Next, the inhibitory effect of the plant extracts on TNF-α synthesis was investigated. The highest inhibition of TNF-
α was observed in the PBMC treated with 50 μg/ml of G mangostana extract (94.59%). The other plant extracts at the
same concentration also showed high inhibitory activity against TNF-α production (more than 70% inhibition). In
addition, the results also showed that the extracts of G. mangostana, E. odoratum, H. cordata, and S. siamea showed
the potent inhibition on TNF-α in dose-dependent manner.