Bioactive alkaloid extracts from Narcissus broussonetii: mass spectral studies

Influence of Sucrose and Activated Charcoal on Phytochemistry and Vegetative Growth in Zephyranthes irwiniana (Ravenna) Nic. García (Amaryllidaceae)

Zephyranthes irwiniana (Ravenna) Nic. García is an endemic, red list threatened species from the Brazilian savanna (Cerrado) with pharmacological potential to treat the symptoms of Alzheimer's Disease (AD). This work analyzed the vegetative growth and phytochemistry of its potential compounds, in response to variations in sucrose concentration and activated carbon (AC). Seeds were germinated in vitro and in the greenhouse. The in vitro bulbs were separated in six treatments with different sucrose concentrations (30, 45 and 60 gL-1) and/or AC (1 gL-1). Biomass increases in individuals grown in the greenhouse were higher than those cultivated in vitro. Sucrose concentration significantly increased biomass and root number. AC had a positive influence on leaf and root size, and a negative influence on root number. GC-MS analyses indicated great variation in the abundance of α-terpenyl-acetate, ethyl linoleate, clionasterol and lycorine between treatments, with maximum concentrations of 53.06%, 38.68, 14.34% and 2.57%, respectively. Histolocalization tests indicated the presence of alkaloids in the leaf chlorenchyma and bulb cataphylls. Finally, the present study provided new evidence that the constitution of the culture medium directly influences the vegetative growth and phytochemistry of this species, providing a good medium condition for propagating the species under threat.

Alkaloid Composition and Biological Activities of the Amaryllidaceae Species Ismene amancaes (Ker Gawl.) Herb

Natural products have always played a significant role in the search for new drugs. One of the most relevant alkaloid-containing plant groups is the Amaryllidaceae family, a source of exclusive structures with a wide variety of pharmacological activities. The aim of this work was to determine the alkaloid composition and biological potential of an extract from the bulbs of an endemic Peruvian Amaryllidaceae species Ismene amancaes (Ker Gawl.) Herb. The alkaloid profiling was carried out by GC-MS, which revealed the presence of 13 compounds, 2 of them unidentified. The plant extract was found to contain high amounts of lycoramine, a galanthamine-type alkaloid. The extract also presented low inhibitory potential against the enzymes AChE and BuChE, with IC50 values of 14.6 ± 0.6 and 37.6 ± 1.4 μg·mL−1, respectively, and good to moderate inhibitory activity against the protozoan Plasmodium falciparum strain FCR-3 (chloroquine-resistant), with IC50 values of 3.78 ± 0.3 μg·mL−1. This is the first report of the alkaloid profile of a plant of the Ismene genus, which could be an interesting source of bioactive compounds.

Anti-Trypanosoma cruzi activity of alkaloids isolated from Habranthus brachyandrus (Amaryllidaceae) from Argentina

BACKGROUND

Chagas disease, caused by the parasite Trypanosoma cruzi, affects over six million people worldwide, mainly in Latin American countries. Currently available drugs have variable efficacy in the chronic phase and significant side effects, so there is an urgent need for safer chemotherapeutic treatments. Natural products provide privileged structures that could serve as templates for the synthesis of new drugs. Among them, Amaryllidaceae plants have proved to be a potential natural source of therapeutical agents due to their rich diversity in alkaloids.

PURPOSE

To identify alkaloids with anti-T. cruzi activity from Habranthus brachyandrus (Baker) Sealy (Amaryllidaceae, subfamily Amaryllidoideae) collected in Argentina.

METHODS

An H. brachyandrus alkaloid extract was tested against T. cruzi, and its cytotoxicity profile was evaluated against two mammalian cell lines to ascertain its selectivity against the parasite and potential liver toxicity. It was also assessed by a stage-specific anti-amastigote assay and analysed by GC/MS to determine its alkaloid profile. The isolated alkaloids were also tested using the aforementioned assays.

RESULTS

The extract showed high and specific activity against T. cruzi. The alkaloids lycoramine, galanthindole, 8-O-demethylmaritidine, 8-O-demethylhomolycorine, nerinine, trisphaeridine, deoxytazettine, and tazettamide were identified by means of GC-MS. In addition, hippeastidine (also named aulicine), tazzetine, ismine, and 3-epimacronine were isolated. The alkaloid ismine was specifically active against the parasite and had low toxicity against HepG2 cells, but did not show anti-amastigote activity.

CONCLUSION

The extract had specific anti-T. cruzi activity and the isolated alkaloid ismine was partially responsible of it. These results encourage further exploration of H. brachyandrus alkaloids in search of novel starting points for Chagas disease drug development.

