Polysaccharide Derived from Nelumbo nucifera Lotus Plumule Shows Potential Prebiotic Activity and Ameliorates Insulin Resistance in HepG2 Cells

Preparation, structural characterization, and biological activities of lotus polysaccharides: A review

Lotus (Nelumbo nucifera), belonging to the family of Nelumbonaceae, is a beautiful aquatic perennial plant. It has been used as an ancient horticulture plant and famous agricultural crop for thousands of years. Modern phytochemical and pharmacological experiments have proved that polysaccharide is one of the most pivotal bioactive constituents of lotus. Hence, the systematic review covering the fundamental research advances and developing prospects of N. nucifera polysaccharides (NNPs) is an urgent demand to provide theoretical basis for their further research and application. The present review summarizes current emerging research progresses on the polysaccharides isolated from lotus, and it focuses on advanced extraction and purification methods, unique structural features, engaging biological activities, potential molecular mechanisms, as well as the relationship of structure and activity of NNPs. This review sheds light on the potential values of NNPs in affording functionally bioactive agents in food industry or therapeutically effective medicines for health care. In addition, this review will provide valuable insights for further commercial product development and promising industrial application of NNPs in both of the fundamental research communities and food or pharmaceutical industries in future.

Antioxidant and anti-melanogenesis activities of extracts from Leonurus japonicus Houtt

Leonurus japonicus Houtt is an important anti-skin pigmentation herb used in traditional Chinese medicine. However, the molecular basis for this activity is complex and not fully understood. In this study, water and ethanol extracts and polysaccharide extract from L. japonicus (LJPs) were analyzed by LC-MS/MS and HPLC-DAD separately. Cytotoxicity was analyzed by using CCK-8, antioxidant activity using flow cytometer, anti-MMPs, anti-tyrosinase and signalling pathway analysis using Western blotting to investigate their anti-melanogenesis function. The results showed that the water and ethanol extracts contained alkaloids, flavonoids, and phenolic acids. The LJPs mainly contain glucose, fucose, glucuronic acid, mannose, threonine and arginine, and structure characterization by FITR analyses indicated that LJPs have β- or α-D-glycosidic bonds and contain pyranose rings. The L. japonicus extracts displayed high cell viability at their maximum concentration. The water extract and polysaccharides significantly reduced lipopolysaccharide (LPS)-induced intracellular reactive oxygen species (ROS) content and exhibited a cytoprotective role. Also, these extracts displayed higher matrix metalloproteinase-2 (anti-MMP-2), anti-MMP-9 and anti-tyrosinase activities. Furthermore, the polysaccharides displayed significantly greater inhibitory effect on intracellular ROS and tyrosinase protein expression than α-arbutin and ursolic acid used for the clinical treatment of skin pigmentation. This study also investigated the polysaccharide inhibition of melanin synthesis by repressing the expression of melanocytic lineage-specific transcription factor (MITF) and melanogenic enzymes via modulation of the phosphoinositide 3-kinase (PI3K-Akt-mTOR) and β-catenin pathways. The overall results indicate that L. japonicus is a promising candidate for anti-pigmentation treatment.

Recent advances in medicinal and edible homologous plant polysaccharides: Preparation, structure and prevention and treatment of diabetes

Medicinal and edible homologs (MEHs) can be used in medicine and food. The National Health Commission announced that a total of 103 kinds of medicinal and edible homologous plants (MEHPs) would be available by were available in 2023. Diabetes mellitus (DM) has become the third most common chronic metabolic disease that seriously threatens human health worldwide. Polysaccharides, the main component isolated from MEHPs, have significant antidiabetic effects with few side effects. Based on a literature search, this paper summarizes the preparation methods, structural characterization, and antidiabetic functions and mechanisms of MEHPs polysaccharides (MEHPPs). Specifically, MEHPPs mainly regulate PI3K/Akt, AMPK, cAMP/PKA, Nrf2/Keap1, NF-κB, MAPK and other signaling pathways to promote insulin secretion and release, improve glycolipid metabolism, inhibit the inflammatory response, decrease oxidative stress and regulate intestinal flora. Among them, 16 kinds of MEHPPs were found to have obvious anti-diabetic effects. This article reviews the prevention and treatment of diabetes and its complications by MEHPPs and provides a basis for the development of safe and effective MEHPP-derived health products and new drugs to prevent and treat diabetes.

