Wood-rotting fungi lead to great economic losses of lignocellulosic materials. The influence of extractives on the decay resistance of Michelia formosana wood and the antifungal activities of heartwood extract and its constituent against wood-rotting fungi were evaluated. Results revealed that extractives had a strong influence on the decay resistance of M. formosana heartwood. The unextracted heartwood block was resistant to fungi, while the extracted heartwood block was not. Antifungal activities of ethanolic extract from heartwood were assessed; results revealed that the ethanolic extract possessed good antifungal activity against wood-rotting fungi. The ethanolic extract was further separated into four fractions including n-hexane-soluble fraction, ethyl acetate-soluble fraction, n-butanol-soluble fraction, and water-soluble fraction. Among these fractions, the n-hexane-soluble fraction exhibited the best antifungal ability. An alkaloid, liriodenine, was isolated from the active n-hexane-soluble fraction. IC 50 values of liriodenine against the white-rot fungi Lenzites betulina and Trametes versicolor were 0.76 and 3.50 lg/mL, respectively. IC 50 values of liriodenine against the brown-rot fungi Laetiporus sulphureus, Gloeophyllum trabeum, and Fomitopsis pinicola were all lower than 2.0 lg/mL. Results indicated that liriodenine exhibited a broad spectrum of antifungal activity and great potential to develop as an environmentally benign fungicide for the preservation of lignocellulosic materials.
Michelia formosana (Kanehira) Masamune is a broad-leaved species widespread in East Asia; the wood extract and its constituents possess antifungal activity against wood-decay fungi. Antifungal activities of leaf essential oil and its constituents from M. formosana were investigated in the present study. Bioassay-guided isolation was applied to isolate the phytochemicals from leaf essential oil. 1D and 2D NMR, FTIR, and MS spectroscopic analyses were applied to elucidate the chemical structures of isolated compounds. Leaf essential oil displayed antifungal activity against wood decay fungi and was further separated into 11 fractions by column chromatography. Four sesquiterpenoids were isolated and identified from the active fractions of leaf essential oil through bioassay-guided isolation. Among these sesquiterpenoids, guaiol, bulnesol, and β-elemol have higher antifungal activity against brown-rot fungus Laetiporus sulphureus and white-rot fungus Lenzites betulina. Leaf essential oil and active compounds showed better antifungal activity against L. sulphureus than against L. betulina. The molecular structure of active sesquiterpenoids all contain the hydroxyisopropyl group. Antifungal sesquiterpenoids from M. formosana leaf essential oil show potential as natural fungicides for decay control of lignocellulosic materials.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.