Chemical Composition, Repellent Action, and Toxicity of Essential Oils from Lippia origanoide, Lippia. alba Chemotypes, and Pogostemon cablin on Adults of Ulomoides dermestoides (Coleoptera: Tenebrionidae)

Antifungal activity of Allium tuberosum (AT), Cinnamomum cassia (CC), and Pogostemon cablin (Patchouli, P) essential oils against Aspergillus flavus strains 3.2758 and 3.4408 and Aspergillus oryzae was tested at 2 water activity levels (aw : 0.95 and 0.98). Main components of tested essential oils were: allyl trisulfide 40.05% (AT), cinnamaldehyde 87.23% (CC), and patchouli alcohol 44.52% (P). The minimal inhibitory concentration of the plant essential oils against A. flavus strains 3.2758 and 3.4408 and A. oryzae was 250 ppm (A. tuberosum and C. cassia), whereas Patchouli essential oil inhibited fungi at concentration > 1500 ppm. The essential oils exhibited suppression effect on colony growth at all concentrations (100, 175, and 250 ppm for A. tuberosum; 25, 50, and 75 for C. cassia; 100, 250, and 500 for P. cablin essential oil). Results of the study represent a solution for possible application of essential oil of C. cassia in different food systems due to its strong inhibitory effect against tested Aspergillus species. In real food system (table grapes), C. cassia essential oil exhibited stronger antifungal activity compared to cinnamaldehyde.

Panax notoginseng (Burkill) F.H.Chen (Araliaceae), of which the dry root and rhizome are precious traditional Chinese medicine, suffers severely from diseases during planting. Essential oils (EOs) with antimicrobial activity are a possibility for the development of green pesticides. We extracted EOs from Pogostemon cablin (Blanco) Benth. and Eupatorium fortunei Turcz., respectively and tested their inhibitory rates on fungi isolated from diseased P. notoginseng by the Oxford cup method. The compounds of the EO were identified by GC/MS and the minimum inhibitory concentrations (MICs) of the EOs and their main components were evaluated by the 96-well plate method. We also mixed P. cablin EO, E. fortunei EO and hymexazol in pairs to explore whether their combinations produce stronger antifungal effects than individual components. Finally, we evaluated the effects of the EOs against Fusarium oxysporum in vivo. P. cablin EO and E. fortunei EO exhibited different antifungal activities against fungi, with the inhibitory rates of 21.02 %-100 % and 54.84 %-100 % and MICs of 0.07-0.88 mg/mL and 0.20-1.17 mg/mL, respectively. Pogostone (24.96 %) and thymol (15.64 %) were the major compounds of P. cablin EO and E. fortunei EO, respectively, and they exhibited stronger antifungal activities than EOs, with MICs of 0.008-0.078 mg/mL and 0.12-0.31 mg/mL, respectively. Moreover, hymexazol was mixed with E. fortunei EO, and the inhibitory effect against Cylindrocarpon destructans was enhanced with a synergistic effect. The disease incidence and disease index of EO treatments decreased significantly in vivo. Based on our study, P. cablin EO and E. fortunei EO have great potential to be developed into green fungicides for use in agriculture to control diseases of P. notoginseng.

ABSTRACT: The aim of this study was to investigate the anesthetic effect of the essential oils (EOs) of Lippia alba (citral and linalool chemotypes, EOLA-C and EOLA-L respectively) and Lippia origanoides (chemotype carvacrol, EOLO-Ca) on tambaqui (Colossoma macropomum) juveniles. The tested concentrations of the L. alba and L. origanoides EOs were: 25, 50, 100, and 200 μL/L. Time required to reach the stages of sedation, deep anesthesia, and recovery, as well as ventilatory frequency, were monitored for each EO concentration. The results indicated that all EO concentrations tested induced tambaqui anesthesia and that the ventilatory frequency was altered by the EOs. L. origanoides showed the shortest time to induce sedation and anesthesia, but had long recovery times. L. alba EO (citral 100 μL/L and linalool 200 μL/L) can be used to efficiently anaesthetise tambaqui juveniles with an efficient recovery.

