Preparation method and stability of ellagic acid-rich pomegranate fruit peel extract

Abstract

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.

Bioactive components of pomegranate fruit and their transformation by fermentation processes

“…It was shown that a 4-month storage of ellagic acid extract from pomegranate rind at access to light caused no changes in color or clarity of the extract. Ellagic acid shows high stability within a wide range of temperatures; its melting point is 350 °C [22,28]. Similarly, a 4-month storage of the extract at 45 °C and 75 % humidity caused no changes, and no changes were observed during 4-month storage of this extract at 4 and 30 °C.…”

“…Ellagic acid is not produced on a commercial scale due to high costs of this process. Research is being conducted on its microbiological production using the Aspergillus Niger GH1 strain [4,26,28].…”

“…It was also shown that storage of extracts at these pH values caused a marked change in the contents of this compound after a period of 4 weeks. Reduction in its concentration may be explained by hydrolysis of the ester group of ellagic acid to hexahydroxydiphenolic acid [28].…”

Cardioprotective effect of whole fruit extract of pomegranate on doxorubicin-induced toxicity in rat

“…The total phenolics content was 157 ± 6.3 mg gallic acid equivalent/g of WFEP by Folin-Ciocalteu method. In an earlier report by Panichayupakaranant et al (2010) the method for preparation of pomegranate peel extract rich in ellagic acid has been described. The ellagic acid content of extract was increased from 7.06 to 13.63% w/w by partitioning of pomegranate peel extract between ethyl acetate and 2% aqueous acetic acid.…”

Photoprotection by Punica granatum seed oil nanoemulsion entrapping polyphenol-rich ethyl acetate fraction against UVB-induced DNA damage in human keratinocyte (HaCaT) cell line

“…The polyphenol-rich ethyl acetate fraction (EAF) from Punica granatum peel extract was obtained following the method described by [13] with some modifications.…”