Amaryllidaceae alkaloids as agents with protective effects against oxidative neural cell injury

Mapping of specialized metabolite terms onto a plant phylogeny using text mining and large language models

Plants produce a staggering array of chemicals that are the basis for organismal function and important human nutrients and medicines. However, it is poorly defined how these compounds evolved and are distributed across the plant kingdom, hindering a systematic view and understanding of plant chemical diversity. Recent advances in plant genome/transcriptome sequencing have provided a well-defined molecular phylogeny of plants, on which the presence of diverse natural products can be mapped to systematically determine their phylogenetic distribution. Here, we built a proof-of-concept workflow where previously reported diverse tyrosine-derived plant natural products were mapped onto the plant tree of life. Plant chemical-species associations were mined from literature, filtered, evaluated through manual inspection of over 2500 scientific articles, and mapped onto the plant phylogeny. The resulting "phylochemical" map confirmed several highly lineage-specific compound class distributions, such as betalain pigments and Amaryllidaceae alkaloids. The map also highlighted several lineages enriched in dopamine-derived compounds, including the orders Caryophyllales, Liliales, and Fabales. Additionally, the application of large language models, using our manually curated data as a ground truth set, showed that post-mining processing can largely be automated with a low false-positive rate, critical for generating a reliable phylochemical map. Although a high false-negative rate remains a challenge, our study demonstrates that combining text mining with language model-based processing can generate broader phylochemical maps, which will serve as a valuable community resource to uncover key evolutionary events that underlie plant chemical diversity and enable system-level views of nature's millions of years of chemical experimentation.

Anti-inflammatory effects of the plant family Amaryllidaceae

ETHNOPHARMACOLOGICAL RELEVANCE

Members of the plant family Amaryllidaceae are widely recorded in traditional systems of medicine. Their usage for inflammatory conditions is most prominent, with substantive evidence emerging from several locations around the world.

AIM OF THE STUDY

This survey was undertaken to identify such plant taxa, highlight the countries from which they originate and afford details of the ailments against which they are utilized. The undertaking also sought to establish the in vitro and in vivo activities of Amaryllidaceae plant extracts in inflammation-based assays. Furthermore, it set out to unravel the molecular mechanisms used to explain these effects.

MATERIALS AND METHODS

Over six-hundred articles were identified in searches carried out on SciFinder, Scopus, ScienceDirect, PubMed and Google Scholar. These were condensed to around 170 that formulated the basis of the text. The keyword engaged was 'Amaryllidaceae' in conjunction with 'inflammation' or 'anti-inflammatory', as well as the names of individual genera combined with the latter two.

RESULTS

Fifty-one species from thirty-five countries were identified for their uses against inflammation. Twenty-four of such conditions were discernible, of which their applicability in wound healing and pain management was most conspicuous. The utilization of all plant parts was apparent, preparations of which were used primarily via topical application. Extracts of seventy-three species (from twenty-three genera) were examined in nearly thirty inflammation-based assays where their activities in vitro and in vivo were shown to be significant. They were effective in vivo against pain and swelling as well as wound healing, without detriment towards test subjects. The in vitro studies were carried out mainly in mononuclear cells such as macrophages, leukocytes, lymphocytes and neutrophils against which their cytotoxic effects were seen to be minimal. The modes of operation were shown to involve modulation of both pro-inflammatory (such as NF-κB, TNF-α, IL-6, IFN-γ, COX and NO) and anti-inflammatory (such as IL-10) factors.

CONCLUSIONS

The Amaryllidaceae is showcased as a platform highly conducive towards studies in the inflammation arena. Potent activities in instances were observed via in vitro and in vivo models of study, bolstered by the significant amounts of information emerging from traditional forms of medicine. It is conceivable that the family may yield future anti-inflammatory chemotherapeutics, particularly those related to its alkaloid principles.

