Untargeted Phytochemical Profiling, Antioxidant, and Antimicrobial Activities of a Tunisian Capsicum annuum Cultivar.

Peppers are among the spices possessing a wide plethora of biological properties due to their excellent supply of health-related metabolites. Capsicum annuum L. (Solanaceae) is cultivated throughout Tunisia, and there is a shortage of information on the identification of the secondary metabolites in the seeds of this species as well as on their biological activities. In the present work, we intended to undertake a chemical characterization of the bioactive compounds from the hydro-methanolic seed extract of C. annuum as well as an evaluation of its broad spectrum of antimicrobial and antioxidant activities. The chemical profile was evaluated by RP-HPLC-DAD-QTOF-MS/MS, whereas the total phenol and flavonoid content, antioxidant, and antimicrobial activities were determined in in vitro assays. In this work, 45 compounds belonging to various phytochemical classes, such as organic acids (2), phenolic compounds (4 phenolic acids and 5 flavonoids), capsaicinoids (3), capsianosides (5), fatty acids (13), amino acids (1), sphingolipids (10), and steroids (2) were identified in the hydro-methanolic seed extract of C. annuum. The phenolic and flavonoid content (193.7 mg GAE/g DW and 25.1 mg QE/g DW, respectively) of the C. annuum extract correlated with the high antiradical activity (IC50 = 45.0 µg/mL), reducing power (EC50 = 61.3 µg/mL) and chelating power (IC50 = 79.0 µg/mL) activities. The hydro-methanolic seed extract showed an important antimicrobial activity against seven bacterial and four fungal strains. In fact, the inhibition zones (IZs) for bacteria ranged from 9.00 ± 1.00 mm to 12.00 ± 0.00 mm; for fungi, the IZs ranged from 12.66 ± 0.57 mm to 13.66 ± 0.57 mm. The minimal inhibition concentration and minimal bactericidal concentration values showed that the extract was more effective against fungi than bacteria.

Metabolic impairments and tissue disorders in alloxan-induced diabetic rats are alleviated by Salvia officinalis L. essential oil.

The current research explored for the first time the effect of Salvia officinalis L. (Sage) essential oil (EO) on Alloxan-induced diabetes in male Wistar rats. Sage EO was extracted by a Clevenger apparatus and analyzed by GC-FID and GC-MS. The most important chemical families identified in this oil were oxygenated monoterpenes (56.32%), hydrocarbon monoterpenes (15.00%) and hydrocarbon sesquiterpenes (14.70%). All treatments were administered orally. In vitro investigation showed that the EO had α-amylase and lipase inhibitory activities with IC50 = 38 µg/mL and IC50 = 52 µg/mL, respectively. In vivo experiments highlighted that the activities of serum α-amylase and lipase were reduced by 46.6% and 32.1%, respectively. Sage EO reduced glycemia by 60% and the level of glycogen stored in the liver by 43.7%. Treatments of diabetes with Sage EO significantly protected the liver function by lowering serum AST (35%), ALT (79%) and LDH (43%) activities. Furthermore, Sage EO was efficient to preserve the kidney function in diabetes by reverting back serum creatinine (47%) and UA (62.5%) concentrations to control values. The obtained results altogether evidenced that Sage EO had hypoglycemic and anti-obesity effects and could be a valuable complement in future diabetes therapy.

The cruciferous Diplotaxis simplex: Phytochemistry analysis and its protective effect on liver and kidney toxicities, and lipid profile disorders in alloxan-induced diabetic rats.

