Studies on Polyterpenoids and their Glycosides. III

Two Major Saponins from Seeds of Barringtonia asiatica: Putative Antifeedants toward Epilachna sp. Larvae

“…A portion of the 1-butanol extractives were also degraded to the free aglycons emulating Nozoe's conditions, whereby A 1 -barrigenol ( 1 ) and cammelliagenin A ( 2 ) were isolated, thus confirming Nozoe's observations. Unlike earlier reports, no d -fucose was observed in the GC profile of the 1-butanol extractives after methanolysis and per-trimethylsilylation, an outcome that may suggest a further variation of saponin content of B. asiatica seeds with geographical location.…”

“…Preliminary work on the minor saponins of B. asiatica indicates that several are derived from camelliagenin A ( 2 ), which also supports Nozoe's observations . They also appear to have less antifeedant activity toward Epilachna than those derived from A 1 -barrigenol ( 1 ).…”

“…There has been surprisingly little published work on the isolation of natural products from B. asiatica. Nozoe, in 1934, extracted a mixture of saponins (A 1 -barrinin) from B. asiatica. On acidic hydrolysis, A 1 -barrinin produced a mixture of sapogenins (A 1 -barrigenin), together with a mixture of several sugars that were later shown to be fucose, galactose, glucose, and glucuronic acid in a ratio of 1:2:2:2.…”