Untargeted metabolomic evaluation of the chemical composition of water and ethanol extracts in two species of Plectranthus

Abstract

In spite of the world-renowned Brazilian biodiversity and the therapeutic potential of its medicinal plants, lack of information regarding the variation in their chemical composition due to growth conditions is an obstacle to their use and quality control. In this project, the chemical composition and variability of the ethanol and water extracts of two species of Plectranthus, commonly known as boldo, will be studied. Both P. barbatus and P. neochilus are commonly cultivated in gardens and the fresh leaves are consumed in hot and cold beverages for digestive disorders. Therefore, a wide range of cultivation conditions are to be expected. Previously identified specimens of both species will be cultivated in the Institute of Biology, UNICAMP, and used to produce cuttings planted in 1 L pots. These plants wil be grown in a greenhouse subject to varied temperature, irrigation and light conditions. At the end of the treatment, samples of the leaves will be collected, immediately frozen in liquid nitrogen and lyophilized. The material will be ground and extracted with water (mimicking tea) or ethanol in an ultrasonic bath. The extracts will be analyzed by LC-MS and the chromatograms will be compared using an untargeted metabolomics approach to determine the main components of the extracts of each species and to observe how the cultivation conditions affect their composition. Compound identification will be carried out by comparison of exact mass, elemental composition determination and tandem mass mass spectra with chemical and mass spectra databases and as well as information from literature. The chemical profile of water and ethanol extracts of P. barbatus and P. neochilus will be based on the analysis of over one hundred individual extractions, of plants cultivated under diverse conditions, resulting in a robust evaluation of their overall composition, and will be used for subsequent studies of their therapeutic activity. The results will give socially relevant information, as the fresh medicinal plants are popularly used without a complete knowledge of their composition. Furthermore, the results will indicate the best growth and harvest conditions for these species and set the basis for the quality control of fresh and dry plants, extracts and phytotherapic medicine.