A putative SGLT-relevant mechanistic perspective on quercetin-3-O-glucoside and rutin in diabetic kidney disease

Type 2 diabetes mellitus (T2DM) is escalating worldwide and remains difficult to control durably, in part because progressive β-cell dysfunction undermines many therapies and because long-term management must balance efficacy, safety, and affordability. Recent decades have shown that targeting sodium-glucose cotransporters (SGLTs) especially renal SGLT2 can reduce glucose levels independently of insulin and, crucially, deliver cardio-renal benefits that extend beyond glycaemic control. Yet, despite the clinical success of synthetic "gliflozins", gaps remain, adverse events, incomplete inhibition of renal glucose reabsorption, and limited access in some health systems.

This review focuses on two quercetin glycosides quercetin-3-O-glucoside (isoquercitrin) and quercetin-3-O-rutinoside (rutin) as potential SGLT-focused modulators. This study employed a narrative mechanistic review approach integrating published experimental evidence, physicochemical structure-activity relationship (SAR) analysis, and exploratory molecular docking to examine potential SGLT-related interactions and complementary glucose-regulatory pathways of Q3G and rutin.

We synthesise mechanistic evidence suggesting that Q3G and rutin may modulate SGLT-related pathways through intestinal SGLT1 interaction, regulation of renal SGLT2 expression, and complementary glucose-regulatory mechanisms. However, direct inhibition of human SGLT2 transport activity has not yet been experimentally demonstrated, and current evidence predominantly may indicate indirect pathway modulation rather than gliflozin-like transporter inhibition. Contradictory findings across assay systems are discussed in relation to structure-activity relationships shaped by glycosylation. We further examine pharmacokinetics, tissue exposure plausibility, and translational feasibility, and propose a stepwise development roadmap emphasising transporter-specific assays, quantitative target engagement, and clinically meaningful biomarkers.

Q3G and rutin may exhibit putative SGLT-relevant activity within a broader polypharmacological framework; however, direct transporter-specific inhibition and clinically relevant renal exposure remain to be established through future functional and translational studies.