Isolation, identification of secondary metabolites from <i>Salvia absconditiflora</i> and evaluation of their antioxidative properties

Salvia absconditiflora Greuter & Burdet (Synonym Salvia cryptantha Montbret & Aucher ex Benth) has been used extensively for traditional medicine. The aerial of plant material was boiled in water then filtrated. The filtrate was partitioned with ethyl acetate and n-butanol sequentially to yield the ethyl acetate and n-butanol extract. A sample of water was lyophilized to yield the water extract. Ethyl acetate extract revealed the highest antioxidant activity and included the most phenolic compounds among the extracts. Hence, ethyl acetate extract was subjected to chromatographic techniques. Ursolic acid (1), crismaritin (2), luteolin (3), rosmarinic acid methyl ester (4), 3,4-dihydroxyl benzaldehyde (protocatechuic aldehyde) (5), caffeic acid (6), apigenin-7-O-β-glucoside (7), rosmarinic acid (8) and luteolin-7-O-β-glucoside (9) were isolated and the structures were elucidated by spectroscopic methods including 1D, 2D NMR, and LC-TOF/MS. Cirsimaritin (2), luteolin (3), rosmarinic acid methyl ester (4), rosmarinic acid (8), luteolin-7-O-β-glucoside (9) displayed the considerable antioxidant activity.