Chemical composition and antigenotoxic properties of Lippia alba essential oils

The present work evaluated the chemical composition and the DNA protective effect of the essential oils (EOs) from Lippia alba against bleomycin-induced genotoxicity. EO constituents were determined by Gas Chromatography/Mass Spectrometric (GC-MS) analysis. The major compounds encountered being citral (33% geranial and 25% neral), geraniol (7%) and trans-β-caryophyllene (7%) for L. alba specimen COL512077, and carvone (38%), limonene (33%) and bicyclosesquiphellandrene (8%) for the other, COL512078. The genotoxicity and antigenotoxicity of EO and the compounds citral, carvone and limonene, were assayed using the SOS Chromotest in Escherichia coli. The EOs were not genotoxic in the SOS chromotest, but one of the major compound (limonene) showed genotoxicity at doses between 97 and 1549 mM. Both EOs protected bacterial cells against bleomycin-induced genotoxicity. Antigenotoxicity in the two L. alba chemotypes was related to the major compounds, citral and carvone, respectively. The results were discussed in relation to the chemopreventive potential of L. alba EOs and its major compounds.     

Essential oils of medicinal plants from the central andes of Argentina: chemical composition, and antifungal, antibacterial, and insect-repellent activities

The antifungal, antibacterial, and insect‐repellent activities of the essential oils (EOs) of Acantholippia seriphioides, Artemisia mendozana, Gymnophyton polycephalum, Satureja parvifolia, Tagetes mendocina, and Lippia integrifolia, collected in the Central Andes area, province of San Juan, Argentina, were investigated. The dermatophytes Microsporum gypseum, Trichophyton mentagrophytes, and T. rubrum were inhibited by the EOs of G. polycephalum, L. integrifolia, and S. parvifolia, with minimum inhibitory concentrations (MICs) between 31.2 and 1000 μg/ml. Moreover, all EOs presented moderate activity against the bacteria tested, and the L. integrifolia and G. polycephalum EOs showed excellent repellent properties against Triatoma infestans, the Chagas disease vector, with repellency values between 60 and 100%. The A. seriphioides, G. polycephalum, and L. integrifolia EOs, obtained by hydrodistillation, were characterized by GC‐FID and GC/MS analyses. The highest number of components (40) was identified in L. integrifolia EO, which, along with that of A. seriphioides, contained important amounts of oxygenated monoterpenes (44.35 and 29.72%, resp.). Thymol (27.61%) and carvacrol (13.24%) were the main components of A. seriphioides EO, and borneol, lippifoli‐1(6)‐en‐5‐one, and terpinen‐4‐ol (>8.5%) were the principal compounds of L. integrifolia EO. These results support the idea that oxygenated monoterpenes are the bioactive fractions of the EOs. Finally, the study shows that these Andean species might be used to treat superficial fungal infections and to improve the local Chagas disease situation by vector‐control.     

Eutreta xanthochaeta (Diptera: Tephritidae) is unsuitable for biocontrol of Lantana camara in Africa

The stem-galling fly, Eutreta xanthochaeta, was evaluated as a potential agent for biocontrol of the invasive alien plant, Lantana camara, in Africa. Multi-choice trials showed an approximately equal oviposition preference for indigenous Lantana and Lippia species, and the target weed. They were also found to be about equally suitable for fly development. Finally, population sustainability studies indicated that the fly has about as much potential to persist on these indigenous plants as on the target weed. It was concluded that E. xanthochaeta is insufficiently host specific to use for biocontrol of L. camara in Africa.     

Antimicrobial activity of various extracts and carvacrol from Lippia multiflora leaf extract

This study examines the antimicrobial activity of the hexane, dichloromethane and methanol extracts of Lippia multiflora and carvacrol isolated from the hexane extract. The result shows the hexane extract to be the most active, while the methanol extract exhibited no antimicrobial activity. The isolated carvacrol from the hexane fraction showed tremendous antimicrobial activity. These results confirm the traditional uses of Lippia multiflora in the treatment of disease conditions due to microbes.     

柠檬马鞭草快速繁殖技术研究

选择柠檬马鞭草带腋芽的幼嫩茎段为外植体进行快速繁殖。结果表明,腋芽诱导的最适培养基是MS基本培养基附加6-BA0.5～1.0mg／L和IBA0．1～0．3mg／L．外植体腋芽能正常萌发生长,并迅速进入增殖状态,20d转接1次,增殖倍数存3倍以上,最适生根培养基是1／2MS基本培养基附加IBA0．5mg／L,诱导生根率达99％。将生根苗移入苗盆。30d的成活率在85％以上。     

Could the essential oil of Lippia alba provide a readily available and cost-effective anaesthetic for Nile tilapia (Oreochromis niloticus)?

