Unveiling antioxidant capacity of standardized chitosan-tripolyphosphate microcapsules containing polyphenol-rich extract of Portulaca oleraceae

Abstract

The medicinal plant Portulaca oleraceae has a long history of usage in traditional medicine. Plant extracts have several interesting pharmacological effects but have some drawbacks that can be addressed via capsulation with chitosan. This work set out to do just that tally up the antioxidant effects of a polyphenol-rich P. olerace extract and see how capsulation affected them. The reflux extraction and response surface methodology (RSM) were carried out to optimize the phenolic and flavonoid content of P. oleraceae extract. Additionally, high-resolution mass spectrometry was employed to determine the secondary metabolite present in the extract. The microcapsules of extract-loaded chitosan were prepared using the ionic gelation method and characterized in terms of size, encapsulation efficiency (EE), and morphology of microcapsules. Fourier transform infrared (FTIR) was used to observe the successful production of microcapsules with a principal component analysis (PCA) approach. The antioxidant activity of microcapsules was established using the radical scavenging method. According to RSM, the highest amounts of TPC and TFC were obtained at 72.894 % ethanol, 2.031 h, and 57.384 °C. The compounds were employed from the optimized extract of P. oleraceae including phenolics and flavonoids. The microcapsules were secured with a %EE of 43.56 ± 2.31 %. The characteristics of microcapsules were approved for the obtained product's successful synthesis according to the PCA. The microcapsules have antioxidant activity in a concentration-dependent manner (p < 0.0001). The findings of this study underscored the benefits of employing chitosan as a nanocarrier for extract, offering a promising approach to enhance plant-derived therapies.

Keywords: Antioxidant activity; Ionic gelation; Portulaca olearacea; Response surface methodology.

Fig. 1

The three-dimensional (3D) response surface plots of P. oleraceae extraction for TPC (A) and TFC (B) for solvent concentration, temperature, and extraction time as a function of key interaction factors for RSM.

Fig. 2

The characteristic of P. oleraceae extract-chitosan microcapsule. Particle size analysis (A) and Morphological analysis using SEM with a magnification of 2500 (B).

Fig. 3

The FTIR spectrum of P. oleraceae extract, microcapsules, and chitosan in a wavenumber of 4000–500 cm⁻¹..

Fig. 4

The distribution of samples based on % transmittance in the wavenumber of fingerprint area. Chitosan (A), P. oleraceae extract (B), and Microcapsules (C).

Fig. 5

The antioxidant activity of P. oleracea extract and microcapsules against DPPH radical in a variation of concentrations. The result showed significant differences between extract and microcapsules using a t-test with p < 0.0001.