17], cytotoxicity [17], antimalarial, and antiplasmodial [55, 56] activities.

Table 5: Nutritional and phytochemical composition of Vangueria madagascariensis.

Compound
Value
Method of compound analysis
Plant part
References

Carbohydrates (%)
14.6

Seeds
[16]

Fibre (%)
14.0 ± 0.2

Seeds
[16]

Moisture (%)
6.4 ± 0.1

Seeds
[16]

Protein (%)
22.2 ± 0.3

Seeds
[16]

Total flavonoid content (mg RE/g fresh weight)
6.7–9.0
—
Leaves, fruits, and seeds
[13]

Total phenolic content (mg GAE/g fresh weight)
35.0–122.2
—
Leaves, fruits, and seeds
[13]

Total proanthocyanidins (mg CE/g fresh weight)
42.5–185.7
—
Leaves, fruits, and seeds
[13]

Vitamin E

α-Tocopherol (mg/100 g)
28.5–31.6
GC/MS and HPLC
Kernel oil
[16]

β-Tocopherol (mg/100 g)
63.8–65.7
GC/MS and HPLC
Kernel oil
[16]

γ-Tocopherol (mg/100 g)
4.7–5.1
GC/MS and HPLC
Kernel oil
[16]

δ-Tocopherol (mg/100 g)
8.4–10.5
GC/MS and HPLC
Kernel oil
[16]

Alcohol

Cetyl alcohol
—
NMR
Leaves and stem bark
[60]

Cyclitol

Ethyl-1-O-glucosyl-4-O-(E) caffeoyl quinate
—
NMR
Leaves and stem bark
[60]

Flavonoid

Kaempferol-3-O-rhamnoside-7-O-rutinoside
—
NMR
Leaves and stem bark
[60]

Coumarin

Esculetin
—
NMR
Leaves and stem bark
[60]

Phenolics

Chlorogenic acid (mg/100 g)
1.0–1.2
HPLC-DAD and MS
Leaves and seeds
[17]

Ferulic acid (mg/100 g)
0.03–0.06
HPLC-DAD and MS
Leaves and seeds
[17]

Gallic acid (mg/100 g)
0.004–0.06
HPLC-DAD and MS
Bark, leaves, and seeds
[17]

Hydroxybenzoic acid (mg/100 g)
0.03–0.05
HPLC-DAD and MS
Leaves and seeds
[17]

p-Coumaric acid (mg/100 g)
0.005–0.03
GC, HPLC-DAD, MS, and NMR
Leaves, seeds, stems, and stem bark
[17, 60]

Protocatechuic acid
—
NMR
Leaves and stem bark
[60]

Scopoletin
—
NMR
Leaves and stem bark
[60]

Syringic acid (mg/100 g)
0.007–0.21
HPLC-DAD and MS
Bark, leaves, and seeds
[17]

Vanillic acid
—
NMR
Leaves and stem bark
[60]

Vanillin (mg/100 g)
0.02–0.05
HPLC-DAD and MS
Bark, leaves, and seeds
[17]

Monomethyl ester

4,4-Dimethyl pimelate (%)
0.1
GC/MS
Leaves and stems
[60]

Methyl margarate (%)
1.1
GC/MS
Leaves and stems
[60]

Methyl myristate (%)
3.1
GC/MS
Leaves and stems
[60]

Methyl palmitate (%)
44.7
GC/MS
Leaves and stems
[60]

Methyl stearate (%)
10.5
GC/MS
Leaves and stems
[60]

Pentadecyl cyclohexanecarboxylate (%)
2.2
GC/MS
Leaves and stems
[60]

Fatty acids

9-Hexadecenoic acid (%)
0.4
GC/MS
Leaves and stems
[60]

9-Dodecenoic acid (%)
0.2
GC/MS
Leaves and stems
[60]

8,11-Octadecadienoic acid (%)
8.9
GC/MS
Leaves and stems
[60]

9,12,15-Octadecatrienoic acid (%)
12.1
GC/MS
Leaves and stems
[60]

11-Octadecenoic acid (%)
0.1
GC/MS
Leaves and stems
[60]

Arachidic acid (%)
2.2–5.9
GC, GC/MS, and HPLC
Kernel oil and leaves
[16, 61]

Capric acid (%)
3.7–4.1
GC, GC/MS, and HPLC
Kernel oil
[16]

Docosanoic acid (%)
2.7
GC/MS
Leaves and stems
[60]

Dodecanoic acid (%)
0.2
GC/MS
Leaves and stems
[60]

Eicosanoic acid (%)
6.0
GC/MS
Leaves and stems
[60]

Erucic acid (%)
0.2–0.7
GC/MS and HPLC
Kernel oil
[16]

Heneicosanoic acid (%)
0.9
GC/MS
Leaves and stems
[60]

