Annonacin in Asimina triloba fruit: implication for neurotoxicity

An evaluation of the quality of Annona muricata leaf products

OBJECTIVES

Annona muricata, also known as graviola, is traditionally used for the treatment of a range of disorders including cancer. Interest in A. muricata use has increased in recent years. This study investigated the quality and safety of a selection of commercially available A. muricata leaf products.

METHODS

Seven commercially available products were purchased via online shopping sites. Each product was assessed for quality indicators including weight variation, quantification of the bioactive constituent annonacin, presence of annonaceous acetogenins and contaminants. The samples were evaluated by thin-layer chromatography, high-performance liquid chromatography, liquid chromatography-mass spectroscopy, low-resolution mass spectrometry and nuclear magnetic resonance spectroscopy. Microbial analysis was carried out in accordance with the British Pharmacopoeia. Heavy metals were analysed by inductive coupled plasma mass spectrometry.

KEY FINDINGS

Of the seven products analysed, one product contained less than half of the content stated on the label. The labelled dosage recommendation varied between products. There was a high variation in annonacin concentration (1.05-3.09 mg/g) and the presence of annonaceous acetogenins. One of the products was found to have a total aerobic microbial count above the United States Pharmacopoeia limit.

CONCLUSIONS

The variation in the indicators of quality and safety of commercially available A. muricata leaf products tested have implications for clinicians and people living with cancer who use these herbal products.

Natural Acetogenins, Chatenaytrienins-1, -2, -3 and -4, Mitochondrial Potential Uncouplers and Autophagy Inducers-Promising Anticancer Agents

The present paper details the complete stereoselective synthesis of four natural acetogenins, chatenaytrienins-1, -2, -3 and -4, previously isolated from the roots of fruit trees of the family Annonaceae (A. nutans and A. muricata), as an inseparable mixture. The novel organometallic reactions, developed by the authors, of Ti-catalyzed cross-cyclomagnesiation of O-containing and aliphatic allenes using available Grignard reagents were applied at the key stage of synthesis. We have studied the biological activity of the synthesized individual chatenaytrienins-1, -2, -3 and -4 in vitro, including their cytotoxicity in a panel of tumor lines and their ability to induce apoptosis, affect the cell cycle and mitochondria, and activate the main apoptotic signaling pathways in the cell, applying modern approaches of flow cytometry and multiplex analysis with Luminex xMAP technology. It has been shown that chatenaytrienins affect mitochondria by uncoupling the processes of mitochondrial respiration, causing the accumulation of ROS ions, followed by the initiation of apoptosis. The most likely mechanism for the death of cortical neurons from the consumption of tea from the seeds of Annona fruit is long-term chronic hypoxia, which leads to the development of an atypical form of Parkinson's disease that is characteristic of the indigenous inhabitants of Guam and New Caledonia.

Annonaceae Consumption Worsens Disease Severity and Cognitive Deficits in Degenerative Parkinsonism

BACKGROUND

High consumption of Annona muricata fruit has been previously identified as a risk factor for atypical parkinsonism in the French Caribbean islands.

OBJECTIVE

We tested whether consumption of Annonaceae products could worsen the clinical phenotype of patients with any form of degenerative parkinsonism.

METHODS

We analyzed neurological data from 180 Caribbean parkinsonian patients and specifically looked for dose effects of lifelong, cumulative Annonaceae consumption on cognitive performance. Using unsupervised clustering, we identified one cluster with mild/moderate symptoms (N = 102) and one with severe symptoms including cognitive impairment (N = 78).

RESULTS

We showed that even low cumulative consumption of fruits/juices (>0.2 fruit-years) or any consumption of herbal tea from Annonaceae worsen disease severity and cognitive deficits in degenerative parkinsonism including Parkinson's disease (OR fruits-juices: 3.76 [95% CI: 1.13-15.18]; OR herbal tea: 2.91 [95% CI: 1.34-6.56]).

