Flavonoids from<Emphasis Type="Italic">Spatholobus suberectus</Emphasis>

Two pterocarpans [(6aR,11aR)-maackiain, (6aR,11aR)-medicarpin], one flavanone [(2S)-7-hydroxy-6-methoxy-flavanone], one isoflavan (sativan) and two isoflavones (pseudobaptigenin, genistein) were isolated from the Spatholobus suberectus (Leguminosae). Their chemical structures were determined by comparison of their spectroscopic parameters of CD, EIMS, 1D-NMR and 2D-NMR with those reported in the literatures. All of these compounds are reported for the first time from this plant through the present study.     

Lupinifolin from <Emphasis Type="Italic">Derris reticulata</Emphasis> possesses bactericidal activity on <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> by disrupting bacterial cell membrane

In this study, lupinifolin, a prenylated flavonoid, was isolated from Derris reticulata stem, identified by NMR spectra and confirmed with mass spectrometry. Lupinifolin was freshly prepared by solubilizing in 0.1 N NaOH and immediately diluted in Müller–Hinton broth for antibacterial testing. The data showed that Gram-positive bacteria were more susceptible to lupinifolin than Gram-negative bacteria. Of four strains of Gram-positive bacteria tested, Staphylococcus aureus was the most susceptible. Using the two-fold microdilution method, it was found that lupinifolin possessed antimicrobial activity against S. aureus with minimum inhibitory concentration and minimum bactericidal concentration of 8 and 16 µg/ml, respectively, which is less potent than ampicillin. However, from the time–effect relationship, it was shown that lupinifolin had faster onset than ampicillin. The faster onset of lupinifolin was confirmed by scanning electron microscopy. To investigate the mechanism of action of lupinifolin, transmission electron microscopy (TEM) was performed to observe the ultrastructure of S. aureus. The TEM images showed that lupinifolin ruptured the bacterial cell membrane and cell wall. Due to its fast onset, it is suggested that the action of lupinifolin is likely to be the direct disruption of the cell membrane. This hypothesis was substantiated by the data from flow cytometry using DiOC₂ as an indicator. The result showed that the red/green ratio which indicated bacterial membrane integrity was significantly decreased, similar to the known protonophore carbonyl cyanide 3-chlorophenylhydrazone. It is concluded that lupinifolin inhibits the growth of S. aureus by damaging the bacterial cytoplasmic membrane.     

Antibacterial and synergistic effects of <Emphasis Type="Italic">Smallanthus sonchifolius</Emphasis> leaf extracts against methicillin-resistant <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> under light intensity

Smallanthus sonchifolius (yacon) is a perennial plant mostly cultivated in South America, primarily for use of the tubers as a food crop and the leaves as fodder for livestock. The antibacterial activities of the methanol extract of yacon leaves (S. sonchifolius) and its n-hexane, ethyl acetate, n-butanol and water fractions were evaluated against 6 strains of methicillin-resistant Staphylococcus aureus (MRSA) and 1 standard methicillin-susceptible S. aureus (MSSA) strain by using the disc diffusion method and minimal inhibitory concentrations (MICs) assay in the presence and absence of light. No activity was detected when the two methods were performed without light; however, under illumination at 4000 lux, the n-hexane fraction of yacon (HFY) had a MIC of 15.6 μg/ml. HFYL, prepared by exposure of HFY to 4000 lux for 18 h, was more effective than HFY in terms of antimicrobial activity against the 6 MRSA strains and 1 standard MSSA strain. HFYL mixed with ampicillin or oxacillin showed a synergistic effect with all fractional inhibitory concentrations values being below 0.5. The present study demonstrates the enhancement and antimicrobial activity of yacon leaves against MRSA in the presence of light.     

Assessment of the antibacterial activity of phenylethanoid glycosides from <Emphasis Type="Italic">Phlomis lanceolata</Emphasis> against multiple-drug-resistant strains of <Emphasis Type="Italic">Staphylococcus aureus</Emphasis>

Three phenylethanoid glycosides, forsythoside B (1), phlinoside C (2) and verbascoside (3), were isolated from the methanol extract of the leaves of Phlomis lanceolata, an Iranian medicinal plant, by reversed-phase preparative high-performance liquid chromatography (HPLC), and the structures of these compounds were elucidated conclusively by ultraviolet (UV), mass spectrometry (MS) and a series of 1D and 2D nuclear magnetic resonance (NMR) analyses. The antibacterial properties of 1–3 against five multi-drug-resistant (MDR) strains of Staphylococcus aureus have been assessed by the rapid and robust microtitre-plate-based serial dilution method. While compounds 1 and 3 showed considerable activities against all five strains, compound 2 was inactive at the test concentrations.     

