Nelumbo Nucifera Research Articles

Non-Covalent Interactions of Lotus Root Polysaccharides and Polyphenols and their Regulatory Mechanism on Macrophage Functions

Despite the interaction between polyphenols and polysaccharides in food products, their specific non-covalent interactions and effects on macrophage functions are not well understood. Therefore, the interaction and mechanism of purified lotus root polysaccharide (PLRP) with polyphenols, and the regulatory mechanisms of the PLRP-polyphenol complex on the macrophage functionals were studied. By combining ferulic acid (FA) and chlorogenic acid (CHA) with PLRP, the complexes PLRP-FA, PLRP-CHA and the physical mixtures PLRP&FA and PLRP&CHA were prepared, where their mass ratios of polyphenols to PLRP were 143.97 and 601.67 mg g−1. Nuclear magnetic resonance (NMR), Fourier-transform infrared (FTIR), Ultraviolet (UV), and Transmission electron microscopy (TEM) analyses confirmed that PLRP and polyphenols may engage in non-covalent interactions via hydrogen bonds and hydrophobic interactions. We confirmed that non-covalent interactions led to high molecular weight, dense complexes. Both PLRP and its polyphenol complexes stimulated NO production by macrophages to varying degrees without exacerbating lipopolysaccharide-induced inflammatory responses. PLRP and PLRP-polyphenol complexes repaired cells with impaired antioxidant capacity, depending on doses. Those results indicated that after the combination of lotus root polysaccharide and polyphenol, the molecular weight and conformation changed significantly, which influenced the biological activity. RNA-seq analysis suggested that the regulatory mechanism of PLRP-polyphenol complex in macrophages may mainly involve oxidative phosphorylation, FoxO, TNF, IL-17, MAPK, NF-kappa B, and other signaling pathways. This study investigated the effects of polyphenol binding on the physicochemical characteristics and functional activities of polysaccharides, which provided references for the development of polysaccharide functional products and the control of nutritional quality.

Structural changes in Nelumbo flower petals during opening and closing.

Nelumbo nucifera is one of several plant species with flowers that typically open in the early morning and close by noon. This movement normally repeats for 3 days, with all petals falling off on day 4. However, detailed observations of flower movement in Nelumbo species are limited. Movement of flowers on plants in growth chambers were observed using time-lapse photography. Petals were examined with scanning electron microscopy or fixed and sectioned for light microscopy to determine whether changes in cell size contribute to petal elongation during flowering. This study is the first to microscopically observe petal cells of a Nelumbo species during flowering in controlled conditions. Petals elongated during the 4-day flowering period. Inner petals were more elongated than the outer petals. Among the basal, central, and tip regions of a single petal, the cells in the basal region enlarged the most. Outer and inner epidermal cells in the basal region of the inner petals, on both adaxial and abaxial sides, gradually enlarged during the flowering period through cycles of repeated increases as the petals opened and decreases as they closed. Petals opened and closed repeatedly as they elongated, primarily in their basal region. Cells in the basal region of the petal on the adaxial and abaxial sides periodically fluctuated in size, increased during flower opening and decreased during closing, but differences in these patterns were observed between the two sides, suggesting that one of the driving forces behind the opening and closing of flowers of Nelumbo species is the increase and decrease in the size of the petal cells.

Quality Characteristics and Antioxidant Activity of Soup Supplemented with Lotus Root Powder

Quality Characteristics and Antioxidant Activity of Soup Supplemented with Lotus Root Powder

C-13 Norisoprenoids and Eudesmanoids from Nelumbo nucifera Gaertn. Regulate the Lipid Metabolism via the AMPK/ACC/SREBP-1c Signaling Pathway.

Lotustine A (1), an undescribed C-13 norisoprenoid, along with 22 known analogues and two eudesmanoids, were isolated from the aerial parts of Nelumbo nucifera Gaertn. Among them, compounds 2, 15, 17, 21, 22, 24, 25 were isolated from N. nucifera leaves for the first time. Their structures, including absolute configurations, were elucidated by nuclear magnetic resonance, mass spectroscopy, and the modified Mosher's method. Compound 1 is the first example of C-13 norisoprenoid with a terminal double bond between C-5 and C-13. Moreover, the lipid-lowering activities of the isolates were evaluated, and the results showed that 2, 24 and 25 could remarkably decrease the levels of both total cholesterol and triglyceride in free fatty acids induced HepG2 cells at the concentration of 20 μM. The oil red staining assay further demonstrated the lipid-lowering effects of 2, 24 and 25. The western blot results indicated that compounds 2, 24 and 25 could regulate the lipid metabolism via the activation of the AMPK/ACC/SREBP-1c signaling pathway.

