Review Received: 2 December 2013 Revised: 1 July 2014 Accepted article published: 22 July 2014 Published online in Wiley Online Library: (wileyonlinelibrary.com) DOI 10.1002/jsfa.6833 Phytosterols and their extraction from various plant matrices using supercritical carbon dioxide: a review Md. Salim Uddin, a,b Md. Zaidul Islam Sarker, a* Sahena Ferdosh, c Md. Jahurul Haque Akanda, d Mst. Sabina Easmin, a Siti Hadijah Bt Shamsudin a and Kamaruzzaman Bin Yunus e Abstract Phytosterols provide important health benefits: in particular, the lowering of cholesterol. From environmental and commercial points of view, the most appropriate technique has been searched for extracting phytosterols from plant matrices. As a green technology, supercritical fluid extraction (SFE) using carbon dioxide (CO 2 ) is widely used to extract bioactive compounds from different plant matrices. Several studies have been performed to extract phytosterols using supercritical CO 2 (SC-CO 2 ) and this technology has clearly offered potential advantages over conventional extraction methods. However, the efficiency of SFE technology fully relies on the processing parameters, chemistry of interest compounds, nature of the plant matrices and expertise of handling. This review covers SFE technology with particular reference to phytosterol extraction using SC-CO 2 . Moreover, the chemistry of phytosterols, properties of supercritical fluids (SFs) and the applied experimental designs have been discussed for better understanding of phytosterol solubility in SC-CO 2 . © 2014 Society of Chemical Industry Keywords: bioactive compounds; phytosterols; supercritical carbon dioxide extraction; benefit of phytosterols INTRODUCTION A broad range of bioactive compounds such as phytochemicals, pharmaceutics, flavors, fragrances and pigments originate from plants. Natural bioactive compounds have diversified structures and functionalities that provide excellent molecular proper- ties for the production of nutraceuticals, functional foods and food additives. 1 Over the last few decades, natural bioactive compounds with potential for the treatment and prevention of human diseases have attracted much attention in many labora- tories and industries. Bioactive compounds are used as natural product-derived therapeutic agents or as disease-preventing nutrients. 2 Therefore, the growing market in functional foods and nutraceuticals is targeting all types of bioactive compounds, including lipids, carotenoids, phenolic compounds and plant sterols, for their health benefits. Plant sterols, known generally as phytosterols, are essential components of the membrane lipid bilayer 3,4 and are found in all plant tissues and especially in seeds, vegetables and cereals. 5 They perform functions in plants similar to those of cholesterol in animals and as precursors of important biomolecules such as sex hormones and vitamins. 6 In particular, phytosterols have received much attention owing to their capa- bility to lower serum cholesterol levels in humans, 7,8 resulting in significant reductions in the risk of heart disease. Moreover, they show anti-inflammatory, antibacterial, anti-ulcerative and antitumor properties, 9 and therefore make a great contribution to the value of natural products as medicinally active nutraceuticals. Conventional methods for lipid extraction from natural sources involve cooking, pressing and liquid extraction. The most common conventional process for extraction is liquid sol- vent extraction using chloroform, hexane, toluene, petroleum ether, acetone etc. 10 Extraction and isolation from several natural sources using liquid solvent produce large quantity of waste organic solvents that are harmful to human health as well as the environment. 11 Moreover, thermolabile com- pounds may be degraded in conventional separation methods due to applying high temperature for processing or evapo- rating organic solvents. Nowadays, people are concerned by the health, environmental and safety hazards associated with the use of organic solvents in food and pharmaceutical ∗ Correspondence to: Md Zaidul Islam Sarker, Department of Pharmaceu- tical Technology, Kulliyyah of Pharmacy, International IslamicUniversity Malaysia, Kuantan Campus, 25200 Kuantan, Pahang, Malaysia. E-mail: zaidul@iium.edu.my a Kulliyyah of Pharmacy, International Islamic University Malaysia, Kuantan Campus, 25200 Kuantan, Pahang, Malaysia b Department of Biochemistry and Molecular Biology, University of Rajshahi, Rajshahi 6205, Bangladesh c School of Industrial Technology, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia d Department of Food Science and Nutrition, Faculty of Applied Sciences, UCSI University, 56000 Kuala Lumpur, Malaysia e Kulliyyah of Science, International Islamic University Malaysia, Kuantan Cam- pus, 25200, Kuantan, Pahang, Malaysia J Sci Food Agric (2014) www.soci.org © 2014 Society of Chemical Industry