Table 2.

Extraction of active principles from the birch bark

Mass of birch bark (Source)	Extraction solvent	Aspect of extract	Resulting samples
15 g (A)	2-Propanol (400 mL)	Cream-colored solution + white crystals deposited at the bottom of the flask	The white crystals: sample 1 pp
			Evaporation of solution and filtration: sample 1
15 g (A)	Ethanol (96% v/v) (400 mL)	Cream-colored solution	Evaporation of solution and filtration: sample 2
15 g (B)	2-Propanol (400 mL)	Cream-colored solution + white crystals	The white crystals: sample 3 pp
			Evaporation of solution and filtration: sample 3
15 g (B)	Ethanol (96% v/v) (400 mL)	Cream-colored solution	Evaporation of solution and filtration: sample 4

*Source A: birch bark collected in April 2010 from Ponoarele, Mehedinţi, Romania.

*Source B: birch bark collected in April 2010 from Aninei Mountains, Romania.