NMR Analysis of Potentially Neurotoxic Annonaceous Fruits

Graviola (Annona muricata), atemoya (A. squamosa x A. cherimola), ata (A. squamosa) and biriba (Rollinia mucosa) lyophilized fruit pulps and atemoya seeds were extracted with methanol at 100 degrees C and 10.3 MPascal pressure using an Accelerated Solvent Extractor (ASE) and analyzed by NMR to see if they have the known toxicophores (an alpha,beta-unsaturated gamma-lactone and substituted tetrahydrofuran ring) that are in the neurotoxins annonacin and squamocin. The spectra of extracts from graviola, ata and biriba pulp and atemoya seeds showed the possible presence of relatively large amounts of these toxicophores. There was much less in the extracts of atemoya pulp. Thus, NMR analysis can be used to screen these fruits for the possible presence of the known toxicophores. Moreover, the methanol-soluble material in all four fruits showed the presence of glycosides as the major components.