Docosahexaenoic acid inhibits the proliferation of Kras/TP53 double mutant pancreatic ductal adenocarcinoma cells through modulation of glutathione level and suppression of nucleotide synthesis.

The treatment of cancer cells obtained by blocking cellular metabolism has received a lot of attention recently. Previous studies have demonstrated that Kras mutation-mediated abnormal glucose metabolism would lead to an aberrant cell proliferation in human pancreatic ductal adenocarcinoma (PDAC) cells. Previous literature has suggested that consumption of fish oil is associated with lower risk of pancreatic cancer. In this study, we investigated the anti-cancer effects of docosahexaenoic acid (DHA) in human PDAC cells in vitro and in vivo. Omega-3 polyunsaturated fatty acids (PUFAs) such as DHA and eicosapentaenoic acid (EPA) significantly inhibited the proliferation of human PDAC cells. The actions of DHA were evaluated through an induction of cell cycle arrest at G1 phase and noticed a decreased expression of cyclin A, cyclin E and cyclin B proteins in HPAF-II cells. Moreover, it was found that co-treatment of DHA and gemcitabine (GEM) effectively induced oxidative stress and cell death in HPAF-II cells. Interestingly, DHA leads to an increased oxidative glutathione /reduced glutathione (GSSG/GSH) ratio and induced cell apoptosis in HPAF-II cells. The findings in the study showed that supplementation of GSH or N-Acetyl Cysteine (NAC) could reverse DHA-mediated cell death in HPAF-II cells. Additionally, DHA significantly increased cellular level of cysteine, cellular NADP/NADPH ratio and the expression of cystathionase (CTH) and SLCA11/xCT antiporter proteins in HPAF-II cells. The action of DHA was, in part, associated with the inactivation of STAT3 cascade in HPAF-II cells. Treatment with xCT inhibitors, such as erastin or sulfasalazine (SSZ), inhibited the cell survival ability in DHA-treated HPAF-II cells. DHA also inhibited nucleotide synthesis in HPAF-II cells. It was demonstrated in a mouse-xenograft model that consumption of fish oil significantly inhibited the growth of pancreatic adenocarcinoma and decreased cellular nucleotide level in tumor tissues. Furthermore, fish oil consumption induced an increment of GSSG/GSH ratio, an upregulation of xCT and CTH proteins in tumor tissues. In conclusion, DHA significantly inhibited survival of PDAC cells both in vitro and in vivo through its recently identified novel mode of action, including an increment in the ratio of GSSG/GSH and NADP/NADPH respectively, and promoting reduction in the levels of nucleotide synthesis.

Effect of Pulsed Light Irradiation on Bioactive, Nonvolatile Components and Antioxidant Properties of Caterpillar Medicinal Mushroom Cordyceps militaris (Ascomycetes).

The caterpillar medicinal mushroom Cordyceps militaris contains many bioactive components, such as adenosine, cordycepin, and polysaccharides. In this study, C. militaris was exposed to 0, 3, 6, or 9 pulses of light irradiation to estimate changes in vitamin D2, bioactive compounds, nonvolatile taste components, and antioxidant properties. In addition, we compared the components and properties of C. militaris mycelia and solid waste medium that had been treated with pulsed light (PL) irradiation. Overall, PL irradiation of C. militaris increased the vitamin D2 content and increased the total amino acid levels 9-48%; the antioxidant properties of the mycelia treated with 0 pulses and of the solid waste medium treated with 3 pulses all exhibited lower half-maximal effective concentrations. Therefore, PL irradiation affected the amounts of bioactive compounds, but the irradiated samples still contained intense umami taste and a sufficient amount of antioxidant components.

Compositional Differences of the Winter Culinary-Medicinal Mushroom, Flammulina velutipes (Agaricomycetes), under Three Types of Light Conditions.

The focus of this study was to investigate the effect of light on the cultivation and the amounts of bio-active components in Flammulina velutipes. The mushrooms were cultivated under fluorescent tube (T8) grow lights, lightemitting diodes (LEDs), and cold-cathode fluorescent lamps. The biological efficiency of the T8 lights was the highest, at 92%. The crude fat content, crude fiber content, polysaccharide content, and ergosterol content were highest under the LEDs, at 2.9 g/100 g, 7.9 g/100 g, 3.9 g/100 g, and 1.4 mg/g, respectively. Moreover, vitamin D2 (1.9 µg/g) was generated only under light from LEDs. Principal component analysis showed that F. velutipes cultivated under the 3 different lighting conditions showed different profiles for proximate composition, nutritional compounds, and principal fatty acids.

