New guaianolides and xanthine oxidase inhibitory flavonols from ajania fruticulosa
الكلمات الدالة
نبذة مختصرة
Two new guaianolides (1 and 2) were isolated from the aerial parts of Ajania fruticulosa along with a triterpene (alpha-amyrin), two plant sterols (beta-sitosterol and daucosterol), four flavonols [santin (3), axillarin (4), centaureidin, and 5,7,4'-trihydroxy-3, 3'-dimethoxyflavone], and five sesquiterpenes [ketoplenolide B, 9beta-hydroxyeudesma-4,11(13)-dien-12-oic acid, 9beta-acetoxyeudesma-4,11(13)-dien-12-oic acid, 1alpha,4alpha, 10alpha-trihydroxy-9alpha-angeloyloxyguaia-2,11(13)-dien-12, 6alpha-olide, and 3beta,4alpha-dihydroxyguaia-11(13),10(14)-dien-12, 6alpha-olide]. The structures of the new guaianolides were established as 1alpha-hydroperoxy-4beta,8alpha,10alpha, 13-tetrahydroxyguaia-2-en-12,6alpha-olide (1) and 1alpha-hydroperoxy-4alpha, 10alpha-dihydroxy-9alpha-angeloyloxyguaia-2,11(13)-dien-12, 6alpha-olide (2), respectively. Xanthine oxidase assays of all isolates revealed that santin (3) and axillarin (4) inhibited the enzyme with IC(50) values of 36.5 and 36.0 &mgr;M (that of allopurinol used as a positive control in the study was 24.2 &mgr;M), respectively.