Krishna Sharma

Microwave assisted synthesis, characterization and biological evaluation of palladium and platinum complexes with azomethines

Reactions of 3-acetyl-2,5-dimethylthiophene with thiosemicarbazide and semicarbazide hydrochloride resulted in the formation of new heterocyclic ketimines, 3-acetyl-2,5-dimethylthiophene thiosemicarbazone (C(9)H(13)N(3)OS(2) or L(1)H) and 3-acetyl-2,5- dimethylthiophene semicarbazone (C(9)H(13)N(3)OS or L(2)H), respectively. The Pd(II) and Pt(II) complexes have been synthesized by mixing metal salts in 1:2 molar ratios with these ligands by using microwave as well as conventional heating method for comparison purposes. The authenticity of these ligands and their complexes has been established on the basis of elemental analysis, melting point determinations, molecular weight determinations, IR, (1)H NMR and UV spectral studies. These studies showed that the ligands coordinate to the metal atom in a monobasic bidentate manner and square planar environment around the metal atoms has been proposed to the complexes. Both the ligands and their complexes have been screened for their antimicrobial activities. The antiamoebic activity of both the ligands and their palladium compounds against the protozoan parasite Entamoeba histolytica has been tested.

Evaluation of the free radical scavenging activity and radioprotective efficacy of Grewia asiatica fruit

The radioprotective effect of Grewia asiatica fruit (GAE) which contains anthocyanin-type cyanidin 3-glucoside, vitamins C and A, minerals, carotenes and dietary fibre was studied. For the study Swiss albino mice were divided into five groups: (1) control (vehicle treated); (2) GAE treated (700 mg kg(-1) day(-1) for 15 days); (3) irradiated (5 Gy); (4) GAE+irradiated and (5) irradiated+GAE treated. The irradiation of animals resulted in a significant elevation of lipid peroxidation in terms of thiobarbituric acid reactive substances (TBARS) content and depletion in glutathione (GSH) and protein levels at all intervals studied, namely 1-30 days, in comparison to the control group. Treatment of mice with GAE before and after irradiation caused a significant depletion in TBARS content followed by a significant elevation in GSH and protein concentration in the intestine and testis of mice at all post-irradiation autopsy intervals in comparison to irradiated mice. Significant protection of DNA and RNA in testis was also noticed. GAE was found to have strong radical scavenging activity in 2,2-diphenyl-1-picrylhydrazyl (DPPH(*)) and O(2)(-) assays and also showed in vitro radioprotective activity in protein carbonyl assay in a dose-dependent manner. The above results prove the radioprotective efficacy of GAE.

Spinacia oleracea Modulates Radiation-Induced Biochemical Changes in Mice Testis

The present study is an attempt to investigate the radioprotective efficacy of spinach against radiation induced oxidative stress, since its leaves are rich in antioxidants like carotenoids (β-carotene, lutein and zeaxanthin) and high content of proteins, minerals, vitamin C. For the experimental study, healthy Swiss mice were selected from an inbred colony and divided into four groups. Group I (normal) it did not receive any treatment. Group II (drug treated) was orally supplemented with extract of spinach extract once daily at the dose of 1100 mg/kg for fifteen consecutive days. Group III (control) received distilled water orally equivalent to spinach extract for fifteen days than exposed to 5 Gy of gamma radiation. Group IV (experimental) was also administered orally with spinach extract for 15 consecutive days once daily. Thereafter, exposed to single dose of 5Gy of gamma radiation. After the exposure mice were than sacrificed at different autopsy intervals viz. 1, 3, 7, 15 and 30 days. Testis was removed for various biochemical estimations viz. LPO, protein, cholesterol and glycogen. Radiation induced augmentation in lipid peroxidation, glycogen and cholesterol values were significantly ameliorated by supplementation of SE extract, whereas radiation induced deficit in protein content could be elevated. This indicates that spinach extract pre - treatment renders protection against various biochemical changes in the mice testis to some extent if taken continuously which might be due to synergistic effect of antioxidant constituents present in the spinach.

Palladium(II) and platinum(II) derivatives of benzothiazoline ligands: Synthesis, characterization, antimicrobial and antispermatogenic activity.

A series of Pd(II) and Pt(II) complexes with two N(∩)S donor ligands, 5-chloro-3-(indolin-2-one)benzothiazoline and 6-nitro-3-(indolin-2-one)benzothiazoline, have been synthesized by the reaction of metal chlorides (PdCl2 and PtCl2) with ligands in 1:2 molar ratios. All the synthesized compounds were characterized by elemental analyses, melting point determinations and a combination of electronic, IR, 1H NMR and 13C NMR spectroscopic techniques for structure elucidation. In order to evaluate the effect of metal ions upon chelation, both the ligands and their complexes have been screened for their antimicrobial activity against the various pathogenic bacterial and fungal strains. The metal complexes have shown to be more antimicrobial against the microbial species as compared to free ligands. One of the ligands, 5-chloro-3-(indolin-2-one)benzothiazoline and its corresponding palladium and platinum complexes have been tested for their antifertility activity in male albino rats. The marked reduction in sperm motility and density resulted in infertility by 62-90%. Significant alterations were found in biochemical parameters of reproductive organs in treated animals as compared to control group. It is concluded that all these effects may finally impair the fertility of male rats.

