Table 2. IC₅₀ values for SAHA, Tubastatin, SAHA analogs 1b-1f, (R)-1f, and (S)-1f against HDAC1, 2, 3, 6 and 8, and EC₅₀ values with U937 cells.

Compound	IC50 values (nM)a					EC50 (μM)b,c
	HDAC1	HDAC2	HDAC3	HDAC6	HDAC8	U937 cells
SAHAd	33 ± 1	96 ± 10	20 ± 1	33 ± 3	540 ± 10	0.88 ± 0.13
Tubastatind	2,700 ± 200	3,900 ± 400	2,900 ± 500	31 ± 4	330 ± 10	83 ± 8
PCI-34051	–	–	–	–	–	210 ± 30
1b (ethyl)	4,400 ± 300	4,900 ± 400	6,000 ± 1200	160 ± 10	130 ± 3	–
1c (n- butyl)	15,000 ± 1000	18,000 ± 2000	23,000 ± 3000	88 ± 7	74 ± 2	34 ± 2
1d (n-hexyl)	35,000 ± 1000	38,000 ± 3000	30,000 ± 3000	140 ± 10	79 ± 3	16 ± 3
1e (phenyl)	11,000 ± 1000	12,000 ± 1000	23,000 ± 2000	110 ± 10	290 ± 20	–
1f (benzyl)	29,000 ± 1000	32,000 ± 2000	42,000 ± 4000	140 ± 10	57 ± 2	28 ± 7
(R)-1f	25,000 ± 2000	36,000 ± 3000	27,000 ± 2000	48 ± 8	27 ± 2	–
(S)-1f	40,000 ± 1000	51,000 ± 1000	37,000 ± 2000	95 ± 9	150 ± 10	–

^aMean IC50 value and standard error of at least three independent trials are shown (Figures S142-S148 and Tables S3-S9).

^bMean EC50 value and standard error of at least three independent trials are shown. Data in table is associated with Figures S150 and Table S11.

^c“–” represents not determined.

^dPreviously reported IC50 values using the same assay procedure [28, 42].