There are around 140 species in the genus Callicarpa, with 23 species occurring in Vietnam. The Vietnamese Callicarpa species have been poorly studied. In this work, the leaf essential oils of C. bodinieri, C. candicans, C. formosana, C. longifolia, C. nudiflora, C. petelotii, C. rubella, and C. sinuata, have been obtained from plants growing in central Vietnam. The chemical compositions of the essential oils were determined using gas chromatography – mass spectrometry. Mosquito larvicidal activities of the essential oils were carried out against Aedes aegypti. All of the Callicarpa leaf essential oils showed larvicidal activity, but two samples of C. candicans were particularly active with 48-h LC50 values of 2.1 and 3.8 μg/mL. Callicarpa candicans essential oil should be considered as a potential alternative mosquito control agent.

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. In this work, the leaf essential oils of eleven species of Lauraceae (Beilschmiedia erythrophloia, B. robusta, B. yunnanensis, Cryptocarya concinna, C. impressa, C. infectoria, Litsea viridis, Machilus balansa, M. grandifolia, Neolitsea ellipsoidea, and Phoebe angustifolia) have been obtained by hydrodistillation and the chemical compositions analyzed by gas chromatography – mass spectrometry (GC-MS) and gas chromatography with flame ionization detection (GC-FID). The essential oils were screened for larvicidal activity against Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus, and for antimicrobial activity against Enterococcus faecalis, Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica, and Candida albicans. The leaf essential oil of N. ellipsoidea, rich in (E)-β-ocimene (87.6%), showed excellent larvicidal activity against Ae. aegypti with a 24 h LC50 of 6.59 μg/mL. The leaf essential oil of C. infectoria, dominated by germacrene D (55.5%) and bicyclogermacrene (11.4%), exhibited remarkable larvicidal activity against Cx. quinquefasciatus (48 h LC50 = 0.40 μg/mL). N. ellipsoidea leaf essential oil also demonstrated notable antibacterial activity against E. faecalis and B. cereus with minimum inhibitory concentration (MIC) values of 16 μg/mL, while the leaf essential oil of C. impressa showed excellent anticandidal with an MIC of 16 μg/mL. Leaf essential oils from the Lauraceae should be considered for utilization as alternative agents for controlling mosquito populations and as antimicrobial agents.

Members of the genus Cinnamomum (Lauraceae) have aromatic volatiles in their leaves and bark and some species are commercially important herbs and spices. In this work, the essential oils from five species of Cinnamomum (C. damhaensis, C. longipetiolatum, C. ovatum, C. polyadelphum and C. tonkinense) growing wild in north central Vietnam were obtained by hydrodistillation, analyzed by gas chromatography and screened for antimicrobial and mosquito larvicidal activity. The leaf essential oil of C. tonkinense, rich in β-phellandrene (23.1%) and linalool (32.2%), showed excellent antimicrobial activity (MIC of 32 μg/mL against Enterococcus faecalis and Candida albicans) and larvicidal activity (24 h LC50 of 17.4 μg/mL on Aedes aegypti and 14.1 μg/mL against Culex quinquefasciatus). Cinnamomum polyadelphum leaf essential oil also showed notable antimicrobial activity against Gram-positive bacteria and mosquito larvicidal activity, attributable to relatively high concentrations of neral (11.7%) and geranial (16.6%). Thus, members of the genus Cinnamomum from Vietnam have shown promise as antimicrobial agents and as potential vector control agents for mosquitoes.

