Development and Validation of a HPLC-UV Method for the Evaluation of Ellagic Acid in Liquid Extracts of Eugenia uniflora L. (Myrtaceae) Leaves and Its Ultrasound-Assisted Extraction Optimization

Table 1

Levels of variables for the Box Behnken (3³) experimental design.

Symbols	Independent variables	Levels
		−1	0	+1
	Ethanol (%, w/w)	40	60	80
	Temperature (°C)	30	45	60
	Extraction time (minutes)	20	30	40

= ethanol; = temperature; = extraction time.