Aftab Alam - Academia.edu (original) (raw)
Papers by Aftab Alam
Journal of Geophysical Research, 2003
1] Measurements are reported of particle number concentration at two urban sites within Birmingha... more 1] Measurements are reported of particle number concentration at two urban sites within Birmingham, UK. The measurements were made with a condensation particle counter (TSI Model 3022A) and an ultrafine particle counter (TSI Model 3025) operated in tandem. Other colocated measurements included particle surface area by epiphaniometer, sulfur dioxide, oxides of nitrogen and ozone, solar radiation or J O 1 D , and in some campaigns, particle number size distribution by Scanning Mobility Particle Sizer. Events were identified when substantial excursions in particle number count were accompanied by a divergence between the two particle counters indicating a large number of particles in the 3-7 nm diameter range. Criteria have been developed to distinguish between particles within this size range arising from homogeneous nucleation within the atmosphere and from emissions from point sources. Out of a total of 232 days sampling distributed throughout the year, events on only 8 days could be attributed fairly unequivocally to homogeneous nucleation processes, with a further 4 days possibly attributable. Nucleation events occur in winter as well as summer months, but depend, among other things, upon a low particle surface area. Modeling of aerosol dynamical processes for 20 June 1999, indicates that the observations can be explained by a nucleation rate of 6 Â 10 6 cm À3 s À1 at a condensable vapor concentration (as H 2 SO 4 ) of 6.5 Â 10 7 cm À3 . It is inferred that both the nucleation and particle growth processes involve condensable molecules other than, or in addition to, sulfuric acid.
Journal of Geophysical Research, 2003
1] Measurements are reported of particle number concentration at two urban sites within Birmingha... more 1] Measurements are reported of particle number concentration at two urban sites within Birmingham, UK. The measurements were made with a condensation particle counter (TSI Model 3022A) and an ultrafine particle counter (TSI Model 3025) operated in tandem. Other colocated measurements included particle surface area by epiphaniometer, sulfur dioxide, oxides of nitrogen and ozone, solar radiation or J O 1 D , and in some campaigns, particle number size distribution by Scanning Mobility Particle Sizer. Events were identified when substantial excursions in particle number count were accompanied by a divergence between the two particle counters indicating a large number of particles in the 3-7 nm diameter range. Criteria have been developed to distinguish between particles within this size range arising from homogeneous nucleation within the atmosphere and from emissions from point sources. Out of a total of 232 days sampling distributed throughout the year, events on only 8 days could be attributed fairly unequivocally to homogeneous nucleation processes, with a further 4 days possibly attributable. Nucleation events occur in winter as well as summer months, but depend, among other things, upon a low particle surface area. Modeling of aerosol dynamical processes for 20 June 1999, indicates that the observations can be explained by a nucleation rate of 6 Â 10 6 cm À3 s À1 at a condensable vapor concentration (as H 2 SO 4 ) of 6.5 Â 10 7 cm À3 . It is inferred that both the nucleation and particle growth processes involve condensable molecules other than, or in addition to, sulfuric acid.
International Journal of Cancer, 1983
Conditions are described for the development of methotrexate resistance in CCRF/CEM human lymphoi... more Conditions are described for the development of methotrexate resistance in CCRF/CEM human lymphoid cells and an attempt is made to distinguish between those conditions that lead to methotrexate resistance through impairment of cellular transport of methotrexate and those that lead to resistance through enhanced production of dihydrofolate reductase. A restistant line showing a 200-fold enhancement of dihydrofolate reductase has been obtained. The CCRF/CEM human cells are much more sensitive to methotrexate than are murine cells.
Aquacultural Engineering, 2003
Three kinds of locally available plastic biofilter media with different configurations (plastic r... more Three kinds of locally available plastic biofilter media with different configurations (plastic rolls, PVC pipes and scrub pads) were evaluated for their efficiency in organic waste removal from the effluents of an intensive recirculating tilapia culture system. A set of three types of ...
