Plant-Based Potential in Diabetes Management: In Vitro Antioxidant, Wound-Healing, and Enzyme Inhibitory Activities of Southern Algarve Species

Abstract

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by impaired glucose regulation. This study evaluated the antioxidant and antidiabetic potential of aqueous extracts from four plant species from the southern Algarve: Aristolochia baetica, Chelidonium majus, Dittrichia viscosa, and Lavandula viridis, using non-cellular in vitro assays. HPLC/PDA was used to identify active compounds. Antioxidant activity was assessed by using TAA, FRAP, RP, and DPPH assays; antidiabetic potential through α-glucosidase and α-amylase inhibition; and wound healing relevance through elastase, collagenase, and lipoxygenase inhibition. D. viscosa showed the highest antioxidant activity (FRAP: 1132.99 ± 19.54 mg TE/g dw; DPPH IC50 = 25.85 ± 0.75 μg/mL) and total phenolic/flavonoid content, with a diverse profile including caffeic and chlorogenic acids, isoquercetin, and quercetin. It also exhibited potent α-glucosidase inhibition (IC50 = 0.61 ± 0.06 mg/mL), outperforming acarbose. L. viridis had the highest total phenolic content (39.04 mg/g), while A. baetica demonstrated the strongest anti-elastase, anti-collagenase, and lipoxygenase activity, suggesting wound-healing potential. C. majus showed the weakest effects. A strong correlation was observed between phenolic content and antioxidant/antidiabetic activity. These findings support further in vivo studies on D. viscosa and A. baetica for potential use in T2DM management and diabetic wound healing.