A New Depsidone from Teloschistes flavicans and the Antileukemic Activity.

Lichens produce a variety of secondary metabolites that could be potential sources of pharmaceutically useful chemicals. However, only a limited number of lichen metabolites have been investigated for their biological significance. The objective of this study was to identify the potential compounds responsible for the antileukemic activity of lichen Teloschistes flavicans. Among three fractions (n-hexane, EtOAc, and MeOH-H2O), the ethyl acetate (EtOAc) fraction of T. flavicans methanolic extract showed the strongest inhibition in the HL-60 cell line. Additionally, the EtOAc fraction was further purified to obtain a new depsidone, 2,7-dichloro-3,8-dimethoxy-1,6,9-trimethyl-11H-dibenzo[b,e][1,4]dioxepin-11-one, named as flavicansone, along with rhizonic acid, parietin, and vicanicin. Flavicansone demonstrated the most significant inhibitory action against cell proliferation among the four isolated compounds.

A SEM study of unexplored wax microtubes produced by caterpillar living on common banana leaves.

The primary concern of this research is to perform a microscopic analysis of the natural wax covering banana skipper caterpillar. The scanning electron microscopic (SEM) analysis shows that the wax exhibits an unprecedented microtubular form, consisting of carbon and oxygen as main elements as revealed by energy dispersive X-ray (EDX) analysis. The Fourier Transform Infra-Red (FTIR) spectroscopic analysis, which reveals the presence of peaks at 2914, 2890, 1469, and 722 cm-1 and the absence of peaks around 1700 cm-1, indicates that the analyzed natural wax is a polyethylene wax without the CO functional group.

Chemical Constituents of Coreopsis lanceolata Stems and Their Antitermitic Activity Against the Subterranean Termite Coptotermes curvignathus.

Coreopsis lanceolata is an Asteraceous plant known to contain semiochemicals active against nematodes and leukemic agents. The objective of the study was to discover termite resistant constituents from C. lanceolata stems. Five compounds were isolated from C. lanceolata stems. These compounds were identified as 5-phenyl-2-(1-propynyl)-thiophene (1), 1-phenylhepta-1,3,5-tryne (2), ß-sitosterol (3), succinic acid (4), and protocatechuic acid (5), respectively; they were confirmed by spectroscopic analysis. Their antitermitic effects were evaluated with the no-choice feeding test against Coptotermes curvignathus. Of the isolates, 5-phenyl-2-(1-propynyl)-thiophene (1) and 1-phenylhepta-1,3,5-tryne (2) showed strong potent antitermitic activity. Our findings suggested that compounds 1 and 2 isolated from C. lanceolata stems appears to be the active ingredients.

Antileukemic activity of lignans and phenylpropanoids of Cinnamomum parthenoxylon.

In this study, we evaluated the in vitro cytotoxicity of fractions and isolated constituents from Cinnamomum parthenoxylon woods against human leukemia HL-60 and U937 cells. The n-Hex, EtOAc, and MeOH-H2O fractions of the woods inhibited cell proliferation in both cell lines. Our phytochemical investigation of the n-Hex and EtOAc fractions led to the isolation of lignans and phenylpropanoids, whose chemical structures were confirmed by spectroscopic analyses. All isolated compounds were evaluated for their in vitro antileukemic activity; especially, hinokinin and cubebin exhibited strong inhibition toward U937 cell proliferation. Morphological observation indicated that these cytotoxic actions were mediated by apoptosis. Our findings suggested that an oxygenated functional group at the C-9 position in dibenzylfuran skeleton contributed their potency. In addition, these results enhanced the ethnopharmacological value of C. parthenoxylon.

Phytochemical analysis and antileukemic activity of polyphenolic constituents of Toona sinensis.

Toona sinensis is a traditional Chinese medicine belonging to the Meliaceae family. The aim of this study was to identify the potential compounds responsible for anticancer activity of T. sinensis. The EtOAc extracts of leaves and woods of T. sinensis inhibited cell proliferation and induced apoptosis in human leukemia HL-60 cells. Our phytochemical research of these extracts led to the isolation of various polyphenolic constituents. The chemical structures were determined by spectroscopic analyses. Among isolates, gallic acid and loropetalin D showed inhibition of cell proliferation and possible induction of apoptosis in these cells. Overall, our results revealed the importance of T. sinensis as a chemopreventive medicinal plant. In addition, an analysis of structure-activity relationship indicated that the number of galloyl groups affects their antileukemic potency.

Chemical constituents of Indonesian plant Protium javanicum Burm. f. and their antifeedant activities against Coptotermes formosanus Shiraki.

