A sesquiterpenoid tropolone and 1,2,3,4-tetrahydronaphthalene derivatives from Olax imbricata roots.

The methanol extract of Olax imbricata roots afforded one new sesquiterpenoid tropolone and three new 1,2,3,4-tetrahydronaphthalene derivatives, olaximbrisides A-D (1-4). Their structures were determined by 1D and 2D NMR experiments in combination of HRESIMS. The relative configurations were assigned by the NOESY experiments. The absolute configurations were established by a combination of X-ray diffraction analysis and electronic circular dichroism (ECD) experiments. All isolated compounds were evaluated for their cytotoxic effects against some cancer cell lines. Among them, compound 1 exhibited the cytotoxicities against MCF-7, HepG2 and LU cell lines with IC50 values of 16.3, 34.3 and 8.0 µM, respectively.

New Bis-Alkenoic Acid Derivatives from a Marine-Derived Fungus Fusarium solani H915.

Fusarium solani H915 is a fungus derived from mangrove sediments. From its ethyl acetate extract, a new alkenoic acid, fusaridioic acid A (1), three new bis-alkenoic acid esters, namely, fusariumester A1 (2), A2 (3) and B (4), together with three known compounds (5⁻7), were isolated. The structures of the new compounds were comprehensively characterized by high resolution electrospray ionization-mass spectrometry (HR-ESI-MS), 1D and 2D nuclear magnetic resonance (NMR). Additionally, the antifungal activities against tea pathogenic fungi Pestalotiopsis theae and Colletotrichum gloeosporioides were studied. The new compound, 4, containing a ß-lactone ring, exhibited moderate inhibitory activity against P. theae, with an MIC of 50 µg/disc. Hymeglusin (6), a typical ß-lactone antibiotic and a terpenoid alkaloid, equisetin (7), exhibited potent inhibitory activities against both fungal species. The isolated compounds were evaluated for their effects on zebrafish embryo development. Equisetin clearly imparted toxic effect on zebrafish even at low concentrations. However, none of the alkenoic acid derivatives exhibited significant toxicity to zebrafish eggs, embryos, or larvae. Thus, the ß-lactone containing alkenoic acid derivatives from F. solani H915 are low in toxicity and are potent antifungal agents against tea pathogenic fungi.

Equisetin as potential quorum sensing inhibitor of Pseudomonas aeruginosa.

OBJECTIVE: To screen for the quorum-sensing (QS) inhibitors from marine-derived fungi and evaluate their anti-QS properties in Pseudomonas aeruginosa. RESULTS: QS inhibitory activity was found in secondary metabolites of a marine fungus Fusarium sp. Z10 using P. aeruginosa QSIS-lasI biosensor. The major active compound of this fungus was isolated by HPLC and identified as equisetin. Subinhibitory concentration of equisetin could inhibit the formation of biofilm, swarming motility, and the production of virulence factors in P. aeruginosa. The inhibition of las, PQS, and rhl system by equisetin were determined using Escherichia coli MG4/pKDT17, E.coli pEAL08-2, and E.coli pDSY, respectively. Real-time RT-PCR assays showed that equisetin could downregulate the mRNA expression of QS-related genes. CONCLUSIONS: Equisetin proved its potential as an inhibitor against P. aeruginosa QS system and might also serve as precursor compound in development of novel therapeutics for infectious diseases by optimal design of structures.

Camphor sulphonic acid mediated quantitative 1,3-diol protection of major Labdane diterpenes isolated from Andrographis paniculata.

Phytochemical survey of the methanol extract of the dried aerial parts of Andrographis paniculata led to the isolation of major labdane diterpenes, namely 14-deoxy-11,12-didehydroandrographolide, andrographolide and neoandrographolide. Andrographolide was found to be the major phytoconstituent of the plant which was biologically active. For better physiochemical characteristics and bioefficacy, andrographolide is subjected to semi-synthetic modifications. However, presence of several free hydroxyl groups associated with this molecule make it quite polar and poorly soluble in many organic solvents and hence unsuitable for synthetic modifications. One way of resolving its solubility issue is to protect 1,3-diol quantitatively under mild reaction condition without effecting other functional groups. Reaction conditions were optimised using different solvent systems and catalysts towards this direction. X-ray structure of 3,19-isopropylidene-14-deoxy-11,12-didehydroandrographolide is being reported here for the first time. Isolated compounds and derivatives were confirmed by spectral analysis or X-ray data analysis.

