Antioxidative compounds from leaves of Tahongai (<Emphasis Type="Italic">Klienhovia hospita</Emphasis>)

In our effort to find antioxidant agent, we focused on Tahongai (Kleinhovia hospita) which have been used traditionally in Indonesia as medicinal herbal to cure liver disease. Based on the biologically guided fractionation using DPPH radical scavenging assay, eleutherol and kaempferol 3-O-β-d-glucoside was isolated from the leaves of K. hospita. Kaempferol 3-O-β-d-glucoside (1) and eleutherol (2) scavenged the radical with IC₅₀ of 71.4 and 491.8 μM, respectively. In addition, both of the compounds did not exhibit cytotoxicity on HepG2 cells.     

Antioxidant properties and structural analysis of phenolic glucosides from bark of <Emphasis Type="Italic">Populus ussuriensis</Emphasis> Kom.

The methanol (MeOH) extract of Populus ussuriensis Kom. bark was analyzed for antioxidant assessing by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging potential. Among fractions using several solvents, the ethyl acetate (EtOAc) soluble fraction, which showed strong antioxidant activity (IC₅₀ 2.02 ± 0.01 μg/ml), was further purified by Thin layer chromatography (TLC) guided Sephadex LH-20 column chromatography. Three known phenolic glucosides, picein (I), salicortin (II), grandidentatin (III), and that of a new, 2-hydroxycyclohexyl-4′-O-p-coumaroyl-β-d-glucopyranoside (isograndidentatin A), were isolated and their structures were elucidated on the basis of physiochemical and spectroscopic methods. This was the first report of the chemical composition of P. ussuriensis bark. Phenolic glucosides III and IV exhibited strong antioxidant activities, with IC₅₀ values 6.73 ± 0.01 and 6.69 ± 0.01 μM, respectively, comparable to the control (α-tocopherol, IC₅₀ 6.80 ± 0.01 μM). P. ussuriensis bark EtOAc-soluble fraction and compounds III and IV could be used as biopreservatives in food applications as well as for cosmetic and medicinal preparations, to alleviate oxidative stress.     

Heartwood extractives from the Amazonian trees <Emphasis Type="Italic">Dipteryx odorata,Hymenaea courbaril</Emphasis>, and <Emphasis Type="Italic">Astronium lecointei</Emphasis> and their antioxidant activities

Heartwood extracts from Amazonian trees cumaru-ferro (Dipteryx odorata), jatoba (Hymenaea courbaril), and guarita (Astronium lecointei) exhibit antioxidant activities comparable with that of α-tocopherol, a well-known antioxidant. This article reports the characterization of the antioxidant compounds in the extracts of the three heartwoods. Silica gel column chromatography of the cumaru-ferro EtOAc extract yielded (−)-(3R)-7,2′,3′-trihydroxy-4′-methoxyisoflavan and (+)-(3R)-8,2′,3′-trihydroxy-7,4′-dimethoxyisoflavan. Silica gel column chromatography followed by preparative high-performance liquid chromatography of the jatoba EtOAc extract yielded (−)-fisetinidol and (+)-trans-taxifolin. Chemical structures were assigned using electron-ionization mass spectrometry, ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopy including nuclear Overhauser effect spectroscopy (NOESY), as well as optical rotation and circular dichroism. Gas chromatography-mass spectrometry demonstrated that the isolated compounds were predominant in the EtOAc extracts. In the guarita EtOAc extract, catechin and gallic acid were identified by comparing their retention times and mass fragmentation patterns with those of authentic samples. Antioxidant activity determined by the 1,1-diphenyl-2-picrylhydrazyl assay demonstrated that all these compounds had activities comparable with that of α-tocopherol. Part of this report was presented at the 57th Annual Meeting of the Japan Wood Research Society, Hiroshima, August 2007     

Stereochemistry and biosynthesis of (+)-lyoniresinol,a syringyl tetrahydronaphthalene lignan in <Emphasis Type="Italic">Lyonia ovalifolia</Emphasis> var. <Emphasis Type="Italic">elliptica</Emphasis> II: feeding experiments with <Superscript>14</Superscript>C labeled precursors

