RESUMEN
Background: Some Thai vegetables may enhance the activities of some phase II enzymes and decrease activities of phase I enzymes. Thus, they may possess cancer chemo-preventive potentials. Objective: Determine the anti-clastogenic activity of Thai vegetable, Siamese cassia (SC), against an indirectacting clastogens, cyclophosphamide (CYP), and 7, 12-dimethylbenz(a)anthracene (DMBA). Methods: Male mice were fed either with semi-purified diet, containing 2% or 4% of ground lyophilized SC leaves, for two weeks prior to administration of clastogens. The anti-clastogenicity of SC leaves using the in vivo erythrocyte micronucleus assay in mice was performed. Blood samples were collected and counted for reticulocytes with and without a micronucleus using the fluorescent microscope. Results: Feeding SC leaves at 2% or 4% in the diets reduced the number of micronucleated peripheral reticulocytes (MNRETs) induced by both CYP and DMBA. However, the effect was statistically significant only at 4% in CYPinduced mice. Conclusion: Siamese cassia leaves possess anti-clastogenic activity against clastogens in mice, particularly in a high dose.
RESUMEN
The chemopreventive potential of Rhinacanthus nasutus Kurz. (family Acanthaceae), traditionally used in Thai folk medicine for cancer treatment, on 7, 12-Dimethylbenz[a] anthracene (DMBA)-induced mammary gland carcinogenesis in female Sprague-Dawley rats was investigated. Seventy-five rats were randomly divided into seven groups consisting of one control group (15 animals) and six treated groups (10 animals for each group). The control group received 0.3% carboxymethylcellulose in normal saline and each treated group received the aqueous extracts of roots and stems (500 mg/kg body weight/day), chloroform extract and rhinacanthin C from roots (25 and 50 mg/kg body weight/day) intragastrically everyday two weeks prior to the administration of a single oral dose of DMBA (30 mg/kg body weight) in corn oil and continuously for 9 weeks. Rats were weighed and monitored twice weekly for tumor development after DMBA administration. At the end of experiment, all rats were sacrificed and the tumor volume, number of tumor per rat, tumor incidence, histopathological and blood biochemical parameters were evaluated. The results revealed that all extracts and rhinacanthin C isolated from R. nasutus Kurz. at the given doses had no affects in the growth rate between the treated and control groups. Oral administration of aqueous extracts of roots and stems (500 mg/kg/day) and chloroform extract (25 mg/kg/day) in tumor-bearing rats significantly suppressed the growth of mammary gland carcinogenesis (p \< 0.01). Moreover, rhinacanthin C (25 and 50 mg/kg/day) suppressed the tumor growth in dose-dependently (p \< 0.001), whereas the high dose of chloroform extract (50 mg/kg/day) had no effect when compared with the control group. The aqueous extract of roots (500 mg/kg/day), chloroform extract and rhinacanthin C (25 mg/kg/day) markedly reduced the number of tumors per rat at 4.2±0.5, 4.37±0.4 and 4.89±0.2, respectively whereas the aqueous extract of stems and high doses of chloroform extract and rhinacanthin C (50 mg/kg/day) had slightly effect when compared with the control group (7.25±0.8). Likewise, rats receiving the aqueous extract of roots (500 mg/kg/day), chloroform extract and rhinacanthin C (25 mg/kg/day) had lower tumor incidence (72.41%, 60.34% and 75.86%) than the control group (100%). For the biochemical analysis, no significant difference of the biochemical parameters was occurred in rats receiving both of aqueous extracts of roots and stems (500 mg/kg/day). In contrast, the levels of blood urea nitrogen (BUN), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) in rats receiving the high dose of chloroform extract (50 mg/kg/day) were markedly increased. Tumor-bearing rats treated with rhinacanthin C (25 mg/kg/day) also had increasing levels of AST and ALT, but with no significant difference when compared with the control group. Based on these available data, our findings first demonstrate that the aqueous extracts of roots and stems, chloroform extract and rhinacanthin C isolated from roots R. nasutus Kurz. markedly suppress tumor growth, number of tumor per rat and tumor incidence of the mammary gland carcinogenesis in the experimental rats induced by 7, 12-dimethylbenz[a] anthracene (DMBA). Interestingly, aqueous extracts of both roots and stems, traditionally usage forms for the treatment of various cancers, provided significantly effective results. Therefore, Rhinacanthus nasutus Kurz. may be a useful Thai medicinal plant for preventing the mammary carcinogenesis, however, prolonged use and overdoses of chloroform extract and rhinacanthin C should be avoided to prevent hepatoxic and nephrotoxic effects of the drugs.
RESUMEN
A number of vegetables and fruits are known to contain various kinds of chemical possessing chemopreventive potential. Recently, we reported that some Thai vegetables, i.e. ivy gourd leaves (Coccinia grandis (L.) Voigt, Sesbania flowers (Sesbania grandiflora Linn.), lemon grass (Cymbopogon citratus Stapf) and Chinese kale (Brassica alboglabra) contained anti-mutagens against indirect carcinogens/mutagens such as alflatoxin B₁1 (AFB₁) and benz (a) pyrene. The present study aimed at the determination of anti-clastogenic activity of the above vegetables against clastogens/carcinogens i.e. mitomycin C (MMC) and 7, 12-dimethylbenz(a)anthracene (DMBA) using the in vivo mouse erythrocyte micronucleus assay. Mice were fed either with semipurified diet containing various concentrations of ground lyophilized vegetables for 2 weeks prior to administration of MMC and DMBA. Blood samples were collected before and after carcinogens administration and counted for reticulocytes both with micronucleus (micronucleated peripheral reticulocytes, MNRETs) and without micronucleus by using fluorescent microscope. It was found that feeding diets containing 5% and 10 % of ivy gourd leaves significantly decreased the number of MNRETs induced by both MMC and DMBA. Sesbania flowers at 5% and 10% also caused a reduction in the number of MNRETs induced by both MMC and DMBA, however, the difference was significant only at high concentration. On the other hand, lemon grass at 5% and 10% decreased MNRETs induced by both MMC and DMBA. Interestingly however, the effect was statistically significant only at high concentration in DMBA-treated group. Chinese kale at 10% and 20% could not reduce MNRETs. The present study demonstrated that leaves of ivy gourd and flowers of sesbania possessed anticlastogenic activity against both direct and indirect-acting clastogens in the mouse. In addition, lemon grass could inhibit the clastogenicity of only indirect-acting clastogen. While Chinese kale did not inhibit the clastogenicity.