HPTLC quantification, assessment of antioxidant potential and in vivo hypoglycemic activity of Scorzonera latifolia (Fisch. & Mey.) DC and its major compounds

Scorzonera L. (Asteraceae) species have long been the topic of many phytochemical, analytical, and biological studies since various species of the Scorzonera genus have been widely used as food and medicinal purposes. Apart from its traditional use to relieve pain, promote wound healing, treat helminth infections or women infertility, Scorzonera latifolia (Fisch. & Mey.) DC is also used for its antidiabetic activity. We aimed to investigate antidiabetic activity of the aerial parts of the title plant and its major secondary metabolites (hyperoside, isoquercitrin, 7-O-methylisoorientin, isoorientin, swertisin, chlorogenic acid, 4,5-O-dicaffeoylquinic acid and hydrangenol-8-O-β-glucoside) isolated from aerial parts in alloxan-induced diabetic mice. Blood glucose levels were measured four times: before the treatment, after 1^st, 2^nd, and 4^th hours of sample treatments (100 mg/kg i.p.). S. latifolia extract displayed notable decline after 4 hours of administration. Among the metabolites; swertisin, 7-O-methyl-isoorientin, and hydrangenol-8-O-β-glucoside were associated with significant reduction on blood glucose level of alloxan-induced diabetic mice. Due to the strong relationship between oxidative stress and diabetes, antioxidant activity of S. latifolia was additionally tested. Furthermore, 4,5-O-dicaffeoylquinic acid, chlorogenic acid, hyperoside, and swertisin contents as major components of the extract were quantified by HPTLC-densitometry, as their biological effects can be attributed to their phenolic contents.