Two new phenanthrenoid dimers from Juncus effusus

Two new phenanthrenoid dimers,named dijuncuenins A (1) and B (2),were isolated from the ethanolic extract of the whole plant of Juncus effusus.Their structures were determined by 1D and 2D NMR spectroscopic analysis and mass spectrometry.The plausible biosynthetic pathways of compounds 1 and 2 were proposed.     

Diterpenoid and Phenolic Compounds from Juncus effusus L.

A novel diterpene, named effusenone A ( 1a ), which is the first reported rosane‐type diterpene from a Juncaceae plant, and three novel phenolic compounds, 5‐(hydroxymethyl)‐1‐methylphenanthrene‐2,7‐diol ( 4 ), 1‐methylpyrene‐2,7‐diol ( 5 ), and 7‐methoxy‐8‐methylpyren‐2‐ol ( 6 ) were isolated from the stem of Juncus effusus L. by normal‐phase and reversed‐phase silica gel column chromatography. Their structures were identified by spectroscopic methods, especially 2D‐NMR techniques.     

Antiproliferative Phenanthrenes from Juncus tenuis: Isolation and Diversity-Oriented Semisynthetic Modification

The occurrence of phenanthrenes is limited in nature, with such compounds identified only in some plant families. Phenanthrenes were described to have a wide range of pharmacological activities, and numerous research programs have targeted semisynthetic derivatives of the phenanthrene skeleton. The aims of this study were the phytochemical investigation of Juncus tenuis, focusing on the isolation of phenanthrenes, and the preparation of semisynthetic derivatives of the isolated compounds. From the methanolic extract of J. tenuis, three phenanthrenes (juncusol, effusol, and 2,7-dihydroxy-1,8-dimethyl-5-vinyl-9,10-dihydrophenanthrene) were isolated. Juncusol and effusol were transformed by hypervalent iodine(III) reagent, using a diversity-oriented approach. Four racemic semisynthetic compounds possessing an alkyl-substituted p-quinol ring (1–4) were produced. Isolation and purification of the compounds were carried out by different chromatographic techniques, and their structures were elucidated by means of 1D and 2D NMR, and HRMS spectroscopic methods. The isolated secondary metabolites and their semisynthetic analogues were tested on seven human tumor cell lines (A2780, A2780cis, KCR, MCF-7, HeLa, HTB-26, and T47D) and on one normal cell line (MRC-5), using the MTT assay. The effusol derivative 3, substituted with two methoxy groups, showed promising antiproliferative activity on MCF-7, T47D, and A2780 cell lines with IC₅₀ values of 5.8, 7.0, and 8.6 µM, respectively.     

Antimicrobial DNA-binding photosensitizers from the common rush,Juncus effusus

Our continuing survey of phototoxins from higher plants has led to the isolation and identification from the common rush, Juncus effusus L., of the phenanthrene, dehydroeffusol (1), and the dihydrophenanthrene, juncusol (2), compounds that display enhanced antimicrobial activities in light. The antimicrobial activities (minimum inhibitory concentrations) for these compounds against methicillin-resistant and -sensitive Staphylococcus aureus and Candida albicans were increased 16- and two-fold, respectively, by irradiation with ultraviolet A (UVA). Photosensitized DNA-binding activities (as possible covalent bond formation) of these compounds were determined by using restriction enzymes and a specially prepared 1.5 kb DNA fragment. Under UVA irradiation, dehydroeffusol strongly inhibited all the restriction enzymes (KpnI, XbaI, PmeI, DraI, PacI and BciVI) that have at least one 5'-TpA sequence in their recognition sites. Weak inhibitions were found for the restriction enzymes EcoRI, SacI, BamHI, SalI, PstI and HindIII, which do not possess a 5'-TpA sequence at their restriction sites and the restriction site sequences of which consist of all bases, A, T, G and C. Trace or no inhibition was found for AscI and SmaI, the restriction site sequences of which are composed of only C and G. The results indicate the necessity of thymine (adenine) for the photosensitized DNA-binding activity of dehydroeffusol. A strong inhibition against SphI, which does not have a 5'-TpA sequence in the restriction sequence, indicates that there are possibly other binding sequence(s) for dehydroeffusol. With juncusol and UVA, strong inhibitions for KpnI and BciVI and trace inhibitions for PacI, XbaI, PmeI and DraI were found. This result also showed a preference of juncusol for 5'-TpA, but the preference could be more selective than that of dehydroeffusol depending on the surrounding sequences of 5'-TpA in the respective restriction sites. A strong inhibition of SphI by juncusol with UVA also indicated the existence of an unknown binding sequence for this compound. Generally, the DNA-binding activity of this compound was weaker than that of dehydroeffusol.     

Phenanthrenes from Juncus atratus with antiproliferative activity

The present study has focused on the isolation and structure determination of phenanthrenes from Juncus atratus Krock. Nine compounds, among them five phenanthrenes, have been isolated from the methanol extract of the plant. Two compounds [juncatrins A (1) and B (2)] are new natural products, three phenanthrenes [juncuenin B (3), effusol (4), and dehydroeffusol (5)], the flavones apigenin (7) and luteolin (8), the diterpene phytol and 13(R)-hydroxy-octadeca-(9Z,11E,15Z)-trien-oic acid (9) were isolated for the first time from the plant. Juncatrin A (1) is substitued with an acetyl group, while in case of juncatrin B (2), an unprecedented acetylene group is connected to the phenanthrene skeleton. The isolated phenanthrenes were evaluated for their antiproliferative activity against HeLa, SiHa and MDA-MB-231 human tumor cell lines. Four phenanthrenes (2, 3, 4 and 5) were more effective [IC₅₀s 3.48?μM (2), 2.91 (3), 3.68 (4), and 7.75?μM (5)] than cisplatin (IC₅₀ 12.43?μM) on HeLa cells.     

