Ethnopharmacology, Phytochemistry, and Pharmacological Properties of Thymus satureioides Coss.

Thymus satureioides Coss. (Lamiaceae) is a Moroccan medicinal plant locally known as “Azkouni” or “Zaitra.” It is widely used in traditional medicine to treat various ailments, including hypertension, diabetes, cold, fever, dermatological and circulatory disorders, immune problems, bronchitis, nociception, cooling, pharyngitis, cough, and influenza. The current review aims to critically summarize the literature on ethnopharmacological uses, chemical profile, and pharmacological investigations of T. satureioides in order to provide data support and scientific evidences for further investigations. Electronic databases such as Scopus, PubMed, Web of Science, SciFinder, ScienceDirect, Google Scholar, and Medline were used to gather data on T. satureioides. Chemical characterization of T. satureioides essential oils (EOs) and extracts allowed to identify a total of 139 bioactive compounds, mainly belonging to the terpenoids, phenolic acids, and flavonoids classes. T. satureioides especially its essential oils exhibited numerous biological activities such as antibacterial, antifungal, anti-inflammatory, antioxidant, antidiabetic, anticancer, antiparasitic, and hypolipedemic activities. In light of these findings, further studies to transmute the traditional application of T. satureioides into scientific-based information are strongly required. Additional in vivo pharmacological studies are recommended to validate the results of the in vitro studies. Moreover, comprehensive preclinical and clinical trials on the pharmacological mechanisms of action of this plant and its bioactive compounds on molecular targets should be performed. Finally, more efforts must be focused on toxicological assessments and pharmacokinetic studies, in order to ensure the safety and the efficiency of T. satureioides.


Introduction
ymus satureioides Coss. is a perennial shrub (10-60 cm in height) belonging to the Lamiaceae family and the genus ymus [1,2]. T. satureioides is an endemic Moroccan medicinal plant locally known as "Azkuni" or "Zaitra" [3]. is species is widely distributed in the arid and semiarid habitats of the Moroccan High Atlas and Anti-Atlas [1,4].

3.3.
Phytochemistry. Phytochemical screening of T. satureioides EOs and extracts revealed the presence of a total of 139 bioactive compounds, which can be grouped into three main chemical classes, including terpenoids, phenolic acids, and flavonoids ( Table 2).