Hexadecadienoic acid (%)
0.5
GC
Leaves
[61]

Hexadecatrienoic acid (%)
1.3
GC
Leaves
[61]

Linolenic acid (%)
0.4–43.7
GC and GC/MS
Leaves and stems
[60, 61]

Linoleic acid (%)
0.3–63.4
GC, GC/MS, and HPLC
Kernel oil, leaves, and stems
[16, 60, 61]

α-Linoleic acid (%)
0.4–0.7
GC/MS, HPLC, and GC
Kernel oil
[16]

Myristic acid (%)
0.9–2.1
GC/MS, HPLC, and GC
Kernel oil and leaves
[16, 61]

Nonanedioic acid (%)
0.1
GC/MS
Leaves and stems
[60]

Nonadecanoic acid (%)
0.6
GC/MS
Leaves and stems
[60]

Oleic acid (%)
3.8–10.5
GC, GC/MS, and HPLC
Kernel oil and leaves
[16, 61]

Palmitic acid (%)
9.7–20.9
GC, GC/MS, HPLC, and NMR
Kernel oil, leaves, and stem bark
[16, 60, 61]

Palmitoleic acid (%)
1.0
GC
Leaves
[61]

Pentadecanoic acid (%)
0.1
GC/MS
Leaves and stems
[60]

Pentacosanoic acid (%)
0.2
GC/MS
Leaves and stems
[60]

Stearic acid (%)
5.1–9.4
GC, GC/MS, and HPLC
Kernel oil and leaves
[16, 61]

Tetracosanoic acid (%)
1.6
GC/MS
Leaves and stems
[60]

Tricosanoic acid (%)
1.0
GC/MS
Leaves and stems
[60]

trans-Hexadecenoic acid (%)
1.7
GC
Leaves
[61]

Sterols

Campesterol (%)
22.7
GC/MS
Kernel oil
[16]

β-Sitosterol (%)
45.2
GC/MS and NMR
Kernel oil, leaves, and stem bark
[16, 60]

β-Sitosterol acetate
—
NMR
Leaves and stem bark
[60]

β-Sitosterol-5-β-O-glucosapranoside
—
NMR
Leaves and stem bark
[60]

∆-5-avenasterol (%)
1.4
GC/MS
Kernel oil
[16]

Lanosterin (%)
5.6
GC/MS
Kernel oil
[16]

Cycloartenol (%)
4.3
GC/MS
Kernel oil
[16]

(+)-24-Dammarene-3β-20S-diol (%)
0.7
GC/MS
Kernel oil
[16]

Stigmasterol (%)
20.1
GC/MS and NMR
Kernel oil, leaves, and stem bark
[16, 60]

Figure 3: Phytochemical structures of representative phytochemical compounds isolated from Vangueria madagascariensis.

4.1. Antibacterial Activities

Bishay et al. [60] assessed antibacterial properties of leaf and bark ethyl acetate, chloroform, and n-hexane extracts of V. madagascariensis against Pseudomonas aeruginosa, Bacillus cereus, Escherichia coli, Klebsiella pneumoniae, Micrococcus luteus, and Staphylococcus aureus using the modified diffusion method with dimethylformamide (DMF) and gentamicin (5 µg/ml) as negative and positive controls, respectively (Table 6). The extracts showed activities with the zone of inhibition stretching from 4 mm to 18 mm which was comparable to the zone of inhibition of 10 mm to 14 mm demonstrated by gentamicin, the control. The minimum inhibitory concentration (MIC) values ranged from 6.3 µg/ml to 75 µg/ml [60]. Ramalingum and Mahomoodally [13] evaluated antibacterial properties of methanol and crude fruit, leaf, and seed extracts of V. madagascariensis making use of the disc diffusion and microtitre dilution broth method against Escherichia coli and Staphylococcus aureus with streptomycin sulphate and gentamicin sulphate as positive controls (Table 6). The crude ripe and unripe fruit extracts and methanol leaf and seed extracts exhibited some antibacterial properties with the zone of inhibition ranging 8.3 mm to 12.7 mm and MIC values ranging from 6.3 mg/mL to 25.0 mg/mL [13]. Mahomoodally and Dilmohamed [72] evaluated antibacterial activities of fruit and leaf extracts of V. madagascariensis against Klebsiella spp., Acinetobacter spp., Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus, Proteus spp., Streptococcus spp. and methicillin-resistant Staphylococcus aureus (MRSA), and Escherichia coli using the microdilution broth method with chloramphenicol and gentamicin as positive controls (Table 6). The extracts demonstrated antibacterial properties with MIC values ranging from <0.1 mg/mL to 12.5 mg/mL. The authors found that mixing of antiobiotics such as chloramphenicol and gentamicin with V. madagascariensis extracts resulted in significant antibacterial properties by reducing the MICs [72]. These antibacterial activities exhibited by different extracts of V. madagascariensis corroborate the traditional use of the species as herbal concoction against bacterial and other microbial infections causing bloody diarrhoea and gonorrhoea in Tanzania [45], carbuncle and dysentery in Mauritius [14, 48], mouth infections in Kenya and Mauritius [48, 58], and stomach problems in Kenya [58].

