In vitro xanthine oxidase inhibition by selected Jordanian medicinal plants

In the present study, 18 Jordanian medicinal plants were evaluated for their Xanthine Oxidase [XO] inhibitory potential. Their aqueous extracts, prepared from used parts, were tested in vitro, at 200 micro g/mL concentration, for their inhibition potencies expressed as% inhibition of XO activity. Five of the tested plants were found most active [% inhibition more than 35%] and their inhibition profiles [dose-dependent] were further evaluated by estimating the IC[50] values of their corresponding extracts. These plants were Hyoscyamus reticulates L. [IC[50] = 12.8 micro g/mL], Achillea fragrantissima [Forssk.] Sch. Bip. [197.6 micro g/mL], Pimpinella anism L., [300.4 micro g/mL]. Origanum syriacum L. [317.0 micro g/mL], and Origanum vulgare L. [403.9 micro g/mL]. Moreover, five more plants showed XO inhibitory activity in the range of 14-30%. Namely: Daphne linearifolia L. [29.5% inhibition], Hibiscus sabdoriffa L. [19.44], Aristolochia maurorum L. [15.6%], Citrullus colocynthis [L.] Schr. [14.4%], and Laurus nobilis L. [13.97%]. Considering the results of the present screening study, many of the investigated plants species can be used as potential sources of natural XO inhibitors that can be elaborated as successful herbal remedies for gout, arthritis and other XO-related disorders

comparative enzymatic inhibition assay as a surrogate indicator of pharmaceutical and potency equivalence of two orlistat formulations

The most practical measure of therapeutic equivalence between two commercially available and generic formulation of a certain drug is to determine their in vivo bioavailability. However, for the oral dosage form that is not intended to be absorbed [e.g. orlistat], in vivo bioavailability studies are irrelevant to the achievement of the product's intended purposes. However, specific requirements for these drug products may be set in a way that they should meet acceptable in vitro standards. For this purpose, a comparative enzymatic inhibition assay of the target enzyme, pancreatic lipase, was developed to demonstrate orlistat products' pharmaceutical and potency equivalence. In this study we compared the pancreatic lipase inhibition that is achieved by two orlistat formulations; a generic product manufactured by local company [Jordan Sweden Medical Company, JOSWE] and the reference one Xenical manufactured by Roche. The inhibition was expressed by the concentration of product which inhibits 50% of the activity of the pancreatic lipase enzyme [IC[50]]. The results of these studies showed that both formulations have equivalent potency that was demonstrated by in vitro studies