Showing papers by "Manipal University published in 1994"

Diminution of singlet oxygen-induced DNA damage by curcumin and related antioxidants.

Abstract: Curcumin, the natural antioxidant from turmeric, an Indian spice, and its derivatives have significant abilities to protect plasmid pBR322 DNA against single-strand breaks induced by singlet oxygen (1O2), a reactive oxygen species with potential genotoxic/mutagenic properties. 1O2 was generated at 37 degrees C in an aqueous buffer system by the thermal dissociation of the endoperoxide of 3,3'-(1,4-naphthylene)dipropionate (NDPO2). Among the compounds tested, curcumin was the most effective inhibitor of DNA damage followed by desmethoxycurcumin, bisdesmethoxycurcumin and other derivatives. The observed antioxidant activity was both time- and concentration-dependent. The protective ability of curcumin was higher than that of the well-known biological antioxidants lipoate, alpha-tocopherol and beta-carotene. However, the highest protective ability with saturating concentrations of curcumin did not exceed 50%. The ability of curcumin and its derivatives to protect DNA against 1O2 seems to be related to their structures and may at least partly explain the therapeutic and other beneficial effects of these compounds including anticarcinogenic and antimutagenic properties.

Antioxidant properties of dehydrozingerone and curcumin in rat brain homogenates.

Abstract: The present study investigates the inhibition of lipid peroxidation by dehydrozingerone and curcumin in rat brain homogenates. Both the test compounds inhibited the formation of conjugated dienes and spontaneous lipid peroxidation. These compounds also inhibited lipid peroxidation induced by ferrous ions, ferric-ascorbate and ferric-ADP-ascorbate. In all these cases, curcumin was more active than dehydrozingerone and dl-alpha-tocopherol.

Formulation and in vitro evaluation of vincristine encapsulated niosomes

Abstract: Vesicles containing vincristine were prepared using different nonionic surfactants and by employing different techniques The entrapment efficiency and the stability in terms of drug leakage of the noisomes prepared by different methods were compared Transmembrane pH gradient (inside acidic) drug uptake process (TMpH) was proved to be most satisfactory yielding 90 drug entrapment when span 40-cholesterol (1:1) were used as vesicle forming agents A relatively slow release pattern of the entrapped vincristine from the niosomes prepared by this method indicates an enhanced stability of the system

Dehydrozingerone and its analogues as inhibitors of nonenzymatic lipid peroxidation.

Abstract: The antioxidant property of dehydrozingerone and its analogs were investigated in the ferric-ascorbate induced lipid peroxidation model in rat brain homogenate. All the non phenolic compounds were either inactive or less active, while phenolic compounds with substitution at both meta positions were found to be more active than dehydrozingerone. Based on their IC50 values several of these compounds are more potent than vitamin E and hence may be of potential use in various diseases caused by oxidant stress.

(E)4-[4-N,N-Dimethylaminophenyl)but-3-en-2-one (DMAP) treatment inhibits the radiation-induced micronucleus formation in bone marrow of BALB/c mice

Abstract: The frequency of micronucleated polychromatic (MPCE) and normochromatic erythrocytes (MNCE) and polychromatic/normochromatic erythrocyte ratio (P/N ratio) was studied in the bone marrow of BALB/c mice administered with 20 mg/kg body weight of (E)4-[4-N,N-dimethylaminophenyl]but-3-en-2-one (DMAP), a phenyl-butenone derivative, 30 min before exposure to different doses of 60Co γ-radiation. A dose-dependent increase in the frequency of MPCE and MNCE was observed in double-distilled water (DDW) or oil + irradiated and DMAP + irradiated groups. The frequency of MPCE and MNCE was significantly less in the DMAP + irradiated group when compared to the DDW or oil + irradiated groups at all the irradiation doses studied. The P/N ratio declined with increasing radiation dose in DDW or oil + irradiated and DMAP + irradiated groups. The inhibitory effect of irradiation on the P/N ratio was less in the DMAP + irradiated group as compared to the DDW or oil + irradiated groups, as evidence by the higher P/N ratio in the former than the latter. The P/N ratio was significantly higher in the DMAP + irradiated group from 1 Gy irradiation onwards. The dose-response relationship was linear-quadratic for MPCE, MNCE and P/N ratio for all the groups studied.

Formulation and evaluation of controlled release dental implants of povidone iodine for periodontitis.

Abstract: Diseases of the periodontium continue to be one of the man's most wide spread afflictions. Periodontitis is one of such which is characterised by a periodontal pocket formed due to the inflammatory disease of gingiva and the deeper periodontal tissues. Local controlled release implants of povidone iodine was prepared using various polymers and stability, release characteristics, total drug content etc, were evaluated. The clinical studies of the dental implants were carried out on 10 patients.