Table 6: Summary of biological properties of Vangueria madagascariensis extracts.

Property assessed
Extract
Plant part
Model
Biological effects
Reference

Antibacterial
Decoction extracts
Ripe fruit
Disc diffusion
Active against Staphylococcus aureus with 10.7 ± 1.2 mm zone of inhibition
[13]

Unripe fruit
Disc diffusion
Active against Escherichia coli with 12.7 ± 0.6 mm zone of inhibition
[13]

Methanol
Leaf
Disc diffusion
Active against Escherichia coli and Staphylococcus aureus with 10.0 ± 2.0 mm and 11.7 ± 1.5 mm zones of inhibition, respectively
[13]

Seed
Disc diffusion
Active against Staphylococcus aureus with 8.3 ± 1.5 mm zone of inhibition
[13]

Decoction extracts
Ripe fruit
Microtitre dilution broth method
Active against Staphylococcus aureus with an MIC value of 12.5 mg/mL
[13]

Unripe fruit
Microtitre dilution broth method
Active against Escherichia coli with an MIC value of 25.0 mg/mL
[13]

Methanol
Leaf
Microtitre dilution broth method
Active against Escherichia coli and Staphylococcus aureus with MIC values of 6.3 mg/mL and 12.5 mg/mL, respectively
[13]

Seed
Microtitre dilution broth method
Active against Staphylococcus aureus with an MIC value of 25.0 mg/mL
[13]

Decoction extracts
Fruit
Microtitre dilution broth method
Active against Streptococcus group A with an MIC value of <0.1 mg/mL, Escherichia coli and Streptococcus group B (0.78 mg/mL), Acinetobacter spp., Proteus spp., and Staphylococcus aureus (1.6 mg/mL), Enterococcus faecalis and methicillin-resistant Staphylococcus aureus (MRSA) (3.1 mg/mL), and Klebsiella spp. (12.5 mg/mL)
[72]

Leaf
Microtitre dilution broth method
Active against Streptococcus group A and Streptococcus group B with an MIC value of 0.8 mg/mL, Enterococcus faecalis, Escherichia coli, Klebsiella spp., and Staphylococcus aureus (3.1 mg/mL), and Proteus spp. and methicillin-resistant Staphylococcus aureus (MRSA) (6.3 mg/mL)
[72]

Methanol
Fruit
Microtitre dilution broth method
Active against Streptococcus group A with an MIC value of 0.8 mg/mL, Streptococcus group B (1.6 mg/mL), Acinetobacter spp., Enterococcus faecalis, Proteus spp., and Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) (3.1 mg/mL), Escherichia coli (6.3 mg/mL), and Klebsiella spp. (12.5 mg/mL)
[72]

Leaf
Microtitre dilution broth method
Active against Enterococcus faecalis, Streptococcus group A and Streptococcus group B with an MIC value of <0.2 mg/mL, Escherichia coli, Klebsiella spp., Proteus spp., and Staphylococcus aureus (3.1 mg/mL), and methicillin-resistant Staphylococcus aureus (MRSA) (6.3 mg/mL)
[72]

Aqueous
Leaf
Agar well diffusion method
Active against Staphylococcus aureus with 6 mm zone of inhibition, Bacillus cereus (8 mm), Escherichia coli (10 mm), and Klebsiella pneumoniae (13 mm)
[60]

Dichloromethane
Leaf
Agar well diffusion method
Active against Staphylococcus aureus with 6 mm zone of inhibition, Escherichia coli (9 mm), Pseudomonas aeruginosa (10 mm), Bacillus cereus (11 mm), and Klebsiella pneumoniae (15 mm)
[60]

Ethanol
Leaf
Agar well diffusion method
Active against Staphylococcus aureus with 4 mm zone of inhibition, Micrococcus luteus (7 mm), Bacillus cereus (8 mm), Escherichia coli (10 mm), Pseudomonas aeruginosa (11 mm), and Klebsiella pneumoniae (17 mm)
[60]

n-Butanol
Leaf
Agar well diffusion method
Active against Staphylococcus aureus with 5 mm zone of inhibition, Escherichia coli (10 mm), and Klebsiella pneumoniae (14 mm)
[60]

n-Hexane
Leaf
Agar well diffusion method
Active against Staphylococcus aureus with 6 mm zone of inhibition, Micrococcus luteus (7 mm), Bacillus cereus (8 mm), Escherichia coli (9 mm), and Klebsiella pneumoniae (12 mm)
[60]

