In Vitro Toxicity Assessment of Cortinarius sanguineus Anthraquinone Aglycone Extract.

Biocolourants could be a sustainable option for dyes that require fossil-based chemicals in their synthesis. We studied the in vitro toxicity of anthraquinone aglycone extract obtained from Cortinarius sanguineus fungus and compared it to the toxicity of its two main components, emodin and previously studied dermocybin. Cell viability, cytotoxicity, and oxidative stress responses in HepG2 liver and THP-1 immune cell lines were studied along with skin sensitisation. In addition, genotoxicity was studied with comet assay in HepG2 cells. Cellular viability was determined by MTT, propidium iodide, and lactate dehydrogenase assays, which showed that the highest doses of both the aglycone extract and emodin affected the viability. However, the effect did not occur in all of the used assays. Notably, after both exposures, a dose-dependent increase in oxidative stress factors was observed in both cell lines as measured by MitoSOX and dihydroethidium assays. C. sanguineus extract was not genotoxic in the comet assay. Importantly, both emodin and the extract activated the skin sensitisation pathway in the KeratinoSens assay, suggesting that they can induce allergy in humans. As emodin has shown cytotoxic and skin-sensitising effects, it is possible that the adverse effects caused by the extract are also mediated by it since it is the main component present in the fungus.

Anthraquinone biocolourant dermocybin is metabolized whereas dermorubin is not in in vitro liver fractions and recombinant metabolic enzymes.

Fungal anthraquinones dermocybin and dermorubin are attractive alternatives for synthetic dyes but their metabolism is largely unknown. We conducted a qualitative in vitro study to identify their metabolism using human liver microsomes and cytosol, as well as recombinant human cytochrome P450 (CYP), UDP-glucuronosyltransferase (UGT) and sulfotransferase (SULT) enzymes. Additionally, liver microsomal and cytosolic fractions from rat, mouse and pig were used. Following incubations of the biocolourants with the enzymes in the presence of nicotinamide adenine dinucleotide phosphate, UDP-glucuronic acid, 3'-phosphoadenosine-5'-phosphosulfate (PAPS) or S-adenosyl methionine (SAM) to enable CYP oxidation, glucuronidation, sulfonation or methylation, we observed several oxidation and conjugation metabolites for dermocybin but none for dermorubin. Human CYP1A1, 1A2, 1B1, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, 3A4 and 3A7 catalysed dermocybin oxidation. The formation of dermocybin glucuronides was catalysed by human UGT1A1, 1A3, 1A7, 1A8, 1A9, 1A10 and 2B15. Human SULT1B1, 1C2 and 2A1 sulfonated dermocybin. Dermocybin oxidation was faster than conjugation in human liver microsomes. Species differences were seen in dermocybin glucuronidation between human, rat, mouse and pig. In conclusion, many CYP and conjugation enzymes metabolized dermocybin, whereas dermorubin was not metabolized in human liver fractions in vitro. The results indicate that dermocybin would be metabolized in humans in vivo.

Waterless Dyeing and In Vitro Toxicological Properties of Biocolorants from Cortinarius sanguineus.

As a part of an ongoing interest in identifying environmentally friendly alternatives to synthetic dyes and in using liquid CO2 as a waterless medium for applying the resulting colorants to textiles, our attention turned to yellow-to-red biocolorants produced by Cortinarius sanguineus fungus. The three principal target anthraquinone colorants (emodin, dermocybin, and dermorubin) were isolated from the fungal bodies using a liquid-liquid separation method and characterized using 700 MHz NMR and high-resolution mass spectral analyses. Following structure confirmations, the three colorants were examined for dyeing synthetic polyester (PET) textile fibers in supercritical CO2. We found that all three biocolorants were suitable for dyeing PET fibers using this technology, and our attention then turned to determining their toxicological properties. As emodin has shown mutagenic potential in previous studies, we concentrated our present toxicity studies on dermocybin and dermorubin. Both colorants were non-mutagenic, presented low cellular toxicity, and did not induce skin sensitization. Taken together, our results indicate that dermocybin and dermorubin possess the technical and toxicological properties needed for consideration as synthetic dye alternatives under conditions that are free of wastewater production.