Composition and alpha-amylase inhibitory effect of essential oils from Cedrus libani

The inhibitory activity of alpha-amylase and the phytochemical composition of Cedrus libani essential oils obtained from wood, leaves and cones were investigated. The C. libani woods oil exhibit an IC(50) value of 0.14 mg/ml, whereas the leaves and cones oils were devoid of any significant activity.     

Phenolics from Bidens bipinnata and their amylase inhibitory properties

A new chlorinated flavonoid, 3, 6, 8-trichloro-5, 7, 3', 4'-tetrahydroxyflavone (1), a new biscoumaric acid derivative, 4-O-(2″, 3″-O-diacetyl-6″-O-p-coumaroyl-β-d-glucopyranosyl)-p-coumaric acid (2), and 8, 3', 4'-trihydroxyflavone-7-O-β-d-glucopyranoside (3) together with twenty-four known compounds (4-27) were isolated from the whole plant of Bidens bipinnata. All chemical structures were established on the basis of UV-, MS- and NMR ((1)H, (13)C, (1)H-(1)H COSY, HMQC and HMBC) spectroscopic data. Some of the isolated compounds were tested for the inhibition of α-amylase. The result showed that isookanin (6) was a potent inhibitor of α-amylase (IC(50)=0.447mg/ml).     

Swietenine: A potential oral hypoglycemic from Swietenia macrophylla seed

Swietenine, a tetranortriterpenoid, was isolated from the Swietenia macrophylla seeds. The in vivo hypoglycemic activity was evaluated against neonatal-streptozotocin induced type 2 diabetic rats. Oral administration of swietenine at 25 and 50 mg/kg body weight per day to diabetic rats was found to possess significant dose dependant hypoglycemic and hypolipidemic activity in type 2 diabetic rats.     

Antibacterial activity of plant extracts from Brazilian southeast region

A screening was conducted with 26 plants collected in the Brazilian southeast region, to identify plant extracts with antibacterial properties against Aeromonas hydrophila, Bacillus subtilis, Pseudomonas aeruginosa and Staphylococcus aureus. Initially, the agar diffusion method was employed. Then, those extracts presenting activity were submitted to a broth microdilution assay to determine the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). It was observed that 13 of the tested extracts showed antibacterial activity. The best results were obtained with those from Lantana lilacina and Phyllanthus tenellus.     

New flavane gallates isolated from the leaves of Plicosepalus curviflorus and their hypoglycemic activity

Two new flavane gallates were isolated from the leaves of Plicosepalus curviflorus. The structure of the new compounds was established as 2S,3R-3,3′,4′,5,7-pentahydroxyflavane-5-O-gallate (1) and 2S,3R-3,3′,4′,5,5′,7-hexahydroxyflavane-4′,5-di-O-gallate (2), respectively. In addition, seven known compounds (−)-catechin (3), quercetin (4), lupeol (5), β-sitosterol (6), pomolic acid (7), β-sitosterol 3-O-β-d-glucopyranoside (8) and 4-methoxycinnamic acid (9) were reported for the first time from the genus Plicosepalus. Compounds 1, 2 and 3 were investigated for their hypoglycemic activity and showed significant hypoglycemic activity in Swiss Albino mice.     

Novel indole C-glycosides from Isatis indigotica and their potential cytotoxic activity

Two novel indole C-glycosides, which were the first reported alkaloids C-glycosides from Isatis indigotica, together with five known alkaloids were isolated. The novel alkaloids were elucidated to be indole-3-acetonitrile-4-methoxy-2-C-β-D-glucopyranoside (1) and N-methoxy-indole-3-acetonitrile-2-C-β-D-glucopyranoside (2) on the basis of spectroscopic analysis. 1 exhibited significant cytotoxic activities against human myeloid leukemia HL-60 and human liver cancer HepG2 cells with the IC₅₀ of 1.3 ± 0.1 and 2.1 ± 0.3 μM, respectively. 2 showed potential cytotoxic activities against HL-60 and human myeloid leukemia Mata cells with the IC₅₀ of 5.1 ± 0.4 and 12.1 ± 0.8 μM, respectively.     

