Search

American lotus (Nelumbo lutea) is one of the two species in Nelumbo and has only yellow flower. Identification of total flavonoids showed wild American lotus contained almost only flavonols with quercetin 3-O-glucuronide to be the dominant pigment. The variation tendency of the total flavonol content was coincident with yellow color variation of petals during flower development. To understand the mechanism of accumulation and constituent of pigments in petals, three pivotal genes, NlFLS1, NlFLS2 and NlFLS3, which were predicted to encode flavonol synthases were isolated and characterized by analyses of basic bioinformatics, temporal and spatial expression patterns and enzymatic activity. Their temporal expression levels showed the same variation tendency, which was also consistent with the development-dependent variation of total flavonol content. Spatial expression patterns indicated the three genes should function in petals. All the three proteins were demonstrated to be bifunctional dioxygenase, possessing both flavonol synthase activity and flavanone 3-hydroxylase activity. Besides, other flavonol biosynthesis related genes were also investigated on their expression levels to give more clues on the mechanism. Substrate preferences of the three FLSs, substrate competitions between the FLSs and other flavonol biosynthesis related enzymes, and the greatly differential expression levels between F3’H (flavonoid 3′-hydroxylase) and F3’5’H (flavonoid 3′,5′-hydroxylase) contributed to the flavonol constituent in the petals of America lotus, namely abundant quercetin-derivatives while very few kaempferol-derivatives and myricetin-derivatives.

Tropical lotus (Nelumbo) is an important and unique ecological type of lotus germplasm. Understanding the genetic relationship and diversity of the tropical lotus is necessary for its sustainable conservation and utilization. Using 42 EST-SSR (expressed sequence tag-simple sequence repeats) and 30 SRAP (sequence-related amplified polymorphism) markers, we assessed the genetic diversity and inferred the ancestry of representative tropical lotus from Thailand and Vietnam. In total, 164 and 41 polymorphic bands were detected in 69 accessions by 36 EST-SSR and seven SRAP makers, respectively. Higher genetic diversity was revealed in Thai lotus than in Vietnamese lotus. A Neighbor-Joining tree of five main clusters was constructed using combined EST-SSR and SRAP markers. Cluster I included 17 accessions of Thai lotus; cluster II contained three Thai accessions and 11 accessions from southern Vietnam; and cluster III was constituted by 13 accessions of seed lotus. Consistent with the results from the Neighbor-Joining tree, the genetic structure analysis showed that the genetic background of most Thai and Vietnamese lotus was pure, as artificial breeding has been rare in both countries. Furthermore, these analyses indicate that Thai and Vietnamese lotus germplasms belong to two different gene pools or populations. Most lotus accessions are genetically related to geographical distribution patterns in Thailand or Vietnam. Our findings showed that the origin or genetic relationships of some unidentified lotus sources can be evaluated by comparing morphological characteristics and the data of molecular markers. In addition, these findings provide reliable information for the targeted conservation of tropical lotus and parent selection in breeding novel cultivars of lotus.

Abstract Background Lotus (Nelumbo Adans.) is used as an herbal medicine and the flowers are a source of natural flavonoids. ‘Da Sajin’, which was firstly found in the plateau area, is a natural mutant in flower color with red streamers dyeing around white petals. Results The LC–MS-MS results showed that eight anthocyanin compounds, including cyanidin 3-O-glucoside, cyanidin 3-O-galactoside, malvidin 3-O-galactoside, and malvidin 3-O-glucoside, were differentially enriched in red-pigmented tissues of the petals, whereas most of these metabolites were undetected in white tissues of the petals. Transcriptome profiling indicated that the relative high expression levels of structural genes, such as NnPAL, NnF3H, and NnANS, was inconsistent with the low anthocyanin concentration in white tissues. Members of the NnMYB and NnbHLH transcription factor families were presumed to play a role in the metabolic flux in the anthocyanin and proanthocyanidin biosynthetic pathway. The expression model of translational initiation factor, ribosomal proteins and SKP1–CUL1–F-box protein complex related genes suggested an important role for translational and post-translational network in anthocyanin biosynthesis. In addition, pathway analysis indicated that light reaction or photo destruction might be an important external cause for floral color determination in lotus. Conclusions In this study, it is supposed that the natural lotus mutant ‘Da Sajin’ may have originated from a red-flowered ancestor. Partial loss of anthocyanin pigments in petals may result from metabolic disorder caused by light destruction. This disorder is mainly regulated at post translation and translation level, resulting in a non-inherited phenotype. These results contribute to an improved understanding of anthocyanin metabolism in lotus, and indicate that the translational and post-translational regulatory network determines the metabolic flux of anthocyanins and proanthocyanidins under specific environmental conditions.

Late embryogenesis abundant (LEA) proteins are extremely hydrophilic proteins imperatively associated with plant growth and development, as well as cell protection from abiotic stress. However, the genome-wide characterization of LEA gene family remains limited, especially in aquatic species such as lotus (Nelumbo spp.). Here, 57 putative LEA genes, including 28 NnLEAs and 29 NlLEAs were identified in the N.nucifera and N.lutea genomes, respectively. A total of 27 homologous LEA gene pairs were identified, indicating high degree of sequence homologies between the two Nelumbo species. Secondary structure prediction indicated high prevalence of alpha (α) helix structure among LEA proteins in the LEA_1, LEA_4, and SMP groups. Screening of putative promoter cis -elements revealed that NnLEA genes were involved in diverse biological processes. Most NnLEA genes were predominantly expressed in the late cotyledons and plumules development stages, suggesting their potential vital roles in lotus seed maturation. In addition, genes co-expressed with NnLEAs were involved in ABA signaling, seed maturation, and development processes. Overall, this study provides new insights for the in-depth understanding of the functions of NnLEA proteins in lotus seed development, and could act as a useful reference for the molecular breeding of seeds with prolonged lifespan. [ABSTRACT FROM AUTHOR]

