Isoamericanoic Acid B from Acer tegmentosum as a Potential Phytoestrogen.

Phytoestrogens derived from plants have attracted the attention of the general public and the medical community due to their potentially beneficial role in relieving menopausal symptoms. The deciduous tree Acer tegmentosum Maxim (Aceraceae) has long been utilized in Korean folk medicine to alleviate many physiological disorders, including abscesses, surgical bleeding, and liver diseases. In order to explore structurally and/or biologically new constituents from Korean medicinal plants, a comprehensive phytochemical study was carried out on the bark of A. tegmentosum. One new phenolic compound with a 1,4-benzodioxane scaffold, isoamericanoic acid B (1), as well as with nine known phenolic compounds (2⁻10), were successfully isolated from the aqueous extracts of the bark of A. tegmentosum. A detailed analysis using 1D and 2D NMR spectroscopy, electronic circular dichroism (ECD) spectral data, and LC/MS afforded the unambiguous structural determination of all isolated compounds, including the new compound 1. In addition, compounds 2, 4, 5, and 9 were isolated and identified from the bark of A. tegmentosum for the first time. All isolated compounds were tested for their estrogenic activities using an MCF-7 BUS cell proliferation assay, which revealed that compounds 1, 2, and 10 showed moderate estrogenic activity. To study the mechanism of this estrogenic effect, a docking simulation of compound 1, which showed the best estrogenic activity, was conducted with estrogen receptor (ER) -α and ER-ß, which revealed that it interacts with the key residues of ER-α and ER-ß. In addition, compound 1 had slightly higher affinity for ER-ß than ER-α in the calculated Gibbs free energy for 1:ER-α and 1:ER-ß. Thus, the present experimental evidence demonstrated that active compound 1 from A. tegmentosum could be a promising phytoestrogen for the development of natural estrogen supplements.

Isolation and structural characterization of the milled wood lignin, dioxane lignin, and cellulolytic lignin preparations from brewer's spent grain.

The structure of the lignin from brewer's spent grain (BSG) has been studied in detail. Three different lignin preparations, the so-called "milled-wood" lignin (MWL), dioxane lignin (DL), and cellulolytic lignin (CEL), were isolated from BSG and then thoroughly characterized by pyrolysis GC/MS, 2D-NMR, and derivatization followed by reductive cleavage (DFRC). The data indicated that BSG lignin presents a predominance of guaiacyl units (syringyl/guaiacyl ratio of 0.4-0.5) with significant amounts of associated p-coumarates and ferulates. The flavone tricin was also present in the lignin from BSG, as also occurred in other grasses. 2D-NMR (HSQC) revealed that the main substructures present are ß-O-4' alkyl-aryl ethers (77-79%) followed by ß-5' phenylcoumarans (11-13%) and lower amounts of ß-ß' resinols (5-6%) and 5-5' dibenzodioxocins (3-5%). The results from 2D-NMR (HMBC) and DFRC indicated that p-coumarates are acylating the γ-carbon of lignin side chains and are mostly involved in condensed structures. DFRC analyses also indicated a minor degree of γ-acylation with acetate groups, which takes place preferentially on S lignin (6% of S units are acetylated) over G lignin (only 1% of G units are acetylated).

3-deoxysilybin exerts anti-inflammatory effects by suppressing NF-κB activation in lipopolysaccharide-stimulated RAW264.7 macrophages.

3-deoxysilybin (3-DS), also known as (-)-isosilandrin A, is a natural flavonoid of Silybum marianum. This study was designed to investigate the anti-inflammatory effect and the underlying molecular mechanisms of 3-DS in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. 3-DS dose-dependently inhibited the production of NO and the expression of iNOS in LPS-stimulated RAW264.7 macrophages. 3-DS also inhibited the production of pro-inflammatory cytokines (MCP-1, TNF-α, IL-6, and IL-1ß) in LPS-stimulated RAW264.7 macrophages. Moreover, 3-DS decreased the NF-κB DNA binding activity in LPS-stimulated RAW264.7 macrophages. Furthermore, 3-DS suppressed NF-κB activation by inhibiting the degradation of IκBα and nuclear translocation of p65 subunit of NF-κB in LPS-stimulated RAW264.7 macrophages. Taken together, the present study suggests for the first time that 3-DS may exhibit an anti-inflammatory effect through the suppression of NF-κB transcriptional activation in LPS-stimulated RAW264.7 macrophages.

