A novel hepatoprotective activity of Alangium salviifolium in mouse model.

In this study, the hepatoprotective activity of methanol bark extract of Alangium salviifolium (BEA) was evaluated for biochemical and histological parameters in swiss albino mice with CCl4-induced hepatotoxicity. The hepatomodulatory effect of two doses of BEA (20 and 50 mg/kg bw for 15 days by oral gavage) was assessed on antioxidant enzymes, phase I and phase II drug detoxifying enzymes. For the characterization of the extract, GC-MS analysis was performed that revealed the abundance of alkaloids and steroidal compounds. Total phenolic and flavonoid contents in BEA were 69.61 ± 0.18 mg GAE/g and 46.27 ± 3.44 mg Rutin/g, respectively. BEA administration decreased the levels of AST, ALT, and ALP, which were elevated due to hepatic damage by CCl4. BEA significantly decreased the lipid peroxidation, activities of LDH, and phase I enzymes including cytochrome P450 reductase, cytochrome b5 reductase while increased the activities of SOD, CAT, and phase II enzymes DT-diaphorase and glutathione S-transferase in liver. Further, histological evaluation of the liver tissue was suggestive of the protective effect of BEA against CCl4 toxicity. Together, these results suggest that BEA has strong hepatoprotective activity in mice which may also be attributed to its potential chemopreventive efficacy.

Integrin expression and glycosylation patterns regulate cell-matrix adhesion and alter with breast cancer progression.

Integrins are the major cell adhesion glycoproteins involved in cell-extracellular matrix (ECM) interaction and metastasis. Further, glycosylation on integrin is necessary for its proper folding and functionality. Herein, differential expression of integrins viz., αvß3 and αvß6 was examined in MDA-MB-231, MDA-MB-468 and MCF-10A cells, which signify three different stages of breast cancer development from highly metastatic to non-tumorigenic stage. The expression of αvß3 and αvß6 integrins at mRNA and protein levels was observed in all three cell lines and the results displayed a distinct pattern of expression. Highly metastatic cells showed enhanced expression of αvß3 than moderate metastatic and non-tumorigenic cells. The scenario was reversed in case of αvß6 integrin, which was strongly expressed in moderate metastatic and non-tumorigenic cells. N-glycosylation of αvß3 and αvß6 integrins is required for the attachment of cells to ECM proteins like fibronectin. The cell adhesion properties were found to be different in these cancer cells with respect to the type of integrins expressed. The results testify that αvß3 integrin in highly metastatic cells, αvß6 integrin in both moderate metastatic and non-tumorigenic cells play an important role in cell adhesion. The investigation typify that N-glycosylation on integrins is also necessary for cell-ECM interaction. Further, glycosylation inhibition by Swainsonine is found to be more detrimental to invasive property of moderate metastatic cells. Conclusively, types of integrins expressed as well as their N-glycosylation pattern alter during the course of breast cancer progression.

Silibinin combination with arsenic strongly inhibits survival and invasiveness of human prostate carcinoma cells.

Effects of silibinin, a naturally occurring flavanone, on prostate carcinoma (PCa) cells in presence of arsenic are not known. Arsenic is clinically approved for leukemia treatment; however, studies are not enough to support its role in the management of solid tumors. In the present study, we observed that silibinin (100 µM) modulated the oxidative status of human PCa DU145 cells exposed to arsenic (0.5 or 5 µM) and inhibited cell growth and survival by primarily inducing autophagy and apoptosis. The silibinin-arsenic combination also inhibited the growth, survival, and clonogenic potential of 22Rv1 PCa cells. Silibinin with 0.5 or 5 µM arsenic induced G1 or G2/M phase arrest, respectively, and decreased the protein levels of CDK2, -4, and -6 and cyclin D1, D3, and E and increased CDK inhibitors p21 and p27. Arsenic alone increased cyclin B1 level and Cdc2 kinase activity which were reduced in silibinin combination. Cell motility and invasiveness along with expression of MMP-2 and vimentin were suppressed. Together, these in vitro findings suggest that in presence of arsenic, silibinin strongly inhibits tumorigenic and metastatic potential of PCa cells.