Phenolic Compounds.
anks to their phenolic group, the phenolic compounds such as phenolic acids, flavonoids, tocopherols, and tannins are considered as an important group of bioactive compounds that are responsible for a wide range of biological properties such as antimicrobial [51,52], antioxidant [53] anticancer [54], and litholytic activities [55]. Besides their pharmacological potential, the phenolic compounds, particularly flavonoids, are involved in many physiological processes; they are included in the regulation and protection of vascular plants against several biotic and abiotic stresses [56][57][58].
ere are few studies investigating the chemical composition of T. satureioides extracts. In fact, the phenolic profile of T. satureioides remains not well identified.  Evidence-Based Complementary and Alternative Medicine Khouya et al. [24] have examined the phenolic composition of the T. satureioides aqueous extracts and reported that they contain high levels of phenolic compounds, which are represented by rosmarinic acid as major phenolic acid and luteolin-7-glycoside and hesperetin as major flavonoids. Another study showed that T. satureioides aqueous extracts were rich in total polyphenols (456.73 ± 6.94 mg caffeic acid equivalent/g of dry plant) and in flavonoid group (172.79 ± 2.12 mg rutin equivalent/g of dry plant) with rosmarinic acid, hesperetin, and luteolin-7-glucoside as major phenolic compounds [13].
In addition, the chemical composition of the methanol extracts of T. satureioides analyzed by a combination of chromatographic tools (reverse-phase HPLC and 1 H NMR analyses) revealed the presence of flavonoids as the main constituents with five essential compounds: luteolin-3′-O-glucuronide, luteolin-7-O-glucoside, eriodictyol-7-O-glucoside, aglycone luteolin, and thymonin [14]. However, other molecules such as ursolic acid and oleanolic acids were identified in the chloroform extract of T. satureioides [14].
e qualitative phytochemical analysis of T. satureioides extracts (hydromethanol, chloroform, ethyl acetate, and Gastrointestinal complaints, influenza, colds, fever, headaches, affections of the annex glands of the digestive tract, respiratory problems, and menstruation pain in women [5] Agadir-Ida-Ou-Tanane Province (Southwest  Morocco) Whole plant, flowers, leaves, and stems Infusion Respiratory, digestive, skin, circulatory, genital, nervous, visual, and urinary problems [12] Beni Mellal (Morocco) Leaves Decoction and infusion Diabetes [28] High Atlas mountains (Morocco) Whole plant Powder Gastrointestinal ailments (stomach ache and intestinal trouble) and respiratory disorders such as colds and coughs [29] Haouz-Rhamna region (Morocco) Leaves Decoction and infusion Diabetes [9] Er-Rich region (High Atlas of Morocco) Aerial parts Decoction and infusion Gastric disorders, chills, cold, fever, headaches, digestive infections, and pain, and it is also used as an antispasmodic agent [11] Er-Rich region Evidence-Based Complementary and Alternative Medicine  Evidence-Based Complementary and Alternative Medicine butanol extracts) enabled to detect the presence of flavonoids, catechols, gallic tannins, and anthraquinones [60]. Moreover, the quantitative HPLC analysis of crude and organic extracts of T. satureioides aerial parts showed the presence of phenolic acids (caffeic acid and rosmarinic acid) and the flavonoids quercetin and hesperetin in crud and methanolic extracts, whereas rosmarinic acid, hyperoside, quercetin, and hesperetin were detected in ethyl acetate extracts [39]. Interestingly, Kouar et al. [38] have determined the phytochemical profile of alcoholic extract of T. satureioides leaves, using the electrocoagulation and solvent extraction assays, and detected the presence of saponins, sterols, triterpene, tannins, and flavone aglycones. e quantitative analysis showed that T. satureioides alcoholic extract contains high levels of total polyphenols (70.2 ± 0.4 mg of gallic acid equivalents/g extract) and total flavonoids (52.7 ± 0.01 mg of quercetin equivalents/g extract).

Volatile Compounds.
Numerous studies have investigated and characterized the chemical composition of T. satureioides EOs, particularly from the aerial parts.
e chemical analysis showed that T. satureioides EOs are mainly composed of borneol, thymol, carvacrol, camphene, α-pinene, α-terpineol, p-cymene, and linalool ( Figure 4). e percentages and the nature of these volatile compounds vary noticeably depending on several intrinsic and extrinsic factors of the plant, including geographical origin, phenological stage, genotype, plant's part used, and storage and extraction conditions [61,62].
e studies carried out on T. satureioides from the High Atlas of Morocco indicated that carvacrol (26.5%) and borneol (20.1%) are the main compounds of its EOs, while thymol was not identified [15,49].

Evidence-Based Complementary and Alternative Medicine 7
Another study revealed the presence of 68 volatile compounds representing 93.3% of T. satureioides aerial parts' total EOs using capillary gas chromatography and gas chromatography coupled to mass spectrometry (GC-MS) [40]. ese volatile compounds mainly belong to the monoterpenoides class (monoterpene hydrocarbons, oxygenated monoterpenes, and phenolic monoterpenes) such as borneol, carvacrol, thymol, camphene, linalool, and camphor.

Pharmacological Properties.
Numerous pharmacological investigations have shown that T. satureioides essential oils and extracts obtained from different plant parts possess various biological activities, including antibacterial, antioxidant, antifungal, antiparasitic, anticancer, antidiabetic, and anti-inflammatory effects ( Figure 5).

