A new ellagic acid glycoside from Paeonia delavayi

A new ellagic acid glycoside, 4'-O-methylellagic acid 4-O-beta-D-glucopyranoside (1), was isolated from the root cortex of Paeonia delavayi. The structure was elucidated on the basis of spectroscopic methods.     

Biosynthesis of a syringyl 8-O-4′ neolignan in Eucommia ulmoides: formation of syringylglycerol-8-O-4′-(sinapyl alcohol) ether from sinapyl alcohol

To investigate the biosynthesis and stereochemistry of syringylglycerol-8-O-4′-(sinapyl alcohol) ether (SGSE), a syringyl 8-O-4′ neolignan, feeding experiments and enzyme assays using Eucommia ulmoides were carried out. Diastereoselective formation of erythro-SGSE was found. When [8-¹⁴C]sinapyl alcohol was administered to excised shoots of E. ulmoides, ¹⁴C was incorporated into free SGSE and SGSE glucosides. In stems, incorporation into (+)-erythro-[¹⁴C]SGSE (0.037%) with 9.1% enantiomeric excess (% e.e.) was found; incorporation into the threo isomer was not detectable. Erythro-[¹⁴C]SGSE glucosides (0.047%) dominated over threo forms (0.007%) with 74.0% diastereomeric excess (% d.e.); both diastereomers were levorotatory with 32.0% e.e. and 18.3% e.e., respectively. In leaves, higher incorporation into (−)-erythro-[¹⁴C]SGSE (0.500%, 15.9% e.e.) than into the threo isomer (0.206%, 7.4% e.e.) was observed (41.6% d.e.). (−)-Erythro-[¹⁴C]SGSE glucosides (1.692%, 25.0% e.e.) were produced at higher rates than threo isomers (0.177%, 16.4% e.e.) with 81.0% d.e. In incubations of a mixture of [8-¹⁴C]sinapyl and [8-¹⁴C]coniferyl alcohols with an insoluble enzyme preparation from stems of E. ulmoides, erythro-SGSE was preferentially produced. The highest % d.e. (82.8) was observed at 60 min with the (+)-erythro isomer (21.4% e.e.) and the (−)-threo form (4.3% e.e.).Part of this report was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002, and the 47th Lignin Symposium, Fukuoka, October 2002     

In vivo hypoglycemic effects of phenolics from the root bark of Morus alba

Moracin M (1), Steppogenin-4′-O-β-D-glucosiade (2), Mullberroside A (3) were isolated from the root bark of Morus alba L. and identified by spectral evidence. Compounds 1, 2 and 3 were studied in hypoglycemic effects on alloxan-diabetic mice. The results showed that compounds 1, 2 and 3 all produced hypoglycemic effects. The compound 2 in a dose of 50 mg/kg exerted significant effect (p < 0.05), 2 and 3 in a dose of 100 mg/kg exerted obviously effect (p < 0.01). Meantime, the compound 1 in a dose of 100 mg/kg can make the fasting blood glucose level have decreasing tendency.     

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.     

A new dineolignan from Saururus chinensis root

A new tetrahydrofuradineolignan, called 4-O-demethylmanassantin A (1) was isolated from underground parts of Saururus chinensis together with three known dineolignans, 4-O-demethylmanassantin B (2), manassantin A (3) and manassantin B (4).     

A new chromone glycoside from Polygonum capitatum

A new chromone glycoside (1), 7-O-(6'-galloyl)-beta-D-glucopyranosyl-5-hydroxychromone was isolated from Polygonum capitatum.     

A new coumarin glycoside from the husks of Xanthoceras sorbifolia

From the husks of Xanthoceras sorbifolia, a new coumarin glycoside, isofraxetin-6-O-beta-D-glucopyranoside (1), was isolated. The structure was established on the basis of spectroscopic methods.     

A new flavone glycoside from the seeds of Shorea robusta

A new flavonoid, 3,7-dihydroxy-8-methoxyflavone 7-O-α- -rhamnopyranosyl-(1→4)-α- -rhamnopyranosyl-(1→6)-β- -glucopyranoside (1), was isolated from the seeds of Shorea robusta.     

