Bisbenzylisoquinoline Alkaloids from Nelumbo nucifera

Concise and Modular Chemoenzymatic Total Synthesis of Bisbenzylisoquinoline Alkaloids

The bisbenzylisoquinoline alkaloids (bisBIAs) have attracted tremendous attention from the synthetic community due to their diverse and intriguing biological activities. Herein, we report the convergent and modular chemoenzymatic syntheses of eight bisBIAs bearing various substitutes and linkages in 5-7 steps. The gram-scale synthesis of various well-designed enantiopure benzylisoquinoline monomers was accomplished through an enzymatic stereoselective Pictet-Spengler reaction, followed by regioselective enzymatic methylation or chemical functionalization in a sequential one-pot process. A modified intermolecular copper-mediated Ullmann coupling enabled the concise and efficient total synthesis of five different linear bisBIAs with either head-to-tail or tail-to-tail linkage. A biomimetic oxidative phenol dimerization selectively formed the sterically hindered, electron-rich diaryl ether bond, and subsequent intramolecular Suzuki-Miyaura domino reaction or Ullmann coupling facilitated the first enantioselective total synthesis of three macrocyclic bisBIAs, including ent-isogranjine, tetrandrine and O-methylrepandine. This study highlights the great potential of chemoenzymatic strategies in the total synthesis of diverse bisBIAs and paves the way to further explore the biological functions of these natural products.

Structurally Diverse Bisbenzylisoquinoline Alkaloids with Antiadipogenic Activity through PPARγ Downregulation from the Embryo of Nelumbo nucifera Seeds

Six undescribed and six known bisbenzylisoquinoline alkaloids were isolated from the embryo of Nelumbo nucifera seeds. Their structures were fully characterized by a combination of 1H, 13C NMR, 2D NMR, and HRESIMS analyses, as well as ECD computational calculations. The antiadipogenic activity of 11 alkaloids was observed in a dose-responsive manner, leading to the suppression of lipid accumulation in 3T3-L1 cells. Luciferase assay and Western blot analysis showed that the active alkaloids downregulated peroxisome proliferator-activated receptor gamma (PPARγ, a key antiadipogenic receptor) expression in 3T3-L1 cells. Analysis of the structure-activity relationship unveiled that a 1R,1'S configuration in bisbenzylisoquinoline alkaloids led to a notable enhancement in antiadipogenic activity. The resistance level against lipid accumulation highlighted a consistent pattern with the suppressive effect on the PPARγ expression. These activity results indicate that alkaloids from the embryo of N. nucifera seeds have a potential of antiobesity effects through PPARγ downregulation.

Isoliensinine Attenuates Renal Fibrosis and Inhibits TGF-β1/Smad2/3 Signaling Pathway in Spontaneously Hypertensive Rats

Purpose

This study aimed to investigate the molecular mechanisms of isoliensinine, a kind of bibenzyl isoquinoline alkaloid which isolated from a TCM named Lotus Plumule (Nelumbo nucifera Gaertn), in treating renal interstitial fibrosis (RIF) by using RNA sequencing, KEGG analysis and in vivo experimental approaches.

Methods

Spontaneous hypertension rats (SHRs) were randomly assigned into five groups, consisting of SHR, SHR+Isoliensinine-L (2.5 mg/kg/day), SHR+Isoliensinine-M (5 mg/kg/day), SHR+Isoliensinine-H (10 mg/kg/day), and SHR+Valsartan (10 mg/kg/day) groups (n = 6 for each group). A control group of Wistar Kyoto rats (n = 6) was also included. Rats were treated intragastrically with isoliensinine, valsartan, or double-distilled water of equal volume for 10 weeks. To examine the therapeutic impact on hypertensive renal injury, fibrosis, and its underlying mechanisms, multiple techniques were employed, including hematoxylin and eosin staining, Masson trichrome staining, RNA sequencing, gene ontology (GO) function and pathway enrichment analysis and immunohistochemistry.

Results

Resultantly, the use of isoliensinine at different concentrations or valsartan showed significant improvement in renal pathological injury in SHRs. RNA sequencing and KEGG analysis uncovered 583 differentially expressed transcripts and pathways enriched in collagen formation and ECM-receptor interaction after treatment with isoliensinine. There was also a reduction in the increase of collagen and upregulation of collagen I & III, TGF-β1, p-Smad2, and p-Smad3 in the renal tissue of SHRs. Thus, isoliensinine ameliorated renal injury and collagen deposition in hypertensive rats, and inhibiting the activation of the TGF-β1/Smad2/3 pathway might be one of the underlying mechanisms.

Conclusion

This study showed that treatment with isoliensinine effectively reduced the renal injury and fibrosis in SHRs. In addition, isoliensinine inhibited the TGF-β1/Smad2/3 signaling in-vivo. These findings provided strong evidence for the therapeutic benefits of isoliensinine in combating renal injury and fibrosis.

Bisbenzylisoquinoline alkaloids from Plumula Nelumbinis inhibit vascular smooth muscle cells migration and proliferation by regulating the ORAI2/Akt pathway

Plumula Nelumbinis, the embryo of the seed of Nelumbo nucifera Gaertn, is commonly used to make tea and nutritional supplements in East Asian countries. A bioassay-guided isolation of Plumula Nelumbinis afforded six previously undescribed bisbenzylisoquinoline alkaloids, as well as seven known alkaloids. Their structures were elucidated by extensive analysis of HRESIMS, NMR, and CD data. Pycnarrhine, neferine-2α,2'β-N,N-dioxides, neferine, linsinine, isolinsinine, and nelumboferine, at 2 μM significantly suppressed the migration of MOVAS cells with inhibition ratio above 50%, more active than that of the positive control cinnamaldehyde (inhibition ratio 26.9 ± 4.92%). Additionally, neferine, linsinine, isolinsinine, and nelumboferine, were also active against the proliferation of MOVAS cells with inhibition ratio greater than 45%. The preliminary structure-activity relationships were discussed. Mechanism studies revealed that nelumboferine inhibited the migration and proliferation of MOVAS cells by regulating ORAI2/Akt signaling pathway.

Recent advances on bioactive compounds, biosynthesis mechanism, and physiological functions of Nelumbo nucifera

Nelumbo nucifera Gaertn, commonly known as lotus, is a genus comprising perennial and rhizomatous aquatic plants, found throughout Asia and Australia. This review aimed to cover the biosynthesis of flavonoids, alkaloids, and lipids in plants and their types in different parts of lotus. This review also examined the physiological functions of bioactive compounds in lotus and the extracts from different organs of the lotus plant. The structures and identities of flavonoids, alkaloids, and lipids in different parts of lotus as well as their biosynthesis were illustrated and updated. In the traditional medicine systems and previous scientific studies, bioactive compounds and the extracts of lotus have been applied for treating inflammation, cancer, liver disease, Alzheimer's disease, etc. We suggest future studies to be focused on standardization of the extract of lotus, and their pharmacological mechanisms as drugs or functional foods. This review is important for the lotus-based food processing and application.

