Trichosanates A-G and cucurbitacins W-Y, anticomplement monoterpenoids and cucurbitane-type triterpenoids from the pericarps of Trichosanthes kirilowii

The pericarps of Trichosanthes kirilowii are often used to treat cough in traditional Chinese medicine, and its ethanol extract exhibited effective therapeutic effects on acute lung injury (ALI) in vivo caused by H1N1. An anticomplement activity-guided fractionation on the extract resulted in the isolation of ten new terpenoids, including seven monoterpenoids, trichosanates A-G (1-7), and three cucurbitane-type triterpenoids, cucurbi-tacins W-Y (8-10), as well as eleven known terpenoids (11-21). The new terpenoids' structures were determined by spectroscopic analysis, X-ray crystallographic analysis (1), electronic circular dichroism (ECD) analysis and calculations (2-10). Twelve monoterpenoids (1-7 and 11-15) and five cucurbitane-type triterpenoids (8-10, 18, and 20) exhibited anticomplement activity in vitro. For the monoterpenoids, the long aliphatic chain substituents might enhance their anticomplement activity. Additionally, two representative anticomplement terpenoids, 8 and 11, obviously attenuated H1N1-induced ALI in vivo by inhibiting complement overactivation and reducing inflammatory responses.

Automated summary

The pericarps of Trichosanthes kirilowii are traditionally used to treat cough. Its ethanol extract has shown effective therapeutic effects on acute lung injury caused by H1N1. A study on the extract resulted in the discovery of ten new terpenoids, including seven monoterpenoids and three cucurbitane-type triterpenoids, as well as eleven known terpenoids. Among these compounds, twelve monoterpenoids and five cucurbitane-type triterpenoids exhibited anticomplement activity in vitro. Two representative terpenoids, 8 and 11, significantly attenuated H1N1-induced acute lung injury in vivo by inhibiting complement overactivation and reducing inflammatory responses.