Optimization of Ultrasonic Assisted Extraction of Bioactive Polyphenols from Wood Waste of Cedrela toona Using Response Surface Methodology

Abstract

Background: Wood waste is a readily available resource with significant potential for applications in medicine, pharmaceuticals and nutraceuticals due to its abundance of bioactive compounds, particularly polyphenols. Objective: To optimize a sustainable extraction method using surface response methodology (SRM) to efficiently extract bioactive compounds, including polyphenols from wood waste of Cedrela toona Methods: The ultrasonic-assisted extraction of Cedrela toona was optimized using water as a solvent with a three-level Box-Behnken Design of SRM, varying parameters including temperature (30, 50, 70°C), time (15, 37.5, 60 min), and wood-to-solvent ratio (1:10, 2:15, 3:20 g/L) under 15 extraction parameter combinations. Total polyphenolic content (TPC) of the 15 different extracts was assessed using the Folin-Ciocalteu method to identify the polyphenol rich wood extracts (PRWE). The phytochemicals contained in the PRWE were qualitatively analyzed using standard methods including Wagner’s test for alkaloids, glycoside test, ferric chloride test for tannins, flavonoid test, saponin test, Salkowski test for steroids and phenol test. The total flavonoid content (TFC) of PRWE was quantitatively assessed utilizing the aluminum chloride method. The PRWE was investigated employing DPPH free radical scavenging and protein egg albumin denaturation assays with Trolox and diclofenac sodium serving as the positive controls, respectively. Zebrafish embryo assay was employed for the acute toxicity study of PRWE. Results: The highest TPC was determined to be 17.12±2.46 GAE/g for the optimized extraction conditions of 50°C, 37.5 minutes, and 2:15 g/L. Phytochemical screening confirmed the presence of alkaloids, glycosides, flavonoids, phenols, saponins, tannins, and steroids in PRWE. The TFC of PRWE was 16.58±0.72 mg QE/g of extract. The PRWE exhibited moderate in vitro anti oxidant (IC50; 10.98 ± 0.41 µg/mL) and anti-inflammatory (IC50; 248.95±2.9 µg/mL) properties in comparison to the reference standards, Trolox (IC50; 5.95±0.02 µg/mL) and diclofenac sodium (IC50; 179.95±1.33 µg/mL) used for anti-oxidant and anti-inflammatory assays, respectively. According to the acute toxicity study, median lethal concentration (LC50) corresponding to 50% mortality of PRWE was 16.8±0.9 µg/mL. The results demonstrated that 100% mortality rates at concentrations exceeding 20.00 ±0.63 µg/mL.

Conclusion: An efficient extraction method was successfully optimized using SRM to extract bioactive polyphenols from wood waste of Cedrela toona.