Combating Bovine Mastitis in the Dairy Sector in an Era of Antimicrobial Resistance: Ethno-veterinary Medicinal Option as a Viable Alternative Approach

Bovine mastitis (BM) is the traditional infectious condition in reared cattle which may result in serious repercussions ranging from animal welfare to economic issues. Owing to the high costs associated with preventative practices and therapeutic measures, lower milk output, and early culling, bovine mastitis is accountable for most of the financial losses suffered in cattle farming. Streptococcus agalactiae, Staphylococcus aureus, Streptococcus dysgalactiae and coliform bacteria are the predominant pathogens for bovine mastitis. In addition, the occurrence of BM has been linked to lactation stage and poor management, in the latter case, the poor stabling conditions around udder hygiene. BM occurs throughout the world, with varying rates of Streptococcus agalactiae infection in different regions. Despite the modern techniques, such as the appropriate milking practices that are applied, lower levels of pathogen vulnerability may help to prevent the development of the disease, BM treatment is primarily reliant on antibiotics for both prophylactic and therapeutic purposes. Nevertheless, as a result of the proliferation of bacterial agents to withstand the antibiotic effects, these therapies have frequently proven ineffectual, resulting in persistent BM. Consequently, alternative medicines for the management of udder inflammation have been researched, notably natural compounds derived from plants. This review focuses on BM in terms of its risk factors, pathogenesis, management, the molecular identification of causative agents, as well as the application of ethno-veterinary medicine as an alternative therapy.

Alkaloid Profiling, Anti-Enzymatic and Antiproliferative Activity of The Endemic Chilean Amaryllidaceae Phycella cyrtanthoides

This research aims to identify the alkaloid profile and to evaluate the enzyme inhibitory potential and antiproliferative effects of the Amaryllidaceae plant Phycella cyrtanthoides. The alkaloid extracts from bulbs and leaves were analyzed using ultrahigh performance liquid chromatography orbitrap mass spectrometry (UHPLC-Orbitrap-MS) analysis. A total of 70 alkaloids were detected in the P. cyrtanthoides’ extracts. The enzyme inhibition potential against cholinesterases (AChE: acetylcholinesterase, and BChE butyrylcholinesterase) and tyrosinase were studied. Bulbs displayed the best IC₅₀ values against AChE (4.29 ± 0.03 µg/mL) and BChE (18.32 ± 0.03 µg/mL). These results were consistent with docking experiments with selected major compounds in the active sites of enzymes, while no activity was observed against tyrosinase enzyme. Antiproliferative effects were investigated against human cervical (HeLa), lung (A549, SW1573), colon (WiDr), and breast (HBL-100, T-47D) tumor cell lines. Bulbs and leaves were active in all cell lines (GI₅₀ < 2.5 µg/mL). These findings suggest that the endemic Chilean plant P. cyrtanthoides contains diverse types of bioactive alkaloids with antiproliferative activities and inhibitory effects with potential therapeutic applications for neurodegenerative diseases

Transcriptome analysis of Leucojum aestivum and identification of genes involved in norbelladine biosynthesis

Transcriptome analysis of Leucojum aestivum led to the identification of 50 key genes associated with Amaryllidaceae alkaloid biosynthesis including norbelladine synthase which localized in the cytosol and catalyzed norbelladine formation. The Amaryllidaceae alkaloids (AAs) are a large group of plant specialized metabolites, which are known for their biological activities. Although the general chemical reactions in the AA biosynthetic pathway have been proposed, the genes and enzymes of the pathway remain largely unstudied. All AAs are synthesized from a common precursor, norbelladine, by the condensation of tyramine and 3,4-dihydroxybenzaldehyde. The enzyme norbelladine synthase (NBS) which catalyzes the condensation reaction has only been characterized at a molecular level from one species, and the subcellular localizations have not been explored. Hence, the intracellular compartments wherein the AAs are biosynthesized remain unknown. In this study, a first comprehensive transcriptomic analysis of summer snowflake (Leucojum aestivum) was done to identify key genes associated with AA biosynthesis. Fifty orthologous genes were identified and deposited into GenBank. In addition, we identified and further characterized NBS from the transcriptome of L. aestivum and previously reported Narcissus papyraceus. Phylogenetic analysis showed that LaNBS, NpNBS1 and NpNBS2 shared high amino acid identity. The heterologous expression of LaNBS produced a recombinant protein with NBS activity. Bioinformatic prediction and C-terminal GFP tagging in transiently transformed Nicotiana benthamiana showed that LaNBS, NpNBS1 and NpNBS2 were likely localized to the cytosol which suggests that the AA biosynthesis starts in the cytosol. This study provides an Amaryllidaceae transcriptome that will be very helpful to identify genes for characterization studies in AA metabolism in planta or using heterologous systems. In addition, our study will facilitate the bioengineering of AA biosynthetic pathway in plants or in microorganisms.