Epigenetic regulation exerted by Caliphruria subedentata and galantamine: an in vitro and in silico approach for mimic Alzheimer's disease

At the interface between genes and environment, epigenetic mechanisms, including DNA methylation and histone modification, regulate neurogenic processes such as differentiation, proliferation, and maturation of neural stem cells. However, these mechanisms are altered in Alzheimer's disease (AD), a neurodegenerative condition that mainly affects older adults. Since epigenetic mechanisms are known to be reversible, a number of molecules from natural sources are being studied as epigenetic regulators in AD. Recently, in vitro and in silico studies have shown that C. subedentata and its alkaloids modulated neurotoxicity. However, studies exploring the epigenetic activity of these alkaloids are limited. We conducted a set of bioassays to evaluate neuronal differentiation and the sensitivity of undifferentiated SH-SY5 cells against a neurotoxic stimulus. In addition, we analyzed the methylation profiles in genes such as APP, PSI, and BACE1 due to their role in amyloid processing. Docking and molecular dynamic analysis were used to explore the effect exerted by C. subedentata alkaloids on the regulation of histone deacetylases (HDAC2, HDAC3 and HDAC7). The results demonstrated that C. subedentata and galantamine induce neuronal differentiation and protect the undifferentiated SH-SY5Y cells against Aβ(1-42)-induced neurotoxicity. The methylation profiles of the studied genes show no statistically significant differences between C. subedentata, galantamine. However, these findings should be interpreted with caution, since small changes in methylation promoters in the brain could not be easily detected. Results from in silico approaches describe for the first time the potential promissing epigenetic effects of galantamine by regulating HDAC3 and HDAC7 modification.Communicated by Ramaswamy H. Sarma.

Research Progress on Neuroprotective Effects of Isoquinoline Alkaloids

Neuronal injury and apoptosis are important causes of the occurrence and development of many neurodegenerative diseases, such as cerebral ischemia, Alzheimer's disease, and Parkinson's disease. Although the detailed mechanism of some diseases is unknown, the loss of neurons in the brain is still the main pathological feature. By exerting the neuroprotective effects of drugs, it is of great significance to alleviate the symptoms and improve the prognosis of these diseases. Isoquinoline alkaloids are important active ingredients in many traditional Chinese medicines. These substances have a wide range of pharmacological effects and significant activity. Although some studies have suggested that isoquinoline alkaloids may have pharmacological activities for treating neurodegenerative diseases, there is currently a lack of a comprehensive summary regarding their mechanisms and characteristics in neuroprotection. This paper provides a comprehensive review of the active components found in isoquinoline alkaloids that have neuroprotective effects. It thoroughly explains the various mechanisms behind the neuroprotective effects of isoquinoline alkaloids and summarizes their common characteristics. This information can serve as a reference for further research on the neuroprotective effects of isoquinoline alkaloids.

Amaryllidaceae alkaloids in skin cancer management: Photoprotective effect on human keratinocytes and anti-proliferative activity in melanoma cells

Skin cancer has high rates of mortality and therapeutic failure. In this study, to develop a multi-agent strategy for skin cancer management, the selective cytotoxicity of several alkaloid fractions and pure alkaloids isolated from Amaryllidaceae species was evaluated in melanoma cells. In addition, UVB-stimulated keratinocytes (HaCaT) were exposed to seven alkaloid fractions characterized by GC-MS, and the production of intracellular reactive oxygen species (ROS) and IL-6, were measured to evaluate their photoprotection effects. The Eucharis caucana (bulb) alkaloid fraction (20 μg/ml) had a clear effect on the viability of melanoma cells, reducing it by 45.7% without affecting healthy keratinocytes. This alkaloid fraction and tazettine (both at 2.5 μg/ml) suppressed UVB-induced ROS production by 31.6% and 29.4%, respectively. The highest anti-inflammatory potential was shown by the Zephyranthes carinata (bulb) alkaloid fraction (10 μg/ml), which reduced IL-6 production by 90.8%. According to the chemometric analysis, lycoramine and tazettine had a photoprotective effect on the UVB-exposed HaCaT cells, attenuating the production of ROS and IL-6. These results suggest that Amaryllidaceae alkaloids have photoprotective and therapeutic potential in skin cancer management, especially at low concentrations.