New monoterpene glycosides from Paeonia lactiflora

Three new monoterpene glycosides named 4-O-methyl-paeoniflorin (1), isopaeoniflorin (2), and isobenzoylpaeoniflorin (3), together with two known monoterpene glycosides, paeoniflorin (4) and benzoylpaeoniflorin (5), were isolated from the roots of Paeonia lactiflora. Their structures were established on the basis of spectral and chemical evidence.     

A new flavone glycoside from the fruits of Luffa cylindrica

The methyl ester of diosmetin 7-O-beta-D-glucuronide (1) was isolated from the fruits of Luffa cylindrica. Its structure was determined by spectroscopic methods.     

Saponins from Furcraea selloa var. marginata

Four steroidal saponins were isolated from the leaves of Furcraea selloa var. marginata. These included one furostanol saponin, furcreafurostatin (1), and three known spirostanol saponins, furcreastatin (3), yuccaloeside C (4) and cantalasaponin-1 (5). The 22-O-methyl ether (2) of furcreafurostatin (1) was also characterized. The structures were determined by using a combination of spectroscopic techniques.     

Monoterpene glycosides from Paeonia delavayi

A new monoterpene glycoside, 4-O-methyl-4'-hydroxy-3'-methoxy-paeoniflorin (1), was isolated from the root cortex of Paeonia delavayi along with the known paeoniflorin, oxypaeoniflorin, benzoylpaeoniflorin, benzoyloxypaeoniflorin, albiflorin and a paeonilactone-A.     

A new phenolic glycoside from the aerial parts of Dryopteris fragrans

A new phenolic glycoside, 3,5-dimethyl-6-hydroxy-2-methoxy-4-O-D-glucopyranosyl-oxy-acetophenone (1), was isolated from the aerial parts of Dryopteris fragrans. The structure was elucidated on the basis of spectroscopic methods.     

Inhibition of glucose intestinal absorption by kaempferol 3-O-α-rhamnoside purified from Bauhinia megalandra leaves

Glucose intestinal absorption (GIA) is one of the factors that increase glycemia. Its reduction could be an important factor in decreasing hyperglycemia in diabetic patients. It has been shown that the aqueous extract of Bauhinia megalandra leaves inhibits GIA. In the present study we identified a compound present in the extract of B. megalandra responsible for the biological effect. The methanol extract of B. megalandra leaves was fractionated using different solvents, and high-speed counter-current chromatography yielding two pure compounds identified by ¹H NMR and ¹³C NMR as kaempferol 3-O-α-rhamnoside and quercetin 3-O-α-rhamnoside. The first one increased the K_M without changes in the V_MAX of GIA. In addition it exerted an additive inhibitory effect, on GIA, when combined with phlorizin. We suggest that kaempferol 3-O-α-rhamnoside is a competitive inhibitor of intestinal SGLT1 cotransporter.     

Chemical changes in terpenes of sugi (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>) wood during steam drying in kiln at high temperature

Sawdusts of sugi (Cryptomeria japonica) wood prepared before and after steam drying at 120°C in a kiln were extracted with n-hexane and ethyl acetate to give n-hexane extracts and ethyl acetate extracts. From gas chromatography-mass spectrometry analysis of the ethyl acetate extracts from woods before and after steam drying, the components of 4-epi-cubebol, cubebol, and 2,7(14),10-bis-abolatrien-1-ol-4-one, which existed in the raw sugi wood, were proved to disappear in the steam-dried wood. These components were also absent in the ethyl acetate extract of the steam-condensed solution of waste steam from the kiln outlet. When these three components were treated with 0.2% (v/v) acetic acid solution at 120°C, δ-cadinene was produced as a major product from both 4-epi-cubebol and cubebol by dehydration and cleavage of the cyclopropane ring, and cryptomerone from 2,7(14),10-bisabolatrien-1-ol-4-one by hydration. The chemical changes of the three components presumably occur during steam drying of the sugi wood. This study was presented in part at the 85th Spring Meeting of the Chemical Society of Japan, Kanagawa, Japan, March 26–29, 2005     

Antiplatelet activity of Varthemia iphionoides

Aqueous and alcoholic extracts, volatile oil and four flavonoids, xanthomicrol (1), kumatokenin (2), jaceidin (3) and 3, 3'-di-O-methylquercetin (4), isolated from Varthemia iphionoides were investigated for their in vitro anti-platelet activity. Aqueous extract and compounds (1), (2) and (4) showed anti-platelet activity. Volatile oil and the alcoholic extract did not exhibit any anti-platelet activity. Structures of the isolated compounds (1)-(4) were determined by spectroscopic methods (UV, IR, MS, (1)H-NMR).     

