Development of bigels containing hedychium Coronarium Leaf Extract from high voltage pulsed electric field extraction for combating acne-related bacteria

Abstract

This study aimed to investigate the potential of Hedychium coronarium J. Koenig leaf and rhizomes extract as an active ingredient for antimicrobial properties, with a specific focus on anti-acne effects, and to incorporate the extract into bigel systems. The extracts of H. coronarium leaves and rhizomes were obtained through ethanolic extraction assisted by various pulse-electric field (PEF) treatments, including 10, 14, and 20 kV/cm. The chemical compositions of each extract were investigated by high-performance liquid chromatography. Each extract was assessed for its antimicrobial effects, focusing on acne treatment against Cutibacterium acnes, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, Micrococcus luteus, and Escherichia coli. The most effective extract was further incorporated into the bigels. Several aspects influencing bigel systems were investigated, including the type and amount of hydrogelators or organogelators, as well as the hydrogel-to-organogel ratio. Polyvinyl alcohol, hydroxyethyl cellulose, xanthan gum, and acacia gum were used as hydrogelators in the present study, whereas organogelators included polyethylene glycol 400, PEG 40 hydrogenated castor oil, sorbitan monostearate, and glyceryl monostearate. The bigels were characterized for their structure and molecule arrangement using X-ray diffraction analysis, the chemical interactions between the components of the bigels using Fourier-transform infrared spectroscopy, the texture properties using a texture analyzer, and the microstrural properties using scanning electron microscopy. The findings noted that H. coronarium leaf extract from 20 kV/cm-PEF extraction displayed the most powerful inhibitory activity against all microorganisms with the lowest minimum inhibitory concentrations (MICs) of 0.6, 1.3, and 0.6 µg/ml against C. acnes, S. aureus, and P. aeruginosa, respectively. Therefore, it was selected for further incorporation into the bigel system, of which the suitable system was developed using the combination of PVA and acacia gum. The bigel containing H. coronarium leaf extract was a flexible translucent gel patch with good stability under the heating and cooling conditions. Incorporating of the extract had no impact on the chemical and crystalline structure of the bigels. The bigels containing 0.15% w/w H. coronarium leaf extract, which was 1,000 times of its MICs against the acne-related bacteria, exhibited a tensile strength of 5.52 ± 0.58 kg/cm2, an elongation of 7.15 ± 0.00%, and a Young’s modulus of 0.76 ± 0.08 kPa, indicating strong resistance, durability, and excellent flexibility. In conclusion, the bigel incorporating H. coronarium leaf extract proved to be suitable for use as a patch, exhibiting favorable aesthetic qualities. Therefore, PEF extraction was proposed as an environmentally friendly extraction process that could improve the extraction yield, the content of the biologically active compounds, and the antimicrobial effects of H. coronarium leaf, which were attractive for the cosmetic industry.