Comparison of in-vitro antimicrobial activities and selected properties of Acacia nilotica seed extract and its formulated oral capsules dosage form

Background: The antimicrobial properties of Acacia nilotica seeds extract (ANSE) has been demonstrated in few studies. This property may be affected when the extract is formulated into modern dosage form which involves a number of formulation processes.

Objectives: This study was carried out to evaluate and compare the in-vitro antimicrobial activities of ANSE and its formulated capsules against some commonly implicated organisms in the gastrointestinal tract.

Methods: Seeds of Acacia nilotica obtained from Ilorin were prepared and extracted with absolute methanol. An oral capsule formulation was designed for the extract. in-vitro antimicrobial activities of the extracts and formulated capsules were carried out on four test organisms including Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. This was done using the pour plate method. Physical properties and the flow properties of both the crude extract and formulated capsules were also determined and compared using official standards.

Results: There was no marked difference between the colour, taste and odour of ANSE and formulated granules for oral capsules. There was a decrease in moisture content and pH of ANSE after formulation into granules. The flow properties of the crude extract revealed a poor flow which improved after extract was formulated into granules. The methanol extract exhibited antimicrobial activities against test organisms pre- and post-granulation/ encapsulation and activity was not significantly affected by the encapsulation processes (p>0.05).

Conclusion: Granulation of ANSE before encapsulation improved its flow properties. The formulation of ANSE into oral capsule dosage form did not significantly affect its antimicrobial activities.