Chemotherapeutic effect of tangeretin, a polymethoxylated flavone studied in 7, 12-dimethylbenz(a)anthracene induced mammary carcinoma in experimental rats

Protective and curative effects of the sea cucumber Holothuria atra extract against DMBA-induced hepatorenal diseases in rats

Oxidative stress is a common mechanism contributing to the initiation and progression of hepatic damage. Hence there is a great demand for the development of agents with potent antioxidant effect. The aim of the present study is to evaluate the efficacy of Holothuria atra extract (HaE) as an antioxidant against 7,12-dimethylbenz[a]anthracene- (DMBA-) induced hepatorenal dysfunction. Experimental animals were divided into two main groups: protective and curative. Each group was then divided into five subgroups pre- or posttreated either with distilled water (DMBA subgroups) or with HaE (200 mg/kg body weight) for seven and fourteen days. Single oral administration of DMBA (15 mg/kg body weight) to Wistar rats resulted in a significant increase in the serum liver enzymes and kidney function's parameters. DMBA increased level of liver malondialdehyde (MDA), decreased levels of reduced glutathione (GSH), glutathione-S-transferase (GST), superoxide dismutase (SOD), and catalase (CAT) in the liver tissue, and induced liver histopathological alterations. Pre- or posttreatment with HaE orally for 14 days significantly reversed the hepatorenal alterations induced following DMBA administration. In conclusion, HaE exhibits good hepatoprotective, curative, and antioxidant potential against DMBA-induced hepatorenal dysfunction in rats that might be due to decreased free radical generation.

Stimulation effect of wide type CFTR chloride channel by the naturally occurring flavonoid tangeretin

Cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-activated chloride channel expressed in the apical membrane of serous epithelial cells. Both deficiency and overactivation of CFTR may cause fluid and salt secretion related diseases. In the present study, we identified tangeretin from Pericarpium Citri Reticulatae Viride as a CFTR activator using high-throughput screening based on FRT cell-based fluorescence assay. The activation effect of tangeretin on CFTR chloride channel and the possible underlying mechanisms were investigated. Fluorescence quenching tests showed that tangeretin dose- and time-dependently activated CFTR chloride channel, the activity had rapid and reversible characteristics and the activation effect could be completely reversed by the CFTR specific blocker CFTRinh-172. Primary mechanism studies indicated that the activation effect of tangeretin on CFTR chloride channel was FSK dependent as well as had additional effect with FSK and IBMX suggesting that tangeretin activates CFTR by direct interacting with the protein. Ex-vivo tests revealed that tangeretin could accelerate the speed of the submucosal gland fluid secretion. Short-circuit current measurement demonstrated that tangeretin activated rat colonic mucosa chloride current. Thus, CFTR Cl(-) channel is a molecular target of natural compound tangeretin. Tangeretin may have potential use for the treatment of CFTR-related diseases like cystic fibrosis, bronchiectasis and habitual constipation.

Anticancer activities of citrus peel polymethoxyflavones related to angiogenesis and others

Citrus is a kind of common fruit and contains multiple beneficial nutrients for human beings. Flavonoids, as a class of plant secondary metabolites, exist in citrus fruits abundantly. Due to their broad range of pharmacological properties, citrus flavonoids have gained increased attention. Accumulative in vitro and in vivo studies indicate protective effects of polymethoxyflavones (PMFs) against the occurrence of cancer. PMFs inhibit carcinogenesis by mechanisms like blocking the metastasis cascade, inhibition of cancer cell mobility in circulatory systems, proapoptosis, and antiangiogenesis. This review systematically summarized anticarcinogenic effect of citrus flavonoids in cancer therapy, together with the underlying important molecular mechanisms, in purpose of further exploring more effective use of citrus peel flavonoids.

