-
[show abstract]
[hide abstract]
ABSTRACT: AIM: Constitutive activation of nuclear factor-kappaB (NF-κB) and Akt has been implicated in chemoresistance as well as inhibition of apoptosis to cisplatin (CDDP), therefore, we examined whether (-) epigallocateocatechin-3-gallate (EGCG) or theaflavins (TF) could sensitize human cancer cells to CDDP via induction of apoptosis mediated by the inactivation of NF-κB and Akt signaling. MAIN METHODS: Human cervical cancer cells (HeLa and SiHa cells) were treated with EGCG or TF and CDDP alone and with their combinations, further their effects on cell viability were evaluated. Western blotting was used for examining the apoptotic signaling proteins and inhibition of NF-κB activation. Levels of reactive oxygen species (ROS) production and mitochondria membrane potential (ΔΨm) were examined by flow cytometry. KEY FINDINGS: The combined treatment of EGCG or TF with CDDP elicited significant inhibition of cell growth in comparison to either of them in both cell lines (p<0.05). Combinatorial treatment of both compounds potentially induced apoptosis by inhibiting the activation of Akt and NF-κB through blocking phosphorylation of inhibitor kappa Bα. These combinations acted in concert to induce increase in ROS level, release of cytochrome-c and expression of p53 and Bax, with decrease in cellular glutathione contents, ΔΨm, and Bcl-2 expression, thereby eventually resulting in the activation of caspases, poly(ADP)ribose polymerase cleavage and apoptosis of cancer cells. SIGNIFICANCE: Study suggests that both EGCG and TF chemosensitize the cervical cancer cells to CDDP-induced growth inhibition and apoptosis. By these combinations ~4 folds increase in CDDP induced-apoptosis with dose advantage of ~3 times could be achieved.
Life sciences 02/2013; · 2.56 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This study was conducted to assess the predictive value of p-glycoprotein (p-gp) and p53 immunoexpression in human papillomavirus (HPV) infected cases of cervical dysplasia. Expression of both p-gp and p53 proteins was detected in cervical smears from 177 squamous intraepithelial lesions (SIL) cases along with 183 "atypical squamous cells of unknown significance" (ASCUS) and 150 normal cases. HPV 16 and 18 infection was detected by polymerase chain reaction using type-specific primers for HPV sub-types. There were no significant detectable p53 and p-gp expression in the normal cervix smears (p>0.05). In the ASCUS group 10 cases were positive for both p53 and p-gp immunoreactivity. In cervical dysplasia cases, p53 was positive in 86 (48.58%) while p-gp was positive in 93 (52.54%) and the two markers showed a highly significant correlation (r=0.92, p<0.001). Expression of p53 and p-gp was associated with grade of SIL (p<0.001). A positive correlation between the presence of HPV and expression of proteins p53 and p-gp in smears of patients with cervical lesions was also noted (p<0.001). Thus, p53 and p-gp immunostaining in cervical smears may act as an auxiliary biomarker for detection of HPV-associated cervical lesions. Additionally, a significant positive correlation between ascending grades of SIL and labeling indices of markers suggests that p53 and p-gp can be used as an adjunct to cytomorphological interpretation of conventional cervical Pap smears.
Asian Pacific journal of cancer prevention: APJCP 01/2012; 13(12):6039-45. · 0.66 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Fruits, vegetables, spices, herbs and/or beverages are typical foods containing various phytochemicals that have been used for prevention and treatment of a variety of human ailments since time immemorial. Nowadays, a large number of individuals are motivating towards the use of phytochemicals inorder to prevent or treat chronic diseases. Recent research efforts have been greatly emphasized on the recognition of naturally occurring plant derived substances that are capable of inhibiting, retarding or reversing the development of cancer. Several epidemiological annotations and a number of laboratory studies have indicated cancer chemopreventive and anti-carcinogenic potential of plant derived agents that have been traditionally used for treatment of varied human disorders in different parts of the globe. Molecular mechanisms which are involved for eliciting the effects of phytochemicals in cancerous cells are noticed in a range of experimental systems. This has opened up new avenue for researchers working in the field of chemoprevention and merits further scrutiny to establish the role of phytochemicals in prevention of fatal human diseases like cancer.
