Purported Erythroxylum coca var. ipadu Plowman (E. c. var. ipadu; Amazonian coca) leaves were harvested from fields in Colombia, South America (S. A.) during the months of October, November and December, 1997 to: (i) determine if their flavonoid profiles were complementary to those of our collection and (ii) determine if the leaf flavonoids could be indicative of kinship to a specific taxon(s) of cultivated Erythroxylum. Polar methanolic extracts from leaf tissue of Amazonian coca harvested from fields in Colombia S. A., were assayed by HPLC, GC-MS, LC-MS and 1H NMR to determine the flavonoid profile and O-conjugation of aglycones. These leaf extracts afforded eight O-conjugated flavonoids: two O-conjugates of taxifolin, one O-conjugate of quercetin, two, O-conjugates of eriodictyol three, O-conjugates of kaempferol. Present also in leaf tissue of Amazonian field grown E. c. var. ipadu, but lacking in leaf tissue from our collection was an O-ethyl ester typically found in E. c. var. coca, kaempferols and a O-7-rutinoside commonly encountered in the E. novogranatense taxons. Flavonoids in our collection of Amazonian coca, previously obtained from Colombia, S. A., contained five O-conjugated derivatives of taxifolin and an O-conjugated quercetin. Thus, the leaf flavonoids of the taxon differ not only between species but also within taxons. The flavonoids of E. c. var. ipadu (Amazonian coca) currently under cultivation in fields in Colombian are a mixture of those present in E. c. var. coca, E. c. var. ipadu and E. n. var. truxillense, whereas the flavonoids present in our living collection of E. c. var. ipadu are derivates of E. c. var. coca. Our data strongly suggest that Amazonian coca (E. c. var. ipadu) currently under cultivation in Colombian fields is a genetic hybrid between E. c. var. coca and E. n. var. truxillense. We propose that this hybridization occurred after the late 1970ís.

Key words: chemotaxonomic, Erythroxylum, flavonoids, hybridization