Myrtinols A-F: New Anti-Inflammatory Peltogynoid Flavonoid Derivatives from the Leaves of Australian Indigenous Plant Backhousia myrtifolia

Our in-house ethnopharmacological knowledge directed our anti-inflammatory investigation into the leaves of Backhousia mytifolia. Bioassay guided isolation of the Australian indigenous plant Backhousia myrtifolia led to the isolation of six new rare peltogynoid derivatives named myrtinols A-F (1-6) along with three known compounds 4-O-methylcedrusin (7), 7-O-methylcedrusin (8) and 8-demethylsideroxylin (9). The chemical structures of all the compounds were elucidated by detailed spectroscopic data analysis, and absolute configuration was established using X-ray crystallography analysis. All compounds were evaluated for their anti-inflammatory activity by assessing the inhibition of nitric oxide (NO) production and tumor necrosis factor- alpha (TNF-alpha) in lipopolysaccharide (LPS) and interferon (IFN)-gamma activated RAW 264.7 macrophages. A structure activity relationship was also established between compounds (1-6), noting promising anti-inflammatory potential by compounds 5 and 9 with an IC50 value of 8.51 +/- 0.47 and 8.30 +/- 0.96 mu g/mL for NO inhibition and 17.21 +/- 0.22 and 46.79 +/- 5.87 mu g/mL for TNF-alpha inhibition, respectively.

Automated summary

The anti-inflammatory investigation of the leaves of Backhousia myrifolia, an Australian indigenous plant, led to the discovery of six new peltogynoid derivatives named myrtinols A-F (1-6) and three known compounds 4-O-methylcedrusin (7), 7-O-methylcedrusin (8), and 8-demethylsideroxylin (9). The structures of all compounds were analyzed using spectroscopic data and X-ray crystallography. The compounds were evaluated for their anti-inflammatory activity, with compounds 5 and 9 showing promising potential.