Asterosaponins from the starfish Culcita novaeguineae and their bioactivities

Bioassay-guided fractionation of the n-BuOH extract of the starfish Culcita novaeguineae resulted in the isolation of one new sulfated steroidal glycoside (asterosaponin) (1), along with three known asterosaponins, thornasteroside A (2), marthasteroside A(1) (3) and regularoside A (4), as active compounds causing morphological abnormality of Pyricularia oryzae mycelia. Their structures were elucidated by extensive spectral studies and chemical evidences. All the saponins showed moderate cytotoxicity against cancer cell lines K-562 and BEL-7402.     

Flavonoids with prolyl oligopeptidase inhibitory activity isolated from Scutellaria racemosa Pers

Prolyl oligopeptidase (POP) is a serine protease highly expressed in the brain that hydrolyses peptide bonds at the carboxyl terminal of prolyl residues. There is evidence that this enzyme participates in several functions of the central nervous system. Scutellaria racemosa Pers demonstrated significant and selective POP inhibition. Fractionation of the hydroalcoholic extract resulted in the isolation of four main constituents identified for the first time from S. racemosa Pers, the triterpenoid lupeol (1) and the flavonoids oroxylin A (5,7-dihydroxy-6-methoxyflavone, 2), hispidulin (4′,5,7-trihydroxy-6-methoxyflavone, 3), and oroxyloside (oroxylin A 7-O-glucuronide, 4). Inhibitory assays indicated that 3 and 4 at a concentration of 100 μM inhibit 43 and 34% of total POP activity, respectively.     

Potent and selective butyrylcholinesterase inhibitors from Ficus foveolata

Four stilbenes (1-4), one inseparable mixture of two alkyl diferulates (5a, 5b), one alkyl ferulate (6) and four flavonoids (7-10) were isolated from Ficus foveolata Wall. Except for quercetin (10), the other ten constituents were isolated from F. foveolata for the first time. In addition, one of the two components in mixture 5 is a new compound identified as (1E,22E)-1,22-docosanediol diferulate (5a). All nine isolated compounds, plus the mixture of 5a and 5b known as 5, exhibited a low or no activity against acetylcholinesterase. However, and interestingly, the stilbenes 1-4 showed a high inhibition towards butyrylcholinesterase. Gnetol (4) had the lowest IC(50) value of 1.3μM towards butyrylcholinesterase and showed a reversible and competitive inhibition in the kinetic study.     

Sesquiterpenes from the aerial part of Chloranthus japonicus and their cytotoxicities

Four new sesquiterpenes, chlorajapolides F–I (1–4), along with nine known terpenoids (5–13) were isolated from the aerial part of Chloranthus japonicus. Their structures were elucidated on the basis of spectroscopic analysis, and a lindenane sesquiterpene, named 9-hydroxy-heterogorgiolide, previously isolated from the C. japonicus, was revised as its 8-epimer (1a). Moreover, methanol extract (ME), EtOAc fraction (EF), water fraction (WF), and all isolates (1a, 1–13) were evaluated for their cytotoxicities using two human cancer cell lines.     

Diarylheptanoids from the rhizomes of Alpinia officinarum and their anticancer activity

Two new diarylheptanoids (1, 2), together with two known analogs (3, 4), were isolated from the rhizomes of Alpinia officinarum. The new compounds were elucidated to be (5S)-5-hydroxy-7-(3, 4-dihydroxyphenyl)-1-phenyl-3-heptanone (1) and (5R)-5-hydroxy-7-(3-methoxy-4, 5-dihydroxyphenyl)-1-phenyl-3-heptanone (2) based on their spectral analysis. Compound 4 showed moderate cytotoxicity against human tumor cell lines, HepG2, MCF-7 and SF-268, while no significant effect were found for compounds 1-3.     