Anti-inflammatory activity of edible brown alga Eisenia bicyclis and its constituents fucosterol and phlorotannins in LPS-stimulated RAW264.7 macrophages.

Although individual phlorotannins contained in the edible brown algae have been reported to possess strong anti-inflammatory activity, the responsible components of Eisenia bicyclis have yet to be fully studied. Thus, we evaluated their anti-inflammatory activity via inhibition against production of lipopolysaccharide (LPS)-induced nitric oxide (NO) and tert-butylhydroperoxide (t-BHP)-induced reactive oxygen species (ROS), along with suppression against expression of inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2), in RAW 264.7 cells. The anti-inflammatory activity potential of the methanolic extract and its fractions of E. bicyclis was in the order of dichloromethane>methanol>ethyl acetate>n-butanol. The strong anti-inflammatory dichloromethane fraction was further purified to yield fucosterol. From the ethyl acetate fraction, six known phlorotannins were isolated: phloroglucinol, eckol, dieckol, 7-phloroeckol, phlorofucofuroeckol A and dioxinodehydroeckol. We found that these compounds, at non-toxic concentrations, dose-dependently inhibited LPS-induced NO production. Fucosterol also inhibited t-BHP-induced ROS generation and suppressed the expression of iNOS and COX-2. These results indicate that E. bicyclis and its constituents exhibited anti-inflammatory activity which might attribute to inhibition of NO and ROS generation and suppression of the NF-κB pathway and can therefore be considered as a useful therapeutic and preventive approach to various inflammatory and oxidative stress-related diseases.

5alpha,8alpha-epidioxysterols from a Formosan sponge, Axinyssa sp.

One new 5alpha,8alpha-epidioxysterol, 3-acetylaxinysterol (1), along with one known sterol, axinysterol (2), were isolated from a Formosan sponge, Axinyssa sp.. The structures of the compounds were determined by spectroscopic methods and the absolute configuration of 2 was further confirmed by single-crystal X-ray diffraction analysis for the first time. Compound 2 exhibited significant cytotoxicity against K562 and Molt 4 cancer cell lines.

Differentiation of human osteosarcoma cells by isolated phlorotannins is subtly linked to COX-2, iNOS, MMPs, and MAPK signaling: implication for chronic articular disease.

Arthritis is one of the most prevalent chronic inflammatory diseases, and it is characterized by structural and biochemical changes in major tissues of the joint, including degradation of the cartilage matrix, insufficient synthesis of extracellular matrix (ECM). Ecklonia cava (EC) is a member of the family of Laminariaceae, which is an edible marine brown alga with various bioactivities. In this study of the methanol extract of brown alga EC, the dieckol (1) and 1-(3',5'-dihydroxyphenoxy)-7-(2'',4'',6''-trihydroxyphenoxy) 2,4,9-trihydroxydibenzo-1,4,-dioxin (2) were isolated and characterized by NMR techniques with high yield. Phlorotannin derivatives (1, 2) promoted osteosarcoma differentiation by increasing alkaline phosphatase (ALP) activity, mineralization, total protein and collagen synthesis in human osteosarcoma cell (MG-63 cells), respectively. Furthermore, these phlorotannin derivatives (1, 2) inhibited mRNA gene and protein levels of matrix metalloproteinase (MMP-1, MMP-3, and MMP-13), iNOS and COX-2 in casein zymography, Western blot and reverse transcriptase-polymerase chain reaction (RT-PCR) assays. In addition, it was observed that the phlorotannins inhibited phosphorylation of JNK and p38 MAPK in human osteosarcoma cell. These results suggested the phlorotannin derivatives (1, 2) could promote cell differentiation, attenuate MMP-1, MMP-3, MMP-13 expressions, and inflammatory response via MAPK pathway in chronic articular diseases.

