Abstract—Mangosteen pericarp has been used for long time as traditional medicine. One of main active ingredient in mangosteen pericarp is xanthone. Xanthone has remarkable effects on cardiovascular, antiviral, and anti-inflammatory. Subcritical ethanol extraction (Sc-ethanol) was employed to extract xanthone from dried mangosteen pericarp and compared with maceration and soxhlet extraction. The Sc-ethanol was applied by various temperature (80, 120 and 160 o C), ethanol concentration (50, 72.5 and 95%) and extraction time (10, 20 and 30 min.) for 1:20 of sample to solvent ratio. The Box-Behnken design was applied to investigate the optimum condition of Sc-ethanol extration. The optimum conditions from Box-Behnken design to obtain the highest xanthone were determined at the optimum conditions as following; temperature 160 o C, extraction time 30 min in 95% ethanol. The results presented that for maceration, soxhlet and Sc-ethanol extractions in 0.5 h, the extracted xanthones were 28.31, 31.26 and 57.42 mg/g of dried mangosteen pericarp respectively. Index Terms—Mangosteen pericarp, maceration, soxhlet, subcritical ethanol extraction, xanthone. I. INTRODUCTION Mangosteen (Garcinia mangostana Linn.) is in Guttiferae family that is tangerine-size and is deep purple in color on the outside, with a bright white pulp in the inside [1]. It is known as “The Queen of Fruits” because of its excellent flavor. It’s grown in Thailand and Southeast Asian countries. The fruit pericarp of this plant has been used for long time as a traditional medicine for treatment of abdominal pain, diarrhea, dysentery, infected wound, suppuration, and chronic ulcer [2]. Xanthone is the major active ingredient in mangosteen pericarp. The xanthone structure is a very interesting scaffold for different groups in different positions leading to a large variety of pharmacological activities. The xanthone derivative has a remarkable effect on antiulcerogenic [3], antifungal activity [4], antibacterial activity [5], [6], inhibitors of proteinkinase [7], anticancer activity [8], antioxidant [9], [10] and anti-inflammatory [11], [12]. Due to its pharmacological activities, it is popularly applied to herbal cosmetics and pharmaceutical products. There are mainly two ways to extract mangosteen pericarp. The first way is the tradition extraction techniques such as Manuscript received May 5, 2014; revised July 7, 2014. This work was supported in part by the Faculty of Engineering, Mahidol University, and The Government Pharmaceutical Organization (GPO), Bangkok, Thailand. N. Yoswathana and M. N. Eshtiaghi are with the Department of Chemical Engineering, Faculty of Engineering, Mahidol University, Salaya, Phuthamonthol ampur, Nakornprathom Province, Thailand 73170 (corresponding author: N. Yoswathana; e-mail: nuttawan.yos@mahidol.ac.th, mohamman.esh@ mahidol.ac.th). soxhlet extraction and maceration. The second way is novel extraction techniques such as ultrasonic assisted extraction and subcritical ethanol extraction. Soxhlet extraction has been used for a long time. During soxhlet extraction, fresh solvent can repeatedly bring to contact with sample many times and the system remains at a high temperature [13]. Maceration is very simple method that is just soaking material in solvent for long time. It has been developed for many applications such as food preparation, sewage treatment and winemaking process [14]. Subcritical fluid extraction is the method that using fluid under external pressurization above its boiling point such as 100 o C for water and 78.3 o C for ethanol. The most studied subcritical fluid extraction was subcritical water extraction (SCWE). Subcritical or superheated water extraction (SCWE) on essential oils is a new technique based on the use of water, at temperatures between 100 o C and 374 o C and pressure high enough to maintain the liquid state [15]. It is also called pressurized hot water extraction (PHWE) or pressurized low polarity water extraction (PLPWE). Under subcritical state, water is much less polar and organic compounds are much more soluble than at room temperature. The most important advantages of SCWE over traditional extraction techniques are shorter extraction time, higher quality of the extract, lower costs of the extracting agent, and an environmentally compatible technique [16]. The applications of subcritical water for extraction, it can be used to extract antioxidant compounds from rosemary plants [17] as well as to extract whitening agents and azo dyes in paper samples [18], anthocyanins from red grape skin [19]. Box-Behnken designs (BBK) are experimental designs and generally used to find response surface methodology. The BBK designs have advantages that reduce experiments due to it require only three levels and it is efficiency to prepare and explain when compare to the full factorial design and other methods [20]. The extraction methods were used to extract xanthone and alpha mangostin from mangosteen pericarp that were performed with soxhlet extraction, maceration and subcritical ethanol extraction for comparison of extracts from each methods. II. MATERIALS AND METHODS A. Materials Dried mangosteen (Garcinia mangostana Linn.) pericarps were obtained from Government Pharmaceutical Organization (GPO, Thailand). For lab study, the dried mangosteen pericarp was crushed by hammer and grounded with grinder (5657 HAAN, Retsch, GERMANY) to obtain 3 mm particle size. The dried mangosteen pericarp powder was Optimization of Subcritical Ethanol Extraction for Xanthone from Mangosteen Pericarp Nuttawan Yoswathana and M. N. Eshtiaghi International Journal of Chemical Engineering and Applications, Vol. 6, No. 2, April 2015 115 DOI: 10.7763/IJCEA.2015.V6.463