This study was conducted to assess the repellent activity of Pogostemon cablin (Blanco) Benth. [Lamiaceae] essential oil (EO) and its nanoemulsion (NE) against Haemaphysalis longicornis nymphs. Pogostemon cablin EO nanoemulsion (PCNE) was prepared by ultrasonic emulsification using P. cablin EO and a surfactant, Tween 80. The results of gas chromatography–mass spectrometry analysis showed that the major component of P. cablin EO was patchouli alcohol (32.04%), followed by δ-guaiene (18.13%), α-guaiene (16.76%), seychellene (7.49%), and β-patchoulene (5.09%). The droplet sizes of PCNEs formulated using P. cablin EO and Tween 80 in ratios of 1:1, 1:2, and 1:3 were 23.8, 20.1 and 17.7 nm, respectively, indicating that the increase in the ratio of Tween 80 led to a decrease in droplet size. All essential oil preparations had an acceptable polydispersity index of 0.5 or less. The P. cablin EO and Tween 80 ratio of 1:3 was selected as the optimal formulation with the smallest droplet size; transmission electron microscopy indicated the formation of uniform spherical droplets. PCNE (84.0%) showed a higher repellent activity against H. longicornis nymphs than P. cablin EO (72.0%). The nanoemulsion is suitable for improving the repellent activity of P. cablin EO and is a potential repellent for H. longicornis.

Lippia alba (Miller) N.E. Brown is an aromatic plant known locally as “Erva-cidreira-do-campo” that has great importance in Brazilian folk medicine. The aim of our study was to evaluate the antidermatophytic potential of linalool-rich essential oil (EO) from L. alba and analyze the ability of this EO to inhibit peptidase and keratinase activities, which are important virulence factors in dermatophytes. The minimum inhibitory concentrations (MICs) of L. alba EO were 39, 156 and 312 µg/mL against Trichophyton rubrum, Epidermophyton floccosum and Microsporum gypseum, respectively. To evaluate the influence of L. alba EO on the proteolytic and keratinolytic activities of these dermatophytes, specific inhibitory assays were performed. The results indicated that linalool-rich EO from L. alba inhibited the activity of proteases and keratinases secreted from dermatophytes, and this inhibition could be a possible mechanism of action against dermatophytes. Due to the effective antidermatophytic activity of L. alba EO, further experiments should be performed to explore the potential of this linalool-rich EO as an alternative antifungal therapy.

The chemical compositions and larvicidal potential against mosquito vectors of selected essential oils obtained from five edible plants were investigated in this study. Using a GC/MS, 24, 17, 20, 21, and 12 compounds were determined from essential oils of Citrus hystrix, Citrus reticulata, Zingiber zerumbet, Kaempferia galanga, and Syzygium aromaticum, respectively. The principal constituents found in peel oil of C. hystrix were beta-pinene (22.54%) and d-limonene (22.03%), followed by terpinene-4-ol (17.37%). Compounds in C. reticulata peel oil consisted mostly of d-limonene (62.39%) and gamma-terpinene (14.06%). The oils obtained from Z. zerumbet rhizome had alpha-humulene (31.93%) and zerumbone (31.67%) as major components. The most abundant compounds in K. galanga rhizome oil were 2-propeonic acid (35.54%), pentadecane (26.08%), and ethyl-p-methoxycinnamate (25.96%). The main component of S. aromaticum bud oil was eugenol (77.37%), with minor amounts of trans-caryophyllene (13.66%). Assessment of larvicidal efficacy demonstrated that all essential oils were toxic against both pyrethroid-susceptible and resistant Ae. aegypti laboratory strains at LC50, LC95, and LC99 levels. In conclusion, we have documented the promising larvicidal potential of essential oils from edible herbs, which could be considered as a potentially alternative source for developing novel larvicides to be used in controlling vectors of mosquito-borne disease.

