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

Alkaloid Profile, Anticholinesterase and Antioxidant Activities, and Sexual Propagation in Hieronymiella peruviana (Amaryllidaceae)

Hieronymiella peruviana, a recently described endemic species from southern Peru, belongs to the Amaryllidaceae family and is known for its diversity of alkaloids. Amaryllidoideae have been studied for their diverse biological activities, particularly for their properties in treating neurodegenerative diseases. This work examines the alkaloidal profile using GC-MS and UPLC-MS/MS of alkaloid-enriched extracts obtained from the leaves and bulbs of H. peruviana and their inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) enzymes. In addition, the phenolic and flavonoid content in the methanolic extract from bulbs was quantified and the antioxidant capacity was evaluated. Moreover, the seed germination was investigated under four temperature conditions (15, 20, 25, and 30 °C). Twenty-two alkaloids, most of them of the homolycorine- and galanthamine-type, including galanthamine, were identified in the alkaloid extracts by means of GC-MS and UPLC-MS/MS analysis. Lycorine and 8-O-Demethylhomolycorine were the most abundant alkaloids in the bulbs and leaves, respectively. The leaves and bulbs alkaloid extracts demonstrated strong AChE inhibition (IC50 = 5.20-8.60 µg/mL) and moderate BuChE inhibition (IC50 = 90.20-122.76 µg/mL). The bulbs' methanolic extract exhibited mild antioxidant activity, showing 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) values of 16.36% at 500 μg/mL and 58.31 mg Trolox equivalents (TE)/g, respectively. Seed germination was most effective at 20 °C and 25 °C. Finally, 60 days after germination, the survival rate of H. peruviana seedlings was 48.33%. These findings establish H. peruviana as a promising source of bioactive alkaloids with potential pharmacological and therapeutic applications, as well as providing critical insights for its propagation and conservation.

Navigating Amaryllidaceae alkaloids: bridging gaps and charting biosynthetic territories

Amaryllidaceae alkaloid (AA) biosynthesis has garnered significant attention in recent years, particularly with the commercialization of galanthamine as a treatment for the symptoms of Alzheimer's disease. A significant amount of research work over the last eight decades has focused on the understanding of AA biosynthesis, starting from early radiolabelling studies to recent multi-omics analysis with modern biotechnological advancements. Those studies enabled the identification of hundreds of metabolites, the characterization of biochemical pathways, and an understanding of the environmental stimuli and of the molecular regulation of these pharmaceutically and agriculturally important metabolites. Despite numerous studies, there remain significant gaps in understanding the biosynthesis of AAs in Amaryllidaceae plants. As such, further research is needed to fully elucidate the metabolic pathways and facilitate their production. This review aims to provide a comprehensive summary of the current state of knowledge on AA biosynthesis, from elicitation of expression of transcription factors in the cell nucleus to alkaloid transport in the apoplast, and to highlight the challenges that need to be overcome for further advancement.

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.

Carbon quantum dot with co-doped nitrogen and phosphorus for tazettine ratiometric fluorescent sensing

An overdose of tazettine (TZ) has toxic side effects, which makes it extremely important to rapidly and subtly determine the TZ. In this study, double-emitting, nitrogen-phosphorus co-doped carbon quantum dots (N,P-CQDs) were prepared using cis-butenedioic acid, phosphoric acid, and p-phenylenediamine. An effective inner filter effect (IFE) can occur between TZ and N,P-CQDs, resulting in their fluorescence quench. Therefore, a ratio fluorescent probe was constructed for detecting the TZ was constructed. After optimizing the experimental conditions, the quenching efficiency showed a strong linear connection with the TZ concentration in the range of 0.01-30 µmol/L, with the detection limit of 0.002 µmol/L. This method could be satisfactorily applied to detect TZ in mouse plasma samples.

