Natural phenanthrenes and their biological activity.

Chemical constituents from Dendrobium densiflorum.

A commercial aqueous smoke preparation was exhaustively extracted, using dichloromethane as solvent, until the carrier had totally lost its smoky odor. Qualitative and quantitative characterizations of the extract were performed by means of gas chromatography/mass spectrometry and gas chromatography with flame ionization detector, respectively. Carbonyl derivatives including aldehydes and ketones as well as acids and esters are almost absent; however, the high proportion of phenol, guaiacol, and syringol derivatives is noticeable. The presence of di-tert-butylhydroxytoluene, several hopanes, and a number of lignin dimers must be pointed out; these latter components had apparently not been detected before either in smoke flavorings or in wood smoke. The mass spectral data of the compounds considered as lignin dimers and of the unidentified components are given. The presence of lignin dimers is very interesting from the point of view of health and food technology for their therapeutic, organoleptic, and antioxidant properties.

Walter C. Taylor

Papers

Phenanthrenes of Eulophia nuda

Bioactive butenolides from Melodorum fruticosum