The control of Rhipicephalus microplus (Ixodida: Ixodidae) is achieved using synthetic acaricides. However, resistant tick populations are widespread around the world. Plant essential oils can act as repellents, keeping ticks away from hosts and decreasing the selection pressure on synthetic acaricides. The aim of this study was to evaluate the in vitro repellent effect of Lippia alba essential oil on R. microplus larvae. Leaves from two L. alba genotypes maintained under the same agronomic and environmental conditions were collected. Essential oil was extracted by hydrodistillation and analysed by gas chromatography-mass spectrometry (GC-MS). The major monoterpenes detected in the chemical analysis were commercially acquired and tested. For the repellency test, a glass rod was vertically fixed to measure active climbing of approximately 30 R. microplus larvae aged 14-21 days in response to essential oils and monoterpenes. Repellency was evaluated at 1 h, 3 h and 5 h after treatment. Variation in repellent action was detected between the genotypes. The major monoterpenes identified in the essential oils (limonene and carvone) showed low repellent effects in comparison with intact essential oils. Thus, the present results showed that L. alba essential oil contains bioactive compounds with great repellent activity against ticks that varies according to the plant genotype.

Differential anti-proliferative effect on K562 leukemia cells of Lippia alba (Verbenaceae) essential oils produced under diverse growing, collection and extraction conditions

The essential oil was obtained from the aerial parts of Pogostemon cablin by hydrodistillation. The chemical compounds of P. cablin essential oil were analyzed by gas chromatography-flame ionization detection and gas chromatography-mass spectrometry. Eight compounds were totally identified and accounted for 92.4% of the oil. Patchoulol was the major component (51.1%), followed by phloroacetophenone (23.5%) and β-patchoulene (7.3%). The essential oil and its two major compounds patchoulol and phloroacetophenone were evaluated for their contact and repellent activities against Tribolium castaneum, Lasioderma serricorne, and Liposcelis bostrychophila. Results of bioassays indicated that the essential oil and patchoulol had great contact toxicity against three species of insects. Meanwhile, the essential oil and patchoulol showed great repellent activities against T. castaneum and L. bostrychophila but were mildly repellent to L. serricorne. Phloroacetophenone exhibited neither contact nor repellent activity against any of these target insects. This work emphasized the promising potential of P. cablin to control insect pests during storage.

A erva-cidreira [Lippia alba (Mill.) N.E.Brown] é uma espécie nativa utilizada como planta medicinal em todo o Brasil. O citral é responsável pela ação sedativa da erva cidreira, sendo um dos principais componentes do óleo essencial. O objetivo deste trabalho foi avaliar o comportamento agronômico, teor e rendimento de óleo essencial e de citral em 17 acessos de L. alba da coleção da Universidade de Brasília - UnB. O experimento foi realizado no período de 19/02/2005 a 18/03/2006, em latossolo vermelho, no Distrito Federal. O delineamento experimental utilizado foi o de blocos ao acaso, com três repetições, contendo três plantas por parcela. Foram avaliados os parâmetros área foliar, comprimento da haste, produção de massa fresca (folhas e hastes), produção de massa foliar seca, teor de óleo essencial e de citral, rendimento estimado de óleo essencial e de citral por planta, além da caracterização do perfil aromático do óleo essencial. Os acessos L.41 (0,75%), L.45 (0,66%) e L.08 (0,62%) apresentaram os maiores teores de óleo essencial. O acesso L.45 (1,32 g pl-1) apresentou o maior rendimento de óleo, seguido dos acessos L.47 (0,73 g pl-1), L.41 (0,67 g pl-1), L.34 (0,67 g pl-1) e L.33 (0,62 g pl-1). Os acessos apresentaram teores de citral variando de 51,7% (L.34) a 75,1% (L.09), com média de 63,6% e predominância do isômero geranial (36,4%) sobre o neral (27,8%). O acesso L.45 (0,83 g pl-1) apresentou o maior rendimento de citral. Treze acessos apresentaram o quimiotipo citral; três o quimiotipo citral-limoneno e apenas um apresentou o quimiotipo citral-mirceno. Os resultados evidenciam o potencial de produção de citral do acesso L.45, o qual poderá ser utilizado para melhorar a qualidade da matéria prima de erva-cidreira utilizada nos programas de fitoterapia no país ou em programas de melhoramento genético para esta finalidade.

