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Five homologous lotus parts, namely, the leaf, stamen, plumule, flower and leaf base, are all ancient nutrient sources, but their chemical differences are poorly understood. Identification of these parts of origin could contribute to determining reasonable edible and/or medicinal applications without misuse/waste risk. The present work aimed to investigate the feasibility of using metabolic profiles coupled with explainable machine learning (ML) for tracing lotus parts of origin. Assisted with molecular networking, 151 compounds were systematically annotated through an untargeted metabolomics approach. Twenty-eight representative constituents were subsequently quantified for the construction of the ML algorithm. Because most ML algorithms are data-driven black boxes with opaque inner workings, the SHaply Additive exPlanation technique was innovatively used to understand model outputs. By offering an integral analytical platform for phytochemical characterization and information interpretation, these results could serve as a basis for an explainable tool for identification of the specific lotus part of origin.

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.

In the present study, lotus seed oligosaccharides (LOSs) were isolated from lotus (Nelumbo nucifera Gaertn.) seeds using preparative liquid chromatography. LOS structures were characterized using fourier transform infrared spectroscopy (FT-IR), acid hydrolysis, tandemmass spectrometry (MS/MS) and 1D/2D nuclear magnetic resonance (NMR) spectroscopy. Then, Lactobacillus acidophilus was used to evaluate the prebiotic activity of LOSs in vitro. The structural analysis revealed that the monosaccharide components of LOSs included glucose, mannose, fructose and galactose. The MS/MS results indicated that disaccharides, trisaccharides, trisaccharides and tetrasaccharides were the constituents of isolated oligosaccharide polymers LOS2, LOS3-1, LOS3-2, and LOS4, respectively. The FT-IR and 1D/2D NMR data confirmed that LOS3 and LOS4 had a linear structure consisting of (1 → 6)-α-d-mannopyranosyl and glucopyranosyl residues. LOS3-1 and LOS4 effectively and selectively promoted the growth of an L. acidophilus strain, according to the results of the assays of optical density and the short-chain fatty acid (SCFA) content in the culture broth.

By inspecting starch hierarchical structural evolution, this work explored how microwave irradiation tailored the digestion characteristics of lotus seed starch-chlorogenic acid mixtures. The results showed that after microwave treatment, the granular structure, short-range ordered structure, helical conformation, and lamellar structure of starch exhibited different degrees of disorganization. In this procedure, chlorogenic acid interacted with starch molecules to form lotus seed starch-chlorogenic acid complexes and participated in the reorganization of the matrixes of the starch substrate in three forms: V-type inclusion complex, non-inclusion complex, and simply physically entrapped. These structural changes, coupled with the inhibition of chlorogenic acid on carbohydrate hydrolyzing enzymes, contributed to the slowly digestible features of lotus seed starch-chlorogenic acid complexes. This study provided a basis for understanding the multi-scale structure-digestibility relationship of starchy foods rich in phenolic acids under microwave treatment.

Post-cut surface browning is one of the major constraints for shelf-life extension of lotus root slices. In the present study, lotus roots slices were treated with 0, 5 and 10 mmol L−1 oxalic acid and stored at 20 ± 1 °C for 5 days. Results showed that 10 mmol L−1 oxalic acid treated lotus slices exhibited reduced browning, superoxide anion, hydrogen peroxide, electrolyte leakage and malondialdehyde content than control. The 10 mmol L−1 treated slices had better visual quality and higher ascorbic acid and total phenolic contents. In addition, 10 mmol L−1 treated slices showed reduced total bacterial count along with lower soluble quinones, peroxidase and polyphenol oxidase activities in contrast to control. Similarly, 10 mmol L−1 treatment showed higher superoxide dismutase, catalase and ascorbate peroxidase activities as compared to control. In conclusion, 10 mmol L−1 oxalic acid application could be considered suitable to delay post-cut browning of lotus root slices.

Lotus root (Nelumbo nucifera G.) is a high economic value crop in the world. In this study, the storage characteristics (color, sensory, texture, and fatty acids) of lotus root (“Elian No.5″) were evaluated at different harvest periods (September 2018, October 2018, November 2018, December 2018, and January 2019). Moreover, the storage characteristics were evaluated after the short- term and long-term storage of lotus root at 4 °C and 20 °C. The hardness of lotus root significantly decreased at both temperatures (4 °C and 20 °C) during the first 3 days of storage. In contrast, the decrease in hardness delayed at 4 °C (beyond 3 days of storage). Further, genes related to hardness at different storage temperatures were identified using the RNA-seq and qRT-PCR. The results of this study provide a reference for lotus root storage and a basis for the molecular breeding of longterm-storable lotus root.

