Antidiabetic Medicinal Plants of Uzbekistan and Central Asia: Ethnopharmacology and Mechanisms of Action – A Narrative Review

Abstract

Type 2 diabetes mellitus (T2DM) continues to rise sharply across Central Asia, driven by rapid urbanisation, dietary transition, and an ageing population, and places a growing burden on national health systems in the region, including Uzbekistan, where the number of adults living with diabetes is estimated to have grown from roughly 813,000 in 2011 to approximately 1.5 million in 2024, with nearly three-quarters of cases believed to remain undiagnosed. Traditional Central Asian medicine has for centuries employed a range of locally available plants to manage “sugar disease”, yet only a fraction of this ethnopharmacological knowledge has been subjected to rigorous mechanistic and clinical evaluation. This narrative review synthesises recent (2008–2024) evidence on five medicinal plant taxa native to or widely used in Uzbekistan and the broader Central Asian region – Berberis vulgaris (barberry), Trigonella foenum-graecum (fenugreek), Juglans regia (walnut), Urtica dioica (stinging nettle), and Glycyrrhiza glabra (licorice) – with respect to their antidiabetic activity and underlying mechanisms. We discuss berberine, the principal isoquinoline alkaloid of Berberis species, which activates AMP-activated protein kinase, enhances insulin receptor and GLUT4 expression, suppresses hepatic gluconeogenesis, and favourably modulates gut microbiota composition; fenugreek seed constituents (4-hydroxyisoleucine, trigonelline, and furostanolic saponins), which have demonstrated clinically meaningful reductions in fasting and postprandial glycaemia in randomised trials; walnut leaf polyphenols, for which mechanistic and single-arm clinical data suggest a hypoglycaemic effect but a recent double-blind placebo-controlled trial found no significant effect on glycaemic indices, illustrating the importance of distinguishing preclinical promise from confirmed clinical benefit; stinging nettle leaf extracts, which inhibit intestinal disaccharidases and glucose transport in vitro; and licorice root constituents, particularly glabridin and glycyrrhetinic acid, which enhance cellular glucose uptake and inhibit intestinal α-amylase activity. We additionally compare the five plants by principal bioactive constituent, proposed mechanism, and strength of clinical evidence, and discuss safety and herb-drug interaction considerations relevant to their concomitant use with conventional antidiabetic therapy. We conclude that Central Asian medicinal flora offers several mechanistically plausible and, in the case of fenugreek and berberine, clinically supported adjuncts to standard antidiabetic therapy, but that rigorous, adequately powered clinical trials using standardised regional plant material remain the principal unmet need before any of these plants can be recommended as evidence-based adjuncts to pharmacotherapy.