Evaluation of the genotoxic potential of three phenyltetrahydropyridinyl butylazole-derived sigma-receptor ligand drug candidates

Phytochemical composition and in vitro safety evaluation of Ziziphora clinopodioides Lam. ethanolic extract: Cytotoxicity, genotoxicity and mutagenicity assessment

ETHNOPHARMACOLOGICAL RELEVANCE

The application of the herb Ziziphora clinopodioides Lam. in folk medicine and as a food additive has been recommended due to its many claimed bioactivities. Regardless of the plant benefits, its safety considerations are largely unknown.

AIM OF THE STUDY

The aim of the present research was to determine the chemical compositions and cytotoxicity, genotoxicity, and mutagenicity potentials of the ethanolic extract of Ziziphora clinopdioides Lam. (EEZC).

MATERIALS AND METHODS

GC-MS and LC-MS analysis were used for chemical composition determination. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and trypan blue exclusion dye assays were used for cytotoxicity and the Comet assay was employed for genotoxicity assessment on human blood lymphocytes. Also, the Ames Salmonella/microsome test was carried out for the evaluation of mutagenicity.

RESULTS

Pulegone was the main component of the n-hexane fraction. Different phenolic acids and flavonoids were detected by LC-MS. The cytotoxicity study indicated a conspicuous decline in human lymphocyte viability ranging from 52% to 100% as showed by the MTT assay and 67% up to 100% by the trypan blue assay, at 1 and 10 mg/mL, respectively. The Comet assay results revealed a dose dependent genotoxicity, in so much as 90% and 98% of the cells were screened as damaged at concentrations of 5 and 10 mg/mL, respectively. An incidence rate of 8% and 13% of grade 4 damage was observed at 5 and 10 mg/mL, respectively. Additionally, the DNA damage index (DI) was elevated dose-dependently by a rising concentration of the extract, wherein the DI at 10 mg/mL concentration was 2.22, which was 22 times greater than that of negative control, and even more than positive control. The Ames test exhibited no signs of mutagenicity for neither Salmonella typhimurium TA98 nor TA100 strains, accompanied or unaccompanied by S9 metabolic activation.

CONCLUSION

Results indicated a dose-dependent cytotoxicity and genotoxicity potential of the EEZC on human lymphocytes, suggesting that this plant should be used with caution by consumers, even in the food and pharmaceutical industries. Since the plant usage in daily life continues to increase due to its ever growing phytotherapical and phytonutritional properties, it may pose a health risk by its high concentration's uptake. Although no mutagenicity of this extract was observed in this study, further research is recommended to clarify the mutagenic risks of this herb.

Evaluation of toxic, cytotoxic and genotoxic effects of phytol and its nanoemulsion

Phytol (PYT) is a diterpenoid having important biological activity. However, it is a water non-soluble compound. This study aims to prepare PYT nanoemulsion (PNE) and evaluation of toxic, cytotoxic and genotoxic activities of PYT and PNE. For this, the PNE was prepared by the phase inversion method. The cytotoxicity test was performed in Artemia salina, while toxicity, cytotoxicity and genotoxicity in Allium cepa at concentrations of 2, 4, 8 and 16 mM. Potassium dichromate and copper sulfate were used as positive controls for the tests of A. salina and A. cepa, respectively. In addition, an adaptation response was detected in A. cepa by using the comet assay. The results suggest that both PYT and PNE exhibited toxic and cytotoxic effects at 4-16 mM in either test system, while genotoxicity at 2-16 mM in A. cepa. PNE exhibited more toxic, cytotoxic and genotoxic effects at 8 and 16 mM than the PYT. However, both PYT and PNE at 2 and 4 mM decreased the index and frequency of damage in A. cepa after 48 and 72 h, suggesting a possible adaptation response or DNA damage preventing capacity. Nanoemulsified PYT (PNE) may readily cross the biological membranes with an increase in bioavailability and produce more toxic, cytotoxic and genotoxic effects in the used test systems.

Therapeutic Potential of Essential Oils Focusing on Diterpenes

Among all plant derivates, essential oils (EOs) have gained the attention of many scientists. Diterpenes, a family of components present in some EO, are becoming a milestone in the EOs world. The goal of this review is to describe a scenario of diterpenes taking into health-consumption deportment. Previous studies revealed that diterpenes have antioxidant, antimicrobial, antiviral, antiprotozoal, cytotoxic, anticancer, antigenotoxic, antimutagenic, chemopreventive, antiinflammatory, antinociceptive, immunostimulatory, organoprotective, antidiabetic, lipid-lowering, antiallergic, antiplatelet, antithrombotic, and antitoxin activities. In conclusion, diterpenes may be an immense featuring concern in pharmaceutical consumption from a drug discovery point of view. Copyright © 2016 John Wiley & Sons, Ltd.

In vitro toxicological evaluation of essential oils and their main compounds used in active food packaging: A review

Essential oils (EOs) and their main constituent compounds have been extensively investigated due to their application in the food industry for improving the shelf life of perishable products. Although they are still not available for use in food packaging in the market in Europe, considerable research in this field has been carried out recently. The safety of these EOs should be guaranteed before being commercialized. The aim of this work was to review the scientific publications, with a primary focus on the last 10 years, with respect to different in vitro toxicological aspects, mainly focussed on mutagenicity/genotoxicity. In general, fewer genotoxic studies have been reported on EOs in comparison to their main components, and most of them did not show mutagenic activity. However, more studies are needed in this field since the guidelines of the European Food Safety Authority have not always been followed accurately. The mutagenic/genotoxic activities of these substances have been related to metabolic activation. Therefore, in vivo tests are required to confirm the absence of genotoxic effects. Considering the great variability of the EOs and their main compounds, a case-by-case evaluation is needed to assure their safe use in food packaging.

Induction of hypothermic conditions associated with increased micronuclei formation in sigma-1 receptor knockout mice after administration of the antipsychotic compound E-5842

The antipsychotic sigma-1 (sigma(1)) receptor ligand E-5842 has been shown to increase micronucleated polychromatic erythrocyte (MNPCE) frequency in mouse bone marrow secondary to compound-induced hypothermia. Interaction with sigma(1) receptor has been considered a plausible contributing factor for E-5842-induced hypothermia, raising concern for a possible class effect of sigma receptor ligands in the mouse micronucleus (MN) test. We assessed the potential of E-5842 (200 mg/kg, oral) to produce hypothermic conditions associated with increased micronuclei formation in sigma(1) receptor knockout (sigma(1)R-KO) and wild type (WT) mice. After administration, animal's rectal temperature was recorded and peripheral blood and bone marrow samples were obtained (48 hr) and assessed for induction of micronucleated reticulocytes (MNRET) and MNPCE, respectively. E-5842 administration produced marked hypothermia both in sigma(1)R-KO and WT mice. Maximum decreases from preadministration temperature were 12.2 and 13.5 degrees C in sigma(1)R-KO and WT mice, respectively. Temperature returned to normal approximately 32 hr after administration. Bone marrow examination revealed a statistical significant increase (P < 0.05) in MNPCE frequency both in sigma(1)R-KO and WT animals. Examination of peripheral blood samples showed a slight, although nonstatistical significant, increase in MNRET frequency in sigma(1)R-KO mice. No similar effect was observed among WT animals. The results obtained after E-5842 administration to sigma(1)R-KO mice indicate that induction of hypothermic conditions associated with increased MNPCE formation is not mediated by compound interaction with sigma(1) receptor, ruling out concern for a possible class effect of similar high affinity sigma(1) receptor ligands in the mouse MN test.