Pectin from Citrus unshiu Marc. Alleviates Glucose and Lipid Metabolism by Regulating the Gut Microbiota and Metabolites

The effects of pectin from Citrus unshiu Marc. on glycolipid metabolism, the morphologies of the pancreas and epididymal fat, the gut microbiota, and the metabolites of short-chain fatty acids (SCFAs) in db/db mice were investigated in this study. The results indicated that pectin reduced the levels of fasting blood glucose, glycated serum protein, triglycerides, total cholesterol, and low-density lipoprotein cholesterol while increasing the levels of high-density lipoprotein cholesterol. Meanwhile, pectin could improve the morphology of islet cells and inhibit the hypertrophy of adipocytes. Additionally, pectin not only regulated the intestinal flora dysbiosis in db/db mice, as shown by the increasing proportion of Firmicutes/Bacteroidetes and the relative abundance of Ligilactobacillus, Lactobacillus, and Limosilactobacillus, but also remedied the metabolic disorder of SCFAs in db/db mice. These results suggest that pectin could promote glucose and lipid metabolism by regulating the intestinal flora with changes in SCFA profile. This study proves that pectin might serve as a new prebiotic agent to prevent the disorder of glycolipid metabolism.

A review on extraction, composition, structure, and biological activities of polysaccharides from different parts of Nelumbo nucifera

Nelumbo nucifera (lotus plant) is an important member of the Nelumbonaceae family. This review summarizes the studies conducted on it since the past 15 years to provide an understanding on future areas of focus. Different parts of this plant, that is, leaves, roots, and seeds, have been used as food and for the treatment of various diseases. Polysaccharides have been extracted from different parts using different methods. The manuscript reviews the methods of extraction of polysaccharides used for leaves, roots, and seeds, along with their yield. Some methods can provide better yield while some provide better biological activity with low yield. The composition and structure of extracted polysaccharides have been determined in some studies. Although monosaccharide composition has been determined in various studies, too little information about the structure of polysaccharides from N. nucifera is available in the current literature. Different useful biological activities have been explored using in vivo and in vitro methods, which include antioxidant, antidiabetic, antitumor, anti-osteoporotic, immunomodulatory, and prebiotic activities. Antitumor activity from polysaccharides of lotus leaves is yet to be explored, besides lotus root has been underexplored as compared to other parts (leaves and seeds) according to our literature survey. Studies dedicated to the successful use of combination of extraction methods can be conducted in future. The plant provides a therapeutic as well as nutraceutical potential; however, antimicrobial activity and synergistic relationships of polysaccharides from different parts of the plant need further exploration.

Bioactive polysaccharides from lotus as potent food supplements: a review of their preparation, structures, biological features and application prospects

Lotus is a famous plant of the food and medicine continuum for millennia, which possesses unique nutritional and medicinal values. Polysaccharides are the main bioactive component of lotus and have been widely used as health nutritional supplements and therapeutic agents. However, the industrial production and application of lotus polysaccharides (LPs) are hindered by the lack of a deeper understanding of the structure-activity relationship (SAR), structural modification, applications, and safety of LPs. This review comprehensively comments on the extraction and purification methods and structural characteristics of LPs. The SARs, bioactivities, and mechanisms involved are further evaluated. The potential application and safety issues of LPs are discussed. This review provides valuable updated information and inspires deeper insights for the large scale development and application of LPs.

