Determination of phytochemical contents by LC/QTOF/MS and evaluation of in-vitro biological activities of 2 Peltigera lichens from Bursa.

Lichens are symbiotic associations of algae and fungi. They are edible as food and have been used in traditional medicine for years. It is aimed to screen Peltigera praetextata (Flörke ex Sommerf.) Zopfand and Peltigera elisabethae Gyeln. phytochemically by LC/QTOF/MS and according to the constituents to evaluate the antioxidant, tyrosinase inhibitory, and antibacterial activities. In total 54 of metabolites detected by LC/QTOF/MS were common in both species. According to LC/QTOF/MS scanning results, alkaloids, iridoid glycosides, phenolics, cyanogenetic glycosides, and terpenic structures were detected. DPPH, ABTS, superoxide radical scavenging activities, and metal chelating capacity IC50 values were 84.55, 9.349; 51.27, 9.127; 95.01, 58.65 and 20.57, 70.08 µg/mL., respectively. The CUPRAC reducing power was determined as 4.69 and 9.57 TEACCUPRAC, respectively. Tyrosinase inhibitor activity were found to be 86.95 and 196.7 µg/mL. Both lichens did not show antimicrobial effects. As a result of the antioxidant and tyrosinase inhibitor activities it was seen that their activities were significant and further in vivo studies could be carried out on this lichens.

Isolation of Chemical Constituents of Centaurea virgata Lam. and Xanthine Oxidase Inhibitory Activity of the Plant Extract and Compounds.

BACKGROUND: Centaurea virgata Lam. is a species widely used in the traditional medicine in Turkey for the treatment of diabetes, allergy and gastric ulcers. The rationale of its use in the therapy has not been studied previously, therefore the present work aimed at the chemicalpharmacological evaluation of the plant. OBJECTIVE: The xanthine oxidase (XO) inhibitory activity of the MeOH extract and its subextracts (n-hexane, CHCl3 and remaining MeOH-H2O) prepared from C. virgata was investigated in vitro. Moderate activity was exerted in case of the CHCl3 extract (98.9 ± 15.8 µg/mL), therefore constituents of this extract were analysed. METHOD: Different purification steps, such as VLC, CPC, PLC and crystallization were used for the isolation, and ESIMS, NMR, LC-MS and authentic standards were applied for identification of the compounds. XO inhibitory and DPPH assays were used for evaluation of the bioactivities. RESULTS: Sesquiterpenes [8α-hydroxysonchucarpolide, 8α-(3,4-dihydroxy-2-methylenebutanoyloxy)- dehydromelitensine, and cnicin], flavones (apigenin, hispidulin, salvigenin, eupatorin, 3'-methyleupatorin), and the flavonol isokaempferide were isolated from the active extract. The XO-inhibitory activity of these compounds was analyzed using allopurinol as a positive control (IC50 7.49 ± 0.29 µM). It was found that sesquiterpenes and flavonoids, containing 7- OMe group, are inactive. CONCLUSION: 7-Hydroxyflavones (apigenin and hispidulin) exerted significant XO inhibitory effect with IC50 values of 0.99 ± 0.33 µM and 4.88 ± 1.21 µM, respectively. Therefore, these compounds are responsible for the XO-inhibitory effect of the extract. The free radical scavenging activity of the isolated flavonoids was determined by DPPH assay, and it was stated that none of the compounds have substantial antioxidant activity, therefore the reduced generation of reactive oxygen species may be the consequence only of XO inhibition.