Liensinine, a alkaloid from lotus plumule, mitigates lipopolysaccharide-induced sepsis-associated encephalopathy through modulation of nuclear factor erythroid 2-related factor-mediated inflammatory biomarkers and mitochondria apoptosis

The present study aims to investigate the role of liensinine in life-threatened sepsis-associated encephalopathy (SAE) mice and the underlying mechanism. Here, seventy-two mice were divided into six groups, including the control group, SAE group, liensinine-treated group, and three doses of liensinine-treated SAE groups. Lipopolysaccharide triggered cerebrum necrosis and disrupted the integrity and permeability of blood-brain barrier (BBB). While liensinine restored cerebrum structure and improved BBB integrity with upregulated tight junction proteins, decreased evans blue leakage and fibrinogen expression with decreased matrix metalloproteinases 2/9 in serum, thereby reducing BBB permeability. Moreover, lipopolysaccharide triggered cerebrum oxidative stress and inflammation, whereas liensinine enhanced antioxidant enzymes activities and weakened malondialdehyde through nuclear factor erythroid 2-related factor. Meanwhile, liensinine inhibited inflammation by activating inducible nitric oxide synthase. Tunel staining combined with transmission electron microscope indicated that lipopolysaccharide induced cerebrum apoptosis, whereas liensinine blocked apoptosis through decreasing B-cell lymphoma-2 associated X (Bax) expression and cytochrome C (Cyto-c) release, increasing B-cell lymphoma-2 (Bcl-2) expression, blocking apoptosome assembly, inhibiting caspase-3 activation, thereby suppressing intrinsic mitochondria apoptosis. Recovering of inflammatory homeostasis and inhibition of mitochondria apoptosis by liensinine ultimately restored cognitive function in SAE mice. Altogether, liensinine attenuated lipopolysaccharide-induced SAE via modulation of Nrf2-mediated inflammatory biomarkers and mitochondria apoptosis.

Isolation and Characterization of the Genes Involved in the Berberine Synthesis Pathway in Asian Blue Cohosh, Caulophyllum robustum

Caulophyllum robustum, commonly named Asian blue cohosh, is a perennial herb in the family Berberidaceae. It has traditionally been used for folk medicine in China. We isolated berberine from the leaves, stem, roots, and fruits of C. robustum, and this is the first report on berberine in this species. Transcriptome analysis was conducted for the characterization of berberine biosynthesis genes in C. robustum, in which, all the genes for berberine biosynthesis were identified. From 40,094 transcripts, using gene ontology (GO) analysis, 26,750 transcripts were assigned their functions in the categories of biological process, molecular function, and cellular component. In the analysis of genes expressed in different tissues, the numbers of genes in the categories of intrinsic component of membrane and transferase activity were up-regulated in leaves versus stem. The berberine synthesis genes in C. robustum were characterized by phylogenetic analysis with corresponding genes from other berberine-producing species. The co-existence of genes from different plant families in the deepest branch subclade implies that the differentiation of berberine synthesis genes occurred early in the evolution of berberine-producing plants. Furthermore, the copy number increment of the berberine synthesis genes was detected at the species level.

Pathway elucidation and microbial synthesis of proaporphine and bis-benzylisoquinoline alkaloids from sacred lotus (Nelumbo nucifera)

Sacred lotus (Nelumbo nucifera) has been utilized as a food, medicine, and spiritual symbol for nearly 3000 years. The medicinal properties of lotus are largely attributed to its unique profile of benzylisoquinoline alkaloids (BIAs), which includes potential anti-cancer, anti-malarial and anti-arrhythmic compounds. BIA biosynthesis in sacred lotus differs markedly from that of opium poppy and other members of the Ranunculales, most notably in an abundance of BIAs possessing the (R)-stereochemical configuration and the absence of reticuline, a major branchpoint intermediate in most BIA producers. Owing to these unique metabolic features and the pharmacological potential of lotus, we set out to elucidate the BIA biosynthesis network in N. nucifera. Here we show that lotus CYP80G (NnCYP80G) and a superior ortholog from Peruvian nutmeg (Laurelia sempervirens; LsCYP80G) stereospecifically convert (R)-N-methylcoclaurine to the proaporphine alkaloid glaziovine, which is subsequently methylated to pronuciferine, the presumed precursor to nuciferine. While sacred lotus employs a dedicated (R)-route to aporphine alkaloids from (R)-norcoclaurine, we implemented an artificial stereochemical inversion approach to flip the stereochemistry of the core BIA pathway. Exploiting the unique substrate specificity of dehydroreticuline synthase from common poppy (Papaver rhoeas) and pairing it with dehydroreticuline reductase enabled de novo synthesis of (R)-N-methylcoclaurine from (S)-norcoclaurine and its subsequent conversion to pronuciferine. We leveraged our stereochemical inversion approach to also elucidate the role of NnCYP80A in sacred lotus metabolism, which we show catalyzes the stereospecific formation of the bis-BIA nelumboferine. Screening our collection of 66 plant O-methyltransferases enabled conversion of nelumboferine to liensinine, a potential anti-cancer bis-BIA from sacred lotus. Our work highlights the unique benzylisoquinoline metabolism of N. nucifera and enables the targeted overproduction of potential lotus pharmaceuticals using engineered microbial systems.

Elucidation of the (R)-enantiospecific benzylisoquinoline alkaloid biosynthetic pathways in sacred lotus (Nelumbo nucifera)

Benzylisoquinoline alkaloids (BIAs) are a structurally diverse group of plant specialized metabolites found mainly in members of the order Ranunculales, including opium poppy (Papaver somniferum), for which BIA biosynthetic pathways leading to the critical drugs morphine, noscapine, and sanguinarine have been elucidated. Sacred lotus (Nelumbo nucifera), in the order Proteales, accumulates medicinal BIAs in the proaporphine, aporphine, and bisbenzylisoquinoline structural subgroups with a prevalence of R enantiomers, opposed to the dominant S configuration occurring in the Ranunculales. Nevertheless, distinctive BIA biosynthetic routes in sacred lotus have not been explored. In planta labeling experiments and in vitro assays with recombinant enzymes and plant protein extracts showed that dopamine and 4-hydroxyphenylacetaldehyde derived from L-tyrosine serve as precursors for the formation of (R,S)-norcoclaurine in sacred lotus, whereas only (R)-norcoclaurine byproducts are favored in the plant by action of R-enantiospecific methyltransferases and cytochrome P450 oxidoreductases (CYPs). Enzymes responsible for the R-enantiospecific formation of proaporphine (NnCYP80Q1) and bisbenzylisoquinoline (NnCYP80Q2) scaffolds, and a methylenedioxy bridge introduction on aporphine substrates (NnCYP719A22) were identified, whereas additional aspects of the biosynthetic pathways leading to the distinctive alkaloid profile are discussed. This work expands the availability of molecular tools that can be deployed in synthetic biology platforms for the production of high-value alkaloids.

Neferine ameliorates hypertensive vascular remodeling modulating multiple signaling pathways in spontaneously hypertensive rats

BACKGROUND

Neferine exhibits therapeutic effects on anti-hypertension. However, the effect of neferine on hypertensive vascular remodeling remains unexplored. Therefore, the current study was to investigate the effect of neferine on hypertensive vascular remodeling and its underlying mechanisms.

METHODS

Total 30 male spontaneously hypertensive rats (SHRs) were divided randomly into five groups, including SHR, Neferine-L (2.5 mg/kg/day), Neferine-M (5 mg/kg/day), Neferine-H (10 mg/kg/day), and Valsartan (10 mg/kg/day) groups (n = 6 for each group). Wistar Kyoto (WKY) rats were set as control group (n = 6). Noninvasive blood pressure system, ultrasound, hematoxylin and eosin staining, masson trichrome staining were used to detect the blood pressure, pulse wave velocity (PWV), pathological changes and collagen content in abdominal aortas of SHRs. RNA-sequencing and immunohistochemistry(IHC) analyses were used to identify and verify the differentially expressed transcripts and activation of associated signaling pathways in SHRs.

