Optimisation of Ultrasound-Assisted Extraction Conditions for Phenolic Content and Antioxidant Capacity from Euphorbia tirucalli Using Response Surface Methodology.

Quan Vuong,Deep Bhuyan,Chloe Goldsmith,Christopher Scarlett,Michael Bowyer,Trung Dang,Van Nguyen,Elham Sadeqzadeh

doi:10.3390/antiox3030604

Quan Vuong, Deep Bhuyan + Show 6 more

Open Access

https://doi.org/10.3390/antiox3030604

Copy DOI

Abstract

Euphorbia tirucalli (E. tirucalli) is now widely distributed around the world and is well known as a source of traditional medicine in many countries. This study aimed to utilise response surface methodology (RSM) to optimise ultrasonic-assisted extraction (UAE) conditions for total phenolic compounds (TPC) and antioxidant capacity from E. tirucalli leaf. The results showed that ultrasonic temperature, time and power effected TPC and antioxidant capacity; however, the effects varied. Ultrasonic power had the strongest influence on TPC; whereas ultrasonic temperature had the greatest impact on antioxidant capacity. Ultrasonic time had the least impact on both TPC and antioxidant capacity. The optimum UAE conditions were determined to be 50 °C, 90 min. and 200 W. Under these conditions, the E. tirucalli leaf extract yielded 2.93 mg GAE/g FW of TPC and exhibited potent antioxidant capacity. These conditions can be utilised for further isolation and purification of phenolic compounds from E. tirucalli leaf.

Highlights

Euphorbia tirucalli (E. tirucalli) is native to Madagascar and Africa, but it is widespread around the world because of its tolerance to a wide range of climatic conditions [1,2]
It is necessary to test the reliability of the response surface methodology (RSM) mathematical model in predicting optimal variances and accurately representing the real interrelationships between the selected parameters
The current findings showed that ultrasonic temperature, time and power affected the antioxidant capacity of the E. tirucalli extract; temperature had the highest impact, followed by power, while time had the least impact on antioxidant capacity of the E. tirucalli extract

Summary

Introduction

Euphorbia tirucalli (E. tirucalli) is native to Madagascar and Africa, but it is widespread around the world because of its tolerance to a wide range of climatic conditions [1,2]. It has been linked to other benefits including hepatoprotective, antimicrobial, antioxidant, insecticidal, larvicidal, molluscicide and antiarthritic activities [6], which have resulted in significant scientific interest in the phytochemical profile of the plant [1]. Phenolic and terpenoid compounds have been identified in the phytochemical profile of E. tirucalli, and extracts have been shown to possess potent antioxidant properties [7,8]. Phenolic compounds are major bioactive compounds in medicinal plants and have been reported as powerful antioxidants and health promoters. The phenolic profile and antioxidant properties of E. tirucalli have been reported in a previous study, which found that acetone extracts yielded a higher concentration of phenolics than more polar solvent systems (80% aqueous methanol) [8]. Optimal extraction conditions were not investigated and further study is required to fully characterise the phenolic profile

Objectives

Results

Conclusion