Luteone

Phytochemistry,1976,15(10):1485-7.

The isopentenyl isoflavone luteone as a pre-infectional antifungal agent in the genus Lupinus[Reference: WebLink]

The prenylated isoflavone Luteone has been isolated from healthy leaves of Lupinus albus and 11 other lupin species.
METHODS AND RESULTS:
Evidence is presented that this compound occurs as a leaf surface constituent. In vitro tests indicate that Luteone and a second unidentified isoflavone frorn L. albus possess antifungal activity sufficient to support their proposed role as pre-infectional resistance factors.
CONCLUSIONS:
No evidence was obtained to suggest that phytoalexins were produced by the fungus-infected leaves of L. albus.

J Ethnopharmacol . 2016 Jun 5;185:171-81.

Antimicrobial and antioxidant activity and chemical characterisation of Erythrina stricta Roxb. (Fabaceae)[Pubmed: 26969405]

Abstract Ethnopharmacological relevance: The bark of Erythrina stricta Roxb. (Fabaceae) has been used in Indian indigenous systems as a remedy for rheumatism, stomach-ache, asthma, dysentery, contact dermatitis, eczema and skin infections. However, there have been limited phytochemical or biological studies on the bark of E. stricta and there are no studies that align with its traditional medicinal uses. Aim of the study: The aim of this study was to assess the antimicrobial and antioxidant activity of the stem bark of E. stricta to support its topical use in the treatment of contact dermatitis, eczema and skin infections and to isolate and identify any bioactive compounds. Materials and methods: MTT microdilution and disc diffusion assays were used to determine the antimicrobial activities of n-hexane, dichloromethane, ethyl acetate, methanol and water extracts of the bark of E. stricta. Column and preparative thin layer chromatography were used for the purification of the dichloromethane extract. The structures of the compounds isolated were elucidated by extensive 1D and 2D NMR spectroscopic techniques and comparison with published data. The antioxidant activities of the extracts were determined by DPPH free radical scavenging and FRAP assays and the antioxidant activity of the pure compounds by dot-blot and DPPH staining methods. Results: The dichloromethane, ethyl acetate, and n-hexane extracts showed the most significant activity with MIC values of 7.8μg/mL, 125μg/mL, and 125μg/mL against a sensitive strain of Staphylococcus aureus. The dichloromethane and ethyl acetate extracts also showed significant activity against Candida albicans with MIC values of 125μg/mL and 1mg/mL respectively. GC-MS analysis of the n-hexane extract showed the presence of the antibacterial and antifungal compounds β-caryophyllene, caryophyllene oxide, α-selinene, β-selinene, selin-11-en-4-α-ol, α-copaene and δ-cadenine. Phytochemical studies of the dichloromethane extract led to the isolation of the novel compound erynone (1), together with six known compounds; wighteone (2), alpinum isoflavone (3), Luteone (4), obovatin (5), erythrinassinate B (6) and isovanillin (7). Luteone (4) exhibited the most significant antibacterial activity with minimum inhibitory quantity (MIQ) values of 1.88μg, 1.88μg and 3.75μg, respectively, against sensitive (MSSA) and resistant strains (MRSA and MDRSA) of S. aureus using a TLC bioautography assay. Erynone (1) exhibited the greatest DPPH free radical scavenging activity. Conclusions: Seven compounds, including a new chromanone, were isolated from the antimicrobial dichloromethane extract of the stem bark of E. stricta. Six of the seven compounds showed antibacterial and/or antioxidant activities. These findings provide support for the customary (traditional and contemporary) use of E. stricta bark for the treatment of skin and wound infections. Keywords: Alpinum Isoflavone (PubChem CID: 54901393), Isovanillin (PubChem ID: 12127); Antimicrobial; Antioxidant; Chemical constituents; Erythrina stricta; Isoflavanone; Luteone (PubChem CID: 5281797); Obovatin (PubChem CID: 13940733); Wighteone (PubChem ID: 5281814).

J Nat Prod. 2010 Jul 23;73(7):1254-60.

LC-MSMS profiling of flavonoid conjugates in wild Mexican lupine, Lupinus reflexus.[Pubmed: 20568784]

METHODS AND RESULTS:
Profiles of flavonoid conjugates present in the root and leaf tissues of the Mexican wild lupine, Lupinus reflexus, were established using two LC-MSMS systems in the positive and negative ion modes. The ion trap mass spectrometer and quadrupole time-of flight instrument provided sequential MS(n) spectra and MSMS spectra with accurate m/z values of [M + H](+) and [M - H] (-) ions, respectively. Sixty-two flavone and isoflavone glycoconjugates were found and tentatively identified. Numerous isomeric or isobaric compounds with the same molecular mass could be differentiated. Isomeric di- and mono glucosides of biochanin A, genistein, 2'-hydroxygenistein, Luteone, and 2,3-didehydrokievitone were distinguished on the basis of relative abundances of product ions.
CONCLUSIONS:
The studied flavonoid glycoconjugates were acylated with dicarboxylic aliphatic acids and their methyl esters at either the aglycone or glycosidic moiety.

Chem Pharm Bull (Tokyo). 2004 Nov;52(11):1285-9.

Regioselective synthesis of 6-alkyl- and 6-prenylpolyhydroxyisoflavones and 6-alkylcoumaronochromone derivatives.[Pubmed: 15516747]

METHODS AND RESULTS:
The palladium-catalyzed coupling reaction of 6-iodoisoflavone, prepared from 3'-iodoacetophenone derivative, with 2-methyl-3-butyn-2-ol gave 6-alkynylisoflavone derivative, which was hydrogenated to give 6-alkylhydroxyisoflavone (Luteone hydrate) (2). Dehydration of 2 gave 2',4',5,7-tetrahydroxy-6-prenylisoflavone (Luteone) (1). Wighteone hydrate (3) was also synthesized from 6-iodotris(benzyloxy)isoflavone in a similar manner. 6-Alkyl-4'5,7-trihydroxy-coumaronochromone (4) was synthesized by oxidative cyclization of 2 with o-chloranil.