Addition of Lippia alba (Mill) N. E. Brown essential oil to the diet of the silver catfish: An analysis of growth, metabolic and blood parameters and the antioxidant response

BackgroundChagas Disease caused by Trypanosoma cruzi infection, is one of the most important neglected tropical diseases (NTD), without an effective therapy for the successful parasite eradication or for the blocking of the disease’s progression, in its advanced stages. Due to their low toxicity, wide pharmacologic spectrum, and potential synergies, medicinal plants as Lippia alba, offer a promising reserve of bioactive molecules. The principal goal of this work is to characterize the inhibitory properties and cellular effects of the Citral and Carvone L. alba chemotype essential oils (EOs) and their main bioactive terpenes (and the synergies among them) on T. cruzi forms.MethodsTwelve L. alba EOs, produced under diverse environmental conditions, were extracted by microwave assisted hydrodistillation, and chemically characterized using gas chromatography coupled mass spectrometry. Trypanocidal activity and cytotoxicity were determined for each oil, and their major compounds, on epimastigotes (Epi), trypomastigotes (Tryp), amastigotes (Amas), and Vero cells. Pharmacologic interactions were defined by a matrix of combinations among the most trypanocidal terpenes (limonene, carvone; citral and caryophyllene oxide). The treated cell phenotype was assessed by fluorescent and optic microscopy, flow cytometry, and DNA electrophoresis assays.ResultsThe L. alba EOs displayed significant differences in their chemical composition and trypanocidal performance (p = 0.0001). Citral chemotype oils were more trypanocidal than Carvone EOs, with Inhibitory Concentration 50 (IC50) of 14 ± 1.5 μg/mL, 22 ± 1.4 μg/mL and 74 ± 4.4 μg/mL, on Epi, Tryp and Amas, respectively. Limonene exhibited synergistic interaction with citral, caryophyllene oxide and Benznidazole (decreasing by 17 times its IC50) and was the most effective and selective treatment. The cellular analysis suggested that these oils or their bioactive terpenes (citral, caryophyllene oxide and limonene) could be inducing T. cruzi cell death by an apoptotic-like mechanism.ConclusionsEOs extracted from L. alba Citral chemotype demonstrated significant trypanocidal activity on the three forms of T. cruzi studied, and their composition and trypanocidal performance were influenced by production parameters. Citral, caryophyllene oxide, and limonene showed a possible induction of an apoptotic-like phenotype. The best selective anti-T. cruzi activity was achieved by limonene, the effects of which were also synergic with citral, caryophyllene oxide and benznidazole.

The anesthetic efficacy of eugenol and the essential oils of Lippia alba and Aloysia triphylla in post-larvae and sub-adults of Litopenaeus vannamei (Crustacea, Penaeidae)

Pogostemon cablin Benth., an aromatic plant species yields essential oil with immense industrial as well as pharmaceutical applications. In the backdrop of promoting organic cultivation of crops yielding essential oil and related products, the present investigation was designed to evaluate the influence of organic nutrients on growth, yield and essential oil composition of Pogostemon cablin under foothill conditions of Arunachal Pradesh. Different organic nutrients such as FYM (Farmyard manure)@10t/ha; FYM@15t/ha; Vermicompost@5t/ha; Vermicopost@7.5t/ha; Neem cake@1.5t/ha; Neem cake@2.5t/ha; were applied and compared with the check NPK@150:50:50 kg/ha under Randomized Block Design in open field conditions and their influence was observed on plant height, number of branches per plant, collar diameter, herbage yield (fresh and dry), essential oil yield and essential oil composition. It can be concluded that depending upon the requirements of P. cablin essential oil or fresh/dried herbage, as well as essential oil composition the conditions and composition of organic nutrients varies. Present investigation recommends application of vermicompost@7.5t/ha for high essential oil yield, FYM@10t/ha for dried and NPK@150:50:50 kg/ha for fresh herbage yield respectively, while maximum patchouli alcohol content can be obtained in the essential oil extracted from the plants where no input is given.

Insecticidal and repellent activities of Cymbopogon citratus (Poaceae) essential oil and its terpenoids (citral and geranyl acetate) against Ulomoides dermestoides