Antioxidant and cytoprotective properties of loganic acid isolated from seeds of Strychnos potatorum L. against heavy metal induced toxicity in PBMC model.

Present work carried out with the objectives to isolate active component of S. potatorum and also to evaluate its free radical scavenging activity and preventing capacity against heavy metal toxicity. Solvents of different polarity were used to prepare crude extracts of S. potatorum seeds and screened for antioxidant activity. Among the crude extracts, methanolic extract was found to exhibit higher antioxidant activity (81.22%) which was fractionated by liquid-liquid partitioning method. Among the different fractions (LF1-LF4), LF-2 showed higher antioxidant activity (98.24%) as compared to other three liquid fractions and hence LF-2 was further purified by column chromatography. Among nine column fractions (CF1-CF9), fraction CF-7 was found to have higher antioxidant activity (92.14%), which was further analyzed using LC-MS and NMR and identified as loganic acid. In vitro radical scavenging assays showed remarkable antioxidant activity of loganic acid in terms of DPPH scavenging (IC50 149 µg/ml), superoxide radical scavenging (IC50 632.43 µg/ml) and hydroxyl radical scavenging (IC50 29.78 µg/ml). Loganic acid exhibited 81% prevention of heavy metal toxicity through the mechanism of inhibiting ROS generation (2046 AU vs. 5264 AU in control) and lipid peroxidation (95.01%). Thus, the active compound (loganic acid) isolated from S. potatorum has strong free radical scavenging activity and remarkable cyto-protective effect against heavy metal mediated toxicity.

Dendritic poly(ether imine) based gene delivery vector.

The nonviral vector based gene delivery approach is attractive due to advantages associated with molecular-level modifications suitable for optimization of vector properties. In a new class of nonviral gene delivery systems, we herein report the potential of poly(ether imine) (PETIM) dendrimers to mediate an effective gene delivery function. PETIM dendrimer, constituted with tertiary amine branch points, n-propyl ether linkers and primary amines at their peripheries, exhibits significantly reduced toxicities, over a broad concentration range. The dendrimer complexes pDNA effectively, protects DNA from endosomal damages, and delivers to the cell nucleus. Gene transfection studies, utilizing a reporter plasmid pEGFP-C1 and upon complexation with dendrimer, showed a robust expression of the encoded protein. The study shows that PETIM dendrimers are hitherto unknown novel gene delivery vectors, combining features of poly(ethylene imine)-based polymers and dendrimers, yet are relatively nontoxic and structurally precise.