Fulvinervin C,a flavone from Tephrosia fulvinervis

From the seeds of Tephrosia fulvinervis a new flavone, fulvinervin C has been isolated along with the known flavanone fulvinervin A. Its structure is elucidated from chemical properties and spectral data.     

A chalcone and an isoflavone from Millettia pachycarpa seeds

Chemical examination of the seeds of Millettia pachycarpa has yielded a new prenylated isoflavone and a new prenylated chalcone in addition to the previously reported isoflavones 5-hydroxy-4′-methoxy-6″,6″-dimethylpyrano (2″,3″:7,8)isoflavone, 5,7,4′-trihydroxy-6,8-diprenylisoflavone, 5,7,3′,4′-tetrahydroxy-6,8-diprenyl-isoflavone and pomiferin.     

Mixtecacin,a prenylated flavanone and oaxacacin its chalcone from the roots of Tephrosia woodii

From the roots of Tephrosia woodii, a new Mexican Tephrosia species, a new prenylated flavanone, oaxacacin, and its chalcone, mixtecacin, have been isolated and their structures elucidated from their chemical properties and spectral data.     

Flavonoids from Millettia pulchra

Chemical examination of Millettia pulchra yielded (?)-maackiain, (?)-pterocarpin, (?)-sophoranone and the new compounds (6S, 6aS, 11aR)-6α-methoxypterocarpin, (6S, 6aS,11aR)-6α-methoxyhomopterocarpin, (2S)5,7,4′-trihydroxy-8,3′,5′-triprenylflavanone, (2R,3R)7,4′-dihydroxy-8,3′,5′-triprenyldihydroflavanol, 5,7,2′,4′-tetrahydroxy-6,3′-diprenylisoflavone and 5,7,4′-trihydroxy-2′-methoxy-6,3′-diprenylisoflavone.     

New prenylated isoflavones from Millettia pachycarpa

Isolation of four new isoflavones from a new collection of Millettia pachycarpa is reported. Proof of the structure of lupinifolol, previously isolated from M. pachycarpa, by synthesis of dehydrolupinifolol is described.     

Neue prenylflavanone aus Helichrysum hypocephalum

From the aerial parts of H. hypocephalum several new prenylated flavones were isolated, their structures being elucidated by spectroscopic methods and by some chemical transformations. In addition, a new lactone derived from oleic acid is present.     

Minor xanthones from Rheedia gardneriana

8-Deoxygartanin and two new xanthones, 1,5-dihydroxy-6′,6′-dimethyl-2H-pyrano(2′,3′:3,2)-6″,6″-dimethyl-2H-pyrano(2″,3″:6,7)xanthone and 1,5,6-trihydroxy-6′,6′-dimethyl-2H-pyrano(2′,3′:3,2)-7-(3-methylprop-2-enyl)xanthone, have been isolated from the roots of Rheedia gardneriana. The latter of the two new xanthones has been assigned the trivial name 7-prenyljacareubin while the former has the structure erroneously assigned to pyranojacareubin reported from Garcinia densivenia. The correct identity of the G. densivenia xanthone has been shown to be rheediaxanthone-A.     

Prenylated p-coumarates from Werneria stuebelii

The aerial parts of Werneria stuebelii afforded in addition to β-cedrene and bicyclogermacrene eight derivatives of methyl p-coumarate, all being formed by prenylation. The structures were elucidated by their molecular formulae and their ¹H NMR spectra. The chemotaxonomy of the Andean genus Werneria is discussed briefly.     

Rhynchospermin. A prenylated flavanol from Rhynchosia cyanosperma

A new flavanol has isolated from the leaves of Rhynchosia cyanosperma and identified as 8-C-prenylquercetin 7,4′-dimethyl ether (rhynchospermin).     

Erythrisenegalone,a prenylated-flavanone from Erythrina senegalensis

The isolation of a new prenylated flavanone, erythrisenegalone, from the stem-bark of Erythrina senegalensis is described. Its structure was established by spectroscopic methods and a few chemical transformations.     

Two isoflavones from Piscidia erythrina

Two new prenylated isoflavones were isolated from the root bark of Piscidia erythrina. The first compound was identified as 2′-deoxypiscerythrone. The second compound, the most abundant component of the extract, was identified as 3′-6′-di-Δ²-isopentenyl-5,7,2′,4′-tetrahydroxy-5′-methoxyisoflavone.     

