Journal of Chemistry
Volume 2020 (2020), Article ID 8908301, 9 pages
https://doi.org/10.1155/2020/8908301

Research Article

Bioactive Characteristics of Wild Berberis vulgaris and Berberis crataegina Fruits

Arzu Yaşar Eroğlu,¹ Özlem Çakır,¹ Mustafa Sağdıç,² and Enes Dertli³

¹Department of Food Engineering, Faculty of Engineering, Bayburt University, Dedekorkut Campus, Bayburt 69000, Turkey
²Department of Elementary Education, Faculty of Education, Yildiz Technical University, Davutpasa Campus, Esenler, Istanbul 34210, Turkey
³Department of Food Engineering, Faculty of Chemical and Metallurgical Engineering, Yildiz Technical University, Davutpasa Campus, Esenler, Istanbul 34210, Turkey

Correspondence should be addressed to Özlem Çakır; ocakir@bayburt.edu.tr

Received 17 April 2020; Accepted 5 June 2020; Published 24 June 2020

Academic Editor: Jorge Barros-Velázquez

Copyright © 2020 Arzu Yaşar Eroğlu et al. 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.

There is an increasing trend to find novel sources of products with high antioxidant capacity and wild fruits are very good examples for these sources. In this study, fruits of Berberis vulgaris and Berberis crataegina, naturally grown in Bayburt province of Turkey, were tested for their physicochemical features, antioxidant capacities, phenolic compound profiles, and antimicrobial activities. The physicochemical analysis of the fruits revealed that the dry matter content, ash content, pH, and aw values were between 28.47% and 41.61%, 0.65% and 2.13%, 2.44 and 3.25, and 0.996 and 0.97, respectively. The total phenolic content of the fruits was determined by the Folin–Ciocalteu methodology, and for the determination of the antioxidant capacity of the fruits, DPPH, ABTS, and β-carotene bleaching methods were performed and a high level of antioxidant activity was observed. HPLC analysis was applied to identify the phenolic content of the fruits, and gallic acid and chlorogenic acid were found to be the dominant phenolic compounds in Berberis fruits. The water extracts of the Berberis fruits were tested against important foodborne pathogenic bacteria as potential antimicrobials. The extracts inhibited the growth of Bacillus cereus, Salmonella typhimurium, Yersinia enterocolitica, and Staphylococcus aureus at significant rates. This study revealed the potential antioxidant and antimicrobial characteristics of wild-type B. vulgaris and B. crataegina that can be used for different future applications.

1. Introduction

There is an increasing demand for different sources for food production and nutritious wild fruits are very suitable sources for food industry [1]. Due to this and many other advantageous features, scientific studies on the nutritional content and medicinal values of different wild edible fruits grown in various parts of the world are of great interest [2]. These types of fruits are also among the important food sources due to their antioxidant capacity and they might also have antimicrobial features. Berberidaceae family consists of the most important natural wild fruits, and they comprise about 14 genera and 700 species [3]. Berberis is one of the genera of this family.

The Berberis genus has about 500 species in the world [4]. Wild barberry is found in nature on stony soils and between forest openings or bushes at altitudes of 500–1500 m. There are four types of Berberis species naturally grown in Turkey, which are B. vulgaris L., B. crataegina DC., B. cretica L., and B. integerrima B. From these species, B. vulgaris L. and B. crataegina DC. were selected for further studies in this study. B. vulgaris L. are generally grown in the northern Anatolia provinces such as Kastamonu and Tokat as well as along Çoruh and Kelkit valleys alongside the Black Sea regions [5]. The yellow bunch of flowers that blossom in April or May consist of 15–25 flowers. Its fruits are 8–12 mm tall with an elliptical structure, turning into a beautiful red color when they ripen. The fruit is the most used organ of this plant in traditional and modern medicine [6]. For medical purposes, studies have been conducted on the fruits and roots of B. vulgaris. Berberine is extracted as an alkaloid from the roots and bark of B. vulgaris [7]. Fruit extracts from B. vulgaris L. possess various beneficial properties, which are beneficial in both cardiovascular and nervous systems, thus presenting a potential use in the treatment of some neuronal disorders such as hypertension, epilepsy, and contraction [8, 9]. B. crataegina DC. can possibly grow in small and large group bushes located between the arid and rocky slopes at altitudes of 800–1500 m. In some occasions, the fruits are found individually, while in others they appear in the form of a bunch of grapes. Their taste is slightly sour. The B. crataegina fruits contain tannins, organic acids, high levels of vitamin C, and anthocyanins [10]. It is stated that the berberine alkaloid and extracts obtained from the B. crataegina DC. plant have a strong antifungal activity [11].