CONCLUSION

We suggest that more restrictive public health preventive recommendations should be made regarding the consumption of Annonaceae products. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Environmental Risk Factors for Progressive Supranuclear Palsy

Typically, progressive supranuclear palsy (PSP) is clinically characterized by slow vertical saccades or supranuclear gaze palsy, levodopa-resistant parkinsonism with predominant axial symptoms, and cognitive executive impairment. Over the past decades, various PSP phenotypes, including PSP with predominant parkinsonism, PSP with corticobasal syndrome, PSP with progressive gait freezing, and PSP with predominant frontal dysfunction, have been identified from pathologically confirmed cases. Expanding knowledge led to new diagnostic criteria for PSP that with increased disease awareness led to increased PSP prevalence estimates. The identification of environmental and modifiable risk factors creates an opportunity to intervene and delay the onset of PSP or slow disease progression. To date, despite the increasing number of publications assessing risk factors for PSP, few articles have focused on environmental and lifestyle risk factors for this disorder. In this article, we reviewed the literature investigating the relationship between PSP and several environmental and other modifiable lifestyle risk factors. In our review, we found that exposures to toxins related to diet, metals, well water, and hypertension were associated with increased PSP risk. In contrast, higher education and statins may be protective. Further case-control studies are encouraged to determine the exact role of these factors in the etiopathogenesis of PSP, which in turn would inform strategies to prevent and reduce the burden of PSP.

An Overview of the Chemical Characteristics, Bioactivity and Achievements Regarding the Therapeutic Usage of Acetogenins from Annona cherimola Mill

Annona cherimola Mill., or the custard apple, is one of the species belonging to the Annonaceae family, is widely used in traditional medicine, and has been reported to be a valuable source of bioactive compounds. A unique class of secondary metabolites derived from this family are Annonaceous acetogenins, lipophilic polyketides considered to be amongst the most potent antitumor compounds. This review provides an overview of the chemical diversity, isolation procedures, bioactivity, modes of application and synthetic derivatives of acetogenins from A. cherimola Mill.

Effects of Acetogenins from Annona coriacea on the in Vitro Reactions of Photosynthesis

Our search for candidates for photosynthesis inhibitors is allowing us to report the effect of two acetogenins identified in Annona coriacea Mart. leaves, ACG-A and ACG-B, a non-adjacent bis-THF and a mono-THF types, respectively. This is an important class of natural products which presents biological properties such as anticancer, neurotoxic, larvicidal and insecticidal. However, this is only the second report associated to its herbicidal activity. Their mechanisms of action on the light reactions of the photosynthesis were elucidated by polarographic techniques. Compounds inhibited the noncyclic electron transport on basal, phosphorylating, and uncoupled conditions from H₂ O to methyl viologen (MV); therefore, they act as Hill reaction inhibitors. Studies on fluorescence of chlorophyll a (ChL a) indicated that they inhibited the acceptor side of PSII between P680 and PQ-pool, exactly as the commercial herbicide DCMU does.

Acetogenins from Annonaceae family. Their potential biological applications

The aim of this contribution has been to continue with the knowledge about newly isolated acetogenins from Annonaceae family for the last fifteen years. This review will report classification, extraction, isolation, elucidation of the structure, biological activities and mechanism of action of such interesting natural products. In fact, out of the 532 compounds reviewed, 115 previously non-described annonaceous acetogenins have been added to the list of isolated compounds from 2005 to May 2019.

IACS-010759, a potent inhibitor of glycolysis-deficient hypoxic tumor cells, inhibits mitochondrial respiratory complex I through a unique mechanism

The small molecule IACS-010759 has been reported to potently inhibit the proliferation of glycolysis-deficient hypoxic tumor cells by interfering with the functions of mitochondrial NADH-ubiquinone oxidoreductase (complex I) without exhibiting cytotoxicity at tolerated doses in normal cells. Considering the significant cytotoxicity of conventional quinone-site inhibitors of complex I, such as piericidin and acetogenin families, we hypothesized that the mechanism of action of IACS-010759 on complex I differs from that of other known quinone-site inhibitors. To test this possibility, here we investigated IACS-010759's mechanism in bovine heart submitochondrial particles. We found that IACS-010759, like known quinone-site inhibitors, suppresses chemical modification by the tosyl reagent AL1 of Asp160 in the 49-kDa subunit, located deep in the interior of a previously proposed quinone-access channel. However, contrary to the other inhibitors, IACS-010759 direction-dependently inhibited forward and reverse electron transfer and did not suppress binding of the quinazoline-type inhibitor [125I]AzQ to the N terminus of the 49-kDa subunit. Photoaffinity labeling experiments revealed that the photoreactive derivative [125I]IACS-010759-PD1 binds to the middle of the membrane subunit ND1 and that inhibitors that bind to the 49-kDa or PSST subunit cannot suppress the binding. We conclude that IACS-010759's binding location in complex I differs from that of any other known inhibitor of the enzyme. Our findings, along with those from previous study, reveal that the mechanisms of action of complex I inhibitors with widely different chemical properties are more diverse than can be accounted for by the quinone-access channel model proposed by structural biology studies.

