Exploration of secondary metabolite profile in the n-hexane fraction of Rhizophora mucronata, Avicennia marina, and Sonneratia alba

Indonesia is a maritime and archipelagic country with an ocean area of almost two-thirds of its total area, with a coastline stretching 99.123 km from Sabang to Merauke. According to Indonesian Law Number 1 of 2014, it is mentioned that one of the most important biological resources of the coast is mangroves. Some mangrove species commonly found on Lombok Island are Rhizophora mucronata, Sonneratia alba, and Avicennia marina. However, there has not been much exploration of the compound content in these mangroves. Therefore, this study aimed to identify the secondary metabolites of the n-hexane fraction of the three mangrove species using Gas Chromatography-Mass Spectrometry (GC-MS). The leaves of each mangrove species were extracted by sonication method using 96% ethanol solvent, followed by multistage fractionation using n-hexane and water. GC-MS analyzed the n-hexane fraction of each mangrove species. The GC-MS analysis revealed that in the n-hexane fraction of mangrove leaves Rhizophora mucronata and Avicennia marina there were 10 compounds, while Sonneratia alba obtained five compounds. The compounds with the highest intensity in the n-hexane fraction of mangrove leaves of Rhizophora mucronata, Sonneratia alba, and Avicennia marina were squalene (41.71%), ethyl oleate (87.53%), and ethyl oleate (44.02%), respectively. Squalene was reported to have antioxidant and anticancer activities. The ethyl oleate was reported to have bactericidal activity on gram-positive and negative bacteria. The three types of mangrove leaves can be an alternative source of medicine