In this study, fruits of B. vulgaris L. and B. crataegina DC. were collected from Bayburt province of Turkey, and the physicochemical characteristics, antioxidant capacities, phenolic substance profiles, and antimicrobial activities of the fruit extracts were determined. General appearances of B. vulgaris L. and B. crataegina DC. are presented in Figures 1(a) and 1(b), respectively.

(a)

(b)

Figure 1: Fruits of Berberis vulgaris L. (a) and Berberis crataegina DC. (b).

The physicochemical characteristics of the wild fruits were determined in terms of dry matter content, water-soluble dry matter content, pH, water activity (aw), and ash content. The antioxidant capacities of the fruits were determined using DPPH, ABTS, and β-carotene bleaching methods and total phenolic content of the fruits was determined by the Folin–Ciocalteu methodology. High-performance liquid chromatography (HPLC) analysis was applied to determine the phenolic compounds presented in the tested fruits. Finally, the antimicrobial activity of the water extracts of the Berberis fruits were tested against foodborne pathogenic bacteria including Bacillus cereus, Salmonella typhimurium, Yersinia enterocolitica, and Staphylococcus aureus.

2. Materials and Methods

2.1. Collection of Wild Fruits

B. vulgaris L. and B. crataegina DC. fruits collected from 11 different regions of Bayburt geographical regions (Turkey) were identified botanically at the Food Engineering Department of Bayburt University (Turkey). The fruits were kept in suitable containers, brought to the laboratory, and stored at −80°C until further analysis. Photographs of Berberis fruits tested in this study are presented in Figure 2.

Figure 2: Berberis vulgaris L. and Berberis crataegina DC. samples used in the research.

2.2. Determination of Physicochemical Properties of Berberis Fruits

For the dry matter analysis, 3 g of fruit sample was weighed and dried at 105°C and the dry matter content (%) was determined by comparison of dry weight/fresh weight. To determine the water-soluble dry matter content, the fruit pulps were filtered through cheesecloth and dropped into the prism of the Abbe refractometer (Model Ra 250HE, Kyoto Electronics Manufacturing Co., Ltd., Japan) and the amounts of water-soluble dry matter at 20°C were recorded. To determine the ash content of the fruits, samples were placed to an ash oven at 500°C, and the burning process continued until a light gray-white color formed in the samples. The weight of the samples was calculated following the burning process and the ash content % was determined. The pH values of the fruits were measured with pH meter (Jenco Electronics, 6173 brand) from the fruit juice obtained by crushing the fruits in porcelain mortar. The water activity (aw) of the homogenized fruit samples was determined with the temperature-controlled Aqua Lab brand (Decagon Devices, Inc., Pullman, WA) water activity device.

2.3. Preparation of Fruit Extracts

For the determination of the antioxidant activity of the Berberis fruits, the extraction process of Meng et al. [12] was applied with slight modifications. Briefly, at first, drying of fruits was conducted at 55°C for 3 days. Dried fruits were slightly crushed in mortar and 3 g from the slightly crushed fruits was weighed. Both water and ethanol-water (80 : 20) extracts were prepared for the antioxidant activity (Table 1) by adding 30 ml of distilled water and ethanol:water (80 : 20) to 3 g fruits and solutions were left in shaker for 15 hours. At the end of the period, samples were moved into centrifuge tubes and centrifuged at 5000 rpm for 15 minutes at 4°C. The centrifuged samples were filtered through 110 mm filter papers. Fruit extracts obtained after extraction were stored in separate tubes at −20°C until use.

Table 1: Location, variety, and codes of the fruits used in the research.

