The custard apple family hides a dark secret behind its sweet, tropical fruits.

Gardening · Published 3 October 2026 Swipe more like this →

In short: The Annonaceae family includes beloved fruits like soursop and cherimoya, but these plants harbor potent neurotoxins called acetogenins. While some species are prized for their timber or culinary uses, regular consumption of certain varieties has been linked to severe neurological conditions, including a specific form of atypical Parkinsonism.

The Annonaceae, or custard apple family, is a massive group of flowering plants comprising about 2,400 species across 108 genera. Primarily tropical, they range from trees and shrubs to lianas, with a single temperate genus, Asimina, found in the Eastern United States. Their evolutionary history is ancient; fossil evidence from Japan’s Late Cretaceous period suggests the family’s common ancestor existed at least 89 million years ago. Today, they are classified into four subfamilies—Anaxagoreoideae, Ambavioideae, Annonoideae, and Malmeoideae—with molecular and morphological data helping refine their complex taxonomy.

Beyond their botanical diversity, these plants are biologically potent. Many species, including soursop (Annona muricata), contain acetogenins, compounds that inhibit NADH dehydrogenase and disrupt mitochondrial function. These substances are neurotoxins that cause a tauopathy, a condition marked by the accumulation of tau protein in the brain. Research suggests these toxins are the primary cause of atypical Parkinsonism in regions like Guadeloupe, where they may account for up to 70% of Parkinsonian cases. The effect is cumulative; daily consumption over a year is considered as damaging as eating the fruit once every ten days for a decade.

Despite these risks, the family remains economically and culturally significant. Fruits like the cherimoya, sweetsop, and atemoya are widely consumed, while the sacred earflower (Cymbopetalum penduliflorum) has historically flavored chocolate. Furthermore, the wood of the lancewood (Oxandra lanceolata) has long been valued for its toughness and elasticity, historically serving as a material for carriage shafts. While some researchers investigate the toxic properties of plants like the American pawpaw (Asimina triloba) for potential use in cancer treatments or as natural insecticides, the neurotoxic risks associated with the family’s most popular fruits serve as a sobering reminder of the chemical complexity found in nature.

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