Herbal bioactivation, molecular targets and the toxicity relevance

Contributions of human enzymes in carcinogen metabolism

Considerable support exists for the roles of metabolism in modulating the carcinogenic properties of chemicals. In particular, many of these compounds are pro-carcinogens that require activation to electrophilic forms to exert genotoxic effects. We systematically analyzed the existing literature on the metabolism of carcinogens by human enzymes, which has been developed largely in the past 25 years. The metabolism and especially bioactivation of carcinogens are dominated by cytochrome P450 enzymes (66% of bioactivations). Within this group, six P450s--1A1, 1A2, 1B1, 2A6, 2E1, and 3A4--accounted for 77% of the P450 activation reactions. The roles of these P450s can be compared with those estimated for drug metabolism and should be considered in issues involving enzyme induction, chemoprevention, molecular epidemiology, interindividual variations, and risk assessment.

Toxic effects of Carthamus tinctorius L. (Safflower) extract on mouse spermatogenesis

OBJECTIVE

To evaluate the effects of aqueous extract of Carthamus tinctorius L., also named safflower, on mouse spermatogenesis.

METHODS

Sixteen adult male NMRI mice were used. Experimental group received Carthamus tinctorius L. extract at the dose of 200 mg/kg for 35 consecutive days and control group received only distilled water. Testicular histopathology, morphometric analysis and spermatogenesis assessments were performed for evaluation of the Carthamus tinctorius L. extract effects on testis.

RESULTS

Histopathological criteria such as epithelial vacuolization, sloughing of germ and detachment were significantly decreased in Carthamus tinctorius L. treated mice (p < 0.001). Carthamus tinctorius L. extract induced formation of multinucleated giant cells in the germinal epithelium. Carthamus tinctorius L. extract also caused a significant decrease in seminiferous tubule diameter, seminiferous epithelium height and maturation arrest (p < 0.001).

CONCLUSION

Carthamus tinctorius L. extract has toxic effects on mouse testicular tissue, and recommended to use it with caution if there is a reproductive problem.

Review of current and "omics" methods for assessing the toxicity (genotoxicity, teratogenicity and nephrotoxicity) of herbal medicines and mushrooms

ETHNOPHARMACOLOGICAL RELEVANCE

The increasing use of traditional herbal medicines around the world requires more scientific evidence for their putative harmlessness. To this end, a plethora of methods exist, more or less satisfying. In this post-genome era, recent reviews are however scarce, not only on the use of new "omics" methods (transcriptomics, proteomics, metabonomics) for genotoxicity, teratogenicity, and nephrotoxicity assessment, but also on conventional ones.

METHODS

The present work aims (i) to review conventional methods used to assess genotoxicity, teratogenicity and nephrotoxicity of medicinal plants and mushrooms; (ii) to report recent progress in the use of "omics" technologies in this field; (iii) to underline advantages and limitations of promising methods; and lastly (iv) to suggest ways whereby the genotoxicity, teratogenicity, and nephrotoxicity assessment of traditional herbal medicines could be more predictive.

RESULTS

Literature and safety reports show that structural alerts, in silico and classical in vitro and in vivo predictive methods are often used. The current trend to develop "omics" technologies to assess genotoxicity, teratogenicity and nephrotoxicity is promising but most often relies on methods that are still not standardized and validated.

CONCLUSION

Hence, it is critical that toxicologists in industry, regulatory agencies and academic institutions develop a consensus, based on rigorous methods, about the reliability and interpretation of endpoints. It will also be important to regulate the integration of conventional methods for toxicity assessments with new "omics" technologies.