Collected regions
Variety
Codes of the extracts

Ethanolic
Water

Darıca village
Berberis vulgaris L.
Bv-EtOH-1
Bv-W-1

Aslandede village
Berberis vulgaris L.
Bv-EtOH-2
BvW2

Masat village 1
Berberis vulgaris L.
Bv-EtOH-3
Bv-W-3

Aydıntepe district
Berberis vulgaris L.
Bv-EtOH-4
Bv-W-4

Alapelit village
Berberis vulgaris L.
Bv-EtOH-5
Bv-W-5

Masat village 2
Berberis vulgaris L.
Bv-EtOH-6
Bv-W-6

Çalıdere village
Berberis vulgaris L.
Bv-EtOH-7
Bv-W-7

Kopuz village
Berberis vulgaris L.
Bv-EtOH-8
Bv-W-8

Yaylapınar village
Berberis crataegina DC.
Bc-EtOH-9
Bc-W-9

Dağtarla village
Berberis crataegina DC.
Bc-EtOH-10
Bc-W-10

Bayburt city center
Berberis crataegina DC.
Bc-EtOH-11
Bc-W-11

2.4. Determination of Antioxidant Characteristics of Berberis Fruits

The total phenolic content, antioxidant activity (DPPH •, β-carotene bleaching, and ABTS • +), and phenolic compositions of the fruit extracts were determined. Table 1 shows the identification used in the display for the ease of writing of fruits extracted with ethanol or water in terms of location and variety. The β-carotene bleaching method to test the total antioxidant activities of fruit samples in the extract obtained with ethanol : water (80 : 20) and water was applied as described previously [13]. Butylated hydroxyanisole (BHA) was used as the standard substance. The degradation rate (DR) was calculated according to first-order kinetics using the following equation:

where ln is natural log, a is the initial absorbance (470 nm) at time 0, b is the absorbance (470 nm) at 100 min, and t is time.

The antioxidant activity (AA) was expressed as percent of inhibition relative to the control, using the following formula:

DPPH • radical scavenging activity was performed according to Gülçin [14]. The absorbance of the samples was recorded at 517 nm. The reduced absorbance value gives the remaining DPPH solution or the free radical scavenging activity.

For ABTS •+ analysis, the method described by Huang et al. [15] was slightly modified and applied. Briefly, 0.008 g of ABTS was dissolved in distilled water and mixed with 13.2 mg of potassium persulfate to obtain the dark blue solution following 16 hours of incubation. This solution was diluted with ethanol to obtain OD 734 nm of 0.7 and then 100 μl sample was mixed with 2.4 ml ABTS •+ solution and kept at room temperature for 6 minutes; then its absorbance was recorded. In DPPH and ABTS methods, the dilution of each extract (6.67 mg/ml) was prepared in ethanol/water (v/v) and the % inhibition values were calculated according to the following equation:

2.5. Determination of the Total Phenolic Content of Fruits

The Folin–Ciocalteu (FC) methodology was applied to determine the total phenolic content of the fruit extracts using the method described by Gülçin et al. [16]. Briefly, 1 ml taken from the prepared extracts was mixed with 5 ml FC reagent (1 : 10). After placing for 3 minutes at room temperature, 4 ml of 7.5% Na₂CO₃ solution was added and the absorbance was recorded at 760 nm after incubation in the dark for 90 minutes at room temperature. Calibration curves were generated using gallic acid as standard and the results were presented as gallic acid equivalent (microgram GAE/mg sample).

2.6. Determination of Phenolic Compounds

The phenolic content of the fruit extracts was determined by HPLC analysis using a Photodiode Array Detector (PDA) attached to Shimadzu SPP-M20A HPLC system [17]. Samples were passed through 0.45 μm membrane filter and transferred to HPLC vials at 100 μl volume. An Inertsil ODS-3, 5 μm, (25 × 4.6 mm) column was used with mobile phase of gradient system of methanol (A) and water + 2% acetic acid (B) with a column temperature of 30°C. The phenolic compound was detected at 254 nm (in the range of 210–360 nm). Standards included in the analysis were gallic acid, 4-hydroxybenzoic acid, chlorogenic acid, vanillic acid, caffeic acid, syringic acid, p-coumaric acid, trans-ferulic acid, and sinapic acid.

2.7. Antimicrobial Activity of Water Extracts of Wild Fruit Extracts

For the antimicrobial activity tests, pathogenic strains Escherichia coli BC 1402, Bacillus cereus BC 6830, Salmonella typhimurium RSSK 95091, Yersinia enterocolitica ATCC 27729, and Staphylococcus aureus ATCC 25923 were grown in Tryptic Soy Broth (TSB) at 37°C aerobically. From the overnight grown bacterial cells, pathogenic strains were spread to the TSB gar plates and 20 μl of the water extracts of Berberis fruits was applied to these agar plates which were then incubated at 37°C for 24 h. Following the incubation, the inhibition zones formed due to the antimicrobial activities of the water extracts were recorded and expressed as diameters for the inhibition zone.