To clarify the biosynthetic pathway for syringyl lignans, especially syringyl tetrahydronaphthalene lignans and formation of the C2–C7′ linkage, production of (+)-lyoniresinol (LYR) and its predicted intermediates [syringaresinol (SYR), 5,5′-dimethoxylariciresinol (DMLR), and 5,5′-dimethoxysecoisolariciresinol (DMSLR)] in Lyonia ovalifolia var. elliptica was investigated by means of feeding experiments with radiolabeled precursors. Following individual administration of l-[U-¹⁴C]phenylalanine (Phe), [8-¹⁴C]sinapyl alcohol (SA), and [8,8′-¹⁴C]SYR to excised young shoots of L. ovalifolia and their subsequent metabolism, free [¹⁴C]lignans and [¹⁴C]lignan glycosides were extracted with methanol from stems and leaves and were divided into ethyl acetate-soluble fractions (lignans) and aqueous fractions (lignan glycosides), respectively. Using a combination of xylanase, cellulase, and β-glucosidase, the glycosides were hydrolyzed to liberate [¹⁴C]lignans as aglycones. l-[U-¹⁴C]Phe was incorporated into (+)-[¹⁴C]SYR [stem 0.38%, 8% enantiomeric excess (e.e.)], (−)-[¹⁴C]SYR (leaves 2.75%, 72% e.e.), (+)-[¹⁴C]DMLR (stem 0.07%, 18% e.e. and leaves 0.009%, 58% e.e.), (−)-[¹⁴C]DMSLR (stem 0.03%, 46% e.e. and leaves 0.05%, 20% e.e.), (+)-[¹⁴C]LYR (leaves 0.013%, 22% e.e.) and glycosides of (+)-[¹⁴C]LYR (stem 0.036%, 50% e.e.) in 24h. Based on the percent incorporation and enantiomeric composition of the lignans, the biosynthetic pathway of (8R,8′R)-(+)-LYR was proposed as follows: a nonselective dehydrogenative dimerization of sinapyl alcohol yields (±)-SYR, which is reduced with low specificity to give (8R,8′R)-(+)-DMLR. This is cyclized to directly give (+)-LYR as well as reduced again to (8R,8′R)-(−)-DMSLR. Although further transformation of (−)-DMSLR also leads to the formation of (+)-LYR, cyclization could be a main pathway for (+)-LYR biosynthesis. This report was presented at the IAWPS 2005 International Symposium on Wood Science and Technology, Yokohama, November 2005     

Antioxidative activity and anti-inflammatory effects of diarylheptanoids isolated from <Emphasis Type="Italic">Alnus hirsuta</Emphasis>

Two diarylheptanoids, 1,7-bis-(3,4-dihydroxyphenyl)-heptane-3-one-5-O-β-d-xylopyranoside (I) and 1,7-bis-(3,4-dihydroxyphenyl)-heptane-5-O-β-d-xylopyranoside (II), were isolated from the bark of Alnus hirsuta. Compounds I and II exhibited strong antioxidative activity against 1,1-diphenyl-2-picrylhydrazyl radicals, with IC₅₀ values of 8.36 ± 0.54 and 8.67 ± 1.46 μM, respectively. In addition, we demonstrated that compounds I and II inhibited the production of nitric oxide and reactive oxygen species and the expression of proinflammatory molecules such as inducible nitric oxide synthase and cyclooxygenase-2 in lipopolysaccharide-induced macrophages. According to our results, the two diarylheptanoids isolated from the bark of A. hirsuta exhibited significant antioxidative activity and anti-inflammatory effects and may be useful in the pharmaceutical industry for alleviating oxidative stress.     

Two new chalcone glycosides from the stems of Entada phaseoloides

Two new chalcone glycosides 4′-O-(6″-O-galloyl-β-d-glucopyranosyl)-2′,4-dihydroxychalcone (1) and 4′-O-(6″-O-galloyl-β-d-glucopyranosyl)-2′-hydroxy-4-methoxychalcone (2) together with one known chalcone glycoside 4′-O-β-d-glucopyranosyl-2′-hydroxy-4-methoxychalcone (3) were isolated from the stems of Entada phaseoloides. The structures of the new compounds were elucidated on the basis of extensive spectroscopic analysis, including HSQC, HMBC, ¹H–¹H COSY, and chemical evidences. This is the first report of chalcone-type compounds isolated from the genus Entada.     