Microgravity alters cancer growth and progression.

Study of the process of cancer initiation, growth and progression in altered gravity is of utmost importance considering the health status of researchers visiting in space and future scope of space tourism. Microgravity affects various cells in the body differently; however, the mechanisms of such effects are not understood completely. Therefore, it is imperative to explore various physiological and biochemical processes, particularly those which can influence the process of carcinogenesis. If the changes in physiological or biochemical processes do not revert back to normalcy even after returning from the space to earth, it may lead to various aberrations and morphological changes during the life span. Such changes could lead to pathological conditions including cancer. For example, microgravity is observed to suppress the activity of immune cells, which itself increases the risk of cancer development. It is little known how the microgravity affects cellular and molecular events that determine physiological and biological responses. There is also a possibility of changes in epigenetic signatures during microgravity exposure which remains unexplored. Herein, we have reviewed the effect of microgravity on relevant molecular and biological processes, and how it could influence the course of cancer development. In this regard, we have also highlighted the areas of research that require more attention to bridge the gap of understanding for such biological processes.

Sodium butyrate induces DRP1-mediated mitochondrial fusion and apoptosis in human colorectal cancer cells.

Sodium butyrate (NaBt) is the byproduct of anaerobic microbial fermentation inside the gastro-intestinal tract that could reach up to 20mM, and has been shown to inhibit the growth of various cancers. Herein, we evaluated its effect on mitochondrial fusion and associated induction of apoptosis in colorectal cancer cells (CRC). NaBt treatment at physiological (1-5mM) concentrations for 12 and 24h decreased the cell viability and induced G2-M phase cell cycle arrest in HCT116 (12h) and SW480 human CRC cells. This cell cycle arrest was associated with mitochondria-mediated apoptosis accompanied by a decrease in survivin and Bcl-2 expression, and generation of reactive oxygen species (ROS). Furthermore, NaBt treatment resulted in a significant decrease in the mitochondrial mass which is an indicator of mitochondrial fusion. Level of dynamin-related protein 1 (DRP1), a key regulator of mitochondrial fission and fusion where its up-regulation correlates with fission, was found to be decreased in CRC cells. Further, at early treatment time, DRP1 down-regulation was noticed in mitochondria which later became drastically reduced in both mitochondria as well as cytosol. DRP1 is activated by cyclin B1-CDK1 complex by its ser616 phosphorylation in which both cyclin B1-CDK1 complex and phospho-DRP1 (ser616) were strongly reduced by NaBt treatment. DRP1 was observed to be regulated by apoptosis as pan-caspase inhibitor showing rescue from NaBt-induced apoptosis also caused the reversal of DRP1 to the normal level as in control proliferating cells. Together, these findings suggest that NaBt can modulate mitochondrial fission and fusion by regulating the level of DRP1 and induce cell cycle arrest and apoptosis in human CRC cells.

ß-Sitosterol induces G1 arrest and causes depolarization of mitochondrial membrane potential in breast carcinoma MDA-MB-231 cells.

