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PubMed2004

Melanogenesis stimulation in murine B16 melanoma cells by Piper nigrum leaf extract and its lignan constituents.

A methanolic extract from the leaves of Piper nigrum L. showed a significant stimulatory effect on melanogenesis in cultured murine B16 melanoma cells. Activity-guided fractionation of the methanolic extract led to the isolation of two known lignans, (-)-cubebin (1) and (-)-3,4-dimethoxy-3,4-desmethylenedioxycubebin (2), together with a new lignan, (-)-3-desmethoxycubebinin (3). Among these lignans, 1 and 2 showed a significant stimulatory activity of melanogenesis without any significant effects on cell proliferation.

Animals↗

PubMed2003

The anti-HBsAg (human type B hepatitis, surface antigen) and anti-HBeAg (human type B hepatitis, e antigen) C18 dibenzocyclooctadiene lignans from Kadsura matsudai and Schizandra arisanensis.

The C(18) dibenzocyclooctadiene lignans including three novel schizanrin F (1), G (2), H (3), along with the known kadsurarin (4), were isolated from Kadsura matsudai. A new C(19) homolignan named schiarisanrin E (5), together with the known C(18) lignans, gomisin B (6), G (7) and (+)-gomisin K(3) (8) were obtained from Schizandra arisanensis. Gomisin B, G and (+)-gomisin K(3) showed moderate to strong activity for antihepatitis in anti-HBsAg (human type B hepatitis, surface antigen) and/or anti-HBeAg (human type B hepatitis, e antigen) tests. The structural elucidations of new compounds 1-3 and 5 were based on two-dimensional (2D) NMR techniques including COSY, HMQC, HMBC, NOESY and CD spectra. Preliminary structure-activity relationship studies for these isolated lignans are also discussed.

Aspartate Aminotransferases↗

PubMed2003

Arylnaphthalide lignans from Cleistanthus collinus.

Chemical examination of the aerial parts of Cleistanthus collinus afforded the arylanphthalide lignans, cleistanone (1), diphyllin (2), cleistanthins A (3), C (4) and D (5), and 4-O-(3"-O-methyl-beta-D-glucopyranosyl)-diphyllin (6). The first compound is a new member of the rare group of arylnaphthalide lignans containing an alkoxy group on the lactone ring. The structure of the compound was determined from its spectral data, chemical transformations and partial synthesis from diphyllin (2). The new lignan, 1 and its acetyl derivative, 7 were found to exhibit cytotoxicity against MT(2) cell lines.

Acetylation↗

PubMed2004

A new lignan from Balanophora abbreviata and inhibition of lipopolysaccharide (LPS)-induced inducible nitric oxide synthase (iNOS) expression.

Six lignans including a new lignan (1), beta-sitosterol glucopyranoside and phenylpropanoids were isolated from the whole plants of Balanophora abbreviata Bl. (Balanophoraceae). Their structures were determined by NMR, MS analysis and other spectroscopic methods. Lignans (1, 2 and 4) showed potent inhibitory activities on the lipopolysaccharide (LPS)-induced inducible nitric oxide synthase (iNOS) expression in RAW 264.7 cells.

Animals↗

PubMed2007

Two new stereoisomers of Tetrahydrofuranoid lignans from the flower buds of Magnolia fargesii.

Two new stereoisomers of tetrahydrofuranoid lignans, 7S,8R,7'S,8'R- (1) and 7R,8S,7'S,8'R-3,4,3',4'-tetramethoxy-9,7'-dihydroxy-8.8',7.O.9'-lignan (2) along with nine known lignans including tetrahydrofuranoids (3, 4) and tetrahydrofurofuranoids (5-11) were isolated from a CHCl(3)-soluble fraction of the flower buds of Magnolia fargesii. Two tetrahydrofuranoids, magnostellin A (3) and lariciresinol dimethyl ether (4) were isolated from this species for the first time. The structures of these compounds (1-11) were identified by spectroscopic methods as well as by comparison with published values. Absolute configurations of new stereoisomers (1, 2) were determined by the Mosher's esterification method and Circular Dichroism (CD) studies. All the isolates (1-11) were evaluated for their antioxidant activities using modified superoxide radical-scavenging assay. Compounds 5-8 showed the potent superoxide radical-scavenging activities with the ED(50) values of 19.2, 19.2, 16.5, and 27.7 microM, respectively, as compared with standard antioxidants (BHA: 22.8 microM; Trolox: 940 microM).