RESULTS

Various concentrations of neferine or valsartan treatment substantially reduced the elevation of blood pressure, PWV, and abdominal aortic thickening of SHRs. RNA-sequencing and KEGG analyses recognized 441 differentially expressed transcripts and several enriched pathways (including PI3K/AKT and TGF-β/Smad2/3 signaling pathways) after neferine treatment. Masson trichromatic staining and IHC analysis demonstrated that neferine treatment decreased the collagen content and down-regulated the protein expression of PCNA, collagen I & III, and fibronectin, as well as p-PI3K, p-AKT, TGF-β1 and p-Smad2/3 in abdominal aortic tissues of SHRs.

CONCLUSION

Neferine treatment exhibits therapeutic effects on anti-hypertension and reduces vascular remodeling, as well as suppresses the abnormal activation of multiple signaling pathways, including PI3K/AKT and TGF-β1/Smad2/3 pathways.

Dietary higenamine from Annonaceae family fruits as a possible source of unintentional doping

Members of the genus Aconitum have been used for millennia, both as poisons and medicines, in Eastern culture. Higenamine has non-selective beta-agonist effects, activating both β₁ and β₂ adrenoreceptors, and is present in a variety of plants. The World Anti-Doping Agency has banned Higenamine both in competition and out of competition. Due to the common uses of higenamine in Brazilian culture, both as medicine and food, we studied the urinary concentrations of higenamine after the consumption of fruits of the Annona genus. We evaluated whether the ingestion of these fruits has the potential to cause anti-doping code violations. We measured higenamine concentrations for a 72 h period in the urine of ten healthy, physically active males (age 20-30; weight 70-80 kg; not consuming supplements or medications) after eating a unique meal containing fruits. Fruit consumption ranges were: Carica papaya (control) 348 ± 98 g; A. muricata 450 ± 282 g; and A. squamosa 314 ± 60 g. (all mean± SD). Higenamine was measured using ultra-performance liquid chromatography coupled with electrospray-tandem mass spectrometry. The appearance of urinary higenamine occurred within the first 12 h after eating A. muricata (n = 3), and the maximum concentration found was 1.9 ng/mL. The ingestion of A. squamosa has also been shown to cause higenamine urinary excretion. The elimination kinetics of the subjects who ingested A. squamosa (n = 4) were different from each other. After ingestion of the control fruit, C. papaya, we detected no higenamine in the urine of any participants (n = 3). Although the kinetics varied by individuals and fruits, A. muricata ingestion produced higher higenamine excretion; however, the A. squamosa portion weighed ∼66 % of the A. muricata portion. We conclude that eating Annonaceae family fruits cause detectable higenamine excretion. Conversely, single ingestion did not reach the WADA's threshold to cause adverse analytical findings.

Indigenous Uses, Phytochemical Analysis, and Anti-Inflammatory Properties of Australian Tropical Medicinal Plants

Australian tropical plants have been a rich source of food (bush food) and medicine to the first Australians (Aboriginal people), who are believed to have lived for more than 50,000 years. Plants such as spreading sneezeweed (Centipeda minima), goat’s foot (Ipomoea pes-caprae), and hop bush (Dodonaea viscosa and D. polyandra) are a few popular Aboriginal medicinal plants. Thus far, more than 900 medicinal plants have been recorded in the tropical region alone, and many of them are associated with diverse ethnomedicinal uses that belong to the traditional owners of Aboriginal people. In our effort to find anti-inflammatory lead compounds in collaboration with Aboriginal communities from their medicinal plants, we reviewed 78 medicinal plants used against various inflammation and inflammatory-related conditions by Aboriginal people. Out of those 78 species, we have included only 45 species whose crude extracts or isolated pure compounds showed anti-inflammatory properties. Upon investigating compounds isolated from 40 species (for five species, only crude extracts were studied), 83 compounds were associated with various anti-inflammatory properties. Alphitolic acid, Betulinic acid, Malabaric acid, and Hispidulin reduced proinflammatory cytokines and cyclooxygenase enzymes (COX-1 and 2) with IC₅₀ values ranging from 11.5 to 46.9 uM. Other promising anti-inflammatory compounds are Brevilin A (from Centipeda minima), Eupalestin, and 5′-methoxy nobiletin (from Ageratum conyzoides), Calophyllolide (from Calophyllum inophyllum), and Brusatol (from Brucea javanica). D. polyandra is one example of an Aboriginal medicinal plant from which a novel anti-inflammatory benzoyl ester clerodane diterpenoid compound was obtained (compound name not disclosed), and it is in the development of topical medicines for inflammatory skin diseases. Medicinal plants in the tropics and those associated with indigenous knowledge of Aboriginal people could be a potential alternative source of novel anti-inflammatory therapeutics.

Rapid-Onset Antidepressant-Like Effect of Nelumbinis semen in Social Hierarchy Stress Model of Depression

Depression is a disease with increasing prevalence worldwide, and it is necessary to develop a therapeutic agent with better efficacy than existing antidepressant drugs. Antidepressants that act on the glutamatergic nervous system, such as ketamine, have a rapid-onset antidepressant effect and are effective against treatment-resistant depression. However, because of the addictive potential of ketamine, alternative substances without psychological side effects are recommended. In particular, many natural compounds have been tested for their antidepressant effects. The antidepressant effects of Nelumbinis semen (NS) have been tested in many studies, along with the various actions of NS on the glutamatergic system. Thus, it was expected that NS might have a rapid-onset antidepressant effect. To test the antidepressant potential, despair and anhedonic behaviors were measured after administering NS to mice exposed to social hierarchy stress (SHS), and biochemical changes in the prefrontal cortex and hippocampus were analyzed. NS reduced despair-like responses in the forced swim test and tail suspension test. Mice exposed to SHS showed depression-like responses such as increased despair, reduced hedonia, and an anxiety-like response in the novelty suppressed feeding test. NS, but not fluoxetine, improved those depression-like behaviors after acute treatment, and NBQX, an AMPA receptor blocker, inhibited the antidepressant-like effects of NS. The antidepressant-like effect of NS was related to enhanced phosphorylation of mTOR in the prefrontal cortex and dephosphorylation of GluR1 S845 in the hippocampus. Since NS has shown antidepressant-like potential in a preclinical model, it may be considered as a candidate for the development of antidepressants in the future.

