Development of microspheres containing Cassia alata extract

Abstract

Senna alata or Cassia alata (C. alata) is a plant belonging to the family Leguminosae and has been documented to have antifungal and antimicrobial activities. This research aims to extract C. alata using known extraction procedure, and to find optimum condition for microencapsulation by employing double emulsion solvent evaporation method. Biodegradable poly (D, L-lactide-co-glycolide) (PLGA) was the polymer of interest to encapsulate the C. alata extracts owing to its ability to give a controlled-release profile. Resultant microspheres were characterized for size distribution and external morphology by laser diffraction technique and scanning electron microscopy, respectively. Encapsulation efficiency (EE) was also calculated and the C. alata was quantified by UV absorbance. Several parameters have been investigated to optimize the characteristic of fabricated microspheres during the preparation process including different homogenization times for the primary emulsion, different volume ratios of aqueous/oil phases, several types and concentrations of surfactants, co-solvent in aqueous or oil phase and buffer systems (at varying pH and different concentrations of PBS). It was found that, most of the parameters employed resulted in low EE (<11%), however the encapsulation efficiency (64%) was significantly improved when the hardening tank is buffered to pH 7, with minimal effect on particle size. The particle size range obtained was between 6-30 ?m. Subsequent in vitro analysis displayed usual release pattern attributed to PLGA that is initial burst release followed by a gradual release phase up to the period of study. Although our C. alata extract did not show antimicrobial and antifungal activities against various strains tested but it appeared active against Escherichia coli. It is hereby suggested that our C. alata microspheres may be useful as preservative and antidote related to food-poisoning commonly caused by Escherichia coli.