Gert Eckhardt

Fucole, polyhydroxyoligophenyle aus Fucus vesiculosus

Abstract From the fraction of acetylated phenols of Fucus vesiculosus were isolated: phloroglucinol triacetate, difucol hexaacetate (2,2′,4,4′,6,6′-hexaacetoxydiphenyl), trifucol nonaacetate [1,5-di (2,4,6-triacetoxyphenyl)-2,4,6-triacetoxybenzene] and a mixture of two isomeric tetrafucol dodecaacetates A and B.

Alkaloids from rhamnaceae—XXVI : Nummularine -D, -E and -F, new cyclopeptide alkaloids from Zizyphus nummularia

Abstract From the benzene extract of the root bark of Zizyphus nummularia three new peptide alkaloids have been isolated: nummularine-D 1, -E 3 and -F 5. All three contain the 14-membered ring system. Nummularine-D is N-desmethyl-integerrenine. Nummularine-E has N,N-dimethylthreonine and nummularine-F has N,N-dimethylglycine as terminal amino-acid, neither of which has been found in such alkaloids before.

Polyhydroxyphenyläther aus der phaeophycee Sargassum muticum

Abstract From an acetylated fraction of Sargassum muticum (Yendo) Fensholt were isolated: phloroglucinol tri-acetate; diphlorethol pentaacetate (2,4,6,3′,5′-pentaacetoxydiphenyl ether), bifuhalol hexaacetate (2,4,6,3′,4′,5′-hexaacetoxydiphenyl ether), trifuhalol A octaacetate (2,6-diacetoxy-1-(3,4,5-triacetoxyphenoxy)-4-(2,4,6-triacetoxy- phenoxy)-benzene), and the new trifuhalol B octaacetate(3,5-diacetoxy -1-(2,4,6-triacetoxyphenoxy)-2-(3,4,5- triacetoxyphenoxy)-benzene).

Jubanin-A und jubanin-B, neue cyclopeptidalkaloide aus Ziziphus jujuba

Abstract The known alkaloids mauritine-A, mucronine-D, amphibine-H, nummularine-A and -B and the previously undescribed jubanine-A and -B have been isolated from the stem bark of Ziziphus jujuba . The structures of the new compounds were elucidated by spectroscopic methods and by chemical degradation reactions.

Sativanine-a and sativanine-b, two new cyclopeptide alkaloids from the bark of Zizyphus sativa

Abstract From the bark of Zizyphus sativa , in addition to already described cyclopeptide alkaloids, two new compounds of this class, sativanine-A(1) and sativanine-B(2), were isolated. Both alkaloids contain 14-membered ring systems. 1 belongs to the integerrine type, while 2 is similar to nummularine-G, with an additional ring in the side chain.

Chlorierte phlorethole aus Laminaria ochroleuca

Abstract After acetylation of the phenolic fraction, monochlorodiphlorethol acetate was detected by MS and a monochlorotriphlorethol C heptaacetate was identified in this alga. Halogenation of triphlorethol C acetate did not yield the natural compound, but instead an isomeric monochloro- and a symmetrical dichloroderivative. The high MW phlorotannins are also halogenated.

Polyhydroxyphenyläther aus Laminaria ochroleuca

Abstract After acetylation of the phenolic fraction, the following compounds were isolated from Laminaria ochroleuca: phloroglucinol triacetate, diphlorethol pentaacetate (2,4,6,3′,5′-pentaacetoxydiphenyl ether) and triphlorethol C heptaacetate (1-acetoxy-3,5-bis(2,4,6-triacetoxyphenoxy)benzene).

Carotenoid changes in the peel of the «Golden delicious» apple during ripening and storage

Summary Carotenoid pattern changes in the peel of Golden Delicious apple were followed for an entire maturation period and during storage at different temperatures (4° and 18°C). β-Carotene and lutein predominated in the initial chloroplast — carotenoid pattern which also revealed additional complexity. In the midseason the total carotenoid level reached a minimum after which a de novo synthesis yielded a 40-fold increase of violaxanthin and a 3.5-fold increase of neoxanthin. During storage the ripening process continued at a different rate, yielding the same final pattern of 15 carotenoids. Violaxanthin rose to a level of 55% and neoxanthin to 14%. A new apocarotenol, considered as a metabolite of violaxanthin, was detected only in the ripe fruit. On the basis of its properties and MS the structure 5,6-epoxy-5,6-dihydro-10′-apo-β-carotene-3,10′-diol is assigned. It may therefore be used as a parameter of the climacteric state. A modified pathway for violaxanthin biosynthesis is proposed.

Hysodricanin-A, Mauritin-H, Scutianin-F und Aralionin-C, vier weitere cyclopeptidalkaloide aus Ziziphus, Scutia und Araliorhamnus☆

Abstract From the bark extracts of Ziziphus hysodrica, Z. mauritiana, Scutia buxifolia and Araliorhamnus vaginata, in addition to known peptide alka

Cyclopeptide alkaloids of Zizyphus oenoplia

Abstract The known alkaloids zizyphine-A ( 1 ) and -B ( 2 ), abyssinine-A ( 4 ) and -B ( 5 ), and the previously undescribed zizyphine-C ( 3 ), -D ( 6 ) and -E ( 7 ) have been isolated from the stem bark of Zizyphus oenoplia . The structures of the new compounds were elucidated by spectroscopic methods applied to the alkaloids and to some of their transformation products, and by chemical degradation reactions.