Isolation of steroidal sapogenins implicated in experimentally induced cholangiopathy of sheep grazing Brachiaria decumbens in Brazil

As part of an experimental study, crystal-associated cholangiopathy was induced in 9 sheep by grazing pure pastures of Brachiaria decumbens in Brazil. One of these sheep showed characteristic lesions of photosensitization. The analysis of the B decumbens samples by acidic hydrolysis followed by TLC and infrared spectrum revealed diosgenin as the principal sapogenin present in the plant. In the rumen contents samples from the B decumbens-grazing group were identified by TLC, 1H and 13C NMR and EIMS as epismilagenin, episarsasapogenin, and a mixture of smilagenin and sarsasapogenin. In the bile samples from the B decumbens-grazing group, TLC analysis demonstrated 2 compounds similar to epismilagenin and episarsasapogenin. However, by this same method, those compounds were not observed in the rumen contents and bile from 2 sheep which served as control animals. The P chartarum spore counts remained very low during the experimental period.

Triterpenoid glycosides and a triterpene from Ilex brevicuspis

Two saponins and a sapogenin were isolated from the leaves of Ilex brevicuspis. Their structures were established by means of spectroscopic methods as brevicuspisaponin 1 (3-O-alpha-L-arabinopyranosyl-20(S)-19 alpha,24-dihydroxyursolic acid), brevicuspisaponin 2 (3-O-alpha-L-arabinopyranosyl-20(S)-19 alpha,23,24-trihydroxyursolic acid) and 23-methylester of 20(S)-3 beta,19 alpha,24-trihydroxyurs-12-en-23,28-dioic acid.

Matesaponin 5, a highly polar saponin from Ilex paraguariensis

The structure of matesaponin 5, a novel saponin isolated from the leaves of the Ilex paraguariensis, was established as ursolic acid-3-0-{beta-D-glucopyranosyl-(1->3)-[alpha-L-rhamnopyranosyl-(1->2)]-alpha-L- arabino pyranosyl}-(28->1)-beta-D-glucopyranosyl-(1->4)-beta-D-glucopyranosyl-(1 ->6)-beta-D-glucopyranosyl] ester.

Triterpenoid saponins from Ilex paraguariensis

The leaves of Ilex paraguariensis have yielded three new saponins named matesaponins 2, 3, and 4 [1-3], which have been characterized by chemical and nmr methods as ursolic acid 3-O-[beta-D-glucopyranosyl-(1-->3)-[alpha-L-rhamnopyranosyl- (1-->2)]]-alpha-L-arabinopyranosyl]-(28-->1)-beta-D-glucopyranosyl ester, ursolic acid 3-O-[beta-D-glucopyranosyl-(1-->3)-alpha-L-arabinopyranosyl]-(28-- >1)- [beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl]ester, and ursolic acid 3-O-[beta-D-glucopyranosyl-(1-->3)-[alpha-L- rhamnopyranosyl-(1-->2)]]-alpha-L-arabinopyranosyl]-(28-->1)-[beta -D- glucopyranosyl-(1-->6)-beta-D-glucopyranosyl]ester, respectively.