Structural Diversity and Biological Potential of Alkaloids from the Genus Hippeastrum, Amaryllidaceae: an Update

The subfamily Amaryllidoideae, Amaryllidaceae, presents an exclusive group of structures known as Amaryllidaceae alkaloids, which have a broad spectrum of biological activities. These plants are classified into 59 genera, including Hippeastrum Herb., which comprises approximately 60 species distributed mainly in South America, being widely used as ornamental plants due to the beauty of its flowers. This review presents an update about the alkaloid profiling of Hippeastrum extracts published between 2012 and 2021, as well as an approach to the biological potential of these compounds.

GRAPHICAL ABSTRACT

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s43450-021-00211-z.

GC-MS analysis of Amaryllidaceae and Sceletium-type alkaloids in bioactive fractions from Narcissus cv. Hawera

RATIONALE

Narcissus cv. Hawera has been found to biosynthesize some Sceletium-type alkaloids with antidepressant and anxiolytic activities. This ornamental plant has been poorly studied as a source of bioactive alkaloids including some contraversive reports on in vitro and intact plants. In this study, a detailed GC-MS characterization of its alkaloid fractions is presented.

METHODS

GC-MS was used for the identification of compounds in the alkaloid fractions. Both underivatized and silylated samples were analyzed simultaneously. Elevated plus maze and tail suspension tests were used to assay the anxiolytic and antidepressant activities. Ellman's and MTT-dye reduction assays were used to evaluate the acetylcholinesterase (AChE) inhibitory and cytotoxicity activities, respectively.

RESULTS

Of the 29 alkaloids, 13 of Sceletium-type were detected. Two new alkaloids were identified as 2-oxo-mesembrine and 2-oxo-epi-mesembrenol. Lycorine was found as a major compound (43.5%) in the crude silylated methanol extract. After the elimination of lycorine by pre-crystallization, the major alkaloids were 40.8% 6-epi-mesembranol, 16.2% 6-epi-mesembrenol, and 13.8% sanguinine. This fraction showed anxiolytic and antidepressant-like activities as well as potent AChE inhibitory and antineoplastic activities.

CONCLUSIONS

Silylation of the alkaloid fractions from Narcissus cv. Hawera provides better separation, structural information, and improved sensitivity for compounds with two and more hydroxyl groups. The lycorine-free alkaloid fraction shows a great potential for further pharmacological studies.

Alkaloids Analysis of Habranthus cardenasianus (Amaryllidaceae), Anti-Cholinesterase Activity and Biomass Production by Propagation Strategies

Plants in the Amaryllidaceae family synthesize a diversity of bioactive alkaloids. Some of these plant species are not abundant and have a low natural multiplication rate. The aims of this work were the alkaloids analysis of a Habranthus cardenasianus bulbs extract, the evaluation of its inhibitory activity against cholinesterases, and to test several propagation strategies for biomass production. Eleven compounds were characterized by GC-MS in the alkaloid extract, which showed a relatively high proportion of tazettine. The known alkaloids tazettine, haemanthamine, and the epimer mixture haemanthidine/6-epi-haemanthidine were isolated and identified by spectroscopic methods. Inhibitory cholinesterases activity was not detected. Three forms of propagation were performed: bulb propagation from seed, cut-induced bulb division, and micropropagated bulbs. Finally, different imbibition and post-collection times were evaluated in seed germination assays. The best propagation method was cut-induced bulb division with longitudinal cuts into quarters (T1) while the best conditions for seed germination were 0-day of post-collection and two days of imbibition. The alkaloids analyses of the H. cardenasianus bulbs showed that they are a source of anti-tumoral alkaloids, especially pretazettine (tazettine) and T1 is a sustainable strategy for its propagation and domestication to produce bioactive alkaloids.

Amaryllidaceae alkaloids with anti-Trypanosoma cruzi activity

Background

Chagas disease, caused by the protozoan Trypanosoma cruzi, is a neglected disease that affects ~7 million people worldwide. Development of new drugs to treat the infection remains a priority since those currently available have frequent side effects and limited efficacy at the chronic stage. Natural products provide a pool of diversity structures to lead the chemical synthesis of novel molecules for this purpose. Herein we analyzed the anti-T. cruzi activity of nine alkaloids derived from plants of the family Amaryllidaceae.

Methods

The activity of each alkaloid was assessed by means of an anti-T. cruzi phenotypic assay. We further evaluated the compounds that inhibited parasite growth on two distinct cytotoxicity assays to discard those that were toxic to host cells and assure parasite selectivity.

Results

We identified a single compound (hippeastrine) that was selectively active against the parasite yielding selectivity indexes of 12.7 and 35.2 against Vero and HepG2 cells, respectively. Moreover, it showed specific activity against the amastigote stage (IC₅₀ = 3.31 μM).

Conclusions

Results reported here suggest that natural products are an interesting source of new compounds for the development of drugs against Chagas disease.