Evaluation of nutritional characteristics and bioactive compounds of soursop-yoghurt and soursop-frozen dessert

The nutritional quality, sensory attributes, polyphenols and acetogenins content in yoghurt and frozen dessert formulated with soursop pulp were investigated. The addition of soursop pulp to yoghurt and frozen dessert improved the sensory attributes and the nutritional quality of soursop dairy products resulting in a composition of 0.92 and 2.17% of dietary fiber, 11.25 and 9.84 mg/100 g of vitamin C as well as 243.02 and 490.98 mg/100 g of total polyphenols, respectively. Acetogenins were extracted from both dairy products using maceration, sonication, microwave and Soxhlet. Sonication showed to be faster and safer than the other methods for acetogenins extraction. Higher annonacin (an acetogenin) content was found in yoghurt (38 ng/g) than in frozen dessert (15 ng/g). The quantification of bioactive compounds implied the nutraceutical properties to yoghurt and ice cream when they are added with soursop pulp. The results are useful for the consumers seeking healthier foods.

Antiangiogenic Activity and Chemical Derivatization of the Neurotoxic Acetogenin Annonacin Isolated from Asimina triloba

Annonacin (1) was isolated from the North American pawpaw ( Asimina triloba), as reported earlier from these laboratories. Natural 1 was submitted to the rat aortic ring bioassay for evaluation of antiangiogenic activity and was found to inhibit microvessel growth (IC₅₀ value of 3 μM). 4,10,15,20-Tetraazido derivatives of 1 were prepared by permesylation followed by azide displacement or by iodination followed by azide displacement. The tetraazide derived from mesylation/azidation was antiangiogenic, while that derived from iodination/azidation exhibited no appreciable activity. The membrane permeability of natural 1 was evaluated using the parallel artificial membrane permeability assay and was found to be marginally permeable as compared to several clinically relevant compounds.

Targeted and non-targeted analysis of annonaceous alkaloids and acetogenins from Asimina and Annona species using UHPLC-QToF-MS

In current work, targeted and non-targeted analysis of alkaloids and acetogenins from methanolic extracts of Asimina, Annona species and dietary supplements have been performed using UHPLC-QToF in positive ion mode. Thirty-five standard compounds (twelve alkaloids and twenty-three acetogenins) were used for the analysis. The fragment ions produced by collision induced dissociation (CID) revealed the characteristic cleavage and provided structural information. Aporphine alkaloids and acetogenins are the major groups found in Asimina and Annona species. An untargeted analysis based on high-resolution mass spectrometry was carried out to profile the alkaloids and acetogenins from Asimina species (As. triloba, As. parviflora). Magnoflorine, being a major alkaloid from twigs of As. triloba samples, was used as an example to discuss the fragmentation patterns. In (+)-ESI-MS, magnoflorine gave [M]⁺ ions at m/z 342.1705. The fragment ions at m/z 297.1127 [M-(CH₃)₂NH]⁺, 282.0886 [M-(CH₃)₃NH]⁺, 265.0865 [M-(CH₃)₂NH-CH₃OH]⁺, 237.0916 [M-(CH₃)₂NH-CH₃OH-CO]⁺, and 222.0681 [M-(CH₃)₂NH-CH₃OH-CO-CH₃]⁺ resulted from the [M]⁺ molecular ion. One dietary supplement claiming to contain paw paw (As. triloba) was also analyzed and showed a similar profile to twigs of As. triloba. A total of 131 compounds including standard compounds were identified from the different parts of As. triloba and As. parviflora samples. These compounds can be used to distinguish Asimina species. However, for definite identification of these unknown components, further investigation is required. This may provide a model for the rapid screening and structural characterization of bioactive constituents from plant extracts in a single analysis.

