Pharmacologically active phenylpropanoids from Senra incana.

Coniferaldehyde, scopoletin, sinapaldehyde, and syringaldehyde were isolated from an aqueous extract of Senra incana. All four compounds inhibited prostaglandin synthetase in a dose-dependent way. Compared to aspirin, the potency of coniferaldehyde and scopoletin was about five times higher, whereas syringaldehyde and sinapaldehyde had about half the potency of this reference compound. On topical application, sinapaldehyde and scopoletin dose-dependently inhibited ethyl phenylpropiolate-induced edema of the rat ear. The active dose range was 1-10 micrograms/ear. Higher doses had a lower effect. Syringaldehyde was active in the range 20-100 micrograms/ear, whereas the effect of coniferaldehyde was inconclusive. Coniferaldehyde and sinapaldehyde inhibited electrically induced contractions of the guinea pig ileum in a dose-dependent way. Syringaldehyde showed a weak inhibition at a concentration of 550 microM.