Neferine, an Alkaloid from Lotus Seed Embryos, Exerts Antiseizure and Neuroprotective Effects in a Kainic Acid-Induced Seizure Model in Rats

Current anti-seizure drugs fail to control approximately 30% of epilepsies. Therefore, there is a need to develop more effective anti-seizure drugs, and medicinal plants provide an attractive source for new compounds. This study aimed to evaluate the possible anti-seizure and neuroprotective effects of neferine, an alkaloid from the lotus seed embryos of Nelumbo nucifera, in a kainic acid (KA)-induced seizure rat model and its underlying mechanisms. Rats were intraperitoneally (i.p.) administrated neferine (10 and 50 mg/kg) 30 min before KA injection (15 mg/kg, i.p.). Neferine pretreatment increased seizure latency and reduced seizure scores, prevented glutamate elevation and neuronal loss, and increased presynaptic protein synaptophysin and postsynaptic density protein 95 expression in the hippocampi of rats with KA. Neferine pretreatment also decreased glial cell activation and proinflammatory cytokine (interleukin-1β, interleukin-6, tumor necrosis factor-α) expression in the hippocampi of rats with KA. In addition, NOD-like receptor 3 (NLRP3) inflammasome, caspase-1, and interleukin-18 expression levels were decreased in the hippocampi of seizure rats pretreated with neferine. These results indicated that neferine reduced seizure severity, exerted neuroprotective effects, and ameliorated neuroinflammation in the hippocampi of KA-treated rats, possibly by inhibiting NLRP3 inflammasome activation and decreasing inflammatory cytokine secretion. Our findings highlight the potential of neferine as a therapeutic option in the treatment of epilepsy.

Higenamine in Plants as a Source of Unintentional Doping

BACKGROUND

Higenamine is a β2 agonist of plant origin. The compound has been included in WADA's prohibited list since 2017. Higenamine may be detected in different plants and many food supplements of natural origin.

METHODS

Our literature search was conducted through PubMed, Science Direct, Google Scholar, and Web of Science studies investigating the presence of higenamine in plants that are used in traditional folk medicine or included in food supplements. Our study aimed to assess the risk of adverse analytical findings caused by higenamine-containing plants.

RESULTS

Based on our literature search, Nelumbo nucifera, Tinospora crispa, Nandina domestica, Gnetum parvifolium, Asarum siebodii,Asarum heterotropoides, Aconitum carmichaelii, and Aristolochia brasiliensis are higenamine-containing plants. Based on data from Eastern folk medicine, these plants can provide numerous health benefits. Professional athletes likely ingest these plants without knowing that they contain higenamine; these herbs are used in treatments for different conditions and various foods/food supplements in addition to folk medicine.

CONCLUSION

Athletes and their teams must be aware of the issues associated with the use of plant-based products. They should avoid consuming higenamine-containing plants during and outside of competition periods.

Lotus (Nelumbo nucifera Gaertn.) and Its Bioactive Phytocopounds: A Tribute to Cancer Prevention and Intervention

Simple Summary

The plant Nelumbo nucifera (Gaertn.), commonly known as lotus, sacred lotus, Indian lotus, water lily, or Chinese water lily, is an aquatic perennial crop belonging to the family of Nelumbonaceae. N. nucifera has traditionally been used as an herbal medicine and functional food in many parts of Asia. It has been found that different parts of this plant consist of various bioactive phytocompounds. Within the past few decades, N. nucifera and its phytochemicals have been subjected to intense cancer research. In this review, we critically evaluate the potential of N. nucifera phytoconstituents in cancer prevention and therapy with related mechanisms of action.

Abstract

Cancer is one of the major leading causes of death worldwide. Accumulating evidence suggests a strong relationship between specific dietary habits and cancer development. In recent years, a food-based approach for cancer prevention and intervention has been gaining tremendous attention. Among diverse dietary and medicinal plants, lotus (Nelumbo nucifera Gaertn., family Nymphaeaceae), also known as Indian lotus, sacred lotus or Chinese water lily, has the ability to effectively combat this disease. Various parts of N. nucifera have been utilized as a vegetable as well as an herbal medicine for more than 2000 years in the Asian continent. The rhizome and seeds of N. nucifera represent the main edible parts. Different parts of N. nucifera have been traditionally used to manage different disorders, such as fever, inflammation, insomnia, nervous disorders, epilepsy, hypertension, cardiovascular diseases, obesity, and hyperlipidemia. It is believed that numerous bioactive components, including alkaloids, polyphenols, terpenoids, steroids, and glycosides, are responsible for its various biological and pharmacological activities, such as antioxidant, anti-inflammatory, immune-modulatory, antiviral, hepatoprotective, cardioprotective, and hypoglycemic activities. Nevertheless, there is no comprehensive review with an exclusive focus on the anticancer attributes of diverse phytochemicals from different parts of N. nucifera. In this review, we have analyzed the effects of N. nucifera extracts, fractions and pure compounds on various organ-specific cancer cells and tumor models to understand the cancer-preventive and therapeutic potential and underlying cellular and molecular mechanisms of action of this interesting medicinal and dietary plant. In addition, the bioavailability, pharmacokinetics, and possible toxicity of N. nucifera-derived phytochemicals, as well as current limitations, challenges and future research directions, are also presented.

TCPP-Isoliensinine Nanoparticles for Mild-Temperature Photothermal Therapy

Purpose

Photothermal therapy (PTT) is promising for the treatment of tumors due to its advantages including minimally invasive, easy implementation and selective localized treatment. However, single PTT suffers from several limitations, such as constrained light penetration and low delivery efficiency, typically leading to heterogeneous heating and incomplete elimination of cancer cells. Therefore, combination of PTT with other therapies, eg, chemotherapy is desirable in order to achieve synergistic effects in cancer treatment.

Methods

Here, we designed a new type of TCPP-Iso combined nanoparticle for synergetic therapy for breast cancer. Specifically, photothermal agent tetra(4-carboxyphenyl) porphine (TCPP) and anti-cancer drug isoliensinine (Iso) were encapsulated in PEG-b-PLGA polymeric nanoparticles through a precipitation process.

Results

The obtained NPs displayed well-controlled size and high stability over time. Tuning TCPP-Iso/polymer ratio, or total concentration of drug and polymers led to increased hydrodynamic radius of NPs from 65 to 108 nm without disturbing the narrow size distribution. Besides, the formed NPs showed a consequently cumulative release of TCPP and of Iso. The temperature elevation ability of both TCPP NPs and TCPP-Iso NPs was TCPP-concentration dependent. Solutions of TCPP NPs that contained equivalent amount of TCPP with respect to TCPP-Iso NPs, presented the same trend and exhibited non-obvious difference in temperature elevation under certain laser power. The viability of MDA-MB-231 cells treated with TCPP-Iso NPs could be inhibited effectively at a relatively mild temperature (42–43°C) compared to the other groups, which may minimize heat damage to the surrounding healthy tissues.

Conclusion

The results indicate that the TCPP-Iso combined NPs showed hardly any toxicity to normal tissue cell line, but displayed an efficient synergistic effect for killing cancer cells under laser irradiation. Our study demonstrates that the successful combination of TCPP and Iso realized a synergistic therapy effect at a relatively mild temperature, and the insights obtained here shall be helpful for designing new combined PTT agents for cancer treatment.

Lotus seeds (Nelumbinis semen) as an emerging therapeutic seed: A comprehensive review

Nelumbinis semen is commonly known as lotus seeds that have been used as a vegetable, functional food, and medicine for 7,000 years. These are low caloric, a rich source of multiple nutrients and bioactive constituents, which make it a unique therapeutic food. N. semen plays an important part in the physiological functions of the body. Nowadays, people are more conscious about their health and desire to treat disease naturally with minimal side effects. So, functional foods are getting popularity due to a wide range of essential constituents, which are associated to decrease the risk of chronic diseases. These bioactive compounds from seeds are involved in anti-adipogenic, antioxidant, antitumor, cardiovascular, hepato-protective, anti-inflammatory, anti-fertility, anti-microbial, anti-viral, hypoglycemic, etc. Moreover, the relationship between functional compounds along with their mechanism of action in the body, their extraction from the seeds for further research would be of great interest.

