Chiang Mai Journal of Science

Fresh or dried fruit of  Terminalia chebula Retz. is commonly used as herbal medicine as it contains various phytochemicals including gallic acid (GA), ellagic acid (EA), and corilagin (CG). These polyphenolic compounds also exhibited therapeutic properties such as antioxidant, antihyperlipidemia and anticarcinogenic activities. This study investigated the separation of polyphenolic compounds such as gallic acid and ellagic acid from T. chebula fruits by subcritical water extraction (SWE). We considered the effect of  extraction temperature (120-220^oC) and water flow rates (2-4 ml/min) at the pressure of 4-6 MPa on the amount of compounds extracted and determine the suitable conditions for subcritical water extraction of  these compounds. The results showed that the amount of  GA and EA extracted increased when the extraction temperature increased and they were the highest at 180^oC beyond which the products decreased due to thermal degradation. At a fixed temperature of  180^oC, the effect of water flow rate on the amount of desirable compounds indicated that the increase in water flow rate gave higher amount of GA and EA extracted. The suitable condition for subcritical water extraction of gallic acid and ellagic acid from T. chebula fruits is at temperature of 180^oC and water flow rate of 4 ml/min.