Aqueous
Stem bark
Agar well diffusion method
Active against Micrococcus luteus with 8 mm zone of inhibition, Bacillus cereus with Klebsiella pneumoniae (9 mm), Pseudomonas aeruginosa (10 mm), and Escherichia coli (11 mm)
[60]

Dichloromethane
Stem bark
Agar well diffusion method
Active against Micrococcus luteus with 8 mm zone of inhibition, Pseudomonas aeruginosa (9 mm), Escherichia coli and Staphylococcus aureus (10 mm), Bacillus cereus (12 mm), and Klebsiella pneumoniae (13 mm)
[60]

Ethanol
Stem bark
Agar well diffusion method
Active against Micrococcus luteus with 8 mm zone of inhibition, Escherichia coli (10 mm), Bacillus cereus and Pseudomonas aeruginosa (11 mm), Staphylococcus aureus (14 mm), and Klebsiella pneumoniae (15 mm)
[60]

n-Hexane
Stem bark
Agar well diffusion method
Active against Staphylococcus aureus with 9 mm zone of inhibition, Bacillus cereus (10 mm), and Klebsiella pneumoniae (12 mm)
[60]

Aqueous
Leaf
Agar well diffusion method
Active against Escherichia coli with an MIC value of 15 µg/ml, Klebsiella pneumoniae (30 µg/ml), Staphylococcus aureus (40 µg/ml), and Bacillus cereus (75 µg/ml)
[60]

Dichloromethane
Leaf
Agar well diffusion method
Active against Klebsiella pneumoniae with an MIC value of 20 µg/ml, Escherichia coli and Staphylococcus aureus (25 µg/ml), Bacillus cereus (35 µg/ml), and Pseudomonas aeruginosa (50 µg/ml)
[60]

Ethanol
Leaf
Agar well diffusion method
Active against Klebsiella pneumoniae with an MIC value of 15 µg/ml, Staphylococcus aureus (40 µg/ml), Bacillus cereus and Escherichia coli (50 µg/ml), and Micrococcus luteus and Pseudomonas aeruginosa (55 µg/ml)
[60]

n-Butanol
Leaf
Agar well diffusion method
Active against Klebsiella pneumoniae with an MIC value of 25 µg/ml, Staphylococcus aureus (36 µg/ml), and Escherichia coli (75 µg/ml)
[60]

n-Hexane
Leaf
Agar well diffusion method
Active against Bacillus cereus with an MIC value of 6.3 µg/ml, Klebsiella pneumoniae (25 µg/ml), Staphylococcus aureus (37 µg/ml), Escherichia coli (60 µg/ml), and Micrococcus luteus (75 µg/ml)
[60]

Aqueous
Stem bark
Agar well diffusion method
Active against Pseudomonas aeruginosa with an MIC value of 25 µg/ml, Escherichia coli and Klebsiella pneumoniae (35 µg/ml), and Bacillus cereus and Micrococcus luteus (75 µg/ml)
[60]

Dichloromethane
Stem bark
Agar well diffusion method
Active against Escherichia coli with an MIC value of 20 µg/ml, Klebsiella pneumoniae (24 µg/ml), Pseudomonas aeruginosa (25 µg/ml), Staphylococcus aureus (33 µg/ml), Micrococcus luteus (50 µg/ml), and Bacillus cereus (55 µg/ml)
[60]

Ethanol
Stem bark
Agar well diffusion method
Active against Klebsiella pneumoniae and Staphylococcus aureus with an MIC value of 20 µg/ml, Escherichia coli, Micrococcus luteus, and Pseudomonas aeruginosa (25 µg/ml), and Bacillus cereus (50 µg/ml)
[60]

n-Hexane
Stem bark
Agar well diffusion method
Active against Klebsiella pneumoniae with an MIC value of 24 µg/ml, Staphylococcus aureus (35 µg/ml), and Bacillus cereus (65 µg/ml)
[60]

Antidiabetic
Decoction extract
Fruit, leaf, and seed
α-Amylase
Decoctions active with IC₅₀ values of 1.1 mg/mL (leaf), 5.3 mg/mL (unripe fruit), 6.8 mg/mL (seed), and 29.6 mg/mL (ripe fruit)
[13]

Fruit and leaf
α-Glucosidase
Decoctions active with IC₅₀ values of 0.5 mg/mL (unripe fruit), 0.6 mg/mL (leaf), and 15.7 mg/mL (ripe fruit)
[13]

Methanol
Fruit, leaf, and seed
α-Amylase
Extracts active with IC₅₀ values of 1.2 mg/mL (unripe fruit), 1.7 mg/mL (leaf), 3.8 mg/mL (seed), and 7.7 mg/mL (ripe fruit)
[13]

