Seasonal analysis from the antimicrobial potency and flavonoid and quinone content from Aloe arborescens Mill., xanthorrhoeaceae, leaf extracts

Abstract

This work has the objective of evaluate the antimicrobial potency and the content of flavonoids and quinones from the Aloe arborescens Mill., Xanthorrhoeaceae, leaf extracts produced in the four seasons of the year. Ethanol and chloroform extracts were prepared from the leaves, the bioassays from antimicrobial activity were developed by the macrodilution method in broth, and dosages of flavonoids and quinones were performed in the extracts. The winter chloroform extract showed the lowest CIM (128 μg/mL) on B. subtilis. The ethanol extract showed the lowest CIM (256 μg/mL) and the lowest CMM (512 μg/mL) on K. pneumoniae. The summer and fall ethanol extracts showed low antimicrobial activity. The quinones extracts showed inhibitory activity on the tested microorganisms. The winter, spring and summer chloroform extracts showed higher antimicrobial activity compared to the fall chloroform one. The winter ethanol extract content from the leaves were higher in the hotter periods of collection (summer and fall) and the flavonoids content were similar in the four collection periods.