Genetic Diversity of Lotus (Nelumbo nucifera Gaertn.) Genotypes Assessed by Random Amplified Polymorphic DNA Markers

Genetic Diversity of Lotus (Nelumbo nucifera Gaertn.) Genotypes Assessed by Random Amplified Polymorphic DNA Markers

Nuciferine Alleviates High-Fat Diet- and ApoE-/--Induced Hepatic Steatosis and Ferroptosis in NAFLD Mice via the PPARα Signaling Pathway.

Nonalcoholic fatty liver disease (NAFLD) causes significant global mortality and healthcare costs with no recommended pharmacological intervention for clinical management. Nuciferine (Nuc) is an alkaloid with aromatic rings, abundantly found in Nelumbo nucifera Gaertn. In this study, we explored the protective mechanisms of Nuc against hepatic steatosis and ferroptosis in NAFLD. High-fat diet (HFD) and healthy male ApoE-/- mice were used to induce NAFLD and a hypercholesterolemia model. Nuc was administered to the mice for four consecutive weeks from the ninth week. Various assessments, including histopathology, RNA sequencing, lipid metabolism, and ferroptosis-related protein expression, showed that Nuc alleviated hepatic steatosis and ferroptosis. We further showed that Nuc improves fatty acid accumulation and ferroptosis through the PPARα signaling pathway in mice and RSL3-treated AML-12 cells. The PPARα inhibitor GW6471 blocked Nuc's protective effects, leading to excess accumulation of iron ions. Thus, Nuc may be a potential therapeutic agent for NAFLD.

Study on Quality and Starch Characteristics of Powdery and Crispy Lotus Roots.

Nine varieties of lotus root (Suining, Xinhe, Zaohua, Zhonghua, L0014, L0013, Cuiyu, L0011, and Zhenzhu) were selected as the research materials to compare their differences in physical, chemical, and starch characteristics before and after boiling, frying, and microwaving. The results showed that Zhenzhu, Xinhe, L0013, Cuiyu, and Zhonghua belong to the crispy lotus root type, while L0011, L0014, Zaohua, and Suining belong to the powdery lotus root type. Furthermore, the nine varieties were characterized for their starch by optical micrograph (OM), polarized micrograph (PM), scanning electron micrograph (SEM), attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), carbon-13 cross-polarization/magic angle spinning nuclear magnetic resonance (13C CP/MAS NMR), and differential scanning calorimetry (DSC). The starch granule of powdery lotus root appeared to be larger than that of crispy lotus, and ATR-FTIR studies revealed that the outer layer of starch granules from nine different varieties of lotus root had a highly organized structure. Moreover, XRD and 13C CP/MAS NMR analyses revealed that starch from eight lotus varieties (Suining, Xinhe, Zaohua, Zhonghua, L0014, L0013, Cuiyu, L0011) belong to the A-crystal type, while starch from Zhenzhu belongs to the CA-crystal type. The starch from powdery lotus root exhibited higher crystallinity, as well as increased gelatinization temperature and enthalpy, indicating that its crystal structure was relatively superior compared to that of crispy lotus starch. The short-range order degree, crystallinity, gelatinization temperature, and heat enthalpy of lotus starch decreased after boiling and frying but increased to varying extents after microwaving. Additionally, the heat resistance and stability of starch particles from crispy lotus root were improved after microwave treatment.

Cell wall remodeling confers plant architecture with distinct wall structure in Nelumbo nucifera.

