Phytochemical diversity, rhodomyrtone content, nutrient content, and antioxidant efficacy in keramunting leaves from Belitung Island, Indonesia: A comparative study of different solvent extraction methods

This study investigates the medicinal properties of Rhodomyrtus tomentosa by extracting its bioactive compounds with n-hexane, ethyl acetate, and ethanol. Ethyl acetate extract had the highest total phenolic content, while hexane extract had the lowest. The ethanol extract had the highest total flavonoid content, with hexane extract having the lowest. Ethanol extract showed the highest antioxidant activity with an IC50 value of 28.61 ± 0.56 μg/mL. Gas Chromatography-Mass Spectrometry profiling identified major compounds like menthol and salicylic acid. Fraction 6, with rhodomyrtone content of 728 μg/mL, had the most dominant rhodomyrtone compound. Higher solvent polarity correlated with higher total phenolic content, total flavonoid content, and antioxidant activity, but lower saponin content. Based on its contents, further studies are needed to investigate its ability to reduce enteric methane, enhance immunity, and adapt to climate change, both in vitro and in vivo in ruminant livestock.