Antidiabetic and antioxidant potentials of selected traditional Palestinian medicinal plants

Introduction: Diabetes mellitus is a major and increasing public health burden in Palestine. Medicinal plants are widely employed in traditional practice, yet their antidiabetic efficacy and mechanisms remain insufficiently validated. This study aimed to evaluate the antidiabetic and antioxidant potential of Palestinian medicinal plants by assessing α-amylase and α-glucosidase inhibitory activities, antioxidant capacity, and flavonoid content. Materials and methods: A total of 108 ethanolic extracts from 98 plant taxa were evaluated for inhibitory activity against α-amylase and α-glucosidase. Extracts showing > 50% enzymatic inhibition underwent IC50 determination. Antioxidant activity was assessed using ABTS (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)) and Trolox-equivalent assays. Enzymatic inhibition patterns were classified using median-based thresholds, and statistical analyses explored relationships among variables. Results: Sixty-four percent of extracts inhibited α-glucosidase and 55% inhibited α-amylase. Several extracts demonstrated potent α-glucosidase inhibition (IC50 < 1 mg/mL), in some cases surpassing the reference drug. Promising species included Rhus coriaria, Ceratonia siliqua, Cinnamomum zeylanicum, Psidium guajava, Camellia sinensis, Quercus coccifera, and Cistus creticus. Dual inhibitory activity was observed in multiple extracts, particularly among plants traditionally used for diabetes management. Antioxidant activity was notable, with 65% of extracts showing significant antioxidant activity. Statistical analyses revealed moderate association between antioxidant activity and enzyme inhibition, while flavonoid content showed no direct correlation. Conclusions: Palestinian medicinal plants constitute a valuable source of bioactive compounds with significant α-glucosidase and moderate α-amylase inhibitory activities. These findings provide scientific validation for their ethnopharmacological relevance and highlight several species as promising candidates for phytotherapeutic development or functional food for diabetes management.