Structural characterization and antioxidant activity of pectic polysaccharides from Veronica peregrina L.

Background: Pectins are a class of acidic polysaccharides with complex structures. Different pectin molecules are composed of different domains, which have an important impact on their biological activity. Objective: This study aimed to determine the structural features and the antioxidant activities of the pectic polysaccharides isolated from Veronica peregrina L. Methods: The polysaccharide was isolated from Veronica peregrina L by water extraction and fractionated by ion exchange chromatography and gel permeation chromatography. The structure features of the pectic polysaccharides were determined by Fourier transforminfrared spectroscopy (FT-IR) and Nuclear magnetic resonance (NMR). The antioxidant activities was evaluated by the DPPH, OH and ABTS radical scavenging ability. Results: WVPP-A2b and WVPP-A3b, with molecular weights of 48.7 × 104 and 77.6 × 104 kDa, respectively, contained homogalacturonan (HG), rhamnogalacturonan I (RG-I), and rhamnogalacturonan II (RG-II) domains with a mass ratio of 2.08:2.64:1.00 and 3.87:4.65:1:00, respectively. The RG-I domain contained an arabinogalactan II backbone and arabinans consisting of t-Araf, (1→5)-α-Araf, and (1→3,5)-α-Araf. WVPP-A3b also contained short chains consisting of the [t-Araf-(1→5)-α-Araf-(1→] structural unit. WVPP-A3b showed stronger ability to scavenge DPPH, hydroxyl, and ABTS radicals, which was potentially associated with its high content of galacturonic acid and presence of the HG domain. Conclusion: The results provide information for enhancing knowledge of the structureactivity relationship of pectic polysaccharides from V. peregrina and their potential application in the healthcare food field.

Effect of Extracts from Veronica peregrine on Breast Cancer Cell-induced Osteoclastic Bone Metastasis via Inhibiting Runx2 Activation / 中国实验方剂学杂志

ObjectiveTo investigate inhibitory effect of extracts from Veronica peregrina （EVP） on the osteoclastic bone metastasis induced by breast cancer cells. MethodBone metastasis model was established by injection of MDA-MB-231 cells， a human breast cancer cell line， into the left ventricle of BALB/c nude mice. The expression of human cytokeratin-19 （Ck-19） gene in mouse bone marrow was determined by nested polymerase chain reaction（PCR） to assess the bone metastasis of MDA-MB-231 cells. To assess the effects of EVP on the activation of bone marrow macrophages （BMMs）， we counted the multinuclear cells and measured the secretion of Cathepsin K. Western blot was adopted to assess the effects of EVP on receptor activator of nuclear factor-κB （RANK）， Runt-related transcription factor 2 （ Runx2 ）， phosphorylated Runx2 （p-Runx2）， and matrix metalloproteinase-9 （MMP-9） in BMMs. Gelatin zymography was employed to determine the activities of matrix metalloproteinases （MMPs）. ResultCompared with that in the blank group， Ck-19 expression was down-regulated in EVP groups （P<0.05）. The multinucleated cells increased when the BMMs were induced by soluble receptor activator of nuclear factor-κB ligand （sRANKL）， which was inhibited by EVP （P<0.05）. The level of cathepsin K in the supernatant of sRANKL group increased compared with that of the blank group， while EVP groups had lower cathepsin K levels than sRANKL group （P<0.05）. Compared with the blank group， the sRANKL group showed up-regulated RANK expression， Runx2 phosphorylation， and MMP-9 expression （P<0.05）， while the expression levels of RANK， p-Runx2， and MMP-9 were down-regulated when the cells were incubated with EVP （P<0.05）. Furthermore， exposure of BMMs to sRANKL resulted in an increase in gelatin hydrolyzation compared with the blank group （P<0.01）， which， however， was reversed in EVP groups （P<0.05）. ConclusionEVP significantly inhibits bone marrow metastasis of MDA-MB-231 cells， which may be associated with the suppression of osteoclast activation by inhibiting Runx2 phosphorylation.