Development and evaluation of andrographolide nanoemulsions for antibacterial activity against Streptococcus sp.

This project aimed to synthesize andrographolide nanoemulsions using a low-energy method and compare their inhibitory effects on Streptococcus sp. between andrographolide nanoemulsions and andrographolide extract. Firstly, andrographolide nanoemulsions were synthesized from andrographolide extract using a low-energy method. Andrographolide extract was mixed with pure virgin coconut oil and Tween 80. The morphology of the andrographolide nanoemulsions was characterized by transmission electron microscopy (TEM), and thin-layer chromatography (TLC) was employed to identify andrographolide. The inhibitory capacity was tested by using the zone of inhibition. The results show the average zone of inhibition is 1.35 ± 0.40 cm for andrographolide nanoemulsions and 0.31 ± 0.25 cm for regular andrographolide extract. It is found that the inhibitory effect on Streptococcus sp. in andrographolide nanoemulsions is more than quadrupled when compared to regular andrographolide extract. Based on the experiment, Tween 80 does not affect antibacterial activity.