BACKGROUNDS: It is suggested that dietary phytosterols, such as ß-sitosterol (ST), have cancer chemopreventive effects; however, studies are limited to support such claims. Here, we evaluated the efficacy of ST on three different human cancer cell lines including skin epidermoid carcinoma A431 cells, lung epithelial carcinoma A549 cells and breast adenocarcinoma MDA-MB-231. METHODS: Cell growth assay, cell cycle analysis, FACS, JC-1 staining, annexin V staining and immunoblotting were used to study the efficacy of ST on cancer cells. RESULTS: ST (30-90 µM) treatments for 48 h and 72 h did not show any significant effect on cell growth and death in A431 cells. Whereas similar ST treatments moderately inhibited the growth of A549 cells by up to 13% (p ≤ 0.05) in 48 h and 14% (p ≤ 0.05-0.0001) in 72 h. In MDA-MB-231 cells, ST caused a significant dose-dependent cell growth inhibition by 31- 63% (p ≤ 0.0001) in 48 h and 40-50% (p ≤ 0.0001) in 72 h. While exploring the molecular changes associated with strong ST efficacy in breast cancer cells, we observed that ST induced cell cycle arrest as well as cell death. ST caused G0/G1 cell cycle arrest which was accompanied by a decrease in CDK4 and cyclin D1, and an increase in p21/Cip1and p27/Kip1 protein levels. Further, cell death effect of ST was associated with induction of apoptosis. ST also caused the depolarization of mitochondrial membrane potential and increased Bax/Bcl-2 protein ratio. CONCLUSIONS: These results suggest prominent in vitro anti-proliferative and pro-apoptotic effects of ST in MDA-MB-231 cells. This study provides valuable insight into the chemopreventive efficacy and associated molecular alterations of ST in breast cancer cells whereas it had only moderate efficacy on lung cancer cells and did not show any considerable effect on skin cancer cells. These findings would form the basis for further studies to understand the mechanisms and assess the potential utility of ST as a cancer chemopreventive agent against breast cancer.

Chemopreventive effect of Lagenaria siceraria in two stages DMBA plus croton oil induced skin papillomagenesis.

Cancer chemoprevention is a dietary or therapeutic strategy to prevent, suppress, or delay carcinogenesis either at initiation or progression level with nontoxic agents. Use of natural dietary compounds has been a major chemopreventive approach to modulate tumorigenic pathways. In the present study, we have evaluated Lagenaria siceraria (bottle gourd), a common vegetable of Indian household for its chemomodulatory potential. The fruit has been used in traditional medicine for a very long time for health benefits and to cure pain, ulcers, fever, cough, asthma, and other bronchial disorders. However, despite its reported beneficial effect the chemo modulatory potential of this plant has not been reported. Therefore chemopreventive effect of bottle gourd juice (BGJ) was studied against 7,12-dimethylbenz(a)anthracene (DMBA) plus croton oil induced skin papillomagenesis in Swiss albino mice. The effect was studied both at antiinitiation and antiinitiation/promotion level followed by histopathological study. A dose of 2.5% and 5% given in drinking water showed significant decrease in papilloma number, papilloma incidence, papilloma multiplicity, papilloma latency, papilloma volume, and papilloma size in different size range. Histopathological study showed chemopreventive effect by minimizing loss of stratification, a decrease in number of epithelial layers, reducing dermal infiltration and protection for various cytoplasmic changes. Higher dose of BGJ was found to be more effective than lower dose and the chemopreventive effect was maximum for antiinitiation/promotion treatment. Altogether, this study reports the chemopreventive effect of Lagenaria siceraria on skin papillomagenesis for the first time and suggests that its consumption may help in suppression of skin cancer.

Usnic acid inhibits growth and induces cell cycle arrest and apoptosis in human lung carcinoma A549 cells.

Usnic acid (UA) is a secondary metabolite abundantly found in lichens. Some studies have shown the anticancer potential of UA; however, its efficacy and associated mechanisms are yet to be fully explored. Herein, we assessed the anticancer potency and associated molecular alterations by UA in human lung carcinoma A549 cells. UA treatment (25-100 µM) for 24 and 48 h decreased total cell number by 39-67% (P < 0.01) and 68-89% (P < 0.001), respectively, and enhanced cell death by up to twofold and eightfold (P < 0.001), respectively. UA (1-10 µM) also significantly (P < 0.001) suppressed colony formation of A549 cells. The cell growth inhibition was associated with cell cycle arrest at G0/ G1 phase. UA decreased the expression of cyclin-dependent kinase (CDK)4, CDK6, and cyclin D1 and increased the expression of CDK inhibitor (CDKI) p21/cip1 protein. While examining the cell death associated molecular changes, we observed that UA induces mitochondrial membrane depolarization and led to more than twofold increase (P < 0.01) in apoptotic cells. The apoptotic effect of UA was accompanied by enhanced poly(ADP-ribose) polymerase cleavage. This study shows that UA inhibits cell growth involving G0/G1 phase cell cycle arrest and induces cell death via mitochondrial membrane depolarization and induction of apoptosis in human lung carcinoma cells.

