Chemistry and antinociceptive activity of the traditional preparation and compounds from Ageratina grandifolia (Regel) King & H. Rob. (Asteraceae)

The traditional preparation and major compounds [3,5-diprenyl-4-hydroxyacetophenone ( 1 ), O -methylencecalinol ( 2 ), encecalin ( 3 ), and encecalinol ( 4 )] of Ageratina grandifolia [ 1 ], tested at doses of 10, 31.6, and 100 mg/kg, administered intragastrically, demonstrated a significant antinociceptive effect in both phases of the formalin test in mice. Encecalinol ( 4 ) was the most active compound, exhibiting a dose-dependent antinociceptive action in both phases ([ Fig. 1 ]); its effect was substantially reduced when the mice were pretreated with naloxone. Additionally, four new chemical entities were identified, including 2-hydroxy-α-truxillic acid ( 5 ), (3 R ,4 S )-2,2-dimethyl-3-hydroxy-4-(1-angeloyloxy)-6-acetyl-7-methoxychromane ( 6 ), N -tricosanoyltyramine ( 7 ), and grandifolamide ( 8 ). The volatile constituents of A. grandifolia were characterized using gas chromatography-mass spectrometry analysis of the components obtained through head-space solid microextraction and hydrodistillation. The volatile compounds contained a high percentage of chromenes, caryophyllene, germacrene D, spathulenol, and caryophyllene oxide. A suitable liquid chromatographic method was developed and validated to simultaneously quantify three significant flavonoids in the ethyl acetate soluble fraction of the traditional preparation, specifically 6-hydroxykaempferol-7- O -β-D-glucopyranoside, quercetagetin-7- O -[6- O -caffeoyl-β-D-glucopyranoside, and 6-hydroxykaempferol-7- O -[6- O -caffeoyl-β-D-glucopyranoside]. Fig. 1 Antinociceptive effect of encecalinol ( 4 ) at 100 mg/kg ( p.o .) in combination with naloxone (NAL; 3.2 mg/kg, p.o .) using the formalin test in mice. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany