Table 3.

Acetylcholinesterase inhibitory activity of Z. concolor alkaloids.

Alkaloid	EC50 (M)
Chlidanthine (1)	2.41 ± 0.50 × 10−5
Galanthamine (2)	5.16 ± 1.08 × 10−6
Galanthamine N-oxide (3)	2.62 ± 0.55 × 10−5
Galwesine (5) > 10−3

EC₅₀ values are means ± SD of three determinations (10⁻⁸ to10⁻³ M).