Estabilidade de L-(+)-Bornesitol, marcador químico de Hancornia speciosa Gomes, frente a diferentes condições de estresse.

Abstract

Hancornia speciosa Gomes, a plant species popularly known as ―mangaba‖, had its potential antihypertensive activity previously demonstrated by our research group, being the activity ascribed to polyphenols and cyclitols like L- (+)-bornesitol. The goal of this work was to evaluate the stability of the chemical marker bornesitol submitted to different stress conditions, namely acidic, alkaline and neutral hydrolysis, oxidative degradation, photolysis, thermal degradation and metal ion degradation. An extract of H. speciosa leaves was obtained by percolation with methanol/ethyl acetate (1:1) and its fractionation afforded bornesitol (1.45% w/w). To evaluate bornesitol stability, an UPLCMS/MS method was developed based on the MRM (Multiple Reaction Monitoring) acquisition mode and negative ionization mode, employing a specific (m/z 193 →161 Da) and a confirmatory transition (m/z 193 →175). The method was validated and showed adequate linearity (r 2 > 0.99), selectivity, specificity and precision (RSD < 2.9%). It was not possible to evaluate method accuracy by recovery studies. The method was robust for deliberate variations on dessolvation temperature (440 and 460 °C), but not for changes in the flow rate (90.24 and 0.36 mL/min) and dessolvation gas (840 and 960 L/h). During method development, the bornesitol signal was suppressed by the sodium chloride found in the matrix, which was eliminated by sample extraction with pyridine. The results from the stability studies, based on quantitation of bornesitol content (% ± s.d. w/w), allowed us to classify it as labile for acidic (71.96 ± 96%) and alkaline hydrolysis (77.37 ± 6.74%), whereas under oxidative and neutral hydrolysis conditions, bornesitol was regarded as very stable (90.09 ± 0.56% and 74.97 ± 0.52%, respectively). In the photolysis degradation, the cyclitol was classified as practically stable (98.78 ± 1.5%). A considerable reduction in bornesitol contents was induced by metal ions (34.67 ± 3.67%) and thermolysis (79.70 ± 1.13%). The present work furnished new data on bornesitol stability under different stress conditions, which might be relevant for the development and quality control of derivatives from H. speciosa leaves.