Strychnos pseudoquina and Its Purified Compounds Present an Effective In Vitro Antileishmanial Activity

Table 1

Structural and chemical characterizations of the two flavonoids purified from S. pseudoquina. ¹H and ¹³C chemical shifts (ppm) obtained for quercetin 3-O-methyl ether and strychnobiflavone.

Positions	Quercetin 3-O-methyl ether (δ H)^a	Quercetin 3-O-methyl ether (δ H)^c	Quercetin 3-O-methyl ether (δ C)^a	Quercetin 3-O-methyl ether (δ C)^c	Strychnobiflavone (δ H)^b	Strychnobiflavone (δ H)^d	Strychnobiflavone (δ C)^b	Strychnobiflavone (δ C)^d
2	—	—	158.5^e	157.3	—	—	155.5	157.4
3	—	—	139.7	138.4	—	—	137.4	138.7
4	—	—	180.1	178.9	—	—	178.0	179.1
5	—	—	166.0	161.9	—	—	154.1	162.0
6	6.18; d; (𝐽=2.0 Hz)	6.21	99.9	98.6	6.16; s	6.26; s	97.9	98.8
7	—	—	163.2	164.8	—	—	159.9	164.2
8	6.37; d; (𝐽=2.0 Hz)	6.41	94.8	93.5	—	—	102.8	103.6
9	—	—	158.1^e	156.8	—	—	161.2	155.5
10	—	—	106.0	104.7	—	—	104.0	105.5
1′	—	—	123.6	121.8	—	—	121.1	123.0
2′	7,61; d; (𝐽=2.0 Hz)	7.64	116.5^f	115.3	7.44; d; (𝐽=2.0 Hz)	7.60; d; (𝐽=2 Hz)	115.9	124.0
3′	—	—	146.6	145.3	—	—	145.1	148.7
4′	—	—	150.1	148.8	—	—	148.6	145.3
5′	6,89; d; (𝐽=8.4 Hz)	6.92	116.6^f	115.2	6.71; d; (𝐽=8.4 Hz)	6.82; d; (𝐽=8 Hz)	115.4	115.7
6′	7,51; dd; (𝐽=8.4 Hz; 2.0 Hz)	7.55	122.5	121.2	7.05; dd; (𝐽=8.4 Hz; 2.0 Hz)	7.29; dd; (𝐽=8 Hz; 2 Hz)	120.2	121.7
2′′	—	—	—	—	—	—	159.1	157.4
3′′	—	—	—	—	—	—	138.2	138.7
4′′	—	—	—	—	—	—	177.8	179.0
5′′	—	—	—	—	—	—	156.3	161.9
6′′	—	—	—	—	6.07; d; (𝐽=1.6 Hz)	6.10; (𝐽=2 Hz)	98.4	98.9
7′′	—	—	—	—	—	—	163.9	162.5
8′′	—	—	—	—	5.66; d; (𝐽=1.6 Hz)	5.84; d; (𝐽=2 Hz)	92.8	93.6
9′′	—	—	—	—	—	—	161.2	156.4
10′′	—	—	—	—	—	—	104.2	105.5
1′′′	—	—	—	—	—	—	122.3	122.9
2′′′	—	—	—	—	—	—	119.7	116.2
3′′′	—	—	—	—	—	—	144.2	147.9
4′′′	—	—	—	—	—	—	147.5	148.8
5′′′	—	—	—	—	6.97; d; (𝐽=8.4 Hz)	7-7.1; m	114.1	114.9
6′′′	—	—	—	—	7.05; d; (𝐽=8.4 Hz)	7-7.1; m	121.4	119.8
3-O-Me	3.77; s	3.80	60.6	59.35	3.79; s	3.82; s	59.8	60.3
3′′-O-Me	—	—	—	—	3.43; s	3.63; s	59.6	59.9
5-OH	12.47; s	—	—	—	12.68; s	12.8; s	—	—
5′′-OH	—	—	—	—	12.56; s	12.6; s	—	—

aCD₃OD; ^bDMSO-d ₆; ^cDMSO-d ₆ (Guinot et al. 2009 [22]); ^dacetone-d ₆ (Nicoletti et al. 1984 [20]); ^e,finterchangeable.