2.8. Statistical Analysis

In all of the data obtained, the mean values of physicochemical and biochemical parameters were compared using one-way analysis of variance (ANOVA). All data were determined as mean value ± standard deviation; was considered as statistically significant.

3. Results and Discussion

3.1. Physicochemical Characteristics of Berberis Fruits

In this study, fruits of B. vulgaris L. and B. crataegina DC. were collected from eleven different regions of Bayburt province to determine their potential technofunctional characteristics. The physicochemical properties of these fruits were determined at first in terms of dry matter content, water-soluble dry matter content, pH, aw, and ash content. Table 2 shows the physicochemical characteristics of these wild fruits. The amount of dry matter content is an important criterion in terms of the determination of the consumption status of the fruits [18]. The amount of dry matter in the collected Berberis fruits varied between 28.47% and 41.61% (Table 2). The results obtained in this study from Berberis fruits were similar to those reported by Demir [19] and Karabulut [20]. It was determined as 31.22 ± 1.177% in B. vulgaris by Demir [19] and as 9.03 ± 0.27% in B. vulgaris and 32.77 ± 2.43% in B. crataegina by Karabulut [20]. The lowest dry matter was determined from the Berberis fruits grown in Alapelit village with 28.47%, and the highest was from the central district with 41.61%. Significant levels of differences were observed among the fruits () in terms of dry matter content.

Table 2: Physicochemical properties of Berberis fruits collected from Bayburt province.

Collected regions
Dry matter (DM) %
Water-soluble DM (%)
Ash (%)
aw
pH

Darıca
29.89 ± 2.18cd
19.25 ± 0.77a
0.84 ± 0.02gh
0.938 ± 0.000bc
2.76 ± 0.02b

Aslandede
29.34 ± 0.34cd
18.10 ± 1.41a
0.68 ± 0.04h
0.947 ± 0.002a
2.84 ± 0.30ab

Masat 1
30.20 ± 1.21cd
19.55 ± 2.33a
0.99 ± 0.05fg
0.945 ± 0.001a
2.73 ± 0.03b

Aydıntepe
28.49 ± 3.27d
19.20 ± 0.14a
0.76 ± 0.05h
0.942 ± 0.001abc
2.44 ± 0.04b

Alapelit
28.47 ± 0.67d
20.40 ± 0.70a
1.45 ± 0.02cd
0.946 ± 0.002a
2.80 ± 0.14ab

Masat 2
31.17 ± 0.71cd
18.60 ± 2.40a
0.65 ± 0.06h
0.944 ± 0.000a
2.66 ± 0.04b

Çalıdere
34.55 ± 0.26bc
20.85 ± 5.02a
1.68 ± 0.02b
0.938 ± 0.001bc
2.87 ± 0.11ab

Kopuz
29.27 ± 0.43cd
18.85 ± 0.49a
1.08 ± 0.01ef
0.943 ± 0.002ab
2.64 ± 0.04b

Yaylapınar
39.59 ± 1.12ab
26.30 ± 0.14a
1.52 ± 0.10bc
0.931 ± 0.000de
3.25 ± 0.02a

Dağtarla
34.71 ± 0.66bc
23.00 ± 0.00a
1.27 ± 0.02de
0.937 ± 0.000cd
2.74 ± 0.11b

Bayburt city center
41.61 ± 1.88a
27.75 ± 6.01a
2.13 ± 0.02a
0.931 ± 0.001e
3.23 ± 0.04a

Different superscript letters show the differences between the samples ( significance level).

