[Chemical studieson hydrophilic constituents of toad skin]

Fifteen compounds were isolated from the toad skin by a combination of various chromatographic methods including macroporous resin, silica gel, ODS and semi-preparative HPLC. Their structures were identified as 4,5-dimethyl-1,3,4,5-tetrahydropyrrolo[4,3,2-de]quinolin-6-ol(1), serotonin(2), N-methyl serotonin(3), O-methyl bufotenine(4), 1,2,3,4-tetrahydro-6-hydroxy-β-carboline(5), O-methylserotonin(6), glycinebetaine(7), caffeine(8), bufotenine(9), shepherdine(10), tryptophan(11), (5-hydroxy-1H-indol-3-yl)acetic acid(12), 5-hydroxy tryptophol(13), 2-methyl-6-hydroxy-1,2,3,4-tetrahydro-β-carboline(14), bufothionine(15). Among them, compound 1 was a new compound,compound 5 was a new natural product. Compounds 4-8 and 10-14 were separated from toad skin for the first time.