Correlation Between Acetogenin Content and Antiproliferative Activity of Pawpaw (Asimina triloba [L.] Dunal) Fruit Pulp Grown in Korea

Pawpaw (Asimina triloba [L.] Dunal) is widely cultivated in Korea for its fruit, which contains bioactive compounds, such as acetogenins. In this study, we investigated the acetogenin content and antiproliferative activity of pawpaw fruit pulp against various cancer cell lines and evaluated the relationship between these two variables at different maturation stages. Unripe fruit had higher antiproliferative activity than ripe fruit, and the activity level depended on acetogenin content. In addition, the presence of specific acetogenins was related to inhibition of certain cancer cell types. The unripe fruit methanol and ethanol extracts (URFM and URFE, respectively) that were rich in acetogenins strongly inhibited the growth of HT-1080, HeLa, and AGS cells by >50% at concentrations of less than 115 μg/mL. These findings indicate that URFM and URFE have therapeutic potential for the treatment of cancer, and our study establishes a basis for further mechanistic studies of the antiproliferative activity of pawpaw fruit. However, it is necessary to further study the anticancer activity of acetogenins from pawpaw fruit using in vivo activity approaches.

PRACTICAL APPLICATION

Pawpaw (Asimina triloba) contains acetogenins that can inhibit the growth of cancer cells. In our study, we demonstrate that the antiproliferative activity is higher in unripe than in ripe fruit and depends on acetogenin content. Our results indicate that the extract of unripe pawpaw fruit has value not only as a functional food, but has therapeutic potential for the treatment of cancer as a naturally derived substance that may be less toxic than conventional chemotherapy drugs.

Mitochondria: A Common Target for Genetic Mutations and Environmental Toxicants in Parkinson's Disease

Parkinson's disease (PD) is a devastating neurological movement disorder. Since its first discovery 200 years ago, genetic and environmental factors have been identified to play a role in PD development and progression. Although genetic studies have been the predominant driving force in PD research over the last few decades, currently only a small fraction of PD cases can be directly linked to monogenic mutations. The remaining cases have been attributed to other risk associated genes, environmental exposures and gene-environment interactions, making PD a multifactorial disorder with a complex etiology. However, enormous efforts from global research have yielded significant insights into pathogenic mechanisms and potential therapeutic targets for PD. This review will highlight mitochondrial dysfunction as a common pathway involved in both genetic mutations and environmental toxicants linked to PD.

Annona muricata leaves extracts prevent DMBA/TPA-induced skin tumorigenesis via modulating antioxidants enzymes system in ICR mice

Annona muricata, locally known as soursop has been reported to exhibit antiproliferative activities against various cancer cell lines. In this current study, we have investigated the antitumor promotion of various fractions of Annona muricata leaves (AML); hexane (AMLH), dichloromethane (AMLD) and methanol (AMLM) fraction respectively on 7, 12-dimethylbenz[α]anthracene (DMBA) induced and 12-0-tetradecaboylphorbol-13-acetate (TPA) promoted skin tumorigenesis in mice via morphological assessment, biochemical analysis and histopathological evaluation. The results of the study revealed significant inhibition in tumor incidence, tumor burden and tumor volume in the groups received AMLH and AMLD, respectively, and suppressive effects in group received AMLM compared with carcinogen control group at week 21. Superoxide dismutase, catalase, and lipid peroxidation levels were returned to near normal by administration of AML to DMBA/TPA-induced mice. The above findings were supported by histopathological studies, in which the extensive epidermal hyperplasia in carcinogen control group was restored to normal in AML treated groups. Whilst, annonacin, a major annaonaceous acetogenin was found to be the highest in AMLH and AMLD. From the present study, it can be inferred that AML supressed DMBA/TPA-induced skin tumor and this antitumor-promoting activity may be linked to the antioxidant/free radical-scavenging constituents of the extract and annonacin contained in the extracts.

