Biological activities of Peganum harmala leaves

Ethyl acetate, chloroform, butanol and methanol extracts of the leaves of Peganum harmala were tested for antibacterial, antioxidant and antiviral activities. The antibacterial activity was evaluated by the determination of minimum inhibitory concentration (MIC) using the solid medium technique. The antiviral activity was evaluated against human cytomegalovirus (HCMV) strain AD-169 (ATCC Ref. VR 538) and Coxsackie B virus type 3 (CoxB-3) using diagnostic method ‘shell-vial’ culture. The antioxidant activity was evaluated using ammonium thiocyanate method. Among tested extracts, methanol and chloroform extracts displayed a higher antibacterial activity against gram-positive than gram-negative bacteria. The methanol extract demonstrated the highest antioxidant activity and good antiviral activity against HCMV.Key words: Peganum harmala, antimicrobial, antiviral, antioxidant, activities, leave

Natural Products among Brown Algae: The Case of Cystoseira schiffneri HAMEL (Sargassaceae, Phaeophyceae)

A chemotaxonomic study on the marine brown alga Cystoseira schiffneri collected from the Tunisian marine coast allowed us to identify kjellmanianone (1) and a new isololiolide derivative named schiffnerilolide (2). The structu re elucidati on and the assignment of relative con figurations of the isolated natur al products were based on advanced mass spectrometric and nuclear magnetic resonance techniques. This outcome suggested a close phylogenetic relationship of C. schiffneri with brown algae bel onging to genus Sargassum C. A GARDH. Molecular characterization using the nuclear small subunit rRNA (SSU rRNA) gene (18S) sequence as genetic marker was made. Pigme nt analysis showed a significant seasonal change of carotenoids, in particular of fucoxanthin and fucoxanthinol. Also galactolipids, the main constituents of the thylakoid membranes, showed remarkable seasonal changes

Essential Oil Constituents and Antioxidant Activity of Asplenium Ferns

Two fern species Asplenium adiantum-nigrum L. and Asplenium trichomanes L. collected from the Kroumiria region (Northwest of Tunisia) were individually submitted to hydrodistillation in a Clevenger type apparatus. Volatile organic compounds were identified by GC-MS and GC-FID. Thus, 35 compounds were identified in A. adiantum-nigrum essential oil accounting for 77.5% of the whole constituents dominated by palmitic acid (34.5%); however, only 29 volatiles were identified in A. trichomanes showing a high amount of phytol, an odorous diterpene alcohol, representing 14.4% of the total oil contents. The total phenolic content and the antioxidant effects of crude extracts from both pteridophytes were determined using Folin-Ciocalteu and 2,2′-diphenyl-1-picrylhydrazyl free radical-scavenging assays, respectively. A. adiantum-nigrum ethyl acetate extract is shown to be lower in total phenolic contents (49.3 mg gallic acid equivalent/g) than similar extract from A. trichomanes (55.4 mg GAE/g)

Effect of seasonal variation on the chemical composition and antioxidant and antifungal activities of Convolvulus althaeoides L. leaf extracts

The composition of polyphenols, chlorophylls and carotenoids of eight extracts of Convolvulus althaeoides L. leaves, harvested in two different seasons, winter and spring, and extracted by hot extraction method using four solvents (dichloromethane, chloroform, ethyl acetate and ethanol) with increasing polarity, were evaluated along with their antioxidant and antifungal activities. Qualitative and quantitative variations were observed in the composition based on two different high performance liquid chromatography systems, liquid chromatography-photodiode array detection coupled to either atmospheric pressure chemical ionization mass spectrometry or to electrospray ionization mass spectrometry, permitting the identification of 22 polyphenols, 11 chlorophyll derivatives and 10 carotenoid compounds. Polyphenolic compounds were predominant in extracts from leaves collected in winter, whereas pigments were predominant in the spring collections. Antioxidant activities of the extracts were determined by DPPH radical scavenging method, revealing a half inhibition concentration (IC50) ranging from 0.1369 ± 0.0272 mg g−1 to 0.432 ± 0.0018 mg g−1, with no correlation to seasonal fluctuation. Concerning antifungal assays, ethyl acetate and ethanol extracts have been shown to be the most active against dermatophytes (T. rubrum, T. menthagrophytes, M. canis), with inhibiting percentages reaching 100% with 50 mg mL−1. Moreover, ethyl acetate and ethanol extracts showed a maximum inhibition potential with minimum inhibitory/fungicidal concentrations ranging from 0.78 to 6.25 mg mL−1 on Candida spp. cultures. The winter collect of these extracts showed an inhibitory effect of 90% on Candida albicans germ tubes formation, at a concentration of 3.1 mg mL−1. In conclusion, seasonality seems to influence the quality and the quantity of natural substances from leaves of C. althaeoides L., which have major importance on the antioxidant and the antifungal effectiveness

Metabolite profiling of polyphenols in the Tunisian plant Tamarix aphylla (L.) Karst

In this study, a detailed investigation on the composition of polyphenols of Tamarix aphylla (L.) Karst., consisting of phenolic acids and flavonoids, was carried out. In order to optimize the yield of secondary metabolites, three extraction techniques were compared, including dynamic maceration, ultrasound-assisted extraction and Soxhlet extraction. The latter technique provided the best results in terms of both recovery and selectivity, using ethyl acetate as extraction solvent for 2h. The analysis of T. aphylla polyphenols was performed by means of HPLC-UV/DAD, HPLC-ESI-MS and MS(2), using an ion trap mass analyzer. Phenolic acids and flavonoids were separated on an Ascentis C18 column (250mm×4.6mm I.D., 5μm), with a mobile phase composed of 0.1M formic acid in water and acetonitrile, under gradient elution. The proposed method was fully validated in agreement with ICH guidelines and then applied to the analysis of T. aphylla leaves and stems. A total of 14 phenolic compounds were characterized for the first time in this plant extracts by using UV, MS and MS(2) data. The amount of total phenolics was found to be 993.1±22.5μg/g in the leaves and 113.1±25.8μg/g in the stems, respectively. The most abundant constituents found in the leaves include ellagic acid (211.4±10.8μg/g), quercetin (125.7±4.7μg/g) and gallic acid (120.6±1.2μg/g), whereas those in the stems were ellagic acid (44.4±3.9μg/g), gallic acid (24.3±3.3μg/g) and kaempferol (16.3±1.6μg/g). The developed method can be considered a useful tool for the metabolite profiling of T. aphylla, which represents a potential source of bioactive compounds to be used in phytotherapy

Antibacterial, Antifungal and Cytotoxic Activities of Two Flavonoids from Retama raetam Flowers

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