Evaluation of Antioxidant Potential in Extracts from Underutilized Sri Lankan Fruits and Leaves.

Abstract

Background: Exploring natural antioxidants derived from underutilized sources holds substantial potential for improving human health and nutrition by mitigating oxidative stress and associated diseases. Objective: To evaluate the antioxidant capacity of extracts derived from underutilized fruits and leaves, specifically Lovi (Flacourtia inermis), Veralu (Elaeocarpus serratus), Polos (Artocarpus heterophyllus), Bilin (Averrhoa bilimbi), Siyambala (Tamarindus indica), and Ambarella (Spondias dulcis) sourced from Sri Lanka Methods: The fruits and leaves underwent extraction processes using water and methanol. For the hot water extraction, 10 grams of dried and powdered sample were used. For the maceration process, 5 grams of dried and powdered samples were soaked in a mixture of water and methanol. This involved preparing a hot water extract, a room temperature macerated water extract, and a methanol extract. Subsequently, these extracts were assessed for their antioxidant activity using in-vitro bioassays, namely the DPPH assay (2,2-diphenyl-1-picrylhydrazyl) and the ABTS assay (2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid). Results: Among fruit extracts, Veralu and Lovi hot water extracts showed the highest scavenging activity as 90.46% and 90.53% respectively at 1 mg/mL. Among the leaf extracts, Veralu leaf hot water extract and macerated water extract displayed the highest scavenging activity with values 90.74% and 90.53%, respectively at 1 mg/mL, suggesting their potential as valuable sources of antioxidants by the ABTS assay. All three fruit and leaf extracts of Veralu depicted high scavenging activity values by the DPPH assay. Among fruit extracts, Veralu hot water extract displayed scavenging activity as 86.3% and for the macerated water extract as 80.55% at 1 mg/mL. Among the leaf extracts, Veralu leaf hot water extract and macerated methanol extract displayed scavenging activity as 86.30% and 77.90%, respectively at 1 mg/mL. Ascorbic acid was used as the positive control where 88.42% was found for ABTS and 61.10% was found for DPPH as radical scavenging values. Conclusion: Among the six fruits studied, Veralu fruit and leaf extracts exhibited high antioxidant activity in both the DPPH and ABTS assays, indicating their potential as rich sources of antioxidants.