Pharmacokinetics, bioavailability and metabolism of neferine in rat by LC-MS/MS and LC-HRMS

In this study, a simple and sensitive analytical method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated for the determination of neferine in rat plasma. After acetonitrile-mediated protein precipitation, the samples were separated on an Acquity BEH C₁₈ column (2.1 × 50 mm, 1.7 μm) maintained at 40°C. The mobile phase comprising 0.1% formic acid in water and acetonitrile was delivered at a flow rate of 0.4 ml/min. The mass detection was conducted using multiple reaction monitoring mode with ion transitions at 625.4 > 206.3 and m/z 622.9 > 380.9 for neferine and internal standard, respectively. The assay was demonstrated to be linear over the concentration range of 0.5-1,000 ng/ml, with correlation coefficient >0.999 (r > 0.999). The validated method was further applied to the pharmacokinetic study of neferine in rat plasma. In addition, the metabolism of neferine was investigated using high-resolution mass spectrometry. A total of six metabolites from rat liver microsomes and plasma were detected and their structures were identified according to their fragment ions. The proposed metabolic pathways of neferine were demethylation, dealkylation, dehydrogenation and glucuronidation.

Plumula Nelumbinis: A review of traditional uses, phytochemistry, pharmacology, pharmacokinetics and safety

ETHNOPHARMACOLOGICAL RELEVANCE

Plumula Nelumbinis, the green embryo of the mature seeds of Nelumbo nucifera Gaertn, has a medical history of over 400 years. It is widely used for clearing the heart and heat, calming the mind, and promoting astringent essence and hemostasis in traditional Chinese medicine. Moreover, it usually dual use as food and medicine. This review aimed to evaluate the therapeutic potential of Plumula Nelumbinis by summarizing its botany, traditional uses, phytochemistry, pharmacology, pharmacokinetics and safety.

METHODS

This review summarized published studies on Plumula Nelumbinis in the Chinese Pharmacopoeia and literature databases including PubMed, Web of Science, Baidu Scholar, Wiley and China Knowledge Resource Integrated Database (CNKI), and limits the different research articles in botany, traditional uses, phytochemistry, pharmacology, pharmacokinetics and safety about Plumula Nelumbinis.

RESULTS

Plumula Nelumbinis is used to treat hypertension, arrhythmia, severe aplastic anemia, insomnia, encephalopathy and gynecological disease in traditional Chinese medicine and clinical studies. More than 130 chemicals have been isolated and identified from Plumula Nelumbinis, including alkaloids, flavonoids, polysaccharides and volatile oil. In addition, pharmacological effects, such as protective effects against cardiovascular diseases, neurological diseases, lung and kidney injury, anti-inflammatory and anticancer activities, were also evaluated by in vitro and in vivo studies. Moreover, the potential signaling pathways regulated by Plumula Nelumbinis in cardiovascular and neurological diseases and perspectives on Plumula Nelumbinis research were discussed.

CONCLUSION

Plumula Nelumbinis, a commonly used Chinese medicine, has a variety of traditional and modern therapeutic uses. Some traditional uses, especially the treatment of cardiovascular and neurological diseases, have been verified by pharmacological investigation. However, the pharmacological molecular mechanisms, pharmacokinetics and toxicology of Plumula Nelumbinis are still incomplete. In the future, a series of systematic studies on active compounds identification, pharmacological mechanism clarification, quality and safety evaluation are necessary.

Neferine improves oxidative stress and apoptosis in benign prostate hyperplasia via Nrf2-ARE pathway

BACKGROUND

Progression of Benign Prostate hyperplasia (BPH) is vulnerable to oxidative stress (OS) and prostatic enlargement among the aging males through apoptosis deregulation. Our present study aimed to investigate the effect of neferine (NF) in the regulation of oxidative stress and apoptosis in human BPH-1 cells.

METHODS

BPH epithelial cell line BPH-1 was treated with NF for 24 and 48 h. To measure oxidative stress (OS) we investigated MDA, SOD, and GST expression along with Nrf2 and its downstream gene and protein expression. Cell proliferation and apoptosis regulation was assayed with respective methods.

RESULTS

Investigation revealed NF remarkably activate Nrf2 and its downstream proteins HO-1 and NQO1 at 48 h more substantially. Nrf2/Keap1 relative gene and protein expression indicated that NF might trigger Nrf2 upregulation by decreasing Keap1 expression. Both NF concentrations (3 µM and 9 µM) were able to deplete ROS and lipid peroxidation, concurrently, up-regulated SOD and GST. NF reduced cell proliferation significantly along with the regulation of apoptotic proteins Bax, Bcl2, Cyt-C, Caspase 9, and Caspase 3 at the same time (48 h).

CONCLUSION

This study is the first to manifest that NF may potentially regulate BPH by counterbalancing between OS and apoptosis through the activation of Nrf2-ARE pathway.

Isoliensinine Eliminates Afterdepolarizations Through Inhibiting Late Sodium Current and L-Type Calcium Current

Isoliensinine (IL) extracted from lotus seed has a good therapeutic effect on cardiovascular diseases. However, its effect on ion channels of ventricular myocytes is still unclear. We used whole-cell patch-clamp techniques to detect the effects of IL on transmembrane ion currents and action potential (AP) in isolated rabbit left ventricular myocytes. IL inhibited the transient sodium current (I_NaT), late sodium current (I_NaL) enlarged by sea anemone toxin (ATX II) and L-type calcium current (I_CaL) in a concentration-dependent manner without affecting inward rectifier potassium current (I_K1) and delayed rectifier potassium current (I_K). These inhibitory effects are mainly manifested as reduced the AP amplitude (APA) and maximum depolarization velocity (V_max) and shortened the action potential duration (APD), but had no significant effect on the resting membrane potential (RMP). Moreover, IL significantly eliminated ATX II-induced early afterdepolarizations (EADs) and high extracellular calcium-induced delayed afterdepolarizations (DADs). These results revealed that IL effectively eliminated EADs and DADs through inhibiting I_NaL and I_CaL in ventricular myocytes, which indicates it has potential antiarrhythmic action.

Full-length transcriptome analysis of Coptis deltoidea and identification of putative genes involved in benzylisoquinoline alkaloids biosynthesis based on combined sequencing platforms

The study carry out comprehensive transcriptome analysis of C. deltoidea and exploration of BIAs biosynthesis and accumulation based on UHPLC-MS/MS and combined sequencing platforms. Coptis deltoidea is an important medicinal plant with a long history of medicinal use, which is rich in benzylisoquinoline alkaloids (BIAs). In this study, Ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS) and combined sequencing platforms were performed for exploration of BIAs biosynthesis, accumulation and comprehensive transcriptome analysis of C. deltoidea. By metabolism profiling, the accumulation of ten BIAs was analyzed using UHPLC-MS/MS and different contents were observed in different organs. From transcriptome sequencing result, we applied single-molecule real-time (SMRT) sequencing to C. deltoidea and generated a total of 75,438 full-length transcripts. We proposed the candidate biosynthetic pathway of tyrosine, precursor of BIAs, and identified 64 full length-transcripts encoding enzymes putatively involved in BIAs biosynthesis. RNA-Seq data indicated that the majority of genes exhibited relatively high expression level in roots. Transport of BIAs was also important for their accumulation. Here, 9 ABC transporters and 2 MATE transporters highly homologous to known alkaloid transporters related with BIAs transport in roots and rhizomes were identified. These findings based on the combined sequencing platforms provide valuable genetic information for C. deltoidea and the results of transcriptome combined with metabolome analysis can help us better understand BIAs biosynthesis and transport in this medicinal plant. The information will be critical for further characterization of C. deltoidea transcriptome and molecular-assisted breeding for this medicinal plant with scarce resources.

