Naphthoquinones from Euclea pseudebenus

Diospyrin, isodiospyrin, 8′-hydroxydiospyrin, racemic 8′-hydroxyisodiospyrin and two other naphthoquinones have been isolated from Euclea pseudebenus. Euelein is recognized to be identical to diospyrin.     

Eucleolatin: A dimeric methylnaphthazarin from Euclea lanceolata

8,8′-Dihydroxy-4,4′-dimethoxy-6,6′-dimethyl-2,2′-binaphthyl-1,1′-quinone, 7-methyljuglone, 8′-hydroxydiospyrin, and eucleolatin have been isolated from the root bark of E. lanceolata. Eucleolatin is the 3,6′or 3,7′- dimer of 2-methylnaphthazarin.     

A pentacyclic quinone diosindigo B from the heartwood of Diospyros melanoxylon

Diosindigo A, diosindigo B and biramentacéone have been isolated from heartwood of Diospyros melanoxylon. A violet pigment isolated from the same source has been shown to be a new pentacyclic quinone. Sunlight causes diosindigo B to change to the pentacyclic quinone and biramentacéone. The intense peaks at m/e 389 and 388 in the mass spectrum of diosindigo B are doublets which arise by fragmentation of both M⁺ and M⁺ + 2.     

Nonadecan-7-ol-2-one an aliphatic ketol from Diospyros peregrina

A new aliphatic ketol isolated from the stems of Diospyros peregrina was characterized as nonadecan-7-ol-2-one by analyses MW determination chemical degradation and spectroscopic data.     

Triterpenoid,coumarin and quinone constituents of eleven Diospyros species (Ebenaceae)

From the bark and/or timber extracts of Diospyros hirsuta, D. moonii, D. quaesita, D. spinescens, D. thwaitesii and D. walkeri, the following compounds have been isolated; lupeol, betulin, betulinic acid sitosterol, taraxerol, taraxerone, ursolic acid, oleanolic acid scopoletin, plumbagin, elliptinone, diospyrin and diosindigo A. TLC examination of the bark and timber extract of D. acuta, D. chaetocarpa, D. oblongifolia, D. oppositifolia and D. rheophytica is reported. Lupeol betulin, oleanolic acid and sitosterol have been isolated from the fruit of D. oblongfolia.     

A new dihydrobenzofuran from Liatris provincialis

A chloroform extract of Liatris provincialis Godfrey gave as a minor component a new dihydrobenzofuran, whose structure was established as I.     

Naphthoquinones and triterpenes from some asian Diospyros species

Investigation of the stem bark, wood and/or fruit of nine Asian Diospyros spp. (Ebenaceae) has revealed a range of triterpenes and naphthoquinones     

Raimondal,a new sesquiterpenoid from pigment glands of Gossypium raimondii

A new sesquiterpenoid isolated from pigment glands of leaves and immature bolls of Gossypium raimondii has been named raimondal and identified as 5-iso-propyl-2-methoxy-3-methyl-1,6,7-trihydroxy-8-naphthaldehyde. Raimondal was oxidized by ferric chloride to o-hemigossypolone (8-formyl-5-iso-propyl-3-methyl-6,7-dihydroxy-1,2-naphthoquinone) which was readily reduced to its hydroquinone, 2-hydroxyhemigossypol. Neither of the two oxidation products were detected in extracts from G. raimondii.     

Structure and biosynthesis of 5-deoxyfusarubin and anhydro-5-deoxyfusarubin,naphthaquinone pigments from Nectria haematococca

Two naphthaquinone pigments, 5-deoxyfusarubin and anhydro-5-deoxyfusarubin, were isolated from a yellow strain of the fungus Nectria haematococca. The ¹³C NMR spectra of 2 biosynthetically labelled from [1-¹³C]acetate confirmed the structures of the pigments and established the heptaketide origin of the molecules.     

A new cinnamaldehyde from Patagonula americana

The heartwood of Patagonula americana contains 3-hydroxy-2,4,5,6-tetramethoxy-trans-cinnamaldehyde (patagonaldehyde).     

A new triterpene lactone from Gymnocladus dioica

2β,23-Dihydroxyacacic acid lactone was isolated from Gymnocladus dioica as an artifact from 2β, 3β 16β, 21β, 23-pentahydroxyolean-12-ene-28-oic acid.     

Naphthoquinones and triterpenes from african Diospyros species

Investigation of the bark and/or wood of seventeen African species of Diospyros has revealed the presence of a number of triterpenes and naphthoquinones. The triterpenes lupeol, betulin and betulinic acid were detected in all samples but three other triterpenes were each found in only one species; betulinaldehyde in D. canaliculata, cerin in D. iturensis, and glutinol in D. zenkeri. Naphthoquinones were detected in fourteen of the seventeen species and the common dimeric compounds diospyrin, isodiospyrin and diosindigo-A were isolated. D. canaliculata differed from all other species in producing derivatives of plumbagin including its reduced form, isoshinanolone (1R,2R) and a novel stereoisomer which was given the trivial name epiisoshinanolone (1S,2R).     

Rhusflavone: A new flavanoflavone from Rhus succedanea

From the drupes of Rhus succedanea has been isolated a new flavanoflavone, rhusflavone, which has the structure 6,8″-naringeninylapigenin.     

Carotenoid changes in the peel of ripening persimmon (Diospyros kaki) cv Triumph

The changes of the carotenoid pigments in the peel of ripening persimmon (Diospyros kaki) cv Triumph were followed for an entire season. During ripening, the total carotenoid decreased until colour break, then increased gradually and drastically at the last ripening stages. The chloroplast carotenoid pattern of the unripe fruit changed into a chromoplast pattern in which cryptoxanthin was the predominant pigment, reaching a level between 40 and 50% of the total carotenoids. It accumulated continuously at a rate of approximately 10% at each 2 week interval, its percentage being characteristic for each ripening stage. Other major pigments at levels of approximately 10% of the total carotenoids were zeaxanthin, antheraxanthin and violaxanthin. In the fully ripe fruit, ripened both on and off the tree, lycopene which was not present before was found as the second major pigment. This unusual pattern change is discussed.     

A new alkaloid from Voacanga chalotiana

The structure of 3-hydroxyvoachalotine, a new indole alkaloid isolated from the root bark of Voacanga chalotiana, has been determined by spectroscopic analysis and by chemical correlation with voachalotine.     

A new flavone from Ageratum conyzoides

A new flavone has been isolated from Ageratum conyzoides and identified as 5,6,7,8,3′,4′,5′-heptamethoxyflavone on the basis of spectroscopic and degradative evidence and the assignment is confirmed by synthesis.