Preparation and characterization of nanoemulsion prepared and loaded with Hypericum perforatum extract (St. John’s Wort)

Abstract

Background: Nanoemulsions, also known as nanometric-sized emulsions, are fine water-in-oil (w/o) and oil-in-water (o/w) dispersions of two immiscible fluids, as opposed to the milky-white hue concomitant with coarse dispersion. The current study aimed to prepare and characterize a noanoemulsion loaded with Hypericum perforatum extract using different phytochemical techniques. Also evaluate the effect of nanoformulation on particle size distribution, physical properties, and herbal extract stability.

Methods: Dried Hypericum perforatum (St. John's Wort) plants were obtained and extracted and studied its phytochemical compounds were studied by using High – Performance Liquid Chromatography (HPLC), then the nanoemulsion of Hypericum perforatum was prepared. The Characterization of nano emulsion and plant extract was performed by using X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR) and Surface Potential Analysis (Zeta Potential Analysis).

Results: Zeta potential values obtained were −1.3, −1, and −1.1 mV. The FTIR examination of the nanoemulsion showed multiple absorption peaks, indicating functional groups and bioactive chemicals. A board peak (3390 cm-1) indicates (O-H) stretching vibrations, confirming phenolic compounds and alcohol groups. Peaks at 2924 and 2857 cm-1 from (C-H) stretching of aliphatic chains showed lipids in nanoemulsion. Esters from fatty acids were confirmed by significant absorption bands at 1734cm-1, indicating C-O stretching. Peaks at 1647cm-1 (C-C stretching of aromatic compounds), 1400-1500cm-1 (aromatic rings), and 1100-1040cm-1 (alcohol and ether C-O stretching) were also examined. Examination using the transmission electron microscope showed that the nanoparticles emulsion formed from the plant extract ranged in diameter from 100–200 nm and were of a regular spherical shape. X-ray diffraction analysis of the nanoemulsion showed distinct peaks at 2θ angles ≈ 22.9° with d- spacing of 3.87°. Infrared spectra analysis of Hypericum perforatum displayed several absorption peaks. The intense and broad band was 3500-3300 cm-1 which corresponds (O-H) stretching vibration and indicates phenolic and flavonoid compounds. The predominant constituent in the plant extract was hyperforin with (5.772 min) retention time and significant peaks (20003.378). The other component was hypericin which was investigated with retention time (8.988) and peak amount (1000.276); it was present in lower concentrations than hyperforin

Conclusion: The study synthesized and characterized successfully nanoemulsion loaded Hypericum perforatum extract. The nanoemulsion development was confirmed by several tests, SEM, XRD, FTIR and zeta potential which confirmed that nanoemulsion encapsulated with preserved bioactive compounds. The study concluded that nanoemulsion improved plant extract phytoconstituent stability, suggesting new herbal formulation and pharmacological application.