Chemical constituents from the stems of Tinospora sinensis and their anti-inflammatory activities.

Phytochemical investigation of the stems of Tinospora sinensis yielded forty-nine compounds, including seven previously undescribed clerodane diterpenoids (1-7), three rare rearranged cadinane-type sesquiterpenoids (8-10, with 9 and 10 being previously unreported and 8 isolated from a plant for the first time), and forty-four known compounds (11-49). Structures of 1-10 were characterized by IR, HRESIMS, NMR, and computational CD analysis. The isolates were screened for anti-inflammatory effects in LPS-stimulated RAW264.7 macrophages via a nitric oxide (NO) inhibition assay. Compound 43 demonstrated the strongest activity, with an IC50 of 9.81 μM. Mechanism studies showed that compound 43 attenuates NO production through both direct inhibition of iNOS enzyme activity and NF-κB-mediated suppression of iNOS expression.