Radio-modulatory effects of green tea catechin EGCG on pBR322 plasmid DNA and murine splenocytes against gamma-radiation induced damage.

Green tea is rich in polyphenols, like catechins, which are thought to contribute to the health benefits of tea. The aim of this study was to evaluate the radioprotective effect of EGCG (epigallocatechin-3-gallate), a green tea catechin on γ-radiation induced cell damage. Under acellular condition of radiation exposure, pBR322 plasmid DNA was protected by EGCG in a concentration dependent manner. Treatment of murine splenocytes with EGCG 2h prior to radiation (3Gy), protected the cellular DNA against radiation-induced strand breaks. EGCG also inhibited γ-radiation induced cell death in splenocytes. EGCG pretreatment to the cells decreased the radiation induced lipid peroxidation and membrane damage. The levels of phase II enzymes, glutathione and lactate dehydrogenase were restored with EGCG treatment prior to radiation. Our results show that pretreatment with EGCG offers protection to pBR322 DNA under acellular condition and normal splenocytes under cellular condition, against γ-radiation induced damage and is better radioprotector in comparison to quercetin and vitamin C.

Chemomodulatory effect of Dolichos biflorus Linn. on skin and forestomach papillomagenesis in Swiss albino mice.

Effect of consumption of three different doses (2%, 4% and 6%, w/w) of Dolichos biflorus Linn. seeds on hepatic drug metabolizing enzymes, antioxidant enzymes, reduced glutathione content, lactate dehydrogenase and lipid peroxidation in Swiss albino mice has been reported. Anti-carcinogenic effect has been studied by 7,12-dimethylbenzanthracene (DMBA)-induced skin and benzo(a)pyrene[B(a)P]-induced forestomach papillomagenesis models. D. biflorus consumption resulted in a significant increase in hepatic carcinogen metabolizing enzyme systems especially at 4% and 6% doses. Significant increase in reduced glutathione content (GSH) and specific activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and glutathione reductase (GR) in liver of mice, at 4% and 6% doses has been reported. Lactate dehydrogensae (LDH) activity and peroxidative damage has been significantly decreased at 4% and 6% doses. In skin papillomagenesis model, 4% and 6% dose in diet significantly reduced the tumor incidence (up to 25%), tumor multiplicity (up to 59%) and tumor volume per mouse (up to 70%) as compared to DMBA treated group. Importantly, significant reduction in tumor incidence (up to 33%) and tumor multiplicity (up to 61%) was evident for forestomach papillomagenesis model.

Chemomodulatory potential of Asparagus adscendens against murine skin and forestomach papillomagenesis.

We have evaluated the cancer chemopreventive efficacy of the roots of Asparagus adscendens, which have been used in the Indian traditional medicine system for a long time for the treatment of various ailments. For the first time, the effect of its different doses in a test diet was examined on 7,12-dimethylbenz(a)anthracene-induced skin and benzo(a)pyrene-induced forestomach papillomagenesis in mice. The effect of these test diets was also examined on drug-metabolizing phase I and phase II enzymes, antioxidant enzymes, reduced glutathione content, and peroxidative damage in mice. Results exhibited a significant reduction in the skin and the forestomach tumor incidence with respect to all the three (2, 4, and 6%, w/w) doses as compared with control. Among all the doses tested, 4% of test diet was most effective in protecting the animals against papillomagenesis. Further, the roots of A. adscendens inhibited phase I, and activated phase II system and antioxidant enzymes in the liver especially with 4% of test diet. The content of reduced glutathione was also significantly elevated whereas the peroxidative damage along with lactate dehydrogenase activity were reduced with all the three doses of the test diet. Together, these results suggest the cancer chemopreventive potential of A. adscendens, which could be mediated through drug-metabolizing phase I and phase II enzymes as well as free radical scavenging antioxidant enzymes.

