RESUMO
Polyporoid fungi represent a vast source of bioactive compounds with potential pharmacological applications. The importance of polyporoid fungi in traditional Chinese medicine has led to an extensive use of some species of Ganoderma for promoting health and longevity because their consumption is associated with several bioactivities. Nevertheless, bioactivity of some other members of the Polyporaceae family has also been reported. This work reports the antiproliferative and antibacterial activity of crude extracts obtained from fruiting bodies of polypore fungi collected from the central region of Veracruz, Mexico, aimed at understanding the diversity of polypore species with potential pharmacological applications. 29 collections were identified macro- and microscopically in 19 species of polyporoid fungi, belonging to 13 genera. The antiproliferative activity screening of extracts against solid tumor cell lines (A549, SW1573, HeLa, HBL-100, T-47D, WiDr) allow us to identify four extracts with strong bioactivity [half-maximal growth inhibition (GI50) ≤ 50 µg/mL]. After this, a phylogenetic analysis of DNA sequences from the ITS region obtained from bioactive specimens allowed us to identify three extracts as Pycnoporus sanguineus (GI50 = ≤ 10 µg/mL) and the fourth bioactive extract as Ganoderma oerstedii (GI50 = < 50 µg/mL. Likewise, extracts from P. sanguineus showed mild or moderate antibacterial activity against Escherichia coli, Staphylococcus aureus and Xanthomonas albilineas. Bioprospecting studies of polyporoid fungi add to the knowledge of the diversity of macrofungi in Mexico and allow us to select one of the bioactive P. sanguineus to continue the pursuit of bioactive compounds through mycochemical studies.
Assuntos
Antibacterianos , Filogenia , México , Humanos , Antibacterianos/farmacologia , Antibacterianos/química , Antibacterianos/isolamento & purificação , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Antineoplásicos/farmacologia , Antineoplásicos/química , Polyporaceae/química , Polyporaceae/classificação , Carpóforos/química , Testes de Sensibilidade MicrobianaRESUMO
Every year, more than 500,000 new cases of cervical cancer are reported, making it the fourth leading cause of cancer globally. Although human papillomavirus (HPV) vaccines show promise as a protective measure, HPV-related cancers remain a public health problem since the vaccines, which are only specific to certain viral types, are unavailable for mass distribution. Furthermore, the effects of toxicity following ionizing radiation therapy have reoriented views toward the search for radiosensitizers that can reduce toxicity as a consequence of decreased radiation doses. Here, we isolated ergosterol peroxide (EP) from Pleurotus ostreatus and purified it to test its potential effects in vitro. We thus observed that a gradual increase in EP dose correlates with a loss of viability in HeLa and CaSki cervical cell lines. Dose/response curves were constructed using cervical cancer cell lines, as well as normal human peripheral blood mononuclear cells. The selectivity of EP in human lymphocytes and cervical cancer cell lines was tested, and no toxicity was found in normal cells. A combination of treatments revealed a radiosensitizer effect in HeLa cells, when measuring the exposure to EP followed by irradiation with 137Cs. Our findings suggest that EP may be effective as a radiosensitizer in treating cervical cancer.
Assuntos
Ergosterol/análogos & derivados , Extratos Vegetais/farmacologia , Pleurotus/química , Radiossensibilizantes/farmacologia , Neoplasias do Colo do Útero/radioterapia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Ergosterol/farmacologia , Feminino , Humanos , Tolerância a Radiação , Neoplasias do Colo do Útero/fisiopatologiaRESUMO
Consumption of antioxidant supplements is associated to prevention of several diseases. However, recent studies suggest that antioxidants, besides scavenge free radicals could lead development of tumors. Due to conflicting reports on the antioxidant benefits, the capacity to photosensitize the generation of singlet oxygen of seven natural antioxidants was evaluated through photo-oxidation of ergosterol which proved to be an efficient method of indirect detection of singlet oxygen. Our results showed that curcumin, resveratrol and quercetin have pro-oxidant activity due they act as photosensitizers in generation of singlet oxygen. In addition, we observed that genistein, naringenin, ß-carotene and gallic acid besides their antioxidant activity against ROS radicals, are capable of quenching ROS non-radicals as singlet oxygen. Finally, our results allow us to propose a new approach in classification of natural antioxidants scavengers of free radicals, based on their activity as quenchers of singlet oxygen or as photosensitizers in singlet oxygen generation.