High-performance liquid chromatographic method for identification and quantification of two isomeric coumarinolignoids-cleomiscosin A and cleomiscosin B-in extracts of Cleome viscosa.

A simple, accurate and reproducible reverse-phase HPLC method has been developed for identification and quantification of two isomeric coumarinolignoids, cleomiscosin A and B in different extracts of the seeds of Cleome viscosa using photodiode array detection at 326 nm. Cleomiscosin A and B were separated on a Waters symmetry C(18) column (250 x 4.6 mm with 5.0 microm particle size) with an isocratic elution system composed of acetonitrile-methanol (1:2, v/v) and acetic acid-water (0.5:99.5, v/v) in the ratio of 40:60 (v/v). The calibration curves were linear (r(2) > 0.997) in the concentration ranges of 20-100 microg/mL for both compounds. The limits of detection and quantification were 15 and 20 microg/mL for both cleomiscosin A and B. The intra- and inter-day precisions were 3.68 and 2.22% for cleomiscosin A and 4.22 and 5.06% for cleomiscosin B. The recoveries measured at two different concentration levels varied from 98.03 to 110.06%. The method was used to identify and quantify cleomiscosins A and B in different extracts of Cleome viscosa seeds.

Chemical constituents from the roots of Homonoia riparia.

A new compound and twelve known compounds were isolated from the ethyl acetate extract of the roots of Homonoia riparia Lour, which are used in folk medicine for treatment of hepatitis, bellyache and scald, by the method of silica gel column chromatography repeatedly with a gradient of PE-EtOAc, PE-Me2CO, CHCl3-Me2CO, CHCl3-MeOH. Their structures were identified as a new compound 1-oxo-aleuritolic acid (1), and twelve known compounds aleuritolic acid (2), 3-acetoxy-aleuritolic acid (3), taraxerone (4), taraxerol (5), methyl 3-acetoxy-12-oleanen-28-oate (6), 3-acetoxy-12-oleanen-28-ol (7), ursolic acid (8), lupenol (9), 3beta-acetoxy-lupenol (10), cleomiscosin A (11), chrysophanol (12), and gallic acid (13), which were obtained from this plant for the first time, by the spectroscopic techniques of NMR, HMBC, IR and MS, separately. Among the cytotoxicities evaluation of compounds 1 -3 towards AGZY 83-a (human lung cancer cells) and SMMC-7721 (human liver cancer cells) tumor cells was assayed by MTT methods with cis-dichlorodiamminoplatinum (DDP) used as positive control. Compound 2 exerted weak activity against AGZY 83-a with the IC50 value of 33.055 microg x mL(-1), while 1 and 3 showed no activity to these two cell lines.

Hyosgerin, a new optically active coumarinolignan, from the seeds of Hyoscyamus niger.

Hyosgerin, a new optically active coumarinolignan, has been isolated and characterized along with three other coumarinolignans, venkatasin, cleomiscosin A and cleomiscosin B, from the seeds of Hyoscyamus niger L. The structure was determined on the basis of spectroscopic analysis and chemical conversion. The optical properties and absolute stereochemistry of these coumarinolignans have also been studied and discussed.

Deoxypreussomerins from Jatropha curcas: are they also plant metabolites?

Three deoxypreussomerins, palmarumycins CP1, JC1 and JC2, have been isolated from a collection of the stems of Jatropha curcas. The second and third compounds are antibacterial constituents which were characterized from spectral evidence. The X-ray crystallographic structure of palmarumycin JC1 was also studied. Deoxypreussomerins have been obtained here from a plant source in appreciable quantities.

Structures of 1,4-benzodioxane derivatives from the seeds of Phytolacca americana and their neuritogenic activity in primary cultured rat cortical neurons.