Arsenic and its combinations in cancer therapeutics.

Arsenic is a metalloid that is considered to be a paradox in terms of its role both as a carcinogen and as a therapeutic agent. Chronic exposure to arsenic in drinking water has been linked with the development of various pathological conditions including cancer. Nevertheless, the therapeutic potential of arsenic and its derivatives in a variety of diseases have been exploited in the past. However, its role and mechanism of action as a therapeutic agent still remain an active area of research and investigation. Our ongoing work also suggests varied responses in cancer cells exposed to lower versus higher concentrations of arsenic. Furthermore, the arsenic combinations with chemopreventive or anticancer agents have been observed to sensitize the cell for cell-cycle arrest and cell death. Here, we have provided the account of recent updates on the mechanism of action of arsenic and its derivatives that lead to various disorders, and its role as a therapeutic agent both as a single agent as well as in combination chemotherapy.

Prevention of chemically induced mammary tumorigenesis by daidzein in pre-pubertal rats: the role of peroxidative damage and antioxidative enzymes.

Isoflavones are biologically active plant derived compounds that have several health promoting effects. In the present study hitherto unknown effects of one of the well known isoflavonoids, daidzein, has been evaluated on its chemo-preventive action against breast cancers in pre-pubertal rats. Either daidzein (500 mug/g bwt) or vehicle, dimethyl sulphoxide (DMSO), was administered at 16th, 18th, and 20th day post-partum and the chemopreventive efficacy was evaluated in dimethylbenz[a]nthracene (DMBA) induced Sprague-Dawley rats, at 50th day. To elucidate the mechanism of action, the antioxidative status was also examined in the liver and mammary gland of prebubertal rats using two different doses of daidzein (0.5 mg/kg bwt and 50 mg/kg bwt, p.o.) for 10 days. The specific activity of antioxidant enzymes as well as reduced glutathione (GSH) level and peroxidative damage were evaluated spectrophotometrically, both in liver as well as in mammary gland. Animals treated with daidzein pre-pubertally, showed a significant reduction in the tumorigenesis of mammary gland up to 37.4% as compared to animals induced for tumors with DMBA. In animals treated with 50 mg/kg of daidzein, a significant increase in the specific activities of the antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione transferase (GST), DT-diaphorase (DTD), and in GSH content were observed in both liver and mammary gland. Expectedly, the specific activity of lactate dehydrogenase (LDH) and level of peroxidative damage was decreased, as compared to that of control group of animals. Our results suggest that, daidzein can be considered as a potent chemopreventive agent against mammary carcinogenesis in pre-pubertal animals, with modulation of antioxidant enzymes being one of its mechanisms of actions.

Modulatory influence of prepubertal biochanin A exposure on mammary gland differentiation and expression of estrogen receptor-alpha and apoptotic proteins.

