The aim of utilization of water extract of A. flava as a food additive in the production process of palm sugar is to
inhibit the growth of microorganisms which may lower the pH value of the palm sap. To evaluate the antimicrobial
activity of this extract zone of inhibition (mm) was used as a parameter of the antimicrobial activity. The results of
antimicrobial activities are given in Table 1. It is very clear that water extract of A. flava have shown antimicrobial
activity against all tested organisms. Zone of inhibitions exhibited by the extracts with more than 2% of
concentration were not significantly different each other, extending from 15.08 to 19.78 mm.
Therefore, application of the extract with the lowest concentration (2%) is recommended for the effectiveness.
Using bioassay-guided chemical investigation, Keawpradub et al. [9] found that berberine is the main active
compound of A. flava. Yu et al. [10], reported that berberine showed antimicrobial activity against all tested strains
of MRSA (methicillin-resistant Staphylococcus aureus). Berberine has been also reported to possess several
biological activities such as antifungal [11], antimalarial [12], anticancer [13], and also anti-inflammatory [14