Background: Lotus (Nelumbo Adans.) is used as an herbal medicine and the flowers are a source of natural flavonoids. 'Da Sajin', which was firstly found in the plateau area, is a natural mutant in flower color with red streamers dyeing around white petals. Results: The LC–MS-MS results showed that eight anthocyanin compounds, including cyanidin 3-O-glucoside, cyanidin 3-O-galactoside, malvidin 3-O-galactoside, and malvidin 3-O-glucoside, were differentially enriched in red-pigmented tissues of the petals, whereas most of these metabolites were undetected in white tissues of the petals. Transcriptome profiling indicated that the relative high expression levels of structural genes, such as NnPAL, NnF3H, and NnANS, was inconsistent with the low anthocyanin concentration in white tissues. Members of the NnMYB and NnbHLH transcription factor families were presumed to play a role in the metabolic flux in the anthocyanin and proanthocyanidin biosynthetic pathway. The expression model of translational initiation factor, ribosomal proteins and SKP1–CUL1–F-box protein complex related genes suggested an important role for translational and post-translational network in anthocyanin biosynthesis. In addition, pathway analysis indicated that light reaction or photo destruction might be an important external cause for floral color determination in lotus. Conclusions: In this study, it is supposed that the natural lotus mutant 'Da Sajin' may have originated from a red-flowered ancestor. Partial loss of anthocyanin pigments in petals may result from metabolic disorder caused by light destruction. This disorder is mainly regulated at post translation and translation level, resulting in a non-inherited phenotype. These results contribute to an improved understanding of anthocyanin metabolism in lotus, and indicate that the translational and post-translational regulatory network determines the metabolic flux of anthocyanins and proanthocyanidins under specific environmental conditions. [ABSTRACT FROM AUTHOR]

SUMMARY: Both gene duplication and alternative splicing (AS) drive the functional diversity of gene products in plants, yet the relative contributions of the two key mechanisms to the evolution of gene function are largely unclear. Here, we studied AS in two closely related lotus plants, Nelumbo lutea and Nelumbo nucifera, and the outgroup Arabidopsis thaliana, for both single‐copy and duplicated genes. We show that most splicing events evolved rapidly between orthologs and that the origin of lineage‐specific splice variants or isoforms contributed to gene functional changes during species divergence within Nelumbo. Single‐copy genes contain more isoforms, have more AS events conserved across species, and show more complex tissue‐dependent expression patterns than their duplicated counterparts. This suggests that expression divergence through isoforms is a mechanism to extend the expression breadth of genes with low copy numbers. As compared to isoforms of local, small‐scale duplicates, isoforms of whole‐genome duplicates are less conserved and display a less conserved tissue bias, pointing towards their contribution to subfunctionalization. Through comparative analysis of isoform expression networks, we identified orthologous genes of which the expression of at least some of their isoforms displays a conserved tissue bias across species, indicating a strong selection pressure for maintaining a stable expression pattern of these isoforms. Overall, our study shows that both AS and gene duplication contributed to the diversity of gene function during the evolution of lotus. Significance Statement: We explain the relative contributions of gene duplication and alternative splicing (AS) to the evolution of gene functionality during lotus (Nelumbo spp.) species divergence. Our study highlights the rapid evolution of AS events and the contribution of lineage‐specific isoforms to gene functional changes during species divergence and elucidates the relationships between AS and gene duplication in plants by highlighting their interplay in creating gene functional diversity. [ABSTRACT FROM AUTHOR]

Simple Summary: The new species of Nelumbo reported in this paper is the first fossil record of lotus in Northwest China thus far, which can provide valuable information regarding the late Middle Miocene biocoenosis composition and the paleoenvironment of the Qaidam Basin on the northern Tibetan Plateau. The Neogene environment and paleovegetation of today's semi-arid and arid Central Asia remain elusive. Little is known about the effect of paleoclimatic change on the distribution and ecological response mechanisms of aquatic plants, especially on the Tibetan Plateau. Here, we report a new species of Nelumbo Adanson, including leaves, receptacles, and fruits, namely Nelumbo delinghaensis sp. nov., from the Upper Youshashan Formation of the upper Middle Miocene in the northern Qaidam Basin on the Tibetan Plateau. The new species comprises centrally peltate leaves with 12–15 actinodromous primary veins and a receptacle embedded with ca. 15–30 fruits, with an unlobed central disc. Megafossils of lotus from northwest China broaden the geographical and stratigraphic ranges of Nelumbo. Our findings suggest that a large freshwater lake body surrounded by temperate forests and grassland developed in the Qaidam Basin during the late Middle Miocene, in sharp contrast to the present desert vegetation. The climate used to be sufficiently warm and moist enough to support a forest-steppe ecosystem with abundant freshwater bodies. [ABSTRACT FROM AUTHOR]

• Phylogenetic and evolutionary analysis of SWEET genes in 13 plant species. • Systematic identification and functional characterization of SWEET genes in lotus. • Lotus SWEET proteins were localized in the plasma membrane. • Transcriptional regulation and co-expression network analysis of NnSWEET genes. • NnSWEET14 positively regulates soluble sugar accumulation in lotus seeds. The Sugars Will Eventually be Exported Transporter (SWEET) proteins are a group of sugar transporters that are present in various organisms and facilitate the flux of sugars across cell membranes. In this study, we identified SWEET proteins from 13 representative plant species and further classified them phylogenetically into four clades. Different rates of contraction and expansion of SWEET genes were observed among different species. Our focus was on the characteristics and biological functions of SWEET genes in the basal eudicot lotus. A total of 26 SWEET genes were identified in Nelumbo , including 14 NnSWEETs in N. nucifera and 12 NlSWEETs in N. lutea. The expansion of SWEET genes in Nelumbo was driven by tandem and segmental duplication events. Analysis of three-dimensional (3D) structures revealed that SWEET proteins typically consist of two 3-TM units (THB1 and THB2) and are attached via the center TM4. Subcellular localization assays demonstrated that the NnSWEET proteins were localized in the plasma membrane. The potential transcriptional regulation mechanisms were investigated by systematically scanning for binding transcription factor in the promoter regions of NnSWEET genes. Some NnSWEETs were found to be preferentially expressed during lotus seed development, and co-expression analysis revealed that certain NnSWEET genes were involved in sugar and starch metabolism. Moreover, transient overexpression of NnSWEET14 significantly increased the soluble sugar content in lotus seed. These findings not only lay the groundwork for functional characterization of SWEET genes in Nelumbo , but also provide valuable genetic resources for future improvement of lotus seed quality. [ABSTRACT FROM AUTHOR]

The Neogene environment and paleovegetation of today’s semi-arid and arid Central Asia remain elusive. Little is known about the effect of paleoclimatic change on the distribution and ecological response mechanisms of aquatic plants, especially on the Tibetan Plateau. Here, we report a new species of Nelumbo Adanson, including leaves, receptacles, and fruits, namely Nelumbo delinghaensis sp. nov., from the Upper Youshashan Formation of the upper Middle Miocene in the northern Qaidam Basin on the Tibetan Plateau. The new species comprises centrally peltate leaves with 12–15 actinodromous primary veins and a receptacle embedded with ca. 15–30 fruits, with an unlobed central disc. Megafossils of lotus from northwest China broaden the geographical and stratigraphic ranges of Nelumbo. Our findings suggest that a large freshwater lake body surrounded by temperate forests and grassland developed in the Qaidam Basin during the late Middle Miocene, in sharp contrast to the present desert vegetation. The climate used to be sufficiently warm and moist enough to support a forest-steppe ecosystem with abundant freshwater bodies.

