Optimization of Piper betle L. extraction under ultrasound and its effects on chitosan/polyvinyl alcohol film properties for wound dressing.

This study aimed to prepare Piper betle L. extract-load chitosan/polyvinyl alcohol (CS/PVA) film potential for wound dressing and investigate the effects of PLE and PLE-loading methods on physicochemical and biological properties of CS/PVA films. First, Piper betle L. extract (PLE) was optimized using ultrasonication and the response surface methodology employed the Box-Behnken design to maximize total phenolic content (TPC), total flavonoid content (TFC), and natural antioxidant activity. The optimal ultrasonic conditions resulting in an extract yield of 17.466 %, TPC of 261.904 mg GA/g, TFC of 148.726 mg Q/g, and IC of 53.100 mg/L were achieved with a sonication time of 3.958 min, power of 30.548 W, and duty cycle of 84.576 % using water as the green solvent. The systematic analysis explored the effects of extraction duration, power, and pulse mode providing valuable insights into novel extraction techniques for potential pharmaceutical applications. Subsequently, PLE was incorporated into a CS/PVA biocomposite film using two loading methods: direct mixing and immersion. The study revealed that the immersion method offers several advantages related to the physicochemical and biological properties of the PLE-treated CS/PVA film. These advantages include improved PLE bioavailability (with PLE releasing 81.42 ± 2.44 % over 24 h, 8.6 times higher than the direct mixing method), removal of excess acetic acid from the manufacturing process of CS/PVA film, which causes cell cytotoxicity (L929 cell viability of 70.47 ± 2.18 %), enhanced tensile strength of 1.19 times greater than the original CS/PVA film, and efficient exudate absorption (allowing appropriate water vapor transmission at a rate of 2477.00 ± 35.39 g/m·day). The results show the prepared PLE-treated CS/PVA film is a potential candidate for wound dressing, and the immersion method represents an advanced drug-loading method, especially for medicinal herbs on CS/PVA thin film surfaces.