Antianxiety activity guided isolation and characterization of bergenin from Caesalpinia digyna Rottler roots.

ETHNOPHARMACOLOGICAL RELEVANCE: Caesalpinia digyna Rottler (Caesalpiniaceae) roots have been used traditionally for soothing nerves, as nervine tonic and febrifuge. The aim of the present study was to isolate the antianxiety constituent(s) from C. digyna roots following bioactivity guided fractionation approach.

MATERIAL AND METHODS: Bioactive fraction F4 was subjected to column chromatography to get three sub-fractions (F4.1-F4.3) and a compound CD2. CD1 and CD2 were characterized using standard spectral techniques. Three fractions (F4.1-F4.3) were evaluated for antianxiety activity in mice using EPM. An effective dose of the antianxiety principle was optimized, and its activity was, further evaluated using open field and mirror chamber tests.

RESULTS: CD1 and CD2 characterized as bergenin, exhibited significant antianxiety activity at 80mg/kg, po which was statistically comparable to that of diazepam (2mg/kg, po). However, F4.1-F4.3 were observed to be devoid of antianxiety activity. Bergenin also exhibited significant antianxiety activity in open field and mirrored chamber tests.

CONCLUSIONS: Bergenin, isolated from roots of C. digyna, exhibits significant antianxiety activity at 80mg/kg, po in three different models for evaluating antianxiety activity. This activity of bergenin is being reported for the first time.