GC/MS Analysis of Alkaloids in Galanthus fosteri Baker and Determination of Its Anticholinesterase Activity

Objectives

Amaryllidaceae alkaloids are well known for their wide range of pharmacological activities. Galanthamine, an Amaryllidaceae alkaloid, is an effective, selective, reversible, and competitive cholinesterase inhibitor marketed under different commercial names in several countries for the treatment of Alzheimer's disease. The aim of this work was to study the alkaloid profiles of the aerial parts and bulbs of both flowering and fruiting periods of Galanthus fosteri Baker (Amaryllidaceae), as well as analyzing their inhibitory activities on both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) for the first time.

Materials and Methods

The alkaloid profiles of the four samples were determined by means of gas chromatography-mass spectrometry, and AChE and BuChE inhibition assays were performed by the modified Ellman method.

Results

Totally, 22 compounds with mass spectral characteristics of Amaryllidaceae alkaloids were detected in the extracts. Significant AChE and BuChE inhibitory activities were observed in the tested samples (IC₅₀ between 0.189 and 91.23 μg/mL).

Conclusion

This study shows that G. fosteri, collected from Akdağ, Amasya (Turkey), is a potential source of diverse chemical structures of Amaryllidaceae alkaloids with cholinesterase inhibitory properties.

Chemodiversity, chemotaxonomy and chemoecology of Amaryllidaceae alkaloids

The Amaryllidaceae alkaloids are a distinctive chemotaxonomic feature of the subfamily Amaryllidoideae of the family Amaryllidaceae, which consists of 59 genera and >800 species distributed primarily in tropical and subtropical areas. Since the first isolation, ca. 140 ago, >600 structurally diverse Amaryllidaceae alkaloids have been reported from ca. 350 species (44% of all species in the subfamily). A few have been found in other plant families, but the majority are unique to the Amaryllidoideae. These alkaloids have attracted considerable research interest due to their wide range of biological and pharmacological activities, which have been extensively reviewed. In this chapter we provide a review of the 636 structures of isolated or tentatively identified alkaloids from plants of the Amaryllidoideae and their classification into 42 skeleton types, as well as a discussion on their distribution, and chemotaxonomical and chemoecological aspects.

Antiplasmodial Studies Within the Plant Family Amaryllidaceae

Plants have long served as a first line of defense response to malaria. They have also spawned several classes of antimalarial drugs such as quinine and artemisinin. However, most if not all of these drugs have succumbed to multidrug resistance, thus reigniting interest in the identification of novel chemotherapies against this parasitic disease. The starting point for many of such endeavors lies with the plants themselves whose extracts have served as herbal remedies, which originate from traditional medicine (TM). Several species of the Amaryllidaceae have been shown to have such functions in TM. This survey examines those plants of the family, which have hitherto been examined for antiplasmodial effects against the malarial parasite Plasmodium falciparum. Also considered are the alkaloid constituents of these plants, which have demonstrated activities against various strains of the pathogen. Particular emphasis is made on those plants which both demonstrate such activity as well as have a place in traditional therapies for malaria.

Antiprotozoal alkaloid principles of the plant family Amaryllidaceae

Protozoan-borne diseases are prominent amongst diseases caused by parasites. Given their alarming morbidity and mortality statistics, there is ever growing interest in new therapies against these diseases. Whilst synthetic drugs such as benznidazole and melarsoprol have had a profound influence on the clinical setup, there has been significant interest in the phytochemical platform to also deliver such drug candidates. The plant family Amaryllidaceae is recognizable for its isoquinoline alkaloids, which exhibit attractive molecular architectures and interesting biological properties. This survey focuses on the antiprotozoal activities of 73 of such substances described in 18 different species of the Amaryllidaceae. Of these, 2-O-acetyllycorine was identified as the most potent (IC₅₀ 0.15 μg/mL against Trypansoma brucei brucei). Also considered are structure-activity relationships which have served to modulate activities, as well as the plausible mechanisms that underpin these effects and afford insight to the Amaryllidaceae alkaloid antiprotozoal pharmacophore.

Developmental Regulation of the Expression of Amaryllidaceae Alkaloid Biosynthetic Genes in Narcissus papyraceus

Amaryllidaceae alkaloids (AAs) have multiple biological effects, which are of interest to the pharmaceutical industry. To unleash the potential of Amaryllidaceae plants as pharmaceutical crops and as sources of AAs, a thorough understanding of the AA biosynthetic pathway is needed. However, only few enzymes in the pathway are known. Here, we report the transcriptome of AA-producing paperwhites (Narcissus papyraceus Ker Gawl). We present a list of 21 genes putatively encoding enzymes involved in AA biosynthesis. Next, a cDNA library was created from 24 different samples of different parts at various developmental stages of N. papyraceus. The expression of AA biosynthetic genes was analyzed in each sample using RT-qPCR. In addition, the alkaloid content of each sample was analyzed by HPLC. Leaves and flowers were found to have the highest abundance of heterocyclic compounds, whereas the bulb, the lowest. Lycorine was also the predominant AA. The gene expression results were compared with the heterocyclic compound profiles for each sample. In some samples, a positive correlation was observed between the gene expression levels and the amount of compounds accumulated. However, due to a probable transport of enzymes and alkaloids in the plant, a negative correlation was also observed, particularly at stage 2.