Lotus (Nelumbo nucifera G.) is a perennial aquatic horticultural plant with diverse architectures. Distinct plant architecture (PA) has certain attractive and practical qualities, but its genetic morphogenesis in lotus remains elusive. In this study, we employ genome-wide association analysis (GWAS) for the seven traits of petiole length (PLL), leaf length (LL), leaf width (LW), peduncle length (PLF), flower diameter (FD), petal length (PeL), and petal width (PeW) in 301 lotus accessions. A total of 90 loci are identified to associate with these traits across 4 years of trials. Meanwhile, we perform RNA sequencing (RNA-seq) to analyze the differential expression of the gene (DEG) transcripts between large and small PA (LPA and SPA) of lotus stems (peduncles and petioles). As a result, eight key candidate genes are identified that are all primarily involved in plant cell wall remodeling significantly associated with PA traits by integrating the results of DEGs and GWAS. To verify this result, we compare the cell wall compositions and structures of LPA versus SPA in representative lotus germplasms. Intriguingly, compared with the SPA lotus, the LPA varieties have higher content of cellulose and hemicellulose, but less filling substrates of pectin and lignin. Additionally, we verified longer cellulose chains and higher cellulose crystallinity with less interference in LPA varieties. Taken together, our study illustrates how plant cell wall remodeling affects PA in lotus, shedding light on the genetic architecture of this significant ornamental trait and offering a priceless genetic resource for future genomic-enabled breeding.

Enhanced antioxidant activities, polyphenols, flavonoids, and free amino acid contents of Nelumbo nucifera bee pollen via high hydrostatic pressure treatment

ABSTRACT The aim of the present study was to address the effect of high hydrostatic pressure (HHP) on bioactive compounds and antioxidant activity of Nelumbo nucifera (Lotus) bee pollen (LBP). The total phenolic contents (TPC) and free amino acids were determined and flavonoid composition was identified by UPLC-Triple-TOF-MS. Five analytical methods including DPPH, ABTS, reducing power, FRAP, and silver nanoparticles antioxidant capacity were used for the antioxidant activity analysis. The results revealed a significant increase in the TPC and free amino acid compositions after HHP treatment. The DPPH, ABTS, reducing power, FRAP, and AgNPAC of the extracted fractions were augmented by over 13.94, 2.9, 2.68, 85, and 2.6 times, respectively. PCA analysis showed a strong correlation between TPC, some distinct flavonoids, and antioxidant activities. These results indicated that HHP enhances the antioxidant activity of LBP via increase in amino acids, TPC, and some flavonoids such as Licoagrone, Kuwanon K, Cyanidin 3-rutinoside, etc.

Lotus growth and development in artificial water bodies in the conditions of the Stavropol Upland

Relevance. The creation of a botanical collection of the lotus family made it possible to study the biology and adaptive features of a rare relict species of Nelumbo nucifera and its variety in the conditions of the Stavropol Upland.Methods. The main phases of development (the beginning of growth, budding, flowering) were recorded. Statistical processing was carried out by the method of variance analysis according to G.N. Zaitsev.Results. In 2010, Nelumbo nucifera seeds were purchased from the Volga River Delta and planted in a 100-liter container, which was located in a closed ground. From 2010 to 2014, the plant vegetated every year from the second decade of January to November, in November, vegetation was artificially stopped. With such agricultural techniques, the plant had no flowering and fruiting phases. In June 2014, rhizomes were planted and lotus seeds were sown in a pond made of butyl rubber film. In 2017, the first flowering was observed. During the study period, the plants did not reach natural indicators, on average, the diameter of the leaves is less by 18.5 ± 1.6 cm, the flowers are 2 ± 0.1 cm, the height is 1.0–1.5 m. The duration of flowering is 57 ± 4 days, which corresponds to the natural conditions of lotus growth from mid-July to early September. During the years of research, 495 seeds were obtained. Under the influence of abiotic factors, the nut-bearing lotus lives up to 8 years in the botanical garden. Nelumbo nucifera Betsy grows intensively, flowering occurred in the third year after sowing, leaf diameter 57 ± 3 cm, height above the water surface 78 ± 7 cm, flowering duration 73 ± 7 days, which is longer than that of the nut-bearing lotus, full-fledged seeds are formed.

