Diels-Alder Type Adducts Research Articles

Two new Diels–Alder-type adducts from the stem barks of Morus yunanensis

Two new Diels–Alder adducts, yunanensins B and D (1 and 2), were isolated from the stem bark of Morus yunanensis. Their structures were determined by spectroscopic analysis. Compounds 1 and 2 showed moderate antioxidant effects on liver microsomal lipid peroxidation induced by Fe2+-Cys system, with inhibitory ratios of 57.1% and 67.9% at a concentration of 10− 5 mol/l.

Phosphodiesterase I-Inhibiting Diels-Alder Adducts from the Leaves ofMorus mesozygia

A new 2-arylbenzofuran derivative, (+)-dimethylsmoracin O (1), and three new Diels-Alder type adducts, mesozygins A–C (2–4), in addition to eight known compounds, artonin I (5), chalcomaracin (6), norartocarpetin (7), moracin L (8), mulberrofuran F (9), moracin M (10), moracin C (11), and morachalcone A (12),were isolated from the leaves of Morus mesozygia Stapf. Structures were elucidated by spectroscopic data analyses. Compounds 2-7 displayed a potent phosphodiesterase I inhibitory activity.

Melicodenines A and B, novel Diels–Alder type adducts isolated from Melicope denhamii

Two novel Diels–Alder type adducts, melicodenines A ( 1) and B ( 2), were isolated from the leaves of Melicope denhamii (Seem.) T. G. Hartley and their structures were established by spectroscopic analyses, including extensive 2D NMR experiments. Compound 1 is a bisquinolinone alkaloid comprised of two N-methylflindersines ( 3), while compound 2 is the first naturally occurring quinolinone–acetophenone conjugate composed of 3 and an evodionol methyl ether ( 4).

Sanggenon C and O inhibit NO production, iNOS expression and NF-κB activation in LPS-induced RAW264.7 cells

Objective: The NO production through the iNOS induction by activation of nuclear factor (NF-κB) is known to involve in various inflammatory conditions. Sanggenon C and O, two Diels-Alder type adducts isolated from Morus alba, a plant has been used for the anti-inflammatory purpose in the Oriental medicine, were investigated for their effect on the NO production, iNOS expression and NF-κB activity.Methods: The inhibitory effects of sanggenon C and O on the NF-κB activity were investigated in LPS-stimulated RAW264.7 cells by SEAP reporter assay. The regulation of the iNOS expression and IκBα activation by two compounds was also evaluated by Western blot.Results: Both compounds strongly inhibited NO production and NF-κB activation in a dose-dependent manner. The expression of the iNOS protein was also suppressed by treatment of the compounds (10 and 1 µM). Sanggenon O showed stronger inhibition than the diastereomer sanggenon C. Both compounds prevented the phosphorylation and degradation of IκBα protein.Conclusion: We demonstrated that sanggenon C and O inhibited NO production and iNOS expression by suppressing NF-κB activity and IκBα activation.

UV-B Induced Changes in the Secondary Metabolites of Morus alba L. Leaves

Ultraviolet-B (UV-B) radiation is harmful to plants and human beings. Many secondary metabolites, like flavonoids, alkaloids, and lignin, are UV-B absorbing compounds, which can protect the genetic material of plants. Furthermore, they are active components of herbal drugs. UV-B radiation can activate the self-protective secondary metabolism system. The results of this paper provide a method to induce bioactive secondary metabolites from mulberry leaves (Morus alba L.) by UV-B irradiation in vitro. Five significantly different chromatographic peaks were found by HPLC fingerprint after induction, from which two active compounds were identified: One was chalcomoracin, a natural Diels-Alder type adduct with antibacterial activity; the other one was moracin N, which is a precursor of chalcomoracin. Their contents were 0.818 mg/g and 0.352 mg/g by dry weight, respectively.

Bioactive constituents of Morus wittiorum

From the stem bark of Morus wittiorum, one new Diels–Alder type adduct wittiorumin G ( 1) and three new 2-arylbenzofuran derivatives wittifurans P–R ( 2– 4) along with five known Diels–Alder type adducts albafuran C, sorocein A, mulberrofuran E, mulberrofuran F and mulberrofuran O were isolated. Their structures were determined on the basis of spectroscopic analysis. Compounds 2– 4 and two known compounds sorocein A and mulberrofuran F were evaluated for their antioxidant activity in a Fe 2+/cysteine-induced microsomal lipid peroxidation assay and cytotoxicity against five human cancer cell lines respectively.