Fruit, leaf, and seed
α-Glucosidase
Extracts active with IC₅₀ values of 0.4 mg/mL (unripe fruit), 3.3 mg/mL (ripe fruit), 6.2 mg/mL (leaf), and 46.3 mg/mL (seed)
[13]

Ethanol
Bark
α-Amylase
Extracts active with IC₅₀ values of 11.6 µg/mL
[73]

Bark
α-Glucosidase
Extracts active with IC₅₀ values of 1.8 µg/mL
[73]

Antifungal
Several extracts
Leaf
Agar well diffusion method
n-Butanol and n-hexane active against Candida albicans with 9 mm zone of inhibition, ethanol (10 mm), aqueous (14 mm), and dichloromethane (20 mm)
[60]

Stem bark
Agar well diffusion method
Aqueous and n-hexane active against Candida albicans with 14 mm zone of inhibition, ethanol (18 mm), and dichloromethane (21 mm)
[60]

Leaf
Agar well diffusion method
Ethanol extract active against Candida albicans with an MIC value of 13 µg/ml, dichloromethane (14 µg/ml), aqueous (18 µg/ml), n-butanol (30 µg/ml), and n-hexane (35 µg/ml)
[60]

Stem bark
Agar well diffusion method
Ethanol extract active against Candida albicans with an MIC value of 15 µg/ml, dichloromethane (18 µg/ml), n-hexane (30 µg/ml), and aqueous (55 µg/ml)
[60]

Chloroform
Fruit
Agar well diffusion method
Chloroform extract active against Aspergillus niger and Candida albicans with 15 mm and 14 mm zones of inhibition, respectively
[74]

Antioxidant
Decoction
Fruit, leaf, and seed
DPPH
Extracts active with IC₅₀ values of 132.8 µg/mL (leaf), 602.5 µg/mL (ripe fruit), and 612.5 µg/mL (unripe fruit and seed)
[13]

Methanol
Fruit, leaf, and seed
DPPH
Extracts active with IC₅₀ values of 9.0 µg/mL (leaf), 10.0 µg/mL (unripe fruit), 48.5 µg/mL (ripe fruit), and 105.9 µg/mL (seed)
[13]

Decoction
Fruit, leaf, and seed
FRAP
Exhibited antioxidant activity with 319.2 (seed), 322.9 (ripe fruit), 330.8 (unripe fruit), and 350.4 (leaf) mM Trolox equivalent (TE)/g fresh weight
[13]

Methanol
Fruit, leaf, and seed
FRAP
Exhibited antioxidant activity with 346.7 (seed), 357.1 (ripe fruit), 361.3 (unripe fruit), and 372.5 (leaf) mM Trolox equivalent (TE)/g fresh weight
[13]

Decoction extracts
Fruit, leaf, and seed
HOCl
Active with IC50 values of 235.6 µg/mL (leaf), 275.3 µg/mL (unripe fruit), 982.4 µg/mL (ripe fruit), and 6656.4 µg/mL (seed)
[13]

Methanol
Fruit, leaf, and seed
HOCl
Active with IC₅₀ values of 223.0 µg/mL (unripe fruit), 382.1 µg/mL (leaf), 418.9 µg/mL (ripe fruit), and 941.5 µg/mL (seed)
[13]

Decoction extracts
Fruit, leaf, and seed
OH
Active with IC₅₀ values of 157.2 µg/mL (unripe fruit), 261.0 µg/mL (ripe fruit), 289.0 µg/mL (leaf), and 803.8 µg/mL (seed)
[13]

Methanol
Fruit, leaf, and seed
OH
Active with IC₅₀ values of 0.1 µg/mL (leaf), 0.3 µg/mL (ripe and unripe fruits), and 22.4 µg/mL (seed)
[13]

Antioxidant
Decoction extracts
Fruit, leaf, and seed
NO
Active with IC₅₀ values of 241.2 µg/mL (leaf), 436.2 µg/mL (unripe fruit), 2367.4 µg/mL (ripe fruit), and 6092.4 µg/mL (seed)
[13]

Methanol
Fruit, leaf, and seed
NO
Active with IC₅₀ values of 43.2 µg/mL (leaf), 91.4 µg/mL (unripe fruit), 219.1 µg/mL (ripe fruit), and 1103.2 µg/mL (seed)
[13]

Decoction extracts
Fruit, leaf, and seed
Iron chelation
Active with IC₅₀ values of 0.3 µg/mL (seed), 0.6 µg/mL (ripe fruit), 1.0 µg/mL (unripe fruit), and 2.5 µg/mL (leaf)
[13]

Methanol
Fruit, leaf, and seed
Iron chelation
Active with IC₅₀ values of 0.0009 µg/mL (seed), 0.002 µg/mL (leaf), 0.06 µg/mL (ripe fruit), and 0.07 µg/mL (unripe fruit)
[13]

