Extraction of phytochemicals from the pomegranate (Punica granatum L., Punicaceae) by reverse iontophoresis.

Plant metabolic profiling can provide a wealth of information regarding the biochemical status of the organism, but sample acquisition typically requires an invasive and/or destructive extraction process. Reverse iontophoresis (RI) imposes a small electric field across a biological membrane to substantially enhance the transport of charged and polar compounds and has been employed, in particular, to extract biomarkers of interest across human skin. The objective of this work was to examine the capability of RI to sample phytochemicals in a minimally invasive fashion in fructo (i.e., from the intact fruit). RI was principally used to extract a model, bioactive compound - specifically, ellagic acid - from the fruit peel of Punica granatum L. The RI sampling protocol was refined using isolated peel, and a number of experimental factors were examined and optimised, including preparation of the peel samples, the current intensity applied and the pH of the medium into which samples were collected. The most favourable conditions (3 mA current for a period of 1 hour, into a buffer at pH 7.4) were then applied to the successful RI extraction of ellagic acid from intact pomegranates. Multiple additional phytochemicals were also extracted and identified by liquid chromatography with tandem mass spectrometry (LC-MS/MS). A successful proof-of-concept has been achieved, demonstrating the capability to non-destructively extract phytochemicals of interest from intact fruit.

Phenolic glucosides from Flacourtia indica.

A new phenolic glucoside, (rel)-2-(4',6' -dibenzoyl-beta-glucopyranosyloxy)-7-(1alpha-hydroxy-2alpha-ethoxy-6alpha-acetyloxy-3-oxocyclohex-4-enoyl)-benzyl alcohol (Flacourticin) (1) and the known, 2-(4',6'-dibenzoyl-beta-glucopyranosyl)-5-hydroxy benzyl alcohol (4'-benzoylpoliothrysoside) (2) together with the new, (2E)-heptyl-3-(3,4-dihydroxyphenyl) acrylate (3), (+)-catechin (4) and sitosterol-beta-D-glucoside were isolated from Flacourtia indica. Their structures were assigned on the basis of 1D, 2D-NMR and as well by analysis of the LC-ESIMS data. The isolated compounds (1-4) were evaluated for alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) radical scavenging activity, and 3 was found to be two-fold less potent, with an IC50 = 12.01 microg/mL, compared to the positive control, Rutin, (IC50 = 5.83 microg/mL).