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BİTİŞ, LEYLA

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    PublicationOpen Access
    In vitro antiproliferative, antioxidant, anti-inflammatory activities and phenolic profile of Centaurea saligna ( K.Koch) Wagenitz
    (MARMARA UNIV, 2022) ŞEN, ALİ; Yildirim, Aybeniz; Sen, Ali; Goger, Fatih; Ozakpinar, Ozlem Bingol; Bitis, Leyla
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    PublicationOpen Access
    Two Acylated Isoscutellarein Glucosides with Anti-Inflammatory and Antioxidant Activities Isolated from Endemic Stachys Subnuda Montbret & Aucher ex Benth
    (SLOVENSKO KEMIJSKO DRUSTVO, 2019-12-18) DOĞAN, AHMET; Sen, Ali; Goger, Fatih; Dogan, Ahmet; Bitis, Leyla
    In this study, we report anti-inflammatory and antioxidant activities of two acylated isoscutellarein glucosides isolated from ethyl acetate extract of Stachys subnuda aerial part. 4'-O-methylisoscutellarein-7-O-2 ''-O-(6 ''' acetyl-beta-D-allopyranosyl)-beta-D-glucopyranoside (SS1) and isoscutellarein-7-O-2 ''-O-(6 '''-O-acetyl-beta-D allopyranosyl)-beta-D -glucopyranoside (SS2) were isolated as major compounds from ethyl acetate extract (SSEA). Also, 2 hydroxycinnamic acid derivatives, and 5 isoscutellarein glucoside derivatives in the SSEA were identified using LC-MS/MS. SS1 with IC50 values of 2.35 and 1.98 mu g/mL and SS2 with IC50 values 13.94 and 12.76 mu g/mL showed fairly strong antioxidant activity against DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid) radicals, respectively. SS1 and SS2 inhibited 5-lipoxygenase (5-LOX) activity with IC(50 )values of 47.23 and 41.60 mu g/mL, respectively. The results demonstrated that SS1 and SS2 have significant anti-inflammatory and antioxidant potential. Acylated flavonoid glycosides have been first reported for Stachys subnuda. Also, the activities of SS1 and SS2 have been investigated for the first time in this study.
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    PublicationOpen Access
    Flavonoids and biological activities of various extracts from Rosa sempervirens leaves
    (TAYLOR & FRANCIS LTD, 2017-03-04) ŞEN, ALİ; Bitis, Leyla; Sen, Ali; Ozsoy, Nurten; Birteksoz-Tan, Seher; Kultur, Sukran; Melikoglu, Gulay
    Rosa sempervirens L. (Rosaceae) growing wildly in Turkey is used in folk medicine for various indications. Here, we report the isolation of four flavonoids and determination of the total phenolic and flavonoid contents and the antimicrobial and antioxidant activities of various extracts from R. sempervirens leaves. Antioxidant activity was determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS). The total phenolic and flavonoid contents were determined using the Folin-Ciocalteu and AlCl3 methods, respectively. The antimicrobial activity was evaluated by the broth microdilution method against seven microbial species. The ethyl acetate extract (E) had significant antioxidant activity with half maximal inhibitory concentration (IC50) values of 3.96 in the DPPH and 2.92 mg/mL in the ABTS assay. The total phenolic (203.8 mg gallic acid equivalents/g extract) and total flavonoid (95.81 mg catechin equivalents/g extract) contents of the E extract were significantly higher as compared to other extracts. The E extract exhibited strong antimicrobial activity against Candida albicans with a minimum inhibitory concentration of 39 mg/mL. Quercetin 3-xyloside, quercitrin and hyperoside were isolated from the E extract and quercetin, from the chloroform extract, and quercetin and hyperoside were identified for the first time in this species. Quercitrin was found to be a major compound in the E extract. Antimicrobial activity of R. sempervirens was also reported for the first time. These results indicate that the E extract has significant antioxidant and antimicrobial activity, probably due to flavonoids as well as other phenolic compounds in the E extract, acting individually or in combination.