Proanthocyanidin glycosides and related polyphenols from cacao liquor and their antioxidant effects

Purification of polar fractions from cacao liquor extracts gave 17 phenolics including four new compounds. The new compounds were characterized as a C-glycosidic flavan, an O-glycoside of a dimeric and two O-glycosides of trimeric A-linked proanthocyanidins, on the basis of spectroscopic data. Isolated polyphenols showed inhibitory effects on nicotinamide adenine dinucleotide phosphate-dependent lipid peroxidation in microsomes and on the autoxidation of linoleic acid. These effects were attributed to the radical-scavenging activity in the peroxidation chain reactions, based on the findings that the cacao polyphenols effectively scavenged the 1,1-diphenyl-2-picrylhydrazyl radical.     

Volatile components of cocoa with particular reference to glucosinolate products

The aroma volatiles of raw, fermented and roasted cocoa beans were extracted and concentrated to valid essences using well-established techniques. Analysis by GC and GC/MS showed at least 84 components of which 13 were identified for the first time as cocoa volatiles. In total, ca 5,66 and 65 μg of aroma components were obtained per g of raw, fermented and roasted cocoa beans, respectively. The most abundant groups of volatiles from fermented beans were alcohols (ca40%w/w of the total volatiles) and esters (ca 32%), whilst those from roasted beans were pyrazines (ca 40%) and aldehydes (ca 23%). Trimethyl- and tetramethylpyrazine were also detected in fermented beans, and it is suggested that they contribute to the noticeable cocoa/chocolate aroma of fermented unroasted beans. Phenylacetonitrile, benzyl isothiocyanate and benzyl thiocyanate were all identified amongst cocoa volatiles, together showing the presence of precursor benzylglucosinolate in cocoa. Glucosinolate products were detected in roasted beans, and it seems likely that the enzyme thioglucoside glucohydrolase survived the conditions of roasting. Benzyl thiocyanate was detected only in raw beans, showing that the glucosinolate ‘thiocyanate–forming factor’ did not withstand conditions of fermentation     

Coumarins from the heartwoods of Mansonia gagei Drumm.

Three coumarins and three known mansonones were isolated from the heartwood of Mansonia gagei Drumm. The structures of the three coumarins were elucidated as 3,8-dimethyl-5-isopropyl-6-methoxycoumarin (mansonrin A) 3,8-dimethyl-5-isopropyl-6-hydroxycoumarin (mansorin B) and 2,3-dihydro-3,6,9-trimethyl naphtho[1,8-bc]pyran-7-oxa-8-one (mansorin C) by analyses of physical properties and spectroscopic data. The cytotoxicity of the isolated compounds against brine shrimp Artemia salina Linn. was also evaluated.     

On the Systematic Position of Paradombeya Stapf

The systematic position of Paradombeya Stapf has been debated until now. The studies on gross morphology, anatomy, palynology and cytology were undertaken to confirm the systematic position and affinities of this genus. The combination of features, e. g., umbel-like cyme, 2-celled anther, presence of staminodes, staminal tube, 15 stamens, bifid cotyledons, wood anatomy, chromosome number of 2n=20, triporate, spiny and spheroidal pollen grains, suggests that the genus be better placed in the tribe Dombeyeaeof the Sterculiaceae.     

Anthocyanins of the Sterculiaceae

No uncommon anthocyanins were detected among 13 taxa (sig genera) of the Sterculiaceae. Floral pigments appear to be of little systematic utility in this family.     

New cyclopeptide alkaloids from Melochia tomentosa

Scutianine B and two new cyclopeptide alkaloids, melonovines A and B have been isolated from Melochia tomentosa.