S. Hastifolia bitkisi üzerinde fitokimya ve biyolojik aktivite araştırmaları

PHYTOCHEMICAL AND BIOLOGICAL INVESTIGATIONS ON SCUTELLARIA HASTIFOLIA L. Scutellaria L. (Lamiaceae) species have long been the subject of many phytochemical, analytical and biological studies. In the context of this thesis, four Scutellaria taxa, S. hastifolia L., S. velenovskyi Rech., S. orientalis L. subsp. pinnatifida and S. albida L. subsp. albida from Turkey were screened for their antioxidant profiles by calculating their total antioxidant capacities as well as total phenol and total flavonoid contents. Based on the preliminary data, S. hastifolia was selected for the detailed phytochemical and biological investigations. From the acetone and MeOH extracts, 17 compounds were isolated, including a new one, by using several chromatographic techniques. Isolated compounds were categorized as ethylcyclohexane derivatives (isorengyol, isorengyoside, cleroindicin B, cleroindicin F), phenylethanoid glycosides (cornoside, calceolarioside D, hastifolioside, neocalceolarioside D, calceolarioside B, verbascoside), flavonoids (apigenin 7-O-β-D-glucopyranoside, scutellarein 7-O-β-D-glucopyranoside, hispidulin 7-O-β-D-glucopyranoside, hispidulin 7-O-β-D-glucuronopyranoside), sugar ester (6-O-caffeoylglucopyranose) and sugar molecules (glucose, saccharose). The pure compounds were then investigated for their effects on DPPH, LP and LOX inhibition similarly as crude extracts of S. hastifolia. All crude extracts of S. hastifolia, highly interacted with DPPH, while in LP inhibition assay the acetone extract showed remarkable activity. In LOX inhibition assay, only MeOH extract showed significant inhibition while other extracts did not. Furthermore, all of the isolates highly reacted with DPPH while only glycosides of apigenin and scutellarein along with calceolarioside D showed moderate LP inhibition. Moreover, all of the isolates showed weak soybean LOX inhibition at the tested concentration. Additionally, the qualitative and quantitative analysis of several phenylethanoid glycosides and flavonoids in all Scutellaria species were performed comparatively by using HPLC-DAD in order to characterize their main phenolic constituents. Keywords: Scutellaria hastifolia, antioxidant and antiinflammatory activities, secondary metabolites, hastifolioside, HPLC-DAD