3′-Hydroxypsilotin,a minor phenolic glycoside from Psilotum nudum

A new non-flavonoid glycoside, 3′-hydroxypsilotin {6-[4′-(β-D-glucopyranosyloxy)-3′-hydroxyphenyl]-5,6-dihydro-2-oxo-2H-pyran}, was isolated from Psilotum nudum by droplet counter current chromatography and preparative HPLC. The structure was established by spectroscopic analysis including ¹H and ¹³C NMR and high resolution mass spectrometry.     

Structural studies on a polysaccharide obtained from the cambium layer of a bael (Aegle marmelos) tree

The purified polysaccharide isolated from the cambium layer of a young bael (Aegle marmelos) tree contains galactose, arabinose, rhamnose, xylose, and glucose in the molar ratios of 10.0:9.8:1.4:1.9:1. Methylation analysis and Smith degradation studies established the linkages of the different monosaccharide residues. The anomeric configurations of the various sugar units were determined by oxidation of the acetylated polysaccharide with chromium(VI) trioxide. The oligosaccharides isolated from the polysaccharide by graded hydrolysis were characterized. The structural significance of these results is discussed.     

Muellitol,a novel trialkenyl inositol from Evodiella muelleri

Muellitol has been isolated from the leaves of Evodiella muelleri and the structure established as 1,3,5-tri-(3-methyl-2-butenyl)cyclohexane-r-1-t-2-c-3-t-4-c-5-t-6-hexol. Chemical and spectroscopic examination of the compound and its derivatives showed it to be conformationally similar to scyllitol. This is the first report of the natural occurrence of a triprenylinositol.     

Brickellin,a novel flavone from brickellia veronicaefolia and b. chlorolepis

A new highly oxygenated flavone methyl ether has been isolated from Brickellia veronicaefolia and B. chlorolepis. It has been identified as 5,6′-dihydroxy-6,7,2′,3′,4′-pentamethoxyflavone and given the name brickellin.     

N-methylflindersine from Spathelia sorbifolia

The isolation and taxonomic significance of N-methylflindersine from S. sorbifolia is discussed.     

Carotenoids of Phaffia rhodozyma, a red-pigmented fermenting yeast

The red-pigmented fermenting yeast Phaffia rhodozyma contains astaxanthin as the principal carotenoid pigment. Echinenone, 3-hydroxyechinenone and phoenicoxanthin were also isolated and identified; isocryptoxanthin and canthaxanthin were absent. Evidence is presented for a new carotenoid, 3-hydroxy-3′4′-didehydro-β,ψ-caroten-4-one. A possible biosynthetic scheme for the formation of astaxanthin in P. rhodozyma is suggested.     

Investigations on the structure of a hemicellulose fraction isolated from the trunk of a young bael (Aegle marmelos) tree

Purified hemicellulose isolated from a young bael (Aegle marmelos) tree with 2.5m sodium hydroxide contained d-xylose and 4-O-methyl-d-glucoronic acid in the molar ratio of 7.43:1; traces of glucose, galactose, rhamnose, and arabinose were also present. The linkages between the monosaccharide units were determined by methylation analysis of a hemicellulose fraction (II A) and carboxyl-reduced, hemicellulose II A, and the results were corroborated by those from periodate oxidation and Smith degradation. The anomeric configurations of the d-xylopyranosyl residues were determined by chromium(VI) trioxide oxidation of the acetylated, carboxyl-reduced hemicellulose, and the aldobiouronic acid obtained from graded hydrolysis was characterized. These experiments clearly revealed the structure of this hemicellulose.     

Isofraxinellone,a limonoid lactone from the bark of Fagaropsis glabra

Two lactones, both degraded limonoids, have been isolated from the trunk bark of Fagaropsis glabra. Isofraxinellone is a new natural compound and fraxinellone has previously been characterized in plants of the same family. The structure of isofraxinellone was determined by physical and chemical methods.     

Phylloflavan,a characteristic constituent of Phyllocladus species

Selective visualization of 2D TLC of extracts of Phyllocladus species with vanillin—hydrochloric acid showed a characteristic pattern of constituents attributable to catechin, epicatechin and phylloflavan, a new flavanoid compound. Optical rotation measurements showed that while catechin and epicatechin are of the normal type with the 2R configurations, the flavan moiety in phylloflavan is of the opposite 2S configuration. Spectroscopic data of the new compound and its hydrolysis products showed phylloflavan to be ent-epicatechin-3-δ-(3,4-dihydroxyphenyl)-β-hydroxypentanoate.     

Flavonoids from Erythroxylon argentinum

Quercetin 3-rutinoside, quercetin 3-α-l-rhamnoside, 7,4′-dimethylquercetin 3-rutinoside and the novel glycoside 7,4′-dimethylquercetin 3-rutinoside-5-glucoside have been identified from aerial parts of Erythroxylon argentinum.     

