This study is aimed at assessing the antihyperglycemic, antihyperlipidemic, and antioxidant effects ofCitrus reticulata(C. reticulata) fruit peel hydroethanolic extract and two flavonoids, hesperidin and quercetin, in nicotinamide (NA)/streptozotocin- (STZ-) induced type 2 diabetic rats. In addition, GC-MS and HPLC-MS analyses of the extract were performed and the results indicated the presence of multiple flavonoids including hesperidin, quercetin, naringin, and polymethoxylated flavones (nobiletin and tangeretin). To achieve the aim of the study, diabetic rats with NA/STZ-induced T2DM were orally treated withC. reticulatafruit peel hydroethanolic extract, hesperidin, and quercetin at a dose of 100 mg/kg b.w./day for four weeks. The treatments withC. reticulatafruit peel extract, hesperidin, and quercetin significantly ameliorated the impaired oral glucose tolerance; the elevated serum fructosamine level; the diminished serum insulin and C-peptide levels; the altered HOMA-IR, HOMA-IS, and HOMA-βcell function; the decreased liver glycogen content; the increased liver glucose-6-phosphatase and glycogen phosphorylase activities; the deleteriously affected serum lipid profile; the elevated serum AST and ALT activities; and the raised serum creatinine and urea levels in the diabetic rats. The treatments also produced remarkable improvement in the antioxidant defense system manifested by a decrease in the elevated liver lipid peroxidation and an increase in the lowered glutathione content and GPx, GST, and SOD activities. Furthermore, the three treatments enhanced the mRNA expression of GLUT-4 and the insulin receptorβ-subunit, but only quercetin produced a significant increase in the expression of adiponectin in adipose tissue of diabetic rats. In conclusion,C. reticulatafruit peel hydroethanolic extract, hesperidin, and quercetin have potent antidiabetic effects which may be mediated through their insulinotropic effects and insulin-sensitizing actions. In addition, the alleviation of the antioxidant defense system by the extract, hesperidin, and naringin may have an important action to enhance the antidiabetic actions and to improve liver and kidney functions in NA/STZ-induced diabetic rats.

Using a simple approach, silver nanoparticles (Ag NPs) were synthesized from green coffee bean extract. The optical color change from yellowish to reddish-brown of the green-produced Ag NPs was initially observed, which was confirmed by the UV-Visible spectrophotometer’s surface plasmonic resonance (SPR) bands at 329 and 425 nm. The functional groups of green coffee-capped Ag NPs (GC-capped Ag NPs) were studied using a Fourier transform infrared spectrometer, revealing that Ag NPs had been capped by phytochemicals, resulting in excellent stability, and preventing nanoparticle aggregation. The presence of elemental silver is confirmed by energy dispersive X-ray analysis. In addition to the measurement of the zeta potential of the prepared GC-capped Ag NPs, the size distribution is evaluated by the dynamic light scattering. Depending on the nano-morphological study, the particle diameter of Ag NPs is 8.6 ± 3.5 nm, while the particle size of GC-capped Ag NPs is 29.9 ± 4.3 nm, implying the presence of well-dispersed nanospheres with an average capsulation layer of thickness 10.7 nm. The phyto-capped Ag NPs were found to be crystalline, having a face-centered cubic (FCC) lattice structure and Ag crystallite size of ~7.2 nm, according to the XRD crystallographic analysis. The catalytic performance of phyto-capped Ag NPs in the removal of methylene blue dye by sodium borohydride (NaBH₄) was investigated for 12 min to reach a degradation efficiency of approximately 96%. The scavenging activities of 2,2-Diphenyl-1-picrylhydrazyl (DPPH) free radicals are also examined in comparison to previously reported Ag-based nano-catalysts, demonstrating a remarkable IC₅₀ of 26.88 µg/mL, which is the first time it has been recorded.

The present study aimed to evaluate the antihyperglycemic effects of Musa paradisiaca (M. paradisiaca) leaf and fruit peel hydroethanolic extracts and to suggest their probable mode of actions in nicotinamide (NA)/streptozotocin (STZ)‐induced diabetic rats. The leaf and fruit peel hydroethanolic extracts were analyzed by GC‐MS that indicated the presence of phytol, octadecatrienoic acid, hexadecanoic acid, and octadecadienoic acid as major components in the leaf extract and vitamin E, octadecenamide, β‐sitosterol, and stigmasterol as major phytochemicals in the fruit peel extract. Diabetes mellitus was induced by a single intraperitoneal injection of STZ (60 mg/kg body weight) dissolved in citrate buffer (pH 4.5), 15 minutes after intraperitoneal injection of NA (120 mg/kg body weight). The NA/STZ‐induced diabetic rats were, respectively, treated with M. paradisiaca leaf and fruit peel hydroethanolic extracts at a dose of 100 mg/kg body weight/day by oral administration for 28 days. The treatment of NA/STZ‐induced diabetic rats with leaf and fruit peel extracts significantly improved the impaired oral glucose tolerance and significantly increased the lowered serum insulin and C‐peptide levels. The HOMA‐IR (as the index of insulin resistance) and QUICKI (as a marker for insulin sensitivity), as well as HOMA‐β cell function were significantly alleviated as a result of treatment of diabetic rats with leaf and fruit peel extracts. In association, the elevated serum‐free fatty acids, TNF‐α, and IL‐6 levels were significantly decreased. In addition, the suppressed adipose tissue PPARγ, GLUT4, adiponectin, and insulin receptor β‐subunit mRNA expressions were upregulated while the elevated adipose tissue resistin expression was downregulated in diabetic rats as a result of treatment with the leaf and peel extract. Based on these results, it can be concluded that M. paradisiaca leaf and fruit peel hydroethanolic extracts have antihyperglycemic effects which may be mediated via their insulinotropic and insulin‐sensitizing effects.