Publications by authors named "Do Ngoc Dai"

The current research describes a phytochemical analysis and antimicrobial activity of essential oils extracted from the leaves of two Vietnamese Annonaceae species Goniothalamus yunnanensis W.T.Wang and G.

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Cytotoxic, antioxidative, and antimicrobial activities of , and its chemical compositions were first provided in the current study. Phenolic contents in the methanol extracts of its leaves and flowers were 222.73 ± 0.

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The essential oils of five Vietnamese species (, , , , and ) were first hydro-distilled and analyzed using GC-FID/MS (gas chromatography-flame ionization detection/mass spectrometry). Monoterpene hydrocarbons, sesquiterpene hydrocarbons, and oxygenated sesquiterpenoids were the main chemical classes in these oils. All these essential oils showed good-excellent antimicrobial activities against Gram-positive bacteria , , and , and the yeast leaf essential oil, rich in bicyclogermacrene (25.

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The current study describes the chemical identification, antimicrobial, and mosquito larvicidal activities of essential oils from and , growing in Vietnam. Essential oils were extracted from the leaves and rhizomes, and characterized by the GC-FID/MS (gas chromatography-flame ionization detection/mass spectrometry) analysis. Monoterpenes (33.

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There is an ongoing interest to identify alternative pesticidal agents to avoid the chronic problems associated with synthetic pesticides. Essential oils have shown promise as botanical pest control agents. In the present study, the essential oils of four members of the Lamiaceae (Callicarpa candicans, C.

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Mosquitoes, in addition to being a biting nuisance, are vectors of several pathogenic viruses and parasites. As a continuation of our work identifying abundant and/or invasive plant species in Vietnam for use as ecologically friendly pesticidal agents, we obtained the essential oils of , , , , and ; analyzed the essential oils using gas chromatographic techniques; and screened the essential oils for mosquito larvicidal activity against and . The most active larvicidal essential oils were , which was rich in thymohydroquinone dimethyl ether (29.

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Essential oils are promising as environmentally friendly and safe sources of pesticides for human use. Furthermore, they are also of interest as aromatherapeutic agents in the treatment of Alzheimer's disease, and inhibition of the enzyme acetylcholinesterase (AChE) has been evaluated as an important mechanism. The essential oils of some species in the genera , , and of the family Lamiaceae were evaluated for inhibition of electric eel AChE using the Ellman method.

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Lantana camara is a troublesome invasive plant introduced to many tropical regions, including Southeast Asia. However, the plant does hold promise as a source of essential oils that may be explored for potential use. Fresh water snails such as Pomacea canaliculata, Gyraulus convexiusculus, and Tarebia granifera can be problematic agricultural pests as well as hosts for parasitic worms.

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Mosquito-borne infectious diseases are a persistent problem in tropical regions of the world, including Southeast Asia. Vector control has relied principally on synthetic insecticides, but these have detrimental environmental effects and there is an increasing demand for plant-based agents to control insect pests. Invasive weedy plant species may be able to serve as readily available sources of essential oils, some of which may be useful as larvicidal agents for control of mosquito populations.

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Mosquito-borne diseases are a large problem in Vietnam as elsewhere. Due to environmental concerns regarding the use of synthetic insecticides as well as developing insecticidal resistance, there is a need for environmentally-benign alternative mosquito control agents. In addition, resistance of pathogenic microorganisms to antibiotics is an increasing problem.

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Essential oils have emerged as viable alternatives to synthetic insecticides for control of mosquito-borne pathogens. The leaf essential oils of eight species of (Lamiaceae) growing in central Vietnam have been obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry. Sesquiterpene hydrocarbons dominated most of the essential oils, with the notable exception of from Ngoc Linh Nature Reserve, which had α-pinene as the major component.

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The Lauraceae is a family rich in aromatic and medicinal plants. Likewise, essential oils derived from members of this family have demonstrated a myriad of biological activities. It is hypothesized that members of the Lauraceae from Vietnam will yield essential oils that may be useful in controlling mosquito populations and treating microbial infections.

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Mosquitoes are important vectors of several diseases, and control of these insects is imperative for human health. Insecticides have proven useful in controlling mosquito populations, but insecticide resistance and environmental concerns are increasing. Additionally, emerging and re-emerging microbial infections are problematic.

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Mosquitoes are the deadliest animals on earth and are the vectors of several neglected tropical diseases. Recently, essential oils have emerged as potential renewable, cost-effective, and environmentally benign alternatives to synthetic pesticides for control of mosquitoes. In this work, thirteen species of were collected from different areas of central Vietnam.

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Mosquito-borne infections are a constant problem in Vietnam, and mosquito vector control is a primary approach to control these infections. Essential oils represent environmentally friendly alternatives to synthetic pesticides for mosquito control. The essential oils of two weedy species in Vietnam, and , have been obtained by hydrodistillation and analyzed by gas chromatography⁻mass spectrometry.

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Together with twelve known compounds (2-13), melodamide A (1), a new phenolic amide possessing p-quinol moiety, was purified and characterized from the methanolic extracts of the leaves of Melodorum fruticosum. The structure of melodamide A (1) was established with a combination of 2D NMR experiments, HR-ESI-MS and X-ray analyses. The other known compounds were identified by comparison of their spectroscopic and physical data with those reported in the literature.

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The leaf essential oils of five Desmos species from Vietnam have been extracted by steam distillation and subjected to GC and GC-MS analyses. The plant samples were Desmos cochinchinensis Lour., D.

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Further investigation of the methanolic extract of Fissistigma latifolium resulted in two new compounds whose structures were assigned as 2,5,6,7-tetramethoxyflavan (1) and 2'-hydroxy-4',5',6'-trimethoxybenzil (2). These two compounds were determined on the basis of chemical and spectroscopic evidences. Compound 2 is the first report of benzil from Fissistigma species.

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