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This study aimed to evaluate the antioxidant activity and total phenolic content (TPC) and total flavonoid content (TFC) of crude extracts obtained from three Asclepiadaceae species, namely, Calotropis procera L., Peruglaria tomentosa L., and Pentatropis spiralis (Forsk.) Decne. Both butanol and aq. methanol extracts of the three species showed the highest amount of phenol and flavonoid contents, which exhibited the greatest antioxidant activity in the scavenging of 2,2-diphenyl-2-picrylhydrazyl free radical (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical cation (ABTS), ferrous chelating effect (FIC), and hydroxyl radical (HDR) assays. Phytochemical screening of the extracts revealed the presence of alkaloids, tannins, sponins, flavonoids, terpenoids, and glycosides. LC-MS analysis was carried out to identify the major compounds from each crude extract. A total of 12 phenolic compounds in the extracts of the 3 species were identified and quantified, including 9 flavonoids, 2 hydroxybenzoic acids, and 3 hydroxycinnamic acids. The current study also revealed a good correlation between total phenolic contents and the observed antioxidant activity of the crude extracts.

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.

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A thorough computational study of a thermal degradation mechanism of 2-ethoxyethanol (2-EE) in the gas phase has been implemented using G3MP2 and G3B3 methods. The stationary point geometries were optimized at the B3LYP functional utilizing the 6-31G­(d) basis set. Intrinsic reaction coordinate analysis was performed to determine the transition states on the potential energy surfaces. Nineteen primary different reaction mechanisms, along with the kinetic and thermodynamic parameters, are demonstrated. Most of the thermal degradation mechanisms result in a concerted transition state step as an endothermic process. Among 11 degradation pathways of 2-ethoxyethanol, the formation of ethylene glycol and ethylene is kinetically significant with an activation energy of 269 kJ mol–1 at the G3B3 method. However, the kinetic and thermodynamic calculations indicate that ethanol and ethanal’s formation is the most plausible reaction with an activation barrier of 287 kJ mol–1 at the G3B3 method. For the bimolecular dissociation reaction of 2-ethoxyethanol with ethanol, the pathway that produces ether, H2, and ethanol is more likely to occur with a lower activation energy of 221 kJ mol–1 at the G3B3 method. Thus, 2-EE has experienced a set of complex unimolecular and bimolecular reactions.