Jung-Hee Yoon

The toxicity and distribution of iron oxide–zinc oxide core‐shell nanoparticles in C57BL/6 mice after repeated subcutaneous administration

Therapeutic cancer vaccines promote immune responses by delivering tumour‐specific antigens. Recently, we developed iron oxide (Fe3O4)–zinc oxide (ZnO) core‐shell nanoparticles (CSNPs) as carriers for antigen delivery into dendritic cells (DCs), and the CSNPs were injected subcutaneously into C57BL/6 mice to examine the systemic toxicity, tissue distribution and excretion of the CSNPs. The doses injected were 0, 4, 20 and 200 mg kg–1 weekly for 4 weeks. No significant changes were observed after the CSNPs administration with respect to mortality, clinical observations, body weight, food intake, water consumption, urinalysis, haematology, serum biochemistry,and organ weights. A dose‐dependent increase in granulomatous inflammation was observed at the injection site of the CSNP‐treated animals, but no other histopathological lesions in other organs could be attributed to the CSNPs. The Zn concentration, which is an indicator for CSNPs, was not significantly higher in the sampled tissues, urine, or faeces after the CSNP injection. In contrast, the Zn concentration at the subcutaneous skin of the site injected with the CSNPs increased in a dose‐dependent manner, along with a macroscopic deposition of the CSNPs. The CSNP residue at the injection site resulted in a foreign body response with the appearance of macrophage infiltration, but otherwise did not show any systemic distribution or toxicity at up to 200 mg kg–1 during this study. In conclusion, CSNPs could be used as good antigen carriers for DC‐based immunotherapy, although further study is needed to completely clear the residue of the CSNPs at the injection site. Copyright

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.

Exploration and comparison of in vitro eye irritation tests with the ISO standard in vivo rabbit test for the evaluation of the ocular irritancy of contact lenses.

In an effort to explore the use of alternative methods to animal testing for the evaluation of the ocular irritancy of medical devices, we evaluated representative contact lenses with the bovine corneal opacity and permeability test (BCOP) and an in vitro eye irritation test using the three-dimensionally-reconstructed human corneal epithelium (RhCE) models, EpiOcular™ and MCTT HCE™. In addition, we compared the obtained results with the ISO standard in vivo rabbit eye irritation test (ISO10993-10). Along with the positive controls (benzalkonium chloride, BAK, 0.02, 0.2, and 1%), the extracts of 4 representative contact lenses (soft, disposable, hard, and colored lenses) and 2 reference lenses (dye-eluting and BAK-coated lenses) were tested. All the lenses, except for the BAK-coated lens, were determined non-irritants in all test methods, while the positive controls yielded relevant results. More importantly, BCOP, EpiOcular™, and MCTT HCE™ yielded a consistent decision for all the tested samples, with the exception of 0.2% BAK in BCOP, for which no prediction could be made. Overall, all the in vitro tests correlated well with the in vivo rabbit eye irritation test, and furthermore, the combination of in vitro tests as a tiered testing strategy was able to produce results similar to those seen in vivo. These observations suggest that such methods can be used as alternative assays to replace the conventional in vivo test method in the evaluation of the ocular irritancy of ophthalmic medical devices, although further study is necessary.

A comprehensive study on in vitro and in vivo toxicological evaluation of Artemisia capillaris

ABSTRACT Artemisia capillaris (AC) has been used as an alternative therapy in obesity, atopic dermatitis, and liver diseases through several biological activity including anti‐steatotic, antioxidant, and anti‐inflammatory activities. Despite its ethnomedicinal benefits, no sufficient background information is available about the long‐term safety and genotoxicity of the AC extract. Therefore, the present study was carried out to investigate the 13‐week subchronic toxicity and genotoxicity of the AC extract according to the test guidelines published by the Organization for Economic Cooperation and Development. In the 13‐week toxicity study using doses of 25, 74, 222, 667, and 2000 mg/kg body weight, oral administration of the AC extract in male and female rats did not result in any significant adverse effects in food/water consumption, body weight, mortality, hematology, serum biochemistry, organ weight and histopathology. Accordingly, the no‐observed‐adverse‐effect level in rats of both genders was established for the AC extract at 2000 mg/kg/day, the highest dose level tested. In addition, the AC extract was not genotoxic in a battery of tests including Ames test, in vitro chromosome aberration assay and in vivo micronucleus assay. In conclusion, we demonstrated that the AC extract is considered as a safe traditional medicine for human consumption. HIGHLIGHTSWe conducted subchronic toxicity and genotoxicity studies of AC extract.In subchronic study, NOAEL was determined to be greater than 2000 mg/kg/day in rats.In genotoxicity studies, AC extract was not clastogenic and mutagenic.