2-aryl benzofurans and their derivatives from seeds of Styrax macranthus

Two new 2-aryl benzofuran derivatives, 3-[7-methoxy-2-(3,4-methylenedioxyphenyl) benzofuran-5-yl]propyl 3-[7-methoxy-2-(3,4-methylenedioxyphenyl)benzofuran-5-yl]propanoate (1) and demethoxy egonol gentiobioside (2), were isolated from the aqueous ethanolic extract of the seeds of Styrax macranthus, together with 7-methoxy-2-(3,4-methylenedioxyphenyl)benzofuran-5-carbaldehyde, egonol, demethoxy egonol, demethyl egonol, egonol glucoside, egonol gentiobioside, egonol gentiotrioside, stigmasterol, 2,3-dihydroxypropyl tetracosoate, and daucosterol. Their structures were elucidated on the basis of spectral and chemical evidence.     

Response of bark beetles and their natural enemies to fire and fire surrogate treatments in mixed-conifer forests in western Montana

Four treatments (control, burn-only, thin-only, and thin-and-burn) were evaluated for their effects on bark beetle-caused mortality in both the short-term (one to four years) and the long-term (seven years) in mixed-conifer forests in western Montana, USA. In addition to assessing bark beetle responses to these treatments, we also measured natural enemy landing rates and resin flow of ponderosa pine (Pinus ponderosa) the season fire treatments were implemented. All bark beetles were present at low population levels (non-outbreak) for the duration of the study. Post-treatment mortality of trees due to bark beetles was lowest in the thin-only and control units and highest in the units receiving burns. Three tree-killing bark beetle species responded positively to fire treatments: Douglas-fir beetle (Dendroctonus pseudotsugae), pine engraver (Ips pini), and western pine beetle (Dendroctonus brevicomis). Red turpentine beetle (Dendroctonus valens) responded positively to fire treatments, but never caused mortality. Three fire damage variables tested (height of crown scorch, percent circumference of the tree bole scorched, or degree of ground char) were significant factors in predicting beetle attack on trees. Douglas-fir beetle and pine engraver responded rapidly to increased availability of resources (fire-damaged trees); however, successful attacks dropped rapidly once these resources were depleted. Movement to green trees by pine engraver was not observed in plots receiving fire treatments, or in thinned plots where slash supported substantial reproduction by this beetle. The fourth tree-killing beetle present at the site, the mountain pine beetle, did not exhibit responses to any treatment. Natural enemies generally arrived at trees the same time as host bark beetles. However, the landing rates of only one, Medetera spp., was affected by treatment. This predator responded positively to thinning treatments. This insect was present in very high numbers indicating a regulatory effect on beetles, at least in the short-term, in thinned stands. Resin flow decreased from June to August. However, resin flow was significantly higher in trees in August than in June in fire treatments. Increased flow in burned trees later in the season did not affect beetle attack success. Overall, responses by beetles to treatments were short-term and limited to fire-damaged trees. Expansions into green trees did not occur. This lack of spread was likely due to a combination of high tree vigor in residual stands and low background populations of bark beetles.     

Four new sesquiterpenes from Commiphora myrrha and their neuroprotective effects

Four new sesquiterpenes, myrrhterpenoids K-N (1-4) have been isolated from the resin of Commiphora myrrha. Their structures and relative configurations were elucidated by spectroscopic methods (IR, ESIMS, HR-ESIMS, 1D and 2D NMR). Compounds 1 and 4 showed neuroprotective effects against MPP(+)-induced neuronal cell death in SH-SY5Y cells.     