Screening of Amaryllidaceae alkaloids in bulbs and tissue cultures of Narcissus papyraceus and four varieties of N. tazetta

Narcissus spp. are an economically important crop for medicines in relation with the alkaloids production, mainly galanthamine, an acetylcholinesterase inhibitor used for the treatment of Alzheimer's disease. In this article an extensively study of the phytochemistry of both bulbs of different species and varieties of Narcissus grown in Iran and in vitro culture of these plants was investigated. In particular, the Amaryllidaceae alkaloid profile and the galanthamine and lycorine contents in wild bulbs of Narcissus papyraceus (G5) and four varieties of Narcissus tazetta (N. tazetta var. Shahla (G4), N. tazetta var. Shastpar (G1), N. tazetta var. Meskin (G2), N. tazetta var. Panjehgorbei (G3)), growing in Iran are reported. The alkaloid profiles were investigated by GC-MS and LC-MS and the quantitative analysis was performed using GC-MS. In total, thirty alkaloids were identified among them nine alkaloids were observed with the both methods of analysis. The variety Meskin of N. tazetta (G2), showed the highest diversity of alkaloids and the highest content in galanthamine. On this last species (G2) and on N. tazetta var. Shahla (G4), the effects of auxins 2,4-dichlorophenoxyacetic acid (2,4-D), 4-amino-3,5,6-trichloropicolinic acid (Picloram) and naphthalene acetic acid (NAA) at concentrations of 25 and 50 μM were studied on the induction of callus and its capacity to induce organogenesis and alkaloid diversity. All auxins, at the concentrations of 25 and 50 μM, produced calli. Bulblets and roots were formed on calli grown only in the presence of 25 or 50 μM NAA. GC-MS analyses showed the presence of galanthamine and lycorine in calli, roots and bulblets, with all auxins whatever the concentration used while demethylmaritidine and tazettine were found in differentiated tissue cultures cultivated on the medium containing NAA (25 or 50 μM) or in calli initiated with Picloram (50 μM). Precursor 4'-O-methylnorbelladine (MN) of Amaryllidaceae alkaloids feeding was found to significantly improve the accumulation of both galanthamine (82 μg/g DW) and lycorine (1800 μg/g DW) in bulblets of N. tazetta var. Meskin (G2).

The Amaryllidaceae as a source of antiplasmodial crinane alkaloid constituents

Malaria is prevalent in tropical and subtropical regions of the globe. With over 200 million cases reported annually, particularly in sub-Saharan Africa, it is an unnecessary burden to already overworked and ailing healthcare structures. Traditional medicine (TM) remains vibrant in most of these regions wherein plants often serve as the first line of defense against malaria. Given this fact as well as the successes elsewhere of therapies such as Artemisia annua emanating from evidence-based TM, interest in plants as a source of new antimalarial drugs has been rejuvenated. The bulbous plant family Amaryllidaceae is recognized for its structurally-diverse alkaloid constituents which exhibit interesting biological properties. This review focuses on the in vitro activities demonstrated by its crinane alkaloids against various strains of the malaria-causing parasite Plasmodium falciparum. The survey embraces the twelve genera of the Amaryllidaceae whose nineteen representative species have been examined for antiplasmodial crinane alkaloid principles. A total of seventy-two compounds were screened against nine strains of P. falciparum, with the α-crinanes reflecting better overall activities than their corresponding β-crinane subgroup congeners. In terms of potency, an ED₅₀ of 0.14 μg/mL (for augustine in the D-6 strain) and IC₅₀ of 0.35 μg/mL (for haemanthidine in the K1 strain) were the lowest activity indices observed. Structure-activity relationship studies afforded useful insight on the antiplasmodial pharmacophore and the features supporting its efficacy. Overall, crinane alkaloids have provided a useful platform for the study of antiplasmodial effects, not only in terms of potency but also in terms of structural diversity.

