Lennart N. Lundgren

Effects of light and nutrient stress on leaf phenolic chemistry in salix dasyclados and susceptibility to Galerucella lineola (Coleoptera)

The amounts of phenolic compounds present in Salix dasyclados Wimm. leaves, and the susceptibility of the tissue to the leaf beetle Galerucella lineola F., were determined in laboratory grown plants stressed with respect to light and nutrient availability. Plants of clonal origin were grown in units with circulating nutrient solutions under (1) low light with free access to nutrients (low carbon supply), (2) high light with free access to nutrients (optimal conditions), and (3) high light with suboptimal nutrient supply (low nutrient supply). Concentrations of phenolic compounds in plants with low carbon supply were only about one-third compared with the other two treatments. The relative availability of carbohydrates for construction of carbon-based defensive compounds, such as phenolics, may explain the different susceptibility of willow leaves when grown under the specified environments. Beetles consumed about five times as much leaf tissue on plants low in carbon and rich in nitrogen as in the other two treatments.

An oligomer from flaxseed composed of secoisolariciresinoldiglucoside and 3-hydroxy-3-methyl glutaric acid residues.

A straight-chain oligomeric structure composed of five secoisolariciresinoldiglucoside (SDG) residues interconnected by four 3-hydroxy-3-methyl glutaric acid (HMGA) residues (molecular weight ca. 4000 Da) was assigned to the main lignan of flaxseed on the basis of nuclear magnetic resonance spectroscopy (NMR).

Polymeric fractions containing phenol glucosides in flaxseed

Abstract Extract rich in phenolic compounds was obtained from flaxseed with 1,4-dioxane:ethanol (1:1, v/v). This extract (whole polymer) was fractionated by solid-phase extraction into three “polymeric” fractions of comparable polarity. HPLC analyses of the base hydrolysates of the three polymeric fractions showed that they contain the same UV-absorbing components, though at different levels and all contained substantial amounts of a lignan, secoisolariciresinoldiglucoside (SDG). Fractionation of the base hydrolysates by column chromatography, followed by high performance liquid chromatography (HPLC) yielded two pure hydroxycinnamic acid derivatives; 4-O-β- d -glucopyranosyl-p-coumaric acid and 4-O-β- d -glucopyranosylferulic acid, whose structures were identified by nuclear magnetic resonance spectroscopy (NMR). NMR analysis showed all three polymeric fractions to have phenolic and aliphatic components and, in line with HPLC, suggested some structural variations between these fractions. The results of this study suggest that the glucosylated phenolic compounds of flaxseed exist in polymeric structure(s) containing ester linkages.

Arylbutanoid and diarylheptanoid glycosides from inner bark of Betula pendula

From the inner bark of Betula pendula, four new disaccharide glycosides, two of (−)-rhododendrol and two of platyphyllone, were isolated along with a new trisaccharide glycoside of (−)-centrolobol and several known compounds. The structures were elucidated by high field 1H and 13C NMR spectroscopy. Assignments of 1H and 13C NMR spectra were made by H,H- and C,H-COSY.

Phenolics from inner bark of Pinus sylvestris

Abstract 2-O-[4′-(α- Hydroxypropyl )-2′- methoxyphenyl ]-1-O-β- d - xylopyranosyl glycerol and 3′-O-methylcatechin, in addition to 24 known phenolic compounds, have been isolated from inner bark of Pinus sylvestris and identified on the basis of chemical and spectroscopic evidence.

Triterpenoid saponins from Quillaja saponaria

Three new saponins were isolated from a commercial bark extract of Quillaja saponaria Molina. These compounds were also obtained as degradation products from larger saponins in this extract when treated with strong alkali. The compounds were characterized, using mainly NMR spectroscopy, mass spectrometry and chemical methods, as quillaic acid 3-O-¿beta-D-galactopyranosyl-(1-->2)-beta-D-glucopyranosiduronic acid¿, 3-O-¿alpha-L-rhamnopyranosyl-(1-->3)-[beta-D-galactopyranosyl-(1-->2)] -beta-D-glucopyranosiduronic acid¿ and 3-O-¿beta-D-xylopyranosyl-(1-->3)-[beta-D-galactopyranosyl -(1-->2)]-beta-D-glucopyranosiduronic acid¿, respectively.