Antimicrobial activities of endophytic fungi obtained from the arid zone invasive plant Opuntia dillenii and the isolation of equisetin, from endophytic Fusarium sp.

BACKGROUND: Opuntia dillenii is an invasive plant well established in the harsh South-Eastern arid zone of Sri Lanka. Evidence suggests it is likely that the endophytic fungal populations of O. dillenii assist the host in overcoming biotic and abiotic stress by producing biologically active metabolites. With this in mind there is potential to discover novel natural products with useful biological activities from this hitherto poorly investigated source. Consequently, an investigation of the antimicrobial activities of the endophytes of O. dillenii, that occupies a unique ecological niche, may well provide useful leads in the discovery of new pharmaceuticals. METHODS: Endophytic fungi were isolated from the surface sterilized cladodes and flowers of O. dillenii using several nutrient media and the antimicrobial activities were evaluated against three Gram-positive and two Gram-negative bacteria and Candida albicans. The two most bioactive fungi were identified by colony morphology and DNA sequencing. The secondary metabolite of the endophyte Fusarium sp. exhibiting the best activity was isolated via bioassay guided chromatography. The chemical structure was elucidated from the ESIMS and NMR spectroscopic data obtained for the active metabolite. The minimum inhibitory concentrations (MICs) of the active compound were determined. RESULTS: Eight endophytic fungi were isolated from O. dillenii and all except one showed antibacterial activities against at least one of the test bacteria. All extracts were inactive against C. albicans. The most bioactive fungus was identified as Fusarium sp. and the second most active as Aspergillus niger. The structure of the major antibacterial compound of the Fusarium sp. was shown to be the tetramic acid derivative, equisetin. The MIC's for equisetin were 8 µg mL(-1) against Bacillus subtilis, 16 µg mL(-1) against Staphylococcus aureus and Methicillin Resistant Staphylococcus aureus (MRSA). CONCLUSIONS: O. dillenii, harbors several endophytic fungi capable of producing antimicrobial substances with selective antibacterial properties. By producing biologically active secondary metabolites, such as equisetin isolated from the endophytic Fusarium sp., the endophytic fungal population may be assisting the host to successfully withstand stressful environmental conditions. Further investigations on the secondary metabolites produced by these endophytes may provide additional drug leads.

Isolation and biological activity of a novel cadinane-type sesquiterpenoid from the essential oil of Alangium salviifolium.

The components of the essential oil from the roots of Alangium salviifolium were analyzed by capillary gas chromatography-mass spectrometry (GC-MS). Ninety compounds, representing 74.5% of the total oil, were identified; the main components of the oil were epi-α-cadinol, followed by trans-2-hydroxycalamenene, cadalene, and cadina-4,10(15)-dien-3-one. A further unknown component comprised 5.5% of the oil. Therefore, the essential oil was purified by flash column chromatography to isolate this component. Its structure was established using extensive spectroscopic data analyses, including NMR, HR-EI-MS, and IR. The results showed that this isolated compound was (-)-7, 8-dihydroxycalamenal, which is a novel cadinane-type sesquiterpenoid. This compound was tested for its antioxidant activity and inhibition of tyrosinase, and showed particularly strong inhibition effects.

Cytotoxic aryltetralin lignans from fruits of Cleistanthus indochinensis.

Eight new aryltetralin lignans, cleisindosides A-F (1-6), picroburseranin (7), and 7-hydroxypicropolygamain (8), were isolated from the fruits of Cleistanthus indochinensis (Euphorbiaceae). The structures of the isolates were established on the basis of their one- and two-dimensional NMR spectral data, as well as their mass spectrometric data. Compound 7 was found to have potent cytotoxicity against oral epidermoid carcinoma cells with an IC50 value of 0.062 µM, whereas glycosylation to 3 (IC50 7.5 µM) and stereochemical changes to 8 (IC50 10.8 µM) led to marked decreases in biological activity. Thus, it was determined that the C-7 and C-8' positions are critical for the biological activity of the lignans from this plant.

Extraction of three bioactive diterpenoids from Andrographis paniculata: effect of the extraction techniques on extract composition and quantification of three andrographolides using high-performance liquid chromatography.