BACKGROUND: Type 2 diabetes mellitus is a prevalent systemic disease affecting an important proportion of the population worldwide. It has been suggested that excessive reactive oxygen species generation and therefore development of an oxidative stress status is a key factor leading to diabetic complications. Accordingly, it seems that medicinal plants can offer a wide range of new antidiabetic drugs. Diplotaxis simplex (Viv.) Spreng. (Brassicaceae) is an edible plant largely distributed in the Mediterranean region. D. simplex flowers display important in vitro antioxidant potential and inhibitory activity of the α-glucosidase, a key enzyme linked to type 2 diabetes mellitus. In this paper, the antihyperglycemic potential of D. simplex flowers on diabetic rats were investigated. METHODS: Bioactive substances were determined by liquid chromatography-high resolution electrospray ionization mass spectrometry (LC-HRESIMS) analysis. Animals were divided into four groups of six rats each: a normal control group, a diabetic control group, a diabetic group receiving flowers extract (200 mg/kg body mass) and a diabetic group receiving acarbose (10 mg/kg body mass) as standard drug. RESULTS: Many glycosides of rhamnetin, isorhamnetin, quercetin and kaempferol compounds were identified in the ethanolic flowers extract. Alloxan induced hyperglycemia, manifested by a significant (p < 0.05) increase in the blood glucose level as well as in serum α-amylase activity. Furthermore, diabetic rats exhibited oxidative stress, as evidenced by a decrease in antioxidant enzymes activities and an increase in lipid peroxidation level of the pancreas, liver and kidneys. Interestingly, the oral administration of D. simplex flowers extract during 30 days restored the glycemia, α-amylase activity, serum lipid profile and antioxidant enzymes. Moreover, the flowers extract exhibited a renal protective role by decreasing the urea and creatinine levels in diabetic rats serum. CONCLUSIONS: D. simplex flowers contained bioactive compounds that possess important antioxidant and hypoglycemic properties and protected pancreas, liver and kidneys against hyperglycemia damage.

Antioxidant and wound healing activity of Lavandula aspic L. ointment.

Lavandula aspic L. is a strongly aromatic shrub plant of the Lamiaceae family and traditionally used in herbal medicine for the treatment of several skin disorders, including wounds, burns, and ulcers. The present study aimed to investigate the composition and in vitro antioxidant activity of lavender essential oil. In addition, it aimed to evaluate the excision wound healing activity and antioxidant property of a Lavandula aspic L. essential oil formulated in ointment using a rat model. The rats were divided into five groups of six animals each. The test groups were topically treated with the vehicle, lavender ointment (4%) and a reference drug, while the control group was left untreated. Wound healing efficiency was determined by monitoring morphological and biochemical parameters and skin histological analysis. Wound contraction and protein synthesis were also determined. Antioxidant activity was assessed by the determination of MDA rates and antioxidant enzymes (GPx, catalase and superoxide dismutase). The treatment with lavender ointment was noted to significantly enhance wound contraction rate (98%) and protein synthesis. Overall, the results provided strong support for the effective wound healing activity of lavender ointment, making it a promising candidate for future application as a therapeutic agent in tissue repairing processes associated with skin injuries.

Antibiofilm formation and anti-adhesive property of three mediterranean essential oils against a foodborne pathogen Salmonella strain.

Plant extracts, and their essential oils (EOs) are rich in a wide variety of secondary metabolites with antimicrobial properties. Our aim was to determine the bioactive compound in three mediterranean essential oils belonging to Lamiaceae family, Satureja montana L., Thymus vulgaris L. and Rosmarinus officinalis L., and to assess their antimicrobial, antibiofilm and anti-adhesive potentials against a foodborne pathogen Salmonella strain. The antibacterial activity of EOs and its biofilm inhibition potencies were investigated on 2 reference strains Salmonella typhimurium and 12 Salmonella spp. isolated from food. Biofilm inhibition were assessed using the 2, 3-bis [2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT) reduction assay. The analytical data indicated that various monoterpene hydrocarbons and phenolic monoterpenes constitute the major components of the oils, but their concentrations varied greatly among the oils examined. Our results showed that S. montana L. and T. vulgaris L. essential oils possess remarkable anti biofilm, anti-adhesive and bactericidal properties, compared to R. officinalis EO. There is an indication that Rosmary EO might inhibit biofilm formation at higher concentrations. Therefore, the witer savory and thyme EOs represent a source of natural compounds that exhibit potentials for use in food systems to prevent the growth of foodborne bacteria and extend the shelf life of the processed food.

