Table 2.

Cytotoxic data of norcembranoidal diterpenes 1 and 2.

Compounds	Cell lines IC50 (μg/mL)
	K562	MOLT-4	HTC-116	DLD-1	T-47D	MDA-MB-231
1	0.67	0.59	4.09	0.92	3.09	2.95
2	NA	NA	NA	NA	NA	NA
Doxorubicin a	0.15	0.01	1.11	0.22	0.40	1.30

^a Doxorubicin was used as positive control. NA = not active at 20 μg/mL for 72 h.