Cholinesterase Inhibition Activity, Alkaloid Profiling and Molecular Docking of Chilean Rhodophiala (Amaryllidaceae)

Amaryllidaceae plants are the commercial source of galanthamine, an alkaloid approved for the clinical treatment of Alzheimer’s disease. The chemistry and bioactivity of Chilean representatives of Rhodophiala genus from the family of Amaryllidaceae have not been widely studied so far. Ten collections of five different Chilean Rhodophiala were analyzed in vitro for activity against enzymes such as acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) as well as for their alkaloid composition by GC-MS. To obtain an insight into the potential AChE and BuChE inhibitory activity of the alkaloids identified in the most active samples, docking experiments were carried out. Although galanthamine was found neither in aerial parts nor in bulbs of R. splendens, these plant materials were the most active inhibitors of AChE (IC₅₀: 5.78 and 3.62 μg/mL, respectively) and BuChE (IC₅₀: 16.26 and 14.37 μg/mL, respectively). Some 37 known alkaloids and 40 still unidentified compounds were detected in the samples, suggesting high potential in the Chilean Amaryllidaceae plants as sources of both novel bioactive agents and new alkaloids.

N-oxide alkaloids from Crinum amabile (Amaryllidaceae)

Natural products play an important role in the development of new drugs. In this context, the Amaryllidaceae alkaloids have attracted considerable attention in view of their unique structural features and various biological activities. In this study, twenty-three alkaloids were identified from Crinum amabile by GC-MS and two new structures (augustine N-oxide and buphanisine N-oxide) were structurally elucidated by NMR. Anti-parasitic and cholinesterase (AChE and BuChE) inhibitory activities of six alkaloids isolated from this species, including the two new compounds, are described herein. None of the alkaloids isolated from C. amabile gave better results than the reference drugs, so it was possible to conclude that the N-oxide group does not increase their therapeutic potential.

Comparative Analysis of Amaryllidaceae Alkaloids from Three Lycoris Species

The major active constituents from Amaryllidaceae family were reported to be Amaryllidaceae alkaloids (AAs), which exhibited a wide spectrum of biological activities, such as anti-tumor, anti-viral, and acetyl-cholinesterase-inhibitory activities. In order to better understand their potential as a source of bioactive AAs and the phytochemical variations among three different species of Lycoris herbs, the HPLC fingerprint profiles of Lycorisaurea (L. aurea), L. radiata, and L. guangxiensis were firstly determined and compared using LC-UV and LC-MS/MS. As a result, 39 peaks were resolved and identified as AAs, of which nine peaks were found in common for all these three species, while the other 30 peaks could be revealed as characteristic AAs for L. aurea, L. radiata and L. guangxiensis, respectively. Thus, these AAs can be used as chemical markers for the identification and quality control of these plant species. To further reveal correlations between chemical components and their pharmaceutical activities of these species at the molecular level, the bioactivities of the total AAs from the three plant species were also tested against HepG2 cells with the inhibitory rate at 78.02%, 84.91% and 66.81% for L. aurea, L. radiata and L. guangxiensis, respectively. This study firstly revealed that the three species under investigation were different not only in the types of AAs, but also in their contents, and both contributed to their pharmacological distinctions. To the best of our knowledge, the current research provides the most detailed phytochemical profiles of AAs in these species, and offers valuable information for future valuation and exploitation of these medicinal plants.

Composition of Carotenoids and Flavonoids in Narcissus Cultivars and their Relationship with Flower Color

Narcissus is widely used for cut flowers and potted plants, and is one of the most important commercial bulbous flowers in the floricultural industry. In this study, ten carotenoid and eighteen flavonoid compounds from the perianths and coronas of fifteen narcissus cultivars were measured by HPLC–APCI-MS/MS and UPLC-Q-TOF-MS/MS. Among these, six carotenoids, a total of seventeen flavonols and chlorogenic acid were identified in narcissus for the first time. A multivariate analysis was used to explore the relationship between flower color and pigment composition. We found that all-trans-violaxanthin and total carotenoid content were the main factors that affected flower color. These investigations could provide a global view of flower color formation and a theoretical basis for hybridization breeding in narcissus.

Antifungal and Antibacterial Activity of Extracts and Alkaloids of Selected Amaryllidaceae Species

Alkaloidal extracts of six selected species of Amaryllidaceae were studied with respect to their antibacterial and anti-yeast activity and their alkaloidal fingerprint. Twenty-five alkaloids were determined by GC/MS, and sixteen of them identified from their mass spectra, retention times and retention indexes. In the antimicrobial assay, Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus were used, along with isolates of the human pathogenic yeasts Candida albicans, C. glabrata, C. dubliniensis and Lodderomyces elongiosporus. The six extracts, together with 19 Amaryllidaceae alkaloids isolated in our laboratory, showed almost no inhibitory activity against the bacteria tested. However, promising anti-yeast properties were detected; the most potent activity was shown by lycorine, which inhibited C. dubliniensis with a MIC of 32 μg/mL, C. albicans and L. elongiosporus, both with MICs of 64 μg/mL, followed by caranine inhibiting C. dubliniensis with a MIC of 128 μg/mL. Among the alkaloidal extracts, Narcissus jonquilla cv. Baby Moon showed the most potent anti-yeast activity, with minimal and average MIC values of 128 and 192 μg/mL, respectively, followed by Leucojum aestivum, Narcissus poeticus var. recurvus and N. canaliculatus (average MICs 256, 267 and 299 μg/mL, respectively). The lowest MIC value among extracts was obtained for N. canaliculatus against L. elongiosporus (MIC 64 μg/mL).

