Development of a Sericin Hydrogel to Deliver Anthocyanins from Purple Waxy Corn Cob (Zea mays L.) Extract and In Vitro Evaluation of Anti-Inflammatory Effects.

Nattawadee Kanpipit,Suthasinee Thapphasaraphong,Aroonsri Priprem,Natsajee Nualkaew,Worawikunya Kiatponglarp

doi:10.3390/pharmaceutics14030577

Nattawadee Kanpipit, Suthasinee Thapphasaraphong + Show 3 more

Open Access

https://doi.org/10.3390/pharmaceutics14030577

Copy DOI

Abstract

Sericin-alginate hydrogel formulations with purple waxy corn (Zea mays L.) cob extract (PWCC) for topical anti-inflammatory application are developed and evaluated. The physical properties such as viscosity, pH, and anthocyanin release are examined and in vitro anti-inflammatory activities, such as NO inhibition and IL-6, IL-1β, TNF-α, iNOS, and COX-2 expression, are evaluated in LPS-stimulated RAW 264.7 murine macrophages. The sericin-alginate hydrogel is prepared by physical crosslinking through the ionic interaction of the polymers combined with anthocyanin from PWCC at pH 6.5. The hydrogel formulation with 2.00% w/v sericin, 0.20% w/v alginate, and 0.15% w/v PWCC (SN6) shows a suitable viscosity for topical treatment, the highest nitric oxide inhibition (79.43%), no cytotoxicity, and reduced expression of IL-6, IL-1β, and TNF-α mediators. Moreover, the SN6 formulation displays a sustained anthocyanin release over 8–12 h, which correlates with the Korsmeyer–Peppas model. The FT-IR spectrum of SN6 confirmed interaction of the sericin polymer with anthocyanins from PWCC via H-bonding by the shifted peak of amide I and amide III. In addition, the anthocyanin is stable in sericin hydrogels under heating-cooling storage conditions. Therefore, we suggest that this hydrogel formulation has potential as an anti-inflammatory agent. The formulation will be further investigated for in vivo studies and clinical trials in the future.

Highlights

Extraction of Sericin by High Temperature and High Pressure (Autoclave) Technique. This extraction method by high temperature and high pressure technique is simple and can be performed without using organic solvents in the process, which is suitable for industrial applications
The molecular weight of sericin in our extract was estimated by comparison with a molecular weight marker (Precision Plus ProteinTM Blue Unstained Protein Standard, Strep-tagged recombinant in the MW range of 10–250 KDa) Bio-Rad, CA, USA) using SDS-PAGE The result showed the molecular weight of sericin ranged from 37 to 250 kDa (Figure S1)
The pore size was calculated using Image J software, and the results showed that SN2 (0.20% alginate without PWCC)

Summary

Introduction

Skin is the first barrier for protection from the external environment. Dermal macrophages release inflammatory mediators including tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 and IL-1β that are involved the inflammatory immune response and wound healing [1]. Plants contain active agents such as flavonoids, phenolics, triterpenes, cinnamic acid, and anthocyanins that have anti-inflammatory properties [2]. It is interesting to develop natural plant extracts as topical formulations for anti-inflammatory products. Hydrogels have been widely used for biomedical applications such as controlled drug release, biocompatibility, and increasing drug stability, as well as providing a moist environment and helping to reduce inflammation during skin wound healing [3]. Hydrogels are hydrophilic polymer chains with a 3D-crosslinked structure, a high-water content, and Licensee MDPI, Basel, Switzerland

Methods

Results

Conclusion