The ash content of Berberis fruits was determined to be between 0.65% and 2.13% (Table 2). Previous reports demonstrated the ash content of B. vulgaris samples between 0.65% and 3.44% [19, 21, 22] and 1.36 ± 0.07% for B. crataegina [20]. On the other hand, the data we obtained was parallel to that of Akbulut et al. [21] and Karabulut [20], but was lower than that of Demir [19], and was higher than that of Yildiz et al. [22]. It can be suggested that these differences in the amount of ash content may result from the growing conditions of the fruits. There was a significant level of difference () in terms of ash content among the fruit samples (Table 2). The pH value of the Berberis fruits was in the range of 2.44–3.25. In previous studies, the pH values of Berberis fruits were determined to be 5.5 by Demir [19], 3.35 by Akbulut et al. [21], between 3.13 and 4.43 by Ahmed et al. [23], 3.06 by Ardestani et al. [24], between 2.68 and 3.26 by Yildiz et al. [22], and between 2.59 and 3.2 by Okatan and Çolak [25]. And finally, Karabulut [20] determined the pH values as 2.85 ± 0.16 and 3.05 ± 0.01 in B. vulgaris and B. crataegina, respectively. Our results were in a similar range compared to the previous studies. The lowest pH value was determined in Berberis fruit grown in Aydıntepe as 2.44 and the highest was in Yaylapınar as 3.25.

The aw values of the Berberis fruits were in the range of 0.931–0.947. Karabulut [20] reported the aw value as 0.95 in B. vulgaris and 0.94 in B. crataegina which was higher compared to our findings. The lowest water activity value was obtained from the Berberis fruits collected from the central district and Yaylapınar village as 0.931, whereas the highest was obtained from the Aslandede village as 0.947 (Table 2).

The water-soluble dry matter content of the Berberis fruits was found to be between 18.10% and 27.75% (Table 2). For B. vulgaris samples, the water-soluble dry matter content was reported to be between 16.93 and 23% [7, 20, 22, 24–26], whereas for B. crataegina a water-soluble dry matter content of 29.5% was reported in the literature [20]. The lowest water-soluble dry matter content was detected in Berberis fruit grown in Aslandede village as 18.10%, whereas the highest value was found in Berberis fruit grown in the central district as 27.75% value. No statistical significant difference was found in water-soluble dry matter content of the Berberis fruits ().

3.2. Total Phenolic Content and Antioxidant Activity of Berberis Fruits

One of the main reasons to explore the technofunctional properties of wild fruits is that they might have important levels of antioxidant activity originating from the phenolic substances presenting in the fruits. In this respect, the total phenolic content of the Berberis fruits was determined as μg·GAE·mg·DM⁻¹ and the antioxidant capacity of these fruits was tested with β-carotene, DPPH •, and ABTS • + methodologies. Table 3 shows the total phenolic content and antioxidant characteristics of water and ethanol extracts of Berberis fruits. The total phenolic content of the samples was observed to be within the range of 148.0–448.3 μg·GAE·mg·DM⁻¹ with the lowest and highest levels observed in Bv-W-8 (water extract) and Bv-EtOH-5 (ethanol extract) samples, respectively (Table 3). Previous studies also revealed the phenolic content of Berberis fruits, and our findings were lower [7, 22, 26, 27] or higher [20] compared to different reports showing the importance of the origin of the samples that can be affected by the geographical conditions. We should also note that there was significant difference among the samples collected from different regions of Bayburt province ().

Table 3: Total phenolic content and antioxidant activities of Berberis fruits.

Extracts
Total phenolic content (−μg·GAE/mg·DM)
β-Carotene (%)
DPPH• (%)
ABTS•+ (%)

