Antioxidant and antibacterial activity of ethanol extract from gynocthodes sublanceolata

This thesis was conducted to investigate antioxidant and antibacterial activity of ethanol extract of G. sublanceolata (pitang leaves) for a potential as natural food colouring agent that has antioxidant and antibacterial activites. Pitang leaves were separated from the branches and the fruits, then, extracted using ethanol. Pitang leaves that were grinded and mixed with ethanol have been soaked in sonicator for 20 minutes at temperature of 20° C. This method was repeated three times to obtain the extracts. Then, the extract has been subjected through the process of evaporation to collect the sample. The sample is in the form of 1/3 dried. This means that the samples collected are still in a liquid state. Anthocyanin was detected in pitang leaves responsible for producing the color purple in the leaf extract. Features such as antioxidant activity can be detected by DPPH free radical scavenging assay. Based on this study, the sample obtained does not exceed the standard of IC₅₀. This might due to the low antioxidant content. To validate this finding, another test for the chemical profiles of the samples was conducted by using thin layer chromatography - DPPH test. The result indicates that the yellow spot appears faintly. However, extracts of G. sublanceolata shown the growth inhibition of Escherichia coli and Staphylococcus aureus proved by using the paper disc diffusion method. Based on the tests performed, the extract of G. sublanceolata indicates the presence of antimicrobial activity against gram-positive bacteria and gram negative.