Journal of Ethnopharmacology, 2003
Hemidesmus indicus has been shown to possess significant activity against immunotoxicity and othe... more Hemidesmus indicus has been shown to possess significant activity against immunotoxicity and other pharmacological and physiological disorders. In this communication, we have shown the modulating effect of H. indicus on cumene hydroperoxide-mediated cutaneous oxidative stress and tumor promotion response in murine skin. Cumene hydroperoxide treatment (30 mg per animal) increased cutaneous microsomal lipid peroxidation and induction of xanthine oxidase activity which are accompanied by decrease in the activities of cutaneous antioxidant enzymes and depletion in the level of glutathione. Parallel to these changes a sharp decrease in the activities of phase II metabolizing enzymes was observed. Cumene hydroperoxide treatment also induced the ornithine decarboxylase activity and enhanced the [ 3 H]-thymidine uptake in DNA synthesis in murine skin. Application of ethanolic extract of H. indicus at a dose level of 1.5 and 3.0 mg/kg body weight in acetone prior to that of cumene hydroperoxide treatment resulted in significant inhibition of cumene hydroperoxide-induced cutaneous oxidative stress, epidermal ornithine decarboxylase activity and enhanced DNA synthesis in a dose-dependent manner. Enhanced susceptibility of cutaneous microsomal membrane for lipid peroxidation and xanthine oxidase activity were significantly reduced (P < 0.01). In addition the depleted level of glutathione, inhibited activities of antioxidants and phase II metabolizing enzymes were recovered to significant level (P < 0.05). In summary, our data suggest that H. indicus is an effective chemopreventive agent in skin and capable of ameliorating hydroperoxide-induced cutaneous oxidative stress and tumor promotion.
Pharmacology & Toxicology, 2001
In an earlier communication, we have shown that Tephrosia purpurea ameliorates benzoyl peroxide-i... more In an earlier communication, we have shown that Tephrosia purpurea ameliorates benzoyl peroxide-induced oxidative stress in murine skin . The present study was designed to investigate a chemopreventive efficacy of T. purpurea against N-diethylnitrosamine-initiated and potassium bromate-mediated oxidative stress and toxicity in rat kidney. A single intraperitoneal dose of N-diethylnitrosamine (200 mg/kg body weight) one hr prior to the dose of KBrO 3 (125 mg/kg body weight) increases microsomal lipid peroxidation and the activity of xanthine oxidase and decreases the activities of renal antioxidant enzymes viz., catalase, glutathione peroxidase, glutathione reductase and glucose-6-phosphate dehydrogenase, phase II metabolizing enzymes such as glutathione-S-transferase and quinone reductase and causes depletion in the level of renal glutathione content. A sharp increase in blood urea nitrogen and serum creatinine has also been observed. Prophylactic treatment of rats with T. purpurea at doses of 5 mg/kg body weight and 10 mg/kg body weight prevented N-diethylnitrosamine-initiated and KBrO 3 promoted renal oxidative stress and toxicity. The susceptibility of renal microsomal membrane for iron ascorbate-induced lipid peroxidation and xanthine oxidase activities were significantly reduced (PϽ0.01). The depleted levels of glutathione, the inhibited activities of antioxidant enzymes, phase II metabolizing enzymes and the enhanced levels of serum creatinine and blood urea nitrogen were recovered to a significant level (PϽ0.01). All the antioxidant enzymes were recovered dose-dependently. Our data indicate that T. purpurea besides a skin antioxidant can be a potent chemopreventive agent against renal oxidative stress and carcinogenesis induced by N-diethylnitrosamine and KBrO 3 .
Pharmacy and Pharmacology Communications, 1999
The modulatory effect of Tephrosia purpurea on benzoyl peroxide-induced cutaneous oxidative stres... more The modulatory effect of Tephrosia purpurea on benzoyl peroxide-induced cutaneous oxidative stress is described. Benzoyl peroxide is an effective cutaneous tumour promoter acting through the generation of oxidative stress. Benzoyl peroxide treatment increases cutaneous microsomal lipid peroxidation and hydrogen peroxide generation. The activity of cutaneous antioxidant enzymes, catalase glutathione peroxidase, glutathione reductase and glutathione S-transferase is decreased and the levels of cutaneous glutathione are depleted.
Life Sciences, 2001
Ferula (a genus of many species) commonly known as asafoetida is used as a flavoring agent in foo... more Ferula (a genus of many species) commonly known as asafoetida is used as a flavoring agent in food and is used as a traditional medicine for many diseases in many parts of world. In the current investigation, we report the antioxidant and anticarcinogenic potential of asafoetida ( Ferula narthex ) in swiss albino mice. A single dose of TPA (20nmol/0.2 ml acetone /animal), a known tumor promoter decreased the cellular antioxidant level significantly (p Ͻ 0.01) when applied topically to mice skin. It also induced the ODC activity, rate of DNA synthesis, hydrogen peroxide level, xanthine oxidase activity and protein carbonyl content in mice skin significantly (p Ͻ 0.01). These events are early biomarkers of carcinogenesis. However, the pretreatment of animals with asafoetida (300, 400 and 500 g/200 l acetone / animal) caused the reversal of all events significantly (p Ͻ 0.01). The pretreament of animals with asafoetida recovered the antioxidant level and reversed the induced ODC activity and DNA synthesis significantly (p Ͻ 0.01). We conclude that asafoetida is a potent antioxidant and can afford protection against free radical mediated diseases such as carcinogenesis.