Isolation and characterization of two O-methyltransferases involved in benzylisoquinoline alkaloid biosynthesis in sacred lotus (Nelumbo nucifera)

Benzylisoquinoline alkaloids (BIAs) are a major class of plant metabolites with many pharmacological benefits. Sacred lotus (Nelumbo nucifera) is an ancient aquatic plant of medicinal value because of antiviral and immunomodulatory activities linked to its constituent BIAs. Although more than 30 BIAs belonging to the 1-benzylisoquinoline, aporphine, and bisbenzylisoquinoline structural subclasses and displaying a predominant R-enantiomeric conformation have been isolated from N. nucifera, its BIA biosynthetic genes and enzymes remain unknown. Herein, we report the isolation and biochemical characterization of two O-methyltransferases (OMTs) involved in BIA biosynthesis in sacred lotus. Five homologous genes, designated NnOMT1-5 and encoding polypeptides sharing >40% amino acid sequence identity, were expressed in Escherichia coli Functional characterization of the purified recombinant proteins revealed that NnOMT1 is a regiospecific 1-benzylisoquinoline 6-O-methyltransferase (6OMT) accepting both R- and S-substrates, whereas NnOMT5 is mainly a 7-O-methyltransferase (7OMT), with relatively minor 6OMT activity and a strong stereospecific preference for S-enantiomers. Available aporphines were not accepted as substrates by either enzyme, suggesting that O-methylation precedes BIA formation from 1-benzylisoquinoline intermediates. Km values for NnOMT1 and NnOMT5 were 20 and 13 μm for (R,S)-norcoclaurine and (S)-N-methylcoclaurine, respectively, similar to those for OMTs from other BIA-producing plants. Organ-based correlations of alkaloid content, OMT activity in crude extracts, and OMT gene expression supported physiological roles for NnOMT1 and NnOMT5 in BIA metabolism, occurring primarily in young leaves and embryos of sacred lotus. In summary, our work identifies two OMTs involved in BIA metabolism in the medicinal plant N. nucifera.

Potential Risk of Higenamine Misuse in Sports: Evaluation of Lotus Plumule Extract Products and a Human Study

Since 2017, higenamine has been added to the World Anti-Doping Agency (WADA) prohibited list as a β2-agonist prohibited at all times for sportspersons. According to WADA's report, positive cases of higenamine misuse have been increasing yearly. However, higenamine occurs naturally in the Chinese herb lotus plumule-the green embryo of lotus (Nelumbo nucifera Gaertn) seeds-commercially available as concentrated powder on the Asian market. This study evaluated the major phytochemical components of lotus plumule products using an appropriate extraction method, followed by a human study in which the products were orally administered in multiple doses to investigate the risk of doping violations. Comparing various extraction methods revealed that optimized microwave-assisted extraction exhibited the highest extraction efficiency (extraction time, 26 min; power, 1046 W; and temperature, 120 °C). Subsequently, the alkaloids in lotus plumule products were quantitatively confirmed and compared. Human study participants (n = 6) consumed 0.8 g of lotus plumule (equivalent to 679.6 μg of higenamine) three times daily for three consecutive days. All participants' urinary higenamine concentrations exceeded the WADA reporting cut-off of 10.0 ng/mL. Accordingly, lotus plumule consumption may engender adverse analytical findings regarding higenamine. Athletes should avoid consuming lotus plumule-containing products during in- and out-of-competition periods.

ITRAQ-Based Proteomics Analysis Reveals the Effect of Neoliensinine on KCl-Induced Vascular Smooth Muscle Contraction by Inhibiting Regulatory Light Chain Phosphorylation

Smooth muscle (SM) contraction is one of the important physiological functions of the human body, and SM abnormal contraction will induce many diseases. The phosphorylated regulatory light chains (p-RLC) play a decisive role in SM contraction, and dephosphorylation of p-RLC is an effective way to relax SM. Our previous study showed that the novel benzylisoquinoline alkaloid, neoliensinine (Neo), could relax microvascular SM contracted by KCl hyperpolarization. In this study, mesenteric capillaries isolated from 45 mice were divided into normal tension group (Control), 124 mM KCl induced contraction model group (Model), and KCl and Neo-treatment group (Drug). The dephosphorylation levels of RLC in the three groups were measured. Compared with the model group, the phosphorylation of RLC in the drug group was decreased dramatically as expected, suggesting that the relaxation effect of Neo was caused by downregulating p-RLC of microvessel SM. In order to fully understand its fundamental mechanism, our research focused on the identification of target proteins in mice with KCl-induced contractile mesenteric capillary. Isobaric tags for relative and absolute quantification (ITRAQ) tagging was carried out by nanospray liquid chromatography-tandem mass spectrometry. The results allowed the upregulation of 164 differential abundance proteins (DAPs) among the 3,474 protein abundance disturbances identified from the model/control samples. Further comparison showed that there were 16 DAP convergences associated with vascular SM contraction between the drug/model and the drug/control samples. Among them, two proteins with known function, PLCβ and RhoGEF12, were selected as target proteins of the relaxation effect of Neo. The two selective target DAPs were verified by Western blot at protein level. The results suggested that changes of the two proteins were consistent with that of the iTRAQ results. Our present work reveals that Neo relaxes vascular smooth muscle via inhibition of RLC phosphorylation, and PLCβ and RhoGEF12 may be potential biomarkers for evaluating the effects mediated by Neo.

Benzylisoquinoline Alkaloids Biosynthesis in Sacred Lotus

Sacred lotus (Nelumbo nucifera Gaertn.) is an ancient aquatic plant used throughout Asia for its nutritional and medicinal properties. Benzylisoquinoline alkaloids (BIAs), mostly within the aporphine and bisbenzylisoquinoline structural categories, are among the main bioactive constituents in the plant. The alkaloids of sacred lotus exhibit promising anti-cancer, anti-arrhythmic, anti-HIV, and anti-malarial properties. Despite their pharmacological significance, BIA metabolism in this non-model plant has not been extensively investigated. In this review, we examine the diversity of BIAs in sacred lotus, with an emphasis on the distinctive stereochemistry of alkaloids found in this species. Additionally, we discuss our current understanding of the biosynthetic genes and enzymes involved in the formation of 1-benzylisoquinoline, aporphine, and bisbenzylisoquinoline alkaloids in the plant. We conclude that a comprehensive functional characterization of alkaloid biosynthetic enzymes using both in vitro and in vivo methods is required to advance our limited knowledge of BIA metabolism in the sacred lotus.

Characterization of polysaccharides and their antioxidant properties from Plumula nelumbinis

Two novel polysaccharides, Plumula nelumbinis (P. nelumbinis) polysaccharide I (LNP I) and P. nelumbinis polysaccharide II (LNP II), were extracted and purified from P. nelumbinis, and a sulfated polysaccharide, P. nelumbinis polysaccharide III (LNP III), with a substitution degree of 0.62 was prepared from LNPI. The structures of the LNPs were preliminarily characterized using high performance size exclusion chromatography (HPSEC), gas chromatography-mass spectrometry (GC–MS), Fourier transformed infrared spectrometry (FT-IR), and nuclear magnetic resonance (NMR) spectrometry. In addition, evaluation of the antioxidant activity of the LNPs showed that they could significantly increase the proliferation of RAW264.7 macrophages (P < 0.05) and improve the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) based on cell model of H₂O_2-induced oxidative damage. This suggested that these LNPs may be used as potential antioxidants.

