Jagneshwar Dandapat

Dietary vitamin-E modulates antioxidant defence system in giant freshwater prawn, Macrobrachium rosenbergii

The objectives of the present study were to determine the effect of supplementary vitamin-E (200, 400 and 600 mg/kg feed) on lipid peroxidation (LPX) and antioxidant defence system in gills and hepatopancreas of the freshwater prawn, Macrobrachium rosenbergii. Results indicated that vitamin-E inhibited LPX in the hepatopancreas in a comparatively lower dose than gills. Superoxide dismutase (SOD) activity was decreased significantly in gills in response to all the three supplemented diet, but in hepatopancreas decrease was observed only in response to higher doses of vitamin-E (400 and 600 mg/kg feed). Catalase (CAT) activity was reduced significantly only in gills but not in hepatopancreas. While glutathione peroxidase (GPX) activity was significantly elevated in the hepatopancreas by vitamin-E, its activity remains unaltered in gills. On the contrary, glutathione reductase (GR) activity was decreased in gills but that of hepatopancreas was constant. Glutathione (GSH) content of both gills and hepatopancreas was substantially elevated in the vitamin-E supplemented prawns. Although the ascorbic acid (ASA) content of gills was unchanged by vitamin-E, its level elevated significantly in hepatopancreas. Thus the findings of the present investigation suggest that dietary vitamin-E is capable of reducing LPX level and can modulate antioxidant defence system in gills and hepatopancreas, nevertheless, the response is highly tissue specific. It is further observed that highest dose of vitamin-E (600 mg/kg feed) could not render much additional protection in both the tissues.

Lipid peroxidation and antioxidant defence status during larval development and metamorphosis of giant prawn, Macrobrachium rosenbergii

In the present communication we studied the involvement of reactive oxygen species and alteration in antioxidant defence status during larval development and metamorphosis of giant prawn, Macrobrachium rosenbergii. Overall results indicate that there was a decline in endogenous lipid peroxidation level during larval development. Activity of superoxide dismutase was the lowest in early larval stages (Zoea-I and II) and thereafter increased in V and VI stages, followed by a decrease in the subsequent larval stages. Catalase and glutathione peroxidase did not exhibit specific pattern of changes during development. Reduced glutathione content exhibited an incremental increase during larval progression until metamorphosis. Ascorbic acid content of the larval tissue remained unaltered during development but a sharp fall was marked in its content in the post-larvae. Hence it is concluded that early larvae face high oxidative stress as evident from the high content of thiobarbituric acid reactive substances. This may be due to direct exposure of larvae to ambient oxygen of the water as well as their low antioxidant potential. However, during development with the augmentation in antioxidant reserve of the larval tissues a diminution in the oxidative stress was recorded. Thus it is presumed that antioxidant defences play an important role in providing protection to the developing larvae from oxidative assault during larval progression and metamorphosis.

Curcumin and Ellagic acid synergistically induce ROS generation, DNA damage, p53 accumulation and apoptosis in HeLa cervical carcinoma cells.

Cervical cancer and precancerous lesions of the cervix continue to be a global health issue, and the medication for the treatment for chronic HPV infection so far has not been effective. Potential anticancer and anti HPV activities of two known phytochemicals, Curcumin and Ellagic acid were evaluated in HeLa cervical cancer cells. Curcumin is a natural compound found in the root of Curcuma longa plant and Ellagic acid a polyphenol found in fruits of strawberries, raspberries and walnuts. The combination of Curcumin and Ellagic acid at various concentrations showed better anticancer properties than either of the drug when used alone as evidenced by MTT assay. Besides this, Curcumin and Ellagic acid also restore p53, induce ROS formation and DNA damage. Mechanistic study further indicated that Curcumin and Ellagic acid show anti-HPV activity as evidenced by decrease in the HPV E6 oncoprotein on HeLa cells.

Induction of oxidative stress and inhibition of superoxide dismutase expression in rat cerebral cortex and cerebellum by PTU-induced hypothyroidism and its reversal by curcumin

The present study was carried out to elucidate the effectiveness of curcumin in ameliorating the expression of superoxide dismutase (SOD) in cerebral cortex and cerebellum of rat brain under 6-propyl-2-thiouracil (PTU)-induced hypothyroidism. Induction of hypothyroidism in adult rats by PTU resulted in augmentation of lipid peroxidation (LPx), an index of oxidative stress in cerebellum but not in cerebral cortex. Curcumin-supplementation to PTU-treated (hypothyroid) rats showed significant reduction in the level of LPx in both the regions of brain. The decreased translated products (SOD1 and SOD2) and the unchanged activity of SOD in cerebral cortex of PTU-treated rats were increased on supplementation of curcumin to the hypothyroid rats. Declined translated products of SOD1 and SOD2 in cerebellum of PTU-treated rats were alleviated on administration of curcumin to hypothyroid rats. On the other hand, the decreased activity of SOD in cerebellum of PTU-treated rats was further declined on administration of curcumin to the hypothyroid rats. Results of the present investigation indicate that curcumin differentially modulates the expression of superoxide dismutase in rat brain cortex and cerebellum under PTU-induced hypothyroidism.