Journal of Ethnopharmacology, 2000
The hepatoprotective activity of the 50% ethanol extract of the bark of Lawsonia alba syn. L. ine... more The hepatoprotective activity of the 50% ethanol extract of the bark of Lawsonia alba syn. L. inermis was investigated against the carbon tetrachloride-induced oxidative stress. Pretreatment of rats with doses of 250 and 500 mg/kg of the plant extract significantly (PB 0.001) lowered serum transaminases (GOT and GPT) and LDH levels, respectively, in a dose dependent manner against the significant (P B0.001) rise of these damage marker enzymes when challenged with CCl 4 (1 ml/kg, orally). Parallel to these changes, the plant extract prevented CCl 4 -induced oxidative stress by significantly maintaining the levels of reduced glutathione (GSH), its metabolizing enzymes and simultaneously inhibiting the production of free radicals. Pretreatment of rats with the extract also inhibited the peroxidation of microsomal lipids in a dose-dependent manner.
Pharmacological Research, 2001
The modulating effect of Lupeol [lup-20(29)-en-3 beta -ol], a triterpene found in many fruits and... more The modulating effect of Lupeol [lup-20(29)-en-3 beta -ol], a triterpene found in many fruits and medicinal plants, on benzoyl peroxide-induced tumor promotion responses or tumor promotion in murine skin is described. Benzoyl peroxide is an effective cutaneous tumor promoter acting through the generation of oxidative stress, the induction of ornithine decarboxylase activity and the enhancement of DNA synthesis. Benzoyl peroxide treatment increases cutaneous microsomal lipid peroxidation and hydrogen peroxide generation. The activity of the cutaneous antioxidant enzymes, namely catalase, glutathione peroxidase, glutathione reductase and glutathione S-transferase, is decreased and levels of cutaneous glutathione are depleted. Benzoyl peroxide treatment also induces ornithine decarboxylase activity and enhances [3H]thymidine uptake in DNA synthesis. Prophylactic treatment of mice with lupeol (0.75 and 1.5 mg per animal) 1 hour before benzoyl peroxide treatment resulted in a diminution of benzoyl peroxide-mediated damage. The susceptibility of cutaneous microsomal membrane to lipid peroxidation and hydrogen peroxide generation was significantly reduced (P&amp;lt; 0.01 and P&amp;lt; 0.01, respectively). In addition, depleted levels of glutathione and inhibited activity of antioxidant enzymes were recovered to a significant level (P&amp;lt; 0.01, P&amp;lt; 0.05 and P&amp;lt; 0.01, respectively). Similarly, the elevated ornithine decarboxylase activity and enhanced thymidine uptake in DNA synthesis were inhibited significantly (P&amp;lt; 0.05) in a dose-dependent manner. The protective effect of lupeol was dose dependent in all parameters. The results suggest that lupeol is an effective skin chemopreventive agent that may suppress benzoyl peroxide-induced cutaneous toxicity.
Pharmacological Research, 2001
In recent years, considerable emphasis has been placed on identifying new cancer chemopreventive ... more In recent years, considerable emphasis has been placed on identifying new cancer chemopreventive agents, which could be useful for the human population. Tephrosia purpurea has been shown to possess significant activity against hepatotoxicity, pharmacological and physiological disorders. Earlier we showed that Tephrosia purpurea inhibits benzoyl peroxide-mediated cutaneous oxidative stress and toxicity. In the present study, we therefore assessed the effect of Tephrosia purpurea on 12-O-tetradecanoyl phorbal-13-acetate (TPA; a well-known phorbol ester) induced cutaneous oxidative stress and toxicity in murine skin. The pre-treatment of Swiss albino mice with Tephrosia purpurea prior to application of croton oil (phorbol ester) resulted in a dose-dependent inhibition of cutaneous carcinogenesis. Skin tumor initiation was achieved by a single topical application of 7,12-dimethyl benz(a)anthracene (DMBA) (25 microg per animal per 0.2 ml acetone) to mice. Ten days later tumor promotion was started by twice weekly topical application of croton oil (0.5% per animal per 0.2 ml acetone, v /v). Topical application of Tephrosia purpurea 1 h prior to each application of croton oil (phorbol ester) resulted in a significant protection against cutaneous carcinogenesis in a dose-dependent manner. The animals pre-treated with Tephrosia purpurea showed a decrease in both tumor incidence and tumor yield as compared to the croton oil (phorbol ester)-treated control group. In addition, a significant reduction in TPA-mediated induction in cutaneous ornithine decarboxylase (ODC) activity and [3H]thymidine incorporation was also observed in animals pre-treated with a topical application of Tephrosia purpurea. The effect of topical application of Tephrosia purpurea on TPA-mediated depletion in the level of enzymatic and non-enzymatic molecules in skin was also evaluated and it was observed that topical application of Tephrosia purpurea prior to TPA resulted in the significant recovery of TPA-mediated depletion in the level of these molecules, namely glutathione, glutathione S-transferase, glutathione reductase and catalase. From these data we suggest that Tephrosia purpurea can abrogate the tumor-promoting effect of croton oil (phorbol ester) in murine skin.
