In vitro bacterial cytotoxicity of CNTs: reactive oxygen species mediate cell damage edges over direct physical puncturing.

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.

Antioxidant activity and free radical scavenging capacity of phenolic extracts from Helicteres isora L. and Ceiba pentandra L.

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.

Antitumor activity of the methanolic extract of Ammannia baccifera L. against Dalton's ascites lymphoma induced ascitic and solid tumors in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: India is a rich source of medicinal plants and a number of plant extracts are used against diseases in various systems of medicine such as Ayurveda, Unani and Siddha. Only a few of them have been scientifically explored. One of such plants is Ammannia baccifera L., traditionally used as an antitumor agent. AIM OF THE STUDY: The objective of the present study was to explore the anticancer activity of the methanol extract of A. baccifera against Dalton's ascites lymphoma (DAL)-bearing Swiss albino mice and in vitro cytotoxicity against human cervical cancer cell line (HeLa). MATERIALS AND METHODS: In vitro cytotoxic effects of A. baccifera was evaluated against HeLa and NIH 3T3 cells using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] method. Anticancer activity of the extract was evaluated in Swiss albino mice against DAL cell line at the doses of 100 and 200mg/kg p.o. The extract was administered to animals for 14 consecutive days. After 12h fasting from last dose, the mice were sacrificed and the anticancer effect of A. baccifera was assessed by evaluating tumor volume, viable and nonviable tumor cell count, tumor weight, hematological parameters and certain antioxidant biochemical parameters against DAL bearing control group. RESULTS: The extract of A. baccifera was cytotoxic to the HeLa cancer cell line but relatively non-toxic to the normal cell line NIH 3T3. A. baccifera extract treatment resulted in significant decreases in tumor volume, viable cell count and tumor weight and enhanced the life span of DAL bearing mice. Hematological parameters such as RBC, hemoglobin and lymphocyte count reverted to normal level in A. baccifera treated mice. The extract also significantly (p<0.05) decreased the levels of lipid peroxidation and increased the activities of GSH, GPx, SOD and CAT. The anticancer effects of the A. baccifera extract is comparable with that of the standard drug 5-Fluorouracil. CONCLUSION: The results showed that the methanol extract of A. baccifera is effective in inhibiting the tumor growth in ascetic models that is comparable to 5-fluorouracil. This plant has potential in the development of anticancer therapy and this study scientifically validated the folklore use of this plant.

Antioxidant, anti-inflammatory and anti-nociceptive effects of Ammannia baccifera L. (Lythracceae), a folklore medicinal plant.

ETHNOPHARMACOLOGICAL RELEVANCE: Ammannia baccifera L. has been reported as folklore remedy for the treatment of inflammation and tumor in the state of Rajasthan, India. AIM OF THE STUDY: The present study was designed to investigate the antioxidant, anti-inflammatory and anti-nociceptive effects of the methanol extract from the aerial parts of Ammannia baccifera under in vitro and in vivo models. MATERIALS AND METHODS: The in vitro antioxidant activity of the extract was measured using DPPH, superoxide, hydroxyl and nitric oxide radicals. The anti-inflammatory activity was evaluated using carrageenan induced paw edema. Analgesic activity of the methanol extract was estimated against acetic acid-induced writhing and hot plate methods. RESULTS: The IC(50) value for free radical scavenging activity of this extract was significantly superior over the positive standards butylated hydroxyl anisole (BHA) and rutin. The extract exhibited significant anti-inflammatory and analgesic activities at the dose of 100 and 200mg/kg p.o. The analgesic effect of the higher dose of the extract (200mg/kg) was comparable with the standard drugs aspirin and morphine. CONCLUSION: The present study scientifically validated the traditional use of this plant against inflammation.

Evaluation of Indian sacred tree Crataeva magna (Lour.) DC. for antioxidant activity and inhibition of key enzymes relevant to hyperglycemia.

In the present investigation, leaf and stem bark of Crataeva magna are evaluated for their antioxidant activity and inhibition of key enzymes relevant to hyperglycemia. Both the parts exhibited significant antioxidant and anti-α-glucosidase activity. The results will lead in favor of the use of this plant as a potential additive/nutraceutical antioxidant compound.

Protective effects of methanolic extract of Hedyotis puberula (G. Don) R. Br. ex Arn. against experimentally induced gastric ulcers in rat.

AIM OF THE STUDY: This study was aimed to evaluate the antiulcer activity of the whole plants of Hedyotis puberula (G. Don) R. Br. ex Arn. MATERIALS AND METHODS: Gastroprotective potential of the Hedyotis puberula methanol extract (200 and 400mg/kg body weight) was studied on indomethacin (IND), ethanol and pyloric ligation (PL)-induced gastric ulcer models in rats. RESULTS: The treatment with Hedyotis puberula extract at 400mg/kg p.o. protected the rats against the ulceration which was comparable to the reference drug omeprazole. Pretreatment with extract protected rats from gastric lesion development by way of increased pH and decreased volume, acidity and pepsin content of gastric secretion. Furthermore, total carbohydrate: protein ratio of the gastric juice were noticeably increased in pretreated rats. CONCLUSION: Results of our study showed that Hedyotis puberula possess significant gastroprotective activity and validate the folklore claim.

Evaluation of analgesic and anti-inflammatory potential of Hedyotis puberula (G. Don) R. Br. ex Arn. in experimental animal models.

Hedyotis puberula (G. Don) R. Br. ex Arn. is used for the treatment of several ailments in the traditional system of medicine. In the present study, the methanol extract of the whole plant (200 and 400 mg/kg) exhibited significant analgesic and anti-inflammatory activities in a dose dependent manner. The analgesic effect, evaluated in mice in hot plate as well as acetic acid-induced writhings, were higher than the standard drugs pentazocine (30 mg/kg) and indomethacin (5 mg/kg), respectively. Further, the methanol extract at the dose of 400mg/kg produced significant inhibition of carrageenan induced paw edema and reduced the weight of granuloma in cotton pellet-induced granuloma pouch model.

Effect of dried fruits of Solanum nigrum LINN against CCl4-induced hepatic damage in rats.

Ethanol extract of Solanum nigrum LINN was investigated for its hepatoprotective activity against CCl4-induced hepatic damage in rats. The ethanol extract showed remarkable hepatoprotective activity. The activity was evaluated using biochemical parameters such as serum aspartate amino transferase (AST), alanine amino transferase (ALT), alkaline phosphatase (ALP) and total bilirubin. The histopathological changes of liver sample in treated animals were compared with respect to control.