Background Juniperus Phoenicea (JP) and Calicotome Villosa (CV) are used by Jordanian populations as herbal remedies in traditional medicine. Herein, the phytochemical contents of their methanolic extracts were analyzed and their antioxidant as well as in vitro anti- β-Galactosidase activities were evaluated; their effect on β-Galactosidase enzyme kinetics was evaluated and the thermodynamic of the enzyme was determined. Methods The antioxidant activity of JP and CV crude methanolic extracts was evaluated using 1,1-diphenyl,2-picrylhydrazyl (DPPH) free radical scavenging and ferric reducing antioxidant power (FRAP) assays; however, the effect of the plants’ crude extracts on β-Galactosidase activity and kinetics was evaluated in vitro. Moreover, total phenolic, flavonoids, and flavonols content in plants’ extracts were determined and expressed in Gallic acid equivalent (mg GAE/g dry extract) or rutin equivalent (mg RE/g dry extract). Results Phytochemical screening of the crude extracts of JP and CV leaves revealed the presence of phenols, alkaloids, flavonoids, terpenoids, anthraquinones, and glycosides. Flavonoids and flavonols contents were significantly higher in JP than in CV (p < 0.05). Furthermore, an analogous phenolic content was detected in both JP and CV methanolic extracts (103.6 vs 99.1 mg GAE/g extract). The ability of JP extract to scavenge DPPH radicals was significantly higher than that of CV extract with IC50 = 11.1 μg/ml and 15.6 μg/ml, respectively. However, their extracts revealed relatively similar antioxidant capacities in FRAP assay; their activity was concentration dependent. The JP extract inhibited β—galactosidase enzyme activity with a significant IC50 value compared to CV extract; they exhibited their inhibitory activities at IC50 values 65 µg/ml and 700 µg/ml, respectively. Rutin revealed anti-β-galactosidase activity at IC50 = 75 µg/ml. The mode of inhibition of β-galactosidase by JP, CV, and rutin was non-competitive, mixed, and competitive inhibition, respectively. Thermodynamic and enzyme inactivation kinetics revealed that β-galactosidase has a half-life time of 108 min at 55 °C, activation energy of 208.88 kJ mol−1 and the inactivation kinetics follows a first-order reaction with k-values 0.0023–0.0862 min−1 and positive entropy of inactivation (∆S°) values at various temperatures, indicating non-significant processes of aggregation. Conclusions The methanolic extracts of JP and CV possess anti-hyperglycemic and antioxidant activities with potential pharmaceutical applications.

Background: We investigated Juniperus Phoenicea (J. Phoenicea) and Calicotome Villosa (C. Villosa) from Jordan for phenolic contents, antioxidant, anti β-Galactosidase activities, in an attempt to rationalize its use in lactose metabolism disorders. The kinetic parameters of leave extracts, galactose, glucose, fructose and acarbose were evaluated. Also, the thermodynamic parameters of the enzyme thermal inactivation were determined. Methods: JP and cv crude methanolic extracts were evaluated for 1,1-diphenyl,2-picrylhydrazyl (DPPH) free radical scavenging activity and ferric reducing antioxidant power (FRAP). Further, β-Galactosidase inhibitory activities were performed using O-nitrophenyl-beta-D-galactopyranoside as substrate. Moreover, total phenolic contents, flavonoids and flavonols of plants extracts were determined and expressed in mg of gallic acid equivalent (mg GAE/g dry extract) or rutin equivalent per gram of dry extract (mg RE/g dry extract).Results: Phytochemical screening of the crude extract of J. Phoenicea and C. Villosa leaves contained phenols, alkaloids, flavonoids, terpenoids, anthraquinones and glycosides. J. Phoenicea exhibited high flavonoids and flavonols contents than C. Villosa but both J. Phoenicea and C. Villosa contained high phenolic and showed concentration dependent DPPH scavenging activity, with J. Phoenicea (IC50 =11.1 μg/ml), C. Villosa (IC50 =15.6 μg/ml), respectively. According to FRAP assay, the antioxidant power activity of plants extracts was concentrations dependent. The β-galactosidase % inhibition was increased as the concentration of of J. phoenicea, C. villosa and rutin increased. The mode of inhibition of β-galactosidase by J. phoenicea (IC50= 65 µg/ml) and C. villosa (IC50= 700 µg/ml) extracts was non-competitive and mixed-inhibition, respectively. Also, rutin was affected in a competitive (IC50 = 75 µg/ml) inhibition. β-galactosidase half-life was 108 min at 55°C, thermodynamic parameters revealed an activation energy of 208.88 kJ mol-1 and the inactivation kinetic follows a first-order reaction with k-values ranges between 0.0862 and 0.0023 min-1. The enzyme showing a decreasing trend of enthalpy of denaturation (∆H°) as temperature increase but value of free energy of thermal denaturation (∆G°) for β-galactosidase was decreased with increasing in temperature. The calculated entropy of inactivation (∆S°) at each temperature showed positive values, which means there are no significant processes of aggregation.Conclusions: J.phoenicea and C.villosa have inhibiting effect on β-galactosidase activity. Thermodynamic approach shows an enzyme stable and suggests that inactivation mechanism is based on molecular structural changes.