Flavonoids ofGoebelia pachycarpa
The following substances were isolated and were identified on the basis of chemical and spectral characteristics: kaempferol, quercetin, and genistein. A fourth compound C26H2sO14 (I), mp 125-128°C, [a]~ 2 --34.4 ± 2 ° (c 1.05 MeOH) was an isoflavone derivative according to its UV spectrum (%maxethanol, nm: 263, 328 sh; log g 4.56, 3.73) [i]. Its IR spectrum contained absorption bands at (cm -I) 3527-3295 (OH groups), 1660 (C=O of a a-pyrone), 1622, 1589 (aromatic ~ bonds), and 1098-1040 (C O vibrations of glycosides).
The Ultraviolet Spectra of Isoflavones, Flavanones and Dihydroflavonols
Isoflavones, flavanones and dihydroflavonols all give similar UV spectra as a result of their having little or no conjugation between the A- and B-rings. They are all readily distinguished from flavones and flavonols by their UV spectra, which typically exhibit an intense Band II absorption with only a shoulder or low intensity peak representing Band I.
METABOLIC PRODUCTS OF MICROORGANISMS. 163
Aspergillus deflectus CBS 109.55 when grown on an iron-free medium produces several antibiotics; one of these was isolated and identified as desferritriacetylfusigen. It inhibits the growth of bacteria, whereas yeasts and fungi are not or only weakly affected.