Ethnopharmacological relevance: Iris is the largest genus in the family Iridaceae. Iris plants are distributed in
tropical regions of the world. They are used as ornamentals and traditionally used to treat a variety of ailments.
Aim: This study aimed to evaluate the anti-inflammatory effect of flavonoids isolated from Iris spuria L.
Materials and methods: The isolated flavonoids (1-4) were identified on the basis of different spectroscopic
methods (1D- and 2D-NMR) and co-TLC with authentic samples. The anti-inflammatory effect was tested on
lipopolysaccharide (LPS)-induced nitric oxide (NO) production from rat-isolated peritoneal macrophages.
Modeling and docking simulations of the compounds were performed using Molecular Operating Environment
software and the crystal structure of the murine inducible nitric oxide synthase (iNOS).
Results: Four flavonoids (1-4) had been isolated from the rhizomes of Iris spuria L. (Hocka Hoona) for the first
time. They were characterized as 5,7,2’-trihydroxy-6-methoxyflavanone (1), tectorigenin 7-O-β-D-glucopyranoside
(2), tectorigenin 4’-O-β-D-glucopyranoside (3), and tectorigenin 4’-O-[β-D-glucopyranosyl(1 → 6)-β-Dglucopyranoside]
(4). The selective inducible NO synthase inhibitor; aminoguanidine was used as a positive
control. The production of nitric oxide (NO) was inhibited in a dose-dependent manner of the isolated compounds
along with isoflavonoids (5-9) previously isolated from Iris spuria L. (Calizona). A concentration of 60 μg/
ml of all tested compounds showed a significant inhibitory effect compared to media with LPS. Molecular
modeling experiments supported the obtained biological data.
Conclusion: Our results reveal that flavonoids isolated from I. spuria L. (Hocka Hoona) and I. spuria L. (Calizona)
appear to have a potential anti-inflammatory effect via inhibition of iNOS