Chemical investigation of the leaves from
Ageratina glabrata yielded four new thymol derivatives, namely: 10-benzoyloxy-8,9-dehydro-6-hydroxythymol isobutyrate (
4), 10-benzoyloxy-8,9-dehydrothymol (
5), 10-benzoyloxythymol (
6) and 10-benzoyloxy-6,8-dihydroxy-9-isobutyryl-oxythymol (
7). In addition, (8
S)-10-benzoyloxy-8,9-epoxy-6-hydroxythymol isobutyrate (
1), together with
[...] Read more.
Chemical investigation of the leaves from
Ageratina glabrata yielded four new thymol derivatives, namely: 10-benzoyloxy-8,9-dehydro-6-hydroxythymol isobutyrate (
4), 10-benzoyloxy-8,9-dehydrothymol (
5), 10-benzoyloxythymol (
6) and 10-benzoyloxy-6,8-dihydroxy-9-isobutyryl-oxythymol (
7). In addition, (8
S)-10-benzoyloxy-8,9-epoxy-6-hydroxythymol isobutyrate (
1), together with other two already known thymol derivatives identified as 10-benzoyloxy-8,9-epoxy-6-methoxythymol isobutyrate (
2) and 10-benzoyloxy-8,9-epoxythymol isobutyrate (
3) were also obtained. In this paper, we report the structures and complete assignments of the
1H and
13C-NMR data of compounds
1–
7, and the absolute configuration for compound
1, unambiguously established by single crystal X-ray diffraction, and evaluation of the Flack parameter. The in vitro antiprotozoal assay showed that compound
1 and its derivative
1a were the most potent antiamoebic and antigiardial compounds. Both compounds showed selectivity and good antiamoebic activity comparable to emetine and metronidazole, respectively, two antiprotozoal drugs used as positive controls. In relation to anti-propulsive effect, compound
1 and
1a showed inhibitory activity, with activities comparable to quercetin and compound
9, two natural antipropulsive compounds used as positive controls. These data suggest that compound
1 may play an important role in antidiarrheal properties of
Ageratina glabrata.
Full article