Enzymatic extract from Ecklonia cava : Acute and subchronic oral toxicity and genotoxicity studies

ABSTRACT Ecklonia cava (EC) is known to have antioxidant, anti‐inflammatory, antidiabetic, and anticancer properties. Despite its wide use and beneficial properties, comprehensive toxicological information regarding EC extract is currently limited. Therefore, the purpose of this study was to investigate acute toxicity, subchronic toxicity, and genotoxicity of enzymatic EC extract according to test guidelines published by Organization for Economic Cooperation and Development. The acute oral LD50 values of this EC extract administered to rats and dogs were estimated to be more than 3000 mg/kg BW. In an oral 13‐week toxicity study, changes in body weights of rats exposed to the EC extract up to 3000 mg/kg BW were found to be normal. In addition, repeated doses of EC extract failed to influence any systematic parameters of treatment‐related toxic symptoms such as food/water consumption, mortality, urinalysis, hematology, serum biochemistry, organ weight, or histopathology. These results indicated that the no‐observed‐adverse‐effect level for the EC extract was 3000 mg/kg/day for male and female rats. Data obtained from Ames test, chromosome aberration assay, and micronucleus assay indicated that EC extract was not mutagenic or clastogenic. Taken together, these results support the safety of enzymatic EC extract as a potential therapeutic for human consumption against various diseases. HighlightsWe conducted acute, subchronic toxicity and genotoxicity studies of EC extract.In acute toxicity study, LD50 were higher than 3000 mg/kg in rats and beagle dogs.In subchronic study, NOAEL was determined to be greater than 3000 mg/kg/day in rats.In genotoxicity studies, EC extract was not clastogenic and mutagenic.

In vitro and in vivo safety studies of cinnamon extract ( Cinnamomum cassia ) on general and genetic toxicology

ABSTRACT Cinnamomum cassia has been widely used as a natural product to treat diseases in Asia due to its diverse pharmacological functions including anti‐inflammatory, anti‐oxidant, anti‐microbial, anti‐diabetic, and anti‐tumor effects. Despite its ethnomedicinal benefits, little information regarding its toxicity is currently available. The aim of this study was to evaluate its potential long‐term toxicity and genotoxicity in compliance with test guidelines of the Organization for Economic Cooperation and Development. A 13‐week repeat‐dose oral toxicity study revealed that body weights of rats were normal after receiving cinnamon extract at up to 2000 mg/kg. High‐dose intake of cinnamon extract (2000 mg/kg) showed potential nephrotoxicity and hepatotoxicity to both males and females as evidenced by obvious increases of kidney/liver weight along with a small but statistically elevation of total cholesterol level. Overall findings from genetic toxicity testing battery including Ames test, in vitro mammalian cell micronucleus assay, and in vivo bone marrow micronucleus assay indicated that cinnamon extract was not mutagenic or clastogenic. In conclusion, cinnamon extract may possess potential nephrotoxicity and hepatotoxicity at dose higher than its recommended daily safe dose. Further study is needed to clarify the mechanism involved in its induction of liver and kidney injury. HighlightsWe conducted acute, subchronic toxicity and genotoxicity studies of cinnamon extract.Liver weight was increased by high‐dose (2000 mg/kg) of cinnamon extract.High‐dose (2000 mg/kg) of cinnamon extract induced kidney weight increase.In genotoxicity studies, cinnamon extract was not clastogenic and mutagenic.

Absence of subchronic oral toxicity and genotoxicity of rice koji with Aspergillus terreus

&NA; Koji products have been considered as an effective fermented food consumed in East Asia with many health benefits. Particularly, rice koji with Aspergillus terreus (RAT) has been reported to be able to prevent hyperlipidemia and hepatic steatosis through regulating cholesterol synthesis. Despite its biological activities, there is a lack of comprehensive information to give an assurance of its safety. Therefore, the objective of this study was to perform a series of toxicological studies (repeated dose oral toxicity and genotoxicity) according to test guidelines published by the Organization for Economic Cooperation and Development. Along with acute toxicity study using rats and beagle dogs, a 13‐week toxicity study revealed no clear RAT‐related toxic changes, including body weight, mortality, hematology, serum biochemistry, organ weight, and histopathology after oral administration at doses of 500, 1000, and 2000 mg/kg BW. The no‐observed‐adverse‐effect level of RAT was considered to be more than 2000 mg/kg BW/day in rats of both genders. In addition, potential genotoxicity was evaluated using a standard battery of tests (Ames test, chromosome aberration assay, and micronucleus assay) which revealed that RAT showed no genotoxicity. Accordingly, these results suggest that RAT is a safe and non‐toxic functional food for human consumption at proper dose. HighlightsWe conducted acute, subchronic toxicity and genotoxicity studies of RAT.In acute toxicity study, LD50 were higher than 2000 mg/kg in rats and beagle dogs.In subchronic toxicity study, NOAEL was greater than 2000 mg/kg/day in rats.In genotoxicity studies, RAT was not clastogenic and mutagenic.