The methanol extract of the seeds of Phytolacca americana was reinvestigated to yield three new 1,4-benzodioxane-type compounds, americanoic acid methyl ester (1), isoamericanoic acid A methyl ester (2), and 9'-O-methylamericanol A (3) along with the previously isolated neolignans 6-9. The structures of 1-3 were characterized by 2D NMR and long-range selective proton-decoupling (LSPD) techniques. The neuritogenic effects of compounds 1-3, and dicarboxilic acids 4 and 5, which had been previously synthesized with horseradish peroxidase-catalyzed oxidative coupling of caffeic acid, were examined in primary cultured rat cortical neurons. Americanoic acid A methyl ester (1) exhibited neurite outgrowth-promoting activity at concentration of 0.01-1.0 microM, whereas dicarboxilic acids 4 and 5 were found to induce neuritogenesis dose dependently at the concentrations from 0.1 microM to 10 microM.

Coumarins with monoamine oxidase inhibitory activity and antioxidative coumarino-lignans from Hibiscus syriacus.

A previously undescribed coumarin and a new coumarino-lignan, together with the known compounds scopoletin and cleomiscosins A, C, and D, have been isolated from the root bark of Hibiscus syriacus, and their structures were assigned on the basis of various spectral studies. The coumarin analogue and scopoletin inhibited monoamine oxidase with moderate IC(50) values. The new coumarino-lignan and cleomiscosin C showed lipid peroxidation inhibitory activity comparable to vitamin E.

[Studies on the chemical constituents of the seeds from Artabostrys hexapetalus (Annonaceae)].

AIM: To study the chemical constituents of the seeds from Artabotrys hexapetalus (L.f.) Bhandari (Annonaceae). METHODS: Various chromatographic techniques were used to separate and purify the constituents. Their structures were elucidated on the physico-chemical properties and spectral data. RESULTS: Eight compounds were isolated from the seeds of A. hexapetalus. They were identified as four neolignans: isoamericanin A (1), isoamericanol A (2), americanin B (3) and artabotrycinol (4), a semiterpenoid: (R)-artabotriol (5) and others: palmitic acid (6), beta-sitosterol (7) and daucosterol (8). CONCLUSION: Artabotrycinol (4) and (R)-artabotriol (5) are new compounds. Three other neolignans were isolated from this plant for the first time.

Stereostructure and anti-inflammatory activity of three diastereomers of ocobullenone from Ocotea bullata.

A novel diastereomer of ocobullenone. designated as sibyllenone, was isolated from the stem bark of mature Ocotea bullata in the course of a search for anti-inflammatory compounds from this plant. The stereostructure was established by X-ray crystallography and corroborated by NOESY analysis. Ocobullenone, obtained previously, was re-isolated and crystallised successfully for X-ray analysis, thus making possible an accurate spatial comparison of ocobullenone, iso-ocobullenone and the new stereoisomer. Tested pharmacologically for cyclooxygenase-1 and 2, and 5-lipoxygenase inhibition, sibyllenone was the only compound from O. bullata which showed good inhibitory activity towards 5-lipoxygenase.

[Studies on chemical constituents of Stelmatocrypton khasianum (Benth.) H. Bail].

OBJECTIVE: To study the chemical constituents of Stelmatocrypton khasinum. METHOD: Using chromatographic methods to isolate compounds from S. khasinum and chemical and spectral methods to elucidate their structures. RESULT: Eight compounds, cleomiscosin A(1), 4-methoxy salicylicaldehyde(2), vanillin(3), isovanillin(4), 4-methoxy salicylic acid(5), isovanillic acid(6), 2,4-dihydroxy-benzoic acid(7) and 4-hydroxy-benzoic acid(8) were isolated from the stem of S. khasianum. CONCLUSION: Except compound 2, all the compounds were obtained from this plant for the first time.

Plant anticancer agents XXIX. Cleomiscosin A from Simaba multiflora, Soulamea soulameoides, and Matayba arborescens.

Cleomiscosin A (1) has been isolated from Simaba multiflora and Soulamea soulameoides in the Simaroubaceae through bioactivity-directed fractionation and from Matayba arborescens in the Sapindaceae . The structure of cleomiscosin A (1) was established through spectroscopic studies and chemical reactions.