Annonacin, Soursop and Parkinsonism: What the Guadeloupe Studies Found

Annonacin is the most abundant of the annonaceous acetogenins, a family of fatty compounds in soursop seeds, leaves and pulp, and it blocks complex I of the mitochondrial respiratory chain, the target of the chemicals used to model Parkinson's disease in the laboratory. Since 1999, studies in Guadeloupe, Martinique and French Guiana have found that people with an unusual, levodopa-resistant parkinsonism had eaten more soursop fruit and drunk more leaf tea than people with Parkinson's disease or no neurological illness. These are observational studies: they show an association, not proof that soursop caused the illness. The French food safety agency in 2010 and an EFSA-hosted review in 2020 both concluded that no safe intake can be set.^{1, 2, 16} This page is the evidence spine of the Wellgard soursop guide.

Evidence at a glance

• People: observational studies only, 87 to 372 patients each, 1999 to 2026.
• Animals: rats, 28 days of intravenous annonacin, 31.7% loss of nigral dopamine neurons; mice, 12 months of soursop juice, tau phosphorylation.
• Agencies: AFSSA (28 April 2010) and EU-FORA (2020): no safe intake can be set.

Sources checked on 17 October 2026.

What are annonacin and the annonaceous acetogenins?

Long-chain fatty-acid derivatives made by the custard-apple family and almost nothing else, present throughout the soursop tree, fruit and leaves included; annonacin is the major one, and seed extract is the most toxic part in cell tests, which is why the seeds are never eaten.^{9, 10, 15} They dissolve in fat rather than water and survive boiling and bottling: they have been measured in leaf decoctions and in nectar.¹³ Part by part: soursop fruit vs soursop leaves.

How does annonacin damage nerve cells?

By starving them of energy. In cultured rat midbrain neurons, purified annonacin killed dopamine-producing cells at nanomolar concentrations by inhibiting complex I.⁷ In striatal neurons, ATP fell with the dose, the protein tau moved from the axons into the cell body, and the cells died; antioxidants did not help, restoring energy production did, which pins the damage on complex I.⁸ Tau is the protein that accumulates in progressive supranuclear palsy, the disease the Guadeloupe cases most resemble.

What happened in animals?

Rats given annonacin into a vein at 3.8 and 7.6 mg per kg per day for 28 days: the compound entered the brain, brain ATP fell by 44% and dopamine neurons in the substantia nigra fell by 31.7%, "in the absence of evident systemic toxicity".¹⁰ The obvious objection is the needle: nobody injects soursop, and oral bioavailability in rats was only 3.2% of a single dose.¹¹ The study that meets the objection ran for 12 months: mice drank a commercially available soursop juice (annonacin 16.2 mg per litre) in place of water, and phosphorylated tau accumulated in neurons in several brain regions, including in ordinary mice: the "first experimental evidence that long-lasting oral ingestion" of a widely consumed food can induce tau accumulation.¹²

What did the Caribbean studies find?

The limits travel with the findings: recalled exposure, wide confidence intervals, one referral centre in the early work, and in 2026 near-universal exposure in one group, so region cannot be separated from fruit. What the studies show is a consistent association across three territories, a dose effect and a severity effect in ordinary Parkinson's disease. What they cannot show is cause. The research group's phrase is "a probable etiological factor"; the agencies' is that a link is not established.^{15, 16}

How much annonacin is in soursop?

In the one published set of measurements, an average fruit contained about 15 mg of annonacin, a can of commercial nectar 36 mg, and a cup of leaf infusion or decoction 140 micrograms; one fruit or can a day for a year, the authors estimated, approaches the dose that caused the rat lesions.¹³ Seven fruits analysed in 2017 ranged from 14 to 226 micromoles of acetogenins per 100 g of pulp, a sixteen-fold spread, so no single per-fruit figure is reliable.¹⁴ No UK capsule, tea bag or bitters discloses an annonacin amount: see the graviola label guide.

Association or cause? What the agencies concluded

The French food safety agency (AFSSA, now ANSES) published its opinion on 28 April 2010. The animal data demonstrate neurotoxicity, it said, but on the evidence available "il n'est pas possible d'affirmer que les cas de syndromes parkinsoniens atypiques observés en Guadeloupe sont liés à la consommation d'Annonaceae": it is not possible to state that the Guadeloupe cases are linked to Annonaceae consumption. No quantitative recommendation could be proposed, but soursop preparations deserved particular attention.¹⁶ The EU-FORA report, written by three scientists at the German Federal Institute for Risk Assessment and approved on 7 September 2020 (an EFSA-hosted technical report, not a Panel opinion), found that "substantial uncertainties exist regarding the safe use of A. muricata-based supplements" and that the paucity of long-term studies "does not allow the establishment of a safe intake level".¹⁶ Cancer Research UK's page, last reviewed 21 October 2022, puts it plainly: "It may cause nerve changes and movement disorders."¹⁷

Is this relevant in the UK?

Nobody has measured it. A 2000 review from a London neurology department reported a three- to fourfold excess of sporadic atypical parkinsonism among UK patients of Afro-Caribbean and Indian origin; it did not measure soursop, and no UK study since has, so it is context rather than a finding.¹⁸ Soursop is a familiar fruit in many British Caribbean and West African households, and the leaf is now sold widely as tea bags, capsules and bitters, mostly without a neurological warning.