Living specimens of three colour forms (pink, white and yellowish white) of Nelumbo nucifera Gaertn. were observed in different natural habitats of Bangladesh and collected. Fresh specimens were studied in the field as well as in the laboratory. After detailed study it was concluded that the three colour forms available in Bangladesh belong to the same species, Nelumbo nucifera Gaertn. However, the yellowish white colour form, having many stamens petaloid, is considered as a new cultivar Nelumbo nucifera 'Gomoti' and reported here as the first lotus cultivar from Bangladesh. [ABSTRACT FROM AUTHOR]

Compared with rose, chrysanthemum, and water lily, the absence of short-wide and long-narrow tepals of ornamental lotus (Nelumbo Adans.) limits the commercial value of flowers. In this study, the genomes of two groups of lotus mutants with wide-short and narrow-long tepals were resequenced to uncover the genomic variation and candidate genes associated with tepal shape. In group NL (short for N. lutea, containing two mutants and one control of N. lutea), 716,656 single nucleotide polymorphisms (SNPs) and 221,688 insertion-deletion mutations (Indels) were obtained, while 639,953 SNPs and 134,6118 Indels were obtained in group WSH (short for ‘Weishan Hong’, containing one mutant and two controls of N. nucifera ‘Weishan Hong’). Only a small proportion of these SNPs and Indels was mapped to exonic regions of genome: 1.92% and 0.47%, respectively, in the NL group, and 1.66% and 0.48%, respectively, in the WSH group. Gene Ontology (GO) analysis showed that out of 4890 (NL group) and 1272 (WSH group) annotated variant genes, 125 and 62 genes were enriched (Q < 0.05), respectively. Additionally, in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, 104 genes (NL group) and 35 genes (WSH group) were selected (p < 0.05). Finally, there were 306 candidate genes that were sieved to determine the development of tepal shape in lotus plants. It will be an essential reference for future identification of tepal-shaped control genes in lotus plants. This is the first comprehensive report of genomic variation controlling tepal shape in lotus, and the mutants in this study are promising materials for breeding novel lotus cultivars with special tepals.

Muscle atrophy refers to a decline in muscle mass and function, which has become a global concern due to the aging population. Various clinical trials have investigated the inhibitors of myostatin (MSTN). They have shown promising improvements in muscle function and quality of life. However, there are no drugs specifically targeting MSTN that have been approved for clinical use. In this study, we virtually screened liensinine (LIE), a food ( Nelumbo nucifera )-derived compound, with low toxicity, from over 1.1 million compounds. We subsequently identified it as a potential candidate that targets MSTN by a cellular thermal shift assay (CETSA) and drug affinity response target stability (DARTS) assay. Further validation through cellular and in vivo studies demonstrated its promising potential in combating muscle atrophy. The mechanism of action may involve hindering the interaction between MSTN and the activin receptor type IIB (ActRIIB) and downregulating the expression of downstream proteins, including the muscle RING-finger protein-1 (MuRF-1) and muscle atrophy F-box (MAFbx)/Atrogin-1, ultimately promoting muscle regeneration. These results provide a strong foundation for future studies to explore the therapeutic potential of LIE in clinical settings.

The seeds of lotus ( Nelumbo nucifera Gaertn.) have been used as significant medicinal and nutritional ingredients worldwide. The abundant proteins and polysaccharides in lotus seeds make them susceptible to contamination by aflatoxin (AF), a fungal toxic metabolite. This study was conducted to investigate the susceptibility of lotus seeds at different stages of ripening to AF contamination, as well as the mechanism of the contamination. Seven groups of lotus receptacles with seeds at different ripening stages (A-G, from immature to mature) were used for the experiment. Spores of Aspergillus flavus , an AF producer, were inoculated on the water-gap area of the seeds in each receptacle. Then, each receptacle was covered with a sterilized bag, and its stalk part was soaked in water containing a life-prolonging agent, after which it was kept at room temperature for 14 days. The AF content of each whole inoculated seed from the A-G groups and that of each seed part (pericarp, cotyledon, and embryo) from the D and E groups were determined using high-performance liquid chromatography. Microtome sections were prepared from the samples and observed under a light microscope and scanning electron microscope. The seeds from the A and D groups had higher AF contents than the seeds from the B, C, E, F, and G groups, indicating that the condition of the water-gap area and the development of the embryo and cotyledon parts of the seeds are associated with AF contamination.

Bacterial infection is considered one of the major issues in fish culturing that results in economic losses. Metal nanoparticles are a cutting-edge and effective disease management and preventive strategy because of their antibacterial ability. In this investigation, the selenium nanoparticles were prepared by a biological method using Nelumbo nucifera leaves extract. The in-vitro antibacterial activity of N. nucifera synthesized selenium nanoparticles (NN-SeNPs) was tested against Aeromonas veronii. A treatment assay was conducted on 210 Oreochromis niloticus (average body weight: 27 ± 2.00 g). A preliminary approach was conducted on 90 fish for determination of the therapeutic concentration of NN-SeNPs which was found to be 4 mg/L. Fish (n = 120) were categorized into four groups for 10 days; G 1 (control) and G 2 (NN-SeNPs) were non-challenged and treated with 0 and 4 mg/L NN-SeNPs, respectively. While, G 3 and G 4 were infected with 2 × 10 6  CFU/mL of A. veronii and treated with 0 and 4 mg/L NN-SeNPs, respectively. NN-SeNPs exhibited an inhibition zone against A. veronii with a diameter of 16 ± 1.25 mm. The A. veronii infection increased the hepato-renal biomarkers (alanine and aspartate aminotransferases and creatinine) than the control group. An oxidative stress was the consequence of A. veronii infection (higher malondialdehyde and hydrogen peroxide levels with lower glutathione peroxidase superoxide, dismutase, and catalase activity). A. veronii infection resulted in lower immunological biomarker values (immunoglobulin M, lysozyme, and complement 3) with higher expression of the inflammatory cytokines (interleukin-1β and tumor necrosis factor-ɑ) as well as lower expression of the anti-inflammatory cytokines (interleukin-10 and transforming growth factor-β). Therapeutic application with 4 mg/L NN-SeNPs prevented the disease progression; and modulated the hepato-renal function disruptions, oxidant-immune dysfunction, as well as the pro/anti-inflammatory cytokines pathway in the A. veronii-infected fish. These findings suggest that NN-SeNPs, employed as a water therapy, can safeguard fish from the harmful effects of A. veronii and serve as a promising antibacterial agent for sustainable aquaculture., Competing Interests: Declaration of competing interest The authors claim that there is no any conflict of interest., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Graphical abstract The fabricated lotus leaf with light absorption and heat localization was proposed to as solar thermal conversion devices for solar water evaporation. Highlights • A novel and inexpensive biological material-the lotus leaf is used for solar water evaporation device. • The fabricated lotus leaf has excellent properties of light absorption, heat localization, water supply and vapor escape. • The water evaporation capacity of the fabricated lotus leaf is greatly improved, reaches at 3.10 kg/(m2h). Abstract Recently, a variety of artificial structures have been designed and fabricated to improve energy conversion efficiency. Lotus leaf, a kind of living organism, is famous for its hydrophobic structure on the surface, but here it's used for solar thermal conversion by changing its surface structure. SEM, XRD, HRTEM, FLIR, Raman and BET results demonstrated that carbonized lotus leaf became hydrophilic. In the evaporation process under a lamp illumination, the mass changed as high as 3.10 kg/(m2h), and the temperature increased to 60.1 °C. These findings not only reveal the potential to treat lotus leaf as a low-cost material for solar water evaporation, but also provide inspiration for the future development of high-performance solar thermal conversion devices. [ABSTRACT FROM AUTHOR]

