Anti-inflammatory activity of Curcuma wanenlueanga Saensouk, Thomudtha & Boonma rhizomes and the search for its bioactive markers by harmonizing bioassay-guided isolation and network pharmacology.

BACKGROUND: Rhizomes of Curcuma wanenlueanga Saensouk, Thomudtha & Boonma have been used in Thai traditional medicine and are included as an ingredient in a Thai traditional liniment formula listed by the Ministry of Public Health of Thailand for treating symptoms related to joints and muscle inflammation. However, anti-inflammatory activity and bioactive constituents of C. wanenlueanga have not yet been investigated. Thus, this study aimed to investigate the anti-inflammatory activity and underlying mechanism of C. wanenlueanga rhizome extract and its responsible bioactive components. METHODS: The fractionation of bioactive compounds from C. wanenlueanga extract was guided by antioxidant activity on DPPH and Griess assays, and anti-inflammatory activity on LPS-induced RAW 264.7 cells. The biological activities of isolated compounds were first predicted by network pharmacology and further confirmed in cell-based assay with LPS-induced RAW 264.7 cells and enzyme-linked immunosorbent assay (ELISA) of tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6). RESULTS: The ethanolic extract of C. wanenlueanga rhizomes was proved to show anti-inflammatory activity on LPS-induced RAW 264.7 cells. Three curcuminoids including curcumin (1), demethoxycurcumin (2), dihydrodemethoxycurcumin (3), and two sesquiterpenoids, namely curcumenone (4), and zedoarondiol (5) were separated from anti-inflammatory fractions of C. wanenlueanga extract. The anti-inflammatory activity of these compounds to attenuate the productions of TNF-α and IL-6 was predicted by pharmacological network. The inflammatory assays, including the Griess assay for NO and ELISA for TNF-α and IL-6, confirmed that all isolated compounds reduced the production of these inflammatory mediators. CONCLUSION: The present study shows the accordance between the results from pharmacological network and cell-based assays, which indicate the anti-inflammatory activity of C. wanenlueanga rhizomes and their bioactive constituents. This suggests the potential of bioactive compounds 1-5 to be used for quality assessment of C. wanenlueanga extract in the development of herbal products.