Bv-EtOH-1
316.0 ± 58.8abcd
73.64 ± 0.90efghı
26.70 ± 0.19de
42.53 ± 4.28ef

Bv-W-1
195.0 ± 38.2cd
67.78 ± 2.81hıj
26.88 ± 2.45de
86.01 ± 0.72ab

Bv-EtOH-2
334.7 ± 61.9abcd
88.77 ± 0.38ab
26.98 ± 0.19de
57.77 ± 3.84bcdef

Bv-W-2
163.4 ± 32.9d
70.25 ± 2.60ghıj
25.17 ± 2.50ef
76.52 ± 0.82abcde

Bv-EtOH-3
440.2 ± 79.9ab
79.50 ± 0.70cdef
26.53 ± 0.19de
48.44 ± 13.70def

Bv-W-3
337.1 ± 62.4abcd
69.02 ± 2.70hıj
27.92 ± 2.42bcde
83.53 ± 0.70abc

Bv-EtOH-4
341.1 ± 63.0abcd
82.42 ± 0.60bcd
27.35 ± 0.19cde
50.04 ± 4.67cdef

Bv-W-4
307.9 ± 57.4abcd
80.91 ± 1.66cde
29.34 ± 2.37bcde
83.10 ± 0.53abc

Bv-EtOH-5
448.3 ± 81.2a
92.19 ± 0.26a
33.46 ± 0.17abcd
34.3 ± 20.0f

Bv-W-5
355.8 ± 65.5abcd
72.73 ± 2.38fghı
27.77 ± 2.37bcde
80.40 ± 12.45abcd

Bv-EtOH-6
398.0 ± 72.7abc
89.26 ± 0.36ab
34.38 ± 0.17abc
38.0 ± 22.3f

Bv-W-6
396.3 ± 72.4abc
82.65 ± 1.51bcd
34.75 ± 2.18ab
81.98 ± 0.60abcd

Bv-EtOH-7
328.1 ± 81.4abcd
77.54 ± 0.77cdefg
27.26 ± 0.19cde
36.51 ± 9.21f

Bv-W-7
232.4 ± 44.6abcd
72.73 ± 2.38fghı
40.44 ± 1.99a
76.54 ± 0.41abcde

Bv-EtOH-8
334.7 ± 61.9abcd
84.87 ± 0.52abc
26.24 ± 0.19e
33.06 ± 11.17f

Bv-W-8
148.0 ± 30.3d
75.21 ± 2.16defgh
27.16 ± 2.44de
86.57 ± 4.85ab

Bc-EtOH-9
189.4 ± 37.3cd
67.78 ± 1.11hıj
15.98 ± 0.21g
76.28 ± 1.46abcde

Bc-W-9
191.0 ± 37.6cd
77.69 ± 1.94cdefg
13.60 ± 2.90g
92.85 ± 0.03a

Bc-EtOH-10
247.0 ± 47.1abcd
82.91 ± 0.58bcd
19.04 ± 0.21fg
75.10 ± 3.72abcde

Bc-W-10
211.3 ± 41.0bcd
66.78 ± 4.23ıj
17.30 ± 2.77g
91.35 ± 1.13ab

Bc-EtOH-11
170.7 ± 34.1cd
83.40 ± 0.57bc
11.92 ± 0.22g
48.14 ± 5.40def

Bc-W-11
202.4 ± 39.5cd
62.83 ± 3.25j
18.72 ± 2.73fg
91.21 ± 1.08ab

Different superscript letters show the differences between the samples within each row ( significance level).

The first methodology that was used for the determination of the antioxidant characteristics of Berberis fruits was β-carotene bleaching method. As can be seen in Table 3, the antioxidant levels of Berberis fruits were observed to be between 62.83% and 92.19%. The antioxidant capacity of the ethanol extracts was within the similar range compared to the BHA used as standard in β-carotene bleaching method (96.22% antioxidant activity). Our findings were similar to the previous observations as Motalleb et al. [27] determined the antioxidant activity of B. vulgaris fruits by β-carotene bleaching method as 73.62% in ethanol extract and 82.52% in water extract. Yildiz et al. [22] found 75.01–90.64% antioxidant activity in B. vulgaris, whereas Karabulut [20] found 87.35% and 90.50% antioxidant activity for B. vulgaris and B. crataegina, respectively. The lowest and the highest antioxidant activity with β-carotene bleaching method were observed in Bc-W-11 as 62.83% and in Bv-EtOH-5 as 92.19%, respectively (Table 3).

Another test used to determine the antioxidant activity of the Berberis fruits was DPPH radical scavenging activity test and the antioxidant level of the Berberis fruits was observed to be in the range of 11.92%–40.44% (Table 3). Previously, Motalleb et al. [27] determined the B. vulgaris DPPH • free radical cleaning activity as 82.52 ± 0.64% and 73.62 ± 1.87% for water and ethanol extracts, respectively. Karabulut [20] reported the antioxidant content as 15.65 mg ml⁻¹ in B. vulgaris and 6.30 IC₅₀ mg·ml⁻¹ in B. crataegina, while Gholizadeh-Moghadam et al. [28] found the highest antioxidant activity in B. vulgaris as 56.84%. The radical scavenging activity of Bc-EtOH-11 extract was the lowest with 11.92%, and the radical scavenging activity of Bv-W-7 extract was the highest with 40.44%.

