Table 1. Inhibition Constants (K_i, μM) for the Nojirimycin N,C-Biantennary Derivatives 19–26 and 27–32, in Comparison with Data for the Nojirimycin α-C-Glycosides 13 and 16^a.

compd	α-Glcase baker’s yeast	α-Glcase rice	amyloglcase A. niger	β-Glcase T. maritima	β-Glcase almonds	β-Glcase bovine	α-Galase coffee
13	92 ± 8	11 ± 1	67 ± 5	657 ± 65	nib	ni	ni
19	ni	ni	ni	ni	ni	117 ± 12	ni
20	ni	25 ± 3	ni	ni	ni	358 ± 35	130 ± 12
21	ni	8.2 ± 0.6	ni	ni	ni	136 ± 11	ni
22	ni	11 ± 0.7	ni	ni	ni	ni	ni
23	ni	583 ± 0.2	154 ± 12	ni	ni	ni	ni
24	ni	72 ± 6	455 ± 40	ni	ni	ni	ni
25	ni	340 ± 30	842 ± 75	ni	ni	ni	ni
26	ni	104 ± 9	ni	ni	ni	ni	ni
16	10.7 ± 0.9	0.38 ± 0.04	12.3 ± 2	29 ± 3	28 ± 2	32 ± 3	87 ± 9
27	119 ± 10	3.3 ± 0.5	92 ± 8	293 ± 25	ni	169 ± 15	508 ± 35
28	ni	4.3 ± 0.6	455 ± 40	ni	ni	ni	ni
29	439 ± 35	ni	ni	16 ± 1	75 ± 5	177 ± 14	ni
30	ni	ni	ni	280 ± 25	ni	ni	ni
31	ni	ni	842 ± 80	ni	ni	134 ± 10	ni
32	ni	ni	305 ± 28	ni	ni	ni	ni

^aThe inhibition was competitive in all cases. No inhibitory activity was detected for any of the compounds at 2 mM against jack bean α-mannosidase, Helix pomatia β-mannosidase, or E. coli β-galactosidase at 2 mM concentration.

^bNo inhibition observed at 2 mM concentration.