Managing metabolic diseases: The roles and therapeutic prospects of herb-derived polysaccharides

Metabolic diseases have become a public health problem worldwide. Effective, novel and natural therapies are urgently needed to treat metabolic diseases. As natural bioactive compounds, polysaccharides have many physiological and medicinal properties. Recently, herb-derived polysaccharides have shown beneficial effects in the treatment of metabolic diseases, but the underlying mechanisms remain unclear. This review comprehensively summarizes the pharmacological progress and clinical evidence of herb-derived polysaccharides in the treatment of three metabolic diseases, namely type 2 diabetes mellitus, nonalcoholic fatty liver disease and obesity, and more importantly, discusses the molecular mechanism involved. Existing evidence has proved that herb-derived polysaccharides can maintain glucose homeostasis, promote insulin secretion, improve insulin resistance, reduce weight gain and hepatic steatosis, inhibit lipogenesis, alleviate oxidative stress and inflammation, and improve gut microbiota disorders in rodents with metabolic diseases. Notably, so far, human clinical trials of herb-derived polysaccharides for these three metabolic diseases remain rare. All in all, herb-derived polysaccharides may have good potential as drug candidates for the prevention and management of metabolic diseases. More high-quality clinical trials are needed to further validate its effectiveness and safety in human subjects.

Extraction, purification, structural characteristics, biological activities, and application of the polysaccharides from Nelumbo nucifera Gaertn. (lotus): A review

Nelumbo nucifera Gaertn. (lotus) is a widely distributed plant with a long history of cultivation and consumption. Almost all parts of the lotus can be used as foodstuff and nourishment, or as an herb. It is noteworthy that the polysaccharides obtained from lotus exhibit surprisingly and satisfying biological activities, which explains the various benefits of lotus to human health, including anti-diabetes, anti-osteoporosis, antioxidant, anti-inflammatory, anti-tumor, etc. Here, we systematically review the recent major studies on extraction and purification methods of polysaccharides from different parts (rhizome, seed, leaf, plumule, receptacle and stamen) of lotus, as well as the characterization of their chemical structure, biological activity and structure-activity relationship, and the applications of lotus polysaccharides in different fields. This article will give an updated and deeper understanding of lotus polysaccharides and provide theoretical basis for their further research and application in human health and manufacture development.

Preparation, Characterization, and Anti-Adhesive Activity of Sulfate Polysaccharide from Caulerpa lentillifera against Helicobacter pylori

In the gastric mucosa, chronic inflammation due to Helicobacter pylori infection promotes gastrocarcinogenesis. Polysaccharides of Caulerpa lentillifera are well-characterized by broad antimicrobial activity and anti-inflammatory potentials. The present study was undertaken to investigate whether the low molecular sulfate polysaccharides of C. lentillifera (CLCP) exhibit any anti-adhesive activity against H. pylori. After a hot water extraction and purification process, two purified polysaccharide fractions (CLCP-1 and CLCP2) were studied based on structural characterization and bioactivity determination. The results implied that except for the molar ratio, CLCP-1 and CLCP-2 contain high sulfate, mannose, galactose, xylose, glucose levels, and low protein levels. The molecular weight and Fourier transform infrared spectroscopy (FT-IR) assays confirmed that CLCP-1 and CLCP-2 are sulfate polysaccharides with an average molecular weight (Mw) of 963.15 and 648.42 kDa, respectively. In addition, CLCP-1 and CLCP-2 exhibited stronger antibacterial activity against H. pylori. CLCP-1 and CLCP-2 could significantly promote macrophage proliferation and decrease the production of nitric oxide (NO) through downregulated expression of inducible nitric oxide synthase (iNOS). Meanwhile, CLCP-1 and CLCP-2 in this study showed efficiently protected gastric adenocarcinoma (AGS) cells against H. pylori with the inhibition of the IL-8/NF-κB axis. These findings suggested the effect of Caulerpa lentillifera polysaccharides on H. pylori adhesion, a potential supply of nutrients for eradication therapy through the reduction of cell count and inflammation.

Extraction optimization, physicochemical property, antioxidant activity, and α-glucosidase inhibitory effect of polysaccharides from lotus seedpods

BACKGROUND

Lotus seedpods are an agricultural by-product of lotus (Nelumbo nucifera Gaertn.), which is widely cultivated in Southeast Asia and Australia. Most lotus seedpods are considered waste and are abandoned or incinerated, resulting in significant waste of resources and heavy environmental pollution. For recycling lotus seedpods, the extraction optimization, physicochemical properties, antioxidant activity, and α-glucosidase inhibitory effect of the polysaccharides contained therein were investigated in this study.

