Antibacterial Activity of the Essential Oil of Piper tuberculatum Jacq. Fruits against Multidrug-Resistant Strains: Inhibition of Efflux Pumps and ß-Lactamase.

Antimicrobial resistance has become a growing public health concern in recent decades, demanding a search for new effective treatments. Therefore, this study aimed to elucidate the phytochemical composition and evaluate the antibacterial activity of the essential oil obtained from the fruits of Piper tuberculatum Jacq. (EOPT) against strains carrying different mechanisms of antibiotic resistance. Phytochemical analysis was performed using gas chromatography-mass spectrometry (GC/MS). The antibacterial activity of EOPT and its ability to inhibit antibiotic resistance was evaluated through the broth microdilution method. The GC-MS analysis identified 99.59% of the constituents, with ß-pinene (31.51%), α-pinene (28.38%), and ß-cis-ocimene (20.22%) being identified as major constituents. The minimum inhibitory concentration (MIC) of EOPT was determined to assess its antibacterial activity against multidrug-resistant strains of Staphylococcus aureus (IS-58, 1199B, K2068, and K4100). The compound showed a MIC of ≥ 1024 µg/mL, suggesting a lack of intrinsic antibacterial activity. However, when the EOPT was associated with antibiotics and EtBr, a significant decrease in antibiotic resistance was observed, indicating the modulation of efflux pump activity. This evidence was corroborated with the observation of increased fluorescent light emission by the bacterial strains, indicating the involvement of the NorA and MepA efflux pumps. Additionally, the significant potentiation of ampicillin activity against the S. aureus strain K4414 suggests the ß-lactamase inhibitory activity of EOPT. These results suggest that the essential oil from P. tuberculatum fruits has antibiotic-enhancing properties, with a mechanism involving the inhibition of efflux pumps and ß-lactamase in MDR S. aureus strains. These findings provide new perspectives on the potential use of EOPT against antibiotic resistance and highlight the importance of Piper species as sources of bioactive compounds with promising therapeutic activities against MDR bacteria. Nevertheless, further preclinical (in vivo) studies remain necessary to confirm these in vitro-observed results.

Antibacterial Activity and Anxiolytic Effect in Adult Zebrafish of Genus Lippia L. Species.

Species belonging to the genus Lippia are used worldwide as foods, beverages, and seasonings. Studies have demonstrated that these species have antioxidant, sedative, analgesic, anti-inflammatory, and antipyretic activities. This work aimed to evaluate the antibacterial activity and anxiolytic effect by different pathways of essential oils and ethanolic extracts of three species of Lippia (Lippia alba, Lippia sidoides, and Lippia gracilis). The ethanolic extracts were characterized by HPLC-DAD-ESI-MSn and their phenolics were quantified. The antibacterial activity was evaluated by determining the minimal inhibitory concentration and modulation of antibiotic activity, and toxic and anxiolytic effects were evaluated in the zebrafish model. The extracts showed compositions with a low ratio and shared compounds. L. alba and L. gracilis showed higher amounts of phenols and flavonoids, respectively. All extracts and essential oils presented antibacterial activity, especially those obtained from L. sidoides. On the other hand, L. alba extract presented the most significant antibiotic-enhancing effect. The samples were not toxic after 96 h of exposure, but showed an anxiolytic effect through modulation of the GABAA receptor, while L. alba extract acted via modulation of the 5-HT receptor. This new pharmacological evidence opens horizons for therapeutic approaches targeting anxiolytic and antibacterial therapies and food conservation using these species and their constituents.

Chemical composition variation of essential oils of Copaifera langsdorffii Desf. from different vegetational formations.

This study aims to provide information about the chemical profile of the essential oil from C. langsdorffii resin in areas of Cerradão, Carrasco, and Humid Forest. In order to obtain the essential oils, oil-resin was submitted to hydrodistillation process, and the chemical components were analyzed by gas chromatography coupled to mass spectrometry (GC/MS). Twenty-six constituents were identified in the essential oil of C. langsdorffii resin, of which 12 were present in Cerradão, 15 in Carrasco and 18 in Humid Forest, with ß-bisabolene, caryophyllene oxide, γ-muurolene, α-caryophyllene and ß-caryophyllene common to the three phytophysiognomies. Among the studied areas, the resin collection varied from 2.652 g to 20.263 g, while the essential oil yield varied from 2.216 % to 11.764 %. A concentration range of 0.60 % to 84.57 % was recorded among the compounds in the three study areas. There was variation in chemical composition both among phytophysiognomies and among individuals from the same location, where ß-caryophyllene showed to be the majority for all areas studied, being present in all individuals from Cerradão, Carrasco and Humid Forest.

