Preparation, Characterization, and Immuno-Enhancing Activity of Polysaccharides from Glycyrrhiza uralensis

Effect of Licorice polysaccharides before and after honey-processing on improving chronic fatigue syndrome and its mechanism

Honey-processed Licorice, a type of Glycyrrhizae Radix et Rhizome processed with honey, is renowned for its superior effectiveness in tonifying the spleen and invigorating Qi compared to the raw product. Our previous research showed that flavonoids and saponins in licorice changed after processing. Therefore, the purpose of this study was to investigate the changes of chemical composition and biological activity of polysaccharides after processing. The weight-average molecular weight (Mw) measured by HPGPC showed that the Mw distribution range of raw licorice polysaccharides (RLP) was 1.34 × 103-1.36 × 106 Da, and the Mw distribution range of honey-processed licorice polysaccharides (HPLP) was 1.15 × 103-1.17 × 106 Da, the Mw distribution range of the two were basically the same. The analysis of monosaccharide composition showed that the types of monosaccharide in RLP and HPLP were consistent, and the contents of mannose, rhamnose, glucuronic acid, galacturonic acid and glucose in HPLP were significantly higher than those in RLP. Furthermore, the impact of these polysaccharides on chronic fatigue syndrome (CFS) showed that the high-dose group of HPLP had significantly better improvement of IL-2, IFN-γ and IgA than RLP. Multi-omics analysis showed that both of them could affect the immune system by regulating immunoglobulin, B-cell signaling pathway and T cell phenotypic differentiation. Interestingly, the HPLP could affect the natural killer cells mediated cytotoxicity on this basis. The above results indicated the effects of honey processing on the chemical composition and biological activities of licorice polysaccharides and elucidated the underlying mechanism of the superior biological activities of HPLP over RLP.

In vivo pharmacokinetics of Glycyrrhiza uralensis polysaccharides

Glycyrrhiza uralensis polysaccharides (GUPS) are widely applied in biomedicine and functional food due to their multiple pharmacological activities and low toxicity. Despite their widespread use, the in vivo metabolic profile of GUPS remains poorly understood. To address this gap, we developed a quantitative analysis method that involves labeling GUPS with visible fluorescein (5-DTAF) and near-infrared (NIR) fluorescein (Cy7), resulting in stable conjugates with substitution degrees of 0.81% for 5-DTAF and 0.39% for Cy7. The pharmacokinetic studies showed a biphasic elimination pattern in the blood concentration-time curve following both intravenous and oral administration, consistent with a two-compartment model. Using fluorescence quantification and NIR imaging, we observed that GUPS was distributed to various tissues, exhibiting higher concentrations particularly in liver, kidney and lung. Excretion studies indicated that feces were the major excretion pathway of GUPS after oral administration (60.98%), whereas urine was the main pathway after intravenous administration (31.16%). Notably, GUPS could be absorbed rapidly by gut (Tmax 1 ± 0.61 h) and showed a biological half-time t1/2 26.4 ± 7.72 h after oral administration. Furthermore, the Caco-2 cells uptake studies illustrated that macropinocytosis and clathrin-mediated endocytosis were participated in the transport of GUPS in intestine epithelium. This comprehensive analysis of the in vivo pharmacokinetics of GUPS not only enhances our understanding of its metabolic pathways but also establishes a foundational basis for its clinical application, optimizing its therapeutic potential and safety profile.

Natural polysaccharides regulate intestinal microbiota for inhibiting colorectal cancer

The gastrointestinal tract is an important part of the human immune system. The gut microbiome, which constitutes a major component of the gastrointestinal tract, plays a crucial role in maintaining normal physiological functions and influences the development, diagnosis, and immunotherapy of colorectal cancer (CRC). Natural polysaccharides can be extracted from animals, plants, and traditional Chinese medicines. They serve as an essential energy source for the gut microbiome, promoting probiotic proliferation and regulating the intestinal microecological balance. Moreover, polysaccharides exhibit anti-tumor effects due to their immune regulatory functions and low toxicity. This review focuses on discussing these anti-tumor effects in CRC, along with improving gut microbiome dysbiosis and regulating the tumor immune microenvironment, providing evidence for effective therapeutic strategies against CRC.

