Screening anti-fatigue components of American ginseng saponin by analyzing spectrum-effect relationship coupled with UPLC-Q-TOF-MS.

Background: American ginseng has an obvious anti-fatigue effect, but the effective material basis is still unclear. The spectrum-effect relationship is a scientific method that studies the correlations between chemical spectra and pharmacological effect. Objective: To reveal the real bioactive compounds in American ginseng saponin (AGS) based on a study of the underlying correlations between these compounds' occurrence in rat serum after their intake of AGS and the anti-fatigue effect of AGS. Methods: We utilized ultra-performance liquid chromatography (UPLC) with quadrupole and time-of-flight mass spectrometry (Q-TOF-MS) to analyze the extract of AGS and its constituents in serum after oral administration in rats. The anti-fatigue effect of AGS in rats was measured using the time weight-bearing swimming technique, the content of blood urea nitrogen, hepatic glycogen, and blood lactic acid. The relationship between the peak area values in fingerprints from rat serum and pharmacodynamic parameters of AGS was established using correlation analysis with partial least square regression (PLSR) method and gray correlation method. Results: We detected and identified 22 compounds from extract, and 8 prototype components from serum. Through PLSR and gray correlation method, it was found that the ginsenosides Re, Rb1, and Rb2 were significantly positively related to the pharmacodynamic data. Conclusions: Based on the spectrum-effect relationship, PLSR and gray correlation method can be used to screen for the anti-fatigue components available in AGS. Such an approach is of practical significance as it provides an effective means for exploring the material basis for the efficacy of American ginseng, particularly as an anti-fatigue agent.

Clausenlanins A and B, Two Leucine-Rich Cyclic Nonapeptides from Clausena lansium.

Two new cyclic nonapeptides, named clausenlanins A (1) and B (2), were isolated from the roots and rhizomes of Clausena lansium. Their structures were elucidated as cyclo-(Gly1-L-Leu2-L-Ile3-L-Leu4-L-Leu5-L-Leu6-L-Leu7-L-Leu8-L-Leu9) (1) and cyclo-(Gly1-L-Leu2-L-Val3-L-Leu4-L-Leu5-L-Leu6-L-Leu7-L-Leu8-L-Leu9) (2) respectively on the basis of extensive spectroscopic analysis, particularly 2D NMR spectra taken at the temperature of 338 or 303 K and MS.