Inhibitors of Aquatic Hyphomycetes in Dead Conifer Needles

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Abstract
Needle powders of Pinus 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 5 aquatic Hyphomycetes [Anguillospora pseudolongissima, Clavariopsis aquatica, Lemonnlera aquatica, Tetracladium marchalianum and Tricladium angulatum]. All extracts depressed fungal growth, the inhibition being strongest with the 2 alcoholic extracts. The FeCl3 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.