Highlights • The antioxidant and anti-inflammatory mechanisms of flavonoids in lotus plumule were systematically analyzed using radical scavenging assays and ELISA kits. • The affinity UF-LC/MS was employed to rapidly screen and identify 12 bioactive flavonoids showing specific binding to COX-2 in lotus plumule. • Flavonoids O -glycosides displayed comparable binding affinities to COX-2 compared with flavonoids C -glycosides. Abstract The antioxidant and anti-inflammatory mechanisms of action of flavonoids in lotus plumule were systematically analyzed using radical scavenging assays and ELISA kits. By this means, flavonoids displayed significant antioxidant activity by donating electron, H atom as well as capturing DPPH and ABTS+ free radicals, and anti-inflammatory effect by inhibiting the production of the inflammatory mediators (NO radicals, PGE 2 and TNF-α) and pro-inflammatory cytokines (IL-1β and IL-6). Meanwhile, the bioactive components against inflammation targeting COX-2 were also revealed using ultrafiltration coupled to LC-MS (UF-LC/MS). In this way, 12 components showing specific binding to COX-2 were screened out and identified. The structure-activity relationships suggested that flavonoids O -glycosides displayed comparable binding affinities to COX-2 compared with flavonoids C -glycosides and could be considered as the main active components. This study will provide valuable information for the further exploration of lotus plumule as functional foods or in pharmaceutical industries in the near future. [ABSTRACT FROM AUTHOR]

Nelumbo nucifera Gaertn., an aquatic medicinal plant (Nelumbonaceae family), has a history of use in traditional medicine across various regions. Our previous study demonstrated the skin anti-aging potential of its stamen ethanolic extract by effectively inhibiting collagenase and tyrosinase enzymes. While the major constituents of this extract are well documented, there is a lack of research on the individual compounds' abilities to inhibit skin aging enzymes. Therefore, this study aimed to evaluate the anti-aging potential of the primary flavonoids found in N. nucifera using both in silico and in vitro approaches. Our initial step involved molecular docking to identify compounds with the potential to inhibit collagenase, elastase, and tyrosinase. Among the seven flavonoids studied, kaempferol-3- O -robinobioside (Kae-3-Rob) emerged as the most promising candidate, exhibiting the highest docking scores for three skin aging-related enzymes. Subsequent enzyme-based inhibition assays confirmed that Kae-3-Rob displayed robust inhibitory activity against collagenase (58.24 ± 8.27%), elastase (26.29 ± 7.16%), and tyrosinase (69.84 ± 6.07%). Furthermore, we conducted extensive 200-ns molecular dynamics (MD) simulations, revealing the stability of the complexes formed between Kae-3-Rob and each enzyme along the MD simulation time. MM/PBSA-based binding free energy calculations indicated the considerably stronger binding affinity of Kae-3-Rob for collagenase and tyrosinase compared to elastase, which was related to the greater percentage of hydrogen bond occupations. These computational findings were consistent with the relatively high inhibitory activity of Kae-3-Rob against collagenase and tyrosinase observed in our in vitro experiment. In conclusion, the results obtained from this comprehensive study suggest that Kae-3-Rob, a key flavonoid from N. nucifera , holds significant potential as a source of bioactive compounds for anti-aging cosmeceutical and other phytopharmaceutical application.

Abstract Nuciferine, a bioactive component extracted from the lotus leaf , has been reported to have various anti-inflammatory effects. In the present study, we aimed to investigate the anti-inflammatory effects and mechanism of nuciferine on lipopolysaccharide (LPS)-stimulated BV2 microglia cells. The anti-inflammatory activity of nuciferine was measured by ELISA to detect the inflammatory mrdiators secretion in LPS-simulated BV2 microglia cells. The results demonstrated that nuciferine significantly inhibited LPS-induced TNF-α, IL-1β, PGE 2 and NO secretion. LPS-induced NF-κB activation was also suppressed by nuciferine. Further studies showed that nuciferine increased the expression of PPAR-γ. Functional aspects were analyzed using PPAR-γ specific inhibitor GW9662, which attenuated the LPS-induced secretion of proinflammatory mediators, such as TNF-α, IL-1β, PGE 2 , and NO. In conclusion, these results suggested that nuciferine activated PPAR-γ, which subsequently inhibited LPS-induced inflammation in BV2 cells. Highlights • Nuciferine significantly inhibited LPS-induced TNF-α, IL-1β, PGE 2 and NO production. LPS-induced NF-κB activation was suppressed by nuciferine. • Nuciferine increased the expression of PPAR-γ. • PPAR-γ specific inhibitor GW9662 attenuated the LPS-induced TNF-α, IL-1β, PGE 2 , and NO production. [ABSTRACT FROM AUTHOR]

Natural products are gaining much momentum worldwide because they have a broad spectrum of biological effects and present excellent opportunities for bioproducts development. With this fact, this study has been designed to investigate for the first time the effects of the ethyl acetate (EA), methanolic (MeOH), and water (W) extracts of Lotus aegaeus (La) and Iberis sempervirens (Is) on key enzymes as well as to quantify antioxidant capacities. The total phenolic and flavonoid content were determined using colorimetric methods and the individual phenolic compounds were assessed by LC–MS/MS analysis. Quercetin hexoside was the dominant compound in L. aegaeus , particularly in methanol extract, while the ethyl acetate and methanol extracts of I. sempervirens were characterized by the presence scopoletin and hinic acid. The antioxidant abilities of the investigated extracts were tested using different assays including free radical scavenging, reducing power, phosphomolybdenum, and metal chelating. All the extracts showed strong antioxidant abilities. For both species, the ethyl acetate extracts were more potent against cholinesterases and α-amylase, while the methanol extracts were most active against α-glucosidase. Only the water extract, followed by methanol of I. sempervirens exhibited notable inhibitory activity against tyrosinase. In addition, the dominant compounds were docked against tyrosinase and α-glucosidase to investigate their predicted binding affinity and interactions with the active site. In conclusion, L. aegaeus and I. sempervirens showed potent biological attributes, which advocates for further studies to explore their potential use as phytopharmaceuticals. [ABSTRACT FROM AUTHOR]

