Evaluation of pyrogallol-induced cytotoxicity in catalase-mutant escherichia coli and mutagenicity in Salmonella typhimurium

Vanilla from Brazilian Atlantic Forest: In vitro and in silico toxicity assessment and high-resolution metabolomic analysis of Vanilla spp. ethanolic extracts

The natural vanilla market, which generates millions annually, is predominantly dependent on Vanilla planifolia, a species characterized by low genetic variability and susceptibility to pathogens. There is an increasing demand for natural vanilla, prized for its complex, authentic, and superior quality compared to artificial counterparts. Therefore, there is a necessity for innovative production alternatives to ensure a consistent and stable supply of vanilla flavors. In this context, vanilla crop wild relatives (WRs) emerge as promising natural sources of the spice. However, these novel species must undergo toxicity assessments to evaluate potential risks and ensure safety for consumption. This study aimed to assess the non-mutagenic and non-carcinogenic properties of ethanolic extracts from V. bahiana, V. chamissonis, V. cribbiana, and V. planifolia through integrated metabolomic profiling, in vitro toxicity assays, and in silico analyses. The integrated approach of metabolomics, in vitro assays, and in silico analyses has highlighted the need for further safety assessments of Vanilla cribbiana ethanolic extract. While the extracts of V. bahiana, V. chamissonis, and V. planifolia generally demonstrated non-mutagenic properties in the Ames assay, V. cribbiana exhibited mutagenicity at high concentrations (5000 μg/plate) in the TA98 strain without metabolic activation. This finding, coupled with the dose-dependent cytotoxicity observed in WST-1 (Water Soluble Tetrazolium) assays, a colorimetric method that assesses the viability of cells exposed to a test substance, underscores the importance of concentration in the safety evaluation of these extracts. Kaempferol and pyrogallol, identified with higher intensity in V. cribbiana, are potential candidates for in vitro mutagenicity. Although the results are not conclusive, they suggest the safety of these extracts at low concentrations. This study emphasizes the value of an integrated approach in providing a nuanced understanding of the safety profiles of natural products, advocating for cautious use and further research into V. cribbiana mutagenicity.

Rapid and direct spectrophotometric method for kinetics studies and routine assay of peroxidase based on aniline diazo substrates

Peroxidases are ubiquitous enzymes that play an important role in living organisms. Current spectrophotometrically based peroxidase assay methods are based on the production of chromophoric substances at the end of the enzymatic reaction. The ambiguity regarding the formation and identity of the final chromophoric product and its possible reactions with other molecules have raised concerns about the accuracy of these methods. This can be of serious concern in inhibition studies. A novel spectrophotometric assay for peroxidase, based on direct measurement of a soluble aniline diazo substrate, is introduced. In addition to the routine assays, this method can be used in comprehensive kinetics studies. 4-[(4-Sulfophenyl)azo]aniline (λmax = 390 nm, ɛ = 32 880 M(-1) cm(-1) at pH 4.5 to 9) was introduced for routine assay of peroxidase. This compound is commercially available and is indexed as a food dye. Using this method, a detection limit of 0.05 nmol mL(-1) was achieved for peroxidase.

Contact sensitizing potential of pyrogallol and 5-amino-o-cresol in female BALB/c mice

Hair dye components such as pyrogallol and cresol have been shown previously to promote allergic reactions such as rashes, dermal inflammation, irritation and dermatitis. The objective of this study was to determine the contact sensitization potential of pyrogallol (PYR) and 5-amino-o-cresol (AOC) when applied dermally to female BALB/c mice. Measurement of the contact hypersensitivity response was initially accomplished using the local lymph node assay. For PYR, significant increases in the proliferation of lymph node cells were observed at concentrations of 0.5% (w/v) and higher. For AOC, borderline increases, albeit significant, in auricular lymph node cell proliferation were observed at 5% and 10%. Results from the irritancy assay suggested that PYR, but not AOC, was an irritant. To further delineate whether PYR was primarily an irritant or a contact sensitizer, the mouse ear swelling test (MEST) was conducted. A significant increase in mouse ear thickness was observed at 72h following challenge with 0.5% PYR in mice that had been sensitized with 5% PYR. In contrast, no effects were observed in the MEST in mice sensitized and challenged with the highest achievable concentration of AOC (10%). Additional studies examining lymph node subpopulations and CD86 (B7.2) expression by B cells further support the indication that PYR was a sensitizer in BALB/c mice. The results demonstrate that PYR is both a sensitizer and an irritant in female BALB/c mice. However, the contact sensitization potential of AOC is minimal in this strain of mouse.

A core in vitro genotoxicity battery comprising the Ames test plus the in vitro micronucleus test is sufficient to detect rodent carcinogens and in vivo genotoxins

In vitro genotoxicity testing needs to include tests in both bacterial and mammalian cells, and be able to detect gene mutations, chromosomal damage and aneuploidy. This may be achieved by a combination of the Ames test (detects gene mutations) and the in vitro micronucleus test (MNvit), since the latter detects both chromosomal aberrations and aneuploidy. In this paper we therefore present an analysis of an existing database of rodent carcinogens and a new database of in vivo genotoxins in terms of the in vitro genotoxicity tests needed to detect their in vivo activity. Published in vitro data from at least one test system (most were from the Ames test) were available for 557 carcinogens and 405 in vivo genotoxins. Because there are fewer publications on the MNvit than for other mammalian cell tests, and because the concordance between the MNvit and the in vitro chromosomal aberration (CAvit) test is so high for clastogenic activity, positive results in the CAvit test were taken as indicative of a positive result in the MNvit where there were no, or only inadequate data for the latter. Also, because Hprt and Tk loci both detect gene-mutation activity, a positive Hprt test was taken as indicative of a mouse-lymphoma Tk assay (MLA)-positive, where there were no data for the latter. Almost all of the 962 rodent carcinogens and in vivo genotoxins were detected by an in vitro battery comprising Ames+MNvit. An additional 11 carcinogens and six in vivo genotoxins would apparently be detected by the MLA, but many of these had not been tested in the MNvit or CAvit tests. Only four chemicals emerge as potentially being more readily detected in MLA than in Ames+MNvit--benzyl acetate, toluene, morphine and thiabendazole--and none of these are convincing cases to argue for the inclusion of the MLA in addition to Ames+MNvit. Thus, there is no convincing evidence that any genotoxic rodent carcinogens or in vivo genotoxins would remain undetected in an in vitro test battery consisting of Ames+MNvit.