Frontiers in bioscience (Elite edition) 01/2012; 4:426-52.
-
[show abstract]
[hide abstract]
ABSTRACT: Limited outcomes from earlier chemopreventive studies have necessitated that some modifications be made to get better efficacy. It is proposed that cancer prevention is more feasible than treatment, and this could be achieved effortlessly with use of multiple agents competent of targeting multiple targets. This study was initiated to examine the chemopreventive efficacy of pomegranate fruit extract (PFE) and diallyl sulfide (DAS), alone and in combination, using 2-stage mouse skin tumorigenesis model. PFE and DAS alone delayed onset and tumor incidence by ∼55% and ∼45%, respectively, while their combination at low doses synergistically decreased tumor incidence more potentially (∼84%, p<0.01). In addition, regression in tumor volume was seen with continuous combinatorial treatment (p<0.01). Mechanistic studies revealed that this inhibition was associated with decreased expression of phosphorylated ERK1/2, JNK1 and activated NF-κB/p65, IKKα, IκBα phosphorylation and degradation in skin tissue/tumor. Histological and cell death analysis also confirmed that combined PFE and DAS inhibit cellular proliferation and markedly induce apoptosis than the single agents. Altogether, our results suggest that PFE and DAS in combination impart better suppressive activity than either of these agents alone and provide support that development of novel combination therapies/chemoprevention using dietary agents will be more beneficial against cancer.
Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association 03/2011; 49(7):1511-20. · 2.99 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Bromelain, obtained from pineapple, is already in use clinically as adjunct in chemotherapy. Our objective was to test its ability to act as a sole anti-cancer agent. Therefore, we describe its anti-proliferative, anti-inflammatory and subsequent anti-cancer effects in vitro, against human epidermoid carcinoma-A431 and melanoma-A375 cells. Bromelain exhibited reduction in proliferation of both these cell-lines and suppressed their potential for anchorage-independent growth. Further, suppression of inflammatory signaling by bromelain was evident by inhibition of Akt regulated-nuclear factor-kappaB activation via suppression of inhibitory-kappaBα phosphorylation and concomitant reduction in cyclooxygenase-2. Since, the inflammatory cascade is well-known to be closely allied to cancer; we studied the effect of bromelain on events/molecules central to it. Bromelain caused depletion of intracellular glutathione and generation of reactive oxygen-species followed by mitochondrial membrane depolarization. This led to bromelain-induced cell-cycle arrest at G(2)/M phase which was mediated by modulation of cyclin B1, phospho-cdc25C, Plk1, phospho-cdc2, and myt1. This was subsequently followed by induction of apoptosis, indicated by membrane-blebbing, modulation of Bax-Bcl-2 ratio, Apaf-1, caspase-9, and caspase-3; chromatin-condensation, increase in caspase-activity and DNA-fragmentation. Bromelain afforded substantial anti-cancer potential in these settings; hence we suggest it as a potential prospect for anti-cancer agent besides only an additive in chemotherapy.
Molecular Carcinogenesis 03/2011; 51(3):231-43. · 3.16 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Anti-cancer potential of polymer based nanoparticle of EGCG and TF alone and in combination with anti-cancer drug cisplatin have been studied in human cancer lines: A549 (lung carcinoma), HeLa (cervical carcinoma) and THP-1 (acute monocytic leukemia) using cell proliferation assay and cell cycle analysis. Encapsulated polyphenols retained biological effectiveness with over 20-fold dose advantage than EGCG/TF in exerting anti-cancer effects and also enhanced the potential of a widely used anti-cancer drug cisplatin. Subsequently, encapsulated polyphenols alone or in combination with cisplatin were more effective in inhibiting cell proliferation, metastasis, angiogenesis and apoptosis biomarkers. Collectively, our observations reveal that nanoparticle-mediated delivery of phytochemicals could serve as a basis for enhancing bioavailability and limiting the unwanted toxicity of chemotherapeutic agents.