Finally, we used ABTS•+ methods to determine the antioxidant characteristics of Berberis fruits (Table 3). Previously, the antioxidant capacity of B. vulgaris was tested and Özgen et al. [7] determined the ABTS•+ antioxidant capacity between 41.1 and 49.3 TE at mmol·L⁻¹. Yildiz et al. [22] expressed the ABTS value for Trolox equivalent mole per liter of juice between 53.2 and 56.10 mmol per L. Similar to the previous tests used in this study, ABTS•+ radical cleaning activity of water extracts was found to be higher compared to the ethanol extracts. The lowest and the highest ABTS•+ results were observed for sample Bv-EtOH-8 and sample Bc-W-9 with 33.06% and 92.85%, respectively.

3.3. Determination of Phenolic Profiles of Berberis Fruits by HPLC Analysis

As Berberis fruits showed high level of antioxidant capacity, we then performed HPLC analysis to determine the presence and the level of phenolic compounds within these fruits and the levels of gallic acid, 4-hydroxybenzoic acid, chlorogenic acid, vanillic acid, caffeic acid, syringic acid, p-coumaric acid, trans-ferulic acid, and sinapic acid were determined (Table 4). Similar to the antioxidant activity tests, the level of phenolic compounds in ethanol extracts of the fruit samples was higher compared to the water extracts. Chlorogenic acid and syringic acid have been found to be the most abundant phenolic compounds in Berberis fruit extracts. The presence of 4-hydroxybenzoic acid and p-coumaric acid could not be observed in the fruit extracts investigated. High concentrations of chlorogenic acid, syringic acid, gallic acid, sinapic acid, caffeic acid, vanillic acid, and trans-ferulic acid were observed (Table 4). It has been determined that syringic acid has high-level antioxidant activity [29]. Previously, Gündoğdu [17] determined chlorogenic acid as the dominant phenolic compound in B. vulgaris fruits which was similar to our findings. Gholizadeh-Moghadam et al. [28] reported that in the extracts of Berberis fruits, gallic acid and p-coumaric acid were the most commonly found phenolic compounds and the phenolic compounds and their levels were reported to be gallic acid (334.82 mg·L⁻¹), caffeic acid (51.78 mg·L⁻¹), chlorogenic acid (119.53 mg·L⁻¹), p-coumaric acid (257.09 mg·L⁻¹), cinnamic acid (0.57 mg/L), rutin (7.61 mg/L), apigenin (4.44 mg/L), and quercetin (37.20 mg/L) as the highest concentrations in the aforementioned study. Variability in the content of phenolic compounds and flavonoid concentrations in plant species may be related to genetic structure, environmental conditions (light, temperature, soil conditions, humidity, and fertilizer), harvest time, and storage conditions [29–31]. Overall, our findings revealed the rich phenolic content of the Berberis fruits.

Table 4: Phenolic component concentrations of alcohol and water extracts.

Extracts
Gallic acid (ppm)
Chlorogenic acid (ppm)
Vanillic acid (ppm)
Caffeic acid (ppm)
Syringic acid (ppm)
trans-Ferulic acid (ppm)
Sinapic acid (ppm)