Pharmacological and toxicological effects of Amaryllidaceae

The Amaryllidaceae family is widely distributed in the tropics, presenting biological activity attributed mostly to alkaloids, such as an important inhibitory activity of acetylcholinesterase (AChE), antifungal, antibacterial, and cytotoxic activities. The present study aims to review the spectrum of action of the main biological activities and toxicity of secondary metabolites found in Amaryllidaceae through a literature review, using Prisma and the descriptors "Pharmacological effects of Amaryllidaceae" and "Amaryllidaceae family" and "Pharmacological actions of Amaryllidaceae", used in English and Portuguese. The literature search was done in March and May 2023. Original works published from 2012 to 2023, available in full, and presenting experimental and clinical studies were included. After the selection considering the inclusion and exclusion criteria, 60 articles fulfilled the defined criteria. From a pharmacological point of view, the highlight is due to the alkaloid galantamine, which has the potential- and is already used - for treating Alzheimer's. The toxicological aspect must be considered and evaluated carefully, as alkaloids have been associated with adverse effects such as nausea, vomiting, diarrhea, abdominal pain, and cardiovascular, neurological, and respiratory changes. Furthermore, some studies indicate that consuming these plants in significant quantities can lead to hepatic and renal toxicity. Therefore, the therapeutical use of this family's plant drugs and derivatives requires further studies to elucidate its effects and point out metabolites with therapeutic potential.

Chemical Survey of Three Species of the Genus Rauhia Traub (Amaryllidaceae)

Plant biodiversity is an important source of compounds with medicinal properties. The alkaloid galanthamine, first isolated from Galanthus woronowii (Amaryllidaceae), is approved by the FDA for the palliative treatment of mild to moderate Alzheimer's disease due to its acetylcholinesterase (AChE) inhibitory activity. Obtaining this active pharmaceutical ingredient, still sourced on an industrial scale from the Amaryllidaceae species, is a challenge for pharmaceutical companies due to its low natural yield and the high cost of its synthesis. The aim of this work was to determine the alkaloid profile of three different Rauhia (Amaryllidaceae) species collected in Peru, and to assess the potential application of their extracts for the treatment of Alzheimer's disease. The alkaloids were identified by gas chromatography coupled to mass spectrometry (GC-MS), and the AChE inhibitory activity of the extracts was analyzed. Thirty compounds were quantified from the Rauhia species, the R. multiflora extract being the most interesting due to its high diversity of galanthamine-type structures. The R. multiflora extract was also the most active against AChE, with the half maximal inhibitory concentration (IC₅₀) values of 0.17 ± 0.02 μg·mL^-1 in comparison with the IC₅₀ values of 0.53 ± 0.12 μg·mL^-1 for galanthamine, used as a reference. Computational experiments were carried out on the activity of the galanthamine-type alkaloids identified in R. multiflora toward five different human AChE structures. The simulation of the molecules 3-O-acetylgalanthamine, 3-O-acetylsanguinine, narwedine, and lycoraminone on the 4EY6 crystal structure theoretically showed a higher inhibition of hAChE and different interactions with the active site compared to galanthamine. In conclusion, the results of this first alkaloid profiling of the Rauhia species indicate that R. multiflora is an important natural source of galanthamine-type structures and could be used as a model for the development of biotechnological tools necessary to advance the sustainable production of galanthamine.

Cytotoxicity and Antiviral Properties of Alkaloids Isolated from Pancratium maritimum

Ten Amaryllidaceae alkaloids (AAs) were isolated for the first time from Pancratium maritimum collected in Calabria region, Italy. They belong to different subgroups of this family and were identified as lycorine, which is the main alkaloid, 9-O-demethyllycorine, haemanthidine, haemanthamine, 11-hydroxyvittatine, homolycorine, pancracine, obliquine, tazettine and vittatine. Haemanthidine was isolated as a scalar mixture of two 6-epimers, as already known also for other 6-hydroxycrinine alkaloids, but for the first time they were separated as 6,11-O,O′-di-p-bromobenzoyl esters. The evaluation of the cytotoxic and antiviral potentials of all isolated compounds was undertaken. Lycorine and haemanthidine showed cytotoxic activity on Hacat cells and A431 and AGS cancer cells while, pancracine exhibited selective cytotoxicity against A431 cells. We uncovered that in addition to lycorine and haemanthidine, haemanthamine and pancracine also possess antiretroviral abilities, inhibiting pseudotyped human immunodeficiency virus (HIV)−1 with EC50 of 25.3 µM and 18.5 µM respectively. Strikingly, all the AAs isolated from P. maritimum were able to impede dengue virus (DENV) replication (EC50 ranged from 0.34−73.59 µM) at low to non-cytotoxic concentrations (CC50 ranged from 6.25 µM to >100 µM). Haemanthamine (EC50 = 337 nM), pancracine (EC50 = 357 nM) and haemanthidine (EC50 = 476 nM) were the most potent anti-DENV inhibitors. Thus, this study uncovered new antiviral properties of P. maritimum isolated alkaloids, a significant finding that could lead to the development of new therapeutic strategies to fight viral infectious diseases.