Homoisoflavanones isolation

Du Toil et al. (2007) determinated the antibacterial activity of thirteen homoisoflavanones isolated from six Hyacinthaceae species against Staphylococcus aureus. They also developed a set of physicochemical parameters that would describe antibacterial activity for these and future compounds. Stepwise multiple linear regression analysis of the data yielded a statistically significant two-component model (R = 0.81, p < 0.003). 

Homofolic acid, 5,11-methenyl-tetrahydro-biological activity, 3, 327 Homofolic acid, tetrahydro-biological activity, 3, 327 Homoisoflavanones occurrence, 3, 722 thermoisomerization, 3, 722 thermolysis, 3, 728 Homolytic reactions heterocyclic compounds reviews, 1, 74 Homophthalic acid isocoumarins synthesis from, 3, 830 synthesis, 3, 830 Homophthalic anhydride isochroman-l-one synthesis from, 3, 860 20a-Homoporphyrin nomenclature, 1, 30 Homopterocarpin isolation, 4, 998 ( )- D- Homotestosterone synthesis, 1, 453 Homer-Emmons reaction chromene synthesis by, 3, 749 Hortiacine isolation, 3, 149 Hortiamine isolation, 3, 149... 

Scilla natalensis Planch, [lukhovu, slangkop] (Hyacinthaceae) bulb decoction is nsed for medical cnrrethage and waist or back pain (18,26). The bnlb contains alkaloids, flavonoids, polyphenols, saponins and terpenoids (18). Homoisoflavanones, 5,7-dihydroxy-6-methoxy-3 -(4-hydioxybenzyl)chroman-4-one and 5,7-dihydroxy-3-(3-hydroxy-4-methoxybenzyl)chroman-4-one have also been isolated from the bulb (43). 

The homoisoflavanones belong to a small family of natural products whose first member was isolated by Boehler and Tamm in 1967 from bulbs of Eucomis bicolor Bak. (9). Their discovery resulted from a systematic chemical analysis of Liliaceae for cardiac glycosides. However, unlike the botanically closely related Urginea maritima (L.) Bak. (Squill) and some species of Scilla, Ornithogalum and Dipcadi 33), Eucomis plants did not contain even traces of these compounds. 

The isolation of the homoisoflavanones was simplified to a great extent by the observation that these phenolic compounds are accumulated specifically in a waxy layer between the storage leaves of the bulb. 

Another source of homoisoflavanones is Scilla scilloides Druce. Kouno et al. (44) have described the isolation and identification of 3,9-dihydro-eucomnalin along with the structurally related compounds scillascillin and 2-hydroxy-7-0-methylscillascillin. The new structural feature of these substances is a 3-spirocyclobutene ring system. The name scil-lascillins was adopted for this group of compounds. 

The chemical and physical properties of the homoisoflavanones and of further metabolites isolated from Eucomis spp. have been summarized earlier by Tamm (69) and Ziegler and Tamm (82). 

The natural homoisoflavanones which are saturated at C-3 are optically active (Table 1). The 3-benzylchroman-4-ones show negative rotation values. The only exception so far is 3,9-dihydroeucomin (6) from E. bicolor (Md = +38°) whose dimethyl derivative ([a]o = +12°) is enantiomeric to the analogous compound prepared from ( —)-4-demethyl-5-0-methyl-3,9-dihydroeucomin (8) isolated from E. comosa (26, 27, 38). 

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