Figure 2. Chemical structures of four representative bioactive compounds isolated from natural plant extracts are shown.
Triptolide: a diterpene isolated from Tripterygium wilfordii, Curcumin: a polyphenol isolated from Curcuma longa, epigallocatechin-3-gallate (EGCG): a flavonoid from Camellia sinensis, and acetyl-11-keto-beta-boswellic acid (AKBA): an organic acid from Boswellia serrata. These natural compounds possess anti-inflammatory activity that can suppress autoimmune arthritis.