Antibacterial Activity.
e antibacterial activity of T. satureioides EOs and extracts, against a panel of bacterial strains, including Gram-positive and Gram-negative bacteria, was reported in the literature [16,63,64].
Indeed, the EOs obtained from different parts of T. satureioides were evaluated against several pathogenic bacteria known by their drug multiresistance, including Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii, and methicillin-resistant Staphylococcus aureus (MRSA). Table 3 summarizes the published works that investigated the antibacterial activities of T. satureioides. It lists the parts used, the tested extracts, the methods used, the tested strains, and the main results obtained.
Ou-Yahia et al. [67] assessed the antibacterial effect of the T. satureioides aerial part EOs against E. coli, Bacillus cereus, P. aeruginosa, Salmonella typhimurium, S. aureus, Micrococcus luteus, and Bacillus subtilis and showed a variable antibacterial activity of the tested EOs. e highest activity was observed against B. cereus and S. aureus with MIC values of 0.015% and 0.03%, respectively, while P. aeruginosa was the most resistant bacterium with a MIC value of 1%.
In another study, testing of the bacteriostatic and bactericidal effects of EOs of T. satureioides leaves and flowering top on E. coli, S. aureus, A. baumannii, B. cereus, and Enterobacter cloacae revealed a significant antibacterial activity (inhibition zone diameters (V): 16 mm < V < 30.7 mm for leaves EOs; 22 mm < V < 45 mm for flowering top EOs) and a bacteriostatic effect against all tested strains except B. cereus [71].
Mekkaoui et al. [70] tested in vitro the antimicrobial effect of EOs of T. satureioides harvested at two different phenological stages (flowering and postflowering) against three pathogenic bacteria responsible for foodborne disease in Morocco (E. coli, B. subtilis, and Mycobacterium smegmatis). ey showed that EOs obtained after the flowering stage were more active against the studied strains than those obtained in the flowering stage. In fact, the highest activity was shown against M. smegmatis followed by B. subtilis, while the weakest activity was noticed against E. coli [70]. In the same context, Oussalah et al. [72] evaluated the antibacterial potential of the T. satureioides flower EOs against four pathogenic bacteria including two Gram-positive bacteria: S. aureus and Listeria monocytogenes (2812 1/2a), and two Gram-negative bacteria: E. coli O157:H7 and S. typhimurium (SL 1344), using the broth microdilution method. e results indicated that S. aureus was the most sensitive bacterium with MIC � 0.05% (v/v) followed by E. coli O157:H7 and S. typhimurium (MIC � 0.2% (v/v)), while L. monocytogenes was the least sensitive bacteria to the tested EOs with MIC � 0.4% (v/v).
More interestingly, Amrouche et al. [18] investigated both in vitro and in a food system the antibacterial activity of T. satureioides EOs, extracted from the whole plant, against foodborne bacteria (E. coli, S. aureus, and B. cereus). e paper disc diffusion and broth microdilution methods were used for the in vitro test and the beef minced meat was used as food model. ereby, the addition of T. satureioides EOs to inoculated beef minced meat decreased the tested strain population after 4 days of storage. Moreover, in vitro investigations indicated that B. cereus was the most sensitive bacteria (V � 19 mm and MIC � 1.1%), followed by S. aureus (V �16 mm, MIC � 1.1%) and then E. coli (V � 14.25 mm, MIC � 1.25%) [18].
El Abdouni Khayari et al. [ [15]. e highest activity was found for M. luteus (V � 49.17 ± 1.15 mm for wild TS, V � 29.67 ± 1.15 mm for cultivated TS), while the weakest activity was noticed against S. aureus (V � 30.33 ± 0.58 mm for wild TS, V � 47.83 ± 1.32 mm for cultivated TS). Moreover, a considerable activity was also noted against Gram-negative bacteria with inhibition zone diameters ranging from 19.00 ± 0.10 to 23.00 ± 1.00 mm. e microdilution approach revealed a promising antibacterial effect of the tested EOs with MIC values ranging from 0.45 to 1.78 μg/ mL [15].
is remarkable antibacterial effect of the T. satureioides EOs is concordant with the results of an earlier investigation, which indicated that T. satureioides E.Os inhibit the growth of a panel of microorganisms (65 Gram-positive and Gram-negative bacterial strains), among which Aeromonas hydrophila, Vibrio cholera, and Stenotrophomonas maltophilia were the most sensitive bacteria with respective MIC values of 0.14 ± 0.4% (v/v), 0.14 ± 0.0% (v/v), and 0.16 ± 0.0% (v/v) [74].
Recently, Meziani et al. [63] studied the antimicrobial effect of EOs and aqueous and methanolic extract from thyme leaves against Microbacterium testaceum and Serratia marcescens endophytic to date palm by using different approaches including quantitative and qualitative methods. ey demonstrated that the EOs were more active against both reported bacteria than aqueous and methanolic extracts (Vs < 15 mm). us, these EOs have a great inhibition power against M. testaceum (V > 20 mm, MIC � 0.025%, MBC � 0.033%) and a good effect against S. marcescens (15 mm < V < 19 mm, MIC � 0.033%, MBC � 0.05%) [63].