Specific molecular weight of Lycium barbarum polysaccharide for robust breast cancer regression by repolarizing tumor-associated macrophages

The pro-tumorigenic M2-type tumor-associated macrophages (TAMs) in the immunosuppressive tumor microenvironment (TME) promote the progression, angiogenesis, and metastasis of breast cancer. The repolarization of TAMs from an M2-type toward an M1-type holds great potential for the inhibition of breast cancer. Here, we report that Lycium barbarum polysaccharides (LBPs) can significantly reconstruct the TME by modulating the function of TAMs. Specifically, we separated four distinct molecular weight segments of LBPs and compared their repolarization effects on TAMs in TME. The results showed that LBP segments within 50-100 kDa molecular weight range exhibited the prime effect on the macrophage repolarization, augmented phagocytosis effect of the repolarized macrophages on breast cancer cells, and regression of breast tumor in a tumor-bearing mouse model. In addition, RNA-sequencing confirms that this segment of LBP displays an enhanced anti-breast cancer effect through innate immune responses. This study highlights the therapeutic potential of LBP segments within the 50-100 kDa molecular weight range for macrophage repolarization, paving ways to offer new strategies for the treatment of breast cancer.

The traditional use, structure, and immunostimulatory activity of bioactive polysaccharides from traditional Chinese root medicines: A review

As research on traditional Chinese medicine (TCM) has expanded, our understanding of the role it can have in controlling the immune system has increased. Polysaccharides from medicinal plants exhibit numerous beneficial therapeutic properties, presumably owing to their modulation of innate immunity and macrophage function. Numerous studies have demonstrated the multiple ways whereby certain polysaccharides can affect the immune system. In addition to stimulating immune cells, such as T cells, B lymphocytes, macrophages, and natural killer cells, polysaccharides stimulate complements and increase cytokine secretion. The biological functions of polysaccharides are directly correlated with their structures. This paper summarizes the sources, TCM uses, extraction and purification methods, structural characterization, in vitro and in vivo immune activities, and underlying molecular mechanisms of TCM root polysaccharides. Moreover, the structure-activity relationships of TCM root polysaccharides are emphasized and discussed. This review can provide a scientific basis for the research and industrial utilization of TCM root polysaccharides.

Inhibition of Glycyrrhiza Polysaccharide on Human Cytochrome P450 46A1 in vitro and in vivo: Implications in Treating Neurological Diseases

BACKGROUND

Cytochrome P450 (CYP) 46A1, also known as cholesterol 24S-hydroxylase, is essential for maintaining the homeostasis of cholesterol in the brain and serves as a therapeutic target of neurodegenerative disorders and excitatory neurotoxicity. N-methyl-d-aspartate receptor (NMDAR) is a prototypical receptor for the excitatory neurotransmitter glutamate and can be specifically regulated by 24S-hydroxycholesterol (24S-HC). Glycyrrhiza is one of the most widely used herbs with broad clinical applications, which has several pharmacological activities, such as clearing heat and detoxifying, moistening the lung and relieving cough, analgesic, neuroprotective outcomes, and regulating a variety of drug activities. Glycyrrhiza is a commonly used herb for the treatment of epileptic encephalopathy. However, whether glycyrrhiza can interfere with the activity of CYP46A1 remains unknown.

OBJECTIVE

This study aimed to investigate the regulating effects of glycyrrhiza polysaccharides (GP) on CYP46A1-mediated cholesterol conversion, as well as in the modulation of related proteins.

MATERIALS AND METHODS

The effects of glycyrrhiza polysaccharide (GP) on the activity of CYP46A1 were investigated in vivo and in vitro. Moreover, the potential regulatory effects of GP on the expressions of CYP46A1, HMG-CoA reductase (HMGCR), and NMDAR were also detected.

RESULTS

The in vitro results demonstrated that glycyrrhiza polysaccharide (GP), as the main water-soluble active component of glycyrrhiza, remarkably inhibited the activity of CYP46A1 in a non-competitive mode with a Ki value of 0.7003 mg/ml. Furthermore, the in vivo experiments verified that GP markedly decreased the contents of 24S-HC in rat plasma and brain tissues as compared to the control. More importantly, the protein expressions of CYP46A1, GluN2A, GluN2B, and HMG-CoA reductase (HMGCR) in rat brains were all downregulated, whereas the mRNA expressions of CYP46A1 and HMGCR were not significantly changed after treatment with GP.

CONCLUSION

GP exhibits a significant inhibitory effect on CYP46A1 activity in vitro and in vivo, and the protein expressions of CYP46A1, HMGCR, and NMDAR are also inhibited by GP, which are of considerable clinical significance for GP's potential therapeutic role in treating neurological diseases.

