Supaluk PrachayasittikulPatumporn ManamManeekarn ChinworrungseeChartchalerm Isarankura-Na-ayudhyaSomsak RuchirawatVirapong PrachayasittikulSrinakharinwirot UniversityMahidol UniversityChulabhorn Research Institute2018-09-132018-09-132009-11-01Molecules. Vol.14, No.11 (2009), 4414-4424142030492-s2.0-73349142009https://repository.li.mahidol.ac.th/handle/20.500.14594/27392This study investigated bioactive extracts of Polyalthia debilis (Annonaceae) with antimicrobial, antimalarial and cytotoxic activities. Extensive chromatographic isolations provided azafluorenone alkaloids; onychine (1) and 7-methoxyonychine (2) together with a mixture of β-sitosterol and stigmasterol. The two alkaloids were isolated from the P. debilis for the first time. Isolated fractions containing a mixture of triterpenoids (C7, C8 and C9) exhibited the most potent antimicrobial activity against many bacterial strains with minimum inhibitory concentration of 64 μg/mL. Fractions with antimalarial and cytotoxic activities were also observed. The findings suggest the potential use of P. debilis in medicinal applications.Mahidol UniversityChemistryArticleSCOPUS10.3390/molecules14114414