Responses of Cymbopogon schoenanthus to salt stress

Cymbopogon schoenanthus is an aromatic and medicinal plant rich in essential oil. The physiological behavior of this species, related with growth production, the photosynthetic pigments, the nutritional status and the osmotic adjustment were studied. Saline treatments varied from 0 to 150 mM NaCl. The results show that the growth of C. schoenanthus was affected by the salinity and the effect increased with more stress at 100 mM of NaCl. Besides the response of C. schoenanthus to the salt stress, this study has allowed us to conclude that this plant is excluder glycophyte and less tolerant to salt stress.Key words: Cymbopogon schoenanthus, NaCl, growth, mineral nutrition, osmotic adjustment

Screening of the antimicrobial properties of the essential oils of Cymbopogon schoenanthus

Objective: The present study describes antimicrobial activity of the essential oil of Cymbopogon schoenanthus.Methods: The antimicrobial activity of the oil was evaluated using agar diffusion.Results: The antimicrobial test results showed that the oils had a great potential antimicrobial activity against all 13 bacteria: Bacillus cereus, B. subtilis, Enterococcus faecium, E. faecalis, Listeria monocytogenes, Staphylococcus aureus, Aeromonas hydrophila, Escherichia coli, E. coli O157:H7, Klebsiella pneumonia, Pseudomonas aeruginosa, Proteus mirabilis and Salmonella typhimurium.Conclusion: Results from this study suggest that the essential oil of Cymbopogon schoenanthus possesses antimicrobial properties, and is therefore may be a potential source of antimicrobial ingredients for the food and pharmaceutical industry

Anti-Inflammatory Potential of Compounds Isolated from Tunisian Lichens Species

The lichen's special symbiotic structure enables it to produce bioactive substances. They have historically been recognized for their aesthetic and medicinal benefits. Furthermore, in recent years, they have performed in various fields, including perfumery, dyeing, and pharmacology due to their rich secondary metabolites. From our study, four compounds were isolated from organic extracts of Parmotrema hypoleucinum, Roccella phycopsis, and Xanthoria parietina and identified by spectroscopic investigation as atranorin, (+)-iso-usnic acid, methyl orsellinate, and parietin, respectively. The anti-inflammatory effects of lichens extracts, and pure compounds were evaluated on RAW 264.7 macrophages cells at different concentrations. At 25 μg/mL all treated samples did not show any effect on cell viability. Atranorin and (+)-iso-usnic acid showed an inhibitory effect on nitric oxide (NO) levels in lipopolysaccharide (LPS)-stimulated macrophages. Nitric oxide (NO) production was measured using Griess reagent, atranorin and (+)-iso-usnic acid showed a high anti-inflammatory potential (75.99 % and 57.27 % at 25 μg/mL). On the other hand, methyl orsellinate and the organic extracts of three lichens showed good anti-inflammatory activity ranging from 29.16 % at 25 μg/mL to 86.91 % at 100 μg/mL

beta-caryophyllene emitted from a transgenic Arabidopsis or chemical dispenser repels Diaphorina citri, vector of Candidatus Liberibacters

[EN] Production of citrus, the main fruit tree crop worldwide, is severely threatened by Huanglongbing (HLB), for which as yet a cure is not available. Spread of this bacterial disease in America and Asia is intimately connected with dispersal and feeding of the insect vector Diaphorina citri, oligophagous on rutaceous host plants. Effective control of this psyllid is an important component in successful HLB management programs. Volatiles released from the non-host guava have been shown to be repellent to the psyllid and to inhibit its response to citrus odour. By analysing VOC emission from guava we identified one volatile compound, (E)-ß-caryophyllene, which at certain doses exerts a repellent effect on D. citri. Non-host plant rejection mediated by (E)-ß-caryophyllene is demonstrated here by using Arabidopsis over-expression and knock-out lines. For the first time, results indicate that genetically engineered Arabidopsis plants with modified emission of VOCs can alter the behaviour of D. citri. This study shows that transgenic plants with an inherent ability to release (E)-ß-caryophyllene can potentially be used in new protection strategies of citrus trees against HLB.We thank Dr. Pedro Serra (IBMCP, Valencia, Spain) for his help with statistical analysis, and Prof. Dr. Luiz A.B. de Moraes (Chemistry Department, FFCLRP, USP, Riberao Preto, Brazil) and Prof. Dr. Edson Rodrigues Filho (LaBioMMi, Chemistry Department, UFSCar, Sao Carlos, Brazil) for the use of GC-MS equipment. Use of the Citrus Germplasm Bank (IVIA, Valencia, Spain) is gratefully acknowledged. This work was funded by the Fundo de Defesa da Citricultura (Fundecitrus) and FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo, 2015/0711-3). 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