Stanley Z. Dziedzic

Phenolic acids and related compounds as antioxidants for edible oils

Abstract A series of hydroxy aromatic acids, esters and lactones have been evaluated as antioxidants for lard at 120°C at 0·025%, 0·05% and 0·1% concentrations. Most of the compounds studied are direct biochemical precursors of chalcones and these, in turn, of various flavonoids commonly occurring in plant material. Antioxidant efficiency has been shown to be very dependent on the number of phenolic hydroxyl groups in the molecule and also to be promoted by steric hindrance. Cinnamic acids are more effective than corresponding benzoic acids, and phenylacetic and phenylpropionic acids are even more effective. 3,4-Dihydroxy chalcone is more effective than the analogous caffeic acid. In general, the presence of a carbonyl group in the molecule appears to be necessary in this series for a high level of antioxidant activity.

Polyhydroxy chalcones and flavanones as antioxidants for edible oils

Abstract A series of 11 polyhydroxy chalcones, and in 4 cases, flavanones derived from them by isomerisation, some of which occur naturally in plant tissues, have been shown to be potent antioxidants for lard. Most of these compounds, not being commercially available, were prepared synthetically. Two of them, 3′,3,4-trihydroxy- and 2′4′,2,3-tetrahydroxy chalcone, are described for the first time. 3,4-Dihydroxy chalcones, such as butein and okanin, are particularly effective antioxidants in the range of concentrations 0·025–0·1%, as judged by induction period measurements. Chalcones are more effective than the corresponding flavanones. The hypothesis is put forward that the effectiveness of 3,4-dihydroxy chalcones is dependent on the formation of extended forms of resonance-stabilised free radicals.

Puerarin 6″-O-β-apiofuranoside, a C-glycosylisoflavone O-glycoside from Pueraria mirifica

Abstract In addition to puerarin (7,4′-dihydroxyisoflavone 8- C -β-glucopyranoside), the air-dried tuberous roots of Pueraria mirifica have been found to contain a second, previously unreported, isoflavone C -glycoside. This new compound (mirificin), which has now been identified by chemical and spectroscopic (UV, 1 H NMR, 13 C NMR including GASPE) procedures as puerarin 6″- O -β-apiofuranoside is the first O″ -glycoside of an isoflavone C -glycoside to be discovered in nature. Mirificin contains a rare 1 → 6 interglycosidic linkage between apiose and the glucose unit which is unique in flavonoids. It is proposed that 1 → 2 and 1 → 6 linked apioglucosides can be distinguished by 1 H NMR spectroscopy in the same manner as used for the equivalent rhamnoglucosides.

Saponins and sapogenins of chick pea, haricot bean and red kidney bean

Abstract The saponins of red kidney bean ( Phaseolus vulgaris ), chick pea ( Cicer arientinum ) and haricot bean ( Phaseolus vulgaris ) all contain soyasapogenol B as the only aglycone. The levels of soyasapogenol B estimated were: chick pea, 0·075%; haricot bean, 0·149%; and red kidney bean, 0·102%; on a defatted, dry weight basis. HPLC separation of the saponin preparations indicates the presence of at least five saponins in red kidney bean, five in haricot bean and two in chick pea. Retention time comparison of the saponin preparations indicates the possible presence of soyasaponin I in all three legumes and soyasaponin II in haricot and red kidney beans.

Isoflavones from pods of Laburnum anagyroides

Abstract The known isoflavones, genistein, 5- O -methylgenistein, wighteone, luteone and alpinumisoflavone, have been isolated from methanol extracts of Laburnum anagyroides pods. The pod extracts also yielded three new isoflavones; anagyroidisoflavone A (5,4′-dihydroxy-(3″,4″-dihydro-3″-hydroxy-4″-methoxy)-2″,2″-dimethylpyrano (5″,6″:6,7)isoflavone), anagyroidisoflavone B (5,4′-dihydroxy-(3″,4″-dihydro-3″,4″-epoxy)-2″,2″-dimethylpyrano (5″,6″:6,7)isoflavone) and laburnetin (5,7,4′-trihydroxy-6-(2″-hydroxy-3″-methyl-3″-butenyl)isoflavone). The structures of the new compounds were determined by spectral analyses.

Coumestans from the roots of pueraria mirifica

Three isoflavonoids obtained from a methanolic extract of Pueraria mirifica roots have been identified as 3,9-dihydroxy-8-methoxy-7-(3,3-dimethylallyl)-coumestan (mirificoumestan), 3,9-dihydroxy- 8-methoxy-7-(3-hydroxy-3-methylbutyl)-coumestan (mirificoumestan hydrate), and 3,9- dihydroxy-8-methoxy-7-(2,3-dihydroxy-3-methylbutyl)-coumestan (mirificoumestan glycol). These new coumestans co-occur with coumestrol (3,9-dihydroxycoumestan), a compound already found in P. mirifica roots

A chemical investigation of Pueraria mirifica roots

Ten isoflavonoids including daidzein, daidzin (daidzein-7-O-glucoside), puerarin (daidzein-8- C-glucoside), genistein and coumestrol have been isolated from a methanolic extract of Pueraria mirifica roots. Apart from these known compounds and mirificin, a novel apioside derivative of puerarin, the roots have also been found to contain three minor coumestans and one 5-deoxyisoflavone for which only limited spectroscopic data are currently available.

Minor Isoflavones from the Roots of Pueraria mirifica

The isoflavone aglycone kwakhurin hydrate, and the glycosides genistin (genistein-7-Oglucoside) and puerarin-6′′-monoacetate have been isolated from a methanolic extract of Pueraria mirifica roots.

Synthesis and taste properties of maltose and maltitol analogues

Abstract The hypothesis that intramolecular hydrogen bonding is responsible for the sweetness of maltitol is tested by the synthesis of maltitol analogues which differ in configuration at C″ 3 and C′ 4 and sensory evaluation of the products. 3- Allo -maltitol and galacto maltitol were synthesised by treating suitably protected methanesulphonylated derivatives of benzyl β-maltoside with sodium benzoate followed by removal of the blocking groups and subsequent reduction with sodium borohydride. Sensory evaluation of maltose, maltitol and their analogues revealed that the non-reducing end is involved in the generation of the sweet response and that intramolecular hydrogen bonding governs the accession of this class of polyol sweeteners to the receptor site on the tongue.

Structure Elucidation of Kwakhurin, a New Prenylated Isoflavone from Pueraria miriflca Roots

Abstract An isoflavonoid obtained from dried roots of the Thai legume Pueraria mirifica has been identified by chemical and spectroscopic methods as 7,2′,4′-trihydroxy-5′-methoxy-6′-(3,3-dimethylallyl)isoflavone (kwakhurin).