Multivariate genetic analysis and diversity assessment in lotus (Nelumbo nucifera) accessions

The present study was carried out during 2019 to 2022 at the Floriculture Research Station (Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu), Thovalai, Kanyakumari, Tamil Nadu to access the genetic variability in lotus accessions (Nelumbo nucifera) collected from 6 diverse locations. The research presents significant insights into the growth and flowering characteristics of these extraordinary aquatic plants and their adaptability to various environmental conditions. The analysis of mean performance showcases noteworthy variations in plant height, leaf dimensions, flowering time and the number of leaves, and flowers/plant across different collection sites, highlighting the profound influence of local environmental conditions on lotus growth. Lotus traits with significant genetic diversity and heritability, presenting opportunities for targeted selective breeding were identified. Principal component analysis uncovers key trait influencers, while cluster analysis categorizes accessions based on similarities, streamlining research and cultivation. Correlation and path analysis unveil relationships among lotus traits, enhancing our understanding of growth factors. D2 cluster composition reveals distinct groupings; Cluster I includes KNn1 and KNn5, Cluster II features KNn2, Cluster III comprises KNn6, Cluster IV contains KNn3, and Cluster V houses KNn4. Genetic divergence analysis identifies the number of flowers/plant as the primary driver of genetic diversity, emphasizing its importance for breeding. It underscores the need to consider both genetic and environmental factors in lotus cultivation and highlights the importance of targeted breeding efforts to unlock the full potential of lotus.

Characterization and Molecular Engineering of a N-Methyltransferase from Edible Nelumbo nucifera Leaves Involved in Nuciferine Biosynthesis.

Lotus leaf, traditionally used as both edible tea and herbal medicine in Asia, contains nuciferine, a lipid-lowering and weight-loss compoud. The biosynthetic pathways of nuciferine in Nelumbo nucifera remain unclear. We characterized a specific N-methyltransferase, NnNMT, which had a novel function and catalyzed only nuciferine synthesis from the aporphine-type alkaloid N-nornuciferine. The expression profile of NnNMT was in agreement with BIA accumulation patterns in four tissues from three varieties, suggesting that NnNMT is involved in nucleiferine biosynthesis in Nelumbo nucifera. Protein engineering based on molecular docking and dynamic simulations revealed key residues (Y98, H208, F256, Y81, F329, G260, P76, and H80) crucial for NnNMT activity, with the F257A mutant showing increased efficiency. These findings enhance our understanding of aporphine alkaloid biosynthesis and support the development of lotus-based functional foods and medicinal applications.

Dosage sensitivity shapes balanced expression and gene longevity of homoeologs after whole-genome duplications in angiosperms.

Following whole-genome duplication (WGD), duplicate gene pairs (homoeologs) can evolve varying degrees of expression divergence. However, the determinants influencing these relative expression level differences (RFPKM) between homoeologs remain elusive. In this study, we analyzed the RFPKM between homoeologs in 3 angiosperms, Nymphaea colorata, Nelumbo nucifera, and Acorus tatarinowii, all having undergone a single WGD since the origin of angiosperms. Our results show significant positive correlations in RFPKM of homoeologs among tissues within the same species, and among orthologs across these 3 species, indicating convergent expression balance/bias between homoeologous gene copies following independent WGDs. We linked RFPKM between homoeologs to gene attributes associated with dosage-balance constraints, such as protein-protein interactions, lethal-phenotype scores in Arabidopsis (Arabidopsis thaliana) orthologs, domain numbers, and expression breadth. Notably, homoeologs with lower RFPKM often had more interactions and higher lethal-phenotype scores, indicating selective pressures favoring balanced expression. Also, homoeologs with lower RFPKM were more likely to be retained after WGDs in angiosperms. Within Nelumbo, greater RFPKM between homoeologs correlated with increased cis- and trans-regulatory differentiation between species, highlighting the ongoing escalation of gene expression divergence. We further found that expression degeneration in 1 copy of homoeologs is inclined toward nonfunctionalization. Our research highlights the importance of balanced expression, shaped by dosage-balance constraints, in the evolutionary retention of homoeologs in plants.

Integration of Mitoflash and Time-Series Transcriptomics Facilitates Energy Dynamics Tracking and Substrate Supply Analysis of Floral Thermogenesis in Lotus.

