Steroids of the spirostan and furostan series from plants of the genus Allium. XXI. Structure of alliospiroside a and alliofuroside a from Allium cepa

Identification and Biological Activity of Antifungal Saponins from Shallot (Allium cepa L. Aggregatum Group)

“…The compounds corresponding to spots 3 and 4 were further purified by TLC, and the resultant compounds were subjected to NMR analysis to elucidate their chemical structure. The 1 H NMR and 13 C NMR data of spots 3 and 4 were identical to those of alliospiroside B (C 39 H 62 O 13 ) [[(25 S )-3β-hydroxyspirost-5-en-1β-yl] 2- O -(6-deoxy-α- l -mannopyranosyl)-β- d -galactopyranoside] and alliospiroside A (C 38 H 60 O 12 ) [[(25 S )-3β-hydroxyspirost-5-en-1β-yl] 2- O -(6-deoxy-α- l -mannopyranosyl)-α- l -arabinopyranoside], respectively (Figure ).…”

“…ALA and ALB are also contained in the collective fruit (ripened seeds) in the onion. 19,20 Thus, ALA and ALB likely are important in the defense system of collective fruit, preventing fungal attack of flowers and seeds, as well as the underground part of plants belonging to A. cepa L.…”

“…These compounds may function along with each other as a chemical barrier against such soilborne pathogens invading the shallot through the root and basal plate. ALA and ALB are also contained in the collective fruit (ripened seeds) in the onion. , Thus, ALA and ALB likely are important in the defense system of collective fruit, preventing fungal attack of flowers and seeds, as well as the underground part of plants belonging to A. cepa L.…”