Diplotaxis simplex suppresses postprandial hyperglycemia in mice by inhibiting key-enzymes linked to type 2 diabetes

Abstract Nutritional properties of Diplotaxis simplex Spreng., Brassicaceae, an edible wild cruciferous largely distributed in North Africa, were investigated. Potassium (3690–3780 mg/100 g) and calcium (900–1170 mg/100 g) were the most concentrated minerals. Linoleinic acid was found to be the main fatty acid (25.4–27.7%), followed by palmitic acid (13.2–15.3%). Moreover, lipidic fraction of leaves was characterized by a relatively high rate of ethyl linoleate (14.4%) and phytol (17.6%). Ethyl acetate extract of D. simplex flowers showed concentration-dependent α-amylase (IC50 3.46 mg/ml) and α-glucosidase (IC50 0.046 mg/ml) inhibitory activities. The positive in vitro enzymes inhibition was confirmed by a maltose tolerance test, which showed that treatment with flowers extract significantly inhibited the rise in blood glucose levels of maltose-loaded mice comparable to the standard antihyperglycemic agent acarbose. From these results, it may be concluded that D. simplex flowers can be used effectively as a safer alternative therapy to control postprandial hyperglycemia.

Essential oil variation in wild populations of Artemisia saharae (Asteraceae) from Tunisia: chemical composition, antibacterial and antioxidant properties.

BACKGROUND: Artemisia saharae Pomel is a new taxon of Artemisia herba-alba Asso (Asteraceae) which is endemic to Tunisia and Algeria. This shrub, commonly known as white wormwood or desert wormwood, is largely used in folk medicine and as a culinary herb. The bulks aromatic plants come from wild populations whose essential oils compositions as well as their biological properties are severely affected by several factors such as geographic conditions. Therefore, the aim of the present work is to provide more information about the influence of altitude variation on the essential oil composition, antimicrobial and antioxidant properties of Artemisia saharae growing wild in the same geographical area. RESULTS: Essential oils were extracted by hydrodistillation of leaves and flowers of the plant collected from seven different altitudes of the Baten Zamour region (southwest of Tunisia). The highest essential oil yields (2.70-2.80%) were obtained for populations of high altitudes. Seventy-five compounds, representing 92.78 to 96.95% of the total essential oils, were separated and identified. Essential oils were characterized by very high percentage of oxygenated monoterpenes (52.1-72.6%) which constituted the predominant class. From the analyzed populations, the major compounds (>7%) were α-thujone, ß-thujone, chrysanthenone, camphor, chrysanthenyl acetate, and sabinyl acetate. Sabinyl acetate which was detected in some populations at relatively high percentages (7.7-10.8%) seems to be characteristic to Southern Tunisian A. saharae. The studied essential oil showed a chemical diversity depending on the population altitude as revealed by linear discriminant and cluster analyses. CONCLUSIONS: Three population groups associated with altitudinal levels were distinguished. It is worthy to note that the most discriminating compounds of chemical groups were the minor ones. Despite the high variation of essential oil compositions, the high altitude population did not affect severely the antibacterial activity against the most tested strains. Altitude seems to be an important factor influencing the yield and the chemical profile of Artemisia saharae essential oils. Knowledge of the chemical composition of essential oils in relation to environmental factors is a very important quality criterion for their marketing and contributes to their valorization as functional ingredient in food technology.

Evaluation of Antioxidant Status of Two Limoniastrum Species Growing Wild in Tunisian Salty Lands.

We aim to highlight the differential antioxidant status of Limoniastrum guyonianum and Limoniastrum monopetalum in relation to their respective chemical and location characteristics. Metabolite analysis revealed similar contents in phenolic, flavonoïds, sugars and chlorophyll in the two species' leaves. Higher amounts of proline (Pro), carotenoïds (Carot), sodium (Na) and potassium (K) were measured in L. monopetalum leaves relative to L. guyonianum ones. While the two Limoniastrum species have similar free radical DPPH (2,2-diphenyl-1-picrylhydrazyl) scavenging activity, L. guyonianum showed more than two-fold higher ferrous ions chelating activity relative to L. monopetalum. However, highest reducing power activity was observed in L. monopetalum. Thiobarbituric acid-reactive substances (TBARS) determination indicated that L. monopetalum behave better lipid membrane integrity relative to L. guyonianum. These findings suggested that the lesser stressful state of L. monopetalum was related to higher metabolites accumulation and reducing capacity compared to L. guyonianum.

