Therapeutic Applications of Essential Oils from Native and Cultivated Ecuadorian Plants: Cutaneous Candidiasis and Dermal Anti-Inflammatory Activity.

Essential oils are a complex mixture of aromatic substances whose pharmacological actions, including antimicrobial, antioxidant, anticancer, and anti-inflammatory activities, have been widely reported. This study aimed to evaluate the anti-Candida and dermal anti-inflammatory activity of essential oils from native and cultivated Ecuadorian plants. Essential oils from Bursera graveolens, Dacryodes peruviana, Mespilodaphne quixos, and Melaleuca armillaris were isolated by hydrodistillation and were characterized physically and chemically. Its tolerance was analyzed by in vitro and in vivo studies. The antifungal activity was studied against Candida albicans, Candida glabrata, and Candida parapsilosis, whereas the anti-inflammatory effect was evaluated by a mouse ear edema model. The main compounds were limonene, α-phellandrene, (E)-methyl cinnamate, and 1,8-cineole, respectively. All essential oils showed high tolerability for skin application, antifungal activity against the three Candida strains, and anti-inflammatory efficacy by decreasing edema and overexpression of pro-inflammatory cytokines. Dacryodes peruviana essential oil showed the highest antifungal activity. On the other hand, Dacryodes peruviana and Melaleuca armillaris showed the greatest anti-inflammatory potential, decreasing edema by 53.3% and 65.25%, respectively, and inhibiting the overexpression of TNF-α, IL-8, IL-17A, and IL-23. The results suggest that these essential oils could be used as alternative therapies in the treatment of both cutaneous candidiasis and dermal inflammation.

Development of a Topical Amphotericin B and Bursera graveolens Essential Oil-Loaded Gel for the Treatment of Dermal Candidiasis.

The higher molecular weight and low solubility of amphotericin B (AmB) hinders its topical administration. The aim of this study was to incorporate Bursera graveolens essential oil into an AmB topical gel (AmB + BGEO gel) in order to promote the diffusion of the drug through the skin in the treatment of cutaneous candidiasis. AmB + BGEO gel formulation was determined using a factorial experiment. Physical and chemical parameters, stability, in vitro release profile and ex vivo permeation in human skin were evaluated. In vitro antimicrobial activity was studied using strains of C. albicans, C. glabrata and C. parapsilosis. The tolerability was evaluated using in vitro and in vivo models. AmB + BGEO gel presented appropriate characteristics for topical administration, including pH of 5.85, pseudoplastic behavior, optimal extensibility, as well as high stability and acceptable tolerability. In vitro release studies showed that the formulation releases the drug following a Boltzmann sigmoidal model. Finally, AmB + BGEO gel exhibited higher amount of drug retained inside the skin and lower Minimum Inhibitory Concentration than a formulation sans essential oil. Therefore, these results suggest that the incorporation of B. graveolens essential oil in the formulation could be used as strategy to promote a local effect in the treatment of cutaneous candidiasis.

Shewanella vesiculosa sp. nov., a psychrotolerant bacterium isolated from an Antarctic coastal area.

Two strains of psychrotolerant bacteria, designated M7(T) and M5, isolated from Antarctic coastal marine environments were studied to determine their taxonomic position. The organisms comprised Gram-negative, rod-shaped, facultatively anaerobic cells that were motile by means of single polar flagella. Neither of the bacterial isolates had a requirement for Na(+). These two psychrotolerant strains grew at temperatures ranging from -4 to 30 degrees C. Both strains were capable of producing H(2)S from thiosulfate and were able to use sodium nitrate and trimethylamine N-oxide as terminal electron acceptors during anaerobic growth. 16S rRNA gene sequence analysis placed M7(T) and M5 within the genus Shewanella; the strains showed the highest similarity (99.9 and 99.2 % respectively) with respect to the type strains of Shewanella livingstonensis and Shewanella frigidimarina. However the levels of gyrB sequence similarity between strain M7(T) and the type strains of S. livingstonensis and S. frigidimarina were 87.6 and 87.4 %, respectively. DNA-DNA hybridization experiments performed between the Antarctic isolate M7(T) and S. livingstonensis LMG 19866(T) and S. frigidimarina LMG 19475(T) revealed levels of relatedness of 32 and 35 %, respectively. Strain M5 showed 100 % DNA relatedness with respect to strain M7(T). The DNA G+C content of these bacteria was 42 mol%. Several phenotypic characteristics, the cellular fatty acid compositions and the quinone content of strains M7(T) and M5 served to differentiate them from related shewanellae. On the basis of the data from this polyphasic taxonomic study, M7(T) and M5 constitute a single genospecies. They represent a novel species of the genus Shewanella, for which the name Shewanella vesiculosa sp. nov. is proposed. The type strain is M7(T) (=LMG 24424(T) =CECT 7339(T)).

Marinobacter guineae sp. nov., a novel moderately halophilic bacterium from an Antarctic environment.