Journal of Biomedical Nanotechnology 02/2011; 7(1):202. · 4.22 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Cancer chemoprevention by natural dietary agents has received considerable importance because of their cost-effectiveness and wide safety margin. However, single agent intervention has failed to bring the expected outcome in clinical trials; therefore, combinations of chemopreventive agents are gaining increasing popularity. The present study aims to evaluate the combinatorial chemopreventive effects of resveratrol and black tea polyphenol (BTP) in suppressing two-stage mouse skin carcinogenesis induced by DMBA and TPA. Resveratrol/BTP alone treatment decreased tumor incidence by ∼67% and ∼75%, while combination of both at low doses synergistically decreased tumor incidence even more significantly by ∼89% (p<0.01). This combination also significantly regressed tumor volume and number (p<0.01). Mechanistic studies revealed that this combinatorial inhibition was associated with decreased expression of phosphorylated mitogen-activated protein kinase family proteins: extracellular signal-regulated kinase 1/2, c-Jun N-terminal kinase 1/2, p38 and increased in total p53 and phospho p53 (Ser 15) in skin tissue/tumor. Treatment with combinations of resveratrol and BTP also decreased expression of proliferating cell nuclear antigen in mouse skin tissues/tumors than their solitary treatments as determined by immunohistochemistry. In addition, histological and cell death analysis also confirmed that resveratrol and BTP treatment together inhibits cellular proliferation and markedly induces apoptosis. Taken together, our results for the first time lucidly illustrate that resveratrol and BTP in combination impart better suppressive activity than either of these agents alone and accentuate that development of novel combination therapies/chemoprevention using dietary agents will be more beneficial against cancer. This promising combination should be examined in therapeutic trials of skin and possibly other cancers.
PLoS ONE 01/2011; 6(8):e23395. · 4.09 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Phytochemicals present in tea, particularly polyphenols, have anticancer properties against several cancer types. However, studies elucidating the role and the mechanism(s) of action of tea polyphenols in cervical cancer are sparse. In this study, we investigated the mechanism of antiproliferative and apoptotic actions exerted by tea polyphenols on human papilloma virus-18-positive HeLa cervical cancer cells. Treatment of green tea polyphenol (-)-epigallocatechin gallate (EGCG) and black tea polyphenol theaflavins (TF) in HeLa cells showed a marked concentration- and time-dependent inhibition of proliferation and induced sub-G1 phase in a dose-dependent manner after 24 h. There was an attenuation of mitochondrial membrane potential with the increase of reactive oxygen species generation, p53 expression, Bax/Bcl-2 ratio, cytochrome-c release, and cleavage of procaspase-3 and -9 and poly(ADP-ribose)-polymerase, indicating the participation of a mitochondria related mechanism. In addition, EGCG as well as TF inhibited activation of Akt and nuclear factor-kappaB (NF-kappaB) via blocking phosphorylation and subsequent degradation of inhibitor of kappaBalpha and kappaBbeta subunits, thereby downregulating cyclooxygenase-2. Additionally, the protein level of cyclin D1, a transcriptional target of NF-kappaB, was also reduced significantly. Thus, we can conclude that tea polyphenols inhibit the growth of cervical cancer cells by inducing apoptosis and regulating NF-kappaB and Akt.