A new <Emphasis Type="Italic">Erythrina</Emphasis> alkaloid from <Emphasis Type="Italic">Erythrina herbacea</Emphasis>

A new Erythrina alkaloid, 10-hydroxy-11-oxoerysotrine (1), has been isolated from the flowers of Erythrina herbacea together with five known compounds: erytharbine (2), 10,11-dioxoerysotrine (3), erythrartine (4), erysotramidine (5) and erysotrine-N-oxide (6). The structure of the new compound was elucidated on the basis of its spectral data, including 2-D NMR and mass (MS) spectra. The new compound is a rare C-10 oxygenated Erythrina alkaloid. The antioxidant activities of the isolated compounds 1–6 were evaluated by scavenging with peroxynitrite.     

Phenolic constituents of <Emphasis Type="Italic">Acorus gramineus</Emphasis>

The purification of a MeOH extract from the rhizome of Acorus gramineus (Araceae) using column chromatography furnished two new stereoisomers of phenylpropanoid, acoraminol A (1) and acoraimol B (2). It also furnished 17 known phenolic compounds, β-asarone (3), asaraldehyde (4), isoacoramone (5), propioveratrone (6), (1′R,2′S)-1′,2′-dihydroxyasarone (7), (1′S,2′S)-1′,2′-dihydroxyasarone (8), 3′,4′-dimethoxycinnamyl alcohol (9), 3′,4′,5′-trimethoxycinnamyl alcohol (10), kaempferol 3-methyl ether (11), 2-[4-(3-hydroxypropyl)-2-methoxyphenoxy]-1,3-propanediol (12), hydroxytyrosol (13), tyrosol (14), (2S,5S)-diveratryl-(3R,4S)-dimethyltetrahydrofuran (15), (7S,8R)-dihydrodehydrodiconiferyl alcohol (16), 7S,8S-threo-4,7,9,9′-tetrahydroxy-3,3′-dimethoxy-8-O-4′-neolignan (17), 7S,8R-erythro-4,7,9,9′-tetrahydroxy-3,3′-dimethoxy-8-O-4′-neolignan (18), and dihydroyashsbushiketol (19). The structures of the new compounds were elucidated by analysis of spectroscopic data including 1D and 2D NMR data. The absolute configurations of 1 and 2 were determined using the convenient Mosher ester procedure. Compounds 5–19 were isolated for the first time from this plant source. The isolated compounds were tested for cytotoxicity against four human tumor cell lines in vitro using a Sulforhodamine B (SRB) bioassay.     

<Emphasis Type="Italic">ent</Emphasis>-Abietane diterpenoids from <Emphasis Type="Italic">Isodon xerophilus</Emphasis>

Three new ent-abietanoids, named xerophilusins XIV–XVI, and four known analogues, as well as four known chemical constituents were isolated from the leaves of Isodon xerophilus. Their structures were elucidated by extensive spectroscopic studies, and comparison with literature data. In addition, the cytotoxic activity of the ent-abietanoids against chronic myelogenous leukemia (K562), stomach adenocarcinoma (MKN45), and hepatocellular carcinoma (HepG2) human cell lines was investigated and no activities were observed.     

Identification of medicinal <Emphasis Type="Italic">Dendrobium</Emphasis> species by phylogenetic analyses using <Emphasis Type="Italic">matK</Emphasis> and <Emphasis Type="Italic">rbcL</Emphasis> sequences

Species identification of five Dendrobium plants was conducted using phylogenetic analysis and the validity of the method was verified. Some Dendrobium plants (Orchidaceae) have been used as herbal medicines but the difficulty in identifying their botanical origin by traditional methods prevented their full modern utilization. Based on the emerging field of molecular systematics as a powerful classification tool, a phylogenetic analysis was conducted using sequences of two plastid genes, the maturase-coding gene (matK) and the large subunit of ribulose 1,5-bisphosphate carboxylase-coding gene (rbcL), as DNA barcodes for species identification of Dendrobium plants. We investigated five medicinal Dendrobium species, Dendrobium fimbriatum, D. moniliforme, D. nobile, D. pulchellum, and D. tosaense. The phylogenetic trees constructed from matK data successfully distinguished each species from each other. On the other hand, rbcL, as a single-locus barcode, offered less species discriminating power than matK, possibly due to its being present with little variation. When results using matK sequences of D. officinale that was deposited in the DNA database were combined, D. officinale and D. tosaense showed a close genetic relationship, which brought us closer to resolving the question of their taxonomic identity. Identification of the plant source as well as the uniformity of the chemical components is critical for the quality control of herbal medicines and it is important that the processed materials be validated. The methods presented here could be applied to the analysis of processed Dendrobium plants and be a promising tool for the identification of botanical origins of crude drugs.     

