TABLE 1.

Summary of the IC₅₀ values of compounds 4a-c, 5a-c and oridonin for the inhibition of NO production.

Compound	IC50 (μM)	7,20-Epoxy ent-kaurane diterpenoid scaffold	6,20-Epoxy ent-kaurane diterpenoid scaffold
Oridonin	4.85 ± 0.15
4a	0.37 ± 0.01	√
5a	1.03 ± 0.15		√
4b	0.30 ± 0.02	√
5b	4.21 ± 3.99		√
4c	0.28 ± 0.01	√
5c	0.58 ± 0.16		√