Background: Flower morphology, a phenomenon regulated by a complex network, is one of the vital ornamental features in Nelumbo nucifera. Stamen petaloid is very prevalent in lotus flowers. However, the mechanism underlying this phenomenon is still obscure. Results: Here, the comparative transcriptomic analysis was performed among petal, stamen petaloid and stamen through RNA-seq. Using pairwise comparison analysis, a large number of genes involved in hormonal signal transduction pathways and transcription factors, especially the MADS-box genes, were identified as candidate genes for stamen petaloid in lotus. Conclusions: Taken together, these results provide an insight into the molecular networks underlying lotus floral organ development and stamen petaloid. [ABSTRACT FROM AUTHOR]

Lotus effect is the superhydrophobicity property, and widely used for self-cleaning in modern textile engineering. This paper reveals that the lotus effect is a kind of nanoeffect or size effect in nanotechnology, the surface morphology, solution's molecule weight, and temperature are three main factors affecting the lotus effect. Solutions' pH values or ionic liquids are also discussed in this paper. A series of experiments are carried out to measure contact angles for different solutions/ liquids on the lotus surface at different temperature. [ABSTRACT FROM AUTHOR]

Genetic and genotypic variabilities of a rare relict aquatic plant Nelumbo komarovii Grossh. from six natural populations of Primorsky krai (Russia) were assessed using isozyme analysis. The highest genetic and genotypic diversities were observed in the Razdol’noe and Okeanskaya populations, which can be explained by cross-pollination participation in the seed formation for maintenance of the Razdol’noe population size and by sowing seeds from different habitats for the Okeanskaya population. Low polymorphism at the population level (P = 8.97, HO = 0.055, HE = 0.039) is determined by the history of existence of the species from the Tertiary Period as well as by the influence of gene drift. Clonal renewal plays a decisive role in the propagation of N. komarovii in most natural populations. [ABSTRACT FROM AUTHOR]

Taro, Colocasia esculenta (L.) Schott, is a vegetable and starchy root crop cultivated in Asia, Oceania, the Americas, Africa, and the Mediterranean. Very little is known about its early history in the Mediterranean, which previous authors have sought to trace through Classical (Greek and Latin) texts that record the name colocasia (including cognates) from the 3rd century BC onwards. In ancient literature, however, this name also refers to the sacred lotus, Nelumbo nucifera Gaertn. and its edible rhizome. Like taro, lotus is an alien introduction to the Mediterranean, and there has been considerable confusion regarding the true identity of plants referred to as colocasia in ancient literature. Another early name used to indicate taro was arum, a name already attested from the 4th century BC. Today, this name refers to Arum, an aroid genus native to West Asia, Europe, and the Mediterranean. Our aim is to explore historical references to taro in order to clarify when and through which routes this plant reached the Mediterranean. To investigate Greek and Latin texts, we performed a search using the Thesaurus Linguae Graecae (TLG) and the Thesaurus Linguae Latinae (TLL), plus commentaries and English and French translations of original texts. Results show that while in the early Greek and Latin literature the name kolokasia (Greek κολοκάσια) and its Latin equivalent colocasia refer to Nelumbo nucifera Gaertn., after the 4th century AD a poorly understood linguistic shift occurs, and colocasia becomes the name for taro. We also found that aron (Greek ἄρον) and its Latin equivalent arum are names used to indicate taro from the 3rd century BC and possibly earlier. [ABSTRACT FROM AUTHOR]

Fossil leaves of Nelumbo jiayinensis sp. nov. are described from the Yong'ancun Formation (Santonian) in Jiayin, Heilongjiang, Northeast China. This is the first report on fossil Nelumbo from the Upper Cretaceous of China. The leaves are simple with entire margins, orbicular or sub-orbicular in shape, with a peltate and symmetric lamina. The venation is actinodromous with 20–25 primary veins, the secondary and tertiary veins are poorly developed and interweave into meshes. The areoles are irregularly polygonal in shape and well developed both in upper and lower surfaces. Combined with data derived from associated fossil mega-plants, spores and pollen, bivalves and dinosaur footprints, the aquatic angiosperm Nelumbo existed in a fluviolacustrine environment under a warm but seasonal temperate climate. [ABSTRACT FROM AUTHOR]

Sacred lotus is a basal eudicot plant that has been cultivated in Asia for over 7,000 years for its agricultural, ornamental, religious, and medicinal importance. A notable characteristic of lotus is the seed longevity. Extensive endeavors have been devoted to dissect its genome assembly, including the variety China Antique, which germinated from a 1,300-year-old seed. Here, cytogenetic markers representing the 10 largest megascaffolds, which constitute approximately 70% of the lotus genome assembly, were developed. These 10 megascaffolds were then anchored to the corresponding lotus chromosomes by fluorescence in situ hybridization using these cytogenetic markers, and a set of chromosome-specific cytogenetic markers that could unambiguously identify each of the 8 chromosomes was generated. Karyotyping was conducted, and a nomenclature based on chromosomal length was established for the 8 chromosomes of China Antique. Comparative karyotyping revealed relatively conserved chromosomal structures between China Antique and 3 modern cultivars. Interestingly, significant variations in the copy number of 45S rDNA were detected between China Antique and modern cultivars. Our results provide a comprehensive view on the chromosomal structure of sacred lotus and will facilitate further studies and the genome assembly of lotus. [ABSTRACT FROM AUTHOR]

A new salting-out extraction method, namely chelatometric salting-out extraction, was established for rapidly extracting flavonoids fromFolium nelumbinis. Borax was used as a chelating agent and an ethanol/K2HPO4system as the salting-out extraction system. The maximum flavonoid concentration in the top phase was observed at an ethanol concentration of 43.0% and an amount of salt of 2.45 g under the experimental conditions. The pH value of the system and extraction time had no obvious influence on the extraction efficiency of flavonoids. The results also showed that the extraction efficiency of flavonoids exceeds 90.4% at the first time extraction. Moreover, the antioxidant activities of flavonoids were evaluated by DPPH▪ radical assays. [ABSTRACT FROM PUBLISHER]