Cytotoxic Activity of Amaryllidaceae Plants against Cancer Cells: Biotechnological, In Vitro, and In Silico Approaches

Cancer is a major cause of death and an impediment to increasing life expectancy worldwide. With the aim of finding new molecules for chemotherapeutic treatment of epidemiological relevance, ten alkaloid fractions from Amaryllidaceae species were tested against six cancer cell lines (AGS, BT-549, HEC-1B, MCF-7, MDA-MB 231, and PC3) with HaCat as a control cell line. Some species determined as critically endangered with minimal availability were propagated using in vitro plant tissue culture techniques. Molecular docking studies were carried out to illustrate binding orientations of the 30 Amaryllidaceae alkaloids identified in the active site of some molecular targets involved with anti-cancer activity for potential anti-cancer drugs. In gastric cancer cell line AGS, the best results (lower cell viability percentages) were obtained for Crinum jagus (48.06 ± 3.35%) and Eucharis bonplandii (45.79 ± 3.05%) at 30 µg/mL. The research focused on evaluating the identified alkaloids on the Bcl-2 protein family (Mcl-1 and Bcl-xL) and HK2, where the in vitro, in silico and statistical results suggest that powelline and buphanidrine alkaloids could present cytotoxic activity. Finally, combining experimental and theoretical assays allowed us to identify and characterize potentially useful alkaloids for cancer treatment.

Chemical Principles of Boophone, Nerine, Crossyne, Clivia, Cryptostephanus, Haemanthus and Scadoxus of the South African Amaryllidaceae and Their Biological Properties

The Amaryllidaceae features prominently amongst bulbous flowering plant families. Accommodating about a third of its species, South Africa affords a sound basis for Amaryllidaceae plant research. Boophone, Nerine, Crossyne, Clivia, Cryptostephanus, Haemanthus and Scadoxus have been well-represented in such endeavors. The account herein summarizes the studies undertaken between 2013 - 2020 on these genera in regards to their chemical and biological characteristics. A total of 136 compounds comprising 63 alkaloids and 73 non-alkaloid entities were described during this period from eighteen members of the title genera. The alkaloids were reflective of the structural diversity found in eight isoquinoline alkaloid groups of the Amaryllidaceae. Of these, the crinane (29 compounds), lycorane and homolycorine (11 compounds each) groups were the most-represented. The non-alkaloid substances were embracive of the same number of unrelated groups including, acids, phenolics, flavonoids and triterpenoids. A wide variety of assays were engaged to ascertain the biological activities of the isolated compounds, notably in regards to cancer and motorneuron-related diseases. There were also attempts made to determine the antimicrobial, anti-inflammatory and antioxidant effects of some of the substances. New information has also emerged on the herbicidal, insecticidal and plant growth regulatory effects of selected alkaloid principles. Coupled to the biological screening measures were in instances probes made to establish the molecular basis to some of the activities, particularly in relation to cancer and Parkinson's disease.

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.

Insights to the tribe Haemantheae of the South African Amaryllidaceae

ETHNOPHARMACOLOGICAL RELEVANCE

The family Amaryllidaceae has been documented in traditional systems of medicine around the globe. Its member tribe Haemantheae occurs chiefly in South Africa, where around twenty of its species are identifiable with a wide variety of functions in such practices.

AIM OF THE STUDY

This account details work published from 2013 to 2020 on the tribe Haemantheae involving Clivia, Cryptostephanus, Haemanthus, Scadoxus and Gethyllis. Focus is maintained on the traditional medicinal aspects, pharmacological activities and identification of the active principles. Significant effort is also made to outline the molecular basis to some of these effects.

MATERIALS AND METHODS

The major search engine platforms including, SciFinder, Scopus, ScienceDirect, PubMed and Google Scholar were utilized at the literature consolidation stage. Keywords engaged in the process included 'Amaryllidaceae' and 'Haemantheae' as well as individual genera and specie names.

RESULTS

Twenty-four species of the five genera were encountered over the designated time frame. New traditional medicinal information has emerged on nine of these species, where usage ranged from the treatment of wounds and infections, circulatory and gastrointestinal issues to AIDS and TB. Significant amounts of new data also appeared in relation to the antimicrobial, anti-inflammatory, antioxidant, anticholinesterase, antidepressive and cytotoxic effects of these plants. Potent activities were observed in some instances, as they were in regards to the anti-inflammatory effects of some Gethyllis species in their cyclooxygenase-inhibitory effects. The entities behind these activities, with few exceptions, were shown to be isoquinoline alkaloids which are known to dominate the chemistry of the Amaryllidaceae. Interesting observations were also made for the mechanisms behind some of the effects, notably in the inflammatory and motorneuron disease arenas.

