Antimicrobial and Antioxidant Efficacy of the Lipophilic Extract of Cirsium vulgare.

The aim of this study was to investigate the compounds in the hexane extract of Cirsium vulgare (Savi.) Ten. and to determine the antibacterial, antifungal, and antioxidant activities of different extracts. The Cirsium vulgare (NGBB 7229) plant was collected from Turkey's Trakya region. Crude extracts were obtained using different solvents. The chemical composition of Cirsium vulgare was determined in hexane extract using gas chromatography mass spectrometry. The antioxidant activities of the extracts were evaluated by Trolox equivalent antioxidant activity (TEAC), ferric-reducing antioxidant power (FRAP), cupric-reducing antioxidant capacity (CUPRAC), the ß-carotene bleaching method, and the determination of superoxide anion scavenging activities. The antibacterial activity was tested against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, and Salmonella typhimurium, whereas the antifungal activity was tested against Candida albicans, Candida glabrata, Candida parapsilosis, Candida krusei, Penicillium chrysogenum, and Aspergillus fumigatus by applying microdilution methods. A total of 41 bioactive compounds were identified using the GC-MS library. Terpenoids were found to be dominant (52.89%), and lup-20(29)-en-3-yl-acetate and lupeol were the most abundant terpenoids. The highest total flavonoid content (25.73 mg catechin/g) and antioxidant capacity were found in the methanolic extract. The highest antibacterial activity was detected against Bacillus subtilis in the ethyl acetate extract, and the highest antifungal activity was found against Candida krusei and Aspergillus fumigatus in the hexane extract. The observed antioxidant characteristics of the C. vulgare extracts could be attributed to the presence of flavonoids. The high antifungal activity of the hexane extract against all fungal strains can be attributed to its constituents, i.e., terpenoids. This study discloses the potential antioxidant and antimicrobial activities, including some bioactive components, of Cirsium vulgare and implies that Cirsium vulgare holds possible applications in the food and pharmaceutical industries as an antioxidant, antibacterial, and antifungal agent.

Antioxidant and tyrosinase inhibitory activities of flavonoids from Trifolium nigrescens Subsp. petrisavi.

Trifolium nigrescens was researched for its chemical constituents for the first time. Bioassay-guided isolation of the EtOAc extract from the leaves of T. nigrescens resulted in the purification of a new biflavone, 4''',5,5″,7,7″-pentahydroxy-3',3'''-dimethoxy-3-O-ß-d-glucosyl-3″,4'-O-biflavone (1) along with eleven known compounds consisting of three phenolics (2-4), and eight flavonoid glycosides (5-12). Their structures were determined by extensive 1D and 2D NMR, and MS data analyses. The isolated compounds were evaluated for their antioxidant activity and inhibitory activity on mushroom tyrosinase. Highly potent inhibitions were found by compounds 7 (IC50 = 0.38 mM), 8 (IC50 = 0.19 mM), and 12 (IC50 = 0.26 mM) when compared with standard tyrosinase inhibitors kojic acid (IC50 = 0.67 mM) and l-mimosine (IC50 = 0.64 mM). The antioxidative effect of the isolated compounds and the extracts were determined by using ß-carotene-linoleic acid, DPPH(•) scavenging, ABTS(+•) scavenging, superoxide scavenging, and CUPRAC assays. The experimental findings indicated that all the compounds demonstrated activity in all antioxidant activity tests employed except for the compounds 2-6. Compounds 2-6 showed moderate activity only in ABTS(+•) scavenging assay. The new compound 1 exhibited better activity than standard α-tocopherol in DPPH(•) scavenging, and ABTS(+•) scavenging assays. The results show that T. nigrescens can be regarded as a potential source of antioxidant compounds and tyrosinase inhibitors of significance in both the pharmaceutical and food industries.