Antiproliferative Activities of Hot Water Extracts from Culinary-Medicinal Mushrooms, Ganoderma tsugae and Agrocybe cylindracea (Higher Basidiomycetes) on Cancer Cells.

Using anticancer agents to progress chemotherapy to inhibit the proliferation of cancer cells is an effective means. Two medicinal mushrooms, Ganoderma tsugae and Agrocybe cylindracea, exhibited various physiological effects, and the antiproliferation effect on HL-60, Hep 3B, and C6 cells was studied. The viability of different cancer cells was decreased significantly by hot water extracts from different forms of G. tsugae and A. cylindracea. The hot water extracts from the fruit body, mycelium, and filtrate of A. cylindracea were less effective in inhibiting the antiproliferation of C6, Hep 3B, and HL-60 cells than were those from G. tsugae, as evidenced by their IC50 values. The IC50 values of G. tsugae on C6, Hep 3B, and HL-60 cells were 1.13, 2.73, and 2.60 mg/mL, respectively, whereas those of baby G. tsugae were 1.87, 2.63, and 3.12 mg/mL, respectively. In addition, the filtrates of G. tsugae on C6 and Hep 3B cells were 2.81 and 2.80 mg/mL, respectively. The morphological transformation of 3 cancer cells was observed clearly, and the possible mechanism would be necrosis, apoptosis, or differentiation. Owing to the noticeable effect on antiproliferation of hot water extracts, especially those from G. tsugae, the extract could be of great potential to be used as an alternative cancer therapy.

Effect of UV-B Irradiation on Physiologically Active Substance Content and Antioxidant Properties of the Medicinal Caterpillar Fungus Cordyceps militaris (Ascomycetes).

Ultraviolet-B (UV-B) light irradiation is a well-known technique for converting vitamin D2 from ergosterol in mushroom fruit bodies. Mushrooms are a natural and nonanimal food source of vitamin D2. We studied the effect of UV-B light irradiation on the amount of vitamin D2 and physiologically active substances in Cordyceps militaris and their antioxidant properties. After UV-B irradiation for 2 hours, the vitamin D2 content of freshly harvested C. militaris fruiting bodies, mycelia, whole submerged culture (WSC), and homogenized submerged culture (HSC) increased from 0 to 0.03 to 0.22 to 1.11 mg/g, but the ergosterol content was reduced from 1.36 to 2.50 to 1.24 to 2.06 mg/g, respectively. After UV-B irradiation, the amount of adenosine, cordycepin, and ergothioneine of fruiting bodies dramatically increased 32-128%, but the polysaccharide content slightly decreased 36%. The reverse trends were observed in mycelia, WSC, and HSC. UV-B irradiation could reduce the effective concentrations at 50% of fruiting bodies for ethanolic and hot water extracts in reducing power, scavenging, and chelating abilities, whereas mycelia, WSC, and HSC of ethanolic extracts increased effective concentrations at 50% in reducing power, scavenging, and chelating abilities. UV-B irradiation slightly increased flavonoid content (10-56%) and slightly affected total phenol content.

Enhancement of antioxidant properties and increase of content of vitamin D2 and non-volatile components in fresh button mushroom, Agaricus bisporus (higher Basidiomycetes) by γ-irradiation.

Agaricus bisporus is a popular culinary-medicinal mushroom in Taiwan, and γ-irradiation could extend its shelf life. Our objective was to study the content of vitamin D2 and the taste components and antioxidant properties of ethanolic extracts from A. bisporus with various doses of γ-irradiation. After irradiation, the vitamin D2 content of 5-10 kGy irradiated mushrooms was in the range of 5.22-7.90 µg/g, higher than that of the unirradiated control (2.24 µg/g). For all treatments, the total content of soluble sugars and polyols ranged from 113 to 142 mg/g, and the monosodium glutamate-like components ranged from 6.57 to 13.50 mg/g, among which the 2.5 kGy irradiated sample has the highest content of flavor 5'-nucleotide. About antioxidant properties, 10 kGy irradiated samples exhibited lower EC50 values than did other samples. EC50 values were less than 5 mg/mL for ethanolic extracts. Total phenols were the major antioxidant components and the total content was 13.24-22.78 mg gallic acid equivalents/g. Based on the results obtained, γ-irradiation could be used to improve the vitamin D2 content and intensity of umami taste in fresh mushrooms. In addition, γ-irradiation not only maintained the antioxidant properties of mushrooms but also enhanced the antioxidant properties to some extent.

