Genotoxicity testing of sodium formononetin-3′-sulphonate (Sul-F) by assessing bacterial reverse mutation, chromosomal aberrations and micronucleus tests

Acute, subchronic toxicity and genotoxicity studies of JointAlive, a traditional Chinese medicine formulation for knee osteoarthritis

AIM

In vivo and in vitro toxicity tests of JointAlive® were studied in animal models to support the safe use of JointAlive® as a drug for knee osteoarthritis treatment.

METHODS

The acute toxicity study in Sprague Dawley (SD) rats was conducted at a 20 g/kg bw/day dose of JointAlive®. For 13-week subchronic toxicity tests, SD rats were orally dosed daily with 0.5, 1.5 and 5 g/kg bw/day of JointAlive®. To assess the potential genotoxicity, Ames test, cellular chromosome aberration and mouse micronucleus test in vivo were carried out.

RESULTS

Based on a lack of notable findings other than histopathology finding of co-incidental prostate inflammation at the high dose, the "No Observed Adverse Effect Level (NOAEL)" of JointAlive® was concluded as 5 g/kg bw/day in males and females. Results also indicated that JointAlive® has no risk of genotoxicity.

CONCLUSIONS

General toxicity and genotoxicity studies empirically demonstrated that JointAlive® poses a low risk of potential health risks, providing safety supports for the application of JointAlive® as a potential drug candidate to treat knee osteoarthritis.

A study of D-allulose-associated reproductive toxicity in rats

In this study, we assessed whether D-allulose was associated with reproductive toxicity in rats, assessing reproduction and offspring growth following gavage of parents with 0, 500, 1000, and 2000 mg/kg of this compound. Specifically, female rats were continuously dose from 2 weeks prior to mating until day 21 of lactation, while males were dose for the 10 weeks before mating. We did not observe any direct toxicity or mortality upon D-allulose administration, with no changes in body weight or eating behavior between study and control groups. We also did not observe any significant alterations in precoital time, copulation index, fertility index (male), or pregnancy index (male) between groups. Relative to controls, there was also no effect of D-allulose treatment on pregnancy rates, implantation, pregnancy length, gender ratios, viability indexes, lactation indexes, prenatal death rates, or number of live young at time of birth. Organ weights and indexes were also comparable between groups at time of sacrifice, and treatment was not linked to any obvious manifestations upon necropsy or histopathological examination. In the F1 offspring, the body weights of pups born to parents administered D-allulose (2000, 1000, and 500 mg/kg) were slightly higher on days 1-9 postnatally relative to controls (p < 0.05), however after day 9 these effects were no longer evident. Together, these results indicate a no-observed-adverse-effect level (NOAEL) of D-allulose of 2000 mg/kg, the highest dose tested, in parental animals and their offspring.

Acute toxicity and genotoxicity evaluations of Nattokinase, a promising agent for cardiovascular diseases prevention

Cardiovascular diseases (CVDs) are the leading cause of death in the world; however, current agents for CVDs prevention are still limited. Owing to the serious bleeding risk of Aspirin, FDA recently recommended against it from preventing first heart attacks. Nattokinase (NK), a serine protease possessing many key beneficial effects on cardiovascular system, is being pursued as a promising alternative agent. In light of this, the safety profile of NK, in particular its potential genotoxicity, need to be characterized. The present study is therefore aimed to evaluate the toxicological profile of NK. To assess acute safety, mice were orally administrated with NK at its maximum concentration and the maximum feeding volume twice in a single day, no mortality or toxicological signs were observed. Hence, the maximum daily tolerant dose of NK in mice is up to 480000 FU/kg, which is 1000 times more compared to the recommended daily dose for human. In the genotoxicity studies, NK showed no mutagenic activity as tested by both Ames test and in vivo micronucleus assay. Moreover, NK demonstrated no evidence of potential to induce chromosome aberrations in CHL cells. These results indicate that there is no safety concern for NK in the present preclinical safety studies, supporting the safety of NK as an agent for CVDs prevention.

Application of the in vivo Pig-a gene mutation assay to test the potential genotoxicity of p-phenylenediamine

Currently, it remains controversial whether p-phenylenediamine (PPD) is genotoxic. In this study, we evaluated the potential genotoxicity of PPD using the newly-developed Pig-a gene mutation assay. The results of three classical genetic toxicity tests (bacterial reverse mutation assay, mammalian cell chromosomal aberration test, and mammalian erythrocyte micronucleus test) are all positive, suggesting that PPD is potentially genotoxic. In Pig-a assay, Sprague-Dawley rats are orally administered with PPD for 28 consecutive days at three doses (12.5, 25, and 50 mg/kg/day). Our result shows that PPD (25 and 50 mg/kg/day) dose-dependently increases RET^CD59- value over controls on Day 8. RET^CD59- keeps increasing to the maximum on Day 15 and then decreases until Day 29. PPD also dose-dependently increase RBC^CD59- value on Day 15, which keeps elevating until Day 29. The time-course of RET^CD59- and RBC^CD59- induced by PPD are similar with that induced by N-ethyl-N-nitrosourea (ENU) treatment for 3 days. Our data suggests that PPD has potential genotoxic effects, and the Pig-a assay is sensitive to assess mutagenicity. However, further investigation of the changes of RET^CD59- and RBC^CD59- induced by hair dyes containing PPD should be detected by Pig-a assay in occupational exposure population to confirm the safety of PPD usage.

Heated naringin mitigate the genotoxicity effect of Mitomycin C in BALB/c mice through enhancing the antioxidant status

A major problem with cancer chemotherapy is its severe toxic effects on non-target tissues. Assessment of natural products for their protective effect against anticancer drugs induced toxicity is gaining importance in cancer biology. The aim of the present study was to evaluate the effect of native and thermal treated naringin on the protective effect against mitomycin C (MMC) induced genotoxicity. The genotoxicity in liver kidney and brain cells isolated from Balb/C mice were evaluated by performing the comet assay. Antioxidant and lipid peroxidation assays were carried out to understand the protective effects of these compounds. The comet assay showed that heated and native naringin were not genotoxic at the tested dose (40 mg/kg b.w) on liver, kidney and brain cells. A significant decrease in DNA damages was observed, at the tested doses (20 mg/kg b.w and 40 mg/kg b.w) suggesting a protective role of these molecules against the genotoxicity induced by mitomycin C on liver, kidney and brain cells. Moreover, administration of MMC (6 mg/kg b.w.) altered the activities of glutathione peroxidase and superoxide dismutase accompanied by a significant increase of lipid peroxidation. Pretreatment of mouse with heated and native naringin before MMC administration significantly raised the glutathione peroxidase and superoxide dismutase activities followed by a reduced MMC-induced lipid peroxidation. Our study demonstrated that heat treatment of naringin preserve activities of native naringin. The genoprotective properties of heated and native naringin against MMC could be attributed to its antioxidant activities and its inhibitory effect on lipid peroxidation.