Circular Dichroism↗

PubMed1995

Inhibition of 5 alpha-reductase in genital skin fibroblasts and prostate tissue by dietary lignans and isoflavonoids.

Isoflavonoids and lignans, constituents of many plant foods, have been proposed as protective agents in those populations with a low incidence of hormone-dependent cancers. They may act by their inhibition of the metabolism of growth-promoting steroid hormones. This report describes the inhibition of 5 alpha-reductase and 17 beta-hydroxysteroid dehydrogenase by six isoflavonoids and two lignans in human genital skin fibroblast monolayers and homogenates, and in benign prostatic hyperplasia tissue homogenates. In genital skin fibroblasts, genistein, biochanin A and equol were the most potent inhibitors of 5 alpha-reductase activity, each resulting in greater than 80% inhibition at a concentration of 100 microM. The IC50 values for genistein and a seven-compound mixture were approximately 35 microM and 20 microM (2.9 microM of each compound) respectively. Of the lignans, enterolactone was the most potent inhibitor. Inhibition by biochanin A was shown to be reversible. When genital skin fibroblast homogenates were used, biochanin A was found to inhibit 5 alpha-reductase isozymes 1 and 2 to differing extents (30% and 75% respectively). Genistein was shown to inhibit 5 alpha-reductase 2 in a non-competitive nature (Vmax and Km values without and with inhibitor were 30 and 20 pmol/mg protein per h and 177 and 170 nM respectively). All of the compounds tested inhibited 17 beta-hydroxysteroid dehydrogenase activity in genital skin fibroblast monolayers. When prostate tissue homogenates were used, the compounds tested were better inhibitors of 5 alpha-reductase 1 than 2.(ABSTRACT TRUNCATED AT 250 WORDS)

17-Hydroxysteroid Dehydrogenases↗

PubMed1993

Quantitative determination of lignans and isoflavonoids in plasma of omnivorous and vegetarian women by isotope dilution gas chromatography-mass spectrometry.

The first quantitative method for the determination of both lignans and isoflavonoid phytoestrogens in plasma is presented. Using ion-exchange chromatography the diphenols are separated into two fractions 1) the biologically "active" fraction containing the free compounds + mono- and disulfates and 2) the biologically "inactive" fraction containing the mono- and diglucuronides and the sulfoglucuronides. After hydrolysis the fractions are further purified by solid phase extraction and ion exchange chromatography. Losses during the complete procedure are corrected for using radioactive estrogen conjugates during the first steps and later by adding deuterated internal standards of all compounds measured (matairesinol, enterodiol, enterolactone, daidzein, O-desmethylangolensin, equol, and genistein). The final determination is carried out by isotope dilution gas chromatography-mass spectrometry in the selected ion monitoring mode (GC/MS/SIM). The diphenols may be measured at concentrations as low as 0.2 to 1.0 nmol/l. Results of plasma analyses of all compounds in 27 pre- and postmenopausal omnivorous and vegetarian women are presented for the first time. The most important findings are that the free+sulfate fraction is low for genistein (3.8% of total), but as much as 21-25% of enterolactone and enterodiol occurs in this fraction. A good correlation between plasma and urine values was found. Total concentrations of individual compounds vary greatly between the subjects (from pmol/l to mumol/l), the vegetarians having higher values, particularly one vegan subject. The highest total enterolactone concentration value exceeded 1 mumol/l. It is concluded that a highly specific method for the assay of 3 lignans and 4 isoflavonoids in plasma has been developed. This method will be useful in future studies of lignan and isoflavonoid metabolism.