1 H qNMR Quantification of Annonaceous Acetogenins in Crude Extracts of Annona muricata L. Fruit Pulp

INTRODUCTION

Annonaceous acetogenins (AAGs) constitute a group of environmental neurotoxins, possibly implicated in sporadic atypical Parkinsonism/dementia complexes. The recent evidencing of complex mixtures of AAGs in edible fruits and derived food products requires efficient and practical analytical tools for an estimation of human exposure.

OBJECTIVE

To develop a simple method for the direct quantitation of the majority of AAGs (sub-types 1a and 1b) within crude extracts, using commonly available ¹ H-NMR spectrometers, for food control.

METHODOLOGY

Method development was carried out on 400 MHz and 300 MHz spectrometers, for routine application on fruits crude extracts of Annona muricata L. The method was validated with annonacin and squamocin as reference compounds. Two internal standards (ISs), fumaric acid and dimethyl fumarate, were successfully used, in deuterated methanol (CD₃ OD) and deuterated chloroform (CDCl₃ ), respectively.

RESULTS

Quantitation was carried out using signals corresponding to the deshielded ethylenic protons characterising most AAGs, at δ 7.18 or δ 6.98 ppm in CDCl₃ . The limit of quantification (LOQ) was 2.5 mM, with acceptable accuracy, and the limit of detection (LOD) was 0.5 mM. The AAGs contents measured in seven distinct fruit samples of Annona muricata ranged from 14 μmol to 226 μmol of AAGs per 100 g fresh pulp (i.e. 0.14 mmol to 1.3 mmol of AAGs per fruit).

CONCLUSION

A simple, accurate and specific method for quantification of AAGs content was developed and validated for routine application to fruit pulp crude extracts. Copyright © 2017 John Wiley & Sons, Ltd.

Quantification of the environmental neurotoxin annonacin in Rat brain by UPLC-MS/MS

The Annonaceous acetogenin annonacin is an environmental neurotoxin identified in the pulp of several fruits of the Annonaceae family, whose consumption was linked to the occurrence of sporadic atypical Parkinsonism with dementia. A method for its quantification in Rat brain homogenates by UPLC-MS/MS in selected reaction monitoring (SRM) mode was developed and validated. This method was applied to the quantitation of annonacin in Rat brain after intravenous (0.5 mg/kg) and oral (10 mg/kg, 100 mg/kg) administration.

Acetogenins from Annonaceae

In recent decades, annonaceous acetogenins have become highly studied plant secondary metabolites in terms of their isolation, structure elucidation, synthesis, biological evaluation, mechanism of action, and toxicity. The aim of the present contribution is to summarize chemical and biological reports published since 1997 on annonaceous acetogenins and synthetic acetogenin mimics. The compounds are considered biologically in terms of their cytotoxicity for cancer cell lines, neurotoxicity, pesticidal effects, and miscellaneous activities.

Method development for quantification of the environmental neurotoxin annonacin in Rat plasma by UPLC-MS/MS and application to a pharmacokinetic study

Annonacin is an environmental neurotoxin identified in the pulp of several fruits of the Annonaceae family (for example in Annona muricata, Asimina triloba), whose consumption was linked with the occurrence of sporadic atypical Parkinsonism with dementia. Pharmacokinetic parameters of this molecule are unknown. A method for its quantification in Rat plasma was developed, using its analogue annonacinone as an internal standard. Extraction from plasma was performed using ethylacetate with a good recovery. Quantification was performed by UPLC-MS/MS in SRM mode, based on the loss of the γ-methyl-γ-lactone (-112amu) from the sodium-cationized species [M+Na](+) of both annonacin and internal standard. The limit of quantification was 0.25ng/mL. Despite strong matrix effects, a good linearity was obtained over two distinct ranges 0.25-10ng/mL and 10-100ng/mL. The intra- and inter-day precisions (RSD) were lower than 10%, while accuracy was within ±10%. This method was applied to a pharmacokinetic study in the Rat. After oral administration of 10mg/kg annonacin, a Cmax of 7.9±1.5ng/mL was reached at Tmax 0.25h; T1/2 was 4.8±0.7h and apparent distribution volume was 387.9±64.6L. The bioavailability of annonacin was estimated to be 3.2±0.3% of the ingested dose.