The high biosynthetic and energetic demands of floral thermogenesis render thermogenic plants the ideal systems to characterize energy metabolism in plants, but real-time tracking of energy metabolism in plant cells remains challenging. In this study, a new method was developed for tracking the mitochondrial energy metabolism at the single mitochondria level by real-time imaging of mitochondrial superoxide production (i.e., mitoflash). Using this method, we observed the increased mitoflash frequencies in the receptacles of Nelumbo nucifera Gaertn. at the thermogenic stages. This increase, combined with the higher expression of antioxidant response-related genes identified through time-series transcriptomics at the same stages, shows us a new regulatory mechanism for plant redox balance. Furthermore, we found that the upregulation of respiratory metabolism-related genes during the thermogenic stages not only correlates with changes in mitoflash frequency but also underscores the critical roles of these pathways in ensuring adequate substrate supply for thermogenesis. Metabolite analysis revealed that sugars are likely one of the substrates for thermogenesis and may be transported over long distances by sugar transporters. Taken together, our findings demonstrate that mitoflash is a reliable tool for tracking energy metabolism in thermogenic plants and contributes to our understanding of the regulatory mechanisms underlying floral thermogenesis.

Physicochemical and bioactive modifications of lotus root polysaccharides associated with probiotic fermentation

The physicochemical properties and bioactivities of lotus root polysaccharides (LRP) were investigated by examining the effects of probiotic fermentation. Five polysaccharides, namely LRP, LRP-Pl, LRPRh, LRPPa, and LRPAc, were extracted from unfermented and fermented lotus roots using Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus paracasei and Lactobacillus acidophilus, respectively. The results revealed that the yield of LRP-Ac (3.28 %) was 3.34 times higher than that of LRP (0.98 %), with its total sugar content and glucose content in the monosaccharide composition being the highest among the five polysaccharides. Probiotic fermentation led to an increase in Mw, as well as alterations in surface morphology and glycosidic bonds of LRPs, depending on the bacterial strains. Moreover, the five polysaccharides showed differences in antioxidant, α-amylase/α-glucosidase inhibitory, prebiotic, and macrophage-stimulating activities. Specifically, LRP-Pl exhibited the strongest DPPH radical scavenging ability; LRP-Rh showed the highest ABTS radical scavenging ability along with FRAP capacities; LRP-Ac possessed the greatest α-glucosidase inhibitory as well as prebiotic activities. However, the fermented polysaccharides showed relatively weak macrophage-stimulating ability compared to unfermented ones. Finally, the structure-activity relationship analysis revealed a close correlation between the chemical composition, Mw, and monosaccharide composition of LRPs and their bioactivities. These results are useful for the preparation of high-value LRPs.

Heating alters the nutritional and antioxidant characteristics of lotus root

To investigate the impact of heating on the nutritional and antioxidant properties of lotus root, a comparative analysis was conducted between its heated and unheated whole powders. The whole powder of heated lotus root (HLRWP) exhibited a higher level of total soluble sugars but a lower level of free phenolic compounds compared to the whole powder of fresh lotus root (FLRWP). Meanwhile, they showed significant differences in metabolite composition encompassing phenolic compounds, flavonoids, amino acids, vitamins and lipids. The replacement of sugar and corn in the medium with 25% HLRWP effectively enhanced the activities of antioxidant enzymes (total superoxide dismutase and catalase), while reducing malonaldehyde content in Drosophila melanogaster males. The average, median and maximum lifespans of the fruit flies were extended by 35.90%, 23.49% and 24.00% respectively, accompanied by an improvement in climbing ability. Additionally, their resistance to oxidative stress induced by hydrogen peroxide or paraquat was enhanced. The antioxidant capacity of HLRWP in vivo was found to be obviously stronger compared to FLRWP, which may have a crucial association with the regulation of L-arginine and adenosine monophosphate levels. The results indicate that heating can enhance the nutritional quality of lotus root products by strengthening their antioxidant capacity.

