Molecular Docking and GC/MS-Based Approach for Identification of Anxiolytic Alkaloids from Griffinia (Amaryllidaceae) Species in a Zebrafish Model.

Griffinia gardneriana Ravenna, Griffinia liboniana Morren and Griffinia nocturna Ravenna (Amarillydaceae) are bulbous plants found in tropical regions of Brazil. Our work aimed to determine the alkaloid profiles of Griffinia spp. and evaluate their anxiolytic potential through in vivo and in silico assays. The plants grown in greenhouses were dried and their ground bulbs were subjected to liquid-liquid partitions, resulting in alkaloid fractions that were analyzed by gas chromatography coupled to mass spectrometry (GC-MS). Anxiolytic activity was evaluated in zebrafish (Danio rerio) through intraperitoneal injection at doses of 40, 100 and 200 mg/kg in light-dark box test. GC-MS analyses revealed 23 alkaloids belonging to different skeleton types: lycorine, homolychorine, galanthamine, crinine, haemanthamine, montanine and narcisclasine. The chemical profiles were relatively similar, presenting 8 alkaloids common to the three species. The major component for G. gardneriana and G. liboniana was lycorine, while G. nocturna consisted mainly of anhydrolycorine. All three alkaloid fractions demonstrated anxiolytic effect. Furthermore, pre-treatment with diazepam and pizotifen drugs was able to reverse the anxiolytic action, indicating involving the GABAergic and serotonergic receptors. Molecular docking showed that the compounds vittatine, lycorine and 11,12-dehydro-2-methoxyassoanine had high affinity with both receptors, suggesting them to be responsible for the anxiolytic effect.

In vitro anthelmintic activity of Lippia alba essential oil chemotypes against Haemonchus contortus.

The aim of the present study was to evaluate the effects of the essential oils of Lippia alba chemotypes carvone and citral on H. contortus. Chemical characterization was performed by means of gas chromatography coupled to mass spectrometry (GC/MS). The anthelmintic effects of the essential oils were assessed through the egg hatch test (EHT) and the adult worm motility test (AWMT) using a multidrug-resistant H. contortus Kokstad isolate. Confocal laser scanning microscopy (CLSM) of eggs and adults of H. contortus and scanning electron microscopy (SEM) of adults were performed after treatment with oils for qualitative observations of their effects. The carvone chemotype of L. alba (LaCV) presented 70% carvone, and the citral chemotype of L. alba (LaCT) presented 29.4% geranial and 20.4% neral, respectively. In the EHT, the EC50 values of LaCV and LaCT were 0.2 and 0.3 mg/mL, respectively. In AWMT, after 12 h of exposure to 2 mg/mL LaCV and 2 mg/mL LaCT, 100% of adult nematodes were immobile. CLSM showed changes in larval motility inside the egg caused by LaCV, while LaCT promoted changes in larval formation. In adults exposed to both chemotypes, alterations in the anterior portion of the oesophagus were observed. In SEM, morphological changes were observed in the buccal capsule and in the medial portion of H. contortus adults. It is concluded that the two essential oils of L. alba, the chemotypes carvone and citral, caused morphological changes and inhibited the hatching of eggs and the motility of adult H. contortus nematodes.

The antimicrobial efficacy of Lippia alba essential oil and its interaction with food ingredients.

The objective of this study was to evaluate the antimicrobial potential of Lippia alba essential oil (EOLa) and to investigate the effect of food ingredients on its efficacy. The antimicrobial potential of the oil was determined by the presence or absence of inhibition zones, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against Escherichia coli, Listeria innocua, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella choleraesuis and Staphylococcus aureus. The effect of food ingredients and the pH on the antimicrobial efficacy of oil was assessed by monitoring the maximum growth rate of Listeria monocytogenes in model media. The model media included potato starch (0, 1, 5 or 10%), beef extract (1, 5, 3, 6 or 12%), sunflower oil (0, 5 or 10%) and TSB broth at pH levels of 4, 5, 6 or 7. The EOLa showed efficacy at all concentrations (50%, 25%, 6.25%, 3%, 1.5%, 0.8%, 0.4% and 0.2%) evaluated, against all bacterial species, Gram-positive and Gram-negative. The antimicrobial efficacy of EO was found to be a function of ingredient manipulation. Proteins and lipids had a negative impact on the oil effectiveness, indicating the protective action of both on the microbial specie tested. On the contrary, at the highest concentration of starch (10%), the lower rate growth of L. monocytogenes was detected, therefore indicating a positive effect of carbohydrates on the oil effectivenes. Regarding the pH, the studies showed that the rate of microbial growth increased with increasing pH. It was concluded that the use of EOLa is more effective control pathogenic and spoilage bacteria when applied to starchy foods under an acidic pH.