Megastigmane sesquiterpenoids from the pericarps of Trichosanthes kirilowii and their anti-complementary and anti-inflammatory activities.

The pericarps of Trichosanthes kirilowii Maxim. (T. kirilowi) have been traditionally used in Chinese medicine for their heat-clearing properties. This study employed anti-complementary activity-guided fractionation and purification to isolate eleven compounds from the pericarps of T. kirilowi, including two new megastigmane sesquiterpenoids (6, 8), seven previously identified megastigmane sesquiterpenoids (1-5, 7, 9), and two known flavonoids (10,11). The structures were elucidated using spectroscopic techniques (NMR, HRESIMS, IR, and UV) and computational chemistry methods with CD spectroscopy. Biological evaluation demonstrated that four megastigmane sesquiterpenoids (3, 4, 5, 6) and two flavonoids (10, 11) exhibited both anti-complementary activities (CH values ranging from 0.906 ± 0.075 mM to 4.933 ± 0.318 mM) and anti-inflammatory activities (inhibition rates: 14.30 ± 4.234 % to 72.87 ± 1.594 %). Furthermore, the new megastigmane sesquiterpenoid (6), featuring a 3-hydroxy-3-methylglutaryl (HMG) substituent, and the flavonoid glucoside (11) modulated cytokine levels in LPS-stimulated ANA-1 cells by reducing IL-6 and MCP-1 while increasing IL-10.