Mammea B/BA Isolated From the Seeds of L. (Calophyllaceae) is a Potent Inhibitor of Methicillin-Resistant .

remains a pathogen of high concern in public health programs worldwide due to antibiotic resistance and emergence of highly virulent strains. Many phytochemicals have demonstrated activity against and other Gram-positive bacteria, but the minimum inhibitory concentration (MIC) values comparable to commonly used antibiotics are needed. In the present study, bio-guided fractionation of the ethanol extract of seeds of L. (Calophyllaceae) throughout the antibacterial activity, against strains that are sensitive and resistant to methicillin, led to the isolation of four coumarins identified as mammea B/BA, mammea B/BC, mammea A/AA cyclo D and mammea A/AA cyclo F, and a mixture of mammea B/BA cyclo F plus mammea B/BD cyclo F. The extract inhibited the growth of with MIC values of 2-4 μg/ml and Mammea B/BA (MaBBA) presented MIC values in a range between 0.5 and 1.0 μg/ml in six methicillin-sensitive strains and eight methicillin-resistant strains evaluated. We consider MaBBA the most potent of all mammea coumarins reported to date, according to the literature review carried out at the time of writing of this article. Toxicity assessment against the nematode and against human fibroblasts of the extract and the compound MaBBA indicated that both had low toxicity.