[Diversity of Secondary Metabolites from Some Medicinal Plants and Cultivated Lichen Mycobionts]

 Studies on the structural determination, biosynthesis, and biological activities of secondary metabolites from natural sources are significant in the field of natural products chemistry. This review focuses on diverse secondary metabolites isolated from medicinal plants and cultivated mycobionts of lichens in our laboratory. Monoterpene-tetrahydroisoquinoline glycosides and alkaloids isolated from Cephaelis acuminata and Alangium lamarckii gave important information on the biosynthesis of ipecac alkaloids. A variety of glycosides linked with a secologanin unit and indole alkaloids were obtained from medicinal plants belonging to the families of Rubiaceae, Apocynaceae, and Loganiaceae. Plant species of the four genera Fraxinus, Syringa, Jasminum, and Ligustrum of the family Oleaceae were chemically investigated to provide several types of secoiridoid and iridoid glucosides. The biosynthetic pathway leading from protopine to benzophenanthridine alkaloids in suspension cell cultures of Eschscholtzia californica was elucidated. The structures and biological activities of the bisbenzylisoquinoline alkaloids of Stephania cepharantha and Nelumbo nucifera were also investigated. In addition, the mycobionts of lichens were cultivated to afford various types of metabolites that differ from the lichen substances of intact lichens but are structurally similar to fungal metabolites. The biosynthetic origins of some metabolites were also studied. These findings suggest that cultures of lichen mycobionts could be sources of new bioactive compounds and good systems for investigating secondary metabolism in lichens.

Digital Gene Expression Analysis Provides Insight into the Transcript Profile of the Genes Involved in Aporphine Alkaloid Biosynthesis in Lotus (Nelumbo nucifera)

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.

Current Advances in the Metabolomics Study on Lotus Seeds

Lotus (Nelumbo nucifera), which is distributed widely throughout Asia, Australia and North America, is an aquatic perennial that has been cultivated for over 2,000 years. It is very stimulating that almost all parts of lotus have been consumed as vegetable as well as food, especially the seeds. Except for the nutritive values of lotus, there has been increasing interest in its potential as functional food due to its rich secondary metabolites, such as flavonoids and alkaloids. Not only have these metabolites greatly contributed to the biological process of lotus seeds, but also have been reported to possess multiple health-promoting effects, including antioxidant, anti-amnesic, anti-inflammatory, and anti-tumor activities. Thus, comprehensive metabolomic profiling of these metabolites is of key importance to help understand their biological activities, and other chemical biology features. In this context, this review will provide an update on the current technological platforms, and workflow associated with metabolomic studies on lotus seeds, as well as insights into the application of metabolomics for the improvement of food safety and quality, assisting breeding, and promotion of the study of metabolism and pharmacokinetics of lotus seeds; meanwhile it will also help explore new perspectives and outline future challenges in this fast-growing research subject.

Analysis of Isoquinoline Alkaloid Composition and Wound-Induced Variation in Nelumbo Using HPLC-MS/MS

Alkaloids are the most relevant bioactive components in lotus, a traditional herb in Asia, but little is known about their qualitative and quantitative distributions. Here, we report on the alkaloid composition in various lotus organs. Lotus laminae and embryos are rich in isoquinoline alkaloids, whereas petioles and rhizomes contain trace amounts of alkaloids. Wide variation of alkaloid accumulation in lamina and embryo was observed among screened genotypes. In laminae, alkaloid accumulation increases during early developmental stages, reaches the highest level at full size stage, and then decreases slightly during senescence. Vegetative and embryogenic tissues accumulate mainly aporphine-type and bisbenzylisoquinoline-type alkaloids, respectively. Bisbenzylisoquinoline-type alkaloids may be synthesized mainly in lamina and then transported into embryo via latex through phloem translocation. In addition, mechanical wounding was shown to induce significant accumulation of specific alkaloids in lotus leaves.

In vitro opioid receptor affinity and in vivo behavioral studies of Nelumbo nucifera flower

ETHNOPHARMACOLOGICAL RELEVANCE

Nelumbo nucifera Geartn., known as sacred lotus, has been used traditionally in South East Asia as a traditional medicine for various CNS disorders including stress, fever, depression, insomnia, and cognitive conditions.

AIM OF THE STUDY

To investigate the in vitro cannabinoid and opioid receptor binding affinities, and in vivo behavioral actions of Nelumbo flower extracts and to isolate the potential compounds to treat CNS associated disorders.

MATERIALS AND METHODS

The white and pink flowers of N. nucifera were extracted with 95% EtOH, followed by acid-base partitioning using CHCl3 to give acidic and basic partitions. These partitions were subjected to Centrifugal Preparative TLC (CPTLC) to yield benzyltetrahydroisoquinoline (BTIQ) alkaloids and long chain fatty acids, identified by physical and spectroscopic methods. In addition, EtOH extracts and partitions were analyzed for chemical markers by UHPLC/MS and GC/MS. In vitro neuropharmacological effects were evaluated by cannabinoid (CB1 and CB2) and opioid [delta (δ), kappa (ĸ), and mu (µ)] competitive radioligand binding and GTPγS functional assays. The in vivo behavioral effect was studied through the use of the mouse tetrad assay at 10, 30, 75 and 100mg/kg/ip doses that revealed the effect on locomotion, catalepsy, body temperature, and nociception of acidic and basic CHCl3 partitions, fractions, and compounds.

RESULTS

Three aporphines, nuciferine (1), N-nor-nuciferine (2), asimilobine (3), and five BTIQs, armepavine (4), O-methylcoclaurine (5), N-methylcoclaurine (6), coclaurine (7), neferine (10), and a mixture of linoleic and palmitic acids (LA and PA), were identified and evaluated for cannabinoid and opioid receptor displacement activities. Compounds 5-7 showed binding affinities for the ĸ opioid receptor with equilibrium dissociation constant (Ki) values of 3.5 ± 0.3, 0.9 ± 0.1, 2.2 ± 0.2 μM, respectively. Compound 10 displayed affinities for δ-and µ- opioid receptors with Ki values of 0.7 ± 0.1 and 1.8 ± 0.2 μM, respectively, and was determined to be a weak δ agonist by GTPγS functional assay. The mixture of LA and PA (1:1) showed an affinity for δ opioid receptor with a Ki value of 9.2 ± 1.1 μM. The acidic and basic CHCl3 partitions, compounds 1 and 7, and 5-7 mixture were subjected to the tetrad assay, of which the acidic partition displayed decreased locomotion and increased catalepsy, antinociception, and hypothermia in animal at doses of 75-100 mg/kg/ip, and also showed clonic-tonic seizures upon touch at 100mg/kg.

