Sesquiterpenoids from Ainsliaea spicata and their cytotoxic and NO production inhibitory activities

•Four new sesquiterpenes (1–4) were isolated from Ainsliaea spicata.•Forty known sesquiterpene (5–44) were also isolated from Ainsliaea spicata.•All isolates were evaluated for cytotoxicity against three human tumor cell lines.•Compounds 7 and 38 showed selective cytotoxicity against human tumor cells.•Compounds 1–4 were evaluated for NO production-inhibitory activities.