A new bioactive metabolite from Xanthoria steineri .

The ether extract of the lichen Xanthoria steneri Lamb yielded two new octanoic acid derivatives identified as 3-hydroxy 2,4, 6-trimethyl octanoic acid (xantoric acid A) and 3-O-[3'-hydroxy-2',4',6'-trimethyl octanoate]-2,4,6 trimethyl octanoic acid (xanthoric acid B). In addition, 3-methyl orsellinic acid methyl ester (2, 4-dihydroxy-3,6-dimethyl benzoic acid methyl ester), physcion and 5 alpha-stigmast-7-en-3 beta-OI were further isolated and identified on the basis of spectral data. The biological profile of xanthoric acid B revealed a wide range of bioactivity including cytotoxicity, anticonvulsant, antibacterial and antimycotic properties.