Oncology Research Featuring Preclinical and Clinical Cancer Therapeutics 01/2011; 19(6):245-57. · 1.30 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Polo-like kinase 1 (Plk1), a critical regulator of mitotic entry, progression and exit, has been shown to be involved in a variety of cancers and thus is becoming an attractive target for cancer management. In case of DNA damage, Plk1 not only inhibits p53 independent apoptosis by dysfunctioning p73α but also allows cells to recover from growth arrest. Here, we showed the effects of knocking down plk1 gene through small interference RNA (siRNA) on cell cycle progression, proliferation and chemosensitivity of p53 mutant A431 cells to cisplatin (CDDP). The expression of Plk1 was measured by RT-PCR and Western blotting. Anti-proliferative response accompanied with cell cycle arrest in G(2)/M phase and induction of cell death was recorded following Plk1 knockdown. Furthermore, cells following knockdown of Plk1, which induced increase of Cyclin B1, p-Cdc2 and p73α with a decrease in p-Cdc25C, were more sensitive to CDDP. CDDP treatment induced nuclear translocation and co-localization of Plk1 with p73α whereas combination of CDDP and Plk1siRNA upregulated the expression of p73α protein in a synergistic manner thereby leading to an increase up to ∼5 folds in CDDP-induced cell death. The increase in caspase-3 activity indicated apoptosis as a contributor in the total cell death. Conclusively, plk1 gene silencing can enhance the sensitivity of A431 cells to low doses of CDDP by upregulating p73α expression and thus can be a revolutionary approach in cancer chemotherapy.
Biochemical pharmacology 11/2010; 80(9):1326-34. · 4.25 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Repeated heating of vegetable oils at high temperatures during cooking is a very common cooking practice. Repeated heating of edible oils can generate a number of compounds, including polycyclic aromatic hydrocarbons (PAH), some of which have been reported to have carcinogenic potential. Consumption of these repeatedly heated oils can pose a serious health hazard. The objectives of the present study were to evaluate the genotoxic and carcinogenic risks associated with the consumption of repeatedly heated coconut oil (RCO), which is one of the commonly consumed cooking and frying medium. The PAH were analysed using HPLC in fresh CO, single-heated CO (SCO) and RCO. Results revealed the presence of certain PAH, known to possess carcinogenic potential, in RCO when compared with SCO. Oral intake of RCO in Wistar rats resulted in a significant induction of aberrant cells (P<0·05) and micronuclei (P<0·05) in a dose-dependent manner. Oxidative stress analysis showed a significant (P<0·05) decrease in the levels of antioxidant enzymes such as superoxide dismutase and catalase with a concurrent increase in reactive oxygen species and lipid peroxidation in the liver. In addition, RCO given alone and along with diethylnitrosamine for 12 weeks induced altered hepatic foci as noticed by alteration in positive (γ-glutamyl transpeptidase and glutathione-S-transferase) and negative (adenosine triphosphatase, alkaline phosphatase and glucose-6-phosphatase) hepatospecific biomarkers. A significant decrease in the relative and absolute hepatic weight of RCO-supplemented rats was recorded (P<0·05). In conclusion, dietary consumption of RCO can cause a genotoxic and preneoplastic change in the liver.
The British journal of nutrition 11/2010; 104(9):1343-52. · 3.45 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Repeated boiling of vegetable oils at high temperature in cooking and frying is a very common practice and leads to the formation of a class of toxic substances. Among them, polycyclic aromatic hydrocarbons (PAHs) are well-documented for their mutagenic/carcinogenic potential. The objectives of the present study were to evaluate the genotoxic and carcinogenic risks associated with the consumption of repeatedly boiled sunflower oil, which is one of the commonly consumed vegetable oils in southeast Asian countries. The presence of PAHs was analyzed using high-performance liquid chromatography (HPLC) methods in fresh, single-boiled, and repeatedly-boiled sunflower oil (FSO, SBSO, and RBSO) samples. A higher amount of known carcinogenic/mutagenic PAHs in RBSO samples were shown, as compared to FSO and SBSO. Oral administration of RBSO in Wistar rats resulted in significant induction of aberrant cells (p < 0.05) and micronuclei (p < 0.05) incidence in a dose-dependent manner. Oxidative stress analysis also showed a significant decrease in levels of antioxidant enzymes, such as superoxide dismutase and catalase, with a concurrent increase in reactive oxygen species and lipid peroxidation in animals following RBSO consumption, as compared to FSO or SBSO (p < 0.05). Additionally, RBSO administration alone and along with diethylnitrosamine for 12 weeks induced altered hepatic foci, as noticed by the alteration in positive (γ-glutamyl transpeptidase and glutathione-S-transferase) and negative (adenosine-triphosphatase, alkaline phosphatase, and glucose-6-phosphatase) liver biomarkers. A significant decrease in the relative and absolute hepatic weight in RBSO-supplemented rats was also noted (p < 0.05).
