β-Sitosterol: Supercritical Carbon Dioxide Extraction from Sea Buckthorn (Hippophae rhamnoides L.) Seeds

Marie Sajfrtová,Martina Wimmerová,Helena Sovová,Ivana Ličková,Zdeněk Wimmer

doi:10.3390/ijms11041842

Abstract

Supercritical fluid extraction represents an efficient and environmentally friendly technique for isolation of phytosterols from different plant sources. Sea buckthorn (Hippophae rhamnoides L.) seeds were extracted with supercritical carbon dioxide at pressures ranging from 15–60 MPa and temperatures of 40–80 °C. Oil and β-sitosterol yields were measured in the extraction course and compared with Soxhlet extraction with hexane. The average yield of β-sitosterol was 0.31 mg/g of seeds. The maximum concentration of β-sitosterol in the extract, 0.5% w/w, was achieved at 15 MPa, 40 °C, and a carbon dioxide consumption of 50 g/g of seeds. The extraction rate was maximal at 60 MPa and 40 °C. Both β-sitosterol yield and its concentration in the extract obtained with hexane were lower than with carbon dioxide.

Highlights

Plants are renewable sources of a large variety of natural products [1]
The Supercritical fluid extraction (SFE) conditions were optimized for the yield and the composition of extract from sea buckthorn seeds
The maximum extraction rate was at the maximum pressure used (60 MPa) at 40 °C

Summary

Introduction

Plants are renewable sources of a large variety of natural products [1]. A number of them have already been proved to display pharmacologically important features, and are used or considered for application in treatment of serious diseases [2]. Selection of a convenient isolation technology, as well as selection of an extraction solvent and the nature of the plant material used influence the product quality. Conventional methods of isolation of biologically active plant products from the natural sources are distillation, extraction, percolation or squeezing. Its principle consists of extraction of a natural material with a fluid existing in its supercritical state under defined conditions (temperature and pressure). Considering carbon dioxide as a most frequent supercritical solvent, it should be stated that due to its non-polar nature it is convenient for extracting vegetable oils, essential oils, sterols, some vitamins and other natural products present in plant oils. The extraction rate can be relatively controlled by changing temperature and pressure in the extraction vessel; factors which influence the solvating power of supercritical carbon dioxide

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