ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Optimisation studies on polyphenol production from Azadirachta indica leaves—influence of operating conditions

Santosh A. Kadapure, Umesh B. Deshannavar, Amith G. Gadagi, Prasad G. Hegde, and Natarajan Rajamohan

Department of Chemical Engineering, Tatyasaheb Kore Institute of Engineering and Technology, Warana University, Warananagar, India

E-mail: deshannavar@gmail.com

Received: 24 April 2025  Accepted: 30 July 2025

Abstract:

Integrating with microwave-assisted extraction, deep eutectic solvents present a sustainable and efficient alternative to conventional organic solvents for extracting polyphenols from Azadirachta indica leaves. Choline chloride-ethylene glycol at various mole ratios and water contents was evaluated for its effectiveness in extracting polyphenol compounds. The results demonstrated that the interaction between leaves, water, and deep eutectic solvents significantly affected the total phenolic content. A precise optimisation of deep eutectic solvent extraction, employing a 1:3.5 or 1:6 molar ratio, a 12.5 feed-to-solvent ratio, and 17.5% water, yielded maximum phenolic compound extraction, characterised by Folin–Ciocalteu quantification and confirmed via GC–MS identification of key phenolic classes, corroborated by FTIR spectral analysis of relevant functional groups. Deep eutectic solvent-assisted microwave-assisted extraction demonstrates exceptional promise as a sustainable methodology for optimising polyphenol recovery from Azadirachta indica foliage, as evidenced by our comprehensive investigation. Microwave-assisted extraction supports sustainability by enhancing energy efficiency, promoting circular economies, and upcycling waste into polyphenols using water-based solvents. A radial-basis artificial neural network was employed to develop a prediction model for total phenolic content, and it successfully predicted the total phenolic content values with an average error of 4.81%.

Keywords: Deep eutectic solvent; Polyphenols; Microwave; RSM; Radial-basis ANN

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04284-1

Chemical Papers 79 (11) 7725–7743 (2025)