Pharmacological Research, 2002
Vitis vinifera (grapes) is used as a fruit worldwide and known for its pharmacological properties... more Vitis vinifera (grapes) is used as a fruit worldwide and known for its pharmacological properties. The present paper assesses the chemopreventive potential of Vitis vinifera against 12-O-tetradecanoyl-13phorbol acetate (TPA)-mediated tumor promotion in 7,12-dimethyl-benz[a]anthracene (DMBA) initiated mice skin. Skin tumor initiation was achieved by a single topical application of DMBA (40 µg/animal/0.20 ml acetone) to mice. Two weeks after the initiation, promoting agent, TPA (5.0 µg/animal/0.2 ml acetone) was applied two times a week for 20 weeks. Pretreatment of Vitis vinifera 1 h prior to each application of TPA resulted in protection against cutaneous tumorigenesis in dose-dependent manner. This inhibition was evident when tumor data was considered as the percentage of mice with tumor and the number of tumors per mouse. We have shown that typical application of Vitis vinifera prior to that of TPA resulted in significant inhibition against TPA-caused induction of epidermal ODC activity (P < 0.001) and DNA synthesis. Application of Vitis vinifera at a dose level of 5.0 mg and 10.0 mg kg −1 body weight in acetone prior to that of TPA treatment resulted in partial significant inhibition of oxidative stress in dose-dependent manner. The concomitant increase in the microsomal lipid peroxidation and xanthine oxidase activities were significantly reduced (P < 0.001). In addition, the depleted level of glutathione and inhibited activities of antioxidant enzymes were recovered to the partial significant level. Hence, it can be suggested that Vitis vinifera can be used as a chemopreventive agent against oxidative stress and carcinogenesis.
Pharmacology & Toxicology, 2000
In recent years, considerable efforts have been made to identify new chemopreventive agents which... more In recent years, considerable efforts have been made to identify new chemopreventive agents which could be useful for man. Myrica nagi, a subtropical shrub, has been shown to possess significant activity against hepatotoxicity and other pharmacological and physiological disorders. We have shown a chemopreventive effect of Myrica nagi on cumene hydroperoxide-induced cutaneous oxidative stress and toxicity in mice. Cumene hydroperoxide treatment at a dose level of 30 mg/animal/0.2 ml acetone enhances susceptibility of cutaneous microsomal membrane for iron-ascorbateinduced lipid peroxidation and induction of xanthine oxidase activity which are accompanied by decrease in the activities of cutaneous antioxidant enzymes such as catalase, glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase and depletion in the level of cutaneous glutathione. Parallel to these changes a sharp decrease in the activities of phase II metabolizing enzymes such as glutathione S-transferase and quinone reductase has been observed. Application of Myrica nagi at doses of 2.0 mg and 4.0 mg/kg body weight in acetone prior to that of cumene hydroperoxide (30 mg/animal/0.2 ml acetone) treatment resulted in significant inhibition of cumene hydroperoxide-induced cutaneous oxidative stress and toxicity in a dose-dependent manner. Enhanced susceptibility of cutaneous microsomal membrane for lipid peroxidation induced by iron ascorbate and xanthine oxidase activities were significantly reduced (P∞0.05). In addition the depleted level of glutathione, the inhibited activities of antioxidants, and phase II metabolizing enzymes were recovered to a significant level (P∞0.05). The protective effect of Myrica nagi was dose-dependent. In summary our data suggest that Myrica nagi is an effective chemopreventive agent in skin and capable of ameliorating cumene hydroperoxideinduced cutaneous oxidative stress and toxicity.
