Further Thymol Derivatives from Ageratina cylindrica

From the leaves of Ageratina cylindrica, in addition to the described (2S)‐2‐{4‐formyl‐5‐hydroxy‐2‐(2‐methylpropanoyl)oxy]phenyl}oxiran‐2‐yl]methyl benzoate (cylindrinol A, 8 ), seven new thymol derivatives were isolated and named cylindrinols B – H ( 1 – 7 ). The structures of these compounds were established as (2‐{4‐(hydroxymethyl)‐2‐(2‐methylpropanoyl)oxy]phenyl}oxiran‐2‐yl)methyl benzoate ( 1 ), (2‐{4‐formyl‐2‐(2‐methylpropanoyl)oxy]phenyl}oxiran‐2‐yl)methyl benzoate ( 2 ), (2‐{4‐(acetyloxy)methyl]‐2‐(2‐methylpropanoyl)oxy]phenyl}oxiran‐2‐yl)methyl benzoate ( 3 ), 2‐(2‐(2‐methylpropanoyl)oxy]‐4‐{(2‐methylpropanoyl)oxy]methyl}phenyl)oxiran‐2‐yl]methyl benzoate ( 4 ), 2‐(5‐hydroxy‐2‐(2‐methylpropanoyl)oxy]‐4‐{(2‐methylpropanoyl)oxy]methyl}phenyl)oxiran‐2‐yl]methyl benzoate ( 5 ), 2‐{4‐(hydroxymethyl)‐2‐(2‐methylpropanoyl)oxy]phenyl}prop‐2‐en‐1‐yl benzoate ( 6 ), and 2‐hydroxy‐2‐2‐hydroxy‐4‐(hydroxymethyl)‐phenyl]‐3‐(2‐methylpropanoyl)oxy]propyl benzoate ( 7 ), by spectroscopic means. Compounds 1 showed moderate antiprotozoal activity on both protozoa. Compounds 4 and 5 showed selectivity on Giardia lamblia trophozoites. All isolated compounds were less active than two antiprotozoal drugs, metronidazole and emetine, used as positive controls. Compound 5 exhibited a high inhibitory effect on hyperpropulsive movement of the small intestine in rats; its effect was best than loperamide, antidiarrheal drug used as a positive control.