Phytochemical constituents and hepatoprotective activity of Viburnum tinus

From the leaves of Viburnum tinus L. (Adoxaceae) two acylated iridoid glucosides (viburtinoside A and B), a coumarin diglucoside scopoletin 7-O-beta-D-sophoroside and a natural occurred dinicotinic acid ester 2,6-di-C-methyl-nicotinic acid 3,5-diethyl ester were isolated. In addition to these, 10 known compounds were isolated, namely two bidesmosidic saponins, a hexamethoxy-flavone and five flavonol glycosides, as well as suspensolide A and oleanolic acid were isolated for the first time in this genus and species, respectively. The structures were determined mainly by spectroscopic methods (UV, IR, ESI-MS, 1H-, 13C NMR and DEPT). Toxicity of the investigated extract was determined (LD50=500 mg/kg). CCl4-induced hepatotoxicity has been evaluated in terms of the determination of alanine aminotransferase (ALT), aspartate aminotransferase (AST), lipid peroxide and nitric oxide levels in serum and compared using adult male rats weighing 150-180 g. Their highly elevated levels were significantly reduced by treatment with the investigated aqueous methanol extract in dose-dependent manner.