Cytotoxic constituents of <Emphasis Type="Italic">Amanita subjunquillea</Emphasis>

As part of our systematic study of Korean toxic mushrooms, we have investigated the constituents of Amanita subjunquillea. The column chromatographic separation of the MeOH extract of A. subjunquillea led to the isolation of four ergosterols, two cerebrosides and four cyclopeptides. Their structures were determined by spectroscopic methods to be (22E,24R)-5alpha,8alpha-epidioxyergosta-6,9,22-triene-3beta-ol (1), (22E,24R)-5alpha,8alpha-epidioxyergosta-6,22-dien-3beta-ol (2), (22E,24R)-5alpha,6alpha-epoxyergosta-8,22-diene-3beta,7beta-diol (3), (24S)-ergost-7-en-3beta-ol (4), 8,9-dihydrosoyacerebroside I (5), soyacerebroside I (6), beta-amanitin (7), phalloin (8), alpha-amanitin (9), and phalloidin (10). The compounds 1-6 and 8 were isolated for the first time from this mushroom. The isolated compounds were evaluated for the cytotoxicity against A549, SK-OV-3, SK-MEL-2 and HCT15 cells. Compound 9 exhibited significant cytotoxic activity against A549, SK-OV-3, SK-MEL-2 and HCT15 with ED(50) values of 1.47, 0.26, 1.57 and 1.32 microM, respectively.     

<Emphasis Type="Italic">Perilla frutescens</Emphasis> var. <Emphasis Type="Italic">frutescens</Emphasis> in northern Laos

Twenty-eight samples of mericarps of Perilla frutescens var. frutescens were collected through fieldwork performed in Phongsali and Xieng Khouang provinces in northern Laos. No perilla samples were collected from Savannakhet province in the south although more than 20 sites were investigated. Perilla plants are mostly grown mixed with dry-paddy rice by slash-and-burn cultivation in Laos. The most popular local name for perilla mericarps in the area was “Ma Nga Chan”. Weight of 1,000 grains and hardness of the mericarps were measured, and all mericarps were found to be large (weight of 1,000 grains around 2 g) and soft (limit load weight under 300 g), which were preferred for culinary use in Laos. The composition of the essential oils obtained from the herbaceous plants raised from the mericarps was divided into five types, perillaketone, elemicine plus myristicine, shisofuran, piperitenon, and myristicine, and GC–MS analysis of these Laotian perilla samples showed that they were similar to those of corresponding types of known Japanese perilla strains. One of the shisofuran-type perilla contained large amounts of putative α-naginatene, which is likely to be an intermediate of the biosynthesis of naginataketone. The farmers' indifference to the oil type of the leaf seems to leave Laotian perilla as a good genetic resource for studies of the biosynthesis of oil compounds.     

<Emphasis Type="Italic">In vitro</Emphasis> sortase a inhibitory and antimicrobial activity of flavonoids isolated from the roots of <Emphasis Type="Italic">Sophora flavescens</Emphasis>

A series of flavonoids (1–14) was isolated from the roots of Sophora flavescens. We evaluated their ability to inhibit both microbial growth and sortase A, an enzyme that plays a key role in cell wall protein anchoring and virulence in Staphylococcus aureus. Most prenylated flavonoids (7–13) displayed potent inhibitory activity against gram-positive and gram-negative bacteria except E. coli, with minimum inhibitory concentrations values ranging from 4.40 to 27.7 μM, and weak or no activity against fungal strains tested. Kurarinol (6) was a potent inhibitor of sortase A, with an IC₅₀ value of 107.7 ± 6.6 μM. A preliminary structure-activity relationship, including essential structural requirements, is described.     

