A fluorescence strategy for monitoring α-glucosidase activity and screening its inhibitors from Chinese herbal medicines based on Cu nanoclusters with aggregation-induced emission

<i>Tinospora cordifolia</i> - A Future Green Material for Copper Oxide Nanoparticle-based Drug, Reduces the Risk of Diabetes and Cancer

Background: Copper nanoparticles (CuONPs) have garnered significant attention for their unique properties and potential applications in agriculture, medicine, and environmental science. Using eco-friendly methods, the stem extract of Tinospora cordifolia, a medicinal plant known for its bioactive compounds, can act as a reducing agent for CuONP synthesis. This approach minimises environmental impact while leveraging the plant’s inherent medicinal properties. Aim: To synthesise and characterise CuONPs using T. cordifolia stem extract and evaluate their agricultural, anti-diabetic, and anticancer applications. Methods: Copper nanoparticles were synthesised using T. cordifolia stem extract. UV-visible spectroscopy identified the characteristic plasmon resonance peak at 300 nm, while X-Ray Diffraction (XRD) confirmed the crystalline structure of CuONPs. Fourier Transmission Infrared Spectroscopy (FTIR) indicated the stabilization of CuONPs by biomolecules. Scanning Electron Microscopy (SEM) and energy dispersive X-ray (EDX) revealed an approximate size of 100 nm in one dimension. Applications included hydroponic lettuce growth enhancement, anti-diabetic activity (via α-glucosidase inhibition), and anticancer efficacy (via MTT assay on MCF-7 cell lines). Results: The CuONPs improved lettuce growth under hydroponics by enhancing moisture content, leaf length, and plant weight at a concentration of 25 mg/L. In biomedical studies, CuONPs exhibited significant anti-diabetic activity with an IC50 value of 95.42 μg/mL and potent anticancer activity with an IC50 value of 35.51 μg/mL against MCF-7 cells. Conclusion: Biogenic CuONPs synthesised using T. cordifolia demonstrate promising multifunctional applications. Their eco-friendly synthesis, agricultural benefits, and biomedical efficacy suggest they are a sustainable and versatile nanomaterial for future use. Major Findings: CuONPs synthesized using Tinospora cordifolia stem extract enhanced hydroponic lettuce growth, exhibited anti-diabetic activity (IC50: 95.42 μg/mL), and demonstrated potent anticancer effects (IC50: 35.51 μg/mL) against MCF-7 cells, highlighting their multifunctional potential.

Fluorescent metal nanoclusters: From luminescence mechanism to applications in enzyme activity assays

Metal nanoclusters (MNCs) have outstanding fluorescence property and biocompatibility, which show widespread applications in biological analysis. Particularly, evaluation of enzyme activity with the fluorescent MNCs has been developed rapidly within the past several years. In this review, we first introduced the fluorescent mechanism of mono- and bi-metallic nanoclusters, respectively, whose interesting luminescence properties are mainly resulted from electron transfer between the lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) energy levels. Meanwhile, the charge migration within the structure occurs through ligand-metal charge transfer (LMCT) or ligand-metal-metal charge transfer (LMMCT). On such foundation, diverse enzyme activities were rigorously evaluated, including three transferases and nine hydrolases, in turn harvesting rapid research progresses within past 5 years. Finally, we summarized the design strategies for evaluating enzyme activity with the MNCs, presented the major issues and challenges remained in the relevant research, coupled by showing some improvement measures. This review will attract researchers dedicated to the studies of the MNCs and provide some constructive insights for their further applications in enzyme analysis.

Critical Assessment of In Vitro Screening of α-Glucosidase Inhibitors from Plants with Acarbose as a Reference Standard

Postprandial hyperglycemia is treated with the oral antidiabetic drug acarbose, an intestinal α-glucosidase inhibitor. Side effects of acarbose motivated a growing number of screening studies to identify novel α-glucosidase inhibitors derived from plant extracts and other natural sources. As "gold standard", acarbose is frequently included as the reference standard to assess the potency of these candidate α-glucosidase inhibitors, with many outperforming acarbose by several orders of magnitude. The results are subsequently used to identify suitable compounds/products with strong potential for in vivo efficacy. However, most α-glucosidase inhibitor screening studies use enzyme preparations obtained from nonmammalian sources (typically Saccharomyces cerevisiae), despite strong evidence that inhibition data obtained using nonmammalian α-glucosidase may hold limited value in terms of identifying α-glucosidase inhibitors with actual in vivo hypoglycemic potential. The aim was to critically discuss the screening of novel α-glucosidase inhibitors from plant sources, emphasizing inconsistencies and pitfalls, specifically where acarbose was included as the reference standard. An assessment of the available literature emphasized the cruciality of stating the biological source of α-glucosidase in such screening studies to allow for unambiguous and rational interpretation of the data. The review also highlights the lack of a universally adopted screening assay for novel α-glucosidase inhibitors and the commercial availability of a standardized preparation of mammalian α-glucosidase.