Ficus carica polysaccharide extraction via ultrasound-assisted technique: Structure characterization, antioxidant, hypoglycemic and immunomodulatory activities

In this research, the ultrasound-assisted extraction (UAE) conditions of the water-soluble polysaccharide (FCPS) from Ficus carica fruits were optimized using the response surface methodology. The optimal FCPS yield was 7.97 % achieved by conducting ultrasound-assisted extraction four times at a solid-liquid ratio of 1:20 (g/mL) and an ultrasound temperature of 70 °C. Then, the structure, antioxidant properties, hypoglycemic effects, and immunomodulatory activities of FCPS were evaluated. FCPS was characterized as irregular, rough-surfaced, flaky materials consisting of pyran-type polysaccharides with α- and β-glycosidic linkages, and composed of multiple monosaccharides and only one homogeneous concentrated polysaccharide component (FCPS1) with a molecular weight of 4.224 × 104 Da. The results suggested FCPS exhibited remarkable antioxidant activity in vitro, as evidenced by improved cell viability and reduced the reactive oxygen species (ROS) levels. Meanwhile, FCPS effectively improved liver-related insulin resistance by promoting glucose consumption in hepatocytes and activated the immune response through activation of murine bone marrow-derived dendritic cells (DCs) and upregulation of interleukin 6 (IL6) and interleukin 12 (IL-12) expression. The findings demonstrate the efficacy of the UAE technique in isolating FCPS with biological functionality and FCPS could potentially serve as a beneficial organic antioxidant source and functional food, carrying important implications for future studies.

Modulating the gut microbiota is involved in the effect of low-molecular-weight Glycyrrhiza polysaccharide on immune function

Low molecular weight (6.5 kDa) Glycyrrhiza polysaccharide (GP) exhibits good immunomodulatory activity, however, the mechanism underlying GP-mediated regulation of immunity and gut microbiota remains unclear. In this study, we aimed to reveal the mechanisms underlying GP-mediated regulation of immunity and gut microbiota using cyclophosphamide (CTX)-induced immunosuppressed and intestinal mucosal injury models. GP reversed CTX-induced intestinal structural damage and increased the number of goblet cells, CD4+, CD8+ T lymphocytes, and mucin content, particularly by maintaining the balance of helper T lymphocyte 1/helper T lymphocyte 2 (Th1/Th2). Moreover, GP alleviated immunosuppression by down-regulating extracellular regulated protein kinases/p38/nuclear factor kappa-Bp50 pathways and increasing short-chain fatty acids level and secretion of cytokines, including interferon-γ, interleukin (IL)-4, IL-2, IL-10, IL-22, and transforming growth factor-β3 and immunoglobulin (Ig) M, IgG and secretory immunoglobulin A. GP treatment increased the total species and diversity of the gut microbiota. Microbiota analysis showed that GP promoted the proliferation of beneficial bacteria, including Muribaculaceae_unclassified, Alistipes, Lachnospiraceae_NK4A136_group, Ligilactobacillus, and Clostridia_vadinBB60_group, and reduced the abundance of Proteobacteria and CTX-derived bacteria (Clostridiales_unclassified, Candidatus_Arthromitus, Firmicutes_unclassified, and Clostridium). The studies of fecal microbiota transplantation and the pseudo-aseptic model conformed that the gut microbiota is crucial in GP-mediated immunity regulation. GP shows great potential as an immune enhancer and a natural medicine for treating intestinal inflammatory diseases.

The preventive effect of Glycyrrhiza polysaccharide on lipopolysaccharide-induced acute colitis in mice by modulating gut microbial communities

Acute colitis is characterised by an unpredictable onset and causes intestinal flora imbalance together with microbial migration, which leads to complex parenteral diseases. Dexamethasone, a classic drug, has side effects, so it is necessary to use natural products without side effects to prevent enteritis. Glycyrrhiza polysaccharide (GPS) is an α-d-pyranoid polysaccharide with anti-inflammatory effects; however, its anti-inflammatory mechanism in the colon remains unknown. This study investigated whether GPS reduces the lipopolysaccharide (LPS)-induced inflammatory response in acute colitis. The results revealed that GPS attenuated the upregulation of tumour necrosis factor-α, interleukin (IL)-1β, and IL-6 in the serum and colon tissues and significantly reduced the malondialdehyde content in colon tissues. In addition, the 400 mg/kg GPS group showed higher relative expressions of occludin, claudin-1, and zona occludens-1 in colon tissues and lower concentrations of diamine oxidase, D-lactate, and endotoxin in the serum than the LPS group did, indicating that GPS improved the physical and chemical barrier functions of colon tissues. GPS increased the abundance of beneficial bacteria, such as Lactobacillus, Bacteroides, and Akkermansia, whereas pathogenic bacteria, such as Oscillospira and Ruminococcus were inhibited. Our findings indicate that GPS can effectively prevent LPS-induced acute colitis and exert beneficial effects on the intestinal health.

