Investigation of antiproliferative, antidiabetic and antioxidant potentials of secondary metabolites isolated from the plant Verbascum leiocarpum

In this study, the antiproliferative, antioxidant and antidiabetic activities of 4 different Verbascum species (V. alyssifolium, V. leiocarpum, V. ozturkii ve V. tuna-ekimii) endemic to Erzincan were investigated. V. leiocarpum species, which has the highest antiproliferative and antidiabetic activity among these four plants, was subjected to chromatographic (column, thin layer, flash and prep HPLC) processes in order to isolate compounds responsible for the activities. As a result of the chromatographic studies on the above-ground part of the plant; catalpol (S-1), ajugol (S-2), eriodictyol (S-3), luteolin (S-4) and 10-O-cinnamoyl-catalpol (S-5), on the root part, apigenin (S-6), 6-deoxy melittoside (S-7), poliumoside (S-8), verbascoside (S-9), isoverbascoside (S-10), ferruginoside C (S-11), ferruginoside D (S-12), harpagoside (S-13), trans-cinnamic acid (S-14) and ursolic acid (S-15) were isolated. The structures of the isolated molecules were elucidated by spectroscopic techniques (NMR). Ferruginoside D (S-12) was reported for the first time in a natural source. Antiproliferative activity against Beas2B (normal lung cell), RPE (normal retinal cell), HSF (normal skin cell), A172 (brain cancer cell), C6 (brain cancer cell), HeLa (cervical cancer), A2780 (ovarian cancer), SW620 and HT29 (colon cancer) cell lines, antioxidant activity (DPPH, ABTS, FRAP) and antidiabetic (α-glucosidase enzyme inhibition) activity of isolated compounds were evaluated.