Inhibitory Effects Of Methanol Extracts Research Articles

Evidence for Naturally Occurring Inhibitors of Archegonial Differentiation in Lygodium japonicum

AbstractArchegonial differentiation in prothallia of Lygodium japonicum was inhibited when the filtrate of conditioned medium or the extracts of prothallia with organic solvents were added to the medium. By varying the timing of treatment with the methanol extract, archegonial differentiation was shown to start at least 4 days before microscopically detectable change. The inhibitory effect of methanol extract was nullified by transferring the treated plants to a fresh medium omitting the methanol extract, so that the archegonial formation became discernible 6 days after the transfer.The inhibitory activity was stable in both acidic and basic solutions at room temperature, and was partially lost by boiling at pH 3 or 11 for 30 min. The inhibitor, which could be retrieved from the filtrate and the methanol extract, was fractionated into the neutral ethyl acetate fraction, but was not found in the acidic ethyl acetate fraction and in the aqueous residue. At least two active zones were separated on thin layer chromatograms of the ethyl acetate extracts from the filtrate and the methanol extract, and the relative flow‐rates of each active zone from these two sources were very similar. The evidence described above indicates that specific inhibitors of archegonial differentiation may be produced in the tissue of prothallia of Lygodium and eventually be secreted to the medium.

Inhibitors of Aquatic Hyphomycetes in Dead Conifer Needles

SUMMARYNeedle powders of Pinns leucodermis and Sequoia gigantea were extracted with petroleum ether, ethanol, methanol, or distilled water. After evaporating the solvents, extracts, and extracted powder were added to nutrient medium to examine their effect on linear expansion of five aquatic Hyphomycetes. All extracts depressed fungal growth, the inhibition being strongest with the two alcoholic extracts. The FeC13 test indicated phenolic compounds in the alcohol and water but not in the petroleum-ether extracts. There was no correlation between the colorimetrically determined phenol content of an extract and its antifungal activity. Untreated needle powder strongly inhibited fungal growth, as did petroleum- ether or water-extracted powder. By contrast, alcohol-extracted powder did not inhibit fungal growth. The inhibitory effect of methanol extract was much more pronounced at a pH range of 4.0-4.5 than at 5.5-6.5.