Sulfur-Bonded Coordination Compounds of Palladium(II) and Platinum(II) and Their Antimicrobial Activity

The synthetic, spectroscopic, and biological studies of some new palladium(II) and platinum(II) complexes derived from biologically active sulfur donor ligands 1H-indol-2,3-dione benzothiazoline (Bzt 1 H) and 5-nitro-1H-indol-2,3-dione benzothiazoline (Bzt 2 H) have been described. The reactions were carried out in 1:2 molar ratios. The authenticity of the benzothiazolines and their complexes has been established on the basis of elemental analyses; molecular weight determinations; and IR, 1 H NMR, 13 C NMR, and UV spectral studies. Based on IR and 1 H NMR spectral studies, a square-planar structure has been assigned to these complexes. Studies were conducted to assess the comparative growth inhibiting potential of the synthesized complexes against the benzothiazolines for a variety of fungal and bacterial strains. The studies demonstrate that the ligands and complexes possess antimicrobial properties. Further, it was noted that the growth-inhibiting potential of the complexes is greater than the parent benzothiazolines.

New coordination compounds of some rare-earth metal complexes with sulfur and nitrogen Schiff bases and their in vitro antibacterial and antifungal properties

A series of rare-earth metal complexes with Schiff bases have been prepared by the interactions of hydrated lanthanide(III) chloride with the sodium salts of 1-(2-thienyl)ethanone hydrazinecarbothioamide (L1H) and 1-(2-thienyl)ethanonehydrazinecarboxamide (L2H) in 1:3 molar ratios and characterized by their elemental analyses, molar conductance and IR, NMR (1H and 13C) electronic and EPR spectral studies. The spectral data suggested that the complexes have a hexa-coordinated environment around the central metal atoms. Elemental analyses and NMR spectral data of the ligands and their metal(III) complexes agree with their proposed structures. The synthesized Schiff bases and their new metal complexes have been screened for in vitro antibacterial activity against Gram-negative (Escherichia coli) and Gram-positive (Pseudomonas cepacicola) bacterial strains and for in vitro antifungal activity against Fusarium oxysporum and Macrophomina phaseolina. All compounds showed significant antibacterial and antifungal activities against microbial species.

Biologically Potent Azomethine Complexes of Palladium(II) and Platinum(II)

The sulfur-nitrogen donor ligand, 1-acetylferrocenehydrazinecarbothioamide (L 1 H) and oxygen-nitrogen donor ligand, 1-acetylferrocenehydrazinecarboxamide (L 2 H) have been synthesized by condensation of 1-acetylferrocene with corresponding hydrazinecarbothioamide and hydrazinecarboxamide, respectively. The structure determination of palladium(II) and platinum(II) complexes was performed by elemental analysis, melting point determinations, conductivity measurements, molecular weight determinations, IR, 1 H NMR and UV spectral studies. Based on these studies the square planar environment around the metal atoms has been proposed. Studies were also conducted to assess the comparative growth- inhibiting potential of the synthesized complexes and the azomethines against a variety of fungal and bacterial strains.

Microwave synthesis, antimicrobial and antiamoebic activity of palladium and platinum complexes

Microwave synthesis represents one of the important dimensions of modern chemistry attracting a considerable amount of attention. A biologically potent Schiff base derived from 3-acetyl-2,5-dimethylthiophene and 2-aminothiophenol and its Pd(II) and Pt(II) metal complexes of the type [M(Bzt)2] (where M = Pd/Pt and Bzt = deprotonated ligand) have been synthesized by thermal as well as Microwave assisted synthesis and characterized by their elemental analyses and IR, 1H NMR and electronic spectral studies. These studies showed that the ligand coordinated to the metal atom in a monobasic bidentate manner and square-planar environment around the metal atoms has been proposed to the complexes. The synthesized Schiff base and its new metal complexes have been screened for in-vitro antibacterial activity against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacterial strains, and for in-vitro antifungal activity against Fusarium oxysporum and Aspergillus niger. All compounds showed significant antibacterial and antifungal activities against microbial species. The antiamoebic activity of the ligand and its palladium compound against the protozoan parasite entamoeba histolytica has been tested and results showed that compound might be endowed with important antiamoebic properties.