Antioxidant and Cytotoxic Activities and Phytochemical Analysis of Euphorbia wallichii Root Extract and its Fractions

Abstract Euphorbia wallichii a perennial herb growing mainly in Himalayas has been widely used in folk medicines for its medicinal properties. In the present study, the crude methanolic root extract (CME) and its fractions; n-Hexane Fraction (NHF), n-Butanol Fraction (NBF), Chloroform Fraction (CHF), Ethyl acetate Fraction (EAF) and Aqueous Fraction (AQF) of this plant specie were investigated for antioxidant and cytotoxic activities and phytochemical analysis. Antioxidant activity was determined by using 2,2-diphenyl-1-picryl-hydrazyl free radical (DPPH) and DNA protection assay performed on pBR322 plasmid DNA. In both these assays, promising results were obtained for CME as well as other fractions. The IC 50 values for DPPH assay were in a range of 7.89 to 63.35 µg/ml in which EAF showed the best antioxidant potential and almost all the tested samples showed certain level of DNA protection. The cytotoxic activity was assessed by using Sulforhodamine B (SRB) assay on human cell lines; H157 (Lung Carcinoma) and HT144 (Malignant Melanoma). The IC 50 values of the tested samples ranged from 0.18 to 1.4 mg/mL against H157 cell line whereas against HT144 cell line the IC 50 values ranged from 0.46 to 17.88 mg/mL with NBF fraction showing maximum potential for both. Furthermore, the phytochemical analysis of CME and its fractions showed the presences of flavonoids, saponins, tannins, terpenoides and cardiac glycosides with varying concentrations

Novel Strategy of Lactide Polymerization Leading to Stereocomplex Polylactide Nanoparticles Using Supercritical Fluid Technology

The enantiomeric crystallization of polylactides has removed the limitations of innate poor thermal and mechanical properties of the homopolymers. The supercritical fluid technology is an emerging panoramic version of biomedical polymer synthesis and has proven to be a domineering substitute to toxic organic solvents. Herein, we report an intriguing, efficient and a novel polymerization process using supercritical dimethyl ether (sc-DME) for preparation of polylactides leading to the stereocomplex polylactide (s-PLA) nanoparticles. The process has generated high molecular weight homopolymers (Mn ≥ 200 000 g mol^–1) starting from monomers which ultimately crystallized to a dry powder of s-PLA nanoparticles. The optimum processing parameters are d/l-lactide polymerization using sc-DME at 130 °C, 400 bar for 5 h with a 30% monomer concentration, keeping the ratio [monomer]:[tin­(II)­2-ethylhexanoate]:[1-dodecanol] as 3000:1:1 while the stereocomplexation as sc-DME at 70 °C, 350 bar for 2 h. We have investigated the effects of monomer concentration, molecular weights of homopolymers, times, temperatures, and pressures on the degree of stereocomplexation. The degree of s-PLA was analyzed by DSC and XRD. The s-PLA has improved melting point and thermal degradation than homopolymers. The Young’s modulus of s-PLA increased to 1.4 GPa with tensile strength (∼43 MPa) higher than homopolymers (∼13 MPa) with 3.2% elongation at break. The dry s-PLA powder shows a diversity of particle size ranging from 30 to 600 nm analyzed by SEM. The s-PLA finds potential applications in polymer nanofabrication, biomedical stents and encapsulation, melt-blending, solution casting, and molding