Background: Medicinal phytochemicals have been used as dietary supplements in Asia
and Africa for thousands of years. Biologically active antioxidants are very diverse and low in their
chemical compositions thereby limiting their efficacies. The present study focuses on the enhanced
accumulation of closely related dietary antioxidants: shikimate, quinate, salicylate and tocopherol in
Phyla dulcis, the Central American herb known for its anti-inflammatory medicinal properties; but
its polyphenolic antioxidants had not been studied.
Methods: Phyla dulcis stem cuttings were planted in the greenhouse, and in field plots and treated
with solutions of stoichiometric mixes of mineral salts known to double crop biomass and yield.
Controls were treated with water. At maturity, P. dulcis shoots and flowers were harvested per
treatment, immediately frozen in liquid nitrogen, and submitted to metabolomic analyses by gas
chromatography-time-of-flight mass spectrometry.
Results: Field plot P. dulcis treated with KKS-mineral salts combination induced increased shikimate
accumulation of 1.59 g per 100 g from the 0.799 g per 100 g in the untreated control. Similarly
salicylate, quinate, and tocopherols increased in accumulation by many orders of magnitude in the
stoichiometric mixes of mineral salts-treated P. dulcis compared with the untreated controls.
Conclusion: The accumulated polyphenolic antioxidants permitted the deduction of the unique biosynthetic
pathway of the shikimate, with a massive inhibition at the enzyme steps of dehydroquinate
dehydratase and shikimate dehydrogenase.