Pretreatments such as low temperature blanching and/or calcium soaking affect the cooked texture of vegetal food. In the work, lotus rhizomes (Nelumbo nucifera Gaertn.) were pretreated using the following 4 treatments, blanching at 40°C, blanching at 90°C, soaking in 0.5% CaCl2, and blanching at 40°C followed by immersion in 0.5% CaCl2. Subsequently, the cell wall material of pretreated samples was isolated and fractioned to identify changes in the degree of esterification (DE) and monosaccharide content of each section, and the texture of the lotus rhizomes in different pre-treatments was determined after thermal processing with different time. The results showed that the greatest hardness was obtained after blanching at 40°C in CaCl2, possibly attributing to the formation of a pectate calcium network, which maintains the integrity of cell walls. Furthermore, the content of galactose, rhamnose and arabinose decreased due to the breakage of sugar backbones and subsequent damage to cell walls. Our results may provide a reference for lotus rhizome processing.

Lotus seed kernel (LSK) has high starch content and possesses many bioactivities, which are mainly attributed to its phenolics. In the present study, LSK phenolics were extracted using aqueous glycerol, and the obtained phenolics and its starch properties were observed for their correlations. Response surface methodology indicated significant quadratic effect of temperature and significant linear effect of glycerol on LSK phenolics (p

Macroporous resins have been employed in the effective recovery of flavonoids from plants. In this study, S8 polar resins were used to recover flavonoids and procyanidins from lotus seedpods. Adsorption kinetics, isotherms, and thermodynamics studies revealed that the adsorption process involved physico-chemical interactions, including flavonoid-resin and flavonoid-flavonoid electrostatic interactions, π-π aromatic stacking, moderate and strong hydrogen bonding, and repulsive forces. These forces worked complementarily in adsorption, except for the repulsive force, which opposed the adsorption. Further, adsorption temperature determined the adsorption behavior, with multilayer adsorption enhancing adsorption capacity. In dynamic desorption tests, an acetone/water/acetic acid mixture (58.77: 39.34: 1.89) designed by the D-optimal design method was able to desorb 95.57% and 89.85% of total flavonoids and procyanidins, respectively, using less than two bed volumes of solvent. Ultra-performance liquid chromatography triple-time of flight/mass spectrometry (UPLC-TOF/MS) analysis showed that 26 flavonoids, including 5 procyanidins, were detected after the recovery.

Previously we have reported that neferine from the medicinal plant Nelumbo nucifera, inhibited cancer cell proliferation by inducing apoptosis. The present study was focused on the action mechanism of neferine in inducing autophagy in lung cancer cells. Neferine markedly inhibited A549 cell proliferation in a dose dependent manner. Acidic vesicular accumulation was observed in neferine treated cells as an indication of autophagy. Neferine could induce the conversion of LC3B-I to LC3B-II without affecting the expression levels of PI3KCIII and Beclin1. It has been observed that neferine mediated autophagy is dependent on inhibition of PI3K/Akt/mTOR signaling by neferine. Neferine treatment could also lead to the ROS hypergeneration and depletion of cellular antioxidant, GSH. The results demonstrate that neferine-induced autophagy is mediated through ROS hypergeneration and mTOR inhibition. Taken together, the present study unveils a novel mechanism of action of neferine on lung cancer cells in the induction of autophagy.

Petal colour is one of the major characteristics that determine the ornamental value of lotus. To assess the contribution of different flavonoids to this character, composition and content of anthocyanins, flavones and flavonols were analysed through high performance liquid chromatography coupled with photodiode array detection tandem electrospray ionisation triple quad mass spectrometry in 108 lotus cultivars with red, pink, yellow, white and red/white pied petal colours. Totally, five anthocyanins and fourteen flavones and flavonols were detected and quantified. In general, the yellow, white and pied species hardly contained any anthocyanins; red cultivars contain more than pink cultivars. Among the five anthocyanins, malvidin 3-O-glucoside was the most abundant one in all the cultivars that contain anthocyanin. The fourteen flavones and flavonols belonged to four groups based on their aglycones. Except for the yellow cultivars, kaempferol-derivatives were the most abundant one. These data might be helpful in lotus breeding for different colours.

Evidence has accumulated concerning the medicinal application of Nelumbo nucifera in the treatment of various diseases. Neferine, an alkaloid from N. nucifera was found to exert cytotoxicity on liver cancer cells HepG2 in a dose-dependent manner. We evaluated its anticancer potential by studying its effect on mitochondrial membrane potential, intracellular calcium levels [Ca(2+)](i), cell membrane integrity, apoptotic body formation and DNA fragmentation in cultured HepG2 cells. The reactive oxygen species level has been increased upon neferine treatment with concomitant decrease in reduced glutathione. Our data further indicate reduction of ΔψM and increased [Ca(2+)](i) during apoptosis induction by neferine with increased expression of apoptotic proteins such as Bax, Bad, cleaved forms of caspase 3, caspase 9 and PARP, with the downregulation of anti-apoptotic protein Bcl2 in HepG2 cells. Moreover, the expressions of tumour suppressor proteins p53 and PTEN were upregulated along with the downregulation of P-Akt. In addition, expression levels of TNF-α, p38 and ERK1/2 MAP kinases were increased upon neferine treatment. These results imply that mitochondrial-mediated ROS generation induced by neferine leads to caspase-dependent apoptosis in HepG2 cells.

