Ursolic acid: a potent inhibitor of superoxides produced in the cellular system.

Triterpenoids of ursane class: ursolic acid, ilelatifol D, corosolic acid and euscaphic acid were isolated for the first time from Leonurus cardiaca, a member of the family Lamiaceae. The isolated compounds were tested for their cell-based antiinflammatory potential by suppressing respiratory burst activity and superoxide scavenging property by using xanthine/xanthine oxidase system to produce superoxides in the cell-free system. Ursolic acid was found to be an excellent inhibitor for the superoxides produced in the cellular system, while the same was inactive in the superoxide scavenging activity in cell-free system.