CONCLUSIONS

The tribe Haemantheae has proved to be a rich and diverse platform for studies of the Amaryllidaceae in the key areas of traditional medicine, pharmacology and phytochemistry. Indigenous knowledge has played a significant role in guiding the biological evaluations, while identification of the active principles has been bolstered by the exceedingly rich alkaloid diversity of the Amaryllidaceae. As such, Haemantheae should continue to feature prominently in drug discovery efforts targeted at the family.

In vitro and in silico analysis of galanthine from Zephyranthes carinata as an inhibitor of acetylcholinesterase

Zephyranthes carinata Herb., a specie of the Amaryllidoideae subfamily, has been reported to have inhibitory activity against acetylcholinesterase. However, scientific evidence related to their bioactive alkaloids has been lacking. Thus, this study describes the isolation of the alkaloids of this plant, and their inhibition of the enzymes acetylcholinesterase (eeAChE) and butyrylcholinesterase (eqBuChE), being galanthine the main component. Additionally, haemanthamine, hamayne, lycoramine, lycorine, tazettine, trisphaeridine and vittatine/crinine were also isolated. The results showed that galanthine has significant activity at low micromolar concentrations for eeAChE (IC₅₀ = 1.96 μg/mL). The in-silico study allowed to establish at a molecular level the high affinity and the way galanthine interacts with the active site of the TcAChE enzyme, information that corroborates the result of the experimental IC₅₀. However, according to molecular dynamics (MD) analysis, it is also suggested that galanthine presents a different inhibition mode that the one observed for galanthamine, by presenting interaction with peripheral anionic binding site of the enzyme, which prevents the entrance and exit of molecules from the active site. Thus, in vitro screening assays plus rapid computer development play an essential role in the search for new cholinesterase inhibitors by identifying unknown bio-interactions between bioactive compounds and biological targets.

Current Trends in Computational Quantum Chemistry Studies on Antioxidant Radical Scavenging Activity

The antioxidative nature of chemicals is now routinely studied using computational quantum chemistry. Scientists are constantly proposing new approaches to investigate those methods, and the subject is evolving at a rapid pace. The goal of this review is to collect, consolidate, and present current trends in a clear, methodical, and reference-rich manner. This paper is divided into several sections, each of which corresponds to a different stage of elaborations: preliminary concerns, electronic structure analysis, and general reactivity (thermochemistry and kinetics). The sections are further subdivided based on methodologies used. Concluding remarks and future perspectives are presented based on the remaining elements.

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

Recent Progress on Biological Activity of Amaryllidaceae and Further Isoquinoline Alkaloids in Connection with Alzheimer's Disease

Alzheimer’s disease (AD) is a progressive age-related neurodegenerative disease recognized as the most common form of dementia among elderly people. Due to the fact that the exact pathogenesis of AD still remains to be fully elucidated, the treatment is only symptomatic and available drugs are not able to modify AD progression. Considering the increase in life expectancy worldwide, AD rates are predicted to increase enormously, and thus the search for new AD drugs is urgently needed. Due to their complex nitrogen-containing structures, alkaloids are considered to be promising candidates for use in the treatment of AD. Since the introduction of galanthamine as an antidementia drug in 2001, Amaryllidaceae alkaloids (AAs) and further isoquinoline alkaloids (IAs) have been one of the most studied groups of alkaloids. In the last few years, several compounds of new structure types have been isolated and evaluated for their biological activity connected with AD. The present review aims to comprehensively summarize recent progress on AAs and IAs since 2010 up to June 2021 as potential drugs for the treatment of AD.