Three new Diels–Alder type adducts from the stem bark of Morus cathayana

Three new Diels–Alder type adducts cathayanons C (1), D (2), and E (3), together with one known compound sanggenon C (4), were isolated from the stem bark of Morus cathayana. Their structures were fully elucidated by spectroscopic and chemical methods. Compound 2 showed good anti-oxidation activity with the inhibitory rate of malondialdehyde being 88% at a concentration of 10− 6 mol/l.

Chemistry and biosynthesis of isoprenylated flavonoids from Japanese mulberry tree

Many isoprenylated flavonoids have been isolated from Japanese mulberry tree (Moraceae). Among them, kuwanons G (1) and H (2) were the first isolated active substances exhibiting a hypotensive effect. These compounds are considered to be formed through an enzymatic Diels-Alder type reaction between an isoprenyl portion of an isoprenylphenol as the diene and an α, β-double bond of chalcone as the dienophile. The absolute configurations of these Diels-Alder type adducts were confirmed by three different methods. The stereochemistries of the adducts were consistent with those of ones in the Diels-Alder reaction involving exo- and endo-addition. Some strains of Morus alba callus tissues have a high productivity of mulberry Diels-Alder type adducts, such as chalcomoracin (3) and kuwanon J (4). The biosynthetic studies of the mulberry Diels-Alder type adducts have been carried out with the aid of the cell strain. Chalcomoracin (3) and kuwanon J (4) were proved to be enzymatic Diels-Alder type reaction products by the administration experiments with O-methylchalcone derivatives. Furthermore, for the isoprenoid biosynthesis of prenylflavonoids in Morus alba callus tissues by administration of [1,3-13C2]- and [2-13C]-glycerol, a novel way through the junction of glycolysis and pentose-phosphate cycle was proved. Two independent isoprenoid biosynthetic pathways, that for sterols and that for isoprenoidphenols, operate in the Morus alba cell cultures. The former is susceptible to compactin (ML-236) and the latter resists to compactin in the cell cultures, respectively.

A new Diels–Alder type adduct and two new flavones from the stem bark of Morus yunanensis Koidz

Fractionation of the ethanolic extract of the stem bark of Morus yunanensis resulted in the isolation of a new Diels–Alder type adduct and two new flavones, named yunanensin A (1), yunanensol A (2) and yunanensol B (3), respectively, together with a known flavone (4). Their structures were determined on the basis of spectroscopic analysis and chemical methods. Among them, compound 1 showed moderate antioxidant and significant cytotoxic activities, and compound 2 showed potent anti-inflammatory activity.

A new anti-oxidant Diels-Alder type adduct from Morus macroura

A new Diels-Alder type adduct, named guangsangon O, was isolated from Morus macroura Miq., and its structure was determined by means of spectroscopic analyses and chemical methods. The isolated new compound showed potent anti-oxidant activity in vitro.

Five New Diels-Alder Type Adducts from the Stem and Root Bark ofMorus mongolica

Five new Diels-Alder type adducts, mongolicins A - E, and nine known compounds, mongolicin F, chalcomoracin, mulberrofuran T, mulberrofuran G, mulberrofuran F, albanol B, kuwanon O, mulberrofuran H and kuwanon H, were isolated from the stem and root bark of Morus mongolica. Their structures were determined by spectroscopic analysis and chiroptical methods. Among them, compounds and showed potent anti-inflammatory activities (inhibition of release of beta-glucuronidase from rat PMNs induced by PAF) with inhibitory ratios of 80.4% (P<0.05) and 77.0% (P<0.001) at a concentration of 10(-5) mol L-1. Compounds and were active as antioxidatives (inhibition of liver microsomal lipid peroxidation induced by Fe2+-Cys system) with inhibitory ratios of 83.6% (P<0.05), 86.0% (P<0.05), and 63.0% (P<0.05) at a concentration of 10(-5) mol L-1.

New Diels—Alder Type Adducts from Morus macroura and Their Antioxidant Activities.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Guangsangons F–J, anti-oxidant and anti-inflammatory Diels–Alder type adducts, from Morus macroura Miq.

Five Diels–Alder type adducts, named guangsangons F, G, H, I, and J, along with two known compounds, mulberrofuran J and kuwanon J, were isolated from Morus macroura Miq. Their structures were determined by means of spectroscopic analyses and chemical methods. These compounds were regarded biogenetically as Diels–Alder type adducts of dehydroprenylphenols and chalcone derivatives, and 1H NMR variable temperature experiments suggested that they all existed as an equilibrium mixture of conformational isomers in solution. Among the isolated new compounds, guangsangons H, I, and J displayed potent antioxidant activities and moderate anti-inflammatory activities.