Hypothyroidism modulates renal antioxidant gene expression during postnatal development and maturation in rat.

In the present study effects of 6-n-propyl thiouracil (PTU)-induced hypothyroidism on renal antioxidant defence system during postnatal development (from birth to 7, 15 and 30days old) and on adult rats were reported. Hypothyroidism in rats was induced by feeding the lactating mothers (from the day of parturition till weaning, 25days old) or directly to the pups with 0.05% PTU in drinking water. The activities of Cu/Zn-superoxide dismutase (SOD1) and glutathione peroxidase (GPx) were increased in 30days old hypothyroid rats with respect to their respective controls, on the other hand, levels of translated products and activities of Mn-superoxide dismutase (SOD2) and catalase (CAT) were decreased in hypothyroid rats of all age groups as compared to their respective control rats. SOD1 activity remained unchanged in persistent (PTU-treatment from birth to 90days old) hypothyroid rats as compared to euthyroid. However, a decreased activity of SOD1 was recorded in transient (PTU-treatment from birth to 30days then withdrawal till 90days old) hypothyroid rats with respect to control rats. The mRNA level, protein expression and activity of SOD2 and CAT were significantly decreased in persistent hypothyroid rats as compared to euthyroid rats. The activity of GPx was significantly increased in both persistent and transient hypothyroid rats with respect to euthyroid rats. The present study indicates modulation of antioxidant defence status of rat kidney during postnatal development and maturation by hypothyroidism.

Expression of antioxidant genes in renal cortex of PTU-induced hypothyroid rats: effect of vitamin E and curcumin

The present study was undertaken to investigate the effect of vitamin E and curcumin on the expression of antioxidant genes in 6-propyl-2-thiouracil (PTU)-induced hypothyroid rat renal cortex. The levels of lipid peroxidation and protein carbonylation were increased in hypothyroid rat kidney. Co-administration of vitamin E and curcumin to hypothyroid rats resulted in amelioration of lipid peroxidation level, whereas curcumin alone alleviated the protein carbonylation level. The mRNA levels of SOD1 and SOD2 were decreased in hypothyroid rats. Decreased level of SOD1 transcripts was observed in hypothyroid rats supplemented with curcumin alone or co-administrated with vitamin E. Translated products of SOD1 and SOD2 in hypothyroid rats was elevated in response to supplementation of both the antioxidants. Decreased SOD1 and SOD2 activities in hypothyroid rats compared to control were either unaltered or further decreased in response to the antioxidants. Expressions of CAT at transcript and translate level along with its activity were down regulated in hypothyroid rats. Administration of vitamin E to hypothyroid rats resulted in elevated CAT mRNA level. In contrast, expression of CAT protein was elevated in response to both the antioxidants. However, CAT activity was unaltered in response to vitamin E and curcumin. GPx1 and GR mRNA level and the activity of glutathione peroxidase (GPx) were not affected in response to induced hypothyroidism. The activity of GPx was increased in response to vitamin E treatment, whereas decreased GR activity in hypothyroid rats was further declined by the administration of antioxidants. The over all results suggest that vitamin E and curcumin differentially modulate the altered antioxidant defence mechanism of rat kidney cortex under experimental hypothyroidism.

Curcumin differentially regulates the expression of superoxide dismutase in cerebral cortex and cerebellum of l-thyroxine (T4)-induced hyperthyroid rat brain

The present investigation was aimed to elucidate the effect of curcumin on lipid peroxidation (LPx) and superoxide dismutase (SOD) in l-thyroxine (T4)-induced oxidative stress in cerebral cortex and cerebellum of rat brain. Elevated level of LPx in cerebral cortex declined to control level on supplementation of curcumin to T4-treated rats. On the other hand, unaltered LPx level in T4-treated rats showed a significantly decreased level of LPx on supplementation of curcumin. The increased activity of SOD and translated products of SOD1 and SOD2 in cerebral cortex of T4-treated rats was ameliorated on supplementation of curcumin. The decreased activity of SOD and protein expression of SOD1 in cerebellum of T4-treated rats were ameliorated on administration of curcumin. On the other hand, SOD2 expression was not influenced either by T4-treated or by curcumin supplementation to T4-treated rats. Results of the present investigation reveal that the regulation of expression of SOD by curcumin in different regions (cerebral cortex and cerebellum) of rat brain is different under hyperthyroidism.

