Interaction Between Apigenin, Kaempferol and Trans-Cinnamic Acid: The Compounds Contributed to the Xanthine Oxidase Inhibitory Activity of Chrysanthemum morifolium.

Chrysanthemum morifolium is commonly prescribe as one of the ingredients in traditional Chinese medicine for gout treatment and pain relief from gout. This study aimed to study the interaction between apigenin, kaempferol and trans-cinnamic acid identified from C. morifolium in xanthine oxidase (XO) inhibition. In our previous study, apigenin, kaempferol and trans-cinnamic acid have been shown to inhibit XO. In this study, an interaction assay showed that apigenin and kaempferol exhibited an additive effect, while trans-cinnamic acid exhibited an antagonistic effect against apigenin (or kaempferol) in XO inhibition. In conclusion, the additive effect of apigenin and kaempferol at the 8.2:2.7 ratio was responsible for the XO inhibitory effect of C. morifolium extract. Future study using the combination of apigenin and kaempferol for XO inhibition in the ratio similar to their natural composition in C. morifolium is recommended. The additive effect of these two compounds, each used at lower dose, could be beneficial due to its enhanced effectiveness and reduced negative impacts.