Advances in studies on resources for medicinal source plants with bergenin Bergenin HPLC Determination of Two Species of Bergenia growing in Tibet Comparative studies on content of arbutin, bergenin and catechin in different part of Bergenia purpurascens and B. crassifolia Research on growth state and physiological changes of Tianquan Bergenia purpurascens under different shade conditions Comparison of arbutin contents from Bergenia purpurascens in Yunnan