Plums etc do not have acetogenins. Pawpaws have acetogenins. That’s a fact. The primary acetogenin in pawpaws is annonacin. That’s another fact. Annonacin is toxic to cortical neurons. Another fact. Here’s a discussion of annonacin in Annona muricata -
"Both alkaloids and annonacin, the most abundant acetogenin, were toxic in vitro to dopaminergic and other neurons. However we have focused our work on annonacin for two reasons: (1) annonacin was toxic in nanomolar concentrations, whereas micromolar concentrations of the alkaloids were needed, (2) acetogenins are potent mitochondrial poisons, like other parkinsonism-inducing compounds. We have also shown that high concentrations of annonacin are present in the fruit or aqueous extracts of the leaves of A. muricata, can cross the blood brain barrier since it was detected in brain parenchyma of rats treated chronically with the molecule, and induced neurodegeneration of basal ganglia in these animals, similar to that observed in atypical parkinsonism. These studies reinforce the concept that consumption of Annonaceae may contribute to the pathogenesis of atypical parkinsonism in Guadeloupe."
And here are the results of a study on annonacin in pawpaws-
The average concentration of annonacin in the fruit pulp was 0.0701±0.0305mg/g. Purified annonacin (30.07μg/ml) and crude EtOAc extract (47.96μg/ml) induced 50% death of cortical neurons 48h post treatment. Annonacin toxicity was enhanced in the presence of crude extract.
Pawpaw fruit contains a high concentration of annonacin, which is toxic to cortical neurons. Crude fruit extract also induced neurotoxicity, highlighting the need for additional studies to determine the potential risks of neurodegeneration associated with chronic exposure to pawpaw products."