Department of Pharmacognosy and Pharmaceutical Botany, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Hat-Yai, Songkhla, Thailand.
Pharm Biol. 2010 Feb;48(2):201-5. doi: 10.3109/13880200903078503.
A simple one-step purification using liquid-liquid extraction for preparing pomegranate peel extract rich in ellagic acid has been demonstrated. The method involved partitioning of the 10% v/v water in methanol extract of pomegranate peel between ethyl acetate and 2% aqueous acetic acid. This method was capable of increasing the ellagic acid content of the extract from 7.06% to 13.63% w/w. Moreover, the antioxidant activity of the extract evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay was also increased (ED(50) from 38.21 to 14.91 micro/mL). Stability evaluations of the ellagic acid-rich pomegranate peel extract in several conditions through a period of four months found that the extracts were stable either kept under light or protected from light. The extracts were also stable under 4 degrees +/- 2 degrees C, 30 degrees +/- 2 degrees C and accelerated conditions at 45 degrees C with 75% relative humidity. However, study on the effect of pH on stability of the extract in the form of solution revealed that the extract was not stable in all tested pH (5.5, 7 and 8). These results indicated that the ellagic acid-rich pomegranate peel extract was stable when it was kept as dried powder, but it was not stable in any aqueous solution.
已证明，采用液-液萃取法可一步简单地从石榴皮 10%（v/v）甲醇提取物中分离出富含鞣花酸的石榴皮提取物。该方法可将提取物中鞣花酸的含量从 7.06%提高到 13.63%（w/w）。此外，通过 1,1-二苯基-2-苦基肼（DPPH）自由基清除试验评估提取物的抗氧化活性也有所提高（ED（50）从 38.21 微升至 14.91 微升）。通过四个月的时间，在几种条件下对富含鞣花酸的石榴皮提取物的稳定性进行评估发现，无论是在光照下还是避光下保存，提取物都很稳定。提取物在 4 摄氏度 +/- 2 摄氏度、30 摄氏度 +/- 2 摄氏度和 45 摄氏度、75%相对湿度的加速条件下也很稳定。然而，以溶液形式研究 pH 值对提取物稳定性的影响时发现，该提取物在所有测试的 pH 值（5.5、7 和 8）下均不稳定。这些结果表明，鞣花酸丰富的石榴皮提取物以干粉形式保存时稳定，但在任何水溶液中均不稳定。
