Essential Oils of Zingiber Species from Vietnam: Chemical Compositions and Biological Activities

Abstract

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.

Pesticidal Activities of Callicarpa and Premna Essential Oils From Vietnam

“…Dias and Moraes 31 have suggested that essential oils with 24-h LC 50 less than 100 μg/mL should be considered to be “active” while LC 50 above 100 μg/mL should be “inactive.” Using this criterion, all of the Callicarpa and Premna essential oils could be considered to be active. Based on our experience, 29,30,32,33 however, we suggest amending the definition of active larvicidal essential oils. Essential oils with 24-h LC 50 <10 μg/mL should be considered “exceptionally active,” those with 24-h LC 50 between 10 μg/mL and 50 μg/mL “very active,” those with 24-h LC 50 between 50 μg/mL and 100 μg/mL “moderately active, and LC 50 > 100 μg/mL are “inactive.” In this case, C. rubella leaf essential oil is exceptionally active against Cx.…”

“…Using this criterion, all of the Callicarpa and Premna essential oils could be considered to be active. Based on our experience, 29,30,32,33 however, we suggest amending the definition of active larvicidal essential oils. Essential oils with 24-h LC 50 <10 μg/mL should be considered "exceptionally active," those with 24-h LC 50 between 10 μg/mL and 50 μg/mL "very active," those with 24-h LC 50 between 50 μg/mL and 100 μg/mL "moderately active, and LC 50 > 100 μg/mL are "inactive."…”

Healthy Zerumbone: From Natural Sources to Strategies to Improve Its Bioavailability and Oral Administration

“…Zerumbone is not always one of the main components of Zingiber spp. rhizome essential oils [ 78 ]. For instance, zerumbone constitutes a minor component in the rhizome oils of Z. cassumunar Roxb.…”

Organoleptic Quality Assessment of Dairy and Nondairy Products Supplemented with Ginger Oil: A Preliminary Study

“…These facts mean that ginger could be an excellent nutraceutical among spices, with anti-diabetic, anti-obesity, cardioprotective, and lipid-lowering effects [16,17]. Furthermore, ginger oil was rich in α-pinene and β-pinene, so it could show the best larval activity [18]. Also ginger oil had excellent antibacterial activity and could inhibit Bacillus cereus, Enterococcus faecalis, Staphylococcus aureus, and so on [18].…”

“…Furthermore, ginger oil was rich in α-pinene and β-pinene, so it could show the best larval activity [18]. Also ginger oil had excellent antibacterial activity and could inhibit Bacillus cereus, Enterococcus faecalis, Staphylococcus aureus, and so on [18]. Therefore, it is true that the importance of research related to ginger and ginger-derived oil is gradually increasing.…”