Isolation, selection and identification of lactic bacteria from pickled salt lotus root in Giang Thanh district, Kien Giang province

The study was conducted to isolate, select, and identify the lactic acid bacteria strain with the highest lactic acid fermentation ability from pickled lotus root products in Giang Thanh district, Kien Giang province. From three samples of pickled lotus root collected in Giang Thanh district, 11 lactic acid bacteria strains were isolated and preliminarily identified through colony morphology and some biochemical reactions such as Gram staining and catalase reaction. The results of determining the fermentation type showed that all 11 isolated bacterial strains had a homomorphic fermentation type, the main fermentation product was lactic acid. Of which, strain D15 had the highest lactic acid content, reaching 1.87 mg/mL and had the highest biomass growth ability, with an OD600nm value of 0.947. The 16S rRNA gene sequence of strain D15 was determined with a molecular size of 1469 bp. Comparing the 16S rRNA gene sequence of strain D15 on the gene bank, it has a similarity level of 100% with some lactic acid bacteria strains of the species Lactobacillus plantarum and 99.68% when comparing with the 16S rRNA gene sequence of the standard strain Lactobacillus plantarum. Constructing a phylogenetic tree and evaluating the genetic relationship of strain D15, the standard strain Lactobacillus plantarum, and 9 strains with the highest similarity to strain D15 based on the 16S rRNA gene sequence. The results were classified into 2 large groups with a similarity level of 92%, in which strain D15 is in the same group as the standard strain Lactobacillus plantarum and also has a similarity level of 92%.

Identification of Bioactive Compounds by GC-MS of Nelumbo Nucifera Leaf Extract and Virtual Screening of EGFR/ VEGFR2 Dual Inhibitors

Identification of Bioactive Compounds by GC-MS of Nelumbo Nucifera Leaf Extract and Virtual Screening of EGFR/ VEGFR2 Dual Inhibitors

Structural characterization and immunoregulatory mechanism of a low-molecular-weight polysaccharide from lotus root

The extraction of polysaccharide from lotus root was highly homogenized, and the structure of the polysaccharide was not clear. Herein, we report a hot water method combined with α-amylase that was applied to extract lotus root polysaccharide. After purified, a lotus root polysaccharide fraction LP60-a with high purity and low molecule weight was obtained. Systematic characterization of the structure of LP60-a was achieved by monosaccharide composition, methylation and NMR analysis, showing that LP60-a was composed of α-1,6-glucan linked with a small amount of arabinogalactan. Conformational determination showed that LP60-a was a three-helix polysaccharide with random coil conformation. Furtherly, the immunomodulatory activities of LP60-a were investigated in RAW264.7 macrophages. The data indicated that LP60-a could enhance the proliferation and phagocytosis of macrophages significantly, and induce the expression of NO and TNF-α in macrophages without causing inflammation. Moreover, LP60-a promoted the phosphorylation of MAPK p38 and JNK, as well as NF-κB p65, indicating that LP60-a could activate RAW264.7 cells through MAPK and NF-κB signaling pathways. In conclusion, the results imply that LP60-a could enhance the immune function of macrophages, presenting a possibility to play a role as an immunomodulatory agent in dietary supplements.

Unlocking new drying potential for Lotus root: Ultrasonic osmotic dehydration and microwave hot air drying based on phenolic retention and microstructure

Unlocking the potential of advanced drying techniques is crucial for enhancing the quality and shelf life of lotus root. This study investigated the impact of Ultrasonic-assisted osmotic dehydration (USOD) on the drying process and quality characteristics of lotus root using penetrating microwave hot air fluidized bed drying (PMHAD). The results indicate that USOD pretreatment (55 °C, 30 min) reduced the moisture content of lotus root by 18.4 %, with PPO and POD activities reduced to 34.7 % and 62.9 %, respectively. Compared to the unpretreated group, this pretreatment preserved the cell compactness of lotus root, thereby preventing the loss of phenolic compounds (increased by 9.1 %) and antioxidant activity (increased by 13.9 %). Morphological analysis of cell structure further revealed that changes in TPA parameters, shrinkage rate, and rehydration rate were closely associated with cell structure compactness. For samples subjected to USOD pretreatment, increasing microwave power during PMHAD induced microstructural changes in the cells. At a microwave power of 1.5 W/g, the maximum cell equivalent diameter reached 54.12 μm, while cell compactness decreased to 0.855, and relative crystallinity dropped to 16.86, leading to the loss of intracellular and thermosensitive substances. Principal component analysis highlighted the extent of damage and trend changes observed during the lotus root drying process.