Pharmacokinetics and tissue distribution study of hupehenenine in rats: A novel isosteroid alkaloid isolated from Bulbus Hupehensis Fritillariae.

Hupehenenine is a novel isosteroid alkaloid that was first isolated from Bulbus Hupehensis Fritillariae. The inhibitory proliferation effect of hupehenenine and its three related alkaloid derivatives, including o-caproyl-hupehenenine, o-(2-furanoyl)-hupehenenine, and Δ5(6) -isopeimine on human lung cancer cell line, human chronic myeloid leukemia cell line, and human thyroid duct cancer cell line in vitro, has been identified. This study first developed a sensitive HPLC-MS/MS method for the simultaneous quantification of hupehenenine and three alkaloid derivatives in rat plasma and tissues. The developed method was validated, and it was linear over the concentration range of 1-800 ng/mL for all analytes with R2 ≥ 0.9939 and 0.9972, respectively, in rat plasma and rat liver homogenate. The lower limit of quantitation was 1 ng/mL for all analytes. The intra-day and inter-day precision and accuracy were satisfactory. This validated method was successfully applied to investigate the pharmacokinetics and tissue distribution of hupehenenine in rats. In pharmacokinetic study, the maximum plasma concentration of rats exists gender difference. Tissue distribution study showed that hupehenenine has good affinity for multiple tissues but is unable to cross the blood-brain barrier. These results may provide a useful reference for further research of hupehenenine and its three related alkaloid derivatives.

Effects of Drought Stress on Peramine and Lolitrem B in Epichloë-Endophyte-Infected Perennial Ryegrass.

Perennial ryegrass (Lolium perenne) infected by Epichloë endophytes contains alkaloids that are responsible for toxicosis in many countries. Drought may greatly affect the alkaloids contents of symbionts. The E+ perennial ryegrass was grown in pots with different soil moisture conditions (15%, 30%, 45% and 60% relative saturation moisture content, RSMC) for four months in a greenhouse of Lanzhou University, and then, the aboveground tissues were collected. The levels of peramine and lolitrem B in all plant samples were determined. The results showed that the drought stress significantly (p < 0.05) increased the peramine concentrations of perennial ryegrass but did not affect the lolitrem B concentrations. In addition, the drought stress significantly (p < 0.05) reduced the plant height and dry matter of perennial ryegrass. In conclusion, drought stress affects the peramine concentration in the perennial ryegrass−endophyte symbiont but may not affect the lolitrem B concentration.

Effects of Seasonal Variation on the Alkaloids of Different Ecotypes of Epichloë Endophyte-Festuca sinensis Associations.

The Epichloë endophyte-Festuca sinensis association produces alkaloids which can protect the host plant from biotic and abiotic stresses. Alkaloid concentrations depend on the genetic predisposition of grass and endophyte, and are affected by the environment. Endophyte infected F. sinensis of six ecotypes were grown in experimental field and greenhouse for 2 years. Their aboveground plant tissues were collected each season to test for peramine, lolitrem B, and ergot concentrations. The results showed that seasonal changes affected the peramine, lolitrem B and ergot concentrations of Epichloë endophyte-F. sinensis associations; and these three different alkaloids responded differently to seasonal variation. The peramine concentration of six ecotypes of F. sinensis decreased significantly (p < 0.05) from spring to autumn. The lolitrem B concentration of F. sinensis was higher in autumn than in other seasons. Ergot concentrations of five ecotypes (41, 57, 84, 99, and 141) of F. sinensis peaked in the summer, and lowered in spring and autumn. In addition, the ecotype has insignificant effect (p > 0.05) on the peramine and lolitrem B concentrations of F. sinensis, but it has a significant impact (p < 0.05) on the ergot concentrations. We concluded that the seasonal variation and ecotypes can influence the alkaloids produced by the F. sinensis-endophyte associations, but the effects of seasonal conditions on the alkaloid concentrations are more pronounced than ecotypes.