phd rubner

Extraction of bioactive compounds from Phyllanthus amarus using pressurized fluids

Author: Rubner Gonçalves Pereira

The processes of development, production and use of natural products with bioactive properties have attracted attention in the food, pharmaceutical and cosmetic industries. Among these processes, the technology that uses pressurized fluids has been largerly studied. However, reports of the application for extraction from Phyllanthus amarus are rare, but it is necessary to obtain extracts free of toxic solvents (clean technology) and with a higher concentration of the bioactive compound (high selectivity) when compared to conventional techniques. Considering that lignans are the major bioactive compounds of this plant, this work had the objective of obtaining extracts rich in lignans from P. amarus using pressurized fluids as solvents. The proposal was to perform extractions: i. By Pressurized Liquid Extraction (PLE), using water and ethanol as solvents, evaluating the effect of temperature and comparing with a low-pressure extraction method (Ultra-Turrax Disperser Extraction - EUT); ii. Supercritical Fluid Extraction (SFE) using carbon dioxide as solvent (SFE1) and evaluating the effect of temperature, pressure, and the addition of cosolvent (SFE2). The analysis of Gas Chromatography - Mass Spectrometry was used to identify the compounds present in the extracts obtained by PLE and EUT. The quantification of phyllanthin and niranthin in the extracts was performed by High-Performance Liquid Chromatography with a Diode-Array Detector. The estimative of the Cost of Manufacturing (COM) were performed for the best extraction conditions. It was verified that ethanol 50% (v / v) was the best solvent to extract larger quantities of both lignans of the raw material, by the PLE and EUT methods. However, the use of absolute ethanol as solvent leads to extracts with higher concentrations of phyllanthin and niranthin. The temperature was not significant in PLE. In SFE processes, it was found that temperature and pressure are significant parameters for the extraction of lignans by SFE1 but not by SFE2. The use of cosolvents in SFE2 caused an increase of lignans obtained from raw material compared to SFE1 but decreased the selectivity of the process, since the concentration of lignans in the SFE2 extract was between 2.5 and 4.0% while it was 25 to 35% for SFE1. It was verified that the cost of the raw material represents more than 90% of the COM of the processes studied. The COM values of PLE and SFE2 were lower than that of SFE1. However, in the best SFE1 condition, the obtained extracts are 9 and 17 times richer than those obtained under the best conditions of SFE2 and PLE, respectively.