Asian Pacific Journal of Tropical Biomedicine

9-19

Authors: Kolawole A Olofinsan, Ochuko L Erukainure, Beseni K Brian, Md. Shahidul Islam

Objective: To investigate the antioxidative and antidiabetic effects of Harpephyllum caffrum bark infusion as well as its effects on glucogenic and nucleotide hydrolyzing enzyme activities in FeSO4- induced oxidative stress in rat hepatic tissue. Methods: Harpephyllum caffrum infusion was prepared from dried plant materials (40 g) infused in boiling water (400 mL) for 20 min at room temperature. The antioxidative and inhibitory activities against carbohydrate digestive enzymes of the infusion were determined using established protocols. The liver tissues of rats were used for glucose uptake assay and to evaluate the infusion’s effect on endogenous antioxidant, glucogenic, and nucleotide hydrolyzing enzyme activities in FeSO4-induced hepatic injury. Results: The Harpephyllum caffrum infusion significantly reduced ferric iron (FRAP) and free radicals (OH• and DPPH) in a dose- dependent manner. It inhibited α-amylase and α-glucosidase activities and increased glucose uptake in hepatic tissues. FeSO4 significantly decreased glutathione concentration, catalase, and superoxide dismutase activities while increasing malondialdehyde level, glycogen phosphorylase, fructose-1,6-bisphosphatase, and adenosine triphosphatase activities. However, treatment with Harpephyllum caffrum infusion reversed FeSO4-induced changes. Characterization of the infusion revealed the presence of catechol, O-pyrocatechuic acid, mequinol, maltol, and glycoside derivatives. Conclusions: The Harpephyllum caffrum infusion demonstrates antidiabetic and antioxidative potentials in in vitro models of type 2 diabetes as depicted by its ability to inhibit carbohydrate digestive enzymes, mitigate oxidative imbalance, and regulate glucogenic and nucleotide hydrolyzing enzyme activities in oxidative hepatic injury.

26-38

Authors: Fatiqa Zafar, Nazish Jahan, Shaukat Ali, Saba Jamil, Riaz Hussain, Saba Aslam

Objective: To enhance the pharmaceutical potential and oral bioavailability of quercetin contents of Allium cepa peel extract by novel nanosuspension technology. Methods: Nanoprecipitation approach was successfully used for the formulation of nanosuspension. To obtain pharmaceutical-grade nanosuspension with minimum particle size and polydispersity index, sodium lauryl sulphate was selected as a stabilizer. Important formulation parameters were statistically optimized by the response surface methodology approach. The optimized nanosuspension was subjected to stability and in vitro dissolution testing and characterized by scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, and zeta sizer. To evaluate the preeminence of nanosuspension over coarse suspension, comparative bioavailability studies were carried out in male albino rats. The pharmaceutical potential of developed nanosuspension was evaluated by antioxidant, antimicrobial, and toxicity studies. Results: The optimized nanosuspension showed an average particle size of 275.5 nm with a polydispersity index and zeta potential value of 0.415 and -48.8 mV, respectively. Atomic force microscopy revealed that the average particle size of nanosuspension was below 100 nm. The formulated nanosuspension showed better stability under refrigerated conditions. Nanosuspension showed an improved dissolution rate and a 2.14-fold greater plasma concentration of quercetin than coarse suspension. Moreover, the formulated nanosuspension exhibited enhanced antioxidant and antimicrobial potential and was non-toxic. Conclusions: Optimization of nanosuspension effectively improves the pharmaceutical potential and oral bioavailability of Allium cepa extract.