Research progress on the mechanisms underlying poultry immune regulation by plant polysaccharides

With the rapid development of poultry industry and the highly intensive production management, there are an increasing number of stress factors in poultry production. Excessive stress will affect their growth and development, immune function, and induce immunosuppression, susceptibility to a variety of diseases, and even death. In recent years, increasing interest has focused on natural components extracted from plants, among which plant polysaccharides have been highlighted because of their various biological activities. Plant polysaccharides are natural immunomodulators that can promote the growth of immune organs, activate immune cells and the complement system, and release cytokines. As a green feed additive, plant polysaccharides can not only relieve stress and enhance the immunity and disease resistance of poultry, but also regulate the balance of intestinal microorganisms and effectively alleviate all kinds of stress faced by poultry. This paper reviews the immunomodulatory effects and molecular mechanisms of different plant polysaccharides (Atractylodes macrocephala Koidz polysaccharide, Astragalus polysaccharides, Taishan Pinus massoniana pollen polysaccharide, and alfalfa polysaccharide) in poultry. Current research results reveal that plant polysaccharides have potential uses as therapeutic agents for poultry immune abnormalities and related diseases.

Glycyrrhiza Polysaccharide Inhibits Pseudorabies Virus Infection by Interfering with Virus Attachment and Internalization

Pseudorabies virus (PRV) is one of the most important pathogens causing serious diseases and leads to huge economic losses in the global swine industry. With the continuous emergence of PRV variants and the increasing number of cases of human infection, there is an urgent need to develop antiviral drugs. In this study, we discover that Glycyrrhiza polysaccharide (GCP) has anti-PRV infection activity in vitro, and 600 μg/mL GCP can completely block viral infection. The addition of GCP simultaneously with or after PRV infection had a significant inhibitory effect on PRV. Addition of GCP at different times of the virus life cycle mainly led to the inhibition of the attachment and internalization of PRV but does not affect viral replication and release. Our findings suggest that GCP has potential as a drug against PRV infection.

Isolation, Characterization, Pharmacology and Biopolymer Applications of Licorice Polysaccharides: Review

Licorice is known as "Gan-Cao" in traditional Chinese Medicine (TCM), belonging to the genus Glycyrrhiza (Family: Fabaceae/Leguminosae). It has a long medicinal history and wide applications in China. Polysaccharides of licorice (LPs) are one of the key bioactive components. As herbal polysaccharides attracted increasing interest in the past several decades, their extraction, isolation, structural characterization, pharmacological activities, and medicinal application have been explored extensively. It is worth heeding that the method of extraction and purification effects LPs, apart from specie and origin specificity. This review evaluates the method of extraction and purification and demonstrates its performance in gaining specific composition and its structure-activity relationship, which might lead the readers to a fresh horizon for developing advanced treatment strategies. It is recently reported that the conformation of LPs plays a vital role as biopolymers, such as selenized modification, microencapsulation, nanocomposite, liposome formulation, drug/hydrogel combinations, biosensor device, and synergistic effect with a vaccine. In addition, LPs showed a good thermodynamics profile, as these properties enable them to interact with additional supramolecular interaction by chemical modifications or copolymerization. Functional polymers that are responsive to various external stimuli, such as physical, chemical, and biological signals, are a promising study topic. Thus, LPs are emerging as a new biomaterial that can enhance intended formulation along exerting its inherent medicinal effects. It is hoped that this review will provide a basis for the utilization and further developments of licorice polysaccharides in the vast medium.