Monoaryl and cyclohexenone glycosides from needles of Pinus sylvestris

Abstract The 4′- O -β- d -glucopyranosides of 4-(4′-hydroxyphenyl)-2-butanone [rheosmin] and its 3′-methoxy derivative [zingerone]; the 3- O -β- d -glucopyranosides of 3-hydroxy-1-(4′-hydroxy-3′-methoxyphenyl)-1-propanone [β-hydroxypropiovanillone] and trans -3-hydroxy-1-(4′-hydroxy-3′-methoxyphenyl propene [ trans -coniferyl alcohol]; and the 3′- O -β- d -glucopyranosides of (4 S ,3′ R )-4-hydroxy-4-(3′-hydroxybutyl)-3,5,5-trimethyl-2-cyclohexenone [dihydrovomifoliol] and (4 S ,3′ R )-4-hydroxy-4-(3′-hydroxy- trans -1′-butenyl-3,5,5-trimethyl-2-cyclohexenone [vomifoliol] have been isolated from the needles of Pinus sylvestris and identified.

Lignan glycosides from inner bark of Betula pendula

Abstract Four lignan glycosides [lyoniside, nudiposide, (−)-isolariciresinol 3α-O-β- d -xylopyranoside and (2R,3R)-2,3- dihydro-3-hydroxymethyl-7-methoxy-2-(3′-methoxy-4′-α- l -rhamnopyranosyloxyphenyl)-5-benzofuranpropanol ] were isolated from the inner bark of Betula pendula, in addition to (+)-catechin, (+)-catechin 7-O-β- d -xylopyranoside , salidroside, tachioside and isotachioside.

Cis- and trans-dihydroquercetin glucosides from needles of Pinus sylvestris

Abstract (−)- cis -2,3-Dihydroquercetin (presumably as the 3′- O -β- d -glucopyranoside); the 3′- O - d -glucopyranosides of (+)- trans -2,3-dihydroquercetin, dihydromyricetin and eriodictyol; (+)-catechin and (+)-gallocatechin have been isolated from the needles of Pinus sylvestris . The dihydroquercetin aglycones interconvert in methanolic solution. Two chemotypes of Pinus sylvestris can be distinguished on the basis of their dihydroquercetin, dihydromyricetin and eriodictyol contents.

Dilignol glycosides from needles of Picea abies

Abstract (2R,3R)-2 3-Dihydro-2-(4′-hydroxy-3′-methoxyphenyl)-3-(hydroxymethyl)-7-methoxy-5-benzofuranpropanol 4′-O-β- d -glucopyranoside [dihydrodehydrodiconiferyl alcohol glucoside], (2R,3R)-2 3-dihydro-7-hydroxy-2-(4′-hydroxy-3′-methoxyphenyl)-3-(hydroxymethyl)-5-benzofuranpropanol 4′-O-β- d -glucopyranoside and 4′-O-α- l -rhamnopyranoside, 1-(4′-hydroxy-3′-methoxyphenyl)-2- [2″-hydroxy-4″-(3-hydroxypropyl)phenoxy]-1, 3-propanediol 1-O-β- d -glucopyranoside and 4′-O-β- d -xylopyranoside, 2,3-bis[(4′-hydroxy-3′-methoxyphenyl)-methyl]-1,4-butanediol 1-O-β- d -glucopyranoside [(−)-seco-isolariciresinol glucoside] and (1R,2S,3S)-1,2,3,4-tetrahydro-7-hydroxy-1-(4′-hydroxy-3′-methoxyphenyl)-6-methoxy-2 3-naphthalenedimethanol α2-O-β- d -xylopyranoside [(−)-isolariciresinol xyloside] have been isolated from needles of Picea abies and identified.