Non-destructive, reverse iontophoretic extraction of phytochemicals from Mangifera indica, Centella asiatica, Punica granatum, and Citrus sinensis

For the commercial-scale isolation of phytochemicals, a suitable plant biomass source (including species, origin, growing season, etc.) must be identified, and frequent analytical verification is required to ensure that the phytochemicals are present at predefined minimum threshold concentrations. While the latter are typically assessed in the laboratory, a more efficient and less resource-intensive approach would involve non-destructive and environmentally friendly measurements in situ. Reverse iontophoretic (RI) sampling offers a potential solution to this challenge. Objective: We aimed to demonstrate the non-destructive, RI sampling of phytochemicals of interest from biomass from four different sources. Materials and methods: RI experiments were performed in side-by-side diffusion cells using a current density of 0.5 mA/cm ², for a predetermined time in a defined pH environment, using (1) fresh leaves from Mangifera indica and Centella asiatica and (2) isolated peel from Punica granatum and Citrus sinensis. Results: Mangiferin, madecassoside, punicalagin, ellagic acid, and hesperidin were extracted from the different biomasses by RI. The amounts extracted ranged from 0.03 mg/100 mg of biomass for the cathodal extraction of madecassoside to 0.63 mg/100 mg of biomass for the anodal extraction of punicalagin. A linear relationship (r ² = 0.73) between the RI-extracted quantities of punicalagin and those determined using conventional methods was demonstrated. Conclusion: The non-destructive, in situ measurement of phytochemical levels by RI represents a feasible approach for timing the harvesting process.