Methanol
Bark, leaf, and seed
DPPH
Extracts active with IC₅₀ values of 7.8 µg/ml (leaf), 31.3 µg/ml (seed), and 62.5 µg/ml (bark)
[17]

Methanol
Bark, leaf, and seed
ORAC
Extracts active with 44.9 µM of Trolox (seed), 47.1 µM of Trolox (bark), and 72.7 µM of Trolox (leaf)
[17]

Antiplasmodial
Methanol
Leaf
G-³H hypoxanthine
Active against Plasmodium falciparum with IC₅₀ values of 13.4 µg/ml and 34.0 µg/ml against D6 and W2 strains, respectively
[55, 56]

Cytotoxicity
Crude extracts
Stem bark
MTT assay
Extracts active with EC₅₀ values of 22.8 µg/ml (MCF-7), 28.4 µg/ml (HepG2), 34.4 µg/ml (PC-3), 42.5 µg/ml (A549), 44.5 µg/ml (WRL-68), 53.2 µg/ml (HT-29), and 64.7 µg/ml (WI-38T)
[17]

Toxicity
Ethanol
Leaf and stem bark
In vivo animal toxicity activities
All extracts appear to be nontoxic with LD₅₀ values of 3.8 g/kg
[60]

4.2. Anticonvulsant Activities

The activities of the different fractions and the total ethanolic extracts of both leaves and stem bark of V. madagascariensis on the central nervous system were evaluated by performing assays of their effect on motor coordination (rotarod test) and pentylene tetrazole-induced convulsion [60]. The total ethanolic extracts as well as the other fractions of both leaves and stem-bark attained a central nervous system depressant activity. The n-butanol and n-hexane extracts of the leaves, n-hexane and chloroform extracts the stem-bark at 400 mg/kg have anticonvulsant properties against pentylene tetrazole induced convulsions in comparison with carbamazepine. The n-butanol and n-hexane extracts of the leaves, n-hexane and chloroform extracts of the stem-bark at 400 mg/kg exhibited anticonvulsant properties against pentylene tetrazole induced convulsions in rats in comparison with carbamazepine [60]. The anticonvulsant properties demonstrated by the extracts of V. madagascariensis corroborate the usage of stem bark of the species as herbal concoction against convulsions in Tanzania [60].

4.3. Antidiabetic Activities

Ramalingum and Mahomoodally [14] evaluated antidiabetic activities of methanol and crude fruit, leaf and seed extracts of V. madagascariensis using α-amylase, α-glucosidase and a modified glucose based colorimetric and glucose movement assays with acarbose as the control (Table 6). The crude and methanol extracts exhibited inhibitory activities against α-amylase with half maximal inhibitory concentration (IC₅₀) values varying from 1.1 mg/mL to 29.6 mg/mL which was comparable to acarbose with IC₅₀ value of 0.1 mg/mL. The extracts that exhibited activities against α-glucosidase where unripe fruit decoction, ripe fruit methanol, unripe fruit methanol, leaf decoction exhibited IC₅₀ values stretching from 0.4 mg/mL to 3.3 mg/mL which were significantly lower than IC₅₀ value of 5.0 mg/mL demonstrated by the control, acarbose. The kinetic evaluations showed a mixed non-competitive type of inhibition. Beidokhti et al. [73] evaluated the inhibition of pancreatic α-amylase and yeast α-glucosidase by ethanolic bark and leaf extracts of V. madagascariensis (Table 6). The showed activities against both α-glucosidase and α-amylase and characterized by IC₅₀ values of 1.8 µg/mL and 11.6 µg/mL, respectively [73]. The observed antidiabetic activities of V. madagascariensis extracts support the use of the bark, leaves, fruits and roots of the species as herbal medicine against diabetes in Madagascar, Mauritius and Sudan [14, 47–50].

4.4. Antifungal Activities

Bishay et al. [60] assessed antifungal properties of bark and leaf aqueous, n-hexane, chloroform, ethyl acetate extracts of V. madagascariensis against Candida albicans using the modified diffusion method with clotrimazole (5 µg/ml) as the positive control (Table 6). The bark and leaf extracts showed antifungal properties with zone of inhibition stretching from 9 mm to 20 mm which was comparable to zone of inhibition of 14 mm demonstrated by clotrimazole, the control. The MIC values stretched from 13.0 µg/ml to 55.0 µg/ml and clotrimazole, the control exhibited MIC value of 4.0 µg/ml [60]. Similarly, Karim et al. [74] assessed antifungal properties of chloroform fruit extract of V. madagascariensis against Candida albicans and Aspergillus Niger using agar diffusion assay with ampicillin as positive control (Table 6). The chloroform fruit extract showed activities with zone of inhibition stretching from 14 mm to 15 mm [74]. These antifungal activities displayed by the different extracts of V. madagascariensis demonstrate the potential of the species in the management of fungal and microbial infections.

