Chikara IchinoHiroaki KiyoharaNoppamas SoonthornchareonnonWongsatit ChuakulAki IshiyamaHitomi SekiguchiMiyuki NamatameKazuhiko OtoguroSatoshi OmuraHaruki YamadaKitasato UniversityThe Kitasato InstituteMahidol University2018-08-202018-08-202006-06-01Planta Medica. Vol.72, No.7 (2006), 611-614003209432-s2.0-33745726233https://repository.li.mahidol.ac.th/handle/20.500.14594/22892During the screening of antimalarial substances, the 80% EtOH extract from the outer bark of Ochna integerrima Merr. (Ochnaceae) was shown to have a good anti-malarial activity (IC50 value: 6.5 μg/mL) whereas extracts from the inner barks of O. integerrima showed no antimalarial activity. Biflavanone (1), which had not been found previously from a natural plant source, was isolated as a potent antimalarial active ingredient (IC50 value: 80 ng/mL) from the extract of the outer barks. The stereoisomer of 1 (= compound 2) was also isolated from this plant; however, its activity was significantly lower than that of 1. © Georg Thieme Verlag KG Stuttgart.Mahidol UniversityAgricultural and Biological SciencesChemistryPharmacology, Toxicology and PharmaceuticsArticleSCOPUS10.1055/s-2006-931569