Journal of Agricultural and Food Chemistry 10/2010; · 2.82 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Our interest in development of hyaluronidase inhibitors as male antifertility agents led to identification of Terminalia chebula (T. chebula) plant with hyaluronidase (HAase) inhibitory activity of human spermatozoa ( approximately 93% inhibition) and rat caudal epididymal spermatozoa ( approximately 86% inhibition) in vitro at 30 mg/ml. We further demonstrated inhibition of hyaluronidase activity of testis and epididymal spermatozoa in vivo coincident with antispermatogenic activity and contraceptive efficacy of TC extract administered at 50 and 100mg/kg/day orally for 60 days in male albino rats. The significant decrease in motility, count and increase in morphological abnormalities of epididymal spermatozoa and severe reduction in fertility (-100%) of male rats treated with T. chebula fruit extract at 100mg/kg dose could be attributed to either direct effect on testis or direct or indirect interference with sperm maturation in epididymis, and/or inhibition of testicular and epididymal sperm hyaluronidase enzyme in vivo probably caused by flavonoids like tannins present in T. chebula.
Reproductive Toxicology 11/2009; 29(2):214-24. · 3.23 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To analyze aberrant expression of the apoptotic protein p53 and the anti-apoptotic protein Bcl-2 in premalignant lesions of the uterine cervix induced by human papillomavirus (HPV) infection and its significance for early diagnosis of cervical cancer.
Cytological adequate smears (n = 382) from various grades of squamous intraepithelial lesions (SILs; n = 142), 'atypical squamous cells of unknown significance' (ASCUS; n = 128) and normal tissue (n = 112) were investigated immunocytochemically for aberrant expression of p53 and Bcl-2 proteins using the streptavidin-biotin-peroxidase method; HPV status was analyzed in cervical smears using general and type-specific primers.
HPV-DNA of any type was detected in 25.7% (98/382) of cases. HPV16 was seen in 58.2% (57/98), HPV18 in 20.4% (20/98) and other HPV types in 21.4% (21/98). Abnormal nuclear expression of p53 protein and cytoplasmic expression of Bcl-2 protein were noted in cervical dysplasia and an association with the presence of HPV16/HPV18 was noted. The intensity of immunoreactivity for p53 and Bcl-2 proteins varied between different cytological grades of cervical smears. Follow-up data revealed that cases with high-risk HPV and co-induced expression of apoptosis-regulatory proteins presented a trend to progressive disease.
The detection of both p53 and Bcl-2 proteins in cervical smears can be used as independent diagnostic marker for early-stage HPV-associated cervical cancer.
Tumor Biology 11/2009; 30(5-6):276-85. · 1.94 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To unravel the molecular mechanisms underlying the chemopreventive potential of [6]-gingerol, a pungent ingredient of ginger rhizome (Zingiber officinale Roscoe, Zingiberaceae), against benzo[a]pyrene (B[a]P)-induced mouse skin tumorigenesis.
Topical treatment of [6]-gingerol (2.5 muM/animal) was given to the animals 30 min prior and post to B[a]P (5 mug/animal) for 32 weeks. At the end of the study period, the skin tumors/tissues were dissected out and examined histopathologically. Flow cytometry was employed for cell cycle analysis. Further immunohistochemical localization of p53 and regulation of related apoptogenic proteins were determined by Western blotting.
