José Galberto Martins da Costa

Enhancement of the Antibiotic Activity against a Multiresistant Escherichia coli by Mentha arvensis L. and Chlorpromazine

Background: This is the first report testing the antibiotic resistance-modifying activity of Mentha arvensis. Methods: In this study an ethanol extract of M. arvensis L. and chlorpromazine were tested for their antimicrobial activity alone or in combination with conventional antibiotics against strains of Escherichia coli. Results: The growth of two E. coli strains tested was not inhibited by the extract. The minimum inhibitory concentration and minimal bactericide concentration values were ≧1 mg/ml for both strains of E. coli used. A potentiating effect of this extract on gentamicin was demonstrated. Similarly, there was a potentiating effect of chlorpromazine on kanamycin, amikacin and tobramycin, indicating the involvement of an efflux system in the resistance to these aminoglycosides. Conclusions: It is therefore suggested that extracts from M. arvensis could be used as a source of plant-derived natural products with resistance-modifying activity, such as in the case of gentamicin, constituting a new weapon against bacterial resistance to antibiotics, as with chlorpromazine.

In vitro anti-staphylococcal activity of Hyptis martiusii Benth against methicillin-resistant Staphylococcus aureus: MRSA strains

This is the first report about the antibacterial activity of Hyptis martiusii Benth. In this study the ethanol extract of H. martiusii was tested for its antimicrobial activity against strains of Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The growth of all bacterial strains tested was inhibited by the extract. The diameter of inhibition zones varied from 13 to 20 mm for the extract. The MIC and MBC values ranged from 128 to > 1024mg/mL and 256 to > 1024 mg/mL, respectively. It is therefore suggested that extracts from H. martiusii could be used as an anti-Staphylococcus agent. Compared with methicillin and gentamicin, the extract was more effective, being a promising antibacterial agent.

Synergistic antibiotic activity of volatile compounds from the essential oil of Lippia sidoides and thymol

Lippia sidoides Cham. (Verbenaceae) is used in the folk medicine as topical antiseptic in skin and mucous membranes and its therapeutic effect is attributed to the thymol presence. The objective of this work was to verify the chemical composition and antibiotic modifying activity of the essential oil extracted from the leaves of L. sidoides and its major component thymol. The essential oil was obtained by hydrodistillation and analyzed by GC/MS. The synergistic activity was evaluated using gaseous contact method. The essential oil was obtained (yield of 1.06%) and the GC/MS analysis identified the main constituents: thymol (84.9%) and p-cymene (5.33%). The antibiotic modifying activity was verified using the minimal inhibitory dose method and gaseous contact. It verified the interference of essential oil and thymol against all tested aminoglycosides. There were no statistical differences between the activity of the essential oil and thymol against Pseudomonas aeruginosa, indicating this to be the responsible composition for such activity. However, the oil was shown more effective when compared to the thymol against Staphylococcus aureus. The essential oil of L. sidoides and its major component thymol influence the activity of aminoglycosides and may be used as adjuvant in antibiotic therapy against respiratory tract bacterial pathogens.

Synergy effects of the antibiotics gentamicin and the essential oil of Croton zehntneri

The leaves of Croton zehntneri Pax et Hoffm (Euphorbiaceae) were subjected to hydrodistillation, and the essential oil extracted was examined with respect to antibacterial and antibiotic modifying activity by gaseous contact. The gaseous component of the oil inhibited the bacterial growth of Staphylococcus aureus and Pseudomonas aeruginosa with a MID of 0.5 and<1mg/l air, respectively. The activity of the antibiotic gentamicin was increased by 42,8% against P. aeruginosa after contact with the gaseous component, showing that this oil influences the activity of the antibiotic and may be used as an adjuvant in the antibiotic therapy of respiratory tract bacterial pathogens.

Topical anti-inflammatory effect of Caryocar coriaceum Wittm. (Caryocaraceae) fruit pulp fixed oil on mice ear edema induced by different irritant agents

AIM OF THE STUDY Caryocar coriaceum Wittm. fruit pulp fixed oil (CCFO) has been widely employed by communities from Brazil Northeastern in the treatment of skin inflammation, respiratory affections, wound healing and muscle pain. In this study, we evaluated the topical effect of CCFO against different irritant agents in vivo, in order to verify its antiedematous effect as well to unravel its tentative mechanisms of action. MATERIALS AND METHODS CCFO was obtained from Caryocar coriaceum fruits using ethyl acetate as solvent. Ear edema provoked by the application of Croton oil (single and multiple applications), arachidonic acid (AA), capsaicin, phenol and histamine to Swiss mice was used to evaluate the topical anti-inflammatory effect of CCFO. Histological analysis from mice ears sensitized with Croton oil and AA single application was also performed. RESULTS Crude CCFO (20μL/ear) demonstrated significant topical antiedematous effect against Croton oil single (inhibition of 32.0%; P<0.05) and multiple (41.4% after 9 days, P<0.001) applications, AA (inhibition of 49.7%; P<0.01) and phenol (inhibition of 38.8%; P<0.001). In contrast, CCFO did not antagonize the edema caused by topical treatment with capsaicin and histamine when compared to control group (P>0.05). Histological analysis also revealed that CCFO was able to reduce the edema and the influx of inflammatory cells in mice ears sensitized with Croton oil and AA. CONCLUSIONS CCFO exhibited a similar profile of topical anti-inflammatory activity to that of drugs that classically modulate the production of arachidonic acid metabolites. The study also indicates the potential application of CCFO as an important herbal medicine to be used against skin inflammatory diseases.