CONCLUSION

Bioassay-guided isolation revealed compounds 5-7, 10, and the mixture of LA and PA displayed various degrees of opioid receptor radioligand displacement affinities. The in vivo tetrad assay of acidic CHCl3 partition, enriched with aporphines 1 and 2, displayed actions on all four points of behavioral parameters. It can be concluded that the in vivo mild canabimimetic-type effect observed for the CHCl3 partition is likely mediated through other CNS mechanisms since the extracts, partitions, and isolated compounds had no affinity for the in vitro CB1 and CB2 receptors. This work, along with traditional use and the reported bioactivities of the BTIQ alkaloids, suggested further studies on N. nucifera are needed to understand the roles that the extracts and/or individual compounds might contribute to the behavioral effects.

Serotonergic mechanisms are involved in antidepressant-like effects of bisbenzylisoquinolines liensinine and its analogs isolated from the embryo of Nelumbo nucifera Gaertner seeds in mice

Objectives

We attempted to ascertain if bisbenzylisoquinoline alkaloids, liensinine and isoliensinine from Nelumbo nucifera Gaertner have antidepressant-like effects and compare the effects with those previously obtained by their analogue neferine.

Methods

Using mice, the forced swimming test (FST) was carried out after treatment with liensinine, isoliensinine and neferine.

Key findings

Liensinine and isoliensinine elicited antidepressant-like effects in mice after the FST. Anti-immobility effects of liensinine and isoliensinine were antagonized by the 5-hydroxytryptamine1A (5-HT1A) receptor antagonist WAY 100635, but not by the α1-adrenoceptor antagonist prazosin. The anti-immobility effects of liensinine, isoliensinine and neferine were blocked by pretreatment with p-chlorophenylalanine (PCPA), which depletes serotonin (5-HT).

Conclusions

These data suggest that liensinine and isoliensinine from Nelumbo nucifera Gaertner have antidepressant-like effects and that antidepressant-like effects of liensinine and its analogues are closely related to serotonergic mechanisms.

Human Ether-à-go-go Related Gene (hERG) Channel Blocking Aporphine Alkaloids from Lotus Leaves and Their Quantitative Analysis in Dietary Weight Loss Supplements

Blockage of the human ether-à-go-go related gene (hERG) channel can result in life-threatening ventricular tachyarrhythmia. In an in vitro screening of herbal materials for hERG blockers using an automated two-microelectrode voltage clamp assay on Xenopus oocytes, an alkaloid fraction of Nelumbo nucifera Gaertn. (lotus) leaves induced ∼50% of hERG current inhibition at 100 μg/mL. Chromatographic separation resulted in the isolation and identification of (-)-asimilobine, 1, nuciferine, 2, O-nornuciferine, 3, N-nornuciferine, 4, and liensinine, 5. In agreement with in silico predicted ligand-target interactions, 2, 3, and 4 revealed distinct in vitro hERG blockages measured in HEK293 cells with IC50 values of 2.89, 7.91, and 9.75 μM, respectively. Because lotus leaf dietary weight loss supplements are becoming increasingly popular, the identified hERG-blocking alkaloids were quantitated in five commercially available products. Results showed pronounced differences in the content of hERG-blocking alkaloids ranging up to 992 μg (2) in the daily recommended dose.

Simultaneous determination of liensinine, isoliensinine and neferine in rat plasma by UPLC-MS/MS and application of the technique to pharmacokinetic studies

ETHNOPHARMACOLOGICAL RELEVANCE

The in vivo effects of traditional herbal medicines are generally mediated by multiple bioactive components. The main constituents of Lotus Plumule are alkaloids such as liensinine, isoliensinine and neferine. In this study, a simple, sensitive, and robust analytical method based on ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) has been developed for the determination of the three alkaloids in rat plasma using carbamazepine as internal standard (IS).

MATERIALS AND METHODS

After precipitation of the proteins with acetonitrile, chromatography was performed on an Acquity UPLC BEH C18 column (2.1mm×50mm, 1.7μm particle size) using a gradient elution with 0.1% formic acid in water and acetonitrile. Mass spectrometry involved positive electrospray ionization and multiple reaction monitoring (MRM) of the transitions at m/z 611.7→206.2 for liensinine, 611.3→192.2 for isoliensinine, 625.2→206.1 for neferine and m/z 237.1→194.2 for IS.

RESULTS

The method was linear over the concentration range 5-1000ng/mL with a lower limit of quantifof 5ng/mL for each alkaloid. Inter- and intra-day precision (RSD%) were all within 11.4% and the accuracy (RE%) were equal or lower than 10.4%. Recoveries were more than 75.3% and matrix effects were not significant. Stability studies showed that the three alkaloids were stable under a variety of storage conditions.

CONCLUSION

The method was successfully applied to a pharmacokinetic study involving intravenous administration of liensinine, isoliensinine and neferine to rats.

Cognitive Enhancing and Neuroprotective Effect of the Embryo of the Nelumbo nucifera Seed

The aim of the present study was to evaluate the effect of ENS on cognitive impairment induced by scopolamine and its potential neuroprotective effect against glutamate-induced cytotoxicity in HT22 cell and to investigate the underlying mechanisms. ENS (3, 10, 30, and 100 mg/kg), scopolamine (1 mg/kg), and donepezil (1 mg/kg) were administered to mice during a test period. Scopolamine impaired memory and learning in a water maze test and a passive avoidance test. The neuroprotective effect of ENS (10 and 100 μg/mL) was investigated on glutamate-induced cell death in HT22 cells by MTT assay. We investigated acetylcholinesterase inhibition in hippocampus and antioxidant activity, ROS levels, and Ca²⁺ influx in HT22 cells to elucidate the potential mechanisms of ENS. We found that ENS significantly ameliorated scopolamine-induced memory impairment and inhibited AChE activity in hippocampus. In vitro, ENS showed potent neuroprotective effects against glutamate-induced neurotoxicity in the HT22 cell. In addition, ENS induced a decrease in ROS production and intercellular Ca²⁺ accumulation and showed DPPH radical and H₂O₂ scavenging activity. In conclusion, ENS showed both a memory improving effect and a neuroprotective effect. Our results indicate that ENS may be of use in the treatment and prevention of neurodegenerative disorders.

Identification and comparison of anti-inflammatory ingredients from different organs of Lotus nelumbo by UPLC/Q-TOF and PCA coupled with a NF-κB reporter gene assay

Lotus nelumbo (LN) (Nelumbo nucifera Gaertn.) is an aquatic crop that is widely distributed throughout Asia and India, and various parts of this plant are edible and medicinal. It is noteworthy that different organs of this plant are used in traditional herbal medicine or folk recipes to cure different diseases and to relieve their corresponding symptoms. The compounds that are contained in each organ, which are named based on their chemical compositions, have led to their respective usages. In this work, a strategy was used to identify the difference ingredients and screen for Nuclear-factor-kappaB (NF-κB) inhibitors with anti-inflammatory ability in LN. Seventeen main difference ingredients were compared and identified from 64 samples of 4 different organs by ultra-performance liquid chromatography that was coupled with quadrupole/time of flight mass spectrometry (UPLC/Q-TOF-MS) with principal component analysis (PCA). A luciferase reporter assay system combined with the UPLC/Q-TOF-MS information was applied to screen biologically active substances. Ten NF-κB inhibitors from Lotus plumule (LP) extracts, most of which were isoquinoline alkaloids or flavone C-glycosides, were screened. Heat map results showed that eight of these compounds were abundant in the LP. In conclusion, the LP extracts were considered to have the best anti-inflammatory ability of the four LN organs, and the chemical material basis (CMB) of this biological activity was successfully validated by multivariate statistical analysis and biological research methods.