Essential oils have emerged as viable alternatives to synthetic insecticides for control of mosquito-borne pathogens. The leaf essential oils of eight species of Premna (Lamiaceae) growing in central Vietnam have been obtained by hydrodistillation and analyzed by gas chromatography–mass spectrometry. Sesquiterpene hydrocarbons dominated most of the Premna essential oils, with the notable exception of Premnamekongensis from Ngoc Linh Nature Reserve, which had α-pinene as the major component. Larvicidal activities against Aedes aegypti have been determined and all of the Premna essential oils showed larvicidal activity with 24-h LC50 < 65 μg/mL. The leaf essential oils of Premnacambodiana from Chu Mom Ray National Park and Premnamekongensis from Ngoc Linh Nature Reserve showed the best larvicidal activities with 24-h LC50 of 16.8 and 18.0 μg/mL, respectively. The essential oil compositions and larvicidal activities of P. cambodiana, Premna flavescens, Premnamaclurei, P. mekongensis, and Premnapuberula are reported for the first time. Although the larvicidal activities of Premna leaf essential oils are promising, the essential oil yields are relatively low (0.10–0.25%).

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. As part of a program to identify essential oils as alternative larvicidal and antimicrobial agents, the leaf, stem, and rhizome essential oils of several Zingiber species, obtained from wild-growing specimens in northern Vietnam, were acquired by hydrodistillation and investigated using gas chromatography. The mosquito larvicidal activities of the essential oils were assessed against Culex quinquefasciatus, Aedes albopictus, and Ae. aegypti, and for antibacterial activity against a selection of Gram-positive and Gram-negative bacteria, and for activity against Candida albicans. Zingiber essential oils rich in α-pinene and β-pinene showed the best larvicidal activity. Zingiber nudicarpum rhizome essential oil showed excellent antibacterial activity against Enterococcus faecalis, Staphylococcus aureus, and Bacillus cereus, with minimum inhibitory concentrations (MIC) of 2, 8, and 1 μg/mL, respectively. However, the major components, α-pinene and β-pinene, cannot explain the antibacterial activities obtained.

Leaves of Actinodaphne pilosa were collected at 2 different seasons from the Pù Hoạt Nature Reserve, Vietnam. The leaf samples were hydrodistilled to give essential oils, which were analyzed by gas chromatography (GC)–mass spectrometry and GC-flame ionization detection. The major components in the essential oils were α-pinene, ( Z)-β-ocimene, ( E)-β-ocimene, β-caryophyllene, germacrene D, bicyclogermacrene, and spathulenol. The essential oils were screened for antimicrobial activity against Enterococcus faecalis, Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans, as well as mosquito larvicidal activity against Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus. Actinodaphne pilosa leaf essential oils showed broad antimicrobial activity (minimum inhibitory concentration = 32, 64, 64, 16, and 16 μg/mL against E. faecalis, S. aureus, B. cereus, P. aeruginosa, and C. albicans, respectively) and excellent larvicidal activity (24-hour 50% lethal concentration = 19.0, 24.7, and 48.1 μg/mL against A. aegypti, A. albopictus, and C. quinquefasciatus, respectively).

No abstract

Background: Oleanolic acid is an oleanane triterpene found in many plant species all over the world. This compound is also a major saponin in leaves of Polyscias fruticosa and possess several promising pharmacological activities, such as hepatoprotective effects, and anti-inflammatory, antioxidant, or anticancer activities. Objective: The objective of the present work is to establish cell suspension culture of P. fruticosa, investigate influence of several factors such as plant growth regulators and carbon source on cell growth, and determine their oleanolic acid content. Method: Cell culture was carried out by using 2 g fresh weight of 30 day old friable callus derived from in vitro stem segment in 50 mL of liquid medium with a shaking speed of 120 rpm. Culture was then incubated at 25±2ºC with a shaking speed of 120 rpm in the period of 12 h daylight at light intensity of about 6.75 µmol/m2 /s. Cell growth was measured by fresh and dry biomass at 16h day. Oleanolic acid content was determined using HPLC analysis. Results & Discussion: The study results showed that MS medium containing 2% sucrose as a carbon source, supplemented with 1 mg/L 6-benzylaminopurine and 0.5 mg/L 2,4-D dichlorophenoxyacetic acid was the most appropriate growth medium. Cell biomass and oleanolic acid content reached the highest values of 0.43 g dry weight/flask and 25.4 mg/g dry weight, respectively. Conclusion: These results indicated the potential production of oleanolic acid, a compound with high pharmacological value, from P. fruticosa cell culture.