Antidiabetic Properties of Ficus deltoidea Jack: A Review of In Vitro, In Vivo, and Clinical Evidence

Ficus deltoidea Jack (Moraceae), locally known as Mas Cotek, is a medicinal plant traditionally used throughout Southeast Asia for the management of diabetes mellitus. This review summarises the available evidence on the antidiabetic properties of F. deltoidea based on eleven in vitro, nine in vivo and one clinical study identified through a structured literature search. In vitro investigations show that F. deltoidea inhibits α-glucosidase and α-amylase, stimulates insulin secretion in pancreatic β-cells via both K+-ATP channel-dependent and -independent pathways, enhances glucose uptake in hepatocytes and adipocytes, promotes adiponectin secretion and inhibits protein tyrosine phosphatase 1B (PTP1B). Vitexin and isovitexin, the predominant C-glycosyl flavonoids in F. deltoidea leaves, appear to be the main bioactive compounds responsible for these effects. Meanwhile, in vivo studies in streptozotocin-induced diabetic rodents report dose-dependent reductions in fasting blood glucose, improved glucose tolerance, restoration of pancreatic islet architecture, modulation of hepatic gluconeogenic and glucose-metabolic genes, and protection against diabetic nephropathy and bone loss. Inter-varietal differences in chemical composition and biological activity were observed, with var. trengganuensis and var. intermedia reported as the most active. The only available clinical trial in adults with prediabetes (1000 mg/day for 8 weeks) showed a reduction in LDL and total cholesterol but no significant change in fasting blood glucose or insulin. The discrepancy between preclinical and clinical findings highlights the need for standardised extracts, pharmacokinetic studies and adequately powered clinical trials in patients with established type 2 diabetes mellitus.