Phytochemistry of Homalium zeylanicum (Flacourtiaceae) and Serjania salzmanniana (Sapindaceae)
[Thesis]
O. A. Ekabo
N. R. Farnsworth
University of Illinois at Chicago, Health Sciences Center
1994
174
Ph.D.
University of Illinois at Chicago, Health Sciences Center
1994
A phytochemical study of Homalium zeylanicum led to the isolation of eight novel and several known compounds. Salirepin, salireposide and the three related analogs, homaloside B, C and D are being reported as occurring in a species of the Flacourtiaceae for the first time. This group of phenolic glucosides is restricted to the Salicaceae (Order: Salicales) and may be considered a taxonomic marker for the family. Their presence in the Flacourtiaceae (Order: Violales) may have chemotaxonomic significance. The novel compounds from H. zeylanicum comprise an iridoid glucoside (6-O-(34usd \sp{\prime\prime}usd-dimethoxycinnamoyl)catalpol), a lignan (zeylanicin, (7-methoxy-8-hydroxydehydro-diconiferyl alcohol)), an acyclic ester(1-hydroxy-6-oxocyclohex-2-enoic acid methyl ester), a degraded carotenoid (3-hydroxy-usd\betausd-ionyl-usd\betausd- scD-glucopyranoside) and four benzenoid glycosides, homaloside A (1-O-benzyl-3-O-benzoyl-(usd\alphausd- scL-arabinopyranosy1-(1usd \tousd4)-usd\betausd- scD-glucopyranoside), homaloside B (1-(2-methoxybenzoyloxy) methyl-5-hydroxyphenyl-usd\betausd- scD-glucopyranoside), homaloside C (1-furoyloxymethyl-5-hydroxy phenyl-usd\betausd- scD-glucopyranoside) and homaloside D (1-(1-hydroxy-6-oxo-cyclohex-usd2usd -ene-carboxymethyl)-5-hydroxyphenyl-6-O-benzoyl-usd\betausd- scD-glucopyranoside). Four monodesmosidic saponins were obtained from Serjania salzmanniana and evaluated for molluscicidal action against Biomphalaria alexandrina, a vector of Schistosoma mansoni in the Nile Valley, Egypt. Two novel saponins named salzmannianoside A (3usd\betausd-hydroxy-23-formylolean-12-ene-28-oic acid 3-O- (usd\betausd- scD-glucopyranosyl-(1usd\tousd4)) - (usd\alphausd- scL-rhamnopyranosyl-(1usd\tousd2)) -usd\alphausd- scL-arabinopyranoside),salzmannianosideB(3usd \betausd,23-dihydroxyolean-usd1usd 2-ene-28-oic acid 3-O- (usd\betausd- scD-glucopyranosyl-(1usd\tousd4)) - (usd\alphausd- scL-arabinopyranosyl(1usd \tousd3)-usd\alphausd- scL-rhamnopyranosyl-(1usd \tousd2)) -usd\alphausd- scL-arabinopyranoside) usd\{usd69usd\}usd and the known saponins pulsatilla saponin D (3usd\betausd,23-dihydroxyolean-12-ene-28-oic acid-3-O- (usd\betausd- scD-glucopyranosyl-(1usd\tousd4)) - (usd\alphausd- scL-rhamnopyranosyl-(1usd\to usd2)) -usd\alphausd- scL-arabinopyranoside usd\{{\bf 67}\}usd and 3usd\betausd-hydroxyolean-12-ene-28-oic acid 3-O- (usd\betausd- scD-glucopyranosyl-(1usd\to usd4)) usd\alphausd- scL-rhamnopyranosyl-(1usd \tousd2)) -usd\alphausd- scL-arabinopyranoside were isolated from this plant. All the saponins were molluscicidal, causing greater than 90% kill at a concentration of 10 ppm except for salzmannianoside B which caused only a 70% mortality at 20 ppm. All the structures were solved by 1D and 2D nmr spectroscopy in combination with the other spectral (ms, ir, uv) and chemical techniques.