The culture filtrate of Lentinula edodes shows potent antimicrobial activity against the plant pathogenic bacteria Ralstonia solanacearum. Bioassay-guided fractionation was conducted using Diaion H...

Yeast biosurfactants are important biotechnological products in the food industry, and they have medical and cosmeceutical applications owing to their specific modes of action, low toxicity, and applicability. Thus, we have isolated and examined biosurfactant-producing yeast for various industrial and medical applications. A rapid and simple method was developed to screen biosurfactant-producing yeasts for high production of eco-friendly biosurfactants. Using this method, several potential niches of biosurfactant-producing yeasts, such as wild flowers, were investigated. We successfully selected a yeast strain, L3-GPY, with potent surfactant activity from a tiger lily, Lilium lancifolium Thunb. Here, we report the first identification of strain L3-GPY as the black yeast Aureobasidium pullulans. In addition, we isolated a new low-surface-tension chemical, designated glycerol-liamocin, from the culture supernatant of strain L3-GPY through consecutive chromatography steps, involving an ODS column, solvent partition, silica gel, Sephadex LH-20, and an ODS Sep-Pak cartridge column. The chemical structure of glycerol-liamocin, determined by mass spectrometry and nuclear magnetic resonance spectroscopy, indicates that it is a novel compound with the molecular formula C₃₃H₆₂O₁₂. Furthermore, glycerol-liamocin exhibited potent biosurfactant activity (31 mN/m). These results suggest that glycerol-liamocin is a potential novel biosurfactantfor use in various industrial applications.

Breast cancer stem cells (BCSCs) are responsible for tumor chemoresistance and recurrence. Targeting CSCs using natural compounds is a novel approach for cancer therapy. A CSC-inhibiting compound was purified from citrus extracts using silica gel, gel filtration and high-pressure liquid chromatography. The purified compound was identified as tangeretin by using nuclear magnetic resonance (NMR). Tangeretin inhibited cell proliferation, CSC formation and tumor growth, and modestly induced apoptosis in CSCs. The frequency of a subpopulation with a CSC phenotype (CD44⁺/CD24⁻) was reduced by tangeretin. Tangeretin reduced the total level and phosphorylated nuclear level of signal transducer and activator of transcription 3 (Stat3). Our results in this study show that tangeretin inhibits the Stat3 signaling pathway and induces CSC death, indicating that tangeretin may be a potential natural compound that targets breast cancer cells and CSCs.

Daldinan A, a novel isoindolinone antioxidant from the ascomycete Daldinia concentrica

Cancer stem cells (CSCs) are drug-resistant and radiation-resistant cancer cells that are responsible for tumor progression and maintenance, cancer recurrence, and metastasis. Targeting breast CSCs with phytochemicals is a new paradigm for cancer prevention and treatment. In this study, activity-guided fractionation from mammosphere formation inhibition assays, repeated chromatographic preparations over silica gel, preparatory thin layer chromatography, and HPLC using aronia extracts led to the isolation of one compound. Using ¹H and ¹³C 2-dimensional nuclear magnetic resonance (NMR) as well as electrospray ionization (ESI) mass spectrometry, the isolated compound was identified as 3-O-p-coumaroyltormentic acid. This compound inhibits breast cancer cell proliferation and mammosphere formation in a dose-dependent manner and reduces the CD44^high/CD24^low subpopulation and aldehyde dehydrogenase (ALDH)-expressing cell population as well as the expression of the self-renewal-related genes CD44, SOX2, and OCT4. 3-O-p-Coumaroyltormentic acid preferentially reduced the protein levels of c-Myc, which is a CSC survival factor, by inducing c-Myc degradation. These findings indicate the novel utilization of 3-O-p-coumaroyltormentic acid for breast cancer therapy via disruption of c-Myc protein, which is a CSC survival factor.