Nonvolatile taste components of culinary-medicinal maitake mushroom, Grifola frondosa (Dicks.:Fr.) S.F. Gray.

Culinary-medicinal maitake mushroom Grifola frondosa (Dicks.: Fr.) S.F. Gray mycelium was inoculated into wheat, a new product was formed after fungal fermentation, and its nonvolatile taste components were studied. Contents of crude ash, fat, fiber, and protein were higher in fruit bodies and mycelia, whereas carbohydrate contents were higher in the uninoculated and fermented wheat. Contents of total soluble sugars and polyols were 234.06, 111.70, 88.58, and 28.83 mg/g for fermented wheat, fruiting bodies, mycelia, and wheat, respectively. Contents of total free amino acids were in the descending order of mycelia > fermented wheat > fruiting bodies > wheat. Contents of total 5'-nucleotides were in the descending order: fruiting bodies > mycelia > fermented wheat > wheat. Based on the results obtained, fruiting bodies and mycelia possessed highly intense umami taste. Overall, as a result of solid-state fermentation, fermented wheat contained more taste components and a higher equivalent umami concentration than wheat did.

Preparation of culinary-medicinal maitake mushroom, Grifola frondosa (Dicks.: Fr.) S.F. Gray (Aphyllophoromycetideae)-fermented wheat and its antioxidant properties.

The optimization of solid-state fermentation conditions for mycelial growth in wheat by culinary-medicinal maitake mushroom, Grifola frondosa (Dicks.: Fr.) S.F. Gray was studied. The results from the center of the design analysis showed that the recommended optimal conditions for carbon, nitrogen sources, and temperature were 19 mg lactose/g, 2.0 mg malt extract/g, and 30 degrees C, respectively. Under these conditions, the mycelial biomass of 533.1 mg/g was obtained in fermented wheat, comparable to that (545.7 mg/g) obtained using the one-factor-at-a-time method. Based on the results obtained, EC50 values of ethanolic and hot water extracts from fermented wheat were 1.13-15.27 mg/mL, indicating that fermented wheat was effective in antioxidant activity, reducing power, scavenging ability on 1,1-diphenyl-2-picrylhydrazyl radicals, and chelating ability on ferrous ions. Total phenol contents of both extracts were 13.35 and 23.01 mg/g, respectively. Accordingly, the information obtained would be applicable for the cultivation and consumption of G. frondosa-fermented wheat to provide its beneficial health effects.

Antioxidant properties of Glossogyne tenuifolia.

Glossogyne tenuifolia (Labill) Cass. (Compositae) is a special medicinal plant in the Pescadores Islands. Ethanolic, cold and hot water extracts were prepared from the dried herb and their antioxidant properties and components were studied. Ascorbic acid, alpha-tocopherol, butylated hydroxyanisole, citric and ethylenediaminetetraacetic acids were used in assays for comparison. With regard to EC(50) values in antioxidant activity, ethanolic and hot water extracts (0.08 and 0.09 mg/ml) were much more effective than the cold water extract (0.76 mg/ml). At 1.0 mg/ml, reducing capacities were 1.57, 0.31 and 1.04 for ethanolic, cold water and hot water extracts, respectively. Scavenging abilities on 1,1-diphenyl-2-picrylhydrazyl radicals were in descending order: ethanolic > cold water > hot water extracts. At 20 mg/ml, the hot water extract chelated all hydroxyl ions (100%) whereas the scavenging ability of the cold water extract was 68.86%. Chelating abilities on ferrous ions were in descending order: cold water > hot water > ethanolic extracts. Phenols were found to be the major antioxidant components. All EC(50) values were below 20 mg/ml, and some even below 0.1 mg/ml, indicating that all three extracts from G. tenuifolia were rich in antioxidant properties.