Andrographis paniculata (Burm.f.) wall.ex Nees (Acanthaceae) or Kalmegh is an important medicinal plant finding uses in many Ayurvedic formulations. Diterpenoid compounds andrographolides (APs) are the main bioactive phytochemicals present in leaves and herbage of A. paniculata. The efficiency of supercritical fluid extraction (SFE) using carbon dioxide was compared with the solid-liquid extraction techniques such as solvent extraction, ultrasound-assisted solvent extraction and microwave-assisted solvent extraction with methanol, water and methanol-water as solvents. Also a rapid and validated reverse-phase high-performance liquid chromatography-diode array detection method was developed for the simultaneous determination of the three biologically active compounds, AP, neoandrographolide and andrograpanin, in the extracts of A. paniculata. Under the best SFE conditions tested for diterpenoids, which involved extraction at 60°C and 100 bar, the extractive efficiencies were 132 and 22 µg/g for AP and neoandrographolide, respectively. The modifier percentage significantly affected the extraction efficiency.

Qualitative and quantitative analysis of Andrographis paniculata by rapid resolution liquid chromatography/time-of-flight mass spectrometry.

A rapid resolution liquid chromatography/time-of-flight tandem mass spectrometry (RRLC-TOF/MS) method was developed for qualitative and quantitative analysis of the major chemical constituents in Andrographis paniculata. Fifteen compounds, including flavonoids and diterpenoid lactones, were unambiguously or tentatively identified in 10 min by comparing their retention times and accurate masses with standards or literature data. The characteristic fragmentation patterns of flavonoids and diterpenoid lactones were summarized, and the structures of the unknown compounds were predicted. Andrographolide, dehydroandrographolide and neoandrographolide were further quantified as marker substances. It was found that the calibration curves for all analytes showed good linearity (R² > 0.9995) within the test ranges. The overall limits of detection (LODs) and limits of quantification (LOQs) were 0.02 µg/mL to 0.06 µg/mL and 0.06 µg/mL to 0.2 µg/mL, respectively. The relative standard deviations (RSDs) for intra- and inter-day precisions were below 3.3% and 4.2%, respectively. The mean recovery rates ranged from 96.7% to 104.5% with the relative standard deviations (RSDs) less than 2.72%. It is concluded that RRLC-TOF/MS is powerful and practical in qualitative and quantitative analysis of complex plant samples due to time savings, sensitivity, precision, accuracy and lowering solvent consumption.

[Advances in studies on aryltetralin lactone lignans].

Natural aryltetralin lactone lignans existed in the plants of family Berberidaceae, Acanthaceae, Burseraceae, Verbenaceae, Euphorbiaceae, etc. Due to the antineoplastic and antiviral properties, it has become a hot research topic in medicinal chemistry. This review covers extraction and isolation, biosynthesis, plant origin, and structure and spectral characteristics of natural aryltetralin lactone lignans. It will provide a useful reference for the intensive studies and rational utilization of aryltetralin lactone lignans.

Two novel phenolic compounds from the rhizomes of Cyperus rotundus L.

Two novel compounds, 1α-methoxy-3ß-hydroxy-4α-(3',4'-dihydroxyphenyl)-1, 2,3,4-tetrahydronaphthalin (1) and 1α,3ß-dihydroxy-4α-(3',4'-dihydroxyphenyl)-1,2,3,4-tetrahydronaphthalin (2), were isolated along with six known compounds 3-8 from the rhizomes of Cyperus rotundus. This paper reports the isolation and full spectroscopic characterization of these new compounds by NMR, UV, IR and MS data.

Anti-mycobacterial natural products from the Canadian medicinal plant Juniperus communis.