<Emphasis Type="Italic">In Vitro</Emphasis> antioxidant and anti-inflammatory activities of Jaceosidin from <Emphasis Type="Italic">Artemisia princeps</Emphasis> Pampanini <Emphasis Type="Italic">cv.</Emphasis> Sajabal

Oxidized low-density lipoprotein (oxLDL) plays a key role in the inflammatory processes of atherosclerosis. Jaceosidin isolated from the methanolic extracts of the aerial parts of Artemisia princeps Pampanini cv. Sajabal was tested for antioxidant and anti-inflammatory activities. Jaceosidin inhibited the Cu²⁺-mediated LDL oxidation with IC₅₀ values of 10.2 μM in the thiobarbituric acid-reactive substances (TBARS) assay as well as the macrophage-mediated LDL oxidation. The antioxidant activities of jaceosidin were exhibited in the conjugated diene production, relative electrophoretic mobility, and apoB-100 fragmentation on copper-mediated LDL oxidation. Jaceosidin also inhibited the generation of reactive oxygen species (ROS) concerning in regulation of NF-κB signaling. And jaceosidin inhibited nuclear factor-kappa B (NF-κB) activity, nitric oxide (NO) production, and suppressed expression of inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS)-induced RAW264.7 macrophages.     

Chemical constituents of <Emphasis Type="Italic">Hypericum erectum</Emphasis> Thunb.

Twenty-two known constituents, including four xanthones, nine flavonoids and nine phenolic glycosides, were isolated from Hypericum erectum Thunb. Their structures were elucidated on the basis of spectral evidence.     

A new class of phenylhydrazinylidene derivatives as inhibitors of <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> biofilm formation

In the struggle against the emergence of the antibiotic resistance, new molecules targeting biofilm formation could be useful as adjuvant of conventional antibiotics. This study focused on a new class of 2-phenylhydrazinylidene derivatives as antivirulence agents. The compound 12e showed interesting activities against biofilm formation of all tested Staphylococcus aureus strains with IC₅₀ ranging from 1.7 to 43 µM; compounds 12f and 13a resulted strong inhibitors of S. aureus ATCC 6538 and ATCC 29213 biofilm formation with IC₅₀ of 0.9 and 0.8 µM, respectively. A preliminary study on the mechanism of action was carried on evaluating the inhibition of sortase A transpeptidase. Compound 12e resulted not to be toxic at 1 mg/ml by using an in vivo model (the wax moth larva model, Galleria mellonella).     

Lignan constituents from <Emphasis Type="Italic">Chloranthus japonicus</Emphasis> Sieb.

A new coumarinolignan glucoside named yinxiancaoside C, along with five known benzofuran lignans, have been isolated from the whole plant of Chloranthus japonicus Sieb. The structures of compounds 1–6 were elucidated by chemical and spectroscopic methods including 1D-NMR, 2D-NMR, ESI-MS and HR-ESI-MS. Five known benzofuran lignans were firstly discovered in the Chloranthaceae. In addition, the cytotoxic activity of the isolated compounds against human hepatoma (Hepg-2), ovarian carcinoma (OV420), and breast cancer (MCF-7) cells was investigated by MTT method.     

Antioxidant activity of red pigments from the lichens <Emphasis Type="Italic">Lethariella sernanderi</Emphasis>, <Emphasis Type="Italic">L. cashmeriana</Emphasis>, and <Emphasis Type="Italic">L. sinensis</Emphasis>

A yellow and new dark red pigments were isolated from Lethariella sernanderi, L. cashmeriana, and L. sinensis as antioxidant components. The yellow pigment was identified as canarione (1), and the others were determined to be 1,2-quinone derivatives, rubrocashmeriquinone (2) and 7-chlororubrocashmeriquinone (3), and 7-chlorocanarione (4) by analysis of their spectroscopic data.     

Biological activity of <Emphasis Type="Italic">Entada phaseoloides</Emphasis> and <Emphasis Type="Italic">Entada rheedei</Emphasis>

The aim of our study is to find functional compounds from natural resources. We focus on plants grown in tropical areas, especially Madagascar and Thailand, because they have unique flora and are expected to contain interesting compounds. We review the functional compounds of the seed kernels of Entada phaseoloides and E. rheedei and their biological activities such as anti-proliferation and melanogenesis inhibitory properties, etc.     

MDMA induces <Emphasis Type="Italic">Per1</Emphasis>, <Emphasis Type="Italic">Per2</Emphasis> and <Emphasis Type="Italic">c-fos</Emphasis> gene expression in rat suprachiasmatic nuclei

Rationale  

±3,4-Methylenedioxymethamphetamine (MDMA, ‘ecstasy’) is a psychoactive drug that has marked effects on the serotonergic system. Serotonergic agonists are known to interact with the circadian pacemaker located in the suprachiasmatic nuclei (SCN).