Antioxidant Activity.
e use of T. satureioides as a food preservative and against several pathologic disorders in Moroccan folk medicine encouraged the research teams to study the antioxidant potential of this plant species. In fact, several works reported the antioxidant activity of T. satureioides EOs as well as its extracts obtained from different plant parts (aerial parts, flowering top, and leaves) using different methods such as 2,2′-azino-bis 3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical scavenging, ferric reducing power, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, thiobarbituric acid reactive substances (TBARS), 2,2-azobis 2-amidinopropane dihydrochloride (APPH), and β-carotene/linoleic acid bleaching assays [13,21,39,75]. All published works that studied the antioxidant activity of T. satureioides EOs and extracts have been listed and summarized in Table 4.

Evidence-Based Complementary and Alternative Medicine
In a recent study, Hmidani et al. [76] measured the capacity of aqueous extract of T. satureioides to scavenge the generated radical ABTS+•, using ABTS assay, and showed significant scavenging activity of this extract (IC 50ABTS � 14.65 ± 0.36 μg/ml) compared to ascorbic acid as standard (IC 50 � 1.96 ± 0.1 μg/ml). ese findings support those obtained by Khouya et al. [24], which showed a considerable antioxidant activity of the T. satureioides aerial part aqueous extract. Indeed, the tested aqueous extracts displayed potent scavenging activity against DPPH radical with an IC 50 value equal to 0.44 ± 0.01 mg/mL TAE and a higher reducing power of ferric complex (40.14 ± 4.55 mmol Trolox/gTAE) than the Trolox used as positive control (44.33 ± 7.55 mmol Trolox/gTAE). Moreover, the aqueous extracts of T. satureioides exerted a potent protective potential against hemolysis of erythrocytes according to APPH Evidence-Based Complementary and Alternative Medicine test results [24]. ese considerable antioxidant effects of the aqueous extracts were attributed to their high phenolic content [24].

