Asian Journal of Research in Biochemistry

Background and Aims: Cotton (Gossypium hirsutum L.), a plant in the Malvaceae family, contains a number of secondary metabolites with antioxidant qualities, such as flavonoids, tannins, saponins, and steroids. This study aims to determine the total phenolic content and antioxidant activity of the ethanolic extract of cotton fruit peel (Gossypium hirsutum L.) using a UV–Vis spectrophotometric method.

Study Design: An experimental laboratory study involving maceration extraction, quantitative phenolic analysis, and antioxidant activity evaluation using the DPPH assay.

Place and Duration of Study: Department of Pharmacy, Faculty of Pharmacy, Universitas Perintis Indonesia, Padang, West Sumatera, Indonesia January-June 2025.

Methodology: Maceration was used for extraction, with 70% and 96% ethanol serving as solvents. The Folin–Ciocalteu technique was used to quantify the total phenolic content, and a UV–Vis spectrophotometer was used to measure absorbance at the maximum wavelength of 765 nm. The DPPH radical scavenging method was used to assess antioxidant activity, and absorbance at 520 nm was determined.

Results: The total phenolic content of the ethanolic extract of cotton fruit peel was found to be 9.699% w/w ± 0.0509. Antioxidant activity testing showed an IC₅₀ value of 10.40 µg/mL, corresponding to a gallic acid equivalent (GAE) value of 3.502.

Conclusion: The ethanolic extract of cotton fruit peel exhibits very strong antioxidant activity, as indicated by an IC₅₀ value of less than 50 µg/mL.