Effects of stilbenes from bark of <Emphasis Type="Italic">Picea glehnii</Emphasis> (Sieb. et Zucc) and their related compounds against feeding behaviour of <Emphasis Type="Italic">Reticulitermes speratus</Emphasis> (Kolbe)

The effects of stilbene glucosides and related compounds on termite feeding behavior were investigated using paper disc methods against the subterranean termite Reticulitermes speratus. The stilbene-rich fraction and isorhapontin (3-methoxy-3,4, 5-trihydroxystilbene-3--d-glucoside) from bark extracts of Picea glehnii showed avoidance by termites in choice tests. In the no-choice tests using compounds purified from the stilbene-rich fraction, the largest feeding deterrent effect was observed for piceid (3,4,5-trihydroxystilbene-3--d-glucoside), followed by isorhapontin, and astringin (3,3,4,5-tetrahydroxystilbene-3--d-glucoside), at the concentrations from 0.63 to 2.5µmol/disc. No change in activity was observed at retentions of more than 5.0µmol/disc. When the activities of isorhapontin and its aglycone derivative (isorhapontigenin: 3-methoxy-3,4,5-trihydroxystilbene) were compared with that of taxifolin (3,3,4,5,7-pentahydroxyflavanone) in the no-choice test, the stilbenes exhibited a larger antifeedant potential. Methylation of isorhapontigenin increased its termiticidal activity.Part of this study was presented at the 32nd Annual Meeting of the International Research Group on Wood Preservation, 2001     

Biochanin A triglycoside from Andira inermis

A new isoflavonol triglycoside, biochanin A 7-O-β- -apiofuranosyl-(1→5)-β- -apiofuranosyl-(1→6)-β- -glucopyranoside (1), was isolated from Andira inermis roots in addition to the known compounds genistein 7-O-β- -apiofuranosyl-(1→6)-β- -glucopyranoside and lanceolarin.     

A glucosylceramide with antimicrobial activity from the edible mushroom <Emphasis Type="Italic">Pleurotus citrinopileatus</Emphasis>

The golden oyster mushroom Pleurotus citrinopileatus is a popular edible mushroom with multifunctional biological activities, but there are a limited number of previous studies on its chemical composition. This is the first report of the isolation of glucosylceramide with antimicrobial activity from the fruiting body of this mushroom. This compound was identified as 1-O-β-d-glucopyranosyl-(2S,3R,4E,8E)-2-[(2R)-2-hydroxyhexadecanoylamino]-9-methyl-4,8-octadecadiene-1,3-diol. The IC₅₀ value of this compound for the growth of Escherichia coli and Staphylococcus aureus was 275.1 μM (200 μg/ml) and 323.2 μM (235 μg/ml), respectively.     

Two new furostanol saponins from Tribulus terrestris L.

Two new furostanol glycosides, named tribufurosides I (1) J (2), were isolated from the fruits of Tribulus terrestris L. by a combination of chemical and spectroscopic methods. Its structures were established as 26-O-β-d-glucopyranosyl-(25S)-5α-furost-12-one-2α,3β,22α,26-tetraol-3-O-β-d-glucopyranosyl (1 → 2)-β-d-glucopyranosyl (1 → 4)-β-d-galactopyranoside (1) and 26-O-β-d-glucopyranosyl-(25R)-5α-furost-20(22)-en-12-one-2α,3β,26-triol-3-O-β-d-glucopyranosyl (1 → 4)-β-d-galactopyranoside (2).     

Two new polyols and a new phenylpropanoid glycoside from the basidiomycete Lactarius deliciosus

Two new polyols, 3-hydroxymethyl-2-methylenepentane-1,4-diol (1) and 1-methylcyclohexane-1,2,4-triol (2), and a new phenylpropanoid glycoside, eugenyl 4″-O-acetyl-β-rutinoside (3), together with seven known steroids (5–11) were isolated from the fruiting bodies of the basidiomycete Lactarius deliciosus. The structures of these compounds were elucidated by the analysis of spectroscopic data.     