RESULTS

Hot water extraction of lotus seedpod polysaccharides was optimized by using a response surface methodology combined with a Box-Behnken design, with the optimum conditions being as follows: a liquid/solid ratio of 25.0 mL g^-1 , an extraction temperature of 98.0 °C, and an extraction time of 138.0 min. Under these conditions, an experimental yield of 5.88 ± 0.06% was obtained. Physicochemical analyses suggested that lotus seedpod polysaccharides belong to acidic heteropolysaccharides and are principally composed of rhamnose, arabinose, galactose, glucose, mannose, and galacturonic acid. The polysaccharides content has a broad molecular weight distribution (2.15 × 10⁵ to 1.77 × 10⁷  Da), an α-configuration, and mainly possesses smooth and sheet-like structures. Biological evaluations showed that the polysaccharides possessed good scavenging activity on 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, 1,1-diphenyl-2-picryl-hydrozyl, and hydroxyl radicals, and exerted an obvious inhibitory effect on α-glucosidase activity. Moreover, the polysaccharides content was determined to be a mixed-type noncompetitive inhibitor of α-glucosidase.

CONCLUSION

The results indicate that lotus seedpod polysaccharides have potential as natural antioxidants and hypoglycaemic substitutes. This study provides the theoretical bases for the exploitation and application of polysaccharides from lotus seedpod by-product resources. © 2022 Society of Chemical Industry.

A Review on the Extraction, Bioactivity, and Application of Tea Polysaccharides

Tea is a non-alcoholic drink containing various active ingredients, including tea polysaccharides (TPSs). TPSs have various biological activities, such as antioxidant, anti-tumor, hypoglycemic, and anti-cancer activities. However, TPSs have a complex composition, which significantly limits the extraction and isolation methods, thus limiting their application. This paper provides insight into the composition, methodological techniques for isolation and extraction of the components, biological activities, and functions of TPSs, as well as their application prospects.

Flavonoids from Sacred Lotus Stamen Extract Slows Chronological Aging in Yeast Model by Reducing Oxidative Stress and Maintaining Cellular Metabolism

Nelumbo nucifera is one of the most valuable medicinal species of the Nelumbonaceae family that has been consumed since the ancient historic period. Its stamen is an indispensable ingredient for many recipes of traditional medicines, and has been proved as a rich source of flavonoids that may provide an antiaging action for pharmaceutical or medicinal applications. However, there is no intense study on antiaging potential and molecular mechanisms. This present study was designed to fill in this important research gap by: (1) investigating the effects of sacred lotus stamen extract (LSE) on yeast lifespan extension; and (2) determining their effects on oxidative stress and metabolism to understand the potential antiaging action of its flavonoids. A validated ultrasound-assisted extraction method was also employed in this current work. The results confirmed that LSE is rich in flavonoids, and myricetin-3-O-glucose, quercetin-3-O-glucuronic acid, kaempferol-3-O-glucuronic acid, and isorhamnetin-3-O-glucose are the most abundant ones. In addition, LSE offers a high antioxidant capacity, as evidenced by different in vitro antioxidant assays. This present study also indicated that LSE delayed yeast (Saccharomyces cerevisiae, wild-type strain DBY746) chronological aging compared with untreated control yeast and a positive control (resveratrol) cells. Moreover, LSE acted on central metabolism, gene expressions (SIR2 and SOD2), and enzyme regulation (SIRT and SOD enzymatic activities). These findings are helpful to open the door for the pharmaceutical and medical sectors to employ this potential lotus raw material in their future pharmaceutical product development.

