Anti-anaphylactic properties of Thonningia sanguinea

The antianaphylactic effects of Crinum glaucum aqueous extract

The aqueous extract of Crinum glaucum was evaluated for its effects on antigen and histamine induced contraction of the ileum and on mediator release from the lungs of sensitized guinea pigs. The results show that the extract dose dependently inhibited the contractions induced by antigen and histamine in vitro and in vivo. The extract also inhibited, in a dose-dependent manner, the quantity of mediators antigenically released from the lungs and reduced the mepyramine resistant activity from the lungs. The results obtained indicate that the extract possesses antianaphylactic properties, which may account for its use as an antiasthmatic in traditional medicine.

Antioxidant properties of Thonningianin A, isolated from the African medicinal herb, Thonningia sanguinea

The antioxidant properties of Thonningianin A (Th A), an ellagitannin, isolated from the methanolic extract of the African medicinal herb, Thonningia sanguinea were studied using the NADPH and Fe2+/ascorbate-induced lipid peroxidation (LPO), electron spin resonance spectrometer and the deoxyribose assay. Th A at 10 microM inhibited both the NADPH and Fe2+/ascorbate-induced LPO in rat liver microsomes by 60% without inhibitory effects on cytochrome P450 activity. Th A was similar to the synthetic antioxidant, tannic acid, as an inhibitor of both the NADPH and Fe2+/ascorbate-induced LPO but potent than gallic acid, vitamin C and vitamin E. While Th A poorly scavenged the hydroxyl radical generated by the Fenton reaction it dose-dependently scavenged 1,1-diphenyl-2-picrylhydrazyl, superoxide anion and peroxyl radicals with IC50 of 7.5, 10 and 30 microM, respectively. Furthermore, Th A showed inhibitory effects on the activity of xanthine oxidase with an IC50 of 30 microM. In the deoxyribose assay both T. sanguinea and its methanolic component Th A showed only site-specific (Fe3+ + H2O2) but not non-site-specific (Fe3+ + EDTA + H2O2) hydroxyl radical scavenging suggesting chelating ability for iron ions. Spectroscopic studies showed that Th A enhanced absorbance in the visible region in the presence of Fe2+ ions. These results indicate that the antioxidant properties of Th A involve radical scavenging, anti-superoxide formation and metal chelation.

In vitro screening for the anti-anaphylactic agent in Thonningia sanguinea

Thonningia sanguinea, used prophylactically against bronchial asthma, is anti-anaphylactic and anti-asthmatic in guinea pigs when given orally. The aqueous extract of the plant and its fractions were screened in vitro for their effects on anaphylactic- and histamine-induced contractions, and the results compared with those obtained in vivo when the whole extract was administered orally. The comparison showed similar anti-anaphylactic properties of the plant material in the two systems of administration, but the effects on histamine-induced contractions differed from the in vivo ones, suggesting that the anaphylactic assay system should be preferred for the screening in vitro. The anti-anaphylactic substance(s) extracted into n-butanol. The active portions of the extracted components appeared to be stable to acid digestion. Thin layer chromatographic analysis of the butanol extract and preliminary chemical analysis suggest that these substances are polyhydroxy/phenolic in nature.