Agilawood is a costly heartwood medicine obtained from Aquilaria sinensis with active ingredients mainly composed of volatile and semi-volatile substances. However, the formation time of agilawood is quite long and little is known about its formation mechanism. Two highly active fungi obtained from natural agilawood were inoculated on A. sinensis trees to understand their interaction processes and elucidate the transformation rules of induced chemical compositions within different test periods. The results demonstrated that the fungi could successfully colonize living tissues and cells and activate the host defense system, resulting in agilawood accumulation. With increasing time, the main components of A. sinensis converted into constituents or analogs of agilawood and the host exhibited "self-injury" to prevent fungal intrusion and protect other tissues. The data presented here could provide scientific basis for producing agilawood with the two new fungi in a safe, feasible, and sustainable manner without destroying rare Aquilaria plants.
CUI JinLongGUO ShunXingFU ShaoBinXIAO PeiGenWANG MengLiang
The aim of this study was to establish a method for discriminating Dendrobium officinale from four of its close relatives Den- drobium chrysanthum, Dendrobium erystallinum, Dendrobium aphyllum and Dendrobium devonianum based on chemical composition analysis. We analyzed 62 samples of 24 Dendrobium species. High performance liquid chromatography analysis confirmed that the four low molecular weight compounds 4＇,5,7-trihydroxyflavanone （naringenin）, 3,4-dihydroxy-4＇,5-dime- tboxybibenzyl （DDB^2）, 3＇,4-dihydroxy-3,5＇-dimethoxybibenzyl （gigantol）, and 4,4＇-dihydroxy-3,3＇,5-trimethoxybibenzyl （moscatilin）, were common in the genus. The phenol-sulfuric acid method was used to quantify polysaccharides, and the mon- osaccharide composition of the polysaccharides was determined by gas chromatography. Stepwise discriminant analysis was used to differentiate among the five closely related species based on the chemical composition analysis. This proved to be a simple and accurate approach for discriminating among these species. The results also showed that the polysaccharide content, the amounts of the four low molecular weight compounds, and the mannose to glucose ratio, were important factors for species discriminaut. Therefore, we propose that a chemical analysis based on quantification of naringenin, bibenzyl, and polysaccha- rides is effective for identifying D. officinale.
