The Variation Of Three Triterpenoids In White Birch Bark In Relation To Environmental Factors

White birch (Betula platyphylla Suk.), a deciduous broadleaf tree of Family Betulacea, has abundance of lupane pentacyclic triterpenoids, including betulin, betulin acid, and lupeol. It distributes widely in northeast of China. Due to the bactericide, anti-tumor, anti-inflammatory, and anti-HIV properties of triterpenoids in birch bark, it is a valuable medicinal and economic tree. In the present research, the variation of the concentrations of three triterpenoids in white birch bark in relation to the sites of white birch, the DBH of the tree, the forest type, the altitude, and the stage of succession were investigated.1. The study on the relationship between triterpenoids and tree age showed that betulin concentration positively related to the DBH, when DBH was within1cm to14cm. When the DBH was higher (15cm to33cm), no obvious correlation was found between the concentration of betulin and DBH. There was no apparent correlation between the DBH and the concentrations of betulinic acid or lupeol in white birch bark.2、Analysis by one-way ANOVA showed that there was a significant effect of the forest types on the concentrations of three triterpenoids in white birch bark. The content of betulin and betulinic acid on sunny slope in the pine, birch mixed forest were significantly higher than that of other forest types, and the content of lupeol in the shadow slope of the red-skinned spruce and birch mixed forest was the highest.3、There was a significant influence of the succession stage on the concentrations of betulin and betulinic acid, but no influence on that of lupeol in white birch bark. The concentration of betulin in late stage of succession was the highest, and the content of the betulinic acid in early stage of succession was the highest.4、There was a significant influence of the altitude on the concentrations of betulin and betulinic acid, but no influence on the concentration of lupeol in white birch bark. The concentration of betulin at743m of altitude was the highest, reached260.24mg/g, at1437m of altitude was the lowest, only112.48mg/g. The concentration of betulinic acid at1329m of the altitude was the highest which reached34.72mg/g, and the concentration of betulinic acid was only20.01mg/g (the lowest) at1117m of the altitude.5、The concentrations of three triterpenoids at different geographical locations showed a significant change. Betulin concentration fluctuantly ranged from153.04mg/g to372.47mg/g. Betulin acid concentrations were18.58mg/g-63.75mg/g, and lupeol concentrations was2.26mg/g～6.14mg/g.