Identification and structure determination of four triterpene saponins from some Middle‐East plants

Abstract

Four triterpene saponins were isolated from Arenaria filicaulis Boiss., Phytolacca dioica L. and Koelreuteria paniculata Laxm. Their structures and conformational behaviour were investigated by one-and twodimensional 1 H and 13 C NMR spectroscopy. Complete 1 H and 13 C assignments were achieved.

Lupane Triterpenes with a δ-Lactone at Ring E, from Lippia mexicana

“…The β-orientation of this group was established by NOESY interactions of H-21 with CH 3 -30, H-22α, H-22β (weak), and H-19 (weak) and by the absence of any interaction between H-21 and CH 3 -28. Comparison of the NMR data of ring E with those of other 21β-hydroxy lupanes , gave further support to this assumption. Thus, the structure of lippiolic acid ( 3 ) was established as 21β-hydroxy-3,4- seco -lupa-4(23),20(29)-dien-3-oic acid.…”

“…Thus, the differences between 1 and 2 were in ring A. The presence of a second isopropenyl group in 2 was deduced from the signals at 13,14 gave further support to this assumption. Thus, the structure of lippiolic acid (3) was established as 21β-hydroxy-3,4-seco-lupa-4(23),20(29)dien-3-oic acid.…”

Structural Elucidation of Saponins

“…For instance, the gradient selected single quantum multiple bond correlation [23] has the advantage of yielding numerical values of small long-range couplings useful for stereochemical and conformational analysis.…”

Triterpenoids

“…110 Coccinioside K is a betulinic acid saponin from Coccinia indica 111 and a lupane saponin has been isolated from Arenaria filicaulis. 112…”