4.5. Anti-inﬂammatory Activities

Bishay et al. [60] assessed anti-inﬂammatory properties of bark and leaf aqueous, ethyl acetate, chloroform and n-hexane extracts of V. madagascariensis using the carrageenan-induced rat paw oedema model. Potent anti-inflammatory activities were observed after 2 hrs and continued for 4 hrs with all the extracts [60]. These findings corroborate the traditional use of V. madagascariensis as herbal concoction for abdominal pains in Tanzania [45], back pain in Kenya [46] and other various inflammatory ailments and diseases including skin infections and body injury that may lead to cell damage and death.

4.6. Antioxidant Activities

Ramalingum and Mahomoodally [13] evaluated antioxidant properties of methanol and crude fruit, leaf and seed extracts of V. madagascariensis using DPPH (1, 1-Diphenyl-2-picrylhydrazyl) free radical scavenging, hypochlorus acid (HOCl) scavenging, ferric reducing antioxidant power (FRAP), hydroxyl (⋅OH) radical scavenging or deoxyribose, nitric oxide radical (NO) scavenging and iron chelating property assays (Table 6). The methanol leaf, unripe and ripe fruit extracts exhibited antioxidant properties with IC₅₀ values stretching from 9.0 µg/mL to 48.5 µg/mL which was comparable to ascorbic acid with IC₅₀ value of 0.001 µg/mL. All the extracts exhibited activities in the reduction of Fe⁴⁺ to Fe²⁺, confirming antioxidant properties with leaf methanol being the most active and seed decoction being the least active. The methanol unripe fruit extract exhibited the highest HOCl scavenging properties with IC₅₀ value of 223.0 µg/mL which was comparable to that of ascorbic acid, the control which exhibited IC₅₀ value of 46.0 µg/mL. The methanol leaf, unripe and ripe fruit extracts exhibited ˙OH scavenging properties with IC₅₀ values stretching from 0.1 µg/mL to 0.3 µg/mL which were lower than that of α-tocopherol, the control which exhibited IC₅₀ value of 0.5 µg/mL. The leaf and unripe fruit crude extracts as well as methanolic leaf, ripe and unripe fruit extracts exhibited NO scavenging properties with IC₅₀ values stretching from 43.2 µg/mL to 436.2 µg/mL which were lower than that of ascorbic acid, the control which exhibited IC₅₀ value of 546.5 µg/mL. All the extracts exhibited considerable iron chelating properties with IC₅₀ values stretching from 0.0009 µg/mL to 2.5 µg/mL which were comparable to the positive control EDTA which exhibited IC₅₀ value of 0.001 µg/mL [13]. Mustafa et al. [17] assessed antioxidant properties of bark, leaf and seed extracts of V. madagascariensis using DPPH radical scavenging assay and oxygen radical absorbance capacity (Table 6). The DPPH assay revealed activities of leaf, seed and bark extracts with IC₅₀ values of 7.8, 31.3 and 62.5 μg/ml, respectively, which were comparable to IC₅₀ value of 3.1 μg/ml exhibited by ascorbic acid, the control. The oxygen radical absorbance ability findings revealed that the leaf extract demonstrated higher levels of antioxidant properties of 72.7 μM of trolox than the control, quercetin (5 μg/ml) which showed activity of 59.0 μM of trolox), while the bark and seed extracts showed activities of 47.1 μM of trolox and 44.9 μM of trolox, respectively [17]. The documented antioxidant activities of V. madagascariensis extracts are probably due to flavonoids, phenolics and proanthocyanidins detected in fruits, leaves and stems of the species [14, 17, 60].

4.7. Cytotoxicity Activities

Mustafa et al. [17] assessed cytotoxicity properties of the bark, leaf and seed extracts of V. madagascariensis using the MTT [3-(4, 5dimethylthiazole-2-yl)2, 5-diphenyltetrazolium bromide] assay using human breast carcinoma (MCF-7), non-small cell lung cancer (A549), prostate adenocarcinoma (PC-3), human hepatocellular carcinoma (HepG2), human colon adenocarcinoma (HT-29), normal hepatic (WRL-68) and normal lung fibro blast (WI-38T) cells (Table 6). Test agents induced cell cytotoxicity in a concentration dependent trend with half maximal effective concentration (EC₅₀) values stretching from 22.8 μg/mL to 64.7 μg/mL [17]. These findings corroborate the traditional use of V. madagascariensis as herbal concoction for tumour in Sudan [59].

