Evaluation of the Antidiabetic Potential of Rhizophora stylosa Leaf Extract through Enzyme Inhibition and In Vivo Metabolic Modulation

Rhizophora stylosa, a mangrove plant, holds ethnopharmacological promise, but its comprehensive antidiabetic mechanism remains underexplored. This study employed an integrated experimental approach to comprehensively assess the antidiabetic potential of Rhizophora stylosa leaf extract (RSLE), investigating its effects on key enzymes, intestinal glucose handling, and systemic glucose metabolism. Twenty-eight healthy male rats (n=۴ per group) were allocated into seven groups: normal control (CN, vehicle), positive control (PC, acarbose ۴.۵ mg/kg BW), and five treatment groups (T۱-T۵) receiving RSLE at ۵, ۱۰, ۵۰, ۱۰۰, and ۲۰۰ mg/kg BW, respectively. Assessments included in vitro α-amylase and α-glucosidase inhibition assays, an ex vivo everted intestinal sac model for glucose absorption, in vivo oral and intraperitoneal glucose tolerance tests (OGTT/IPGTT), plasma insulin measurement via enzyme-linked immunosorbent assay (ELISA), and histochemical analysis of hepatic and muscle glycogen using PAS staining. RSLE demonstrated in vitro inhibition of α-glucosidase (IC۵۰ = ۱۹۰.۰۸ µg/mL) and α-amylase (IC۵۰ = ۷۶.۶۵ µg/mL). Ex vivo, RSLE (۲۰۰ mg/kg) potently inhibited intestinal glucose absorption. In vivo, RSLE at ۵۰ mg/kg effectively moderated postprandial glucose levels in an OGTT, while the ۲۰۰ mg/kg dose significantly enhanced glucose clearance in an IPGTT. Insulin profiling revealed RSLE modulated secretion, eliciting an acute increase followed by a rapid decline correlating with glucose normalization. Furthermore, RSLE treatment significantly reduced hepatic glycogen storage but did not significantly affect muscle glycogen levels. RSLE exerts antidiabetic effects via an in vitro and in vivo approach, reducing intestinal glucose uptake, enhancing peripheral glucose disposal, and modulating insulin secretion. These findings substantiate its traditional use and highlight its potential as a source of antidiabetic agents.

کلیدواژه ها:

Rhizophora stylosa ، Antidiabetic ، &alpha ، -glucosidase inhibition ، glucose tolerance ، Glycogen ، Insulin Secretion