Synthesis of isoacteoside, a dihydroxyphenylethyl glycoside

The total chemical synthesis of isoacteoside (1), 2-(3,4-dihydroxyphenyl)ethyl 6-O-caffeoyl-3-O-(-l-rhamnopyranosyl)--d-glucopyranoside, is described. An acteoside acetate with benzyl groups at the catechols (3: 2-(3,4-dibenzyloxyphenyl)ethyl 2,6-di-O-acetyl-4-O-[3,4-bis(O-benzyl)caffeoyl]-3-O-(-l-rhamnopyranosyl)--d-glucopyranoside) was treated with a solution of methy-lamine in methanol (MeNH₂ in MeOH) to perform both deacetylation and caffeoyl migration, affording an isoacteoside derivative with benzyl groups at the catechols4b: 2-(3,4-dibenzyloxyphenyl)ethyl 6-O-[3,4-bis(O-benzyl) caffeoyl] -3-O-(-l-rhamnopyranosyl)--d-glucopyranoside —in 34% yield. Debenzylation of4b was successfully accomplished by catalytic transfer hydrogenation using 1,4-cyclohexadiene to give the target compound isoacteoside (1) in 54% yield.¹H and¹³C nuclear magnetic resonance spectral data of the synthesized isoacteoside (1) were identical with those of the natural isoacteoside isolated fromPaulownia tomentosa (Thumb.) Steud.Part of this research was presented at the 51st Annual Meeting of the Japan Wood Research Society, Tokyo, April 2001     

Cycloartane saponins from Astragalus peregrinus as modulators of lymphocyte proliferation

From Astragalus peregrinus, four cycloartane-type saponins have been isolated and their structures elucidated by spectral means as 20(R),24(S)-epoxy-9β,19-cyclolanostane-3β,6α,16β,25-tetrol 3-O-β- -glucopyranoside (1), 20(R),24(S)-epoxy-9β,19-cyclolanostane-3β,6α,16β,25-tetrol 3-O-α- -rhamnopyranosyl-(1→4)-β- -glucopyranoside (2), 20(R),24(S)-epoxy-9β,19-cyclolanostane-3β,6α,16β,25-tetrol 3-O-α- -rhamnopyranosyl-(1→2)-β- -glucopyranoside (3) and 20(R),25-epoxy-9β,19-cyclolanostane-3β,6α,16β,24(S)-tetrol (24-O-acetyl)- 3-O-α- -rhamnopyranosyl-(1→2)-(6′-O-acetyl)-β- -glucopyranoside (4). Compounds 2 and 3 showed to stimulate the proliferation of mouse splenocytes and were not significantly cytotoxic.     

Electroantennogram responses of Dendrolimus superans (Lepidoptera: Lasiocampidae) to six volatiles of Larix gmelinii

Dendrolimus superans is one of the important pests feeding on the needles of Larix gmelinii. Six standard compounds, (1R)-(−)-α-pinene, (1S)-(−)-α-pinene, ocimene, (1S)-(−)-β-pinene, R(−)-α-phellandrene and camphene, the main volatiles of L. gmelinii were used to test the electroantennogram (EAG) responses of moths. The results show that the order of the EAG responses of moths to seven concentrations of these six compounds were as follows: mated females > virgin females > unmated males, except for 0.1 μL/μL R(−)-α-phellandrene, where the order was: virgin females > mated females > unmated males. There are statistically significant differences between the EAG responses of virgin females and unmated males (p < 0.05), and also between mated females with virgin females and mated females and unmated males (p < 0.01), which suggests that the mated females are more sensitive to the volatiles of host plant. The results of EAG responses of the mated females, virgin females and unmated males indicate that they are more sensitive to R(−)-α-phellandrene than to the other volatile components. The active time for the EAG responses of both mated females and unmated males occurs during the night, i.e., from 20:00 to 04:00 hours. This is consistent with their eclosion, mating and oviposition periods. __________ Translated from Scientia Silvae Sinicae, 2007, 43(7): 55–60 [译自:林业科学]     

Preparation of novel reagents 4-alkoxytrityl chlorides and their reaction with methyl Α-d-glucoside

A series of novel 4-O-alkoxytrityl chlorides (1) with different chain lengths was synthesized as a novel reagent for obtaining 6-O-alkylated cellulose with high regioselectivity via trityl groups in one reaction step without the use of any protective groups. These chlorides were reacted with methyl -d-glucoside, which was used as a model compound, to examine the reactivities toward the primary hydroxyl groups of cellulose to afford a series of 6-O-alkylated methyl -d-glucosides in high yields. The product compounds were found to have interesting solubilities and thermal properties. Thus, newly prepared trityl chloride derivatives were found to be useful regioselective derivatization reagents on the primary hydroxyl group in carbohydrates, especially in cellulose.     