Effect of heavy metals on growth response and antioxidant defense protection in Bacillus cereus

Bacterial cells in aerobic environment generate reactive oxygen species which may lead to oxidative stress, induced by a wide range of environmental factors including heavy metals. In the present context an attempt has been made to determine the toxic impact of cadmium and copper on growth performance, oxidative stress, and relative level of antioxidant protection in Bacillus cereus. Outcome of this study suggests that both the metal ions depleted the growth rate in this organism with respect to time and concentration of the metal ions. CdCl2 exposure induced extracellular glutathione (GSH) production, whereas, its level was declined in response to CuSO4. Superoxide dismutase (SOD) activity and hydrogen peroxide (H2O2) content was elevated under CdCl2 stress but the activity of catalase (CAT) was inhibited. In contrast, incubation of bacteria with CuSO4 exhibited decreased SOD activity with concomitant rise in CAT activity and H2O2 content. We also observed elevation of intracellular GSH level in this bacteria following supplementation of N‐acetyl cysteine (NAC) in the medium. Overall findings of this study indicated differential toxicity of CdCl2 and CuSO4 in inducing oxidative stress, depleting growth rate and the possible involvement of GSH and CAT in adaptive antioxidant response.

Effect of aminotriazole on antioxidant defense system of tasar silkworm Antheraea mylitta

This study was designed to find out the metabolic consequences of H2O2 following catalase inhibition by aminotriazole in the fat body of an Antheraea mylitta pupa. H2O2 content in the pupal fat body exhibited a decreasing trend over the experimental period (up to 48 h). However, a substantial decrease in its level was marked after 12, 24 and 48 h of treatment. The level of lipid peroxidation was elevated within 4 h of aminotriazole injection. Nevertheless, its level significantly decreased after 12, 24 and 48 h of treatment. Superoxide dismutase activity was elevated within 4 h, followed by a transient decrease in its activity at 12 h of treatment and again increased over the experimental period. Catalase activity was found to decline in the fat body within 4 h of aminotriazole treatment compared to the control. However, it was surprising to observe that there was a two‐fold increase in catalase activity compared to its previous experimental group after 12 h, followed by a rapid decline in its activity at 24 h of aminotriazole injection and non‐detectable catalase activity at 48 h. Ascorbic acid content was found to be elevated after 12 h of injection and maintained an increasing trend over the rest of the experimental period compared to the respective control. Despite the progressive inhibition of catalase activity beyond 12 h of treatment, H2O2 accumulation was not observed as a consequence of catalase inhibition. Hence, catalase depletion by aminotriazole involves compensatory changes in other components of the antioxidant system for the efficient removal of H2O2.

Pro-oxidative challenges and antioxidant protection during larval development of non-mulberry silkworm, Antheraea mylitta (Lepidoptera: Saturniidae)

Abstract The non-mulberry silkworm, Antheraea mylitta Drury, 1773, is important for the silk industry. Its larvae are phytophagous and pass through five stages (1st–5th instar) during larval development. Cellular events during their development contribute to increased levels of pro-oxidants. Antioxidant defences are, therefore, of critical importance in minimising oxidative damage. Thus, in the present study, stage-specific oxidative challenges and relative levels of antioxidant defences have been assessed during the larval development of A. mylitta. The overall results indicate a progressive decrease in oxidative threat during larval ontogeny. Comparatively high activity of superoxide dismutase (SOD) and catalase (CAT) observed in the 1st instar larvae indicates an adaptive antioxidant response, which could attenuate the elevated oxidative challenges. CAT activity remained unaltered in the midgut during transformation of the larvae from 4th–5th instar, and it was below detection level in serum. Glutathione S-transferase (GST) activity did not exhibit a specific trend; however, it showed tissue specificity in advanced larvae. Glutathione (GSH) content was progressively enhanced during development and exhibited a compensatory function with ascorbic acid (ASA), thus substantiating the role of a GSH–ASA redox couple. Findings of the study imply that early larvae (1st–3rd instar) encounter considerable degrees of pro-oxidative assault and get protection from enzymatic antioxidants. In contrast, advanced larvae receive combined protection from enzymatic and nonenzymatic antioxidants. Therefore, it is assumed that oxidative stress during larval development of A. mylitta is stage-specific and, accordingly, the antioxidant defences are strategic in providing protection to the developing larvae.