Who should be careful with soursop?

Anyone with Parkinson's disease or another neurological condition, anyone pregnant or breastfeeding, anyone taking medicines for blood pressure or diabetes, and anyone having cancer treatment should talk to their GP, pharmacist or specialist team before taking soursop leaf, tea, capsules, extracts or bitters. Medicines and pregnancy: soursop side effects. The everyday cup: is soursop tea safe to drink every day.

What we don't know

• Dose-response in people: the only exposure data are recalled fruit-years; no threshold exists.
• UK exposure. No consumption survey includes soursop and no UK product discloses its acetogenin content.
• Whether tea matters as much as fruit. A cup carries roughly a hundredth of a fruit's annonacin, yet any herbal tea was associated with the severe cluster in 2022.^{3, 13}

Frequently asked questions

Is soursop linked to Parkinson's disease?

By association: to an atypical, levodopa-resistant parkinsonism in the French Caribbean, and since 2026 to more severe Parkinson's disease in exposed patients.^{1, 2, 3, 6} Cause has not been shown.

Can soursop cause nerve damage?

Annonacin damages nerve cells in culture, rats and mice by a known mechanism.^{7, 10, 12} Whether ordinary human intakes do the same is not established, and no agency has set an amount below which it does not.¹⁶

Should people with Parkinson's avoid soursop?

Ask the neurologist, taking this page. The NHS advises checking with a pharmacist before taking any herbal product alongside medicines.^{3, 6, 17}

Sources

1. Caparros-Lefebvre D, Elbaz A. Case-control study, 87 patients, Guadeloupe. Lancet, 1999. PubMed 10440304.
2. Lannuzel A, et al. Atypical parkinsonism in Guadeloupe. Cross-sectional study, 160 patients; non-commercial funding. Brain, 2007. PubMed 17303592.
3. Cleret de Langavant L, et al. Annonaceae consumption and severity in degenerative parkinsonism. Observational, 180 patients; non-commercial funding. Movement Disorders, 2022. PubMed 36210778.
4. Nasri A, et al. Atypical parkinsonian syndromes in French Guiana. Cohort comparison, 372 patients. Journal of Parkinson's Disease, 2025. PubMed 40961237.
5. González-Lizárraga F, et al. Protein coaggregation in Caribbean atypical parkinsonism. Post-mortem series, 8 brains. Neuropathology and Applied Neurobiology, 2025. PubMed 40702589.
6. Ribeyron L, et al. Annonaceae fruit and Caribbean Parkinson's disease severity. Multicentre comparison, 74 and 104 patients. Behavioural Neurology, 2026. PubMed 42192274.
7. Lannuzel A, et al. Annonacin is toxic to dopaminergic neurons by impairment of energy metabolism. Cell culture. Neuroscience, 2003. PubMed 14521988.
8. Escobar-Khondiker M, et al. Annonacin causes tau pathology in cultured neurons. Journal of Neuroscience, 2007. PubMed 17634376; Höllerhage M, et al. Screen of 24 complex I inhibitors in cell culture. Experimental Neurology, 2009. PubMed 19682988.
9. Höllerhage M, et al. Neurotoxicity of dietary supplements from Annonaceae species. Cell culture; two authors at the US FDA. International Journal of Toxicology, 2015. PubMed 26405269.
10. Champy P, et al. Annonacin induces nigral and striatal neurodegeneration in rats. 28 days intravenous. Journal of Neurochemistry, 2004. PubMed 14675150.
11. Bonneau N, et al. Annonacin pharmacokinetics. Single oral dose in rats. Journal of Chromatography B, 2015. PubMed 26444335.
12. Rottscholl R, et al. Chronic consumption of Annona muricata juice and tau phosphorylation in mice. 12 months oral; non-commercial funding. Journal of Neurochemistry, 2016. PubMed 27569447.
13. Champy P, et al. Quantification of acetogenins in Annona muricata. Chemical analysis of fruit, nectar and leaf preparations. Movement Disorders, 2005. PubMed 16078200.
14. Bonneau N, et al. qNMR quantification of acetogenins in fruit pulp. Seven fruits. Phytochemical Analysis, 2017. PubMed 28092423.
15. Lannuzel A, Ruberg M, Michel PP. Etiological role of annonacin in Guadeloupe. Narrative review. Movement Disorders, 2008. PubMed 18816693.
16. Agency assessments. AFSSA (now ANSES). Avis relatif aux risques liés à la consommation de corossol et de ses préparations, saisine 2008-SA-0171, 28 April 2010 (French). anses.fr. Raclariu-Manolica AC, Bakhiya N, Hirsch-Ernst KI. Risk assessment regarding the use of Annona muricata in food supplements. EU-FORA technical report, approved 7 September 2020; EFSA fellowship funding. EFSA Journal, 2020. doi.org.
17. Cancer Research UK. Graviola (soursop). Last reviewed 21 October 2022. cancerresearchuk.org; NHS. Herbal medicines and complementary therapies. Reviewed 1 May 2026. nhs.uk.
18. Chaudhuri KR, Hu MT, Brooks DJ. Atypical parkinsonism in Afro-Caribbean and Indian origin immigrants to the UK. Review; no soursop exposure measured. Movement Disorders, 2000. PubMed 10634237.

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