Abstract: Nelumbo nucifera Gaertn., also known as the sacred lotus, is extensively cultivated in Southeast Asia, primarily for food and as an herbal medicine. This article reviews studies published between 1995 and 2017, on flavonoid and phenolic acid profiles and contents of 154 different cultivars of lotus. So far, some 12 phenolic acids and 89 to 90 flavonoids (47 flavonols, 25 to 26 flavons, 8 flavan‐3‐ols, 4 flavanons, and 5 anthocyanins) have been isolated from different parts of the lotus plant, including its leaves (whole leaf, leaf pulp, leaf vein, and leaf stalk), seeds (seedpod, epicarp, coat, kernel, and embryo), and flowers (stamen, petal, pistil, and stalk), although not all of them have been quantified. Factors affecting flavonoids and phenolic acid profiles, including types of tissues and extracting factors, are discussed in this review, in order to maximize the application of the lotus and its polyphenols in the food industry. Health promotion activities, attributed to the presence of flavonoids and phenolic acids, are described along with toxicology studies, illustrating appropriate usage and safe consumption dosages of lotus extracts. This review also presents the controversies and discusses the research gaps that limit our ability to obtain a thorough understanding of the bioactivities of lotus extracts. [ABSTRACT FROM AUTHOR]

In order to find out the key factors to affect the texture variation and the formation mechanism of different cultivars lotus rhizomes after thermal processing, representative lotus rhizomes harvested in year round with 2 months interval, including Lulinhu, Miancheng, and Elian 5, were chosen to calculate the cause of thermal process texture. The texture (hardness), content of different fractions of alcohol insoluble residue (AIR), and microstructure of the cell wall components of the lotus rhizomes exhibited changes during processing. The changes of three pectin fractions in the three lotus rhizomes cultivars were compared by combining the effect of thermal treatment on the lotus rhizome AIR pectin content degree of esterification (DE) and analysing the texture and microstructure, the cell wall materials were found to be the crucial factor in this process. Another six cultivars lotus rhizomes have been employed to replicate the above mentioned results, the total data were used to calculate the chelator soluble fraction (CSF) to water soluble fraction (WSF) ratio value (0.25), which determines the texture of the lotus rhizomes after thermal-processing. The CSF/WSF ratio values (0.25) will give an index for the lotus rhizome processing food industry. [ABSTRACT FROM AUTHOR]

The effects of lotus root amylopectin (LRA) on the formation of whey protein isolate (WPI) gels were investigated at the concentration range from 0 to 1.0% (w/v) by determining the texteral, thermal and rheological properties. Results exhibited these properties of WPI gels could be significantly enhanced by the addition of LRA in a concentration-dependent manner. Compared the gel with free of starch, the gel strength, water holding capacity and thermal transition temperature of WPI gel containing 1% (w/v) amylopectin were enhanced by 12.7-fold, 24.9% and 3.6 °C, respectively. According to the analysis of scanning electron microscopy, colorimetric reaction and Fourier transform infrared spectroscopy measurements, it was concluded that the LRA-induced enhancement of WPI gel properties was possibly attributed to the formation of stable three-dimensional gel network, increased contents of reactive sulfhydryl group, C N bond and/or N H bond. Results suggested that LRA might be a good gel modifier. [ABSTRACT FROM AUTHOR]

Lotus ( Neumbo nucifera , Gaertn) is the most important aquatic vegetable in China, with a cultivation history of over 3000 years. The emergy, energy, material, and money flows of three lotus root cultivation modes in Wanqingsha, Nansha District, Guangzhou, China were examined using Energy Systems Language models and emergy evaluation to better understand their ecological and economic characteristics on multiple spatial and temporal scales. The natural resource foundations, economic characteristics and sustainability of these modes were evaluated and compared. The results showed that although all three modes were highly dependent on purchased emergy inputs, their potential impacts as measured by the local (ELR L ) and global (ELR W ) environmental loading ratios were less than 1.2 and 0.7, respectively. The lotus-fish mode was the most sustainable with its emergy index of sustainable development (EISD) 2.09 and 2.13 times that of the pure lotus and lotus-shrimp modes, respectively. All three lotus-root production modes had superior economic viability, since their Output/Input ratio ranged from 2.56 to 4.95. The results indicated that agricultural systems may have different environmental impacts and sustainability characteristics at different spatial and temporal scales, and that these impacts and characteristics can be simultaneously explored using integrated emergy and economic evaluations. [ABSTRACT FROM AUTHOR]

To investigate the effect of 6-benzylaminopurine (6-BA) treatment on starch-sucrose metabolism in postharvest lotus seeds, the lotus pods were immersed with 20 mg L −1 6-BA and stored at 25 ± 1 °C for 8 days. Our results revealed that 6-BA treatment not only delayed the browning of lotus pods and seeds, but also inhibited the respiration rate of lotus pods. Compared with controls, 6-BA treatment enhanced the deposition of starch, which was supported by the decreased amylase level. Contrary to the alteration of starch content, glucose and fructose contents in lotus seeds were reduced by 6-BA treatment through inhibiting the production of hexose from sucrose and starch degradations. However, the sucrose content in 6-BA treated group was higher than that in control groups until 6th day of storage, which was resulted from enhanced sucrose phosphate synthase (SPS) level and inhibited activities of synthase-cleavage (SS-cleavage) and invertase by 6-BA treatment. These results indicated that 6-BA treatment could maintain the starch and sucrose contents of lotus seeds by affecting related-synthetic or degrading enzymes involved in starch-sucrose metabolism, and alleviate postharvest senescence of lotus pods and seeds. [ABSTRACT FROM AUTHOR]

Dehydrins (DHNs) play imperative role in the stress tolerance of high plants. In this study, the YSK2-type DHN (NnDHN1) and SK3-type DHN (NnDHN2) were investigated. The putative NnDHN1 and NnDNH2 shared conserved S-segment as well as K-segment, with distinct isoelectric points, kinase selectivities and number of functional motifs. Phylogenetic analysis revealed that NnDHNs were grouped with YnSKn- and SKn-type of DHNs in high plants. Additionally, NnDHN1 mRNA was only expressed in leaves and embryo. NnDHN2 mRNA was found in embryo, leaves, rhizome and leafstalk. NnDHNs mRNAs were not detected in root of N. nucifera. Real-time PCR assay demonstrated that the levels of NnDHN1 and NnDHN2 mRNAs were significantly elevated during cold temperature, while both were relatively stable in response to high temperature. Moreover, NnDHN2 mRNA was significantly increased after treatment with abscisic acid (ABA) or indole-3-acetic acid (IAA), while NnDHN1 mRNA was induced by ABA treatment with little change in response to IAA. These results illustrate two NnDHNs with partially overlapping function which exhibit different stress responsiveness. [ABSTRACT FROM AUTHOR]

