Antimicrobial DNA-binding Photosensitizers from the Common Rush, Juncus effusus¶

Abstract

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 fromJuncus effususwith anxiolytic and sedative activities

“…A few studies have documented the bioactive constituents of J. effusus (Della Greca et al, 1993;Della Greca, Fiorentino, Monaco, Previtera, & Sorrentino, 1998;Hanawa, Okamoto, & Towers, 2002), but the constituents contributing to its traditional usage are undetermined. In one of our pilot studies, the ethanol extract of J. effusus was separated into four fractions according to sequential elution with petroleum ether, chloroform, ethyl acetate and methanol.…”

Phenanthrenoids from Juncus acutus L., New Natural Lipopolysaccharide-Inducible Nitric Oxide Synthase Inhibitors

“…The UV spectrum of 1 in MeOH showed an intense l max (log e) at 212 (4.34), 285 (4.04), and 296 sh (4.02) nm, which were found to be similar to those of juncusol (2). 8 2 Hz) attributable to two chemically equivalent aromatic methyls and one secondary methyl, respectively. Moreover, two pairs of chemically equivalent aromatic methine (d H 6.74, 2H, s) and benzylic methylene (d H 3.02, 4H, s) protons were also deduced from the 1 H-NMR spectrum of 1.…”

“…A wide range of biological activities such as cytotoxicity, 1,2) antitumor, 3) antialgal, [4][5][6][7]9) antimicrobial, and DNA-binding photosentizing antimicrobial 8) have been reported for Juncus phenanthrenoids. Although the phenanthrenoid-rich plant J. effusus is used traditionally in Japan, China, and Taiwan as an antipyretic and antiphlogistic agent, 8,10) no antiinflammatory studies have been reported of its phenanthrenoids. Our chemical investigation of the rhizomes of J. acutus L. (Juncaceae) growing in Egypt has led to the isolation of a novel phenanthrenoid, juncutol (1), along with three related compounds (2-4).…”

Diterpenoid and Phenolic Compounds from Juncus effusus L.

“…Many phenanthrenoids [3], cycloartane triterpenes [4], and benzocoumarins [5] were isolated from those plants, and phenanthrenoids were major bioactive compounds which showed cytotoxic, antimicrobial and antialgal activities [3]. Recently, it was found that dehydroeffusol (¼ 5-ethenyl-1-methylphenanthrene-2,7-diol) isolated from J. effusus L. displayed photosensitizing activity against some microbes and photosensitized DNA-binding activity, and it represented a novel type of photosensitizers from plants [6]. Those interesting activities have prompted us to reinvestigate the constituents of J. effusus L. As a result, 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), 1methylpyrene-2,7-diol (5), and 7-methoxy-8-methylpyren-2-ol (6) were isolated from the medullae of Juncus effusus L. by normal-phase and reversed-phase silica gel column chromatography.…”