Abstract:
Kuntorini EM, Triyasmono L, Astuti MD. 2024. Antioxidant activity and 1H NMR profiling of leaves and fruits of Rhodomyrtus
tomentosa from South Kalimantan, Indonesia. Biodiversitas 25: 2020-2027. Rhodomyrtus tomentosa (Aiton) Hassk is a flowering plant
belonging to Myrtaceae, native to southern and southeastern Asia. This study aims to evaluate and compare the antioxidant activity of
leaves and fruits ethanol extracts of R. tomentosa (Ait.) Hassk from two locations, namely Banjar and Batola, South Kalimantan
Province, Indonesia. The samples included old and young leaves and three stages of fruit maturity, namely green, red, and purple. 1H
NMR spectroscopy was used to identify the chemical profile of extracts, which comprised organic acids, carbohydrates, amino acids,
and phenolic compounds. Antioxidant capacity was assessed with DPPH, which showed intensity differences in aromatic shifts in leaves
and fruits for both regions. Young leaves and green fruits had higher intensity than old leaves and red and purple fruits, correlating with
antioxidant capacity. Analysis of 1H NMR spectra of young and old leaf extracts identified vital metabolites, such as gallic acid,
myricetin 3-O-rhamnopyranoside, myricetin, quercetin, quercetin-3-O-glucoside, as well as syringic acid, in regional chemical shifts of
10.0-6.0 ppm as aromatic compound area. The differences in spectral signal intensity revealed higher metabolite levels, specifically
carbohydrates and amino acids, in red and purple fruits. However, green fruits had higher quantities of aromatic compounds.