Antifungal Activity.
e antifungal activity of T. satureioides, especially its essential oils against several pathogenic fungal, has been reported in the literature [19,50,78,79].
Asdadi et al. [19] studied the anticandidal activity of T. satureioides EOs (10 μl) against nosocomial fluconazoleresistant strains (Candida dubliniensis, C. albicans, C. glabrata, and C. krusei) using disc diffusion and microdilution methods, with fluconazole (10 μl) and amphotericin B (10 μl) as positive controls. According to this study, C. dubliniensis was the most sensitive strain to the tested EOs (V � 85 mm), followed by C. krusei (V � 67 mm), while C. albicans and C. glabrata were the least sensitive fungal strains with V of 53 mm and 49 mm, respectively. e microdilution assays showed an interesting anticandidal effect with minimal fungicidal concentration (MFC) values ranging between 0.3300 mg/mL and 0.9062 mg/ml [19].
In addition, El Bouzidi et al. [15] assessed the anticandidal activity of T. satureioides EOs obtained from aerial parts against four candida species, including C. albicans, C. glabrata, C. parapsilosis, and C. krusei using disc diffusion and microdilution assays, and fluconazol (40 μl) as reference. e findings of this study showed that all tested strains were more sensitive to the tested EOs (37.67 ± 1.53 mm < V < 42.00 ± 1.00 mm) than to the synthetic fungicide (fluconazol) used as a positive control (26.50 ± 0.50 mm < V < 29.83 ± 1.15 mm).
In the same context, Rahmouni et al. [42] reported fungicide effect of T. satureioides EOs and their major components (thymol, α-terpineol, carvacrol, and borneol) against a phytopathogenic fungus responsible for fusarium wilt on date palm in Morocco, named Fusarium oxysporum f. sp. Albedinis.
e results of this study showed that these EOs as well as their major compounds inhibited noticeably the mycelia growth of Fusarium oxysporum f. sp. Albedinis in a concentration-dependent manner.
Recently, El-Bakkal et al. [21] tested the antifungal effect of the EOs of T. satureioides aerial parts against Botrytis cinerea, P. digitatum, and Verticillium dahliae using disc diffusion method and fluconazol (40 μg/disc) as standard antifungal drug. eir results showed a promising antifungal effect, of the studied EOs, against the three tested strains, with inhibition zone diameters ranging from 31.50 ± 1.32 mm to 36.27 ± 1.15 mm compared to fluconazol (25.50 ± 0.50 < V < 28.00 ± 0.50).

Anti-Inflammatory Activity.
Inflammation is a complex biological process that maintains homeostasis of the organism in response to multiple injuries such as infection, trauma, or immune reaction. It is characterized by pain, heat, redness, and swelling [80].
Inflammation is related to the occurrence of several human pathologies, including heart diseases, Alzheimer's disease, and cancer [81][82][83]. e mechanisms of the antiinflammatory response involve various mediators such as phospholipase A2 activation, cytokines, chemokines, reactive oxygen species (ROS) generation, macrophages and mast cells, platelet-activating factor, and nitric oxide (NO) [83].
Khouya et al. [39] have evaluated in vivo the anti-inflammatory activity of T. satureioides crude extracts and fractions (dichloromethane, ethyl acetate, methanol, and aqueous) using croton-oil-induced ear oedema and carrageenan-induced paw oedema in mice and rats. e results of this study showed that topical applications of the dichloromethane and ethyl acetate fractions (1 mg/ear) reduced significantly ear oedema volume of 31.60% and 27.16%, respectively, after 4 h of treatment. e crude extracts exhibited the greatest activity, and its tropical application decreased significantly ear oedema (29.67%) 8 h after treatment. However, the methanol and aqueous fractions did not decrease ear oedema. Moreover, the results of carrageenan oedema assay showed that the ethyl acetate and methanol fractions (60 mg/kg) reduced significantly oedema induced by carrageenan during the first phase (16.40 ± 0.33% and 14.51 ± 1.40%, respectively) [39]. is study confirmed results obtained by the same authors, indicating that aqueous extracts of T. satureioides exhibited a remarkable anti-inflammatory effect in carrageenan-induced rats paw edema and in croton oil-induced mice ear edema [24]. In another previous study, Ismaili et al. [14] investigated the in vivo topical anti-inflammatory effect of methanol and chloroform extracts of T. satureioides leaves, using the croton oil ear test in mice, and showed that chloroform extract induced significant edema inhibition (at a inhibition dose ID 50 of 282 μg·cm −2 ), only three times lower than that of the standard conventional drug indomethacin used as positive control (ID50 � 93 μg·cm −2 ), while the methanolic extract did not show any topical anti-inflammatory activity.  [25].