Jonquailine, a new pretazettine-type alkaloid isolated from Narcissus jonquilla quail, with activity against drug-resistant cancer

A new alkaloid, belonging to the pretazettine group of Amaryllidaceae alkaloids, was isolated from dried bulbs of Narcissus jonquilla quail and named jonquailine. Its structure, including the absolute configuration, was elucidated using various NMR, ECD and ESI MS techniques. Initial biological evaluation revealed significant antiproliferative effects against glioblastoma, melanoma, uterine sarcoma and non-small-cell lung cancer cells displaying various forms of drug resistance, including resistance to apoptosis and multi-drug resistance. Jonquailine was also found to synergize with paclitaxel in its antiproliferative action against drug-resistant lung cancer cells. The results obtained compared with literature data also showed that the hydroxylation at C-8 is an important feature for the anticancer activity but this seems unaffected by the stereochemistry or the acetalization of the lactol.

Analysis of Bioactive Amaryllidaceae Alkaloid Profiles in Lycoris Species by GC-MS

The genus Lycoris, a group of Amaryllidaceae plants distributed in temperate regions of Eastern Asia, is already known for containing representative alkaloids typical of this botanical family with a wide range of biological activities (for example, lycorine and galanthamine). In the present work, the alkaloid profiles of nine species, L. albiflora, L. aurea, L. chinensis, L. haywardii, L. incarnata, L. longituba, L. radiata, L. sprengeri, and L. squamigera, and one variety ( L. radiata var. pumila) have been evaluated by GC-MS. Structures belonging to the lycorine-, homolycorine-, haemanthamine-, narciclasine-, tazettine-, montanine- and galanthamine-series were identified and quantified, with galanthamine- and lycorine-type alkaloids predominating and usually showing a high relative abundance in comparison with other alkaloids of the extracts. Interestingly, L. longituba revealed itself to be a potential commercial source of bioactive alkaloids. In general terms, our results are consistent with the alkaloid profiles reported in the literature for previously studied species.

Chemical Composition of Bioactive Alkaloid Extracts from Some Narcissus Species and Varieties and their Biological Activity

Alkaloid extracts of eight Narcissus (Amaryllidaceae) species and varieties were studied with respect to their acetylcholinesterase (HuAChE) and butyrylcholinesterase (HuBuChE) inhibitory activity and alkaloid patterns. Thirty alkaloids were determined by GC/MS, and twenty-five of them identified from their mass spectra, retention times and retention indexes. Promising HuAChE inhibition activity was demonstrated by six Narcissus taxa and HuBuChE inhibition by N. jonquila cv. Double Campernelle and N. nanus cv. Elka with IC50 values of 24.1 ± 1.9 μg/mL and 25.1 ± 1.8 μg/mL, respectively. Two alkaloids were isolated in pure form using preparative TLC and identified as the galanthamine type alkaloid narwedine and the lycorine type alkaloid incartine. Both compounds were tested for their biological activity. They were considered inactive in HuAChE/HuBuChE assays, but showed promising prolyl oligopeptidase inhibition activities with IC50 values of 0.95 ± 0.12 mM and 0.91 ± 0.09 mM, respectively.

Crinine-type alkaloids from Hippeastrum aulicum and H. calyptratum

An ongoing search for alkaloids in the Amaryllidaceae species using GC-MS resulted in the identification of two crinine-type alkaloids, aulicine (1) and 3-O-methyl-epimacowine, (2) from the indigenous Brazilian species Hippeastrum aulicum and Hippeastrum calyptratum, respectively. In addition, two alkaloids, 11-oxohaemanthamine (3) and 7-methoxy-O-methyllycorenine (4) were both isolated from H. aulicum. Furthermore, we provide here complete NMR spectroscopic data for the homolycorine analogues nerinine (5) and albomaculine (6). The absolute stereochemistry of the 5,10b-ethano bridge in the crinine variants was determined by circular dichroism and X-ray crystallographic analysis, thus presenting the first direct evidence for the presence of crinine-type alkaloids in the genus Hippeastrum.

