Tyrosinase inhibitors and insecticidal materials produced by Burkholderia cepacia using squid pen as the sole carbon and nitrogen source

[[abstract]]Reports of tyrosinase inhibitors from microorganisms are rare. A tyrosinase inhibitor- and insecticidal materials-producing bacterium, strain TKU026, was isolated from Taiwanese soil and identified as Burkholderia cepacia. Among the tested chitin-containing materials, squid pen best enhanced the production of tyrosinase inhibitors and insecticidal materials. The tyrosinase inhibitory activity (5000 U/mL) and insecticidal activity (81%) against Drosophila larvae was maximised after cultivation on 1% squid-pen containing medium for three days. The tyrosinase inhibitory activity persisted even when the culture was treated with acidic or alkaline conditions of pH 3 or 11. The activities of both tyrosinase inhibitors and insecticide remained at 100%, even after treatment at 100℃ for 30 min. The culture supernatant after three days of cultivation also showed antifungal activity against Aspergillus fumigatus and Fusarium oxysporum with maximal activities of 100% and 80%, respectively, but no antibacterial activity against Escherichia coli was observed. The tyrosinase inhibitors were assumed to be polyphenolic compounds according to the results of chromatography.[[notice]]補正完畢[[journaltype]]國外[[incitationindex]]SCI[[booktype]]紙本[[booktype]]電子版[[countrycodes]]NL

Tyrosinase inhibitory activity of supernatant and semi-purified extracts from squid pen fermented with Burkholderia cepacia TKU025

[[abstract]]Reports of tyrosinase inhibitors from microorganisms are rare. The tyrosinase inhibitory activity was found from the culture supernatant of Burkholderia cepacia TKU025 with 1 % squid pen as the sole carbon/nitrogen source. The fourth-day supernatant showed the strongest tyrosinase inhibitory activity (500 U/ml) and the highest total phenolic content (789 μg/ml GAE). The supernatant was further purified by liquidâliquid partition, and it was found that the methanol extract exhibited the lowest IC50 value of 2 μg/ml in the tyrosinase inhibitory activity assay and was compared with the positive control kojic acid and vitamin C. Significant associations between the tyrosinase inhibitory potency and the total phenolic content were found for the supernatant, extract, and fractions. The tyrosinase inhibitory activity persisted even when it was treated with acidic or alkaline conditions of pH 2 or 12. The tyrosinase inhibitory activity remained at 100 %, even after treatment at 100 °C for 60 min. The tyrosinase inhibitor also showed antimicrobial activity against Escherichia coli, Bacillus cereus, Aspergillus fumigatus, and Fusarium oxysporum.[[booktype]]紙本[[booktype]]電子