Bv-EtOH-1
330.407
1990.482
3.599
79.235
450.493
—
187.628

Bv-W-1
248.962
1457.368
7.519
83.052
167.997
—
147.936

Bv-EtOH-2
270.764
2147.935
39.599
62.666
867.850
—
221.869

Bv-W-2
70.612
1527.302
7.649
57.785
161.276
—
138.455

Bv-EtOH-3
301.783
1820.423
3.308
61.259
429.763
—
153.159

Bv-W-3
76.907
1838.733
7.688
73.575
159.643
—
136.127

Bv-EtOH-4
330.031
1746.525
55.326
125.701
498.830
37.616
137.746

Bv-W-4
71.751
1938.942
60.915
83.891
133.377
—
207.935

Bv-EtOH-5
173.777
1619.128
52.789
134.749
559.397
26.400
149.360

Bv-W-5
242.706
1459.171
23.640
115.551
180.529
0.145
142.547

Bv-EtOH-6
299.670
1723.521
39.585
129.781
541.082
38.894
138.978

Bv-W-6
71.155
1510.845
28.114
121.391
189.415
8.881
143.345

Bv-EtOH-7
308.482
1678.213
4.657
79.176
—
3.140
146.024

Bv-W-7
237.531
1692.855
48.325
152.225
168.403
13.022
146.292

Bv-EtOH-8
507.050
1773.266
4.123
90.684
549.545
—
137.539

Bv-W-8
76.685
1357.626
6.049
78.679
177.098
—
139.624

Bc-EtOH-9
285.826
466.083
23.110
76.845
538.558
0.232
136.504

Bc-W-9
138.940
225.764
46.429
80.466
326.977
19.473
148.021

Bc-EtOH-10
275.804
869.295
68.742
77.577
472.667
30.090
142.288

Bc-W-10
200.513
767.036
4.007
68.073
204.618
14.682
137.678

Bc-EtOH-11
218.348
446.648
52.048
67.934
549.820
7.841
148.370

Bc-W-11
41.186
79.109
3.951
34.677
13.634
—
136.605

3.4. Antimicrobial Activity

There is an increasing trend to find new sources of antimicrobials and in this study, the water extracts of Berberis fruits were tested against five foodborne pathogenic bacteria. The antimicrobial activity was extract specific as only four extracts showed antimicrobial activity. Extract Bv-W-4 showed the highest level of antimicrobial activity observed against four pathogenic bacteria except E. coli in which none of the extracts showed antimicrobial activity (Table 5). Extract Bv-W-4 was more effective to S. typhimurium and S. aureus then Y. enterocolitica and B. cereus and to the latter pathogenic strain, only extract Bv-W-4 showed antimicrobial activity. Importantly, the only extract that showed antimicrobial activity to pathogenic bacteria from B. vulgaris was Bv-W-4 and the other three extracts that showed antimicrobial activity were from B. crataegina.

Table 5: Antimicrobial activities of Berberis fruit extracts against foodborne pathogens.

Extracts
Escherichia coli
Bacillus cereus
Salmonella typhimurium
Yersinia enterocolitica
Staphylococcus aureus

BvW1
−
−
−
−
−

Bv-W-2
−
−
−
−
−

Bv-W-3
−
−
−
−
−

Bv-W-4
−
+
++
+
++

Bv-W-5
−
−
−
−
−

Bv-W-6
−
−
−
−
−

Bv-W-7
−
−
−
−
−

Bv-W-8
−
−
−
−
−

Bc-W-9
−
−
+
+
++

Bc-W-10
−
−
−
−
+

Bc-W-11
−
−
+
+
++

The symbols + and ++ reveal the zone of inhibition as 1–7 mm and 8–15 mm diameter, respectively.

In this study, fruit extracts of B. vulgaris and B. crataegina were found to show antimicrobial activity against B. cereus, S. typhimurium, Y. enterocolitica, and S. aureus. Previously, Awan et al. [32] investigated the antimicrobial activity of Berberis calliobotrys, Berberis orthobotrys, and Berberis psedumbellata fruits and found that they showed antimicrobial activity against E. coli, Pseudomonas spp., and Bacillus cereus bacterial strains. Similar to this study, our finding also reveals the potential of the extracts of Berberis fruits as antimicrobials to be used for different purposes.

4. Conclusion

In this study, wild B. vulgaris and B. crataegina were collected from Bayburt province and their physicochemical characteristics, phenolic content, and antioxidant and antimicrobial properties were determined. The physicochemical characteristics of the Berberis fruits were affected by the collection location, suggesting the role of geographical conditions. The total phenolic content of the samples was observed to be within the range of 148.0–448.3 μg·GAE·mg·DM⁻¹. Both ethanol and water extracts of the fruits showed higher level of antioxidant activity tested by β-carotene, DPPH•, and ABTS•+ tests and the ethanol extracts showed higher level of antioxidant activity compared to the water extract. The phenolic profile of the Berberis fruits was determined by HPLC analysis, and chlorogenic acid and syringic acid were found to be the most abundant phenolic compounds in Berberis fruits. The antimicrobial activity of the water extracts of the Berberis fruits were tested against foodborne pathogens, and three extracts showed antimicrobial activity against three pathogenic bacteria. In summary, wild barberry B. vulgaris and B. crataegina have important potential for food industry and for other technological purposes as antioxidant compounds.

Data Availability

The data used to support the findings of this study are available from the corresponding author upon request.

Conflicts of Interest

The authors declare that there are no conflicts of interest regarding the publication of this paper.

Acknowledgments

This research was supported by Bayburt University through an internal grant.

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