Effects In Ames Test Research Articles

Pre-clinical in vitro and in vivo safety evaluation of Cimicifuga heracleifolia

The rhizomes of Cimicifuga species, including Cimicifuga heracleifolia (CH), have been widely used as antipyretic, analgesic, and anti-inflammatory agents in oriental countries. However, information regarding its toxicity, especially long-term toxicity and genotoxicity, is limited. Therefore, we performed the subchronic toxicity and genotoxicity assays of the CH extract in accordance with the test guidelines published by the Organization for Economic Cooperation and Development. In a 13-week repeat-dose oral toxicity study, the CH extract did not influence body weight, food/water consumption, mortality, clinical signs, and urinalysis throughout the study. Noteworthy, the CH extract groups exhibited increased liver weights along with serum alanine transaminase activity rise at doses of 667 and 2000 mg/kg in females. No-observed-adverse-effect-level of the CH extract administered orally was concluded to be 2000 mg/kg body weight/day for male rats and 222 mg/kg body weight/day for female rats. The CH extract did not exert a mutagenic or clastogenic effect in Ames test, in vitro chromosome aberration assay and in vivo micronucleus assay. Overall findings of the subchronic toxicity study indicate for the first time that the CH extract may possess hepatotoxic potential in female rats, suggesting that further mechanistic studies should be performed to have more conclusive results on hepatotoxic potential of the CH extract.

Intestinal α-glucosidase inhibitory activity and toxicological evaluation of Nymphaea stellata flowers extract

Aim of the study Nymphaea stellata willd. flowers (NSF) are used as a traditional medicine in India and Nepal to treat diabetic disease. Different works have demonstrated that NSF extract showed antihyperglycemic effect on alloxan-induced diabetic rats. In the present work we evaluated in vitro intestinal α-glucosidase inhibition as the possible mode of action of NSF extract on suppressing postprandial hyperglycemia for curing diabetic mellitus. In addition, NSF extract was studied to assess its possible acute oral toxicity and genotoxicity. Materials and methods Rat intestinal crude enzyme preparation and Caco-2 monolayer were used to evaluate α-glucosidase inhibitory activity of NSF extract. The main α-glucosidase inhibitors were detected by HPLC. For acute toxicity test, NSF extract was administered at doses of 2000, 5000 and 10,000 mg/kg body to three groups of 10 ICR mice each, and then clinical symptoms including mortality, clinical sign and gross findings were observed once a day for 14 days. In Ames test, histidine-dependent auxotrophic mutants of Salmonella typhimurium (strains TA97, TA98, TA100, TA102 and TA1535) were used and incubated in the presence and absence of S9 metabolic activation using NSF extract with concentrations of 150–5000 μg/plate. The chromosome aberration test was conducted with Chinese hamster lung (CHL) cells treated with NSF extract at doses of 150–5000 μg/ml in the presence and absence of S9 metabolic activation. In the in vivo mouse micronucleus assay, 9-week-old male and female ICR mice ( n = 90, 25–30 g) were administered daily by oral gavage at doses of 2.5, 5.0 and 10.0 g/kg body for 1 or 2 days. Bone marrow smears were prepared from each treatment group 24 h after last administration and then polychromatic erythrocytes (PCEs) and normochromatic erythrocytes (NCEs) were identified. Results NSF extract showed potent rat intestinal α-glucosidase inhibitory activity for maltose hydrolysis with ED 50 value of 0.1 mg/ml. In Caco-2 monolayer, α-glucosidase activity for the maltose hydrolysis was down-regulated by NSF extract at a concentration of 0.05 mg/well level, showing 74% inhibition compared to the saline treated control. NSF was rich in phenol contents and the main α-glucosidase inhibitor, 1,2,3,4,6-penta-O-galloyl-β- d-glucose, was identified together with two phenolic compounds of gallic acid and corilagin. In acute toxicity test, NSF extract did not produce any toxic signs or deaths and the LD 50 value of this extract could be greater than 10,000 mg/kg body weight. These results of genotoxicity assessment showed that NSF extract did not cause genotoxic effects in Ames test, in the in vitro chromosomal aberration assay and in the in vivo micronucleus assay. Conclusion The current study shows that the extract from Nymphaea stellata flowers exhibits significant intestinal α-glucosidase inhibitory activity, without showing any acute toxicity or genotoxicity, which may be useful in suppressing postprandial hyperglycemia in diabetics. The results presented here suggest that the use of NSF in folk medicine as a natural antidiabetic treatment could be safe as well as beneficial.

Pharmacological and toxicological studies on anticancer properties of piplartine

Piplartine is a known alkaloid/amide from Piper species with interesting cytotoxic properties. Pharmacological and toxicological studies of the anticancer properties were performed in several biological models. Piplartine presented IC50 values ranging from 1.04 to 3.03µM in tumor cell lines, while in peripheral blood mononuclear cells the IC50 was 45.24µM, suggesting a narrow selectivity for this compound. The structure-activity relationship analysis demonstrated that the presence of the α,β-unsaturated carbonyl moiety of the amide ring is an important structural requirement for cytotoxic activity. Moreover, piplartine treatment induced G2 cell cycle arrest followed by apoptosis in HL-60 cells by the intrinsic pathway. Piplartine treatment also induced DNA strand breaks in V79 cells. Its genotoxic mechanism of action seems to be similar to its cytotoxic activity. No mutagenic effect in Ames test (prokaryotic model) was observed. On the other hand, piplartine was mutagenic and recombinogenic in yeast (eukaryotic model). This can be explained due the differences in physiology between eukaryote and prokaryote DNA topoisomerase II, reflecting a possible interference of piplartine upon this enzyme activity. The genotoxicity was confirmed in vivo with piplartine increasing the micronuclei levels in treated mice. Additionally, the plasma levels of piplartine are compatible with the in vitro cytotoxicity, which leads us to propose that piplartine has in vivo direct cytotoxic properties. In antitumor assay, the combination of piplartine with 5-fluourouracil led to an in vitro and in vivo increasing of the tumor growth inhibition. In addition, hematological analysis showed leukopenia after 5-fluourouracil treatment, which was reversed by the combined use of piplartine. These data suggest that piplartine has a promising anticancer potential.