Chemical Profile and Evaluation of the Antioxidant and Anti-Acetylcholinesterase Activities of Annona squamosa L. (Annonaceae) Extracts.

This study presents the chemical profile of extracts from the pulp and seed of Annona squamosa L., as well as the evaluation of their antioxidant and acetylcholinesterase inhibition activities. In the chemical prospection, qualitative assays were performed, and the contents of total phenols, flavonoids, vitamin C, and carotenoids were quantified. For the compounds identification, analyses of the extracts were performed by liquid chromatography coupled to mass spectrometry. Antioxidant evaluation was performed using the DPPH, ABTS, Fe3+ reduction, 2-DR protection, and ß-carotene protection methods. The assay for inhibition of acetylcholinesterase activity was determined using the method described by Ellman. The secondary metabolites identified were anthocyanidins, flavones, flavonols, and alkaloids. Phenol analysis showed a higher quantitative value of total phenols and flavonoids for the seed extract, and the vitamin C content was higher in the pulp extract. There was no significant difference in relation to the carotenoids quantification. The best results obtained for antioxidant activity, for both seed and pulp extracts, were with the ABTS method with IC50 of 0.14 ± 0.02 and 0.38 ± 0.02 mg/mL, respectively. Compared to A. squamosa seed extract, the pulp extract demonstrates higher AChE inhibitory activity with IC50 of 18.82 ± 0.17 µg/mL. A. squamosa is a nutritious food source. The continuity of the studies is fundamental to relate the consumption of this food and its effects on neurodegenerative diseases.

Caracterización química y evaluación de las propiedades antioxidantes y antimicrobianas del aceite de pulpa de frutas de Mauritia flexuosa L. f. / Chemical characterization and evaluation of antioxidant and antimicrobial properties of the pulp oil of fruits of Mauritia flexuosa L. f

Este estudio tuvo como objetivo caracterizar las propiedades químicas, antioxidantes y antimicrobianas del aceite de pulpa de Mauritia flexuosa L. f. (Arecaceae). La identificación química se realizó por cromatografía de gases acoplada a espectrometría de masas. Se caracterizaron las propiedades fisicoquímicas. La capacidad antioxidante se ha verificado eliminando los radicales libres, reduciendo y quelando el hierro. La actividad antimicrobiana se evaluó mediante la concentración inhibitoria mínima y la acción moduladora de los antibióticos. Los principales ácidos grasos identificados fueron ácido esteárico, ácido palmítico y ácido oleico. La acidez y el índice de saponificación están dentro de los límites establecidos por la Agencia Nacional de Vigilancia Sanitaria. El aceite mostró actividad antioxidante moderada y actividad antimicrobiana contra las cepas de Candida. También mostró efectos sinérgicos, especialmente acerca de cefotaxima contra Bacillus cereus. Los resultados sugieren el potencial de la especie como antioxidante y en terapia antimicrobiana.

This study aimed to characterize the chemical, antioxidant and antimicrobial properties of the pulp oil of Mauritia flexuosa L. f. (Arecaceae). Chemical identification was performed by gas chromatography coupled to mass spectrometry. The physicochemical properties were characterized. Antioxidant capacity has been verified by eliminating of free radicals, reducing and chelation of iron. The antimicrobial activity was evaluated by the minimum inhibitory concentration and the modulatory action of antibiotics. The major fatty acids identified were stearic acid, palmitic acid and oleic acid. The acidity and the saponification index are within the limits established by the National Sanitary Surveillance Agency. The oil showed moderate antioxidant activity and antimicrobial activity against Candida strains. It also showed synergistic effects, especially on cefotaxime against Bacillus cereus. The results suggest the potential of the species as an antioxidant and in antimicrobial therapy.

Chemical analysis and evaluation of antioxidant and antimicrobial activities of fruit fractions of Mauritia flexuosa L. f. (Arecaceae).