Lotus pods were treated with 0.5 μL L −1 of 1-methylcyclopropene (1-MCP) and 3% lacquer wax and then stored at 25 ± 1 °C and 90%–95% relative humidity to investigate their effects alone and in combination on browning and postharvest quality during 8 d of shelf life. Respiration rate, firmness, reactive oxygen species (superoxide anion (O 2 −) production rate and H 2 O 2 concentration), malondialdehyde (MDA) and total phenol concentrations, and the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and polyphenol oxidase (PPO) were evaluated. 1-MCP or lacquer wax reduced browning and retained the quality of lotus pods and seeds. However, lacquer wax had little influence on the respiration rate, and 1-MCP-treated pods were firmer than untreated pods for only 6 d. The combination treatment of lacquer wax followed by 1-MCP treatment showed equivalent effects on respiration rate and firmness to lacquer wax alone. However, the lotus pods that were treated with 1-MCP first, and then coated with lacquer wax, had better retention of firmness and total phenol concentration, reduced respiration rate, O 2 − production rate, accumulation of H 2 O 2 and MDA, and browning degree, increased SOD and CAT activities, and decreased PPO and POD activities when compared with those in other treatments. Compared with controls, 1-MCP treatment followed by lacquer wax coating treatment also delayed cell wall degradation, plasmolysis, and preserved cellular integrity of lotus seeds. These results indicate combination treatment provided an effective method to delay the postharvest senescence of fresh lotus pods and seeds. [ABSTRACT FROM AUTHOR]

Free radicals generated from human body metabolisms or from environments are involved in development of degenerative diseases. Natural antioxidants could play an important role in prevention and cure of chronic diseases caused by free radicals. Sacred lotus or lotus (Nelumbo nucifera Gaertn.) is a widely used medicinal plant. Parts of lotus were used in Thai traditional medicine as cardio tonic and culinary. Different cultivars of lotuses are cultivated in Thailand. This study aimed to evaluate antioxidant activity and determine total phenolic contents from methanolic extract of leaf, stamen, outer petal, inner petal, stalk and seed pod of two cultivars of lotuses including white short flower (Sattabut) and pink short flower (Sattabongkoj) lotuses. The antioxidant activity by ABTS and DPPH methods ranged from 14.9±3.54 to 227.63±6.93 mgTEAC/gDW and 19.66±2.05 to 285.05±22.51 mgTEAC/gDW, respectively. Total phenolic contents were ranged from 8.80±1.17 to 109.90±4.37 mgGAE/gDW. The seed pod of the white short flower lotus (Sattabut) exhibited the highest antioxidant activity and total phenolic contents. This study provides basic information for development of natural antioxidants from the two lotus cultivars. [ABSTRACT FROM AUTHOR]

The predominant alkaloids in lotus leaves are aporphine alkaloids. These are the most important active components and have many pharmacological properties, but little is known about their biosynthesis. We used digital gene expression (DGE) technology to identify differentially-expressed genes (DEGs) between two lotus cultivars with different alkaloid contents at four leaf development stages. We also predicted potential genes involved in aporphine alkaloid biosynthesis by weighted gene co-expression network analysis (WGCNA). Approximately 335 billion nucleotides were generated; and 94% of which were aligned against the reference genome. Of 22 thousand expressed genes, 19,000 were differentially expressed between the two cultivars at the four stages. Gene Ontology (GO) enrichment analysis revealed that catalytic activity and oxidoreductase activity were enriched significantly in most pairwise comparisons. In Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, dozens of DEGs were assigned to the categories of biosynthesis of secondary metabolites, isoquinoline alkaloid biosynthesis, and flavonoid biosynthesis. The genes encoding norcoclaurine synthase (NCS), norcoclaurine 6-O-methyltransferase (6OMT), coclaurine N-methyltransferase (CNMT), N-methylcoclaurine 3'-hydroxylase (NMCH), and 3'-hydroxy-N-methylcoclaurine 4'-O-methyltransferase (4'OMT) in the common pathways of benzylisoquinoline alkaloid biosynthesis and the ones encoding corytuberine synthase (CTS) in aporphine alkaloid biosynthetic pathway, which have been characterized in other plants, were identified in lotus. These genes had positive effects on alkaloid content, albeit with phenotypic lag. The WGCNA of DEGs revealed that one network module was associated with the dynamic change of alkaloid content. Eleven genes encoding proteins with methyltransferase, oxidoreductase and CYP450 activities were identified. These were surmised to be genes involved in aporphine alkaloid biosynthesis. This transcriptomic database provides new directions for future studies on clarifying the aporphine alkaloid pathway. [ABSTRACT FROM AUTHOR]

Iron is an essential nutrient for legume-rhizobium symbiosis and accumulates abundantly in the nodules. However, the concentration of free iron in the cells is strictly controlled to avoid toxicity. It is known that ferritin accumulates in the cells as an iron storage protein. During nodule senescence, the expression of the ferritin gene, Ljfer1 , was induced in Lotus japonicus . We investigated a signal transduction pathway leading to the increase of Ljfer1 in the nodule. The Ljfer1 promoter of L. japonicus contains a conserved Iron-Dependent Regulatory Sequence (IDRS). The expression of Ljfer1 was induced by the application of iron or sodium nitroprusside, which is a nitric oxide (NO) donor. The application of iron to the nodule increased the level of NO. These data strongly suggest that iron-induced NO leads to increased expression of Ljfer1 during the senescence of L. japonicus nodules. [ABSTRACT FROM AUTHOR]

The purpose of this study is to prepare an oxyresveratrol (Oxy) microemulsion (ME) with improved Oxy’s solubility and stability and to investigate its antibrowning effects on fresh-cut lotus root slices. The formula of OxyME consisted of ethyl butyrate, Tween 80, PEG400, and water with w/w of 4%, 10.67%, 5.33%, and 80%, respectively. Encapsulating Oxy into OxyME greatly increased its solubility and stability compared with that of in water. Strong antibrowning effects were observed on fresh-cut lotus root slices treated with OxyME, even better than 4-hexylresorcinol. The addition of ascorbic acid (V C ) into OxyME greatly improved the Oxy stability in long-term storage and antibrowning effects on fresh-cut lotus root slices. However, the simultaneous addition of calcium chloride and V C did not obviously improve the antibrowning effects compared with the addition of V C alone. These results indicated that Oxy + V C ME may be suitable as an antibrowning agent for fresh-cut vegetables. [ABSTRACT FROM AUTHOR]

