Antioxidant and Antibacterial Activities of Aqueous and Hydroethanolic Extracts from the Pericarp of Garcinia mangostana L.

Abstract

Background: Oxidative stress and antibiotic-resistant bacterial infections pose major global health challenges, increasing interest in plant-based alternatives. Garcinia mangostana is traditionally used for its bioactive compounds with potential antioxidant and antibacterial properties. Aim: To carry out a phytochemical screening and to evaluate the antioxidant and antibacterial activity of aqueous and hydroethanol extracts from the pericarp of the fruit of Garcinia mangostana (Clusiaceae). Methodology: Hydroethanolic Extracts from the Pericarp of Garcinia mangostana L were prepared and phytochemical screening was carried out using colorimetric tests for qualitative analysis and spectrometric assays for quantitative analysis. Antioxidant activity was assessed by FRAP and DPPH methods. Antibacterial activity was determined using the Broth Microdilution technique on 4 bacterial strains including Enterobacter cloacae, S. aureus, Escherichia coli, Pseudomonas aeruginosa. The bacteria sought came from samples analyzed at the Microbiology Laboratory of the University Clinics of the Mountains, purified on nutrient agar. Results: Extraction yields varied from 1% to 2.76%. The highest yield was obtained by hydroethanol maceration (2.76%), while the lowest was obtained by aqueous maceration (1%). Phytochemical screening revealed the presence of alkaloids, flavonoids, saponins, phenols, tannins and anthocyanins, with a higher concentration of total phenols in each extract. In addition, the hydroethanol extract showed the best anti-free radical activity particularly when measured using the DPPH method, where the IC50 of 15.71 µg/mL was lower than that obtained with butylhydroxy toluene extract (IC50 of 17.91 µg/mL). Although the opposite result were obtained using the FRAP method (IC50 of 18.97 and 15.82 µg/mL respectively), the IC50 value remained below 20 µg/mL indicating strong antioxidant activity of hydroethanol extract. In parallel, the same hydroethanol extract showed strong inhibition of Enterobacter cloacae (0.16µg/ml), S. aureus (0.32µg/ml) and Escherichia coli (0.64µg/ml), while Pseudomonas aeruginosa was inhibited with a lower concentration 0.24µg/ml of aqueous decoction than the other extracts. Conclusion: Hydroethanolic extracts of Garcinia mangostana pericarp possess antioxidant and antibacterial properties, justifying their use in traditional medicine.