Several infuenza pandemics have impacted our life, each with variable prevalence and severity. In a search for natural 
antivirals, further phytochemical investigation of Gardenia latifolia Aiton, Rubiaceae, was conducted. As a result, fve 
structurally diverse glycosides were isolated, ofering valuable chemotaxonomic data. Using the crystal violet technique, 
three isolates, canthoside C, (6R,7S,8S)-7α-[(β-d-glucopyranosyl) oxy] lyoniresinol, and ecdysanrosin A, were evaluated 
for their anti-infuenza A (H1N1) activities. Based on previously reported anti-infammatory activity of the guaiane class, 
we investigated the inhibitory efect of (1R,7R,8S,10R)-7,8,11-trihydroxy-guai-4-ene-3-one 8-O-β-d-glucopyranoside, a 
rare guaiane sesquiterpene glucoside, on inducible nitric oxide (NO) production by Griess assay. Regarding antiviral assay, 
canthoside C was the most active. It considerably inhibited H1N1 infectivity at an IC50 value of 10.93 µg/ml, showing a 
selectivity index (SI) of 12.88, compared with acyclovir as a standard. Besides, ecdysanrosin A displayed a moderate selective 
antiviral activity with an IC50 value of 28.03 µg/ml. Considering their low cytotoxicity on the host cells, canthoside C and 
ecdysanrosin A have additional merit as potential antiviral agents. Despite the claimed anti-infammatory activity of guaianes, 
(1R,7R,8S,10R)-7,8,11-trihydroxy-guai-4-ene-3-one 8-O-β-d-glucopyranoside showed a limited anti-infammatory activity