BACKGROUND: Fruit consumption is currently considered beyond the nutritional aspects because of the important roles in disease prevention and benefits to health. The objective of this study was to characterize the chemical profile and evaluate the antioxidant and antimicrobial properties of different fractions obtained from fruit pulps of Mauritia flexuosa (MFFs). METHODS: Initially, chloroform, ethyl acetate and ethanol fractions were obtained from the pulps. Quantifications of total phenols and flavonoids were performed using the methods of Folin-Ciocalteu and complexation with aluminum chloride, respectively. Standard samples were used to identify and quantify phenolic acids and flavonoids using high-performance liquid chromatography with a diode-array detector (HPLC-DAD). The antioxidant capacity of the fractions was verified by sequestration of the free radical 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS) and iron chelating activity. The antimicrobial activity was determined using the microdilution method and the modulating activity was determined using sub-inhibitory concentrations of the fractions in association with antibiotics. RESULTS: The chemical analyzes revealed the presence of catechin, caffeic acid, rutin, orientin, quercetin, apigenin, luteolin and kaempferol, where all are present in the ethyl acetate fraction. The fractions exhibited moderate antioxidant and antimicrobial activities against Gram-positive and Candida strains in addition to modulating the activity of conventional antibiotics. The most expressive result was obtained from the association of the chloroform fraction with cefotaxime, which produced a synergistic effect, reducing the minimum inhibitory concentration (MIC) of the antibiotic from 1,024 to 256 µg/mL. DISCUSSION: The fractions presented a constitution rich in phenolic compounds, especially flavonoids. The data obtained demonstrated that the fractions presented moderate antioxidant activity by acting both as primary and secondary antioxidants. The fractions presented antimicrobial and antibiotic potentiating activities, being the first record of modulating effect of fractions of this species against the studied microbial strains, but failed in modulating the activity of antifungal drugs, indicating that this plant has the potential to be used in the development of therapeutic alternatives against resistant bacteria. The constitution phenolic the fractions may be responsible for their pharmacological properties in vitro.

In vitro antimicrobial activity of the essential oil from Vanillosmopsis arborea Barker (Asteraceae) and its major constituent, α-bisabolol.

Vanillosmopsis arborea Barker (Asteraceae), commonly known as "candeeiro" is an endemic tree to the Caatinga biome, in northeast Brazil. The major component of its essential oil is α-bisabolol, a monocyclic sesquiterpene alcohol with several biological activities reported. In this study, the antimicrobial activity of the essential oil of V. arborea was investigated in comparison with its major component α-bisabol. The antimicrobial activity was performed against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 12692, Candida albicans (CA) INCQS 40006, Candida krusei (CK) INCQS 40095, Candida tropicalis (CT) INCQS 40042, and multiresistant bacterial strains Staphylococcus aureus 03 and Escherichia coli 08 by the microdilution method and direct contact modulation. The results showed that all strains were sensitive to the samples, except E. coli against the essential oil. Both the essential oil and the α-bisabolol had a synergistic effect against all strains, except for ampicillin against S. aureus 03, which did not show any modifications when combined with the oil. These data show the potential of V. arborea essential oil as an antibiotic modulator as well as a source of bioactive compounds with potential for the development of antimicrobial drugs as well as adjuvant to therapy against these pathogens.

Development and validation of a rapid RP-HPLC-DAD analysis method for the quantification of pilocarpine in Pilocarpus microphyllus (Rutaceae).

A method using high performance liquid chromatography with diode array detector (HPLC-DAD) for identification and quantification of pilocarpine in the extract of Pilocarpus microphyllus, popularly known as jaborandi. The analysis was conducted using RP-18 column (250 mm × 4.6 mm x 5 µm id) and a buffer solution composed of acidified water, phosphoric acid and triethylamine and methanol as a mobile phase in a flow rate of 1.0 mL/min and detection at 215  nm at 25 °C. Excellent linearity with r2 equal to 0.9999 was obtained. The recovery percentage was very satisfactory with values within the specifications. It is correct to affirm that the method has optimal intracurrent and intercurrent precision values with relative standard deviations of 0.1852% and 0.1932%, respectively. The robustness of the method, assessed through the Youden test, showed no significant influence of any of the evaluated parameters. In general, the method proved to be suitable for the intended purpose.