Structural Characterization of a Novel Polysaccharide from Lepidium meyenii (Maca) and Analysis of Its Regulatory Function in Macrophage Polarization in Vitro

Abstract

In our previous study, three novel polysaccharides, named MC-1, MC-2, and MC-3, were separated from the roots of maca (Lepidium meyenii), which is a food source from the Andes region. The structural information and immunomodulatory activity of MC-1 were then investigated. The structure and activity of MC-2 are still unknown. In this study, structural characterization revealed that MC-2 has an average molecular weight of 9.83 kDa and is composed of arabinose (20.9%), mannose (4.5%), glucose (71.9%), and galactose (2.7%). The main linkage types of MC-2 were proven to be (1→5)-α-l-Ara, (1→3)-α-l-Man, (1→)-α-d-Glc, (1→4)-α-d-Glc, (1→6)-α-d-Glc, and (1→6)-β-d-Gal by methylation and NMR analyses. Congo red assay showed that MC-2 possesses a triple-helix conformation. Immunostimulating assays indicated that MC-2 could induce M1 polarization of original macrophages and convert M2 macrophages into M1 phenotype. Although MC-2 could not shift M1 macrophages into M2, it could still inhibit inflammatory reactions induced by lipopolysaccharide. Furthermore, Toll-like receptor 2, tTll-like receptor 4, complement receptor 3, and mannose receptor were confirmed as the membrane receptors for MC-2 on macrophages. These results indicate that MC-2 could potentially be used toward hypoimmunity and tumor therapies.

Antioxidant activity in HepG2 cells, immunomodulatory effects in RAW 264.7 cells and absorption characteristics in Caco‐2 cells of the peptide fraction isolated from Dendrobium aphyllum

“…The cell lines HepG2, RAW 264.7 and Caco‐2 were thawed in a water bath (37 °C) immediately and centrifugation at 1000 g for 10 min (Zhang et al ., ), subsequently incubated in a humidified atmosphere of 5% CO 2 at 37 °C. The DMEM high‐glucose medium contained 10% heat‐inactivated foetal bovine serum, 100 μg mL −1 streptomycin and 100 U mL −1 penicillin.…”

Maca (Lepidium meyenii) as a source of macamides and polysaccharide in combating of oxidative stress and damage in human erythrocytes

“…The glucose content of Yunnan maca polysaccharide extracted by ultrasonic circulating technique was larger than rhamnose, galacturonic acid, galactose, xylose and arabinose (Zhang et al ., ). A polysaccharide from Peru maca mainly consisted of arabinose, mannose, glucose and galactose at approximate percentages of 20.9%, 4.5%, 71.9% and 2.7%, respectively (Zhang et al ., ). However, arabinose was the major monosaccharide in Yunnan maca (Zha et al ., ).…”

Optimization of Maca polysaccharide extraction process and its chemo‐protective effects on cyclophosphamide‐induced mice

“…In the previous works, immunomodulatory activities of LMP were examined at cell level using macrophages as models because they can initiate immune responses by phagocytosis, produce cytotoxic molecules, and promote cytokines secretion. Zhang separated a polysaccharide from Maca and evaluated its immunomodulatory activity (Zhang, Wu, et al, ). They found that the polysaccharide can enhance the pinocytic and phagocytic capacities and increase the levels of NO, TNF‐α, and IL‐6 in the macrophage cell (RAW 264.7 cells).…”

“…Many works have presented details of the compositions, structures, and biological activities of the LMP (Zang et al, ). It was found that the polysaccharide was mainly composed of glucose, arabinose, galactose, and mannose (Zhang, Wu, et al, , Li et al, ). The LMP potentially plays the role in both immunity enhancement and antitumor function.…”

“…The LMP potentially plays the role in both immunity enhancement and antitumor function. It was reported that LMP was used in cell experiments to directly stimulate the macrophage RAW264.7, for the purpose of detecting the proliferation and phagocytic abilities of the cells; as well as the expression of relevant proteins, RNA transcription, and cytokines secretion (Zhang, Wang, Lai, & Wu, , Zhang, Wu, et al, , Stojanovska, Nelson, Day, & Apostolopoulos, ). However, the animal experiments related to the in‐vivo immunomodulatory effect for LMP were rarely reported.…”