Tangeretin, a citrus pentamethoxyflavone, exerts cytostatic effect via p53/p21 up-regulation and suppresses metastasis in 7,12-dimethylbenz(α)anthracene-induced rat mammary carcinoma

Breast cancer is the most commonly diagnosed cancer among women worldwide, which is characterized by unregulated cell growth and metastasis. Many bioactive compounds of plant origin such as tangeretin have been shown to possess potent antioxidant and anticancerous properties. In the present study we have investigated the chemotherapeutic effect of tangeretin against 7,12-dimethylbenz(α)anthracene (DMBA)-induced rat mammary carcinogenesis and studied its underlying mechanism of action. Breast cancer was induced by "air pouch technique" with a single dose of 25mg/kg of DMBA. Tangeretin (50 mg/kg) was administered orally for four weeks. Remarkably, tangeretin treatment controlled the growth of cancer cells which was clearly evidenced by morphological and histological analysis. Also, serum levels of estradiol, progesterone and prolactin; lipid bound sialic acid and total sialic acid and the tissue levels of nitric oxide and protein carbonyls of cancer induced animals were decreased upon tangeretin treatment. Staining of breast tissues for nucleolar organizer regions, mast cells, glycoproteins, lipids and collagen showed that tangeretin treatment to breast cancer induced rats significantly reduced tumorigenesis. Oral tangeretin treatment also effectively reduced the tumor cell proliferation markers such as PCNA, COX-2 and Ki-67. Further, tangeretin treatment arrested the cancer cell division at the G1/S phase via p53/p21 up-regulation and inhibited metastasis by suppressing matrix metalloproteinase (MMP)-2, MMP-9 and vascular endothelial growth factor. Taken together, the data provides new evidence on the mechanism of action of tangeretin in breast cancer and hence extends the hypothesis supporting its potential use in chemotherapy.

Tangeretin ameliorates oxidative stress in the renal tissues of rats with experimental breast cancer induced by 7,12-dimethylbenz[a]anthracene

Tangeretin, a citrus polymethoxyflavone, is an antioxidant modulator which has been shown to exhibit a surfeit of pharmacological properties. The present study was hypothesized to explore the therapeutic activity of tangeretin against 7,12-dimethylbenz[a]anthracene (DMBA) induced kidney injury in mammary tumor bearing rats. Recently, we have reported the chemotherapeutic effect of tangeretin in the breast tissue of DMBA induced rats. Breast cancer was induced by "air pouch technique" with a single dose of 25mg/kg of DMBA. Tangeretin (50mg/kg/day) was administered orally for four weeks. The renoprotective nature of tangeretin was assessed by analyzing the markers of oxidative stress, proinflammatory cytokines and antioxidant competence in DMBA induced rats. Tangeretin treatment revealed a significant decline in the levels of lipid peroxides, inflammatory cytokines and markers of DNA damage, and a significant improvement in the levels of enzymatic and non-enzymatic antioxidants in the kidney tissue. Similarly, mRNA, protein and immunohistochemical analysis substantiated that tangeretin treatment notably normalizes the renal expression of Nrf2/Keap1, its downstream regulatory proteins and the inflammatory cytokines in the DMBA induced rats. Histological and ultrastructural observations also evidenced that the treatment with tangeretin effectively protects the kidney from DMBA-mediated oxidative damage, hence, proving its nephroprotective nature.

Evaluation of protective effect of myricetin, a bioflavonoid in dimethyl benzanthracene-induced breast cancer in female Wistar rats

Background:

Breast cancer is one of the most common cancers worldwide. Alarmingly, the incidence of breast cancer is rising rapidly in India.

Aim:

The present research was focused to assess the role of myricetin; a bioflavonoid in 7,12-dimethylbenzanthracene (DMBA)-induced breast cancer in female Wistar rats.

Materials and Methods:

A total of 36 female Wistar rats (total 6 groups, n = 6 per group) 6 - 8 weeks old, weighing 150 gm were used in the study. DMBA was given at the dose of 7.5 mg/kg subcutaneously in the mammary region once a week for 4 consecutive weeks in group 2. Vincristine was given in the dose of 500 μg/kg intraperitonially every week for 4 consecutive weeks in group 3. Myricetin was given orally in a dose of 50, 100, and 200 mg/kg in group 4, 5, and 6 respectively. The statistical significance of the data was determined using one way analysis of variance and Duncan's multiple range test.

Results:

The result showed that myricetin increased the antioxidant levels in plasma, erythrocyte lysate, and breast tissue and was effective in preventing the oxidative damage induced by the carcinogen DMBA. Myricetin 50, 100, and 200 mg/kg/oral for 120 days treated animal resulted comparable results to that of standard vincristine and control groups.

Conclusions:

Myricetin was found to be either equieffective or more effective than vincristine in all the parameters studied. Myricetin proved the capacity of flavonols to act as antioxidant in cells represents a potential treatment in the field of oncology.