Studies on Nepalese Crude Drugs. XXXI. On the Diterpenoid Constituents of the Aerial Part of Scutellaria discolor COLEBR.

Abstract

From the aerial part of Scutellaria discolor, eight new neoclerodane diterpenes (compounds 3, 4, 6, 8, 9, 10, 11 and 12) were isolated together with clerodin, dihydroclerodin-I, clerodin hemiacetal (14-hydro-15β-hydroxyclerodin), jodrellin A, scutaltisin, squalene, 24-methylenecycloartanol and a mixture of 3-epioleanolic acid and 3-epiursolic acid. The structures of new compounds were determined by spectroscopic and chemical methods as follows : 3, 15β-ethoxy-14-hydroclerodin; 4, 15α-ethoxy-14-hydroclerodin; 6, (6α)-19-O-acetyl-4, 18 : 11, 16 : 15, 16-triepoxyneoclerodane-6, 15, 19-triol (6-O-deacetyl-14-hydro-15-hydroxyclerodin); 8, 6α-O-acetyl-2, 19 : 4, 18 : 11, 16 : 15, 16-tetraepoxy-14-neoclerodene-6, 19-diol (19-O-deacetyljodrellin A); 9, 10, 11, and 12, 6α-O-acetyl-15β, 19β-di-O-ethyl-, 6α-O-acetyl-15α, 19β-di-O-ethyl-, 6α-O-acetyl-19β-O-ethyl- and 6α, 19-di-O-acetyl-2, 19 : 4, 18 : 11, 16 : 15, 16-tetraepoxyneoclerodane-6, 15, 19-triol, respectively.