Journal of Geophysical Research, 2003
1] Measurements are reported of particle number concentration at two urban sites within Birmingha... more 1] Measurements are reported of particle number concentration at two urban sites within Birmingham, UK. The measurements were made with a condensation particle counter (TSI Model 3022A) and an ultrafine particle counter (TSI Model 3025) operated in tandem. Other colocated measurements included particle surface area by epiphaniometer, sulfur dioxide, oxides of nitrogen and ozone, solar radiation or J O 1 D , and in some campaigns, particle number size distribution by Scanning Mobility Particle Sizer. Events were identified when substantial excursions in particle number count were accompanied by a divergence between the two particle counters indicating a large number of particles in the 3-7 nm diameter range. Criteria have been developed to distinguish between particles within this size range arising from homogeneous nucleation within the atmosphere and from emissions from point sources. Out of a total of 232 days sampling distributed throughout the year, events on only 8 days could be attributed fairly unequivocally to homogeneous nucleation processes, with a further 4 days possibly attributable. Nucleation events occur in winter as well as summer months, but depend, among other things, upon a low particle surface area. Modeling of aerosol dynamical processes for 20 June 1999, indicates that the observations can be explained by a nucleation rate of 6 Â 10 6 cm À3 s À1 at a condensable vapor concentration (as H 2 SO 4 ) of 6.5 Â 10 7 cm À3 . It is inferred that both the nucleation and particle growth processes involve condensable molecules other than, or in addition to, sulfuric acid.
Journal of Geophysical Research, 2003
1] Measurements are reported of particle number concentration at two urban sites within Birmingha... more 1] Measurements are reported of particle number concentration at two urban sites within Birmingham, UK. The measurements were made with a condensation particle counter (TSI Model 3022A) and an ultrafine particle counter (TSI Model 3025) operated in tandem. Other colocated measurements included particle surface area by epiphaniometer, sulfur dioxide, oxides of nitrogen and ozone, solar radiation or J O 1 D , and in some campaigns, particle number size distribution by Scanning Mobility Particle Sizer. Events were identified when substantial excursions in particle number count were accompanied by a divergence between the two particle counters indicating a large number of particles in the 3-7 nm diameter range. Criteria have been developed to distinguish between particles within this size range arising from homogeneous nucleation within the atmosphere and from emissions from point sources. Out of a total of 232 days sampling distributed throughout the year, events on only 8 days could be attributed fairly unequivocally to homogeneous nucleation processes, with a further 4 days possibly attributable. Nucleation events occur in winter as well as summer months, but depend, among other things, upon a low particle surface area. Modeling of aerosol dynamical processes for 20 June 1999, indicates that the observations can be explained by a nucleation rate of 6 Â 10 6 cm À3 s À1 at a condensable vapor concentration (as H 2 SO 4 ) of 6.5 Â 10 7 cm À3 . It is inferred that both the nucleation and particle growth processes involve condensable molecules other than, or in addition to, sulfuric acid.
International Journal of Cancer, 1983
Conditions are described for the development of methotrexate resistance in CCRF/CEM human lymphoi... more Conditions are described for the development of methotrexate resistance in CCRF/CEM human lymphoid cells and an attempt is made to distinguish between those conditions that lead to methotrexate resistance through impairment of cellular transport of methotrexate and those that lead to resistance through enhanced production of dihydrofolate reductase. A restistant line showing a 200-fold enhancement of dihydrofolate reductase has been obtained. The CCRF/CEM human cells are much more sensitive to methotrexate than are murine cells.
Aquacultural Engineering, 2003
Three kinds of locally available plastic biofilter media with different configurations (plastic r... more Three kinds of locally available plastic biofilter media with different configurations (plastic rolls, PVC pipes and scrub pads) were evaluated for their efficiency in organic waste removal from the effluents of an intensive recirculating tilapia culture system. A set of three types of ...