Three prenylated flavanoids from Helichrysum athrixiifolium

Helichrysum athrixiifolium afforded in addition to known ones three new prenylated flavanoids, one chalcone and two flavanones.     

Antimicrobial agents from higher plants: Prenylated flavonoids and other phenols from Glycyrrhiza lepidota

Bioassay directed fractionation of extracts of American licorice, Glycyrrhiza lepidota (Leguminosae), resulted in identification of the known bibenzyl, 3,5-dihydroxy-4-(3-methyl-2-butenyl)-bibenzyl, and the known flavanones, glabranin and pinocembrin, as well as the isolation and structure determination of the new flavonol, glepidotin A and the new dihydroflavonol, glepidotin B as antimicrobial agents.     

Flavonoids from Wyethia glabra

Ten flavonoid compounds, including three new natural products, were isolated from a dichloromethane extract of Wyethia glabra. The known compounds are: orobol 7-methyl ether, orobol 3′-methyl ether, naringenin 7-methyl ether, eriodictyol, 8-C-prenyleriodictyol, 6-C-prenyleriodictyol and 8-C-prenylnaringenin. Eriodictyol 7-methyl ether, 2′,4′,6′-trihydroxy-4-methoxychalcone and 6-C-prenylnaringenin are new natural products. An additional prenylated flavanone was isolated and partially characterized.     

Amoradin,amoradicin and amoradinin,three prenylflavanones from Amorpha fruticosa

Three new prenylflavanones, amoradin, amoradicin and amoradinin, were isolated from the root bark of Amorpha fruticosa. Their structures were deduced from chemical and spectral evidence.     

A diterpene,a sesquiterpene quinone and flavanones from Wyethia helenioides

The aerial parts of Wyethia helenioides afforded a new geranyl nerol derivative (a 16-hydroxy-18-oic acid), two isomeric prenylated lavanones and a quinone derived from bisabolene. The structures were elucidated by spectroscopic methods and some chemical transformations. The chemotaxonomic situation is discussed briefly.     

New prenylated isoflavones and a prenylated dihydroflavonol from Millettia pachycarpa

Extraction of Millettia pachycarpa Benth. gave 5,7,4′-trihydroxy-6,8-diprenylisoflavone (1a), 5,7,4′-trihydroxy-6,3′-diprenylisoflavone (2a), 5,7,3′,4′-tetrahydroxy-6,8-diprenylisoflavone (3a) and (2R, 3R)-5,4′-dihydroxy-8-prenyl-6″,6″-dimethylpyrano[2″,3″: 7,6]-dihydroflavonol (4a) whose structures were established by chemical transformations and spectroscopic means. Pectolinarigenin and salvigenin were isolated from Buddleia macrostachya Benth.     

3-Geranyloxy-6-methyl-1,8-dihydroxyanthraquinone and vismiones C,D and E from Psorospermum febrifugum

Three new vismiones and 3-geranyloxy-6-methyl-1,8-dihydroxyanthraquinone were isolated from the berries of Psorospermum febrifugum together with the known chrysophanic acid, 2-isoprenylemodin and ferruginin B. Their structures were established through chemical and spectral means. The occurrence of prenylated anthracenes only in Vismieae suggests their use as systematic markers for the tribe.     

Fungitoxic dihydrofuranoisoflavones and related compounds in white lupin,Lupinus albus

Chromatographic investigation of a methanolic extract of white lupin roots has revealed the presence of six new dihydrofuranoisoflavones (lupinisoflavones A-F). Three monoprenylated (3,3-dimethylallyl-substituted) isoflavones (wighteone, luteone and licoisoflavone A), two diprenylated isoflavones [6,3′-di(3,3-dimethylallyl)genistein (lupalbigenin) and 6,3′-di(3,3-dimethylallyl)-2′-hydroxygenistein (2′-hydroxylupalbigenin)] and two pyranoisoflavones (parvisoflavone B and licoisoflavone B) have also been isolated from the same source. In addition to genistein, leaf extracts of L. italbus contain 3′-O-methylorobol which is presumed to be the precursor of lupisoflavone [5,7,4′-trihydroxy-3′-methoxy-6-(3,3-dimethylallyl)isoflavone]. Probable biogenetic relationships between the prenylated, and dihydrofurano-and pyrano-substituted isoflavones in roots and leaves of L. albus are briefly discussed.