A simple and rapid spectrofluorimetric method for determining the pharmacokinetics and metabolism of rhaponticin in rat plasma, feces and urine using a cerium probe

A review of alpha-glucosidase inhibitors from plants as potential candidates for the treatment of type-2 diabetes

Diabetes mellitus is a multifactorial global health disorder that is rising at an alarming rate. Cardiovascular diseases, kidney damage and neuropathy are the main cause of high mortality rates among individuals with diabetes. One effective therapeutic approach for controlling hyperglycemia associated with type-2 diabetes is to target alpha-amylase and alpha-glucosidase, enzymes that catalyzes starch hydrolysis in the intestine. At present, approved inhibitors for these enzymes are restricted to acarbose, miglitol and voglibose. Although these inhibitors retard glucose absorption, undesirable gastrointestinal side effects impede their application. Therefore, research efforts continue to seek novel inhibitors with improved efficacy and minimal side effects. Natural products of plant origin have been a valuable source of therapeutic agents with lesser toxicity and side effects. The anti-diabetic potential through alpha-glucosidase inhibition of plant-derived molecules are summarized in this review. Eight molecules (Taxumariene F, Akebonoic acid, Morusin, Rhaponticin, Procyanidin A2, Alaternin, Mulberrofuran K and Psoralidin) were selected as promising drug candidates and their pharmacokinetic properties and toxicity were discussed where available.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11101-021-09773-1.

Rheum rhaponticum Root Extract Improves Vasomotor Menopausal Symptoms and Estrogen-Regulated Targets in Ovariectomized Rat Model

Ovarian insufficiency and ovariectomy are characterized by deregulated heat loss mechanisms. Unlike hormone therapy, ERr 731 (a standardized botanical extract of Siberian rhubarb Rheum rhaponticum L. high in rhaponticin) acts like a selective estrogen receptor modulator for ERβ receptors and may offer a higher degree of safety while maintaining the desired efficacy profile. In this study, we examined the relationship between oral administration of ERr 731 and the underlying components of skin vasomotion responses in an ovariectomized (OVX) rat model. ERr 731 dose-dependently reduced tail skin temperature (T_skin) values by an average of 1 °C. The rapid onset of this effect was observed in 1 and 3 mg/kg/day ERr 731 groups as early as day 2 of administration, and remained in place for the duration of the treatment (2 weeks). Substituting ERr 731 after E₂ withdrawal helped maintain body temperature similarly to E₂ alone, suggesting the usefulness of ERr 731 for replacing existing hormonal therapy in humans. ERr 731 also acted as a highly selective agonist for ERβ in the hypothalamus of OVX rats, as well as in ERα/β cell-based reporter assays. These data validate the OVX/T_skin rat model as a suitable screening platform to evaluate botanical and pharmaceutical treatments of menopause, while providing further evidence for the efficacy of ERr 731 towards alleviating vasomotor menopausal symptoms and improving wellbeing during the menopausal transition.

Validated Microwell-Based Spectrofluorimetric Method for Quantification of Ravidasvir (New Anti-Chronic Hepatitis C Virus-GT4) in Rat Plasma and Its Application to Pharmacokinetic Study

Background

Ravidasvir (RAV) has been regarded as a potent new NS5A inhibitor with a magnificent safety and tolerability in the management of genotype 4 hepatitis C virus (HCV) patients. Suitable analytical techniques are needed for the measurement of RAV in different biological matrices.

Methods

We have developed a fast, sensitive and economical 96-microwell-based spectrofluorimetric technique combined with one-step protein precipitation extraction strategy for the measurement of RAV in rat plasma.

Results

Under the optimum conditions, the direct relationship in rat plasma was accomplished between the RAV concentrations and the fluorescence (FL) intensity in a scope of 2.5–200 ng/mL with 0.9998 and 0.9999 for the quantification and correlation coefficients, respectively. The lower limit of detection (LLOD) was 0.840 ng/mL and this demonstrates the high sensitivity of the proposed assay. The accuracy (RE%) ranged from 95.34% to 102.29%, and the precision (RSD%) was less than 3.59%. The recovery was ranged from 93.12% to 96.26%. The stability of RAV in rat plasma was carried out and established its good stability in the range of room conventional temperature and at long-term stability (−80°C, 30 days). The developed technique was validated as stated by the United States Food and Drug Administration (US-FDA) guidelines for bioanalytical technique verification.

Conclusion

The approved technique was effectively applied for a pharmacokinetic (PK) study after single oral gavage administration of RAV at a dose of 35 mg/kg and it could be presumed that the proposed assay can be applied to clinical trials.