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In the present study, antioxidant activities of the phenolic extracts from H. isora fruits and C. pentandra seeds were investigated by employing established in vitro systems, which included reducing power, OH(●), DPPH(●), ABTS(●+), linoleic acid emulsion, metal chelation and antihemolytic activity. The extracts of C. pentandra contained relatively higher levels of total phenolics and flavonoids than those of H. isora. All the extracts showed dose dependent reducing power activity and moreover, they were well correlated with the total phenolic substances. A similar dose dependant trend has also been observed for hydroxyl radical scavenging activity and DPPH(●) radical scavenging activity. Further, addition of 250 μg of extracts to the reaction mixture produced 41.3-54.6% peroxidation inhibiting activity during 60 h of incubation. The potential of multiple antioxidant activity of samples can be further evidenced by inhibition of reactive oxygen mediated erythrocyte cell lysis and metal ion chelating activity.

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Numerous medicinal plants and their formulation are used for liver disorders in ethnomedical practice as well as traditional system of medicine in India.1) Herbs play a vital role in the management of various liver disorders. In the absence of a reliable liver protective drug in the modern medicine, a number of medicinal preparation in ayurvedha are recommended for the treatment of liver disorders.2) The present work was taken up to evaluate the effects of ethanol extract of the dried fruits of Solanum nigrum L. against CCl 4 -induced hepatic damage in rats.Solanum nigrum (Family : Solanceae) is a shrub found throughout India, which is traditionally used for inflammatory, diuretic and liver disorders.3) The phytochemical studies revealed the presence of an alkaloid called solamargine, nigrumnin I, nigrumnin II 4) and a glycoside named solasodine. 5) MATERIALS AND METHODS MaterialsThe fruits of Solanum nigrum were collected from Kolli hills, Namakkal District, Tamil Nadu in the month of November and authenticated at the Botanical Survey of India, Coimbatore, India. The fruits were washed and cut into small pieces, shade dried and powdered. The coarse powder was subjected to continuous hot extraction in a soxhlet by using ethanol (95% v/v). The ethanol was removed by distillation under reduced pressure. These extracts were suspended in 5% gum acacia and used in the present experiments. LD 50 value for the ethanol extract of S. nigrum fruits was determined in Swiss albino mice as described by Miller and Tainter. 6)Animals Male albino rats were procured from Perundurai Medical College, Perundurai and bred in the college animal house. They were fed on commercial diet (Hindustan lever, Bangalore) and water ad libitum during the experiments. The room temperature was maintained at 25Ϯ1°C. Three groups (I-III) each comprising of six animals weighing between 130-160 g were selected. Group I served as control and received 0.2 ml of gum acacia daily for 7 d orally. Group II rats were similarly treated as group I. Groups III were treated with ethanol extract of S. nigrum fruits at a dose of 250 mg/kg respectively for 7 d. 7)On the seventh day carbon tetrachloride (1.25 ml/kg, p.o.) was administered 30 min after the last dose to all rats except rats in group I. After 36 h, all the rats were sacrificed under light ether anesthesia, blood was collected in sterile centrifuge tube and allowed to clot. Serum was separated by centrifuging at 2500 rpm for 15 min and used for the estimation of serum aspartate amino transferase (AST), 8) alanine amino transferase (ALT), 8) alkaline phosphatase (ALP) 9) and total bilirubin. 10)After the animals were sacrificed, the abdomen of each was cut opened and the liver removed. The ratio of wet liver weight per 100 g of animal body weight was calculated. The livers were preserved in neutral buffered formalin and were processed for paraffin embedding, following the standard microtechnique.11) Five micron sections of livers, stained with alum haemotoxylin and eosin were observed under microscope f...

Understanding the bacterial cytotoxicity of CNTs is important for a wide variety of applications in the biomedical, environmental, and health sectors. A majority of the earlier reports attributed the bactericidal cytotoxicity of CNTs to bacterial cell membrane damage by direct physical puncturing. Our results reveal that bacterial cell death via bacterial cell membrane damage is induced by reactive oxygen species (ROS) produced from CNTs and is not due to direct physical puncturing by CNTs. To understand the actual mechanism of bacterial killing, we elucidated the bacterial cytotoxicity of SWCNTs and MWCNTs against Gram-negative human pathogenic bacterial species Escherichia coli, Shigella sonnei, Klebsiella pneumoniae, and Pseudomonas aeruginosa and its amelioration upon functionalizing the CNTs with antioxidant tannic acid (TA). Interestingly, the bacterial cells treated with CNTs exhibited severe cell damage under laboratory (ambient) and sunlight irradiation conditions. However, CNTs showed no cytotoxicity to the bacterial cells when incubated in the dark. The quantitative assessments carried out by us made it explicit that CNTs are effective generators of ROS such as (1)O2, O2(•-), and (•)OH in an aqueous medium under both ambient and sunlight-irradiated conditions. Both naked and TA-functionalized CNTs showed negligible ROS production in the dark. Furthermore, strong correlations were obtained between ROS produced by CNTs and the bacterial cell mortality (with the correlation coefficient varying between 0.7618 and 0.9891) for all four tested pathogens. The absence of bactericidal cytotoxicity in both naked and functionalized CNTs in the dark reveals that the presence of ROS is the major factor responsible for the bactericidal action compared to direct physical puncturing. This understanding of the bactericidal activity of the irradiated CNTs, mediated through the generation of ROS, could be interesting for novel applications such as regulated ROS delivery in cancer therapy and the sanitation of potable water supplies.