Effect of infusions based on fig leaves (Ficus carica) and stevia (Stevia rebaudiana) on antioxidant capacity and inhibition of the α-glucosidase enzyme in vitro

Ficus carica and Stevia rebaudiana leaves exhibited biological activity, specifically antioxidant activity and α-glucosidase enzyme inhibition. This research aimed to evaluate the antioxidant activity through the DPPH and ABTS methods, as well as the in vitro α-glucosidase enzyme inhibition of fresh and dried leaf infusions at different concentrations. Results showed that infusions made with dried leaves demonstrated higher biological activity than those made with fresh leaves. When evaluated separately, the leaves showed low antioxidant activity percentages in the DPPH and ABTS tests. For fresh leaves, Ficus carica presented (41.1% ± 1.9), and Stevia rebaudiana (46.1% ± 1.1), while for dried leaves, Ficus showed (75% ± 1.8) and Stevia (87% ± 2.1). In enzyme inhibition, Ficus carica showed (7.9% ± 1.2), and Stevia (37.9% ± 1.3). When the dried leaves were combined, antioxidant capacity and α-glucosidase enzyme inhibition increased. In the DPPH neutralization test, the best results were achieved with an infusion containing a 2.5:1.5 ratio of Ficus carica and Stevia rebaudiana, showing 59% neutralization. In the ABTS radical neutralization test, the infusion with a 1:1 ratio of fresh leaves achieved a reduction of (88.5%). Lastly, in the α-glucosidase enzyme inhibition test, the highest percentage was obtained with the 2:1 infusion of Ficus carica and Stevia rebaudiana, achieving (67%), and with the 1:1 treatment of both fresh leaves, achieving (62.1%). This demonstrates that the combination of these leaves exhibits a synergistic effect, enhancing the biological activity of these plants.