Bioactive saponins from Microsechium helleri and Sicyos bulbosus

Abstract

Eleven oleanane-type saponins (1-11) have been isolated from Microsechium helleri and Sicyos bulbosus roots and were evaluated for their antifeedant, nematicidal and phytotoxic activities. Saponins {3-O-β-D-glucopyranosyl (1→3)-β-D-glucopyranosyl-2β,3β,16α,23-tetrahydroxyolean-12-en-28-oic acid 28-O-α-L-rhamnopyranosyl-(1→3)-β-D-xylopyranosyl-(1→4)-[β-D-xylopyranosyl-(1→3)]-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranoside} (1), and {3-O-β-D-glucopyranosyl-2β,3β,16α,23-tetrahydroxyolean-12-en-28-oic acid 28-O-α-L-rhamnopyranosyl-(1→3)-β-D-xylopyranosyl-(1→4)-[β-D-xylopyranosyl-(1→3)]-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranoside} (2) were also isolated from M. helleri roots together with the two known compounds 3 and 4. Seven known structurally related saponins (5-11) were isolated from S. bulbosus roots. The structures of these compounds were established as bayogenin and polygalacic glycosides using one- and two-dimensional NMR spectroscopy and mass spectrometry. Compounds 7, 10, bayogenin (12) and polygalacic acid (13) showed significant (p<0.05) postingestive effects on Spodoptera littoralis larvae, compounds 5-11 and 12 showed variable nematicidal effects on Meloydogyne javanica and all tested saponins had variable phytotoxic effects on several plant species (Lycopersicum esculentum, Lolium perenne and Lactuca sativa). These are promising results in the search for natural pesticides from the Cucurbitaceae family.

Chemical evidence for the effect of Urochloa ruziziensis on glyphosate‐resistant soybeans

“…These kinds of compounds have also been reported to have detrimental effects on plant growth when released into the soil . These compounds have recently been investigated for their phytotoxic activity . As a result, a long glycosidic chain linked at C‐3 of the aglycone moiety was suggested as a key factor for phytotoxicity.…”

“…49 -51 These compounds have recently been investigated for their phytotoxic activity. 52 As a result, a long glycosidic chain linked at C-3 of the aglycone moiety was suggested as a key factor for phytotoxicity. In contrast, the relationship between aglycone structure and phytotoxicity remains unclear.…”

New Bioactive Semisynthetic Derivatives of 31-Norlanostenol and Obtusifoliol from Euphorbia Officinarum

“…Therefore, these compounds acted as postingestive antifeedants with varying potencies (3 > 12 > 14) with 12 having additional toxic action. The structure-activity relationships (SAR, Table 2) of these compounds showed that the most active IGRs (insect growth regulators) had a C-3 carbonyl group and a C-8 epoxide (7,12,18).…”

Natural Product-Based Biopesticides for Insect Control

“…469 In the same way, saponins from Microsechium helleri and Sicyos bulbosus showed significant postingestive effects on Spodoptera littoralis larvae. 470 The search for limonoids started way back when scientists started looking for the factor responsible for bitterness in citrus which has a negative impact on citrus fruit and the juice industry worldwide. The term limonoids was derived from limonin, the first tetranortriterpenoid obtained from citrus bitter principles.…”