Prenylated Benzoic Acids and Phenanthrenes from Liparis Nakaharai

Chemical investigation on the rhizoma of Liparis nakaharai resulted in the isolation of a new phenanthrene, 7‐hydroxy‐2,3,4‐trimethoxyphenanthrene ( 1 ), and three new prenylated benzoic acids, liparacids A ( 2 ), B ( 3 ), and C ( 4 ), together with four known compounds, moscatin, nudol, batatasin III, and 2,5‐dihydroxy‐4‐methoxy‐9,10‐dihydrophenanthrene. The structures of these compounds were elucidated by spectroscopic analysis.     

Dimeric phenanthrenoids from Juncus acutus

Two new dimeric phenanthrenoids have been isolated by the methanol extract of rhizomes of Juncus acutus. The structures have been determined on the basis of their spectroscopic properties and by chemical correlation. The compounds showed in vitro phytotoxicity against Selenastrum capricornutum, a microalga used in aquatic tests.     

Chalcones XI: Potential Germicides Derived from Acetyl Phenanthrenes and Acetophenones

Thirteen phenanthryl and biphenylyl chalcones have been synthesized in presence of saturated solution of Na in methanol to evaluate their germicidal activity against gram +ve and ?ve bacteria.     

Phthalides and other constituents from Ligusticum porteri; sedative and spasmolytic activities of some natural products and derivatives

The chemical constituents of the organic extracts from the rhizomes of Ligusticum porteri were isolated, characterised and identified as Z-ligustilide, Z-butylidenephthalide, diligustilide, tokinolide B, riligustilide, senkyunolides F and I, ferulic acid, among other known compounds. The preparation of 4,5-dehydrotokinolide B from tokinolide B is reported, and its structure confirmed by X-ray analysis. The sedative and spasmolytic activities of some of these natural products and derivatives were evaluated by applying them to in?vivo and in?vitro models. Several of these dimeric phthalides displayed sedative and spasmolytic properties that may correlate with some popular uses of L. porteri.     

Phenanthrenes from Arundina graminifolia and in vitro evaluation of their antibacterial and anti-haemolytic properties

Chemical investigation and activity test of Arundina graminifolia led to the isolation of six phenanthrenes: blestriarene A (1), shancidin (2), densiflorol B (3), ephemeranthoquinone (4), coelonin (5) and lusianthridin (6). The isolated compounds demonstrated antibacterial and anti-haemolytic activities. It was found that compounds 1 and 2 had medium antibacterial activity against Staphylococcus aureus, Bacillus subtilis and Escherichia coli, with MICs of 20–40 μg/mL and MBCs of 40–320 μg/mL. Bactericidal mechanisms were explored. Rupture of cell wall and membrane and leakage of nuclear mass were observed by transmission electron microscopy (TEM). Moreover, compounds 1–3 attenuated the erythrocyte damage. Compounds 1 and 2 showed significant anti-haemolytic activity with inhibition rate about 50% at 16 μg/mL.     

Phenanthrenoids from Juncus acutus L., new natural lipopolysaccharide-inducible nitric oxide synthase inhibitors

The novel natural product juncutol (1), 1,4,7-trimethyl-8,9-dihydro-4H-cyclopenta[def]phenanthrene-2,6-diol, along with the three related metabolites juncusol (2), dehydrojuncusol (3), and 6-hydroxymethyl-1-methyl-5-vinyl-9,10-dihydrophenanthrene-2-ol (4), were isolated from the rhizomes of Juncus acutus L. (Juncaceae) growing in Egypt. The structural identity of 1 was determined on the basis of spectroscopic analyses, including 2D NMR spectroscopy. The inhibitory effect of these natural products on the expression of inducible nitric oxide synthase (iNOS) in lipopolysaccharide-stimulated RAW264.7 macrophage cells was determined for the first time. The unprecedented symmetrical compound juncutol (1) was found to be the most potent inhibitor against the induction of the proinflammatory iNOS protein.     

Phenolic glycosides of Juncus acutus and its anti-eczematic activity

The total alcohol extract of Juncus acutus L. showed significant anti-eczematic activity. The isolation of the five phenolic glycosides which responsible for this activity were isolated and identified as oxyresveratrol 2-O-β-D-glucopyranoside (1), resveratrol 3′,4′-O,O′-di-β-D-glucopyranoside (2), markhamioside F (3), canthoside B (4), and caffeic acid glucorhamnoside (5). The toxic effect of the alcohol extract of the plant was studied on mice to determine their LD₅₀, which proved to be nontoxic up to 3000 mg/kg body weight. The anti-eczematic activity of the isolated compounds was tested in mice and showed variable effect. Compounds 3 and 4 were found to have the highest activity; they cured eczema by 90 and 100% respectively. Published in Khimiya Prirodnykh Soedinenii, No. 2, pp. 125–127, March–April, 2006.     

Designing sedative/hypnotic compounds from a novel substructural graph-theoretical approach

A novel approach to computer-aided molecular design is illustrated. This approach is based on the calculation of the spectral moments of the bond adjacency matrix of graphs representing molecular structures. Spectral moments are then expressed as linear combinations of the different sub-structures present in molecules. Two series of compounds, one containing sedative/hypnotic and the other containing different classes of drugs were used to find a discriminant function with the present approach. Several compounds from the Merck Index were identified by the model as sedative/hypnotic, five of them were found in the recent literature as possessing this activity. The critical fragments, actives and inactive ones, were detected.