SUBCRITICAL WATER EXTRACTION OF ANTHRAQUINONES FROM HETEROPHYLLAE PUSTULATA HOOK F. (RUBIACEAE)

MARÍA FERNANDA BARRERA VÁZQUEZ; LAURA RAQUEL COMINI; RAQUEL MARTINI; JUAN MANUEL MILANESIO; SUSANA CAROLINA NÚÑEZ MONTOYA; SUSANA BOTTINI; JOSÉ LUIS CABRERA

Eindhoven

Simposio; 27th European Symposium on Applied Thermodynamics (ESAT 2014); 2014

Eindhoven University of Technology, Delft University of Technology, Petroleum Institute, Abu Dhabi, UAE

The vegetable Kingdom has been traditionally supplier of the pharmaceutical industry, since it offers the possibility to find new chemical compounds for drugs formulation, providing a wide range of biological and / or technological applications [1-3]. The chemical study of the Heterophyllaea pustulata Hook (Rubiáceas) vegetable species, with known phototoxic activity [4,5], was performed with the aim of finding metabolites with biological activity useful from the therapeutic applications [6]. Thus, anthraquinones (AQs) with an important anti-bacterial, anti-viral and anti-cancer activity [7-.10]) were isolated and identified from the aerial parts of this plant. This anthaquinone extract has as majority compound rubiadin, soranjidiol and rubiadin 1-methyl éther [7]. These compounds are usually extracted from vegetable matrix by Soxhlet technique performing successive extraction with solvents of increasing polarity, starting with hexane, following with benzene and finally ethyl acetate. However, this technique presents a low extraction yield of total AQs, high time-consuming and involves large solvent amount. In this work, the extraction of AQ from H. pustulata using subcritical water is evaluated as an alternative method. The effect of several variables on the AQ extraction yield is studied: temperature extraction (120, 170 and 220 oC), water flowrate (3, 5 and 7 ml/min) and pressure (45, 60 and 75 bar). The results show that the AQ extraction yield increases with temperature, reaching a maximum at 170 oC, decreasing at higher temperatures. This effect could be related to the thermal decomposition of AQs. At a given temperature of 170 oC, the AQ extraction yield increases with the water flowrate. The pressure extraction has no significative effect on the extraction yield. Within the experimental range studied, the optimum extraction conditions are 170 oC, 7 ml/min and 60 bar.