Antibacterial Activity of Red Dragon Peel (Hylocereus polyrhizus) Pigment

摘要

Red dragon fruit (Hylocereus polyrhizus) is a species of plant that provides natural pigment which is betalain. Betalain is a one of the pigments that gives a natural colour to flowers and fruits. Moreover, of betalain in red dragon fruit peel, there are bioactive compound such as polyphenol and flavanoid with antioxidant and antibacteria activities. This research was objected to extract pigments and others secondary metabolites from red dragon fruit peel using ethanol, methanol, dicloromethane and ethyl acetate solvents, continued with determined potential antibacteria activity using Resazurin Microtitter Assay (REMA) method. The results of antibacterial activity showed inhibition percentage against test of positive Gram bacteria Streptococcus aureus ATCC 29213 with extract of n-haxane, ethyl acetate and pigment sequentially were 67.5, 67.0, 85.1, 83.1 % and Bacillus subitilis ATCC 11774 were 73.4, 98.6, 97.1, 100 % and negative Gram bacteria Escherichia coli ATCC 35218 were 70.0, 73.1, 74.2, 94. 9 % and Vibrio algynolyticus were 72.6, 73.1, 74.2, 94.9 % at final concentration of 20 μg/mL.