ETHNOPHARMACOLOGICAL RELEVANCE: Common juniper, Juniperus communis, is amongst the plants most frequently used by the indigenous peoples of North America for medicinal purposes. The First Nations of the Canadian Maritimes use infusions of juniper primarily as a tonic and for the treatment of tuberculosis. Previous investigations of extracts derived from the aerial parts of J. communis have shown it to possess anti-mycobacterial activity. The aim of the study is to isolate and identify anti-mycobacterial constituents from the aerial parts of J. communis. MATERIALS AND METHODS: Methanolic extracts of J. communis needles and branches were subjected to bioassay guided fractionation using the microplate resazurin assay (MRA) to assess inhibitory activity against Mycobacterium tuberculosis strain H37Ra. The anti-mycobacterial constituents were identified by NMR, MS and polarimetry. RESULTS: The diterpenes isocupressic acid and communic acid and the aryltetralin lignan deoxypodophyllotoxin were isolated from the J. communis extract. Isocupressic acid and communic acid (isolated as an inseparable 3:2 mixture of cis and trans isomers) displayed MICs of 78 µM and 31 µM and IC(50)s of 46 µM and 15 µM against M. tuberculosis H37Ra respectively. Deoxypodophyllotoxin was less active, with a MIC of 1004 µM and an IC(50) of 287 µM. CONCLUSIONS: Isocupressic acid, communic acid and deoxypodophyllotoxin were identified as the principal constituents responsible for the anti-mycobacterial activity of the aerial parts of J. communis. Although further research will be required to evaluate the relative activities of the two communic acid isomers, this work validates an ethnopharmacological use of this plant by Canadian First Nations and Native American communities.

[Study on chemical constituents of Drosera peltata var. multisepala].

Chemical investigatation of Drosera peltata var. multisepala led to the isolation of eleven compounds using various chromatographic techniques. The structures of these compounds were elucidated as isoshinanolone-4-O-beta-D-glucoside (1), isoshinanolone (2), epi-isoshinanolone (3), plumbagin (4), droserone (5), droserone-5-O-glucoside (6), quercetin (7), kaempferol (8) , gossypetin-8-O-glucoside (9), 3,3'-dimethoxy ellagic acid (10), and ellagic acid (11) by their physicochemical properties and spectral data analysis. Compound 1 was a new compound. Compounds 3, 8, 10, and 11 were isolated from this plant for the first time.

[Study on chemical constituents from petroleum ether-soluble parts of cones of Platycladus orientalis].

OBJECTIVE: To study chemical constituents from petroleum ether-soluble parts of cones of Platycladus orientalis. METHODS: The compound were isolaeed by repeated column chromatography of silica gel and Sephadex LH-20. The structures were elucidated by physicochemical properties and spectrum analysis. RESULTS: Seven constituents were isolated and identified as sandaracopimaric acid (1), 6alpha-hydroxy sandaracopimaric acid (2), ent-isopimara-8 (14), 15-dien-3beta, 19-diol (3), ent-isopimara-8 (9), 15-dien-3beta-ol (4), ent-isopimara-8 (14),15- dien-3beta-ol (5), isocupressic acid (6) and 15-acetylisocupressic acid (7). CONCLUSION: Compounds 2 and 7 are isolated from this genus for the first time.

Antimicrobial activities of neo- and 1-epineo-isoshinanolones from Plumbago zeylanica roots.

CONTEXT: The roots of Plumbago zeylanica Linn. (Plumbaginaceae) are reputed to have a wide spectrum of therapeutic properties in the Ayurvedic system of medicine. They are useful in curing many ailments such as skin diseases, diarrhea, plague and leprosy. OBJECTIVE: The study was aimed at isolating, separating and evaluating the antimicrobial properties of compounds such as neoisoshinanolone and 1-epineo-isoshinanolone from the roots of P. zeylanica. MATERIALS AND METHODS: The crude petroleum ether extract of roots of P. zeylanica was subjected to repeated chromatographic techniques to separate compounds 2 and 3 along with plumbagin. Structure elucidation was carried out using nuclear magnetic resonance (NMR), infra red (IR) and mass spectroscopy. The serial dilution method was used to test antimicrobial activities and their minimum inhibitory concentration (MIC) expressed in microg/mL. RESULTS: 1-Epineo-isoshinanolone is more active with a MIC of 12.5-25 microg/mL whereas neoisoshinanolone has recorded a MIC of 50-100 microg/mL. The activities are compared with plumbagin (0.78-3.13 microg/mL) and standards streptomycin for bacteria and nystatin for fungi. DISCUSSION: Earlier researchers have established the presence of plumbagin in the roots of P. zeylanica and its antimicrobial activities. The structure elucidation of two more biologically active biogenetic precursors along with their activities in the root extracts has been established for the first time in the present study. CONCLUSION: The root extract of P. zeylanica possesses good antimicrobial activity, which suggests its therapeutic use in the Ayurvedic system of medicine to cure skin diseases.

Antimicrobial activity of confertifolin from Polygonum hydropiper.