Antiparasitic Effect. T. satureioides
Another study conducted by Avato et al. [26] showed that T. satureioides EOs exhibit a promising nematicidal activity against Meloidogyne incognita juveniles (mortality rate of 10.6 ± 0.7%) and adults of Pratylenchus vulnus (100 ± 0.0%) and Xiphinema index (14.9 ± 0.7%) and that, after 48 h, this effect was dose-dependent. e acaricidal activity of T. satureioides EOs was also reported in the literature. Ramzi et al. [85] studied the effect of the EOs of T. satureioides aerial parts against adults of Varroa destructor (Acari: Varroidae) and indicated an interesting mortality rate of 50% after 24 h and 80% after 48 h. Additionally, T. satureioides EO was shown to destroy completely the wheat pest Sitophilus oryzae (coleopters) at a concentration of 2.4 × 10 −2 μl/cm 3 after 24 h [86].
3.4.6. Other Pharmacological Properties. T. satureioides was also reported to exhibit other pharmacological properties such as anticancer, antidiabetic, and hypolipidemic effects.
Kabbaoui et al. [2] investigated the antidiabetic effect of T. satureioides aqueous extracts obtained from the aerial parts on streptozotocin-(STZ-) induced diabetic rats via the administration of an oral concentration of 500 mg/kg. As a result, T. satureioides aqueous extracts decreased significantly blood glucose levels and improved body weight and glucose tolerance in STZ-diabetic rats.

Conclusion and Perspectives
is scientific review reports the ethnomedicinal uses, chemical profile, and pharmacological properties of an endemic Moroccan medicinal plant: T. satureioides. is plant is widely used in Moroccan traditional medicine to treat several diseases such as hypertension, diabetes, skin ailments, and bronchitis.
Indeed, several investigations have demonstrated that T. satureioides exhibits numerous biological activities, including antibacterial, antifungal, antioxidant, anti-inflammatory, anticancer, antidiabetic, and antiparasitic activities. ese pharmacological effects have proven the traditional uses of T. satureioides. However, the evidence supporting the traditional practices such as skin disorders, hypertension, influenza, and visual ailments of modern pharmacology is still limited. In this regard, we invite research groups to conduct further studies on the antiviral, antileishmanial, and hypotensive effects of T. satureioides. Furthermore, the pharmacological mechanisms of action, of this plant, on molecular targets need to be explored using current experimental assessments such as network pharmacology, proteomic, and pharmacokinetic. Additionally, an appropriate pharmacological approach should be considered for providing comprehensive pharmacological information for T. satureioides. Moreover, T. satureioides have shown interesting biological effects against some related oxidative stress such as inflammation and cancer. Accordingly, extensive clinical studies should be carried out to determine pharmacodynamic and pharmacokinetic parameters in order to develop drug from T. satureioides. e phytochemical analysis using different chromatographic tools such as GC-MS and HPLC revealed the presence of a plethora of bioactive compounds mainly belonging to the terpenoids class in the essential oils of T. satureioides. is chemical diversity varied depending on plant's part used, season's harvest, plant's origin, as well as Evidence-Based Complementary and Alternative Medicine extraction and storage conditions. However, although numerous bioactive compounds have been isolated and identified from T. satureioides essential oils, few pure components have been assessed for their pharmacological effects. Furthermore, few studies have investigated the phenolic content of T. satureioides extracts. erefore, further efforts should be focused on such area in order to determine in detail the phenolic profile of this species using different extraction solvents and the current spectroscopic tools such as HPLC-DAD, infrared (IR), and 1 H NMR technique.
Finally, the acute, subacute, and subchronic toxicity tests are strongly required to verify the innocuity and the safety of this plant.

Data Availability
All data analyzed during this investigation are available from the corresponding author.