Diabetes has always been a matter of concern to health experts as well as the community due to the increasing number of patients with diabetes and the severe consequences it may cause. Many attempts have been made to discover new treatment options for diabetes, and herbal medicines are currently considered to have great potential. This study was conducted to evaluate the effect ofCamellia flavaflower extract on the degeneration of the islets of Langerhans and insulin resistance in an alloxan-induced hyperglycemia model in Swiss albino mice. Hyperglycemic conditions were induced by alloxan (55 mg/kg, i.v.). The animals were then treated with glibenclamide (10 mg/kg, p.o.) and flower extract at doses of 1.09 and 2.19 g/kg, p.o. The results showed that the blood glucose, AUC, HbA1c, and HOMA-IR levels of two groups of mice receiving flower extract were considerably lower than those of the hyperglycemic untreated group (p < 0.05). The body weights of these two groups were also lower than the untreated group on the last day of the experiment, though the differences were not significant (p > 0.05). However, this was not observed when assessing insulin levels as well as relative organ weights. In biochemical tests, creatinine and AST and ALT concentrations were evaluated. There was no significant variation in creatinine and AST concentrations between the five experimental groups, whereas mice treated with glibenclamide and flower extract at both doses showed a remarkable decline in ALT concentration (p < 0.05). The hepatic histomicrographs were consistent with ALT results, while the H&E staining of kidneys showed no difference between groups. Histomicrographs of the pancreas revealed that the treatment groups using glibenclamide and flower extract had larger islets of Langerhans than those of the alloxan-treated group. Based on these results, this study demonstrated thatCamellia flavaflower extract exerted several beneficial effects, including blood sugar level reduction, weight loss promotion, and organ protection, hence making it a new potential herbal medication for the management of diabetes.

Mangiferin is a xanthonoid found in Mango leaves in abundance with many effects as a hypoglycemic, antioxidant, and anti-inflammatory agent, plant metabolite, and so on. However, nowadays, mango leaves are merely a waste product in Vietnam. To take advantage of this valuable medicinal resource, extraction conditions of mangiferin using classical and ultrasound methods were researched, and mangiferin was purified from Cat Chu mango leaves (Mangifera indica L., Anacardiaceae) collected in Dong Thap. Ultrasound-assisted extraction method was conducted with the following conditions and mangiferin was extracted at a percentage of 6.728% with a purity of 91.11%. Purified mangiferin was evaluated using molecular absorption spectroscopy UV-Vis, scanning electron microscopy (SEM), X-ray diffraction (XRD) spectroscopy, simultaneous thermal analysis (STA: TGA/DSC), and dissolution measurement method. To optimize the solubility and permeability of mangiferin, the solid dispersion system (HPTR) was made by the combination of HPMC 6M:mangiferin at the ratio of 1:5. To investigate the acute, sub-chronic toxicity and hypolipidemia effect of HPTR as compared to purified mangiferin, we followed guidelines for preclinical and clinical trials of Traditional Medicine and Herbal Medicines by the Vietnam Ministry of Health and OECD, and used tyloxapol (Triton WR1339, 400 mg/kg, i.p.) to induce hyperlipidemia. Our results indicated that purified mangiferin and HPTR extract showed no acute toxicity and sub-chronic toxicity and has potential as an antihyperlipidemic agent. The HPTR brought about a significant decrease in total cholesterol, triglycerides and LDL-c when compared to mangiferin, however there was no significance between them.

Vitexin and isovitexin are natural flavone C-glucosides that have numerous benefits for human health. However, their low oral bioavailability and poor gastrointestinal absorption dramatically restrict their potential medicinal uses. To overcome this challenge, chitosan-coated alginate microcapsules were prepared for intragastrical administration to rabbits. An LC-MS/MS method was developed and validated for the simultaneous determination of vitexin and isovitexin in the plasma of treated rabbits, using salicylic acid as the internal standard. Raw rabbit plasma samples were deproteinized using acetonitrile as a precipitation agent. Chromatographic separation was performed on a reversed-phase C18 column (100 mm × 4.6 mm, 3.5 µm), with an isocratic mobile solvent system comprising methanol and 0.1% acetic acid (40:60) as the mobile phase. All the analytes and the internal standard were ionized on a triple quadrupole mass spectrometer and electrospray ionization, operating in negative mode and multiple reaction monitoring. The analytical approach developed underwent validation in terms of system suitability, specificity, selectivity, LLOQ of 2 ng/mL, linearity (2.0–200 ng/mL, R² > 0.99), accuracy (the intra- and inter-day from 94 to 110% with the relative standard deviations no more than 8.7%, precision with the recoveries from 97% to 102%, matrix effect (90–100%), carry-over, dilution integrity (2 times), and stability at room and frozen temperature for up to 1 month, and all the parameters met FDA and EMA requirements for bioanalytical methods. The validated procedure was applied to measure the absorption of vitexin and isovitexin from encapsulated extracts in a pilot pharmacokinetic study on rabbit plasma. Compared to the raw traditional extracts, the microcapsules enhanced the bioavailability of vi-texin and isovitexin regarding C_max and AUC values.