Chemical and biological study of Withania somnifera (L.) dunal leaves growing in Upper Egypt: Beni-Suef region

As a part of our research programme of investigating some medicinal plants cultivated in Beni-Suef Governorate (Egypt) as anticancer agents. Bioassay-guided fractionation study using brine shrimp lethality and Ehrlich Ascites carcinoma assays revealed that the PE extract (PE) of Withania somnifera (L.) Dunal leaves retained most cytotoxic activity among other extracts. The total phenolics, flavonoids and tannins content of the total alcoholic extract were determined. The contents of PE of the fatty acids (FA) and the unsaponifiable matter (USM) were determined using GC/MS. The results showed that total phenolic, flavonoids and tannins content were 365mg, 2.6mg and 38.9mg/1g dry weight respectively. GC/MS analysis revealed presence of 38 and 25 compounds in FA and USM, respectively. In this study, we report the isolation and identification of a new fatty alcohol: "3, 7, 11, 16 tetramethyl-heptadecane-2-en-1ol" using HR-ESI-MS, 1D and 2D NMR spectroscopic data, along with four known sterols: lupeol, stigmasterol, β-sitosterol and cholesterol from USM by chromatographic techniques. The cytotoxicity of the new fatty alcohol was further studied using K562 cell line and Lactate Dehydrogenase Assay (LDH). Results showed 52% inhibition of K562 cells at a concentration of 0.033μM and IC50 at 64.2μM. It could be concluded that Withania somnifera leaves could serve as an anticancer agent and an adjuvant therapy in resistance to chemotherapy.