Validation of a High-Performance Liquid Chromatography with Photodiode Array Detection Method for the Separation and Quantification of Antioxidant and Skin Anti-Aging Flavonoids from Nelumbo nucifera Gaertn. Stamen Extract

Nelumbo nucifera Gaertn., or the so-called sacred lotus, is a useful aquatic plant in the Nelumbonaceae family that has long been used to prepare teas, traditional medicines as well as foods. Many studies reported on the phytochemicals and biological activities of its leaves and seeds. However, to date, only few studies were conducted on its stamen, which is the most important ingredient for herbal medicines, teas and other phytopharmaceutical products. Thus, this present study focuses on the following: (1) the application of high-performance liquid chromatography with photodiode array detection for a validated separation and quantification of flavonoids from stamen; (2) the Nelumbo nucifera stamen’s in vitro and in cellulo antioxidant activities; as well as (3) its potential regarding the inhibition of skin aging enzymes for cosmetic applications. The optimal separation of the main flavonoids from the stamen ethanolic extract was effectively achieved using a core-shell column. The results indicated that stamen ethanolic extract has higher concentration of in vitro and in cellulo antioxidant flavonoids than other floral components. Stamen ethanolic extract showed the highest protective effect against reactive oxygen/nitrogen species formation, as confirmed by cellular antioxidant assay using a yeast model. The evaluation of potential skin anti-aging action showed that the stamen extract has higher potential to inhibit tyrosinase and collagenase compared with its whole flower. These current findings are the first report to suggest the possibility to employ N. nucifera stamen ethanolic extract as a tyrosinase and collagenase inhibitor in cosmetic applications, as well as the utility of the current separation method.

Phytochemical Diversity and Antioxidant Potential of Natural Populations of Nelumbo nucifera Gaertn. throughout the Floristic Regions in Thailand

Asian lotus has long been consumed as a food and herbal drug that provides several health benefits. The number of studies on its biological activity is significant, but research at the population level to investigate the variation in phytochemicals and biological activity of each population which is useful for a more efficient phytopharmaceutical application strategy remains needed. This present study provided the frontier results to fill-in this necessary gap to investigating the phytopharmaceutical potential of perianth and stamen, which represent an important part for Asian traditional medicines, from 18 natural populations throughout Thailand by (1) determining their phytochemical profiles, such as total contents of phenolic, flavonoid, and anthocyanin, and (2) determining the antioxidant activity of these natural populations using various antioxidant assays to examine different mechanisms. The result showed that Central is the most abundant floristic region. The stamen was higher in total phenolic and flavonoid contents, whereas perianth was higher in monomeric anthocyanin content. This study provided the first description of the significant correlation between phytochemical contents in perianth compared with stamen extracts, and indicated that flavonoids are the main phytochemical class. This analysis indicated that the stamen is a richer source of flavonoids than perianth, and provided the first report to quantify different flavonoids accumulated in stamen and perianth extracts under their native glycosidic forms at the population level. Various antioxidant assays revealed that major flavonoids from N. nucifera prefer the hydrogen atom transfer mechanism when quenching free radicals. The significant correlations between various phytochemical classes and the different antioxidant tests were noted by Pearson correlation coefficients and emphasized that the antioxidant capability of an extract is generally the result of complex phytochemical combinations as opposed to a single molecule. These current findings offer the alternative starting materials to assess the phytochemical diversity and antioxidant potential of N. nucifera for phytopharmaceutical sectors.

Potential hypoglycemic, hypolipidemic, and anti-inflammatory bioactive components in Nelumbo nucifera leaves explored by bioaffinity ultrafiltration with multiple targets

Leaf of Nelumbo nucifera Gaertn. (N. nucifera) has been widely used as the main ingredient in lipid-lowering herbal teas and some prescriptions in China due to their excellent hypoglycemic and hypolipidemic effects. However, the active components responsible for these beneficial properties and their mechanisms remain unexplored. In this work, the N. nucifera leaf extracts significantly promoted the glucose consumption of HepG2 cells, and also exhibited remarkable inhibitory activities against α-glucosidase, pancreatic lipase, and COX-2. Furthermore, the top four potential active compounds (N-nornuciferine, Nuciferine, 2-Hydroxy-1-methoxyaporphine, and Isorhamnetin 3-O-glucoside) targeting the above three enzymes were screened out by bioaffinity ultrafiltration with multiple targets coupled with HPLC-MS/MS. The enzyme inhibitory activities of candidate compounds were verified by enzyme inhibition assay and molecular docking. In addition, molecular docking revealed the binding information between the candidate molecules and enzymes. The current study provided valuable information in discovering functional active ingredients from complex medicinal plant extracts.