Coumarins of Skimmia japonica

The coumarins, isoimperatorin, isomeranzin, meranzin hydrate, oxypeucedanin, oxypeucedanin hydrate, oxypeucedanin methanolate and umbelliferone and the triterpene, friedoolean-14-en-3β-ol (taraxerol) were isolated from leaves of Skimmia japonica.     

Furanocoumarin biosynthesis in Ruta graveolens cell cultures

The biosynthetic routes to four linear furanocoumarins—psoralen, xanthotoxin, bergapten. isopimpinellin-co-occurring in Ruta graveolens cell cultures have been investigated with six ¹⁴C-labelled compounds. Mevalonic acid was only poorly incorporated, in contrast to umbelliferone. In support of previous suggestions, 7-demethylsuberosin and (±)-marmesin were very good precursors of the linear furanocoumarins. 7-O-Prenylumbelliferone also was fairly well utilized, but this was probably owing to a prior ether cleavage yielding umbelliferone. Psoralen was well incorporated into bergapten and xanthotoxin, but not into the dimethoxylated isopimpinellin. Differences exist between the organized plant and its cell culture in terms of metabolic products and, by implication, precursor utilization. S(+)-Marmesin was obtained in small quantity from an acid-hydrolysable conjugate present in the culture medium. Syntheses of [2-¹⁴C]7-demethylsuberosin, [2-¹⁴C]osthenol, [2-¹⁴C]7-O-prenylumbelliferone, [3-¹⁴C] (±)-marmesin, and [3-¹⁴C]psoralen are described, as well as an improved method for separation of furanocoumarin mixtures by TLC and GLC.     

Metabolism of limonoids via a deoxylimonoid pathway in Citrus

Methyl deacetylnomilinate was metabolized in leaves of calamondin (Citrus microcarpa) to form a deoxy derivative. This reaction indicated the presence in citrus of an epoxidase, which is required for the first step of the deoxylimonoid pathway. The product of the second step, deoxylimonic acid, was isolated from grapefruit seeds. Deoxylimonate A-ring lactone hydrolase, which is involved in the third step of the deoxylimonoid pathway, was also found in grapefruit seeds. These results and the previously reported presence of the first metabolite of this pathway, deoxylimonin, show that limonoids are metabolized in citrus, not only via the 17-dehydrolimonoid pathway as previously established, but also via the deoxylimonoid pathway.     

Coumarins from unripe fruits of Poncirus trifoliata

Petrol extracts of unripe fruits of Poncirus trifoliata L. were found to contain 7-geranyloxycoumarin, bergapten, imperatorin, 6-methoxy-7-geranyloxycoumarin and two new coumarins which were shown by chemical and spectroscopic means to be 7-(3′-methyl-2′,3′-epoxybutyloxy)-8-(3″-methyl-2″,3″-epoxybutyl)coumarin and 7-(3′-methyl-2′,3′-epoxybutyloxy)-8-(3″-methyl-2″-oxobutyl)coumarin respectively.     

Isoflavones from Dipteryx odorata

Five isoflavones have been isolated from the heartwood of Dipteryx odorata: retusin, retusin 8-methyl ether, 3′-hydroxyretusin 8-methyl ether, odoratin (7,3′-dihydroxy-6,4′-dimethoxyisoflavone) and dipteryxin (7,8-dihydroxy-6,4′-dimethoxyisoflavone).     

Biosynthesis of obacunone from nomilin in Citrus limon

Radioactive tracer work showed that [¹⁴C]nomilin was converted to at least four metabolites in Citrus limon. One metabolite was identified as obacunone, showing that obacunone is biosynthesized from nomilin in C. limon.     

Effect of oleocellosis,desiccation, and fungal infection upon the terpenes of individual oil glands in Citrus latipes

Mono- and sesqui-terpenes of individual oil glands of Citrus latipes fruits were analyzed for their homogeneity. The effect of oleocellosis, desiccation, Penicillium and Phytophthora infection upon the individual terpene components was investigated and expressed in a discriminant analysis and in canonical variables. Each oil gland contained the entire spectrum of terpenes specific for each species, and the biggest difference in affected glands was due to Penicillium infection.     

Alkaloids of Zanthoxylum monophyllum and Z. punctatum

The known alkaloids N-methylcorydine and magnoflorine were major constituents of stems and branches of Zanthoxylum punctatum (Rutaceae). Berberine was the major alkaloid of Z. monophyllum, which also contained a new pyrano-2-quinolone alkaloid, zanthophylline, and its desmethyl analog. Zanthophylline has an —NCH₂OAc functional group which is readily hydrolyzed by dilute acid. Methyl vanillate and the furocoumarin columbianetin were also found in Z. monophyllum.