Megistoquinones I and II, two quinoline alkaloids with antibacterial activity from the bark of Sarcomelicope megistophylla

Two alkaloids, megistoquinone I (1) and megistoquinone II (2), were isolated from the bark of Sarcomelicope megistophylla. Their structures have been elucidated on the basis of MS and NMR data. Both belong to quinoline alkaloid series and should be considered as oxidation products of a furo2,3-b]quinoline precursor. The two alkaloids showed antibacterial properties with minimum inhibitory concentration (MIC) ranging from 2.35 to 5.25 mg/ml for 1 and 0.73 to 1.23 mg/ml for 2.