Evolution of alkaloid biosynthesis in the genus Narcissus

In an attempt to reveal the relationships between alkaloid biosynthesis and phylogeny, we investigated by GC-MS the alkaloid patterns of 22 species and 3 hybrids (from 45 locations) from seven main sections of the genus Narcissus (Amaryllidaceae). The results indicate that the first alkaloids to evolve in the genus Narcissus were of the lycorine- and homolycorine-type. The alkaloid pattern of the Nevadensis section supports its recent separation from the Pseudonarcissus section. The plants of Narcissus pallidulus (Ganymedes section) show a predominance of Sceletium-type compounds, which are quite rare in the Amaryllidaceae family. Two successful evolutionary strategies involving alkaloid biosynthesis and leading to an expansion in taxa and occupied area were determined. Firstly, a diversification of alkaloid patterns and a high alkaloid concentration in the organs of the large Narcissus species (in the Pseudonarcissus section) resulted in an improved chemical defence in diverse habitats. Secondly, both plant size and alkaloid biosynthesis were reduced (in the Bulbocodium and Apodanthi sections) relegated to dry pastures and rocky places.

Alkaloids from Habranthus tubispathus and H. jamesonii, two Amaryllidaceae with Acetyl- and Butyrylcholinesterase Inhibition Activity

Alzheimer's disease (AD) is a neurodegenerative disorder associated with memory impairment and cognitive deficit. Most of the drugs currently available for the treatment of AD are acetylcholinesterase (AChE) inhibitors. Plants of the Amaryllidaceae family are known to synthesize alkaloids, which have shown AChE inhibitory activity. Habranthus tubispathus and H. jamesonii are two Amaryllidaceae that can be found growing wild to the southwest of Buenos Aires in Argentina. Acetyl- and butyrylcholinesterase inhibition was observed for the extracts obtained from bulbs of H. tubispathus and bulbs and aerial parts of H. jamesonii. The strongest cholinesterase inhibition was observed for the alkaloid extract obtained from the aerial parts for H. jamesonii (AChE IC50= 0.7 μg/mL; BChE IC50= 6.7 μg/mL). The AChE inhibition observed for H. jamesonii could be explained by the presence of galanthamine and sanguinine, two potent AChE inhibitors. The levels of lycorine and hippeastidine, moderate AChE inhibitors, observed in the bulbs of H. tubispathus could be responsible for the significant AChE inhibition observed. The alkaloids present in these Amaryllidaceae were identified by means of GC-MS analysis. In the case of H. tubispathus, hippeastidine and 3- O-demethylhippeastidine, were isolated and completely characterized by 1H and 13C NMR spectroscopy.

Amaryllidaceae and Sceletium alkaloids

Covering: July 2010 to June 2012. Previous review: Nat. Prod. Rep., 2011, 28, 1126-1142. Recent progress on the isolation, identification, biological activity and synthetic studies of structurally diverse alkaloids from plants of the family Amaryllidaceae is summarized in this review. In addition, the structurally related alkaloids isolated from Sceletium species are discussed as well.

Isolation and Cholinesterase Inhibitory Activity of Narcissus Extracts and Amaryllidaceae Alkaloid

Alkaloid extracts of eleven Narcissus (Amaryllidaceae) species and varieties were studied with respect to their acetylcholinesterase (HuAChE) and butyrylcholinesterase (HuBuChE) inhibitory activity and alkaloid patterns. Forty-two alkaloids were determined by GC/MS, and thirty of them identified from their mass spectra, retention times and retention indexes. Promising HuAChE inhibition activity was demonstrated by nine Narcissus taxa and HuBuChE inhibition by Narcissus poeticus cv. Pink Parasol with an IC50 value of 3.3 ± 0.5 μg/mL. The alkaloid identified as (11C- S)-homolycorine was isolated in pure form from Narcissus Sir W. Churchill using preparative TLC and was tested for its biological activity. Homolycorine inhibited HuAChE and HuBuChE in a dose-dependent manner with IC50 values of 63.7±4.3 μM and 151.0±15.2 μM, respectively.

Isolation and characterization of bioactive compounds from plant resources: the role of analysis in the ethnopharmacological approach

The phytochemical research based on ethnopharmacology is considered an effective approach in the discovery of novel chemicals entities with potential as drug leads. Plants/plant extracts/decoctions, used by folklore traditions for treating several diseases, represent a source of chemical entities but no information are available on their nature. Starting from this viewpoint, the aim of this review is to address natural-products chemists to the choice of the best methodologies, which include the combination of extraction/sample preparation tools and analytical techniques, for isolating and characterizing bioactive secondary metabolites from plants, as potential lead compounds in the drug discovery process. The work is distributed according to the different steps involved in the ethnopharmacological approach (extraction, sample preparation, biological screening, etc.), discussing the analytical techniques employed for the isolation and identification of compound/s responsible for the biological activity claimed in the traditional use (separation, spectroscopic, hyphenated techniques, etc.). Particular emphasis will be on herbal medicines applications and developments achieved from 2010 up to date.