Two Gram-negative, cold-adapted, moderately halophilic, aerobic bacteria, designated strains M3B(T) and M3T, were isolated from marine sediment collected from the South Shetland Islands, Antarctica. The organisms were rod-shaped, catalase- and oxidase-positive, and motile by means of polar flagella. These two psychrotolerant strains required Na(+) and grew at NaCl concentrations of 1-15 % and temperatures between 4 and 42 degrees C. 16S rRNA gene sequence analysis placed strains M3B(T) and M3T within the genus Marinobacter. DNA-DNA hybridization experiments between the Antarctic isolate M3B(T) and type strains of phylogenetically related species, namely Marinobacter lipolyticus, Marinobacter flavimaris, Marinobacter sediminum, Marinobacter algicola, Marinobacter maritimus and Marinobacter koreensis, revealed levels of relatedness lower than 32 %. Strain M3T showed 99 % DNA relatedness to strain M3B(T). The DNA G+C contents of M3B(T) and M3T were 57.1 and 57.4 mol%, respectively, and their major isoprenoid quinone was ubiquinone-9. Several phenotypic characteristics, together with data on cellular fatty acid composition, served to differentiate strains M3B(T) and M3T from strains of related Marinobacter species. On the basis of the polyphasic taxonomic evidence presented in this study, it can be concluded that strains M3B(T) and M3T belong to the same genospecies and represent a novel species of the genus Marinobacter, for which the name Marinobacter guineae sp. nov. is proposed. The type strain is M3B(T) (=LMG 24048(T)=CECT 7243(T)).

Pseudomonas guineae sp. nov., a novel psychrotolerant bacterium from an Antarctic environment.

Two Gram-negative, cold-adapted, aerobic bacteria, designated strains M8T and M6, were isolated from soil collected from the South Shetland Islands. The organisms were rod-shaped, catalase- and oxidase-positive and motile by means of polar flagella. These two psychrotolerant strains grew between -4 and 30 degrees C. 16S rRNA gene sequence analysis placed strains M8T and M6 within the genus Pseudomonas. DNA-DNA hybridization experiments between the Antarctic isolate M8T and type strains of phylogenetically related species, namely Pseudomonas peli and Pseudomonas anguilliseptica, revealed levels of relatedness of 33 and 37%, respectively. Strain M6 showed 99% DNA similarity to strain M8T. Several phenotypic characteristics, together with data on cellular fatty acid composition, served to differentiate strains M8T and M6 from related pseudomonads. On the basis of the polyphasic taxonomic evidence presented in this study, it can be concluded that strains M8T and M6 belong to the same genospecies, representing a novel species of the genus Pseudomonas, for which the name Pseudomonas guineae sp. nov. is proposed. The type strain is M8T (=LMG 24016T=CECT 7231T).

Characterization of several Psychrobacter strains isolated from Antarctic environments and description of Psychrobacter luti sp. nov. and Psychrobacter fozii sp. nov.

Eleven psychrophilic bacteria isolated from Antarctic coastal marine environments were subjected to a polyphasic taxonomic study. The isolates were oxidase-positive, halotolerant, gram-negative, non-motile coccobacilli with a strictly oxidative metabolism. The DNA G + C content ranged from 44 to 47 mol%. DNA-DNA hybridization experiments showed six homology groups, two of them related at the species level to the type strain of Psychrobacter immobilis, LMG 7203T (70-83%). The highest DNA relatedness of two other groups to known Psychrobacter species was found to the type strain of Psychrobacter glacincola, LMG 21282T (51-57%), and no significant similarity was found between Psychrobacter type strains and the last two groups. The predominant cellular fatty acids detected were typical of the genus Psychrobacter and included 18:1omega9c, 16:1omega7c and 17:1omega8c. 16S rRNA gene sequence analysis confirmed that the strains isolated belonged to the genus Psychrobacter. The results of the study assigned five isolates to P. immobilis, three isolates to P. glacincola and three isolates to novel Psychrobacter species. The names Psychrobacter luti sp. nov. (type strain NF11T=LMG 21276T=CECT 5885T) and Psychrobacter fozii sp. nov. (type strain NF23T=LMG 21280T=CECT 5889T) are proposed for these organisms.

Shewanella frigidimarina and Shewanella livingstonensis sp. nov. isolated from Antarctic coastal areas.

Three strains of psychrophilic bacteria isolated from Antarctic coastal marine environments were studied to determine their taxonomic position. These bacteria were gram-negative rods, facultatively anaerobic and motile by means of a single polar flagellum. None of the bacterial isolates had an Na+ requirement. Only one of the strains was capable of producing H2S from thiosulfate. The DNA base content of these bacteria was 41-42 mol % G+C. DNA-DNA hybridization experiments showed that the isolates formed two related groups that exhibited about 70 and 24% DNA-DNA homology, respectively, with the type strain of Shewanella frigidimarina. The fatty acid profiles of the bacterial isolates were similar to the profiles of other Shewanella species. All the strains contained both ubiquinones and menaquinones, like Shewanella species. Methylmenaquinones were also found. 16S rRNA gene analysis confirmed that isolated strains belonged to the genus Shewanella and were phylogenetically related to the newly identified Shewanella frigidimarina. The results of the polyphasic taxonomic study assigned the three isolates to Shewanella and two of them specifically to Shewanella frigidimarina. The name Shewanella livingstonensis sp. nov. (type strain LMG 19866T) is proposed for the third organism.