The modulatory influence of the phytoestrogen biochanin A, an isoflavinoid found in red clover (Trifolium pratense), on the differentiation and proliferation of mammary epithelial cells and the expression of estrogen receptor-alpha (ER-alpha) in female prepubertal Sprague-Dawley rat mammary glands was examined, for which there have been no reports to date. Biochanin A (500 microg/g bw) was injected subcutaneously on days 16, 18 and 20 post-partum. The mammary gland was dissected out and terminal end buds, terminal ducts and lobules were counted. ER-alpha, Bcl2, Bax and caspase-3 expression were determined by immunohistochemistry. Estradiol benzoate (EB) (500 ng/g bw) and dimethyl sulphoxide (DMSO) were used as the reference and vehicle, respectively. The results showed a significant enhancement of differentiation at post-natal day (PND) 21 as well as at PND 50 in the mammary glands. There was a significant decrease of ER-alpha expression at PND 21 and an increased expression of the same at PND 50, whereas increased proliferation at PND 21 and increased apoptosis at PND 50 in the mammary glands were observed in biochanin A treated animals. The mode and magnitude of the effect of biochanin A was almost similar to that of EB. These findings suggested that prepubertal exposure to biochanin A modulated the regulatory processes and in turn enhanced the differentiation and development of mammary glands in female rats. These observations may have significance in human health.

Protective effect of the cruciferous vegetable mustard leaf (Brassica campestris) against in vivo chromosomal damage and oxidative stress induced by gamma-radiation and genotoxic chemicals.

We evaluated the possible protective effect of the popular Indian cruciferous vegetable mustard leaf (Brassica campestris) against chromosomal damage and oxidative stress induced by gamma-radiation, cyclophosphamide (CPH) and urethane (URE), in mice. In vivo bone marrow micronucleus test was performed to assess chromosomal damage, and oxidative stress was monitored by estimating the changes in lipid peroxidation and the status of glutathione (GSH) as well as redox cycle antioxidants. Pretreatment with 50-250 mg/kg body wt of mustard leaf extract (MLE) for seven days significantly reduced the frequencies of micronuclei induced by gamma-radiation, CPH and URE. The protective effect against chromosomal damage was associated with modulation of lipid peroxidation as well as an increase in GSH and the GSH-dependent enzyme glutathione S-transferase (GST). Mass spectral analysis showed the presence of glucosinolates in MLE used for the pretreatment of mice. These findings indicate that intake of the green leafy cruciferous vegetable mustard leaf can lead to protection against in vivo genotoxicity and oxidative stress.

Eugenol as an in vivo radioprotective agent.

In the present work, an attempt has been made to evaluate the possible in vivo radioprotection by eugenol. Swiss albino mice were administered different doses of eugenol (75,150 and 300 mg/kg) before exposure to 1.5 Gy of gamma radiation. The micronucleus test was carried out to determine the genetic damage in bone marrow. Our results demonstrated significant reduction in the frequencies of micronucleated polychromatic erythrocytes (MnPCEs) with all three eugenol doses. Eugenol (150 mg/kg) was also tested against different doses of radiation (0.5, 1, 1.5, and 2 Gy) and was found to afford significant radioprotection. Reduction in the incidence of MnPCEs could be noticed up to 72 h postirradiation (1.5 Gy). Moreover, the level of peroxidative damage and the specific activities of lactate dehydrogenase (LDH) and methylglyoxalase I (Gly I) were observed in the liver of mice treated with eugenol for seven days in comparison to untreated mice. The results revealed that eugenol exerted significant protection against oxidative stress. This possibility was further supported by the enhanced response of Gly I and the lowered activity of LDH. The present findings suggested that eugenol has a radioprotective potential.

Extracellular calcium induces COX-2 in osteoblasts via a PKA pathway.

We have shown that extracellular calcium [Ca(+2)](e) induces cyclooxygenase-2 (COX-2) expression and prostaglandin E(2) (PGE(2)) production via an ERK signaling pathway in osteoblasts. In this study, we examined the roles of protein kinase C (PKC) and A (PKA) signaling pathways in the [Ca(+2)](e) induction of COX-2 in primary calvarial osteoblasts from mice transgenic for -371 bp of the COX-2 promoter fused to a luciferase reporter. Neither PKC specific inhibitors nor downregulation of the PKC pathway by phorbol myristate acetate (PMA) affected the [Ca(+2)](e) stimulation of COX-2 mRNA or promoter activity. In contrast, PKA inhibitors, used at doses that inhibited forskolin-stimulated luciferase activity by 90%, reduced [Ca(+2)](e)-stimulated COX-2 mRNA expression and promoter activity by 80-90%. [Ca(+2)](e) also stimulated a 2- to 3-fold increase in cAMP production. Hence, the [Ca(+2)](e) induction of COX-2 mRNA expression and promoter activity was independent of the PKC pathway and dependent on the PKA signaling pathway.