Diet, Vegetarian↗

PubMed1999

[Determination of lignan glycosides in the roots of Gaultheria yunnanensis Rehd. by HPLC].

OBJECTIVE: To determine the contents of four lignan glycosides in the root of Gaultheria yunnanensis, namely, D1: gaultheroside A, D2:(-)-8'-methoxyisolariciresinol-2a-O-beta-D-xylopyranoside, D3:(-)-isolariciresinol-2a-O-beta-D-xylopyranside, D4:(+)-lyoniresinol-2a-O-beta-D-glucoxylopyranoside. METHOD: Rp-HPLC was used to separate and analyze the lignan glycosides in the root of the title plant. RESULT: The method for sample preparation was set up; the gradient program for the mobile phase was established; and the retention times of four lignan glycosides were determined. CONCLUSION: The method has been proved to be accurate, reproducible and of higher recovery rate.

Chromatography, High Pressure Liquid↗

PubMed2003

[Studies on the lignans from Patrinia scabra].

AIM: To study the lignans from Patrinia scabra Bunge. METHODS: The constituents were separated and purified by column chromatography with silical gel, RP-silical gel and Sephadex LH-20. Their structures were identified on the basis of spectral data (IR, MS, 1HNMR, 13CNMR, HMQC and HMBC). RESULTS AND CONCLUSION: A new lignan was obtained and its structure was elucidated as 4-[1-ethoxyl-1-(4-hydroxy-3-methoxy)benzyl]methyl- 2-(4-hydroxy-3-methoxy)benzyl-3-hydroxymethyl-tetrahydro-furan (2), along with three known lignans, lariciresinol (1), isolariciresinol (3) and nortracheloside (4).

Furans↗

PubMed1991

Formation of lignans (-)-secoisolariciresinol and (-)-matairesinol with Forsythia intermedia cell-free extracts.

In vivo labeling experiments of Forsythia intermedia plant tissue with [8-14C]- and [9,9-2H2,OC2H3]coniferyl alcohols revealed that the lignans, (-)-secoisolariciresinol and (-)-matairesinol, were derived from two coniferyl alcohol molecules; no evidence for the formation of the corresponding (+)-enantiomers was found. Administration of (+-)-[Ar-3H]secoisolariciresinols to excised shoots of F. intermedia resulted in a significant conversion into (-)-matairesinol; again, the (+)-antipode was not detected. Experiments using cell-free extracts of F. intermedia confirmed and extended these findings. In the presence of NAD(P)H and H2O2, the cell-free extracts catalyzed the formation of (-)-secoisolariciresinol, with either [8-14C]- or [9,9-2H2,OC2H3]coniferyl alcohols as substrates. The (+)-enantiomer was not formed. Finally, when either (-)-[Ar-3H] or (+-)-[Ar-2H]secoisolariciresinols were used as substrates, in the presence of NAD(P), only (-)- and not (+)-matairesinol formation occurred. The other antipode, (+)-secoisolariciresinol, did not serve as a substrate for the formation of either (+)- or (-)-matairesinol. Thus, in F. intermedia, the formation of the lignan, (-)-secoisolariciresinol, occurs under strict stereochemical control, in a reaction or reactions requiring NAD(P)H and H2O2 as cofactors. This stereoselectivity is retained in the subsequent conversion into (-)-matairesinol, since (+)-secoisolariciresinol is not a substrate. These are the first two enzymes to be discovered in lignan formation.

Butylene Glycols↗

PubMed1989

[Determination of Lignans in the fruits of Schisandra chinensis (Trucz.) Baill. and S. Sphenanthern Rehd. et Wils. using HPLC and their chromatograms].

