HPTLC Quantification and Antimicrobial Activity of Ursolic Acid from Diospyros melanoxylon

JPC – Journal of Planar Chromatography – Modern TLC - An important bioactive molecule, ursolic acid was isolated from the leaves of Diospyros melanoxylon and characterized with help of...     

Flavonol glycosides in leaves of two Diospyros species

Fourteen flavonol glycosides including two new compounds were isolated from the leaves of two Diospyros plants (D. cathayensis and D. rhombifolia). The structures of isolated compounds were determined by spectroscopic analysis. The scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical of the isolated compounds was also investigated.     

Two new compounds from the heartwood of Dalbergia melanoxylon

Abstract

A new neoflavonoid, named S(+)-3′-hydroxy-4′,2,4,5-tetramethoxydalbergiquinol (1), and a new benzofuran, named (2S,3S)-5-hydroxy-6-methoxy-3-methyl-2-(4′-hydroxyphenyl)-2,3dihydrobenzofuran (4), together with two known neoflavonoids, were isolated from the heartwood of Dalbergia melanoxylon. Their structures were elucidated by a combination of spectroscopic methods and comparison with the literature. Compounds 1–4 were evaluated for inhibitory activity against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 6538, Salmonella enteri CMCC 50041 and Candida albicans ATCC 289065, which all exhibited inactive or weak activity.     

Isostreptazolin and sannaphenol, two new metabolites from Streptomyces sannanensis

Two new compounds, isostreptazolin (1) and sannaphenol (2), were isolated from the culture broth of Streptomyces sannanensis and their structures elucidated on the basis of 1D and 2D NMR as well as MS, IR and UV spectroscopic data analysis. The cytotoxic activity of 1 and 2 were evaluated. Both compounds were inactive against H460 and HeLa cell lines at 100 mM.     

Six new compounds from the heartwood of Diospyros maritima

Six new compounds, diospyrolide (1), diospyrolidone (2), diethyl (2R)-malate (3), 3-(E)-coumaroylbetulin-28-yl ethyl nonanedioate (4), 3-(E)-coumaroylbetulin-28-yl ethyl succinate (5), and 3-(E)-coumaroylbetulin-28-yl ethyl (2R)-2-hydroxysuccinate (6), have been isolated from the heartwood of Diospyros maritima. Compounds 1 and 2 are novel trinorlupanes, and 4, 5 and 6 are lupane derivatives. Their structures were determined using spectral and chemical methods.     

A new 18,19-secoursane triterpene from the leaves of <Emphasis Type="Italic">Diospyros kaki</Emphasis>

A new 18,19-secoursane triterpene together with five known compounds were isolated from the leaves of Diospyros kaki. The structure of the new compound was elucidated as 18,19-seco-3β-hydroxy-urs-12-en-18-one on the basis of spectroscopic methods.     

A new triterpene from the leaves ofBetula mandschurica

A new triterpene (I) has been isolated from the unsaponifiable fraction of an ethereal extract of the leaves ofBetula mandschurica to which, on the basis of the results of a physicochemical investigation and a comparison of the¹³C spectra with the spectra of known triterpenes — ocotillone (II) and 20(S)-hydroxydammar-24-en-3-one (III) — the structure of 20(S),24(S)-dihydroxydammar-25-3n-3-one has been assigned. An approach to the determination of the configuration of the asymmetric center at C₂₄ in 24-hydroxy derivatives of tetracyclic triterpenoids with an open side chain by the use of¹³C NMR spectroscopy is proposed.Pacific Ocean Institute of Bioorganic Chemistry of the Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 346–351, May–June, 1980.     

ent-Homoabyssomicins A and B, two new spirotetronate metabolites from Streptomyces sp. Ank 210

ent-Homoabyssomicins A (1) and B (2) are new complex polycyclic spirotetronate metabolites isolated from Streptomyces sp. isolate Ank 210. The structures of 1 and 2 were elucidated by detailed spectroscopic analyses of 1D and 2D NMR data. The absolute configuration of 1 was established by subsequent single-crystal X-ray diffraction studies.     

A novel chlorinated norsesquiterpenoid and two related new metabolites from the soft coral Paralemnalia thyrsoides

A structurally unique chlorinated norsesquiterpenoid, paralemnolin A (1), along with two new metabolites, paralemnolin B (2) and C (3), have been isolated from the soft coral Paralemnalia thyrsoides. Their structures were determined by extensive spectroscopic analyses. Single-crystal X-ray diffraction analysis of 1 further establish the absolute stereochemistry of 1.     

Three new naphthoquinone derivatives from Diospyros maritima Blume

Three new naphthoquinone derivatives, 6-(1-ethoxyethyl)plumbagin (16), ethylidene-3,3'-biplumbagin (17), and ethylidene-3,6'-biplumbagin (18), were isolated, in addition to six known naphthoquinones, isozeylanone (10), 3,3'-biplumbagin (11), chitranone (12), methylene-3,3'-biplumbagin (13), 2,3-epoxyplumbagin (14), and 3,8'-biplumbagin (15), from the fruits of Diospyros maritima Blume (Ebenaceae). The structures of the new compounds were established by spectroscopic methods. The eight naphthoquinones 11-18 were examined for ichthyotoxic activity and germination inhibitory activity. The quinones 11, 12, and 14-16 showed strong ichthyotoxic activity and the quinone 14 mild germination inhibitory activity.     