Stereochemistry and biosynthesis of (+)-lyoniresinol, a syringyl tetrahydronaphthalene lignan in Lyonia ovalifolia var. elliptica I: isolation and stereochemistry of syringyl lignans and predicted precursors to (+)-lyoniresinol from wood

Steps leading to the biosynthesis of syringyl lignans and tetrahydronaphthalene and naphthalene lignans, especially the formation of the C2–C7′ linkage, have not been elucidated. Lyoniresinol is a typical syringyl lignan, as well as a tetrahydronaphthalene lignan found in Lyonia ovalifolia var. elliptica. To demonstrate the biosynthetic pathway for (+)-lyoniresinol, three putative biosynthetic intermediates of lyoniresinol, syringaresinol, 5,5′-dimethoxylariciresinol, and 5,5′-dimethoxysecoisolariciresinol, were isolated from wood. The identity of the putative intermediates was confirmed by spectroscopic analyses, as well as by comparison of spectral and chromatographic data with those of authentic samples previously synthesized. The stereochemistry (enantiomeric composition and absolute configuration) of the isolated lignans were determined as (±)-syringaresinol, (8S,8′S)-(−)-5,5′-dimethoxylariciresinol [46% enantiomeric excess (e.e.)], (8S,8′S)-(+)-5,5′-dimethoxysecoisolariciresinol (91% e.e.), and (8R,8′R)-(+)-lyoniresinol (42% e.e.). The absolute configurations of (+)-and (-)-5,5′-dimethoxylariciresinols, and (+)-and (-)-5,5′-dimethoxysecoisolariciresinols were determined by their synthesis (catalytic reduction) from (8R,8′R)-(+)-and (8S,8′S)-(-)-syringaresinols and by subsequent chiral high-performance liquid chromatography analysis. This report was presented at the 55th Annual Meeting of the Japan Wood Research Society, Kyoto, March 2005     

Absolute configuration of arylglycerol-β-aryl ethers obtained by asymmetric reduction of the correspondingα-ketonic compound with intactFusarium solani cells

When (±)--oxo-guaiacylglycerol--(vanillic acid) ether (1) is degraded byFusarium solani M-13-1, the-ketone is initially reduced to giveerythro andthreo guaiacylglycerol--(vanillic acid) ethers (2), arylglycerol--aryl ethers, both of which are enantiomerically pure. The absolute configuration in each2 was determined by Mosher's method; the products were converted to,-di-(R)--methoxy--trifluoromethylphenylacetates (MTPA esters) (3) oferythro (-)- andthreo (+)-veratrylglycerol--(methyl vanillate) ethers (3), whose¹H nuclear magnetic resonance (NMR) spectra were examined and compared with those of four di-(R)-MTPA ester (3) diastereomers from chemically synthesizederythro (±)-3 andthreo (±)-3. To assign the- and-MTPA-OCH₃ peaks, the¹H NMR scans of several compounds that have substructures of 3 and their 3,4,5-trimethoxyphenyl analogues were examined. When a racemic alcohol reacts with (R)-MTPA to give a pair of (R)-MTPA ester diastereomers, the value was defined as the absolute value of the difference in the¹H chemical shifts of the peak between the diastereomers. It was found that the values of-MTPA-OCH₃ were larger than those of-MTPA-OCH₃ owing to a shielding effect of the veratryl ring located on the-MTPA-OCH₃, and that the-MTPA-OCH₃ peaks in the 3,4,5-trimethoxyphenyl compounds shifted downfield relative to those in the veratryl compounds. On the basis of the¹h NMR data of (R)-MTPA esters, the absolute configuration of the four chemically prepared diastereomers (3) were determined. The catabolicerythro 3 [fromerythro (-)-3] andthreo 3 [fromthreo (+)-3] were identical to (R, S, R)-erythro 3 and (R, S, S)- threo 3, respectively. An hydrogen species in the fungal reduction would attack the-ketone fromre-face of both (R)-1 and (S)-1, givingerythro (S, R)-2 andthreo (S, S)-2, respectively.Part of this paper was presented at the 33rd Lignin Symposium, Tsukuba, November 1988     