The lignans contained in the fruits of Schisandra chinensis and S. sphenanthern were determined by HPLC. Their chromatograms are different. 7 samples of S. chinensis from 6 habitats contain the same lignans, but in different quantity, while 16 samples of S. sphensnthern contain lignans different both in quality and quantity.

Antineoplastic Agents, Phytogenic↗

PubMed1994

Determination of lignans and isoflavonoids in plasma by isotope dilution gas chromatography-mass spectrometry.

A quantitative method based on ion-exchange chromatography and isotope dilution gas chromatography-mass spectrometry using deuterated internal standards for the determination of plasma lignans and isoflavonoid phytoestrogens has been developed. These compounds are potential anticancer compounds originating from the diet. The method allows the assay of seven different compounds, while unconjugated (free) and sulfated compounds are determined separately from glucuronides and sulfoglucuronides. Results of plasma analyses in Finnish women and in Japanese men are presented. Total concentrations of individual compounds vary greatly between the subjects (from pmol/l to mumol/l), with the Finnish vegetarians and Japanese subjects having higher values. The Finns have relatively high lignan and the Japanese very high isoflavonoid values. It is concluded that the new method allows the determination of the whole plasma lignan and isoflavonoid phytoestrogen profile.

Female↗

PubMed1977

Cytotoxic agents from Bursera morelensis (Burseraceae): deoxypodophyllotoxin and a new lignan, 5'-desmethoxydeoxypodophyllotoxin.

The isolation and identification of deoxypodophyllotoxin and a new lignan, 5'-desmethoxydeoxypodophyllotoxin, from the dried exudate of Bursera morelensis (Burseraceae) are reported. Deoxypodophyllotoxin showed high activity in the KB and PS test systems; the new lignan, although highly active against the KB test system, demonstrated only marginal activity against the PS test system. A structure is suggested for the new lignan, which was named morelensin.

Animals↗

PubMed2005

Regiocontrolled benzannulation of diaryl(gem-dichlorocyclopropyl)methanols for the synthesis of unsymmetrically substituted alpha-arylnaphthalenes: application to total synthesis of natural lignan lactones.

[reaction: see text] An efficient synthesis of highly substituted alpha-arylnaphthalene analogues has been developed utilizing Lewis acid-promoted regiocontrolled benzannulation of aryl(aryl')-2,2-dichlorocyclopropylmethanols (aryl not equal aryl'; abbreviated as AACMs). Both AACM diastereomers were easily prepared via highly stereoselective addition (>95/5) of ArLi to gem-dichlorocyclopropropyl aryl' ketones. The choice of Lewis acids determined the cyclization regioselectivity of the present benzannulation. TiCl4 and SnCl4 used the chelation pathway, whereas silyl triflates used a nonchelation pathway to give unsymmetrically substituted regioisomeric alpha-arylnaphthalenes in 40-91% yields with moderate to excellent regioselectivity (TiCl4 or SnCl4; >99/1-3/1, TBDMSOTf; >1/99-1/4). Thus, the alpha-aryl or alpha-aryl' moiety (accessory aryl group) was alternatively introduced to alpha-arylnaphthalenes by choosing either the order of the reaction sequences or the appropriate catalyst. Application of the present method to the total synthesis for unsymmetrically substituted natural lignan lactones, justicidin B, retrojusticidin B, dehydrodesoxypodophyllotoxin, and a related analogue, 5'-methoxyretrochinensin, was demonstrated. Lignan retrolactones (retrojusticidin B and 5'-methoxyretrochinensin) were synthesized by the conventional lactonization of the diol precursor, whereas a novel Bu2SnO-mediated monoacylation method was applied to the synthesis of normal lignan lactones (justicidin B and dehydrodesoxypodophyllotoxin).

Lactones↗

PubMed1998

Lignans interfering with 5 alpha-dihydrotestosterone binding to human sex hormone-binding globulin.