A new benzodioxocinone from the leaves of Cinnamomum tenuifolium

Investigation of the leaves' extract of Cinnamomum tenuifolium (Lauraceae) led to the isolation of one novel benzodioxocinone, 2,3-dihydro-6,6-dimethylbenzo-[b][1,5]dioxocin-4(6?H)-one (1). The structure was determined through in-depth spectroscopic and mass-spectrometric analyses. The antioxidant potential was evaluated using the following in?vitro method: scavenging of 1,1-diphenyl-2-picrylhydrazyl radical. We also detected the anti-proliferative effect of 1 on human oral cancer cells and its IC(50) is 107.7?μM.     

A new gamma-lactone from the leaves of Cinnamomum kotoense

A new C19 gamma-lactone, cinnakotolactone (1), along with a known analogue, isolinderanolide B (2), were isolated from the n-hexane layer of the leaf extracts of Cinnamomum kotoense. Their structures were elucidated on the basis of spectroscopic analysis. The anti-proliferation activities of 1 and 2 were evaluated against human HT29 and MCF-7 cancer cell lines, and their IC50 values ranged from 3.3 +/- 0.3 to 25.8 +/- 5.3 microM.     

A new glycoside from the leaves of Neoalsomitra integrifoliola

A new ionone glycoside （6R,9R）-blumenyl α-L-rhamnopyranosyl-（1 → 6）-β-D-gluco-pyranoside （1）, together with a new natural product 2-methoxyl-4-trans-pmpenyl-phenol α-L-rhamnopyranosyl-（1 → 6）-β-D-glucopyranoside （2）, was isolated from the leaves ofNeoalsomitra integrifoliola. Their structures were elucidated by chemical and spectral analysis. Compound 1 showed weak anti-inflammatory and low-level antioxidant activities.     

A new norisoprenoid from the leaves of Ficus pumila

One new norisoprenoid 3,9-dihydroxy dihydro actinidiolide (1), together with eleven known compounds (2–12), were isolated from ethanol extract of the leaves of Ficus pumila collected in Hainan Province, China. Their structures were elucidated by the detailed analysis of comprehensive spectroscopic data. Compounds 1, 2, 4, 5, 8 and 10–12 were isolated from the F. pumila for the first time. All compounds were evaluated for their cytotoxic activity. Compounds 3 and 9 showed weak cytotoxic activity against Hela, MCF-7 and A549 cell lines.     

A new triterpene from the leaves of Craibiodendron yunnanense

A new triterpene, taraxast-20(30)-en-3β,12β-diol (1), and eight known compounds were isolated from the leaves of Craibiodendron yunnanense. Their structures were established on the basis of spectral evidence. Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 35–37, January–February, 2008.     

A gas chromatographic determination of residues of eleven insecticides and two metabolites on olive tree leaves

A gas chromatographic (GC) method was developed and statistically validated for the simultaneous determination of residues of pyrethroid, endosulfan, and organophosphorus insecticides and some of their metabolites on olive tree leaves. Pesticide residues were extracted by static extraction with acetone-dichloromethane. After evaporation of the extract to dryness and redissolution in acetone, the organophosphorus insecticides were determined by GC with nitrogen-phosphorus detection. Another portion of the extract, after solvent change to acetonitrile, was cleaned up on an Alumina-N cartridge and analyzed for insecticides sensitive to electron-capture detection (ECD), i.e., pyrethroids and endosulfan and its metabolite. Recoveries of the organophosphorus insecticides ranged from 80.7 to 93.3% with relative standard deviations (RSDs) of < or = 7.2%; recoveries of the ECD-sensitive insecticides ranged from 71.6 to 89.5% with RSDs of < or = 11.6%. The method was used to analyze 26 samples of olive tree leaves from organic olive groves all over Greece, and the results confirmed the viability of the method for routine analysis. Residues of fenthion and fenthion sulfoxide were found in one and 3 samples, respectively, and their identities were confirmed by GC with mass spectrometry.     

A new steroid saponin from the leaves ofYucca aloifolia

A new steroid saponin has been isolated from the air-dry leaves ofYucca aloifolia L., and it has been shown to be (25R)-5β-spirostan-3β-ol O-D-glucopyranosyl-(1 → 2)-D-galactopyranoside. The substance melts at 302–303°C [α]D²⁰ ?27.2, (c 1.0; CHCl₃).     

Isolation and structure elucidation of two new cytotoxic metabolites from red yeast rice

In this study, 10 already described secondary metabolites and 2 unknown metabolites were identified in an extract of Monascus purpureus by high-performance liquid chromatography-diode array detection. The unknown metabolites were isolated and their chemical structures were elucidated. The new metabolites possess the molecular formulas C(21)H(27)NO(4) and C(23)H(31)NO(4). They were named monascopyridines E and F due to their pyridine backbone. The cytotoxicity of the new compounds was studied using immortalised human kidney epithelial cells displaying IC(50) values in the micromolar range.