Untargeted GC/MS-based approach for identification of anti-inflammatory alkaloids from Hippeastrum elegans (Amaryllidaceae) using a human neutrophil model

Hippeastrum elegans is an Amaryllidaceae species producing alkaloids with pharmaceutical potential including lycorine and galanthamine. Herein, we developed a non-targeted metabolomic study associated to chemometrics and biological evaluations to identify the H. elegans constituents that were able to reduce the human neutrophils proinflammatory mechanisms. The alkaloid fractions were extracted from bulbs cultivated for 15 months (m) and harvested in six harvest periods (5, 7, 9, 11, 13, and 15 m). The GC-MS analysis allowed the detection of 41 alkaloids being 31 identified. All alkaloid components varied over the cultivation and most of them were lycorine-type skeletons. Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) distinguished three groups according to the chemical profile (group I: 5, 7, and 9 m; group II: 11 m and group III: 13 and 15 m). Therefore, the biological assays were only performed with one of the representative samples of each group: 7 m, 11 m and 15 m. None of them was toxic to human neutrophils by LDH activity and MTT test. The 7 m and 15 m-alkaloid fractions showed anti-inflammatory effects by reducing human neutrophil degranulation. However, the former one was more effective in inhibiting the cell activation based on the reduction of myeloperoxidase (MPO) release and reactive oxygen species (ROS) production. Afterwards, Partial Least Squares analysis (PLS) indicated lycorine and 11,12-dehydro-2-methoxy-assoanine as the compounds responsible for the anti-inflammatory activity of the bioactive fraction. Thus, the 7 m-alkaloid fraction of H. elegans seems to be a promising anti-inflammatory drug that deserves additional research.

Secondary Metabolites with Antioxidant Activities for the Putative Treatment of Amyotrophic Lateral Sclerosis (ALS): "Experimental Evidences"

Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disorder that is characterized by progressive loss of the upper and lower motor neurons at the spinal or bulbar level. Oxidative stress (OS) associated with mitochondrial dysfunction and the deterioration of the electron transport chain are factors that contribute to neurodegeneration and perform a potential role in the pathogenesis of ALS. Natural antioxidant molecules have been proposed as an alternative form of treatment for the prevention of age-related neurological diseases, in which ALS is included. Researches support that regulations in cellular reduction/oxidation (redox) processes are being increasingly implicated in this disease, and antioxidant drugs are aimed at a promising pathway to treatment. Among the strategies used for obtaining new drugs, we can highlight the isolation of secondary metabolite compounds from natural sources that, along with semisynthetic derivatives, correspond to approximately 40% of the drugs found on the market. Among these compounds, we emphasize oxygenated and nitrogenous compounds, such as flavonoids, coumarins, and alkaloids, in addition to the fatty acids, that already stand out in the literature for their antioxidant properties, consisting in a part of the diets of millions of people worldwide. Therefore, this review is aimed at presenting and summarizing the main articles published within the last years, which represent the therapeutic potential of antioxidant compounds of natural origin for the treatment of ALS.

Acetylcholinesterase inhibitory activity, anti-inflammatory, and neuroprotective potential of Hippeastrum psittacinum (Ker Gawl.) herb (Amaryllidaceae)

Hippeastrum psittacinum, Amaryllidaceae, is used in traditional medicine as a purgative, aphrodisiac, and anticough remedy. The ethanol extract (EE) and alkaloid-rich fractions (ARF) from H. psittacinum bulbs were evaluated for their acetylcholinesterase (AChE) inhibition. The EE cytotoxic and anti-inflammatory effects in RAW 264.7 cells, and the neuroprotective and genotoxic activities in SH-SY5Y cells, were also estimated. Fifteen alkaloids were identified in the EE by gas chromatography-mass spectrometry. ARFs were less active for AChE inhibition than EE. The viability of both cell lines was higher than 70% with EE concentrations below 25 μg/mL. The EE decreased nitrite release in RAW cells stimulated with lipopolysaccharide, showing values of 83, 67, and 53% at 6.25, 12.5, and 25 μg/mL, respectively. Furthermore, the EE partially protected SH-SY5Y cells from hydrogen peroxide-mediated deleterious effects by approximately 50% at the same concentrations. The micronucleus assays showed that the extract caused chromosomal missegregation at concentrations above 12.5 μg/mL. The in silico analyses showed that some alkaloids presented properties of permeation of the blood-brain barrier and the intestine. Our findings present new evidence of the potential of H. psittacinum potential as an AChE inhibitor, as well as an anti-inflammatory and neuroprotective agent.