Impact of solvent selection on the extraction of total phenolic content and total flavonoid content from kaffir lime leaves: Ultrasonic assisted extraction (UAE) and microwave assisted extraction (MAE)

2021 ◽  
Author(s):  
A. Anuar ◽  
M. A. Awang ◽  
H. F. Tan
Author(s):  
Ion Trandafir ◽  
Sina Cosmulescu ◽  
Violeta Nour

Abstract Total phenolic content, total flavonoid content, antioxidant activity and individual phenolic compounds were assessed in full fat and defatted walnut kernel. For quantification of phenolic fraction of walnut kernels, two different solvents (methanol and ethanol) and two methods of extraction (ultrasonic-assisted extraction and Soxhlet extraction) were tested. Total phenolics, flavonoid content and antioxidant capacity of alcoholic extracts varied depending on the solvent used and extraction methods. Seventeen phenolic compounds were detected and the study provides evidence on high phenolic contents and high antioxidant potential of full fat walnut kernel and defatted walnut kernel. The Soxhlet extraction is the best in terms of the amounts of total phenolic content (2,089.2 mg gallic acid equivalent/100 g dry matter), while the ultrasonic assisted extraction is a fast method but resulted in significantly lower phenolic content (667.3–1,426.8 mg gallic acid equivalent /100 g dry matter). The concentrations of phenolics (especially (+)-catechin hydrate, juglone, vanillic acid, caffeic acid, ferulic acid, sinapic acid, salicylic acid and ellagic acid) are many fold lower in ultrasonic-assisted extraction as compare to the Soxhlet method using the same extraction solvent. The results of this study provide evidence on high phenolic contents and high antioxidant potential of full fat and defatted walnut kernel.


Food Research ◽  
2020 ◽  
Vol 4 (5) ◽  
pp. 1710-1718 ◽  
Author(s):  
N.S.M. Shafie ◽  
M.S. Latif ◽  
M.I. Ghazali ◽  
S. Abbas ◽  
F. Kormin

Clinacanthus nutans is a great medicinal herb with high polyphenols content and had been used in its infusion form to treat illness. In this paper, microwave-assisted extraction of C. nutans tea infusion was investigated by using central composite design combined with response surface methodology. The influence factors of microwave power (80 - 800 W); brewing time duration (0 – 240 s) and extraction time duration (60 s – 300 s) on total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity (DPPH) and acetylcholinesterase inhibition activity (AChE) were investigated. The optimum extraction conditions were determined as follows: microwave power X1, 560 W; brewing duration, X2, 60 s and extraction time, X3, 240 s. Under this optimal extraction conditions, the responses were as followed: Total phenolic content (251.58±10.98 mg GAE/L); Total flavonoid content (102.21±5.16 mg RE/L); DPPH (62.22±0.03%) and acetylcholinesterase inhibition activity (AChE) of 24.77±0.12%. Results demonstrated that MAE could be used to extract bioactive constituents having antioxidant and anti-acetylcholinesterase properties that may benefit in Alzheimer’s disease.


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