Antimicrobial activities of extract, fractions and isolated compounds from the fruits of Elaeocarpus floribundus growing in North-East India

Background: The fruits of Elaeocarpus floribundus Blume are edible and used for the treatment of dysentery and diarrhoea, a claim of which no scientific studies have validated and whose bioactive principles are unknown. Therefore, the present study centres in the evaluation of the antimicrobial activity of the ethanolic crude extract, fractions and the identification of its active constituents. Methods: The antimicrobial activity of the crude extract, fractions and the isolated compounds were determined using the broth microdilution method. Folin-Ciocalteu and aluminium chloride assays were utilized to determine the total phenolic and flavonoid contents. Respectively, while the essential minerals were determined using an atomic absorption spectrometer. Results: The crude extract exhibited significant antimicrobial activity, while the ethyl acetate fraction was the most active against the microorganisms among the fractions. The purification of this bioactive fraction yielded seven compounds which are reported for the first time from this source. Dibutyl succinate (1) exhibited the highest growth inhibitory activity with MIC values of 60, 80, 90 mu g/mL against S. dysenteriae, C. albicans, and B. subtilis, respectively. The elemental analysis of the fruit revealed it to be a good source of essential elements. Conclusion: This study indicates that dibutyl succinate (1) can be considered as the main bioactive compound in the fruits of E. floribundus. Therefore, it can be further studied for the treatment of diarrhoea in vivo. These results thereby affirm the traditional uses of the fruits of E. floribundus.

Automated summary

The study found significant antimicrobial activity in the fruits of Elaeocarpus floribundus, with the ethyl acetate fraction showing the highest activity against microorganisms and yielding seven previously unreported compounds. Dibutyl succinate exhibited the highest growth inhibitory activity, and the fruit was found to be a good source of essential elements.