Structure of 22-deoxocucurbitacins isolated fromBryonia alba andEcbalium elaterium

22-Deoxocucurbitacin D (II), dihydrocucurbitacin B, cucurbitacin L, and the previously unknown rhamnoglucosyl-22-deoxo-16,23-epoxycucurbitosides A (III) and B (IV) have been isolated from the roots ofBryonia alba and identified. Glucoside (III) has also been identified in the fruit ofEcbalium elaterium L.A. L. Mndzhoyan Institute of Fine Organic Chemistry, Academy of Sciences of the Armenian SSR, Erevan, Translated from Khimiya Prirodnyk Soedinenii, No. 5, pp. 679–687, September–October, 1985.     

Lipids ofSilene brahuica

The qualitative and quantitative compositions of the lipid complex of the epigeal part ofSilene brahuica Boiss. (family Caryophyllaaceae) have been studied. The fatty acid composition of the acyl-containing lipids has been determined. Some differences have been found in the compositions of the fatty acids of the neutral lipids and the phospholipids.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 512–514, July–August, 1993.     

Lipids of the biomass ofRuta graveolens, grownin vivo andin vitro

A lower content of chlorophylls, phospholipids, and linolenic acid and a higher content of rutin, carotenoids, and xanthophylls in the biomass ofRuta graveolens L. obtainedin vitro has been found as compared with these indices from the epigeal part of the plant grownin vivo.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent. Institute of Botany, Academy of Sciences of the Republic of Uzbekistan, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 651–655, September–October, 1993.     

Lipids of the tuberous roots ofMandragora turcomanica

The lipids of the tuberous roots ofMandragora turcomanica Mizger (fam. Solanaceae) have been characterized for the first time. By using CC, TLC, Ag⁺-TLC, UV and IR spectroscopies and mass spectrometry, 20 classes of lipids and lipophilic substances have been characterized. The main components of the acyl-containing lipids that were isolated were found to be triacylglycerols and glycolipids, and among the lipophilic compounds they were alkanols and sterols; in the mixture of fatty acids of the acyl-containing lipids the 18:2, 18:1, and 16:0 acids predominated.Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 615–623, September–October, 1994.     

Lipids of microalgae. I. Lipids and a protein hydrolysate fromMonochrysis lutheri

The class composition and the total fatty acid composition of the readily- and difficulty-extractable lipids and the amino acid composition of a protein hydrolysate of the dry biomass from the golden-yellow microalgaMonochrysis lutheri have been determined for the first time. It has been established that the difficulty-extractable lipids differ sharply from the readily extractable lipids in the composition of the neutral and glycolipid components and also in that of the fatty acids; 27% of the weight of the fatty acids of the latter is composed of the 20:4 and 20:5 species. The protein hydrolysate ofM. lutheri contains almost the whole set of essential fatty acids.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbekistan Republic, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 507–511, July–August, 1993.     

Lipids of the oils of the fruit and leaves ofHoppopha? rhamnoides

The analysis of some lipids of four forms of the common sea buckthorn has shown that they all differ with respect to the composition of the fatty acids of the triacylglycerols of the leaves. One of the forms is characterized by an infringement of the specificity of the composition of the fatty acids in positions 2 of the triacylglycerols of the oils of the seeds and the leaves.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. V. L. Komarov Institute of Botany, Academy of Sciences of the Azerbaidzhan SSR, Baku. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 710–715, November–December, 1981.     

Lipids of microalgae. III. Lipids of the biomass ofMonocrysis lutheri grown under the conditons of an accumulation culture

The class composition of the lipids of the biomass of the microalgaMonochrysis lutheri grown under the accumulation regime of cultivation has been investigated for the first time. A predominance of triacylglycerols in the neutral lipids, of phosphatidylcholine in the phospholipids, and of digalactosyldiacylglycerols in the glycolipids has been established. New natural alkan-8-ones of the C₃₆-C₅₀ series have been detected.Institute of the Chemistry of Plant Substances. Academy of Sciences, of the Republic of Uzbekistan, Tashkent. FAX (3712) 62 73 48. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 325–330, May–June, 1994.     

Diketone cembrenolides from the pacific gorgonian lophogorgia alba

Three new diketone cembrenolides have been isolated from the Pacific sea whip Lophogorgia alba. The structure of lophodione (1) was assigned by X-ray crystallography, and isolophodione (2) and epoxylophodione (3) have been assigned based upon interconversion with (1) and by proton difference decoupling and nOe experiments. The previously reported neurotoxin, lophotoxin (4) was also isolated from L. alba. Since L. alba does not contain the endo-symbiotic algae (zooxanthellae), which are well-known in the Caribbean and Indo-Pacific corals, compounds 1–4 would appear to be of animal origin.     