Journal of Ethnopharmacology, 2003
Hemidesmus indicus has been shown to possess significant activity against immunotoxicity and othe... more Hemidesmus indicus has been shown to possess significant activity against immunotoxicity and other pharmacological and physiological disorders. In this communication, we have shown the modulating effect of H. indicus on cumene hydroperoxide-mediated cutaneous oxidative stress and tumor promotion response in murine skin. Cumene hydroperoxide treatment (30 mg per animal) increased cutaneous microsomal lipid peroxidation and induction of xanthine oxidase activity which are accompanied by decrease in the activities of cutaneous antioxidant enzymes and depletion in the level of glutathione. Parallel to these changes a sharp decrease in the activities of phase II metabolizing enzymes was observed. Cumene hydroperoxide treatment also induced the ornithine decarboxylase activity and enhanced the [ 3 H]-thymidine uptake in DNA synthesis in murine skin. Application of ethanolic extract of H. indicus at a dose level of 1.5 and 3.0 mg/kg body weight in acetone prior to that of cumene hydroperoxide treatment resulted in significant inhibition of cumene hydroperoxide-induced cutaneous oxidative stress, epidermal ornithine decarboxylase activity and enhanced DNA synthesis in a dose-dependent manner. Enhanced susceptibility of cutaneous microsomal membrane for lipid peroxidation and xanthine oxidase activity were significantly reduced (P < 0.01). In addition the depleted level of glutathione, inhibited activities of antioxidants and phase II metabolizing enzymes were recovered to significant level (P < 0.05). In summary, our data suggest that H. indicus is an effective chemopreventive agent in skin and capable of ameliorating hydroperoxide-induced cutaneous oxidative stress and tumor promotion.
Pharmacology & Toxicology, 2001
In an earlier communication, we have shown that Tephrosia purpurea ameliorates benzoyl peroxide-i... more In an earlier communication, we have shown that Tephrosia purpurea ameliorates benzoyl peroxide-induced oxidative stress in murine skin . The present study was designed to investigate a chemopreventive efficacy of T. purpurea against N-diethylnitrosamine-initiated and potassium bromate-mediated oxidative stress and toxicity in rat kidney. A single intraperitoneal dose of N-diethylnitrosamine (200 mg/kg body weight) one hr prior to the dose of KBrO 3 (125 mg/kg body weight) increases microsomal lipid peroxidation and the activity of xanthine oxidase and decreases the activities of renal antioxidant enzymes viz., catalase, glutathione peroxidase, glutathione reductase and glucose-6-phosphate dehydrogenase, phase II metabolizing enzymes such as glutathione-S-transferase and quinone reductase and causes depletion in the level of renal glutathione content. A sharp increase in blood urea nitrogen and serum creatinine has also been observed. Prophylactic treatment of rats with T. purpurea at doses of 5 mg/kg body weight and 10 mg/kg body weight prevented N-diethylnitrosamine-initiated and KBrO 3 promoted renal oxidative stress and toxicity. The susceptibility of renal microsomal membrane for iron ascorbate-induced lipid peroxidation and xanthine oxidase activities were significantly reduced (PϽ0.01). The depleted levels of glutathione, the inhibited activities of antioxidant enzymes, phase II metabolizing enzymes and the enhanced levels of serum creatinine and blood urea nitrogen were recovered to a significant level (PϽ0.01). All the antioxidant enzymes were recovered dose-dependently. Our data indicate that T. purpurea besides a skin antioxidant can be a potent chemopreventive agent against renal oxidative stress and carcinogenesis induced by N-diethylnitrosamine and KBrO 3 .
Pharmacy and Pharmacology Communications, 1999
The modulatory effect of Tephrosia purpurea on benzoyl peroxide-induced cutaneous oxidative stres... more The modulatory effect of Tephrosia purpurea on benzoyl peroxide-induced cutaneous oxidative stress is described. Benzoyl peroxide is an effective cutaneous tumour promoter acting through the generation of oxidative stress. Benzoyl peroxide treatment increases cutaneous microsomal lipid peroxidation and hydrogen peroxide generation. The activity of cutaneous antioxidant enzymes, catalase glutathione peroxidase, glutathione reductase and glutathione S-transferase is decreased and the levels of cutaneous glutathione are depleted.
Life Sciences, 2001
Ferula (a genus of many species) commonly known as asafoetida is used as a flavoring agent in foo... more Ferula (a genus of many species) commonly known as asafoetida is used as a flavoring agent in food and is used as a traditional medicine for many diseases in many parts of world. In the current investigation, we report the antioxidant and anticarcinogenic potential of asafoetida ( Ferula narthex ) in swiss albino mice. A single dose of TPA (20nmol/0.2 ml acetone /animal), a known tumor promoter decreased the cellular antioxidant level significantly (p Ͻ 0.01) when applied topically to mice skin. It also induced the ODC activity, rate of DNA synthesis, hydrogen peroxide level, xanthine oxidase activity and protein carbonyl content in mice skin significantly (p Ͻ 0.01). These events are early biomarkers of carcinogenesis. However, the pretreatment of animals with asafoetida (300, 400 and 500 g/200 l acetone / animal) caused the reversal of all events significantly (p Ͻ 0.01). The pretreament of animals with asafoetida recovered the antioxidant level and reversed the induced ODC activity and DNA synthesis significantly (p Ͻ 0.01). We conclude that asafoetida is a potent antioxidant and can afford protection against free radical mediated diseases such as carcinogenesis.
