Investigation, collation and research of traditional Dai medicine of China A new 8-O-4‘-neolignan from stem barks of Lindera caudata and its cytotoxicity A new 2-arylbenzofuran from twigs of Cassia alata and its cytotoxicity Research status, development and utilization of traditional Dai medicine in China A new furan-2-carboxylic acid from stem bark of Cassia alata