Study On Extraction, Purification And Analysis Of Proanthocyanidins From Grape Seeds

Proanthocyanidins are polyphenols, which are widely used in field of medication, health care and food due to their biological activities such as scavenging free radical and antioxidation. Proanthocyanidins are widely distributed throughout the plant kingdom, especially grape seed.In this paper, reversed-phase high-performance liquid chromatography with electrospray ionization mass sepectrometry(RP-HPLC/ESI-MASS)is performed to analyze proanthocyanidins . Proanthocyanidins monomer and oligomers are identified according to the mass of the charged pseudomolecular ion[M-H]. Besides, the measurement of SOD-like activity of proanthocyanidins by using pyrogallol autooxidation is improved. The optimum conditions are determined as the follows: wavelength of measurement is 420nm, the buffer system is Tris-HAc, the concentration of pyrogallol is 10mmol/L, pH is 8.2, the concentration of Tris-HAc solution is 0.05 mmol/L.The main factors influencing extraction process, such as extraction and purification process are investigated. The optimum condition is determined as the follows: the extractant is 60% acetone aqueous solution, the ratio of solid material to solution is 1:10; and the extracting time is 24 hours at 40°C. By adding NaCl to the extractant, aqueous two phases could form, which is favourable for the extraction of proanthocyanidins. The novel extraction technique of aqueous two phase is firstly utilized in the purification of proanthocyanidins and good results are obtained.Product is obtained from acetone phase of extractant through the process , which consists ofmacropore resin absorption, concentration gradient dessorption with ethanol and extraction with ethyl acetate, high yield of 0.59% can be obtained, and the purity of product is more than 98%.