Antiplasmodial Activity of Constituents Isolated from Croton lobatus.

Figures & data

Figure 1. Chemical structures of isolated compounds from Croton lobatus..

Table 1. ¹H and ¹³C NMR spectral data assignments for lobaceride (1) in CDCl₃ (¹³C at 75.4778 MHz and ¹H at 300 MHz). Chemical shifts are given in ppm, coupling constant J. values (in parentheses) are in Hertz.

	1
Position^a.	C	H
1,1′	173.3
2,2′	34.0	2.30, t.(7.8)
3,3′	22.7	1.60, m.
4,4′	29.2	1.24, br., s.
5,5′	27.2	2.05, m.
6,6′	130.0	5.34, m.(5.4, 7.8)
7,7′	128.1	5.34, m.(5.4, 7.8)
8,8′	25.6	2.78, dd.(5.4,6.0)
9,9′	127.6	5.34, m.(5.4, 7.8)
10,10′	130.2	5.34, m.(5.4, 7.8)
11,11′	27.2	2.05, m.
12,12′	14.1	0.87, t.(3.5)
13α	62.1	4.14, dd.(5.7,11.9)
13β		4.29, dd.(4.2,11.9)
14	68.9	5.26, tt.(5.7,4.2)
15α	62.1	4.14, dd.(5.7,11.9)
15β		4.29, dd.(4.2,11.9)
16	172.8
17	34.3	2.31, t.(7.8)
18	24.9	1.60, m.
19	29.3	1.24, br.
20	29.3	1.24, br.
21	22.7	1.24, br.
22	31.9	1.24, br.
23	14.1	0.97, t.(3.5)

^a.Assignments confirmed by DEPT, COSY, HMQC, and HMBC experiments.

Table 2. Antiplasmodial activity, cytotoxicity, and selectivity indices of isolated constitutents.

Compounds	P.falciparum K1. IC50 (µg/mL)	L6 IC50 (µg/mL)	SI
1	> 5	ND	ND
2	3.17	58.4	18.4
3	3.91	> 90	>20
4^a.	1.07 ± 0.3	27	25.1
5	> 5	ND	ND
6^a.	1.45 ± 0.0	6.59	4.5
7	4.86	47.9	9.9
Chloroquine	0.043	ND	ND
Artemisinin	0.0015	ND	ND

Plasmodium falciparum., K1 multiresistant strain; L6, murine myoblast cells; SI, cytotoxicity/antiplasmodial activity (selectivity index); ND, not determined.

^a.For compounds 4 and 6, IC₅₀ values are means ± SD (n = 2), p < 0.05.