Detection of Anti-Fungal Sapwood Extractives in Non-Durable Scots Pine (Pinus sylvestris), Rubberwood (Hevea brasiliensis) and Jelutong (Dyera costulata)
A general laboratory bioassay method of Woodward and Pearce (1985) was adopted to detect anti-fungal activity of sapwood or heartwood extractives of 5 Malaysian hardwoods [dark red meranti heartwood (Shorea spp.), red balau heartwood (Shorea spp.), kulim heartwood (Scorodocarpus borneensis), jelu...
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| Main Authors: | , |
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| Format: | E-Article |
| Language: | English |
| Published: |
IRGWP
2007
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| Subjects: | |
| Online Access: | http://ir.unimas.my/id/eprint/16025/1/Detection%20of%20anti-fungal%20sapwood%20extractives%20%28abstract%29.pdf http://ir.unimas.my/id/eprint/16025/ https://www.researchgate.net/publication/291728840 |
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| Summary: | A general laboratory bioassay method of Woodward and Pearce (1985) was adopted to detect
anti-fungal activity of sapwood or heartwood extractives of 5 Malaysian hardwoods [dark red
meranti heartwood (Shorea spp.), red balau heartwood (Shorea spp.), kulim heartwood
(Scorodocarpus borneensis), jelutong sapwood (Dyera costulata) and rubberwood sapwood
(Hevea brasiliensis), including the temperate Pinus sylvestris (Scots pine sapwood). The
heartwoods of these species and Scots pine sapwood are known to be highly resistant to decay by
soft-rotting Ascomycetes and anamorphic fungi (about 1-7% wood mass loss), while the
sapwoods of rubberwood and jelutong had much reduced soft rot resistance (respectively 35,
32% wood mass loss) but obviously prone to sapstain and mold attack, including that of Scots
pine. Crude methanol extracts of woodmeal samples of each wood species were loaded on to
thin-layer chromatography plates at between 0.003 and 0.1 g fresh mass equivalent of woodmeal
per spot so as to optimize resolution of separated compounds, and developed with
chloroform:methanol solvent (ratio 19:1). The dried plates were sprayed with fresh fungal spores
of Cladosporium cucumerinum and incubated at >90% RH for 5 days in the dark. Presence of
anti-fungal compounds was revealed by white regions along the solvent transect for each extract
of each species where inhibited spore germination and mycelial growth of C. cucumerinum
occurred. Comparisons of anti-fungal activity of extracts between species and between sapwood
and heartwood were made. Results revealed that several zones of inhibitory activity, indicated by
their Rf-values, were clearly visible on chromatographic separations of methanol extracts of
these 5 wood species. The inhibitory zones for 2 heartwood extracts (except kulim) did not move
from the origin which was also resistant to infection. However inhibition zones were also
detected for the sapwoods of rubberwood, jelutong and Scots pine against C. cucumerinum
despite the known sapstain and decay susceptibility of these wood substrates. The presence of
hitherto unidentified anti-fungal compounds in the sapwoods of these species may elicit limited
potency or narrow spectrum protection from fungal infection and onset of stain or decay. |
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