A stabilized flavonoid glycoside in heat-treated Cassia alata leaves and its structural elucidation.

Heat-treated leaves of Cassia alata were studied for any change in chemical constituents using sun dried leaves as the reference standard. A high concentration of a constituent was observed in the heat-treated leaves. Spectroscopic studies revealed the structure of the constituent as kaempferol 3-gentiobioside, which has not yet been detected in the Cassia species. In a stability study disappearance of kaempferol 3-gentiobioside was noted in the sun dried leaves while there was little or no change in the kaempferol 3-gentiobioside concentration in the heat-treated leaves when incubated in an aqueous solution, suggesting a possible presence of enzymatic activities in the sun dried leaves. Therefore, heat-treatment may be a good method to stabilize kaempferol 3-gentiobioside in Cassia alata leaves.