Sesquiterpenoids from Carpesium divaricatum and their cytotoxic activity

In the course of searching for cytotoxic terpenoids from medicinal plants in China, two new eudesmane sesquiterpenoids, 5α-hydroxy-13-methoxy-7αH,11αH-eudesm-4(15)-en-12,8β-lactone (1) and 1β-hydroxy-7αH,11αH-eudesm-4(15)-en-12,8β-lactone (2), along with fourteen known sesquiterpenoids were isolated from the whole plant of Carpesium divaricatum. The structures of new compounds were determined using spectroscopic methods, including IR, HRESIMS, and 1D and 2D NMR spectroscopy. The cytotoxicity of selected sesquiterpene lactones against human oral epidermoid carcinoma (KB), human breast cancer (MCF-7) and human hepatoma (HepG-2) cells was also evaluated by MTT method.     

Nepetalactone content in shoot cultures of three endemic Nepeta species and the evaluation of their antimicrobial activity

Rapid micropropagation of Nepeta rtanjensis, N. sibirica and N. nervosa was performed. Qualitative and quantitative nepetalactone content in methanol extracts of in vitro grown plants was analysed by reverse-phase HPLC coupled with UV and MS detection. Only trans,cis-nepetalactone was detected in shoots of N. rtanjensis, while cis,trans-nepetalactone stereoisomer was present in N. sibirica. No nepetalactone was observed in shoots of N. nervosa. The antimicrobial activity of methanol extracts, against eight bacterial and eight fungal species, was evaluated. All the tested extracts showed significant antibacterial and strong antifungal activity. However, N. rtanjensis extract exhibited the best antimicrobial potential.     

Echinosporins as new cell cycle inhibitors and apoptosis inducers from marine-derived Streptomyces albogriseolus

Bioassay-guided fractionation of the ethyl acetate extract from the fermentation broth of marine-derived Streptomyces albogriseolus A2002 led to the isolation of echinosporin (1) and 7-deoxyechinosporin (2). Compound 1 inhibited the proliferation of tsFT210, K562 and HCT-15 cancer cells (IC(50) 91.5 microM, 25.1 microM and 247 microM respectively) and 2 showed the same effect on K562 cells (IC(50) 143 microM). Flow cytometric analysis suggested that 1 and 2 exert their anti-proliferative effects on those cells through inhibiting cell cycle at the G(2)/M phase and inducing apoptosis.     

Tyrosinase inhibition constituents from the roots of Morus australis

The phytochemical profiles of Morus australis roots, stems and twigs were firstly compared by HPLC analysis. It was found that Morus australis stem extract mainly contained one known tyrosinase inhibitor, oxyresveratrol, while its root and twig extract might contain some unknown potential tyrosinase inhibitors. The root extract of Morus australis was further investigated in this study. One new compound, austraone A, together with 21 known compounds, was isolated and their structures were identified by interpretation of MS and NMR data. In the tyrosinase inhibitory testing, some of them, such as oxyresveratrol, moracenin D, sanggenon T, and kuwanon O, exhibited stronger tyrosinase inhibitory activities than that of kojic acid. These results suggested the Morus australis root extract as a good source of natural tyrosinase inhibitors with a great potential to be used in foods as anti-browning agents and in cosmetics as skin-whitening agents.     

Arthropod repellency, especially tick (Ixodes ricinus), exerted by extract from Artemisia abrotanum and essential oil from flowers of Dianthus caryophyllum

A toluene extract of southernwood (Artemisia abrotanum) and the essential oil from flowers of carnation (Dianthus caryophyllum ) exerted pronounced a repellent effect both against ticks (nymphs of Ixodes ricinus) and yellow fever mosquitoes (Aedes aegypti). The most potent repellents found were coumarin and thujyl alcohol from A. abrotanum and phenylethanol from D. caryophyllum where coumarin and thujyl alcohol were also detected.     

Cassine, an antimicrobial alkaloid from Senna racemosa

The leaves of Senna racemosa yielded the piperidine alkaloid cassine and an inositol methyl ether. Antimicrobial screening of the compounds revealed antibacterial activity of cassine with minimum inhibitory concentrations of 2.5 mg/ml for Staphylococcus aureus and Bacillus subtilis and 5.0 mg/ml for Candida albicans.