Some aspects of element distribution inBetula alba, a contribution to representative sampling of terrestrial plants for multi-element analysis

Summary The leaves of six differently aged birch trees (Betula alba), growing under slightly varying soil conditions, were collected representatively. The elements Ca, K, Mg and Zn were determined by different analytical methods (AAS and AES/ICP). The data sets obtained were in good agreeent with each other. The biological variances of Al, Ba, Ca, Cu, Fe, K, Mg, P and Zn between leaves of different trees were less than 30%, with the exception of phosphorus (38%). Ca, K, Mg, Mn and Zn show an increase of between 50%–70% depending on the height of the trees. The developed sampling procedure (5–10 trees per ecosystem) can be adapted to produce a representative sampling design on population level.

---

Einige Aspekte der Elementverteilung inBetula alba, ein Beitrag zur repräsentativen Probenahme von terrestrischen Pflanzen für die Multielement-Analyse

     

Lipids and lipopolysaccharides of the genusFlavobacterium

The fatty acid compositions of the free lipids of three strains and the monosaccharide compositions of the lipopolysaccharides of four strains of new species of microorganisms of the genusFlavobacterium have been studied. The acidic nature of the polysaccharides of the LPSs of the microorganisms studied has been shown.Pacific Ocean Institute of Bioorganic Chemistry of the Far Eastern Scientific Center of the USSR Academy of Sciences, Vladivostok, and Institute of Microbiology of the USSR Academy of Sciences, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 564–567, September–October, 1986.     

Lipids of microalgae V. Composition of the lipids of the biomass ofMonochrysis lutheri grown with periodic illumination

It has been shown that in the biomass ofMonochrysis lutheri grown under the conditions of an accumulation culture with periodic illumination the level of total lipids, including the majority of classes of glycolipids and some phospholipids, is lower than on continuous illumination. In the fatty acids of the triacylglycerols the amounts of the 20:4 and 20:5 species were somewhat lower while the amounts of polar lipids had increased.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 601–604, September–October, 1994.     

Lipids of the fruit ofAcanthopanax sessiliflorus

In the lipids of the seeds and pericarp of the introduced speciesAcanthopanax sessiliflorus (Rupr. et Maxim.) Seem (familyAraliaceae), 23 classes of compounds have been detected, of which 19 have been identified. Sixteen of the classes have been studied. The lipids of the pericarp contain a more complex set of components than the seeds. Hydroxyacyldiacylglycerides, fatty acid methyl esters, and a complex group of pthalicacidesters have been detected in the familyAraliaceae for the first time. The fatty acid compositions of the seed and pericarp lipids are characterized by a high level of petroselinic acid.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 760–766, November–December, 1985.     

Biflavones from the leaves of Araucaria bidwillii Hooker and Agathis alba foxworthy (araucariaceae)

Six biflavones have been isolated from the leaf extracts of Araucaria bidwillii Hooker and Agathis alba Foxworthy; 7-O-methylcupressuflavone (2a) and 7,7″-di-O-methylagathisflavone (1c) are new compounds. The others are 7-O-methylagathisflavone (1a), 4?,7-di-O-methylagathisflavone (1b), 7,7″-di-O-methylcupressuflavone (2b) and bilobetin (3). In addition, the presence of several other biflavones has been indicated by TLC examination (Table 3).     

Comparing the stability of tribenzo[ b , n , pqr ]perylene and tribenzo[ b , k , pqr ]perylene

Two isomeric benzenoid hydrocarbons – tribenzo[b,n,pqr]perylene and tribenzo[b,k,pqr]perylene played a crucial role in the formulation of the Clar aromatic sextet theory. The basic assumption of this theory is that tribenzo[b,n,pqr]perylene is more stable than tribenzo[b,k,pqr]perylene because the former has five, whereas the latter only four aromatic sextets. We now approach this stability problem from a different direction. By means of a recently developed molecular-orbital-based method it is possible to estimate the energy effects of individual cycles, as well as pairs, triplets, etc. of cycles in polycyclic conjugated molecules. From these energy-effects one can better understand which structural details are responsible for the thermodynamic stability of the underlying molecule. In particular, it is possible to rationalize (in a quantitative manner) the causes of differences in the thermodynamic stability of isomers. Our analysis corroborates the conclusion of Clar theory, but points out a number of hitherto overlooked structure-stability connections.     

Diastereoselective total synthesis of (+)-morusimic acid B, an amino acid from Morus alba

An efficient, flexible and diastereoselective synthesis of the naturally occurring pyrrolidine amino acid, (+)-morusimic acid B, has been accomplished. Starting from chiral, optically active (+)-(3S)-hydroxy butyric acid methyl ester the key steps of our synthesis are diastereoselective α-alkylation of its dianion to introduce the main part of the side chain, Curtius rearrangement of the hydrazide derivative to a 2-oxazolidinone followed by N→π-cyclization with mercury(II) acetate to generate the cis-2,5-disubstituted pyrrolidine ring. The remote C-3 stereocentre is established after chain elongation with the dianion of methyl acetoacetate and asymmetric hydrogenation of the resulting β-oxoester with Noyori's Ru(II)-(R)-BINAP catalyst.