Journal of Ethnopharmacology, 2000
The hepatoprotective activity of the 50% ethanol extract of the bark of Lawsonia alba syn. L. ine... more The hepatoprotective activity of the 50% ethanol extract of the bark of Lawsonia alba syn. L. inermis was investigated against the carbon tetrachloride-induced oxidative stress. Pretreatment of rats with doses of 250 and 500 mg/kg of the plant extract significantly (PB 0.001) lowered serum transaminases (GOT and GPT) and LDH levels, respectively, in a dose dependent manner against the significant (P B0.001) rise of these damage marker enzymes when challenged with CCl 4 (1 ml/kg, orally). Parallel to these changes, the plant extract prevented CCl 4 -induced oxidative stress by significantly maintaining the levels of reduced glutathione (GSH), its metabolizing enzymes and simultaneously inhibiting the production of free radicals. Pretreatment of rats with the extract also inhibited the peroxidation of microsomal lipids in a dose-dependent manner.
Pharmacological Research, 2001
The modulating effect of Lupeol [lup-20(29)-en-3 beta -ol], a triterpene found in many fruits and... more The modulating effect of Lupeol [lup-20(29)-en-3 beta -ol], a triterpene found in many fruits and medicinal plants, on benzoyl peroxide-induced tumor promotion responses or tumor promotion in murine skin is described. Benzoyl peroxide is an effective cutaneous tumor promoter acting through the generation of oxidative stress, the induction of ornithine decarboxylase activity and the enhancement of DNA synthesis. Benzoyl peroxide treatment increases cutaneous microsomal lipid peroxidation and hydrogen peroxide generation. The activity of the cutaneous antioxidant enzymes, namely catalase, glutathione peroxidase, glutathione reductase and glutathione S-transferase, is decreased and levels of cutaneous glutathione are depleted. Benzoyl peroxide treatment also induces ornithine decarboxylase activity and enhances [3H]thymidine uptake in DNA synthesis. Prophylactic treatment of mice with lupeol (0.75 and 1.5 mg per animal) 1 hour before benzoyl peroxide treatment resulted in a diminution of benzoyl peroxide-mediated damage. The susceptibility of cutaneous microsomal membrane to lipid peroxidation and hydrogen peroxide generation was significantly reduced (P&amp;lt; 0.01 and P&amp;lt; 0.01, respectively). In addition, depleted levels of glutathione and inhibited activity of antioxidant enzymes were recovered to a significant level (P&amp;lt; 0.01, P&amp;lt; 0.05 and P&amp;lt; 0.01, respectively). Similarly, the elevated ornithine decarboxylase activity and enhanced thymidine uptake in DNA synthesis were inhibited significantly (P&amp;lt; 0.05) in a dose-dependent manner. The protective effect of lupeol was dose dependent in all parameters. The results suggest that lupeol is an effective skin chemopreventive agent that may suppress benzoyl peroxide-induced cutaneous toxicity.
Pharmacological Research, 2001
In recent years, considerable emphasis has been placed on identifying new cancer chemopreventive ... more In recent years, considerable emphasis has been placed on identifying new cancer chemopreventive agents, which could be useful for the human population. Tephrosia purpurea has been shown to possess significant activity against hepatotoxicity, pharmacological and physiological disorders. Earlier we showed that Tephrosia purpurea inhibits benzoyl peroxide-mediated cutaneous oxidative stress and toxicity. In the present study, we therefore assessed the effect of Tephrosia purpurea on 12-O-tetradecanoyl phorbal-13-acetate (TPA; a well-known phorbol ester) induced cutaneous oxidative stress and toxicity in murine skin. The pre-treatment of Swiss albino mice with Tephrosia purpurea prior to application of croton oil (phorbol ester) resulted in a dose-dependent inhibition of cutaneous carcinogenesis. Skin tumor initiation was achieved by a single topical application of 7,12-dimethyl benz(a)anthracene (DMBA) (25 microg per animal per 0.2 ml acetone) to mice. Ten days later tumor promotion was started by twice weekly topical application of croton oil (0.5% per animal per 0.2 ml acetone, v /v). Topical application of Tephrosia purpurea 1 h prior to each application of croton oil (phorbol ester) resulted in a significant protection against cutaneous carcinogenesis in a dose-dependent manner. The animals pre-treated with Tephrosia purpurea showed a decrease in both tumor incidence and tumor yield as compared to the croton oil (phorbol ester)-treated control group. In addition, a significant reduction in TPA-mediated induction in cutaneous ornithine decarboxylase (ODC) activity and [3H]thymidine incorporation was also observed in animals pre-treated with a topical application of Tephrosia purpurea. The effect of topical application of Tephrosia purpurea on TPA-mediated depletion in the level of enzymatic and non-enzymatic molecules in skin was also evaluated and it was observed that topical application of Tephrosia purpurea prior to TPA resulted in the significant recovery of TPA-mediated depletion in the level of these molecules, namely glutathione, glutathione S-transferase, glutathione reductase and catalase. From these data we suggest that Tephrosia purpurea can abrogate the tumor-promoting effect of croton oil (phorbol ester) in murine skin.