The effects of boiling and steaming on lotus root volatile compounds and some of its physicochemical properties were determined. A total of 52 compounds identified in the raw tuber by GC-MS were a combination of the rhizome's native compounds and those from the soil and water environment, and are predominantly a mixture of straight chain and cyclic alkanes, and aromatic hydrocarbons. Boiling increased concentrations of most of these compounds, unlike steaming that lowered total volatile components of the tuber. Cooking increased complexity of volatile compounds with the production of new compounds such as methylated derivatives, particularly in steam cooked lotus. Other heat-induced compounds include antioxidants such as butylated hydroxyl compounds and antifungal organic compounds such as dimethyl disulfide. Instrumental texture measurements indicate that the characteristic post-cooked retention of crunchiness in lotus root is likely to be related to retention of its springiness index through the cooking process.

A novel lotus plumule polysaccharide (LPPS) was purified, characterised and cultured with RAW264.7 macrophages to evaluate its anti-inflammatory characteristics. LPPS was purified using Sepharose 6B gel filtration and dissolved into two major components, fraction-1 (F1) and fraction-2 (F2). The molecular weights of native F1 and F2 were approximately distributed at >2,000 and 25.7kDa, respectively. The total protein and carbohydrate constituent ratios in LPPS, F1, and F2 were 30.0±0.9% vs. 70.0±0.9%, 30.1±2.6% vs. 69.9±2.6%, and 96.5±6.1% vs. 3.5±6.1% (w/w), respectively, suggesting that F1 may be a major proteo-polysaccharide component and F2 a glycoprotein constituent in LPPS. Pro-/anti-inflammatory (IL-6/IL-10) cytokine secretion ratios by lipopolysaccharide-stimulated RAW264.7 macrophages were significantly decreased by F1 and F2 treatments, particularly by F2, in a dose-dependent manner under a preventive experimental model. This study suggests that purified components, F1 and F2 from LPPS, have strong anti-inflammatory effects on LPS-induced inflamed macrophages in a preventive manner.

The inhibitory effect of lotus ( Nelumbo nicifera ) seed extracts extracted with water (LSWE), ethyl acetate (LSEAE) and hexane (LSHE) on reactive nitrogen species, induced by DNA damage in macrophage RAW 264.7 cells, was investigated. The results showed that all extracts could inhibit nitric oxide accumulation in LPS-activated RAW 264.7 cells. The extracts in the range of 0.01–0.2 mg/ml showed a dose-dependent inhibitory effect on the accumulation of nitric oxide upon decomposition of sodium nitroprusside (SNP). The potency of inhibitory activity was in the order: LSEAE > LSWE > LSHE. The results of the comet assay indicated that the three extracts could inhibit DNA damage in macrophage RAW 264.7 cells induced by SNP. In addition, the three samples, at 0.2 mg/ml, showed 63%, 59%, and 38% inhibition of DNA damage in macrophage RAW 264.7 cells induced by peroxynitrite, respectively. All extracts tested were found to be potent peroxynitrite scavengers, capable of preventing the nitration of tyrosine. The data obtained suggest that lotus seed extracts might act as chemopreventers through reduction of excess amounts of nitric oxide.

Extracts from rhizomes (Lotus roots) knot (LRK) and whole rhizomes (LR) were investigated for their antioxidative capacity in comparison with commonly used antioxidants from plant material. Radical scavenging activity was measured spectrophotometrically using the stable radicals 1-diphenyl-2-picrylhydrazyl and 2,2′-azino(3-ethylbenzothioazolino-6-sulfonate), and measured by electron spin resonance (ESR) trapping of the transient carbon-centered 1-hydroxyethyl radical (generated in a Fenton-type reaction). Efficiencies as chain-breaking antioxidants were evaluated by electrochemical measurement of oxygen consumption rate in a peroxidating methyl linoleate emulsion. LRK exhibited high antioxidative capacity, as measured by each of four different methods. LR, however, only showed a significantly high scavenging activity for small carbon-centered radicals, as measured by the ESR method. Total phenol content in the plant extract correlated with the antioxidant capacity, except for the scavenging of carbon-centered radical. Lotus rhizomes knot, as a waste from food production, will be a potential material for extracting antioxidants.