Effects of salicylic acid on the production of polyphenols and the reducing power of Theobroma cacao calli

Abstract

• The role of salicylic acid in modulating the total polyphenol content and reducing power activity in undifferentiated Theobroma cacao calli was demonstrated. • Conditions that maximize polyphenol content and the iron reducing potential in undifferentiated callus extracts were determined to guide future research. • Mathematical models were developed for predicting total phenolic content and reducing power capacity. Cocoa ( Theobroma cacao ) contains high levels of phenolic compounds with pharmacologically interesting activities. Prior research has not sufficiently investigated obtaining these compounds through in vitro culture by using metabolic elicitation and quantifying polyphenols in undifferentiated cell biomass samples in this species. In vitro calli obtained from staminodes and petals were elicited with 0.01 and 0.1 mg L −1 salicylic acid (SA). Secondary metabolites were determined in the calli and their culture medium, from the immature and mature flowers, leaves, and fruits of field-grown plants. The most abundant compounds were free amino acids, alkaloids, reducing carbohydrates, phenols, pyrocatecholic tannins, and flavonoids. Resins, triterpenes, steroids, saponins, coumarins, and quinones were absent in the calli. A high concentration of total polyphenols (58.4 µg g −1 ) was obtained from staminode-derived calli elicited with 0.1 mg L −1 SA. With these conditions, the total polyphenol content was 40.22 µg g −1 greater than that in the control. In general, SA also stimulated the reducing power activity; a better value (5.87 µmol mL −1 Fe 2+ ) was obtained in callus extracts from petals with salicylic acid (0.1 mg L −1 ). This research was based on a full factorial study design with two levels, a method that allows the desired information to be obtained at the lowest possible cost.