Chemopreventive properties of [6]-gingerol were reflected by delay in onset of tumorigenesis, reduced cumulative number of tumors, and reduction in tumor volume. Cell cycle analysis revealed that the appearance of sub-G1 peak was significantly elevated in [6]-gingerol treated animals with post treatment showing higher efficacy in preventing tumorigenesis induced by B[a]P. Moreover, elevated apoptotic propensity was observed in tumor tissues than the corresponding non-tumor tissues. Western blot analysis also showed the same pattern of chemoprevention with [6]-gingerol treatment increasing the B[a]P suppressed p53 levels, also evident by immunohistochemistry, and Bax while decreasing the expression of Bcl-2 and Survivin. Further, [6]-gingerol treatment resulted in release of Cytochrome c, Caspases activation, increase in apoptotic protease-activating factor-1 (Apaf-1) as mechanism of apoptosis induction.
On the basis of the results we conclude that [6]-gingerol possesses apoptotic potential in mouse skin tumors as mechanism of chemoprevention hence deserves further investigation.
Cancer Chemotherapy and Pharmacology 08/2009; 65(4):687-96. · 2.83 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Due to lack of validated screening methods and hence poor prognosis, treatment of lung cancer has not still improved up to the expectations. Therefore, risk of lung cancer needs to be minimized by efficient preventive measures. Tea (Camellia sinensis) and its bioactive polyphenols have been associated with prevention of human cancer for several organs. Thus, intake of tea polyphenols seems to be a viable mean to control lung cancer burden. In the present study, we studied the chemopreventive effects of green tea polyphenols (GTP) and black tea polyphenols (BTP) against diethylnitrosoamine (DEN) induced lung tumors in Swiss albino mice.
Chemopreventive potential of tea polyphenols, was recorded as evident by, low incidence of alveologenic tumors in lungs of animals at tested doses (0.1% and 0.2% of both GTP and BTP) when compared with DEN (20 mg/kg b wt) treated animals. As a mechanism of cancer chemoprevention cellular signaling pathways were also targeted. GTP and BTP treatment inhibited the expression of Akt, cyclooxygenase-2 and inactivated nuclear factor-kappa B via blocking phosphorylation and subsequent degradation of IkappaB alpha.
Thus, the study suggests that polyphenolic constituents of both cultivars of tea, i.e. green and black, have chemopreventive effects in DEN induced lung tumorigenesis in Swiss albino mice.
Investigational New Drugs 07/2009; 28(4):466-71. · 3.36 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Cervical cancer is the second most common malignant neoplasm in women, in terms of both incidence and mortality rates worldwide. The polyphenolic constituents of tea (Camellia sinensis) have gained considerable attention because of its anti-cancer properties against a variety of cancers. Here we studied the effects of green and black tea polyphenols (GTP and BTP), on cellular proliferation and cell death in the SiHa cells (human cervical cancer) expressing the human papilloma virus (HPV)-16. The result showed that both GTP and BTP inhibited proliferation of cells in dose and time dependent manner. Cell cycle analysis showed anti-proliferative effect of GTP which is associated with an increase in the G2/M phase and apoptotic effect of BTP in 24 h treated SiHa cells. Further, on increase of incubation time for 48 h, GTP caused induction of apoptosis up to 20% of SiHa cells. The role GTP and BTP in apoptosis was further confirmed by reduction in mitochondrial membrane potential and increased levels of membrane phosphatidylserine. Thus, our data suggests that tea polyphenols exhibit anti-cancer potential against cervical cancer by inhibition of cell growth and induction of apoptosis.
