Search

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 values of liriodenine against the white-rot fungi Lenzites betulina and Trametes versicolor were 0.76 and 3.50 μg/mL, respectively. IC values of liriodenine against the brown-rot fungi Laetiporus sulphureus, Gloeophyllum trabeum, and Fomitopsis pinicola were all lower than 2.0 μg/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. [ABSTRACT FROM AUTHOR]

Resistance to conventional fungicides causes the poor disease control of agriculture. Natural products from plants have great potential as novel fungicide sources for controlling pathogenic fungi. In this study antipathogenic activity of the leaf essential oil and its constituents from Calocedrus macrolepis var. formosana Florin were evaluated in vitro against six plant pathogenic fungi. Chemical analysis of leaf oil by GC/MS allowed identification of α-pinene (44.2%), limonene (21.6%), β-myrcene (8.9%), β-caryophyllene (8.2%), caryophyllene oxide (2.4%), α-cadinol (1.6%), β-pinene (1.2%), and T-muurolol (1.1%) as main components. Sesquiterpenoid components of the oil were more effective than monoterpenoid components of the oil. In particular, T-muurolol and α-cadinol strongly inhibited the growth of Rhizoctonia solani and Fusarium oxysporum, with the IC50 values<50μgml−1. These compounds also efficiently inhibited the mycelial growths of Colletotrichum gloeosporioides, P. funerea, Ganoderma australe and F. solani. These results showed that T-muurolol and α-cadinol possess antifungal activities against a broad spectrum of tested plant pathogenic fungi and could be used as potential antifungal agents for the control of fungal diseases in plants. [Copyright &y& Elsevier]