Diabetes mellitus, particularly type 2 diabetes (T2DM), constitutes one of the foremost global health crises of the twenty-first century, affecting approximately 537 million adults worldwide with projections exceeding 780 million by 2045. Conventional pharmacological interventions carry limitations including adverse side effects, progressive loss of efficacy, and high cost, particularly in low- and middle-income contexts. Plant-derived zinc oxide (ZnO) nanoparticles have emerged as a compelling multifunctional alternative, combining the intrinsic bioactivities of botanical extracts with the quantum-level physicochemical properties of nanoscale ZnO. This review focuses on plant-material applications. It critically examines the green synthesis of ZnO nanoparticles using diverse plant sources, the mechanistic basis of their antihyperglycemic activity encompassing enzymatic inhibition, insulin-mimetic Zn²⁺ ion release, reactive oxygen species (ROS) modulation, and glucose transporter type 4 (GLUT4) translocation and their demonstrated efficacy in vitro and in vivo. Furthermore, it addresses current safety considerations, regulatory frameworks, and the integration of computational biology for predictive antihyperglycemic design. The available preclinical evidence indicates that selected, plant-derived ZnO nanoparticle formulations may inhibit key hyperglycemia-associated enzymes (α-amylase, α-glucosidase) with maximum inhibition efficiencies of up to 96% reported under study-specific assay. In addition, these nanoparticles have been associated with reduced oxidative stress in pancreatic β-cells, and enhanced peripheral glucose uptake. These findings suggest that photosynthesised ZnO nanoparticles represent promising preclinical candidates for further investigation. However, further studies are required to establish their long-term safety, pharmacokinetics, reproducibility, and clinical efficacy.
The essential oil of Rosa damascena Mill. var. trigintipetala Dieck cultivated in Taif, Saudi Arabia was investigated to assess the impact of harvest stage (early, mid, late flowering) and geographical origin (Al-Hada, Al-Shifa, Wadi Mahram) on its chemical composition and physicochemical properties, aiming to establish a scientific basis for national quality standards of Saudi rose oil. GC–MS profiling showed that citronellol declined from 30.5% (early) to 24.6% (late), while geraniol increased from 21.9% to 26.4% and nerol from 10.0% to 13.1%, with the (citronellol + nerol)/geraniol ratio decreasing from 1.72 to 1.51, closer to ISO 9842:2024 specifications. Saturated hydrocarbons rose from 12.4% to 13.9% across harvest stages, whereas unsaturated hydrocarbons declined from 4.3% to 2.7%. Physicochemical analysis confirmed compliance with ISO standards: refractive index (1.463–1.464), optical rotation (−4.39° to −3.25°), relative density (0.856–0.862), ester value (6.85–8.38), and flash point (83–87°C). Geographic differences were evident, with Al-Shifa oils richest in geraniol and nerol and lowest in methyl eugenol, Wadi Mahram oils highest in monoterpene alcohols and lowest in hydrocarbons, and Al-Hada oils distinguished by higher hydrocarbon fractions. Multivariate analyses, including PCA, heatmap visualization, and correlation analysis, further highlighted strong associations among monoterpene alcohols and hydrocarbons, reinforcing harvest stage and origin as critical determinants of oil quality. Late flowering is preferable when a geraniol- and nerol-rich profile is desired, whereas early flowering is advantageous for minimizing methyl eugenol and hydrocarbon content. Overall, Taif rose oils complied with ISO physicochemical requirements but exhibited distinct harvest- and location-dependent profiles. This work provides, to the best of our understanding, the first systematic evaluation of Saudi rose oil standardization and lays the foundation for region-specific quality specifications and national quality-control strategies.