Mitogen-activated protein kinase (MAPK) cascade signaling pathway plays pivotal roles in various plant biological processes. However, systematic study of MAPK cascade gene families is yet to be conducted in lotus. Herein, 198 putative MAPK genes, including 152 MAP3Ks , 15 MKKs , and 31 MPKs genes were identified in Nelumbo. Segmental duplication was identified as the predominant factor driving MAPK cascade gene family expansion in lotus. MAPK cascade genes in N. nucifera and N. lutea shared high degree of sequence homologies, with 84, 9, and 19 homologous MAP3K, MKK, and MPK gene pairs being detected between the two species, respectively, with most genes predominantly undergoing purifying selection. Gene expression profiling indicated that NnMAPK cascade genes were extensively involved in plant development and submergence stress response. Co-expression analysis revealed potential interaction between transcription factors (TFs) and NnMAPK cascade genes in various biological processes. NnMKK showed predicted interactions with multiple NnMAP3K or NnMPK proteins, which suggested that functional diversity of MAPK cascade genes could be as a result of their complex protein interaction mechanisms. This first systematic analysis of MAPK cascade families in lotus provides deeper insights into their evolutionary dynamics and functional properties, which potentially could be crucial for lotus genetic improvement. [ABSTRACT FROM AUTHOR]

Background: The basic leucine zipper (bZIP) family is a predominant group of transcription factors in plants, involved in regulating plant growth, development, and response to stressors. Additionally, the bZIP gene family has a key role in anthocyanin production. Despite the significant role of bZIP genes in plants, their potential contribution in lotus remains understudied., Results: A total of 124 bZIP genes (59 NnbZIPs and 65 NlbZIPs) were identified from genomes of two lotus species. These genes were classified into 13 groups according to the grouping principle of the Arabidopsis bZIP gene family. Analysis of promoter cis-acting elements indicated that most bZIP gene family members in lotus are associated with response to abiotic stresses. The promoters of some bZIP genes contain MYB binding sites that regulate anthocyanin synthesis. We examined the anthocyanin content of the petals from three different colored lotus, combined with transcriptome data analysis and qRT-PCR results, showing that the expression trends of NnbZIP36 and the homologous gene NlbZIP38 were significantly correlated with the anthocyanin content in lotus petals. Furthermore, we found that overexpression of NnbZIP36 in Arabidopsis promoted anthocyanin accumulation by upregulating the expression of genes (4CL, CHI, CHS, F3H, F3'H, DFR, ANS and UF3GT) related to anthocyanin synthesis., Conclusions: Our study enhances the understanding of the bZIP gene family in lotus and provides evidence for the role of NnbZIP36 in regulating anthocyanin synthesis. This study also sets the stage for future investigations into the mechanism by which the bZIP gene family regulates anthocyanin biosynthesis in lotus., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Natural lotus seed oligosaccharides monomers (LOSs: LOS3-1, LOS3-2, and LOS4) were prepared by preparative chromatography and were hydroxyl-labeled with fluorescein isothiocyanate (FITC). The prebiotic properties of LOSs by the gut microbiota of male Balb/C mice in vivo and in vitro were studied. In vivo experiment results showed that LOS4 could significantly increase the average daily food consumption, weight, liver index and the abundance of Bacteroides and Bifidobacterium for mice (p < 0.05). In addition, LOS4 also had significant proliferation effect on Bifidobacterium adolescentis and longum in vitro (p < 0.05). Laser confocal microscopy observation showed interaction site between LOS4-FITC and Bifidobacterium adolescentis was located outside and inside of cell, which was completed within 1 h. The relationship between structures of LOSs and prebiotics of intestinal flora (especially Bifidobacterium), and expanded the knowledge on the effects of carbohydrate polymerization degree (DP) and glycosidic bond connection with fermentation selectivity of bacteria was studied., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The objectives of this study were (1) to investigate the effect of extracts from some plants in the families Nelumbonaceae and Nymphaeaceae on phosphodiesterase 5 (PDE5) and arginase, which have been used in erectile dysfunction treatment, and (2) to isolate and identify the compounds responsible for such activities. The characterization and quantitative analysis of flavonoid constituents in the active extracts were performed by HPLC. Thirty-seven ethanolic extracts from different parts of plants in the genus Nymphaea and Victoria of Nymphaeaceae and genus Nelumbo of Nelumbonaceae were screened for PDE5 and arginase inhibitory activities. The ethanolic extracts of the receptacles and pollens of Nelumbo nucifera Gaertn., petals of Nymphaea cyanea Roxb. ex G.Don, Nymphaea stellata Willd., and Victoria amazonica (Poepp.) Sowerby and the petals and receptacles of Nymphaea pubescens Willd. showed IC 50 values on PDE5 of less than 25 μg/mL while none of the extracts showed effects on arginase. The most active extract, N. pubescens petal extract, was fractionated to isolate and identify the PDE5 inhibitors. The results showed that six flavonoid constituents including quercetin 3'-O- β -xylopyranoside ( 1 ), quercetin 3-methyl ether 3'-O- β -xylopyranoside ( 2 ), quercetin ( 3 ), 3- O -methylquercetin ( 4 ), kaempferol ( 5 ) and 3- O -methylkaempferol ( 6 ) inhibited PDE5 with IC 50 values at the micromolar level.

The lotus (Nelumbonaceae: Nelumbo Adans.) is a highly desired ornamental plant, comprising only two extant species, the sacred lotus (N. nucifera Gaerten.) with red flowers and the American lotus (N. lutea Willd.) with yellow flowers. Flower color is the most obvious difference of two species. To better understand the mechanism of flower color differentiation, the content of anthocyanins and the expression levels of four key structural genes (e.g., DFR, ANS, UFGT and GST) were analyzed in two species. Our results revealed that anthocyanins were detected in red flowers, not yellow flowers. Expression analysis showed that no transcripts of GST gene and low expression level of three UFGT genes were detected in yellow flowers. In addition, three regulatory genes (NnMYB5, NnbHLH1 and NnTTG1) were isolated from red flowers and showed a high similarity to corresponding regulatory genes of other species. Sequence analysis of MYB5, bHLH1 and TTG1 in two species revealed striking differences in coding region and promoter region of MYB5 gene. Population analysis identified three MYB5 variants in Nelumbo: a functional allele existed in red flowers and two inactive forms existed in yellow flowers. This result revealed that there was an association between allelic variation in MYB5 gene and flower color difference. Yeast two-hybrid experiments showed that NnMYB5 interacts with NnbHLH1, NlbHLH1 and NnTTG1, and NnTTG1 also interacts with NnbHLH1 and NlbHLH1. The over-expression of NnMYB5 led to anthocyanin accumulation in immature seeds and flower stalks and up-regulation of expression of TT19 in Arabidopsis. Therefore, NnMYB5 is a transcription activator of anthocyanin synthesis. This study helps to elucidate the function of NnMYB5 and will contribute to clarify the mechanism of flower coloration and genetic engineering of flower color in lotus.