Mass Spectrometric and Spectrofluorometric Studies of the Interaction of Aristolochic Acids with Proteins

Biotransformation and Toxicities of Aristolochic Acids

Environmental and iatrogenic exposures contribute significantly to human diseases, including cancer. The list of known human carcinogens has recently been extended by the addition of aristolochic acids (AAs). AAs occur primarily in Aristolochia herbs, which are used extensively in folk medicines, including Traditional Chinese Medicine. Ingestion of AAs results in chronic renal disease and cancer. Despite importation bans imposed by certain countries, herbal remedies containing AAs are readily available for purchase through the internet. With recent advancements in mass spectrometry, next generation sequencing, and the development of integrated organs-on-chips, our knowledge of cancers associated with AA exposure, and of the mechanisms involved in AA toxicities, has significantly improved. DNA adduction plays a central role in AA-induced cancers; however, significant gaps remain in our knowledge as to how cellular enzymes promote activation of AAs and how the reactive species selectively bind to DNA and kidney proteins. In this review, I describe pathways for AAs biotransformation, adduction, and mutagenesis, emphasizing novel methods and ideas contributing to our present understanding of AA toxicities in humans.

Characterization of the fungitoxic activity on Botrytis cinerea of the aristolochic acids I and II

The fungitoxic effect of aristolochic acids I and II on mycelial growth and conidial germination of Botrytis cinerea was analysed. Aristolochic acid I had a higher effect on mycelial growth of B. cinerea than aristolochic acid II with IC₅₀ value of 18·7 and 57·0 μg ml^-1 , respectively. These compounds did not affect the conidia germination. Also, the effect of both compounds on DNA and plasmatic membrane integrity of B. cinerea was studied. Only aristolochic acid II was able to cause damage to the integrity of the plasmatic membrane. When the fungus was incubated with a mixture of these compounds, degradation of DNA was observed. Finally, biotransformation products were not detected in the culture broth when B. cinerea was incubated in the presence of the aristolochic acids. Studies of structural characteristics that increase the antifungal effect of compounds against B. cinerea will permit to design new molecules to control this phytopathogenic fungus. SIGNIFICANCE AND IMPACT OF THE STUDY: The fungitoxic effect on Botrytis cinerea of aristolochic acids I and II was characterized. The only structural difference among these compounds is a methoxy group at carbon 8. However, despite their structural similarity, the fungitoxic effect of aristolochic acid I was higher than the effect of aristolochic acid II. This result suggests that the methoxy group is important for the fungitoxic activity of these compounds on B. cinerea.