New Diels-Alder type adducts from Morus macroura and their anti-oxidant activities.

Fractionation of the ethanolic extract of the stem bark of Morus macroura resulted in the isolation of four new Diels-Alder type adducts, named guangsangons K--N (1, 2, 5, 6), together with two known compounds, mulberrofuran G (3) and K (4). Their structures were determined on the basis of spectroscopic analyses and chemical methods. Furthermore, by means of (1)H-NMR variable temperature experiments and the Cotton curves in the circular dichroism (CD) spectra, the stereochemistry of four new compounds was elucidated. The isolated new compounds showed good activity on anti-oxidant in vitro, with the inhibitory rates of MDA being from 91.8 to 100.0% at concentrations of 10(-5) mol/l.

Sorocein L and sorocein M: two Diels-Alder type adducts from Sorocea ilicifolia.

Two new Diels-Alder type adducts, named sorocein L (1) and sorocein M (2), together with the known kuwanon J and mulberrofuran O, were isolated from the methanolic extract of the roots of Sorocea ilicifolia. Sorocein L shows the same substitution pattern of sorocein M and corresponds to its ketalized derivative.

Diels–Alder type adducts from Morus cathayana

Two natural Diels–Alder type adducts, cathayanon A (1) and cathayanon B (2), resembling sanggenon C (4) and O (3), were isolated from the root bark of Morus cathayana. Their structures were elucidated on the basis of spectroscopic evidence. The structure of 1 was confirmed by the results of X-ray crystallographic analysis. The absolute configurations of 1 and 2 were determined as 2S, 3R,14S, 19S, 20R and 2S, 3R, 14R, 19S, 20R, respectively. The absolute configurations at C-2 and C-3 of two other known isomeric Diels–Alder adducts sanggenon O (3) and C (4) were deduced as 2R, 3S. Pharmacological tests indicated that 1 and 2 exhibited potent activities on the inhibition of HL-60 cell adhesion to BAEC at concentrations of 10−5 mol l−1, with inhibitory rates of 44.72 and 39.02%, respectively.

プレニールフラボノイドの化学と生合成

Many isoprenylated flavonoids have been isolated from mulberry trees and related plants (Moraceae). Among them, kuwanons G (13) and H (14) were the first isolated active substances exhibiting a hypotensive effect from the Japanese Morus root bark. These compounds are considered to be formed through an enzymatic Diels-Alder reaction of a chalcone (15) and dehydro-kuwanon C (16) or its equivalent. Since that time, about forty kinds of Diels-Alder type adducts structurally similar to that of 13 have been isolated from the moraceous plants. Some strains of Morus alba as well as M. bombycis callus tissues have a high productivity of mulberry Diels-Alder type adducts, such as chalcomoracin (26) and kuwanon J (28). The biosynthesis of the mulberry Diels-Alder type adducts has been studied with the aid of the cell strain. Chalcomoracin (26) and kuwanon J (28) were proved to be enzymatic Diels-Alder type reaction products by the administration experiment with O-methylchalcone derivatives. Furthermore, for the isoprenoid biosynthesis of prenylflavonoids in Morus alba callus tissues, a novel way through the junction of glycolysis and pentose-phosphate cycle was proposed. The crude enzyme fraction catalyzing the Morus Diels-Alder type reaction could be isolated. Studies of phenolic constituents of licorice (Glycyrrhiza species) were carried out. On the course of the structure determination of the phenolic constituents of licorice, two new NMR structure determination methods for prenylflavonoids were found. Furthermore, the prenylphenols isolated from licorice were summarized according to the origin of the materials.

ChemInform Abstract: Structure of Sanggenon O, a Diels—Alder Type Adduct Derived from a Chalcone and a Dehydroprenylated Sanggenon‐Type Flavanone from Morus cathayana.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Sorocein I, a new Diels-Alder type adduct from Sorocea ilicifolia

From ethyl acetate extract of the root bark of Sorocea ilicifolia a new ketalized Diels-Alder type adduct, sorocein I (1), was isolated.

ChemInform Abstract: Three Diels—Alder Type Adducts, Ginsenoynes L, M, and N, from the Roots of Panax ginseng.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.