New alkaloids from Casimiroa edulis fruits and their pharmacological activity

The extract of Casimiroa edulis was investigated for antihypertensive activity. The ethanol and total alkaloids (in chloroform) extracts were found to have antihypertensive properties at doses of 500 and 200 mg/kg, respectively. Four quinolinone alkaloids were isolated and identified as: 2-(2'-hydroxy-4'-methoxyphenyl)-5,8-dimethoxy-3-propyl-1H-quinolin-4-one (1), 5,8-dimethoxy-2-(3'-methoxyphenyl)-3-propyl-1H-quinolin-4-one (2), 5,8-dimethoxy-2-(3',4'-dimethoxyphenyl)-3-propyl-1H-quinolin-4-one (3), and 5,6-dimethoxy-2-(2',5',6'-trimethoxyphenyl)-1H-quinolin-4-one (4). Interestingly, compounds 1, 2, and 3 were found to be new alkaloids. The four isolated alkaloids showed antihypertensive activity at doses of 50, 100, 200, and 300 mg/kg, respectively.