Effects of Glycyrrhiza Polysaccharides on Chickens' Intestinal Health and Homeostasis

The overuse of antibiotics in poultry farming causes the accumulation of drug residue in animals' bodies and the occurrence of antibiotic-resistant bacteria, which not only compromise animals' health but ultimately endanger human health. Thus, there is an urgent need for a novel poultry feed additive to substitute for excessive antibiotics. Glycyrrhiza polysaccharides (GPS) derived from Chinese licorice have shown promising immunomodulatory effects in previous studies. The present study investigated the pharmacological effects of GPS on poultry intestines to assess whether it can be used as a feed additive. The results show that GPS can increase production of sIgA, promote the secretion activity of goblet cells, alter the gut microbial composition and lead to changes in short-chain fatty acids. GPS also elevated both Th1 and Th2 immune responses by facilitating the expression of IL-2, IL-4, IL-1β, and IFN-γ while increasing the proportion of both CD4+ and CD8+ cells in the intestine. Moreover, the results of 16S rRNA gene sequencing showed that GPS could significantly change intestinal microbiota composition in the intestine, evidenced by the increased proportion of Bacteroides, Butyricicoccus and Eisenbergiella, as well as a decreased portion of Erysipelatoclostridium, leading to a healthier intestinal microbiota composition for the host. Taken together, it can be concluded that GPS is safe to use as a novel feed additive that can be used as an alternative to prophylactic antibiotics in poultry feeding.

Glycyrrhiza polysaccharides can improve and prolong the response of chickens to the Newcastle disease vaccine

Licorice is a medicinal and food plant widely used to treat diseases and produce food additives, because of its unique chemical constituents like polysaccharides, flavones, and saponins. Glycyrrhiza Polysaccharides (GPS-1) are water-soluble neutral polysaccharides extracted from licorice. Currently, GPS-1 is administrated to chickens by gavage every d for 14 d to observe the impact of GPS-1 on the Newcastle disease vaccine. To determine the immunity of these chickens to NDV, blood serum levels of hemagglutinin-inhibition (HI) antibody, and immunoglobulins IgA and IgG were measured. Meanwhile, the expression levels of cytokines IL-2, IL-4, IL-17, and IFN-γ were measured to evaluate the degree of immune booster activity. The chickens' spleen and peripheral blood lymphocytes displayed a significant increase in the proportion of CD4+ and CD8+ T cells after booster treatments with GPS-1. The results indicated that GPS-1 had a significant, dose-dependent, immune-boosting effect which could enhance NDV vaccine immunity in chickens.

The potential of glycyrrhizin and licorice extract in combating COVID-19 and associated conditions

BACKGROUND

Several recent studies have stated that glycyrrhizin and licorice extract are present in most traditional Chinese medicine formulas used against SARS-CoV-2 in China. Significant data are showing that glycyrrhizin and licorice extract have multiple beneficial activities in combating most features of SARS-CoV-2.

PURPOSE

The aim of current review was to highlight recent progresses in research that showed the evidence of the potential use of glycyrrhizin and licorice extract against COVID-19.

METHODOLOGY

We have reviewed the information published from 1979 to October 2020. These studies demonstrated the effects , use and safety of glycyrrhizin and icorice extract against viral infections,bacterial infections, inflammatory disorders of lung ( in vitro and in vivo).  These studies were collated through online electronic databases research (Academic libraries as PubMed, Scopus, Web of Science and Egyptian Knowledge Bank).

RESULTS

Pooled effect size of articles provides information about the rationale for using glycyrrhizin and licorice extract to treat COVID-19. Fifty studies demonstrate antiviral activity of glycyrrhizin and licorice extract. The most frequent mechanism of the antiviral activity is due to disrupting viral uptake into the host cells and disrupting the interaction between receptor- binding domain (RBD) of SARS-COV2 and ACE2 in recent articles. Fifty studies indicate that glycyrrhizin and licorice extract have significant antioxidant, anti-inflammatory and immunomodulatory effects. Twenty five studies provide evidence for the protective effect of glycyrrhizin and licorice extract against inflammation-induced acute lung injury and cardiovascular disorders.

CONCLUSION

The current study showed several evidence regarding the beneficial effects of glycyrrhizin and licorice extract in combating COVID-19. More randomized clinical trials are needed to obtain a precise conclusion.

