Comparative Study of the Chemical Constituents and Bioactivities of the Extracts from Fruits, Leaves and Root Barks of Lycium barbarum

Abstract

The fruits, leaves and root barks of L. barbarum plant are widely used as functional foods and as ingredients in traditional Chinese prescriptions and patent medicines. They are considered to have different pharmacological activities and health benefits because of their diverse constituents. Here, the chemical constituents of the extracts from fruits, leaves and root barks of L. barbarum were compared by ultra-high performance liquid chromatography coupled with high resolution mass spectrometry (UPLC-HR-MS). A total of 131 compounds were identified and seven of them were quantified. Among them, 98, 28 and 35 constituents were detected in fruits, leaves and root barks respectively. Dicaffeoylspermidine/spermine derivatives were the most detected compounds (74/131); among them, dicaffeoylspermine isomers and propionyl-dicaffeoylspermidine were found in root barks in very large amounts (e.g., kukoamine B = 10.90 mg/g dry powder); dicaffeoyl-spermidine isomers were detected in fruits/leaves in a high amount, and many of their glycosylated derivatives were mainly detected in fruits. In addition, six saponins from L. barbarum fruits were reported for the first time, and 5,6-dihydrosolasonine was reported for the first time in plants. The activity assays showed that the root bark extract possessed the strongest antioxidative activity and cytotoxicity, which was presumed due to the large amount of dicaffeoylspermine/spermidines in root barks. Fourteen potential bioactive components from fruits were identified by a target cell-based screening method. These results will help to understand the different biological activities of these three parts of L. barbarum plant and will benefit the discovery of new functional components.

Keywords: UPLC-MS; antioxidative activities; chemical compounds; comparative study; organs of Lycium barbarum.

Figure 1

The HR-Orbitrap MS/MS spectrum (a) and proposed fragmentation pathway (b) of 5,6-dihydrosolasonine.

Figure 2

A diagram for rapid classification and tentative identification of chemical constituents in the extracts of fruits, leaves and root barks of L. barbarum by UPLC-HR-MS, and the structures of standard compounds in different classes.

Figure 3

Total ion chromatograms (TICs) of extracts of fruits, leaves and root barks in positive and negative ion mode using UPLC-HR-MS. All the compound numbers were same with those shown in Table 1.

Figure 4

Protection effect of different concentrations of extracts from fruits (a), leaves (b) and root barks (c) on 100 µM H₂O₂-induced intracellular ROS production in L02 cells. Results were expressed as means ± SD, n = 3. * p < 0.05, ** p < 0.01, *** p < 0.001, vs. the H₂O₂ treated group. (d) Confocal imaging of intracellular ROS levels after H₂O₂ stimulation in the presence of extracts of fruits (1 mg/mL), leaves and root barks (0.2 mg/mL) (scale bar, 50 μm).

Figure 5

The cytotoxicities of different concentrations of extracts from fruits, leaves, root barks (a) and kukoamine B (b) towards L02 cells. Results were expressed as means ± S.D., n = 3. ** p < 0.01, *** p < 0.001, **** p < 0.0001.

Figure 6

TIC of the extract of L02 cells treated and untreated with fruit extract. All the compound numbers were same with those shown in Table 1 and Table S4.