Alterations in antioxidant enzymes and oxidative damage in experimental diabetic rat tissues: effect of vanadate and fenugreek (Trigonellafoenum graecum).

With the premise that oxygen free radicals may be responsible for the severity and complications of diabetes, the level of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) as well as the oxidative damage were examined in the tissues of control, diabetic and treated rats. After 3 weeks of diabetes, the activity of CAT was significantly increased in heart in diabetes (about 6-fold) but decreased in liver. The SOD activity decreased significantly in liver but increased in brain. The activity of GPx decreased significantly in liver and increased in kidney. A significant increase was observed in oxidative damage in heart and kidney and a small increase in brain with decrease in liver and muscle. Vanadate and fenugreek (Trigonella foenum graecum) administration to diabetic animals showed a reversal of the disturbed antioxidant levels and peroxidative damage. Results suggest that oxidative stress play a key role in the complications of diabetes. Vanadate and fenugreek seeds showed an encouraging antioxidant property and can be valuable candidates in the treatment of the reversal of the complications of diabetes.

Antioxidant and non-toxic properties of Piper betle leaf extract: in vitro and in vivo studies.

Piper betle leaves are used in folk medicine for the treatment of various disorders and is commonly chewed among Asians. The present study investigates the protective efficacy of P. betle leaf extract. The presence of the extract inhibited the radiation induced lipid peroxidation process effectively. This could be attributed to its ability to scavenge free radicals involved in initiation and propagation steps. Oral supplementation with extract (1, 5 and 10 mg/kg) was administered daily for 2 weeks to Swiss albino mice and the hepatic antioxidant status was analysed. The GSH content was enhanced and no appreciable change was found in the levels of oxidative damage in terms of lipid peroxidation. Also, the specific activity of SOD increased in a dose dependent manner. These factors indicate the elevation of antioxidant status in the animals. The effect on the glyoxalase system which is considered to be activated under stress conditions was also investigated. Our findings did not observe any significant change in gly I and gly II activities, implying a non-stress condition after oral treatment of the extract. The present study indicates the antioxidant activity of P. betle leaf extract and its potential to elevate the antioxidant status.

Salt- and glyphosate-induced increase in glyoxalase I activity in cell lines of groundnut (Arachis hypogaea).

Glyoxalase I (EC 4.4.1.5) activity has long been associated with rapid cell proliferation, but experimental evidence is forthcoming, linking its role to stress tolerance as well. Proliferative callus cultures of groundnut (Arachis hypogaea L. cv. JL24) showed a 3.3-fold increase in glyoxalase I activity during the logarithmic growth phase, correlating well with the data on FW gain and mitotic index. Inhibition of cell division decreased glyoxalase I activity and vice versa, thus further corroborating its role as a cell division marker enzyme. Cell lines of A. hypogaea selected in the presence of high salt (NaCl) and herbicide (glyphosate) concentrations, yielded 4.2- to 4.5-fold and 3.9- to 4.6-fold elevated glyoxalase I activity, respectively, in a dose dependent manner reflective of the level of stress tolerance. The stress-induced increase in enzyme activity was also accompanied by an increase in the glutathione content. Exogenous supplementation of glutathione could partially alleviate the growth inhibition of callus cultures induced by methylglyoxal and d-isoascorbic acid, but failed to recover the loss in glyoxalase I activity due to d-isoascorbic acid. The adaptive significance of elevated glyoxalase I activity in maintaining glutathione homeostasis has been discussed in view of our understanding on the role of glutathione in the integration of cellular processes with plant growth and development under stress conditions.