Effect of Geographical Locations on the Antioxidant Activity of Melastoma malabathricum L. Leaves Extracts from Riau and Riau Island Provinces, Indonesia

Melastoma malabathricum L. is renowned for its composition of diverse bioactive substances, including polyphenols, tannins, alkaloids, and terpenoids. Several studies have shown that the plant is widely distributed across several tropical regions, particularly Indonesia. Therefore, this study aims to examine the effect of geographical location on the antioxidant activity of M. malabathricum leaf (young and old) extracts in Riau and Riau Island provinces. The sampling locations comprised 3 areas in Riau,rIsland province, namely 1. Bintan (BI), 2. Tanjung Pinang (TP), and 3. Karimun (KR), as well as 3 areas in Riau province, including 4. Kampar (KM), 5. Kuantan Singingi (KS), and 6. Meranti (MR). M. malabathricum leaf extracts were obtained with ultrasonic extraction using methanol, while the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging method was used to measure their antioxidant activity. The results showed that the young leaf extract hanx,cd higher antioxidant activity compared to the older leaf extract. The Bintan (BI) region from Riau Island province had the highest percentage inhibition of 92.0038 ± 0.6757, followed by Tanjungpinang (TP), Karimun (KR), Kampar (KM), Kuantan Singingi (KS), and Meranti (MR) with 87.9961 ± 6.7443, 78.5433 ± 2.5160, 77.4373 ± 3.1645, 71.8304 ± 25.3014, 56.9942 ± 31.8121, respectively. The leaves from Riau Island province contained more phytochemical compounds compared to Riau province, leading to their commercial production as a natural tea with antioxidant agents. To enhance the results of this study, further phytochemical analysis of the antioxidant potential of the extracts is recommended for improving their health benefits.