The natural lignans (-)-3,4-divanillyltetrahydrofuran (1), (-)-matairesinol (2), (-)-secoisolariciresinol (3), (+/-)-enterolactone (4), (+/-)-enterodiol (5), and nordihydroguaiaretic acid (NDGA) (6) reduce the binding of 3H-labeled 5 alpha-dihydrotestosterone (DHT) to human sex hormone-binding globulin (SHBG). (-)-3,4-Divanillyltetrahydrofuran (1) has the highest binding affinity (Ka = 3.2 +/- 1.7 x 10(6)M-1) of all lignans investigated so far; the reversibility of its binding and a double reciprocal plot suggest a competitive inhibition of the SHBG-DHT interaction. Increasing hydrophobity in the aliphatic part of the lignans (butane-1,4-diol-butanolide-tetrahydrofuran structures) leads to higher binding affinity. In the aromatic part, a 3-methoxy-4-hydroxy substitution pattern is most effective for binding to SHBG.

Charcoal↗

PubMed2006

Podophyllum hexandrum Offers Radioprotection by Modulating Free Radical Flux: Role of Aryl-Tetralin Lignans.

We have evaluated the effect of variation in aryl-tetralin lignans on the radioprotective properties of Podophyllum hexandrum. Two fractionated fractions of P. hexandrum [methanolic (S1) and chloroform fractions (S2)], with varying aryl-tetralin lignan content were utilized for the present study. The peroxyl ion scavenging potentials of S1 and S2 were found to be comparable [i.e. 45.88% (S1) and 41% (S2)] after a 48 h interval in a time-dependent study, whereas in a 2 h study, S2 exhibited significant (P < 0.05) antioxidant activity in different metal ion + flux states. In the aqueous phase, S2 exhibited non-site-specific reactive oxygen species scavenging activity, i.e. 73.12% inhibition at 500 mug ml(-1). S1 exhibited 58.40 +/- 0.8% inhibition (at 0.025 mug ml(-1)) of the formation of reactive nitrite radicals, comparable to S2 (52.45 +/- 0.825%), and also showed 45.01% site-specific activity (1000 mug ml(-1)), along with significant (P < 0.05) electron donation potential (50-2000 mug ml(-1)) compared to S2. Such activities of S1 could be attributed to the significantly (P < 0.05) higher levels of podophyllotoxin beta-d-glucopyranoside (16.5 times) and demethyl podophyllotoxin glucoside (2.9 times) compared with S2. Together, these findings clearly prove that aryl-tetralin lignan content influences the radiation protective potential of the Podophyllum fractions to a great extent.

Journal Article↗

PubMed1987

Determination of the aryltetralin lignan content of podophyllum resins and roots/rhizomes.

A simple, quantitatively reproducible method for determining the aryltetralin lignan content of the resins and roots/rhizomes of Podophyllum hexandrum and P. peltatum is described. The method confirms that P. hexandrum resins and roots/rhizomes contain approximately four times the quantity of lignans as do those of P. peltatum and also that there is a significant variation in the lignan content of P. hexandrum resins.

Chromatography, Thin Layer↗

PubMed1992

Platelet activating factor (PAF) antagonists contained in medicinal plants: lignans and sesquiterpenes.

Hot aqueous extracts of medicinal plants were tested for their inhibitory effect on the binding of platelet activating factor (PAF) to rabbit platelets. The extracts of Forsythia suspensa VAHL. (Oleaceae), Arctium lappa L. (Compositae) and Centipeda minima (L.) A. BRAUN et ASCHERS (Compositae) showed significant activities. Since the main constituents of F. suspensa and A. lappa are lignans, 30 lignans were tested for their inhibitory effects on PAF binding to platelets and 9 lignans were found active. Four sesquiterpenes were isolated as active compounds from C. minima. In particular 6-O-angeloylplenolin and 6-O-senecioyplenolin are the most potent and specific PAF antagonists found in this study.

Lignin↗