In the continuing study of antifeedant compounds in Protium javanicum Burm. f. against Coptotermes formosanus Shiraki, 6-desacetylnimbin (1), quercitrin (2) and myricitrin (3) were isolated from P. javanicum extract. All compounds were characterised by NMR and MS. Furthermore, the structure of 6-desacetylnimbin was confirmed by X-ray crystallography. The antifeedant activity was evaluated with no-choice feeding tests. At a dose of 0.5 mg, 6-desacetylnimbin exhibited the highest antifeedant activity among the isolates.

Inhibitory effects of 6-alkoxycoumarin and 7-alkoxycoumarin derivatives on lipopolysaccharide/interferon γ-stimulated nitric oxide production in RAW264 cells.

Coumarin and its derivatives are well known for their anti-inflammatory and anti-oxidative effects. In this study, we synthesized 32 coumarin derivatives from commercially available 6-hydroxycoumarin (6HC) and 7-hydroxycoumarin (7HC) and examined their effects on lipopolysaccharide/interferon γ (LPS/IFNγ)-stimulated nitric oxide (NO) production in murine macrophage RAW264 cells. Among these derivatives, 6HC-8 (6-(3-phenylpropoxy)coumarin), 6HC-14 (6-(2-octynyloxy)coumarin), 7HC-14 (7-(2-octynyloxy)coumarin), and 7HC-16 (7-(3,5-dimethoxybenzyloxy)coumarin) markedly suppressed NO production at low concentration (25 µM). These synthesized coumarin derivatives also markedly inhibited inducible NO synthase (iNOS) protein and mRNA expression, as assessed by western blotting and quantitative real time-polymerase chain reaction (RT-PCR).

Antifeedant and termiticidal activities of 6-alkoxycoumarins and related analogs against Coptotermes formosanus Shiraki.

We synthesized 23 6-alkoxycoumarin derivatives, 20 of which are novel compounds. The structures of all compounds were confirmed by NMR, MS, and elemental analysis, and their antifeedant and termiticidal activities against Coptotermes formosanus Shiraki were examined. In a no-choice test, 6-(2-pentynyloxy)coumarin (2v), 6-(2-butynyloxy)coumarin (2u), 6-(2-octynyloxy)coumarin (2w), and 6-methoxycoumarin (2a), demonstrated high termiticidal activity at a concentration of 10 µmol. At a concentration of 5 µmol, 6-(2-butynyloxy)coumarin (2u) produced the highest mortality among the compounds tested. On the other hand, all of the 6-alkoxycoumarins showed antifeedant activity at both concentrations, except 6-octadecyloxycoumarin (2j) that was inactive at 5 µmol. Among the 23 compounds and the control, 6-ethoxycoumarin (2b), 6-isopropoxycoumarin (2d), and 6-isobutoxycoumarin (2f) exhibited the highest antifeedant activity with no mass loss (0.00%) at a concentration of 10 µmol. Our findings indicate that the presence of alkenyloxy and alkynyloxy groups was important for the termiticidal activity, while the incorporation of alkoxy groups with longer alkyl chains tended to reduce both the termiticidal and antifeedant activities. Furthermore, short chain alkoxy and arylalkoxy-substituted analogs showed good antifeedant activity, but methoxy groups on the benzene ring had a negative effect.

Antitermite activities of coumarin derivatives and scopoletin from Protium javanicum Burm. f.

The antitermite (termiticidal and antifeedant) activity of Protium javanicum Burm. f. extract was investigated. The ethyl acetate fraction was active. Scopoletin (1), quercetin, and stigmasterol were isolated by bioassay-guided fractionation. Scopoletin had the highest activity among the three compounds. In order to investigate the structure-activity relationship (SAR) of the methoxy and hydroxy groups at the C-6 and C-7 positions of the coumarin skeleton, we synthesized several coumarin derivatives whose chemical structures are similar to scopoletin. Scopoletin exhibited the strongest termiticidal activity among the 10 compounds tested, followed by 6-methoxycoumarin (3), 6-hydroxycoumarin (7), and umbelliferone (8). All compounds except coumarin (9) showed antifeedant activity.

6-Benzyl-oxycoumarin.

In the title compound, 6-benz-yloxy-2H-1-benzopyran-2-one, C(16)H(12)O(3), the coumarin unit and benzyl plane in the mol-ecule are perpendicular to each other [86.92 (7)°]. The crystal packing is stabilized by π-π stacking inter-actions, with an inter-planar separation between inversion-related coumarin units of 3.618 (3) Å. The crystal structure shows inter-molecular C-H⋯O hydrogen bonding between neighboring mol-ecules.