A new diglycosyl megastigmane from Carallia brachiata

A new megastigmane diglycoside was isolated from the leaves of Carallia brachiata. The structure was determined by spectroscopic methods as 3-hydroxy-5,6-epoxy-beta-ionol -3-O-beta-apiofuranosyl-(1-->6)-beta-glucopyranoside (1). Additionally, 29 known compounds consisting of two megastigmanes, one 1,2-dithiolane derivative, seven aromatic compounds, five condensed tannins, 12 flavonoids, and two glyceroglycolipids were isolated and identified.     

Antinociceptive activity of Maytenus rigida stem bark

Ethanol extract of Maytenus rigida stem bark and its fractions were assessed for antinociceptive activity in tail-flick test in rats. The activity was located in the chloroform, ethyl acetate and aq.methanol fractions. Phytochemical screening revealed that catechin was the only common class of compounds present on the ethanol extract as well as on the active fractions. 4'-Methylepigallocatechin, isolated from the ethyl acetate and aq.methanol fractions, showed antinociceptive effect in the tail-flick test (75 mg/kg; p.o.), which was reversed by the opiate antagonist naloxone (3 mg/kg; i.p.).     

Flavonoid glycosides from Microtea debilis and their cytotoxic and anti-inflammatory effects

Two new 5-O-glucosylflavones, 5-O-β-d-glucopyranosyl cirsimaritin (1) and 5, 4′-O-β-d-diglucopyranosyl cirsimaritin (2), four known flavonoids, cirsimarin (3), cirsimaritin (4), salvigenin (5), 4′, 5-dihydroxy-7-methoxyflavone (6), and a norisoprenoid, vomifoliol (7), have been isolated from the aerial parts of Microtea debilis. All isolates were tested for cytotoxicity in human cancer cell lines (Hep G2, COLO 205, and HL-60) and anti-inflammatory activities in LPS-treated RAW264.7 macrophages. Compound 6 was found to be a potent inhibitor to nitrite production in macrophages. Compounds 2, 4, 6, and 7 showed moderate anti-proliferative activity against COLO-205 cells with IC₅₀ values of 7.1, 13.1, 6.1, and 6.8 μM, respectively.     

The monomer composition controls the Σ<Emphasis Type="Italic">β-O</Emphasis>-4/Σ<Emphasis Type="Italic">O</Emphasis>-4 end monomer ratio of the linear lignin fraction

Lignins are cell wall phenolic heteropolymers that result from the oxidative coupling of three monolignols bearing p-coumaryl (H), coniferyl (G), and sinapyl (S) units, in a reaction mediated by peroxidases. Here, we report the existence of a relationship between the Σβ-O-4/ΣO-4 end monomer ratio of the linear lignin fraction, released through the specific cleavage of the alkyl ether linkages by thioacidolysis, and the G/S ratio of lignins, when this was estimated in differentially evolved vascular land plants. Most importantly, in the case of angiosperms, Gnetales, and lycopods, the Σβ-O-4/ΣO-4 end monomer ratio was apparently predictable from the proportions at which the G and S units were mixed. In the case of G lignins (present in basal gymnosperms and ferns), the Σβ-O-4/ΣO-4 end monomer ratio decayed exponentially to increase the O-4-linked dihydroconiferyl alcohol (DHCA) content. The results obtained suggest that the Σβ-O-4/ΣO-4 end monomer ratio of the linear lignin fraction depends intimately on the lignin monomer composition, and, therefore, on the chemical nature of the radicals derived from three monolignols (coniferyl, dihydroconiferyl, and sinapyl alcohols), whose gain have been finely tuned during land plant evolution.