Neurotoxicity of Dietary Supplements from Annonaceae Species

Dietary supplements containing plant materials of Annonaceae species (Annona muricata L., A. squamosa L., A. mucosa JACQ., A. squamosa × cherimola Mabb.) were extracted by hot, pressurized ethyl acetate and analyzed for their effect in vitro on Lund human mesencephalic neurons. Cell viability was measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and cell death was determined by lactate dehydrogenase levels. Three supplements strongly decreased the cell viability at extract concentrations of 1 µg/mL, of which 1 decreased cell viability at 0.1 µg/µL. Also, strong neuronal toxicities of these supplements were found. Cell death was observed at concentrations of 10 µg/mL. The degree of toxicity was comparable to the ones found in Annonaceous fruit extracts. Two fruit pulps of Annonaceae (A. muricata and A. squamosa) showed a reduction in cell viability at lower concentrations. The fruit pulp extract of A. muricata revealed the strongest neurotoxic effect, with 67% cell death at a concentration of 1 µg/mL. A high reduction in cell viability coupled with pronounced cell death was found at 0.1 µg/mL for an Annonaceous seed extract. These results demonstrate that the intake of dietary supplements containing plant material from Annonaceae may be hazardous to health in terms of neurotoxicity.

Determination of Neurotoxic Acetogenins in Pawpaw (Asimina triloba) Fruit by LC-HRMS

The concentrations of the neurotoxins, annonacin and squamocin, were determined in a lyophilized sample of the fruit pulp of the North American pawpaw (Asimina triloba) by LC coupled to high resolution mass spectrometry or LC-HRMS. The sample was extracted using dry methanol at 100 °C and 10 MPa pressure in a sealed container. The extraction of annonacin and squamocin was optimal at 100 °C with 7.72 and 0.162 mg/g, respectively, being found. Also, several isomers of annonacin and squamocin were separated and detected but not quantified.

Identification of the environmental neurotoxins annonaceous acetogenins in an Annona cherimolia Mill. Alcoholic Beverage Using HPLC-ESI-LTQ-Orbitrap

Epidemiological and toxicological studies have suggested Annonaceaeous acetogenins to be environmental neurotoxins responsible for sporadic atypical parkinsonism/dementia in tropical areas. These compounds are present in the tropical genus Annona (Annonaceae), known for its fruit-yielding cultivated species such as Annona cherimolia. This species is widely cultivated in South America, Spain, and Portugal and yields acetogenins in its seeds, stems, and roots. The presence of these compounds in the pulp of its fruit and in derived food products is unclear. An innovative and sensitive methodology by HPLC-ESI-LTQ-Orbitrap with postcolumn infusion of lithium iodide was used to identify the presence of low levels of acetogenins in an A. cherimolia Mill. fruit-based commercial alcoholic beverage. More than 80 representatives were detected, and the 31 most intense acetogenins were identified. All together these findings indicate that this species should be considered as a risk factor within the framework of a worldwide problem of food toxicity.

Comprehensive characterization of Annonaceous acetogenins within a complex extract by HPLC-ESI-LTQ-Orbitrap® using post-column lithium infusion

Annonaceous acetogenins (AAGs) are a homogenous class of polyketides proposed as environmental neurotoxins. Previous dereplication studies of AAGs were limited by the use of low-resolution mass spectrometers. Only poor information in terms of structures was provided due to the limited fragmentation of protonated or sodium cationized species. An innovative approach, using reversed-phase high-performance liquid chromatography coupled to a hybrid linear ion trap/orbitrap mass spectrometer (LTQ-Orbitrap®), was therefore performed. Sensitivity was enhanced by post-column infusion of lithium, since AAGs have a high affinity for this cation. High level of structural information was obtained from low-energy-collision-induced dissociation fragmentation experiments of lithium-cationized AAGs ([M + Li](+) ions) as demonstrated with purified standards. The method was then applied to a total ethyl-acetate extract prepared from commercial soursop nectar (Annona muricata L.). The sensitivity, mass accuracy and specific fragmentation patterns proved to be particularly useful for characterization of the AAGs. Typical structural identification procedure and unexpected observations for specific structural types are illustrated, with major and minor compounds.