CALYSTEGINES, POLYHYDROXYLATED ALCALOIDS PRESENT IN VEGETABLES: FRUITS AND TUBERS

Calystegines are nortropane alkaloids with three to five hydroxyl groups. These alkaloids are recognized as glycosidase inhibitors and thus may have therapeutic potential to be exploited. There are also reports of its possible toxic effects when they are present in foods. Commercial cultivars of human consumption in Brazil have been analyzed for calystegines content. Samples of Solanum tuberosum L. (potato), Ipomoea batatas L. (sweet potato), Solanum lycopersicum (tomato), Solanum melongena (eggplant) and Solanum aethiopicum L. (gilo) were obtained from local markets in Rio de Janeiro, RJ, Brazil. Qualitative analyzes were performed by gas chromatography coupled to mass spectrometry (GC/MS) and high performance liquid chromatography coupled to mass spectrometry (LC/MS). Gas chromatography with flame ionization detector (GC/FID) was used in quantitative analysis. Five calystegines (A3, B1, B2, B4 and C1) were detected in the whole sample set and the amounts of three of them were determined: A3 (1.94-15.88 mg kg-1); B2 (7.59-23.7 mg kg-1) and B4 (3.61-9.38 mg kg-1). This is the first report on the occurrence of these alkaloids in Solanum aethiopicum L.