We report the optimal concentration of the essential oil of Lippia alba (EOLA) for the induction and recovery of anesthesia in Nile tilapia (Oreochromis niloticus) during handling. Groups of 10 juveniles were separately subjected to a concentration of EOLA: 0 (control group), 10, 20, 50, 100, 200, 300, or 500 µL L-1. The plasma cortisol levels were significantly decreased in anesthetized fish 4 h after stress of handling. The plasma glucose levels were significantly increased 1 and 4 h after stress of handling in fish exposed to EOLA. Sensory analysis showed that tasters did not detect differences through a blind test in fillet taste and odor between exposed and non-exposed fish. The ideal concentration to promote the best anesthesia and recovery times and to reduce plasma cortisol 4 h after handling is 500 µL L-1.     

In vitro antileishmanial activity and cytotoxicity of essential oil from Lippia sidoides Cham

Leishmaniasis is a widespread tropical infection caused by different species of Leishmania protozoa. There is no vaccine available for Leishmania infections and conventional treatments are very toxic to the patients. Therefore, antileishmanial drugs are urgently needed. In this study we have analyzed the effects of essential oils from Lippia sidoides (LSEO) and its major compound thymol on the growth, viability and ultrastructure of Leishmania amazonensis. The essential oil and thymol showed significant activity against promastigote forms of L. amazonensis, with IC₅₀/48 h of 44.38 and 19.47 μg/mL respectively. However, thymol showed toxicity against peritoneal macrophages and low selectivity against the promastigotes when compared with the crude LSEO. On the other hand, no cytotoxic effect was observed in macrophages treated with the crude essential oil. Incubation of L. amazonensis-infected macrophages with LSEO showed a marked reduction in amastigote survival within the macrophages. Significant morphological alterations as accumulation of large lipid droplets in the cytoplasm, disrupted membrane and wrinkled cells were usually seen in treated parasites. The LSEO's activity against both promastigote and the amstigote forms of L. amazonensis, together with its low toxicity to mammalian cells, point to LSEO as a promising agent for the treatment of cutaneous leishmaniasis.     

Phytochemical Diversity of the Essential Oils of Mexican Oregano (Lippia graveolens Kunth) Populations along an Edapho‐Climatic Gradient

Mexican oregano (Lippia graveolens) is an important aromatic plant, mainly used as flavoring and usually harvested from non‐cultivated populations. Mexican oregano essential oil showed important variation in the essential‐oil yield and composition. The composition of the essential oils extracted by hydrodistillation from 14 wild populations of L. graveolens growing along an edaphoclimatic gradient was evaluated. Characterization of the oils by GC‐FID and GC/MS analyses allowed the identification of 70 components, which accounted for 89–99% of the total oil composition. Principal component and hierarchical cluster analyses divided the essential oils into three distinct groups with contrasting oil compositions, viz., two phenolic chemotypes, with either carvacrol (C) or thymol (T) as dominant compounds (contents >75% of the total oil composition), and a non‐phenolic chemotype (S) dominated by oxygenated sesquiterpenes. While Chemotype C was associated with semi‐arid climate and shallower and rockier soils, Chemotype T was found for plants growing under less arid conditions and in deeper soils. The plants showing Chemotype S were more abundant in subhumid climate. High‐oil‐yield individuals (>3%) were identified, which additionally presented high percentages of either carvacrol or thymol; these individuals are of interest, as they could be used as parental material for scientific and commercial breeding programs.     

Biology and host range of Ophiomyia camarae Spencer (Diptera: Agromyzidae), a potential biocontrol agent for Lantana spp. (Verbenaceae) in Australia

The life history and host range of the herringbone leaf-mining fly Ophiomyia camarae, a potential biological control agent for Lantana spp., were investigated. Eggs were deposited singly on the underside of leaves. Although several eggs can be laid on a single leaf and a maximum of three individual mines were seen on a single leaf, only one pupa per leaf ever developed. The generation time (egg to adult) was about 38 days. Females (mean 14 days) lived longer than males (mean 9 days) and produced about 61 mines. Oviposition and larval development occurred on all five lantana phenotypes tested. Eleven plant species representing six families were tested to determine the host range. Oviposition and larval development occurred on only lantana and another nonnative plant Lippia alba (Verbenaceae), with both species supporting populations over several generations. A CLIMEX model showed that most of the coastal areas of eastern Australia south to 30°16′ S (Coffs Harbour) would be suitable for O. camarae. O. camarae was approved for release in Australia in October 2007 and mines have been observed on plants at numerous field sites along the coast following releases.