4.8. Antimalarial and Antiplasmodial Activities

Muthaura et al. [55] assessed in vivo antimalarial properties of water and methanol stem bark of V. madagascariensis against Plasmodium berghei strain ANKA using a four-day suppressive assay with chloroquine as positive control. The in vivo studies showed weak activities with chemo-suppression of parasitaemia in Plasmodium berghei infected mice of 26.0% to 39.0% which was much lower than 99.9% exhibited by chloroquine [55]. Similarly, Muthaura et al. [55] assessed antiplasmodial properties of water and methanol stem bark of V. madagascariensis against chloroquine sensitive (D6) and resistant (W2) Plasmodium falciparum clones using the [G-³H]hypoxanthine incorporation assay with artemisinin and chloroquine as positive controls (Table 6). The methanol extracts exhibited moderate and weak activities with IC₅₀ values of 13.4 µg/mL and 34.0 µg/mL against D6 and W2 strains, respectively. These results were higher than IC₅₀ values demonstrated by the reference drugs artemisinin (D6 = 0.9 ng/mL, W2 = 3.4 ng/mL) and chloroquine (D6 = 9.0 ng/mL, W2 = 31.3 ng/mL) [55]. In another study, Muthaura et al. [56] assessed antiplasmodial properties of water and methanol stem bark of V. madagascariensis against chloroquine sensitive (D6) and resistant (W2) Plasmodium falciparum clones using the (G-³H) hypoxanthine incorporation assay with artemisinin and chloroquine as positive controls (Table 6). The methanol extracts demonstrated moderate and weak activities with IC₅₀ values of 13.3 µg/mL and 33.9 µg/mL against D6 and W2 strains, respectively. These results were higher than IC₅₀ values demonstrated by the reference drugs artemisinin (D6 = 0.9 ng/mL, W2 = 3.4 ng/mL) and chloroquine (D6 = 9.0 ng/mL, W2 = 31.3 ng/mL) [56]. Therefore, V. madagascariensis extracts showed promising antimalarial and antiplasmodial activities and these findings corroborate the traditional usage of the bark, roots and stem bark of the species as remedies against malaria in Kenya and Tanzania [8, 45, 51, 53–57].

4.8. Toxicity Activities

Bishay et al. [60] evaluated oral acute toxicity of bark and leaf n-hexane, chloroform, ethyl acetate extracts of V. madagascariensis by administering doses of 10 mg/kg, 100 mg/kg and 1000 mg/kg i.p. to male albino rats (Table 6). The treated animals were monitored for 24 hrs for symptoms of toxicity such as writhing, loss of motor co-ordination, irritability, hypothermia, sedation followed by deep sleep and finally death. The median lethal dose (LD₅₀) values of 3.8 g/kg for both leaf and stem-bark extracts appear to suggest that the extracts of the species are safe to use as herbal medicines [60]. Muthaura et al. [55] assessed the acute, subacute and chronic toxicity of V. madagascariensis stem bark extracts by oral administration in female Swiss mice. The behaviour of mice was observed for 1 hour, intermittently for 4 hours, 24 hours and 14 days noting for any signs of toxicity and the latency of death. The extracts did not cause any mortality or signs of toxicity at any dose level up to the highest dose tested of 5000 mg/kg [55]. Since V. madagascariensis is widely utilized as both food and herbal medicine, there is need to ascertain toxicological properties of the species using different plant parts against several cell lines using both in vitro toxicological assays and in vivo studies.

5. Conclusion

Vangueria madagascariensis is an important functional food and source of nutraceutical ingredients in tropical Africa. Significant breakthrough has been made in the last 30 years elucidating the nutritional, phytochemical and pharmacological properties of the species. However, there are still some research gaps regarding correlating the nutritional and phytochemical properties of the species with its food value and medicinal applications. Detailed studies on the phytochemistry, pharmacokinetics, in vivo and clinical research are required. Further research on the antinutritive, enzymatic and molecular effects of V. madagascariensis fruits and kernel oil on human health will be needed to motivate further interest in the use of these products as food sources, additives and health promoting products. Given the situation that V. madagascariensis is used as herbal medicine in combination with other plant species such as Azadirachta indica, Ipomoea pes-caprae, Jatropha curcas, Sporobolus africanus and Toddalia asiatica, there is need to investigate the possibility of synergetic effects of the combined extracts. Since V. madagascariensis is a valuable functional food and nutraceutical plant species in tropical Africa, there is need to establish the toxicity and/or any side effects that can arise when the species and its products are used as functional food and sources of nutraceutical ingredients and/or as herbal medicines.

Conflicts of Interest

The author declares that there are no conflicts of interest regarding the publication of this paper.

Acknowledgments

The author would like to express his gratitude to the National Research Foundation (NRF), South Africa, and Govan Mbeki Research and Development Centre (GMRDC), University of Fort Hare, for financial support to conduct this study.

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