Variation of chemical composition of essential oils in wild populations of Thymus algeriensis Boiss. et Reut., a North African endemic species.

UNLABELLED: ABSBACKGROUND: Thymus algeriensis is an endemic aromatic plant to Tunisia largely used in folk medicine and as a culinary herb. The bulks aromatic plants come from wild populations whose essential oils compositions as well as their biological properties are severely affected by the geographical location and the phase of the plant development. Therefore, the aim of the present work is to provide more information on the variation of essential oil composition of T. algeriensis collected during the vegetative and the flowering phases and from eight different geographical regions. Besides, influence of population location and phenological stage on yield and metal chelating activity of essential oils is also assessed. METHODS: The essential oil composition of Thymus algeriensis was determined mainly by GC/FID and GC/MS. The chemical differentiation among populations performed on all compounds was assessed by linear discriminate analysis and cluster analysis based on Euclidean distance. RESULTS: A total of 71 compounds, representing 88.99 to 99.76% of the total oil, were identified. A significant effect of the population location on the chemical composition variability of T. algeriensis oil was observed. Only 18 out of 71 compounds showed a statistically significant variation among population locations and phenological stages. Chemical differentiation among populations was high. Minor compounds play an important role to distinguish between chemical groups. Five chemotypes according to the major compounds have been distinguished. Chemotypes distribution is linked to the population location and not to bioclimate, indicating that local selective environmental factors acted on the chemotype diversity. CONCLUSIONS: The major compounds at the species level were α-pinene (7.41-13.94%), 1,8-cineole (7.55-22.07%), cis-sabinene hydrate (0.10-12.95%), camphor (6.8-19.93%), 4-terpineol (1.55-11.86%), terpenyl acetate (0-14.92%) and viridiflorol (0-11.49%). Based on major compounds, the populations were represented by (α-pinene/1,8-cineole/cis-sabinene hydrate/camphor/viridiflorol), (1,8-cineole/camphor/terpenyl acetate), (α-pinene/1,8-cineole/camphor), (1,8-cineole/camphor/4-terpineol) and (α-pinene/1,8-cineole/cis-sabinene hydrate/camphor/4-terpineol) chemotypes. Variation of phenological stage did not have a statistically significant effect on the yield and metal chelating activity of the essential oil. These results can be used to investigate the geographical location and the harvesting time of this plant for relevant industries.

Volatile and lipid analyses by gas chromatography/mass spectrometry and nutraceutical potential of edible wild Malva aegyptiaca L. (Malvaceae).

Volatile and lipid chemical compositions, and nutritional and antioxidant properties of Malva aegyptiaca, an edible wild plant largely distributed in North Africa, were investigated. Forty-nine compounds of volatiles were identified showing large qualitative and quantitative differences during three phenological stages. The flowering stage was characterized by the presence of a high number of terpenic compounds, among them dillapiole was found to be the major one (55.15%). The nutrient composition of leaves and fruits was investigated in the present work. Fruits' lipidic fraction was characterized by its high level of linoleic acid (n-6) (36.17%). Interestingly, leaves' lipidic fraction was characterized by its very high content of camphor (43.69%) and by its relatively high content of linoleinic acid (n-3) (14.69%). Furthermore, our results showed that the phenolic contents varied from 352 to 404 mg gallic acid equivalent/g ethanolic and acetonic extracts, respectively. These extracts revealed interesting antioxidant activities including free radical scavenging activity (EC(50) = 0.38-0.57 mg/ml) and reducing power (EC(50) = 0.12-0.18 mg/ml).

Variation in volatiles of Astragalus gombiformis Pomel.

The essential oils obtained by hydrodistillation (Clevenger apparatus) from aerial parts of Astragalus gombiformis were analysed by gas chromatography coupled with mass spectrometry (GC/MS). This study showed that the A. gombiformis essential oils are complex mixtures of important natural compounds, which varied qualitatively and quantitatively between cultivated and wild plants and between phenological stages of development. All analysed oils are characterized by the constant presence of phytol, 6,10,14-trimethyl-2-pentadecanone, 4-terpineol, and gamma-terpinene. This study is the first report on the chemical composition of essential oils from A. gombiformis and indicates that these oils should be more studied.