Investigation on hydrogen abstraction from methyl glucoside by active oxygen species under oxygen delignification conditions III: effects of the origin of active oxygen species

Carbohydrate model compounds methyl β-d-glucopyranoside (MGPβ), methyl α-d-glucopyranoside (MGPα), and methyl β-d-mannopyranoside (MMPβ) and the deuterium compounds of MGPβ labeled at the anomeric or C-2 positions (MGPβ-1D, MGPβ-2D) were reacted with active oxygen species (AOS) generated in situ by reactions between O₂ and a co-treated phenolic lignin model compound, 4-hydroxy-3-methoxybenzyl alcohol (VAlc), under conditions simulating oxygen delignification (0.5 mol/l NaOH, 0.36 mmol/l Fe³⁺, 1.1 MPa O₂, 95°C). MGPβ was degraded more than MGPα but less than MMPβ when the pairs MGPβ/MGPα and MGPβ/MMPβ, respectively, were treated, which indicates that the configurational differences at the anomeric and C-2 positions influence the reactivity of AOS toward these compounds. When the pairs MGPβ/MGPβ-1D and MGPβ/MGPβ-2D were treated, no clear kinetic isotope effects were observed in either case. These results contrasted with those obtained when another phenolic compound, 2,4,6-trimethylphenol (TMPh), was used as the AOS generator instead of VAlc under exactly the same conditions. Clear kinetic isotope effects were observed when using TMPh. Because it is not easily accepted that the anomeric and C-2 hydrogen abstractions are minor reaction modes only for AOS generated in the VAlc system, it is suspected that the AOS do not show any clear kinetic isotope effect even though the AOS abstract an objective hydrogen.     

neo-Clerodane diterpenes from Ajuga ciliata Bunge and their neuroprotective activities

Three new (1–3) and three known (4–6) neo-clerodane diterpenes have been isolated from the whole plants of Ajuga ciliata Bunge. The structures of the new compounds were elucidated as (12S)-1β,6α,19-triacetoxy-18-chloro-4α,12-dihydroxy-neo-clerod-13-en-15,16-olide (1), (12S,2′S)-12,19-diacetoxy-18-chloro-4α,6α-dihydroxy-1β-(2-methylbutanoyloxy)-neo-clerod-13-en-15,16-olide (2), and (12S)-6α,18,19-triacetoxy-4α,12-dihydroxy-1β-tigloyloxy-neo-clerod-13-en-15,16-olide (3), on the basis of spectroscopic data analysis. All the diterpenes were evaluated for the neuroprotective effects against MPP⁺-induced neuronal cell death in dopaminergic neuroblastoma SH-SY5Y cells and compounds 2–5 exhibited moderate neuroprotective effects.     

Neuropharmacological activities of phytoncide released from <Emphasis Type="Italic">Cryptomeria japonica</Emphasis>

Forest-air bathing and walking (shinrin-yoku) is beneficial to human heath. In this study the phytoncide (volatile compounds) released from Cryptomeria japonica plantation forest was characterized by using solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS). The main volatile compounds were α-pinene (19.35%), β-myrcene (16.98%), d-limonene (15.21%), and γ-muurolene (7.42%). Furthermore, the neuropharmacological activity of the essential oils from leaves of C. japonica (ECJ) was evaluated by several animal behavior tests. ECJ could prolong the sleeping phase of ICR (imprinting control region) mice in the pentobarbital-induced sleeping time model. Furthermore, both EJC and one of its monoterpenes, d-limonene, possessed potent anxiolytic and analgesic activities based on the results obtained from elevated plus maze and writhing tests. The volatile compounds released from C. japonica provide relaxing and stress-relieving effects on mice, and further study on the effect of phytoncide on humans is worthwhile.