Nitrogen Application Can Optimize Form of Selenium in Soil in Selenium-Rich Areas to Affect Selenium Absorption and Accumulation in Black Wheat.

The composition and form of selenium in the soil have significant effects on the selenium content of crops. In this study, we investigated the selenium absorption pathway in plants by studying the interaction between nitrogen fertilizer and soil selenium. Our results showed that the selenium concentration enrichment factors (CEF) varied within the same region due to nitrogen fertilizer application, where they ranged from 1.33 to 5.02. The soil selenium flow coefficient (mobility factor, MF) increased with higher nitrogen application rates. The sum of the MF values for each soil layer treated with nitrogen application rates of 192 kg hm-2 and 240 kg hm-2 was 0.70, which was 64% higher than that for the control group with no nitrogen application. In the 0-20 cm soil layer, the highest summed water-soluble and exchangeable selenium and relative percentage of total selenium (12.45%) was observed at a nitrogen application rate of 240 kg hm-2. In the 20-40 cm soil layer, the highest relative percentage content of water-soluble and exchangeable selenium and total selenium (12.66%) was observed at a nitrogen application rate of 192 kg hm-2. Experimental treatment of black wheat with various concentrations of sodium selenite showed that selenium treatment at 50 µmol L-1 significantly increased the reduced glutathione (GSH) levels in the leaves and roots of seedlings, where the GSH contents increased by 155.4% in the leaves and by 91.5% in the roots. Further analysis of the soil-black wheat system showed that nitrogen application in selenium-rich areas affected the soil selenium flow coefficient and morphological composition, thereby changing the enrichment coefficient for leaves (0.823), transport capacity from leaves to grains (-0.530), and enrichment coefficient for roots (0.38). These changes ultimately affected the selenium concentration in the grains of black wheat.

Anticancer activity and mechanism of total saponins from the residual seed cake of Camellia oleifera Abel. in hepatoma-22 tumor-bearing mice.

We have previously demonstrated that several new saponins from the seed cake of Camellia oleifera Abel. exhibited antiproliferative activity against human tumor cells in vitro. The current study investigated the effect of total saponins from the residual seed cake of Camellia oleifera Abel. (TSSC) on anticancer activity in hepatoma-22 tumor-bearing mice and discovered that TSSC induced apoptosis of cancer cells in mice with hepatoma-22 solid tumors. In mice with hepatoma-22 solid tumors, daily intratumoral injections with TSSC at the doses of 20 µg kg-1, 100 µg kg-1, or 2000 µg kg-1 were administered for 10 consecutive days, a regimen which was well tolerated by the mice and significantly inhibited tumor growth. Moreover, TSSC promoted solid tumor cell apoptosis, upregulated the protein expression of Bax, and downregulated the protein expression of Bcl-2 in response to regulate apoptosis of cancer cells in mice bearing hepatoma 22 solid tumors. At the same time, the direct structure-activity relationship between camelliasaponins B1, Bcl-2 and MDM2 in TSSC was investigated by molecular docking. It was verified that the glycosidic ligand on C3 is the main source of anticancer activity. Taken together, these results indicated that TSSC could exhibit anticancer activity and increase apoptosis of cancer cells in hepatoma-22 tumor-bearing mice, making it a potential adjuvant drug after further investigation in the future.