A linear polyketide, amphirionin-4 (1), has been isolated from cultivated algal cells of the marine dinoflagellate Amphidinium species. The structure was elucidated on the basis of detailed analyses of 1D and 2D NMR data, and the absolute configurations of C-4 and C-8 were determined using the modified Mosher's method. Amphirionin-4 (1) exhibited extremely potent proliferation-promoting activity on murine bone marrow stromal ST-2 cells (950% promotion) at a concentration of 0.1 ng/mL.
Background: Many studies that use food containing Panax genus plants (PGPs) have been conducted but most of them have not mentioned the effective compounds ginsenosides and their composition. Therefore, we conducted a systematic review and meta-analysis of time to exhaustion as an index of exercise endurance with ingestion of PGPs or ginsenosides to reveal their effects. Methods: We performed a systematic review with a comprehensive and structured literature search using seven literature databases, four clinical trial databases, and three general web search engines during 15–22 March 2021. A random-effects model was applied to calculate the standardized mean difference (SMD) and 95% confidence interval (CI) as the difference between the mean in the treatment and placebo groups. We evaluated the risk of bias of individual studies along with the risk of bias tool in the Cochrane handbook. This study was funded by Maruzen Pharmaceuticals Co., Ltd. (Hiroshima, Japan). The protocol for this study was registered with the UMIN-CTR (No. UMIN000043341). Results: Five studies met the inclusion criteria. The number of total participants was 90, with 59 in the ingestion-PGPs group and 64 in the control group, because three studies were crossover-design trials. We found that ingestion of PGPs or ginsenosides significantly improved exercise endurance (SMD [95% CI]: 0.58 [0.22–0.95], I2 = 0%). It was suggested that ginsenoside Rg1 (Rg1) and PGPs extract containing Rg1 were significantly effective in improving exercise endurance (SMD [95% CI]: 0.70 [0.14–1.27], I2 = 30%) by additional analysis. Conclusions: This systematic review suggests that the ingestion of PGPs or ginsenosides, especially Rg1, is effective in improving exercise endurance in healthy adults. However, further high-quality randomized controlled trials are required because imprecision and publication bias cannot be ignored in this systematic review.
In the Ariake Sea, Japan, the pennate diatom Asteroplanus karianus has formed massive blooms each winter since 2008. During the peak of the bloom, seaweeds of the genus Pyropia, which are cultivated to make nori products, are discolored due to nutrient deficiency. We investigated the nutrient dynamics associated with A. karianus blooms in the Ariake Sea and measured the uptake of nitrate and phosphate by an axenic strain of A. karianus. Dissolved inorganic nitrogen and dissolved inorganic phosphorus in the coastal waters were significantly lower in areas where A. karianus cells were proliferating (r ≤ −0.955, p < 0.01), and these nutrients were severely depleted during the period of blooming. In the laboratory, the maximum uptake rate and half-saturation constant of A. karianus cultures were 27.3 fmol N cell −1 h −1 and 7.44 µmol N l −1 , respectively, for nitrate and 22.6 fmol P cell −1 h −1 and 3.61 µmol P l −1 , respectively, for phosphate. This study demonstrates that A. karianus blooms significantly deplete nutrients in the water column. The winter blooms presumably deplete dissolved inorganic nitrogen and dissolved inorganic phosphorus from the water column and may indirectly cause Pyropia nutrient deficiency.
Two highly potent cytotoxic 26-membered macrolides, isocaribenolide-I (1) and a chlorohydrin 2, together with known amphidinolide N (3), have been isolated from a free-swimming dinoflagellate Amphidinium species (KCA09053 and KCA09056 strains) collected off Iriomote Island, Japan. The structures of 1 and 2 were determined to be a congener of 3 with an isobutyl terminus and the chlorohydrin form of 3, respectively, by detailed analyses of spectroscopic data. The relative stereochemistries of 1 and 2 were elucidated by the conformational analyses based on NMR data.
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