Confertifolin (6,6,9a-trimethyl-4,5,5a,6,7,8,9,9a-octahydronaphtho[1,2-c] furan-3 (1H)-one) was isolated from the essential oil of Polygonum hydropiper L. (Polygonaceae) leaves using column chromatography. Confertifolin showed activity both in bacteria and fungi. The lowest MIC for bacteria was observed against Enterococcus faecalis (31.25 microg/mL). Significant MIC for fungi was observed against Scopulariopsis sp (7.81 microg/mL), Curvularia lunata (7.81 microg/mL), Epidermophyton floccosum (7.81 microg/mL), Trichophyton mentagrophytes (16.62 microg/mL), Trichophyton rubrum (MTCC 296) (16.62 microg/mL), Aspergillus niger (31.25 microg/mL), Botrytis cinerea (31.25 microg/mL) Magnaporthe grisea (62.5 microg/mL), Trichophyton simii (125 microg/mL) and Trichophyton rubrum (clinical isolate) (125 microg/mL).

Neoandrographolide from Andrographis paniculata as a potential natural chemosensitizer.

Extracts of the traditional medicinal herb Andrographis paniculata and its main constituents are described in the literature as showing anticancer activity. The aim of this study was to isolate the main constituents of a commercially available phytotherapeutic preparation of A. paniculata and to determine their chemosensitizing potential in a leukemia cell line. Chromatographic separation steps resulted in the isolation of the diterpenes andrographolide (1) and 14-deoxy-11,12-didehydroandrographolide (3) and the diterpene glucoside neoandrographolide (2). The combination of these constituents with suboptimal concentrations of etoposide revealed compound 2 as chemosensitizer in S-Jurkat and X chromosome-linked inhibitor of apoptosis protein (XIAP)-overexpressing Jurkat cells, a model for chemoresistance.

[Chemical constituents from aerial parts of Plumbago zeylanica Linn].

OBJECTIVE: To investigate the chemical constituents of the aerial parts of Plumbago zeylanica Linn. METHODS: The constituents of the EtOAc-soluble portion in the 95% ethanol extract were isolated and purified by means of chromatography. Compounds were identified by their physical characteristics and spectral features. RESULTS: Nine compounds were isolated as plumbagin (I), isoshinanolone (II), plumbagic acid (III), beta-sitosterol (IV), 4-hydroxybenzaldehyde (V), trans-cinnamic acid (VI), vanillic acid (VII), 2, 5-dimethyl-7-hydroxychromone (VIII), indole-3-carboxaldehyde (IX). CONCLUSION: Compounds V, VII, VIII and IX were isolated for the first time from Plumbago Linn.

[Studies on diterpenoids from Andrographis paniculata].

OBJECTIVE: To study the diterpenoids in the 85% ethanol extract of the aerial parts of Andrographis paniculata. METHOD: Fourteen diterpenoids from the 85% EtOH extract were isolated by the silica gel, Sephadex LH-20, ODS column chromatography and HPLC, and their structures were identified by the spectal analyses and chemical evidences. RESULT: The 14 compounds were obtained and identified as neoandrographolide (1), 3, 14-di-deoxyandrographolide (2), andrographolide (3), 14-deoxy-11, 12-didehydroandrographolide (4), 19-hydroxy-8 (17), 13-labdadien-15, 16-olide (5), 14-deoxy-andrographolide (6), 3-oxo-14-deoxy-andrographolide (7), isoandrographolide, (8), bisandrographolide (9, 10, 11), deoxyandrographiside (12), 14-deoxy-11, 12-didehydroandrographiside (13), andrographiside (14), respectively. CONCLUSION: Compound 7 was a new natural product, and compound 5 was obtained for the first time from the Andrographis species.

A new and known cytotoxic aryltetralin-type lignans from stems of Bursera graveolens.

A new 4alpha-aryltetralin-type lignan called burseranin (1) and a known analogous lignan picropolygamain (2) were isolated along with known triterpenes, lupeol and epi-lupeol from the methanol extract of stems of Bursera graveolens, which showed a remarkable inhibitory activity against human HT1080 fibrosarcoma cells. The whole structure of 1 was established based on combined spectral studies and the absolute structure for 2 was first confirmed by CD spectral evidence. In addition, cytotoxic activities of the stem (methanol) extract and its components are evaluated in this paper.