Isolation, structural characterization, biological activity, and application of Glycyrrhiza polysaccharides: Systematic review

Glycyrrhiza, one of the most widely used Chinese herbal medicines, is a perennial plant with good medicinal value. Polysaccharides as one of the main bioactive components of Glycyrrhiza, mainly composed of arabinose, glucose, galactose, rhamnose, mannose, xylose, and galacturonic acid in different proportions and types of glycosidic bonds. Glycyrrhiza polysaccharides (GP) have many biological activities, such as anti-oxidation, immune regulation, anti-tumor, apoptosis, anti-microbial, anti-inflammatory and regulation of intestinal flora. In this paper, relevant articles on the isolations, structural characterizations, and biological activities of GP published in the last 15 years (2006-2020) were referred to for a systematic review of the species. A total of 947 articles were searched from the database including NCBI, Science Direct, Web of Science, and How Net, and 109 of them were cited on the summarization of the past scientific researches of the polysaccharides of Glycyrrhiza genus. We hope that this work may provide new insights for further study and development of Glycyrrhiza.

Effects of a complex mixture prepared from agrimonia, houttuynia, licorice, peony, and phellodendron on human skin cells

Active ingredients derived from natural sources are widely utilized in many industries. Cosmetic active ingredients are largely derived from various plants. In this study, we examined whether a mixture of plant extracts obtained from agrimonia, houttuynia, licorice, peony, and phellodendron (hereafter AHLPP), which are well-known for their effects on skin, could affect skin barrier function, inflammation, and aging in human skin cells. We also determined whether AHLPP extracts sterilized using γ-irradiation (to avoid preservatives) retained their skin cell regulating activity. The AHLPP mixture could downregulate representative pro-inflammatory cytokines including IL 1-β and IL 7. Procollagen peptide synthesis was also increased by AHLPP treatment along with mRNA upregulation of barrier proteins such as filaggrin and desmoplakin. The AHLPP mixture showed an anti-aging effect by significantly upregulating telomerase activity in human keratinocytes. We further observed TERT upregulation and CDKN1B downregulation, implying a weakening of pro-aging signal transduction. Co-cultivation of a hydrogel polymer containing the AHLPP mixture with human skin cells showed an alteration in skin-significant genes such as FLG, which encodes filaggrin. Thus, the AHLPP mixture with or without γ-irradiation can be utilized for skin protection as it alters the expression of some significant genes in human skin cells.

Increased antioxidant activity and improved structural characterization of sulfuric acid-treated stepwise degraded polysaccharides from Pholiota nameko PN-01

The aim of this study was to investigate sulfuric acid degradation of the Pholiota nameko polysaccharide (AIPS-1). Three stepwise degraded polysaccharides (AIPS-2, AIPS-3, and AIPS-4) were obtained by sequentially increasing the strength of sulfuric acid treatment. Structural characterization showed that sulfuric acid treatment significantly decreased molecular weight, increased the content of uronic acid and changed the molar ratio of monosaccharide composition, while the major functional groups and the triple helical conformation of polysaccharides did not change significantly. In vitro experiments proved that the antioxidation ability of the stepwise degraded polysaccharides gradually increased (AIPS-1 < AIPS-2 < AIPS-3 < AIPS-4). An oxidative stress zebrafish model was established, which demonstrated that the ability of AIPS-3 and AIPS-4 to scavenge free radicals in zebrafish was significantly improved compared to AIPS-1. In conclusion, sulfuric acid treatment is an effective method for improving the antioxidant activity of polysaccharides, and increased antioxidant activity was closely related to the changes in their structural characteristics.

Extraction of polysaccharides from maca: Characterization and immunoregulatory effects on CD4+ T cells

The immunomodulatory effects of maca polysaccharides (MCPs) on macrophages have been demonstrated in many studies. However, the effects of MCPs on CD4⁺ T cells have not been studied. Four water-soluble MCPs, labeled MCP1 (weight-average molecular weights [Mws] of 896.1 and 276.6 kDa), MCP2 (Mws of 337.8 and 219.0 kDa), MCP3 (Mws of 110.6, 58.1, and 38.9 kDa), and MCP4 (Mws of 15.7, 12.6, and 12.1 kDa), were obtained from maca by graded ethanol precipitation. The immunoregulatory effects of MCPs on CD4⁺ T cells were evaluated for the first time. The experimental results indicated that all MCPs had immunoregulatory effects on CD4⁺ T cells. However, the effects of MCP2 were stronger compared to the other three components, not only in promoting the proliferation of CD4⁺ T cells but also in terms of secretion of interferon-γ (IFN-γ). The molecular weight and monosaccharide compositions of MCPs were analyzed to explore the structure-activity relationship. The results suggested that the molecular weight and the galactosamine (GalN) of MCPs might be determining factors for its bioactivity. These findings suggest that the MCP2 isolated in our study have immune potentiation effects on CD4⁺ T cells.