VARIATION OF PHENOLIC COMPOUNDS, FLAVONOIDS AND TANNINS IN Vanilla planifolia Jacks. ex Andrews IN THE HUASTECA HIDALGUENSE, MEXICO

Abstract

Phytochemicals or secondary metabolites can be bioactive compounds, with a low molecular weight, which generally protect the plant against pests, bacteria, environmental stress, UV radiation, or other factors. In vanilla (Vanilla planifolia Jacks. ex Andrews) compounds are synthesized that show microbial inhibition against phytopathogens; however, the type of phytochemicals in the vegetative structures of this species is scarcely known. Under the hypothesis that the type and concentration of phytochemicals varies according to the plant tissue and the site of plant collection, the objective of the study was to detect the type of phytochemicals and to quantify the concentration of total phenolic compounds (TPC), total tannins (TT), condensed tannins (CT) and flavonoids (Flav) in leaf, stem, flower and cured fruit (pod) from vanilla, from three sites (Huizotlaco, Coacuilco and Contepec) of the Huasteca Hidalguense in México. The different types of metabolites were identified in methanol, chloroform and hexane extracts through thin-layer chromatography (TLC). TPC, TT, CT and Flav were quantified in the methanol extracts of the four vegetative structures through spectrophotometric methods. TLC showed the presence of Flav, saponins and terpenoids. The pod presented the highest concentration of TPC (749.608 mg 100 g-1 ) and TT (102.141 mg 100 g-1 ), and the leaf had the highest concentration of Flav (127.023 mg 100 g-1 ) and condensed tannins (40.992 mg 100 g-1 ). Among the collection sites, Coacuilco stood out for the highest concentration of Flav and TT, and Contepec for the highest concentration of TPC and CT.