Table 1.

The observed IR bands (cm^-1) of the extract compounds of Betulaceae species, and the pure references species betulin (B), lupeol (L) and betulinic acid (BA) together with their assignments based on our previous DFT calculations[3]of betulin

IR	IR	IR	IR	IR	IR	Assignments
Betula utilisextract from ref.[11]	Isolated triterpenes fromBetula Pendula Roth,ref.[10]	Extract BC1 fromBetula Pendula Roth	Betulin (B)	Betulinic acid (BA)	Lupeol (L)
3433 (B)	-	-	3471vs	3431	-	ν (OH)
-	-	-	3465 sh	-	-	ν (OH))
-	3384 (BA)	3362 s	3362 s	-	3309 s	ν (OH)
	3348 (B)
	3308 (L)
-	-	-	3212 m	3225	-	ν (OH)
-	-	2940 vs	2968 vs	2943 vs	2982 s	νas(CH3) + νas(CH2) + νas(CH)
					2957 s
					2942 vs
-	-	-	2929 vs	-	2928 sh	νas(CH2) + ν(CH2) + ν(CH)
-	2870 (BA)	2867 s	2866 vs	2878 vs	2874 vs	+ ν(CH2+ ν(CH2)
	2868 (B)				2845 sh
	2872(L)
1725 (B) 1672 (BA)	1686, BA	1709-1684, broad	1735 w, 1708 sh	1716 sh, 1681 vs	-	ν(C = O)
1648 (B)	1638)(B)	1642	1642 m	1642 m	1642 m	δ(CH2) + ν((C = C) + δ(C-C-H)
	1630 (L)
1600 (B) 1560 (B)	-	1601	-	-	-	-
-	1468 (L) 1432 (BA, B)	1484 m 1452 s	1485 m 1450 s	1451	1453 m	δ(CH3) + δ(CH2)
-	1362 (O-H, BA); 1380 (L) 1388 (B)	1373 m	1373 m	1377 m	1374 m	δ(CH3) + δ(CH2)
1230 (B) 1240(BA)	-	-	-	1232 m	-	δ(OH) + τ(CH2) + δ(CH)
-	1156 (BA)	1190 m	1190 m	1190 m	1190 m	ν(C-C) + δ(OH) + τ(CH2) + δ(CH)
1028 (BA)	920 (L)	1028 s	1032 ms	1043 m	1046 m	ν(C-O) from CH2-OH, + δ(CH) + ρ(CH3, CH2)
-	-	1006 sh	1006 vs	-	-	ν(C-O) + δ(CH) + ρ(CH3-CH2)
		984 m
881 (B)	920 (L)	881 ms	875 ms	885 ms	895 s	ω (H-C-H) umbrella alkene

Abbreviations: v-very, s- strong, m-medium, sh-shoulder, ν -stretching, δ -bending, τ -torsion, ρ-rocking; B-betulin, BA-betulinic acid, L-lupeol.