Investigational New Drugs 04/2009; 28(3):216-24. · 3.36 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Glyphosate (N-(phosphonomethyl) glycine, C(3)H(8)NO(5)P), a herbicide, used to control unwanted annual and perennial plants all over the world. Nevertheless, occupational and environmental exposure to pesticides can pose a threat to nontarget species including human beings. Therefore, in the present study, genotoxic effects of the herbicide glyphosate were analyzed by measuring chromosomal aberrations (CAs) and micronuclei (MN) in bone marrow cells of Swiss albino mice. A single dose of glyphosate was given intraperitoneally (i.p) to the animals at a concentration of 25 and 50 mg/kg b.wt. Animals of positive control group were injected i.p. benzo(a)pyrene (100 mg/kg b.wt., once only), whereas, animals of control (vehicle) group were injected i.p. dimethyl sulfoxide (0.2 mL). Animals from all the groups were sacrificed at sampling times of 24, 48, and 72 hours and their bone marrow was analyzed for cytogenetic and chromosomal damage. Glyphosate treatment significantly increases CAs and MN induction at both treatments and time compared with the vehicle control (P < .05). The cytotoxic effects of glyphosate were also evident, as observed by significant decrease in mitotic index (MI). The present results indicate that glyphosate is clastogenic and cytotoxic to mouse bone marrow.
Journal of Toxicology 01/2009; 2009:308985.
-
[show abstract]
[hide abstract]
ABSTRACT: Tea (Camellia sinensis) is one of the most widely used beverages worldwide and tea consumption has been shown to have an inverse correlation to the incidence of human cancers in epidemiological and experimental studies. In the present study, the protective effects of green tea polyphenols (GTP) and black tea polyphenols (BTP) in Wistar rats were assessed by medium-term bioassay, using altered hepatic foci (AHF) as end point. Animals were exposed to a single dose of diethylnitrosamine (DEN; 200 mg/kg body weight intraperitoneally), and GTP (1%) and BTP (1%) were then administered orally together with 0.05% 2-acetyl aminofluorene (2-AAF) crushed and mixed in the diet for 8 weeks. Numbers of AHF were scored and analyzed by quantitative stereology using the Image analysis system from frozen liver tissue sections. Tea polyphenol supplementation resulted in a significant protection against AHF induction in Wistar rats. In addition, levels of the positive biomarkers: gamma-glutamyl transpeptidase and glutathione-S-transferase (placental form) were reduced with GTP and BTP supplementation. Levels of the negative biomarkers adenosine triphosphatase and glucose-6-phosphatase were also restored by GTP and BTP administration. Thus, these results show the hepatoprotective effects of GTP and BTP against DEN- and 2-AAF-induced AHF development.
Investigational New Drugs 01/2009; 27(6):526-33. · 3.36 Impact Factor
-
Diagnostic Cytopathology 04/2008; 36(3):194-5. · 1.16 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To investigate antioxidant potential of lupeol/mango pulp extract (MPE) in testosterone induced oxidative stress in prostate of male Swiss albino mice.
Oral treatment of lupeol (1 mg/animal) and MPE (1 mL [20% w/v]/animal) was given separately to animals along with subcutaneous injection of testosterone (5 mg/kg body weight) consecutively for 15 days. At the end of the study period, the prostate was dissected out for the determination of reactive oxygen species (ROS) levels, lipid peroxidation and antioxidant enzymes status (catalase, superoxide dismutase, glutathione reductase, glutathione-S-transferase).
In testosterone treated animals, increased ROS resulted in depletion of antioxidant enzymes and increase in lipid peroxidation in mouse prostate. However, lupeol/MPE treatment resulted in a decrease in ROS levels with restoration in the levels of lipid peroxidation and antioxidant enzymes.
The results of the present study demonstrate that lupeol/MPE are effective in combating oxidative stress-induced cellular injury of mouse prostate. Mango and its constituents, therefore, deserve study as a potential chemopreventive agent against prostate cancer.
Asian Journal of Andrology 04/2008; 10(2):313-8. · 1.52 Impact Factor
