Study On Preparation And Antioxidant Activities Of Procyanidins From The Seedpod Of Nelumbo Nucifera Gaertn

Lianfang, which is recorded in the 2010 edition of Chinese Pharmacopoeia, is the dry receptacle of Nelumbo nucifera Gaertn. The research indicated that lotus seedpod was rich in procyanidins, which had attracted attention in the fields of pharmacology and food chemistry because of their beneficially pharmacological effects, including their protective action towards cardiovascular disease and the oxygen free radical scavenger capacities. Procyanidins have been widely applied as raw material, chemical additive, medicine healthy product, cosmetics and nutrition addition agent.In this paper, the relevance of content to growth period, rapid determination method of procyanidins, preparation and antioxidant activity of procyanidins were studied.The seedpods were collected from Hangzhou, Lishui and Quzhou between July to September to study the influences of different drying methods, grades of maturity, collecting times and production places on the contents of procyanidins and polyphenol. The results showed that different drying methods had influence on the contents of procyanidins and the apparent of lotus seedpod. The lotus seedpod should be dried in dryer or in a shady, avoid exposing to the sun. The maturity had great influence on the contents of procyanidins and polyphenol. The mature had much more procyanidins and polyphenol than the young, so mature seedpod should be collected. Although the contents of procyanidins and polyphenol had some changes with the time and the origin, there were no significant differences in the contents of procyanidins and phenols of lotus seedpod collected in different places and different times. Wide origin places have been demonstrated suitable to provide raw materials for industrial production. And lotus seedpod collection was appropriate from the middle of July to September. The contents of procyanidins changed in variation range of 6% to 8%, while the contents of polyphenol changed between 9% and 11%.A method for rapid determination of proanthocyanidins and total phenolics in the seedpod of Nelumbo nucifera Gaertn by Near Infrared Diffuse Reflectance Spectroscopy has been developed. Calibration models were established using the PLS (Partial Least Squares), while the contents of proanthocyanidins and total phenolics were measured by UV. The study showed that second derivative pretreatments and Savitzky-Golay smoothing filter methods could extract spectra information thoroughly. The correlation coefficient (r) of proanthocyanidins was 0.9621. The correlation coefficient (r) of total phenolics was 0.9254. Compared to the traditional colorimetric method the near infrared diffuse reflectance spectroscopy method could save much time. The near infrared diffuse reflectance spectroscopy method could be used to analyze the main active components in the seedpod rapidly and could also be used routinely in the traditional Chinese materia medica manufacturers for quality control of raw materials.A new extraction technology was used. The effect of extraction was optimized using orthogonal array experimental in water and ethanol respectively. The optimized process conditions by water were as follows:4h extracting time,30 min for time interval,100℃temperature and 18 mL/g solvent to seedpod ratio, the extraction transfer rate was 81.1%. Compared with conventional water extraction method, the solvent consumption decreased by 43%, while the extraction transfer rate increased by 4%. The optimized process conditions by ethanol were as follows:50%(Ⅴ/Ⅴ) ethanol, 2.5 h extracting time,30 min for time interval,12 mL/g solvent to seedpod ratio, and the extraction transfer rate was 91.1%. Compared with conventional ethanol extraction method, the solvent consumption decreased by 25%, extraction time reduced by 37.5%, while the extraction transfer rate increased by 4.4%. The new extraction technology saved in time, energy and solvent consumption, which was appropriate to industrial production.The crude extracts were purified by resin, and the method was as follows:the solution in 0.1-0.2 crude drug g/mL was added 4 BV (BV, bed volume) into resin column in the speed of 1.5 BV/h. Then,4 BV of water was added to wash away non-procyanidine in the speed of 4 BV/h.40% ethanol eluted 6 BV in 2 BV/h, and the eluate was dried in vacuum. The resin column was cleaned and reused. The product yield was 3.8%, the purity of procyanidins was over 80%.The antioxidant activities were compared among nine plants contained procyanidins, aiming to explore potential procyanidins resources. The free radical scavenging capacity and total reducing power were used as the index to determine antioxidant activity. The lotus seedpod, grape seeds, sanguisorba officinalis, lotus leaf and longan had stronger antioxidant activities. The antioxidant activities of the extracts of procyanidins from the five plants were compared. As a result, the lotus seedpod and sanguisorba officinalis had higher content of procyanidins, which could be used as raw materials for procyanidins.The antioxidant activities of procyanidins of different degrees of polymerization from grape seed and lotus seedpod were determined. The procyanidins from grape seed and lotus seedpod had stronger antioxidant activity than Vc in vitro. There was no great difference in antioxidant activity of two sources of procyanidins in the same mass concentration. Procyanidins, the average degree of polymerization was less than 5, showed difference in antioxidant activity with no significance.