Determination of Total Tannin Content and Antioxidant Activity of the Ethanol Extract from Senduduk Leaves (Melastoma malabathricum L.)

Abstract

Background: Antioxidants are molecules capable of donating one or more electrons to free radicals, thereby stabilizing and neutralizing them. By doing so, antioxidants help protect the body from oxidative stress and its associated health risks. Aims: This study aims to determine the total tannin content and antioxidant activity of Senduduk leaves using a UV‑Vis spectrophotometer method. Study Design: Experimental laboratory study involving maceration extraction, qualitative and quantitative phytochemical analysis, and DPPH antioxidant assay. Place and Duration of Study: Department of Pharmacy, Faculty of Pharmacy, Universitas Perintis Indonesia, Padang, West Sumatera, Indonesia January-June 2023. Methodology: Extraction was performed by maceration with 70% ethanol solvent. Tannins in the ethanol extract of Senduduk leaves were identified qualitatively (bluish‑black color and precipitate formation with 5% FeCl₃ and gelatin) and quantified by measuring absorbance at 764 nm using a UV‑Vis spectrophotometer. Antioxidant activity was determined via the DPPH method, measuring absorbance at 519 nm. Results: Qualitative analysis confirmed presence of tannins. The maximum absorption wavelength of tannic acid was found at 764 nm. Total tannin content was 32.71% w/w ± 0.06. Validation parameters for tannin determination were BD = 1.63 ppm, BK = 5.44 ppm, and CV = 0.18%. For antioxidant activity, the IC₅₀ value of the ethanol extract was 24.00 ppm, with a GAE value of 10.61 mg. The antioxidant activity of the ethanolic extract of Senduduk leaves was assessed using the DPPH radical scavenging method, a widely accepted and simple assay to evaluate free radical inhibition potential. The extract exhibited an IC₅₀ value of 24.00 µg/mL, which classifies it as having moderate antioxidant activity. Conclusion: Senduduk leaves possess very strong antioxidant activity. The findings suggest that the tannin-rich extract contributes significantly to the antioxidant potential of Senduduk leaves, indicating its potential use as a natural antioxidant in nutraceutical or pharmaceutical formulations. Future studies should focus on the isolation, fractionation, and mechanistic evaluation of specific active compounds to further explore their therapeutic potential.