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.     

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.     

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.     

Flavonoids from Tephrosia fulvinervis

From the pods of Tephrosia fulvinervis, a new Ethiopian species, a new flavanone, fulvinervin A, and a new flavone, fulvinervin B, have been isolated and their structures elucidated from their chemical properties and spectral data.     

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.     

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.     

Thonningine-A and thonningine-B: two 3-phenylcoumarins from the seeds of Millettia thonningii

The seeds of Millettia thonningii have yielded four isoflavones and three 4-hydroxy-3-phenylcoumarins, of which two are novel. On the basis of spectral analyses the novel compounds have been identified as 4-hydroxy-5,8-dimethoxy-3-(3′,4′-methylenedioxy)phenyl-2″-isopropenylfurano (4″,5″:6,7)coumarin (thonningine-A) and 4-hydroxy-5,8-dimethoxy-3-(4′-methoxy)phenyl-2″-isopropenylfurano(4″, 5″: 6,7)coumarin (thonningine-B).     

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.     

Flavanones and xanthones from Maclura pomifera

(+-)Euchrestaflavanones B and C and 8-prenyltoxyloxanthone C have been isolated from the root bark of Maclura pomifera. A study of the cyclization of alvaxanthone under varying conditions is reported.     

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.     

Flavonoids from the seeds of Lonchocarpus costaricensis

Seven flavonoids have been isolated from the seeds of Lonchocarpus costaricensis of which four appear to be novel. The new compounds have been identified as the β-hydroxychalcone demethylpraecansone-B and the flavanones 7-(3,3-dimethylallyloxy)-8-(3-hydroxy-3-methyl-trans-but-1-enyl)flavanone, 7-(3,3-dimethylallyloxy)-8-(3,3-dimethylallyl)-5-methoxyflavanone and 8-(3,3-dimethylallyl)-5,7-dimethoxyflavanone.     

Pterocarpans of Neorautanenia edulis and N. Amboensis

The root bark of Neorantanenia edulis and N. amboensis yielded six new natural pterocarpanoids, the structures of which have been determined mainly by physical methods and by partial syntheses. They include edulane, edudiol, neoraucarpan, neorautanin, edulenol, and neoraucarpanol.     

Flavonoids and coumarins from Platymiscium praecox

The wood of Platymiscium praecox Mart. (Leguminosae-Lotoideae) contains sitosterol, 4,2′,4′-trihydroxychalcone, (2R)-7-hydroxyflavanone, (±)-7,4′-dihydroxyflavanone, (2S, 3S)-3,7-dihydroxyflavanone, 3,7-dihydroxyflavone, 3,7,4′-trihydroxyflavone, 6,7-dihydroxy-4′-methoxyisoflavone and 6,7-dimethoxycoumarin. It also contains three novel compounds: 7-hydroxy-4-methoxy-5-methylcoumarin, 7-O-glucosyloxy-4-methoxy-5-methylcoumarin and 7-hydroxy-4,8-dimethoxy-5-methylcoumarin.     

Isoflavones from Xanthocercis zambesiaca

In addition to the previously described 7-hydroxy-8,4′-dimethoxy- and 7,3′-dihydroxy-8,4′-dimethoxy-isoflavone the heartwood of Xanthocercis zambesiaca has been shown to contain 7-hydroxy-8,3′,4′-trimethoxy-,3′,4′-dimethoxy-6,7-methylenedioxy- and 8,3′,4′-trimethoxy-6,7-methylenedioxy-isoflavone. A technique of determining isoflavone hydroxylation patterns by deuterium labelling is described.     

Structures of some minor pterocarpans of Neorautanenia edulis

The constitution of five new compounds, (?)-neorautenol, (?)-neodunol, (?)-homoedudiol, neorauteen and neoduleen, has been established in the root bark of Neorautanenia edulis.     

Two isoprenylated isoflavone phytoalexins from Cajanus cajan

Four phytoalexins were isolated from sliced seeds of pigeonpea which had been incubated with its native microflora. Two were identified as the known pigeonpea phytoalexins, cajanin and cajanol, and the other two were characterized as new isoprenylated isoflavones.     

Tirumalin,a new prenylated dihydroflavonol from Rhynchosia cyanosperma

A new dihydroflavonol has been isolated together with the known flavonol-O- glycosides, rutin and kaempferol-3-rutinoside, and (+)-pinitol from the leaves of R. cyanosperma Benth. The dihydroflavonol was identified as (+)-(2R, 3R)-8-C-prenyltaxifolin-7, 4′-dimethyl ether on the basis of spectroscopic studies and the compound given the trivial name tirumalin.