Pharmacological Research, 2002
Vitis vinifera (grapes) is used as a fruit worldwide and known for its pharmacological properties... more Vitis vinifera (grapes) is used as a fruit worldwide and known for its pharmacological properties. The present paper assesses the chemopreventive potential of Vitis vinifera against 12-O-tetradecanoyl-13phorbol acetate (TPA)-mediated tumor promotion in 7,12-dimethyl-benz[a]anthracene (DMBA) initiated mice skin. Skin tumor initiation was achieved by a single topical application of DMBA (40 µg/animal/0.20 ml acetone) to mice. Two weeks after the initiation, promoting agent, TPA (5.0 µg/animal/0.2 ml acetone) was applied two times a week for 20 weeks. Pretreatment of Vitis vinifera 1 h prior to each application of TPA resulted in protection against cutaneous tumorigenesis in dose-dependent manner. This inhibition was evident when tumor data was considered as the percentage of mice with tumor and the number of tumors per mouse. We have shown that typical application of Vitis vinifera prior to that of TPA resulted in significant inhibition against TPA-caused induction of epidermal ODC activity (P < 0.001) and DNA synthesis. Application of Vitis vinifera at a dose level of 5.0 mg and 10.0 mg kg −1 body weight in acetone prior to that of TPA treatment resulted in partial significant inhibition of oxidative stress in dose-dependent manner. The concomitant increase in the microsomal lipid peroxidation and xanthine oxidase activities were significantly reduced (P < 0.001). In addition, the depleted level of glutathione and inhibited activities of antioxidant enzymes were recovered to the partial significant level. Hence, it can be suggested that Vitis vinifera can be used as a chemopreventive agent against oxidative stress and carcinogenesis.
Pharmacology & Toxicology, 2000
In recent years, considerable efforts have been made to identify new chemopreventive agents which... more In recent years, considerable efforts have been made to identify new chemopreventive agents which could be useful for man. Myrica nagi, a subtropical shrub, has been shown to possess significant activity against hepatotoxicity and other pharmacological and physiological disorders. We have shown a chemopreventive effect of Myrica nagi on cumene hydroperoxide-induced cutaneous oxidative stress and toxicity in mice. Cumene hydroperoxide treatment at a dose level of 30 mg/animal/0.2 ml acetone enhances susceptibility of cutaneous microsomal membrane for iron-ascorbateinduced lipid peroxidation and induction of xanthine oxidase activity which are accompanied by decrease in the activities of cutaneous antioxidant enzymes such as catalase, glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase and depletion in the level of cutaneous glutathione. Parallel to these changes a sharp decrease in the activities of phase II metabolizing enzymes such as glutathione S-transferase and quinone reductase has been observed. Application of Myrica nagi at doses of 2.0 mg and 4.0 mg/kg body weight in acetone prior to that of cumene hydroperoxide (30 mg/animal/0.2 ml acetone) treatment resulted in significant inhibition of cumene hydroperoxide-induced cutaneous oxidative stress and toxicity in a dose-dependent manner. Enhanced susceptibility of cutaneous microsomal membrane for lipid peroxidation induced by iron ascorbate and xanthine oxidase activities were significantly reduced (P∞0.05). In addition the depleted level of glutathione, the inhibited activities of antioxidants, and phase II metabolizing enzymes were recovered to a significant level (P∞0.05). The protective effect of Myrica nagi was dose-dependent. In summary our data suggest that Myrica nagi is an effective chemopreventive agent in skin and capable of ameliorating cumene hydroperoxideinduced cutaneous oxidative stress and toxicity.