Diabetes mellitus remains a major global health burden, and many patients do not achieve durable glycemic control despite modern pharmacotherapy. This narrative review synthesizes evidence on plant-derived strategies that may complement standard care, focusing on two clinically aligned domains: glucose-lowering medicinal plants and plant-based sugar substitutes that reduce dietary glycemic load. We summarize key mechanistic pathways, including inhibition of α-amylase/α-glucosidase, reduced intestinal glucose entry and absorption kinetics, glucose-dependent insulinotropic effects, improved insulin signaling, suppression of hepatic gluconeogenesis, and microbiota-linked effects. We critically appraise human evidence for selected botanicals (cinnamon, fenugreek, mulberry, gymnema, gynura, rosehip, and Jerusalem artichoke) and plant sweeteners (stevia and monk fruit). Overall, clinical effects are modest and heterogeneous; the most reproducible signals are observed for mulberry leaf in blunting postprandial glucose excursions, and for cinnamon, fenugreek, and gymnema, where meta-analyses suggest modest improvements in glycemic markers. Stevia and monk fruit are best supported as glycemically neutral sucrose substitutes, while inulin-type fructans show small-to-moderate benefits with sustained intake, limited by gastrointestinal tolerability at higher doses. Key gaps include a shortage of long-term randomized trials using standardized preparations and durable endpoints such as glycated hemoglobin. Plant-derived interventions are therefore best positioned as adjuncts within individualized, evidence-based glycemic management.

The aim of the study was to develop the system of polymerase chain reaction (PCR)-based markers for the assessment of genetic diversity and population genetic studies of Gentiana lutea L. as well as to determine the utility of two indices of marker informativeness. The informativeness was determined for 40 PCR primers of different types (random amplified polymorphic DNA, inter simple sequence repeat, inter-retrotransposon amplified polymorphism, resistance gene analog polymorphism and conserved DNA-derived polymorphism markers) by evaluating discriminating power (D_L) and resolving power (R_p) in a sample of 30 plants from two populations. Analysis of correlation between the index value and the number of differentiated pairs of genotypes in the given sample revealed that D_L is more efficient than R_p; therefore, we selected primers based on the D_L value. In total, 12 primers with the largest values of D_L were chosen. Analysis of genetic relationship among 86 plants from six populations showed that the number of bands produced by the three of selected primers was sufficient to give average bootstrap support across six key nodes in the dendrogram higher than 85%, while using six of the primers resulted in average bootstrap value exceeding 99%. Thus, a minimal set of three to six selected primers are sufficient for a quick assessment of genetic diversity of G. lutea populations, depending on the sample size and degree of differentiation between populations, while the rest of the primers with D_L values above 0.8 may be used for ecogenetic surveys. Preliminary results obtained with selected primers indicate the moderate level of genetic variation within the species and significant differentiation among individual populations.