Potentiation of antibiotic activity of aminoglycosides by natural products from Cordia verbenacea DC.

Medicinal plants are often the only therapeutic resource for many communities and ethnic groups. Cordia verbenacea DC., "Erva-baleeira," is one of the species of plants currently used to produce a phytotherapeutic product extracted from its leaves. The present study aimed to establish its chemical profile, antibacterial activity and resistance-modulating potential. The C. verbenacea extracts were prepared from fresh leaves using solvents as methanol and hexane. Ethyl Acetate was used for the preparation of the fraction. Phytochemical screening was carried out using HPLC-DAD for determination and quantification of the secondary metabolites present in the fractions. Antibacterial and resistance-modulation assays were performed to determine minimum inhibitory concentration (MIC) using a microdilution assay. The data were subjected to statistical analysis with two-way ANOVA and Bonferroni posttests. Results of phytochemical prospecting and HPLC analysis of the fractions were in agreement with the literature. The natural products presented moderate antibacterial activity when considering the clinical relevance of a MIC of 256 µg/mL against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, and 512 µg/mL against P. aeruginosa. However, when the fractions were combined with antibiotics we observed a synergic effect, as natural products enhanced the antibacterial effect of aminoglycosides, significantly decreasing the MIC of antibiotics at 12.5%-98.4%. We believe that the data obtained from phytochemical analysis and from antibacterial and resistance modulation assays of C. verbenacea extracts new can open perspectives in the search for new alternatives for the treatment of bacterial infections and stimulate the renewed use of antibiotics with reduced effectiveness due to resistance.

Ethnopharmacological study of plants sold for therapeutic purposes in public markets in Northeast Brazil.

ETHNOPHARMACOLOGICAL RELEVANCE: Studies of ethnobiological nature favor the rescue of popular culture, preventing important cultural and biological information from being lost over time. Another interesting point is that it can support bioprospecting studies focusing on the discovery of new drugs. OBJECTIVE OF THE STUDY: Our aim was to conduct a survey of plants sold for therapeutic purposes in public markets in the Crajubar Triangle in Northeast Brazil. MATERIALS AND METHODS: Using a questionnaire, data were collected regarding the part of the plant used, method of preparation, quantity needed, instructions for use and known adverse effects. From the data obtained, we calculated the relative importance of species and informant consensus factor. RESULTS: Vendors indicated 91 useful species from a therapeutic point of view, distributed in 49 plant families. The preparation methods most frequently mentioned by informants were decoction, infusion, sauce with part of the plant in water and lozenge. The informants of this study mentioned bark, leaves, seeds and roots as parts of the plant most sold for therapeutic use. Disorders of the digestive system was the disease/disorder category with the highest consensus among the vendors, and the species Ximenia americana, Lippia gracillis, Stryphnodendron rotundifolium, Anacardium occidentale, Hymenaea courbail, Myracrodruon urundeuva, Amburana cearensis and Himatanthus drasticus were the most versatile among the plants sold in markets. CONCLUSIONS: Vendors indicated 91 species belonging to 49 botanical families and 89 genera. The most frequent forms of preparation were decoction, infusion and sauce made with part of the plant in water. The most common form of administration was oral. Bark and leaves were the plant parts most used. Thirteen species showed great versatility regarding their use. We noted 291 indications for use in 13 disease/disorder categories.

Ethnopharmacological study of Stryphnodendron rotundifolium in two communities in the semi-arid region of northeastern Brazil

This work describes the local knowledge of the medicinal use of Stryphnodendron rotundifolium Mart., Fabaceae, according to informants in two areas of the Araripe bioregion, in the Northeast Region of Brazil. We used interviews to investigate the ethnomedicinal use of the local species to determine the mode of use, frequency of administration, duration of treatment and restrictions of use. In traditional medicine, the use of S. rotundifolium is associated with the treatment of inflammatory and infectious diseases. The part of the plant most used was the stem bark (86.11%), the predominant mode of preparation was immersion in water (52.83%), and oral administration was the most cited (48.43%). For inflammatory and infectious diseases, the treatment lasted 3-10 days and the frequency of administration was 2-3 times/day. For gastroprotective effects, treatment lasted up to 30 days, and the herb was administered 1-3 times/day. For pain complaints, the therapy varied from 2-3 days to continuous administration.The informants (46.87%) did not mention restrictions of use, except for pregnant women, with a rate of 25%. A comparison of these results with the ethnopharmacological information from other studies showed that some of the traditional indications are scientifically supported by the literature or clinical studies. Nevertheless, the results showed that pharmacologists have not fully investigated all the possible bioactivities that healers credit to this plant. .

Chemical composition of the essential oil of Lippia gracilis Schauer leaves and its potential as modulator of bacterial resistance.

Lippia gracilis Schauer (Verbenaceae) is an aromatic plant widely used in folk medicine in the Brazilian semi-arid region. This work aims at evaluating the anti-microbial activity of essential oils from the leaves of L. gracilis (EOLG) when associated with commercial antibiotics against bacterial resistance. The essential oil obtained by hydrodistillation has 38 chemical constituents with thymol (44.4%), carvacrol (22.2%), p-cymene (6.2%) and α-pinene (5.6%) as major constituents. Microbiological assays were conducted by direct and gaseous contacts. We demonstrated that EOLG has significant synergism with all antibiotics tested. EOLG decreased the minimal inhibitory concentration of the aminoglycosides and improved their zone of inhibition more than 300% against Staphylococcus aureus and 270% against Pseudomonas aeruginosa. These results demonstrate that natural substances present in EOLG have the capacity to modulate bacterial resistance and can be used as an adjuvant therapy against multi-resistant microorganisms such as S. aureus, Escherichia coli and P. aeruginosa.

Phythochemical screening and antimicrobial activity phythochemical of essential oil from Lippia gracillis

The chemical composition of the essential oil obtained from the fresh and dried leaves of Lippia gracillis Schauer, Verbenaceae, was analyzed by gas chromatography and gas chromatography/mass spectrometry (GC⁄MS). The yield of essential oil extracted from the dried leaves was significantly higher (p<0.05) when compared to the fresh leaves. Seventeen components were identified. The monoterpenes and sesquiterpene hydrocarbons with 96.26 percent (w/w) of the total oil obtained of fresh leaves and 86.99 percent (w/w) of the total oil obtained of dried leaves were the principal compound groups. Thymol was observed dominant (44.42 percent; 21.3 percent), followed by carvacrol (22.21 percent; 21.30 percent), p-cymene (6.23 percent; 8.58 percent), α-pinene (5.65 percent; 19.42 percent), β-caryophyllene (5.61 percent; 3.57 percent) and other minor constitutes, respectively. Microbiological results obtained by agar diffusion method, micro dilution method and minimum inhibitory concentration (MIC) showed that the essential oil has a relevant antimicrobial activity against E. coli (ATCC 10536), E. coli (Ec 27), Pseudomonas aeruginosa (ATCC 15442), S. aureus (ATCC 12692) and S. aureus (Sa 358), with their inhibition zones ranging from 9 to 13 mm and the MIC ranging from 64 to 512 μg/mL.