DOI: 10.36347/sajb.2021.v09i08.006

Pages: 215-222

Skin disease is one of the most common diseases in tropical countries such as Indonesia, which might be caused by infection of pathogens like Staphylococcus aureus and Pseudomonas aeruginosa. Red algae Gracilaria sp. originated from Wediombo Beach, Yogyakarta, Indonesia has not been widely used for medicinal purpose, especially as an antimicrobial for skin diseases in human. Therefore, this research aimed to study about the potency of local Gracilaria sp. extract as an antibacterial against skin disease pathogen. Red algae extraction was carried out using maceration method in ethanol solvent. Identification of phytochemical groups was determined using basic biochemistry analysis and Thin Layer Chromatography (TLC), while active phytochemical compounds were identified using Gas Chromatography-Mass Spectrophotometry (GC-MS). Antibacterial tests were performed by minimum inhibition concentration (MIC) using MTT indicator and inhibition assay using paper disc method. Alkaloids and saponins were identified in phytochemical based on biochemical tests. Compound separation by TLC using chloroform and methanol solvents with a ratio of 90:10 resulted in seven color spots with ninhydrin spray and six color spots with anisaldehyde spray. The GC-MS results showed that there were 38 compounds identified in the crude extract, which 8 of these 38 compounds are known to have anti-bacterial activity. Anti-bacterial assay of Gracilaria sp. extract on concentration of 100% showed medium strength to inhibit Staphylococcus aureus and strong strength to inhibit Pseudomonas aeruginosa. Crude extract of local Gracilaria sp. is potential to be used as antimicrobials against Staphylococcus aureus and Pseudomonas aeruginosa common agents for skin disease.