Estudo químico-biológico dos óleos essenciais de Hyptis martiusii, Lippia sidoides e Syzigium aromaticum frente às larvas do Aedes aegypti

The interest for a biological assay against larvae of Aedes aegypti and Culex quinquefasciatus is due to the fact that these species are distributed by the whole national territory, being therefore an activity carried out by countless researchers of Brazil. The essential oils of Syzigium aromaticum, Hyptis martiusii and Lippia sidoides were tested in the combat of the transmitter of the dengue and of the filariosis, using larvae of third stadium were exposed in triplicate to different concentrations (1000, 500, 250, 100, 50, 25 and 10 ppm). The larvicidal activity was observed after ten minutes of the beginning of the treatment, in the end showed very significant results, with mortality potentials of up to 100% of the tested larvae, indicating accentuated toxical effects in some representatives of the volatile compounds present in the oils. For the oils of S. aromaticum, L. sidoides and H. martiusii DL50 of 1,0; 1,0 and 8,0 ppm, respectively, were observed.

Antibacterial and Antioxidant Activities of Ursolic Acid and Derivatives

Ursolic acid, an important bioactive compound, was isolated from ethanol extract of aerial parts of Sambucus australis. In order to develop bioactive ursolic acid derivatives, two semi-synthetic compounds were obtained through modification at C-3. The antibacterial activity of the ursolic acid and its derivatives was investigated. The microdilution method was used for determination of the minimal inhibitory concentration (MIC), against twelve bacterial strains. The influence of ursolic acid and its derivatives on the susceptibility of some bacterial pathogens to the aminoglycosides antibiotics neomycin, amikacin, kanamycin and gentamicin was evaluated. The most representative synergistic effect was observed by 3β-formyloxy-urs-12-en-28-oic acid at the concentration of 64 μg/mL in combination with kanamycin against Escherichia coli (27), a multidrug-resistant clinical isolate from sputum, with reduction of MIC value from 128 μg/mL to 8 μg/mL. Ursolic acid and its derivatives were examined for their radical scavenger activity using the DPPH assay, and showed significant activity.

(-)-α-Bisabolol attenuates visceral nociception and inflammation in mice.

The study examined the antiinflammatory and antinociceptive effects of the sesquiterpene (-)-α-bisabolol (BISA). The antiinflammatory effect was evaluated on acute models of dermatitis induced by Croton oil, arachidonic acid, phenol and capsaicin, respectively, in mouse ear. BISA inhibited the dermatitis induced by all noxious agents, except capsaicin. BISA was assessed in two established mouse models of visceral nociception. Mice were pretreated orally with BISA, and the pain-related behavioral responses to intraperitoneal cyclophosphamide or to intracolonic mustard oil were analyzed. BISA showed a dose-unrelated significant antinociception. Collectively, the results suggest that BISA may be an topical antiinflammatory and visceral antinociceptive agent.

Is the body fat of the lizard Tupinambis merianae effective against bacterial infections

AIM OF THE STUDY Tupinambis merianae is one of the animals that is most frequently used for medicinal purposes in Brazil as its body fat has many therapeutic indications in local folk medicine. This work presents the chemical compositions of the body fat of Tupinambis merianae and evaluates the antibacterial activity of the body fat as well as the ecological implications of its use in traditional medicine. MATERIALS AND METHODS Oil (OTM) was extracted from body fat located in the ventral region of Tupinambis merianae using hexane as a solvent. Fatty acids were determined indirectly using their corresponding methyl esters. The antibacterial activity of OTM was tested against standard as well as multi-resistant lines of Escherichia coli and Staphylococcus aureus, either alone or in combination with antibiotics and UV-A light. RESULTS Body fat of Tupinambis merianae presents 57% and 43% of unsaturated and saturated fatty acids respectively. Our results indicated that OTM did not demonstrate relevant antibacterial activity against any of the lines of Escherichia coli or Staphylococcus aureus, nor when combined with antibiotics or with UV-A light. CONCLUSIONS In light of these results, we recommend (i) development of management plans for a sustainable and rational use of Tupinambis merianae reducing the possible pressure on this species; and (ii) more studies be focused on the use of OTM and other natural products derived from animals that are used to treat other illnesses.

Effect of Momordica charantia L. in the resistance to aminoglycosides in methicilin-resistant Staphylococcus aureus

In this study the ethanol extract (EEMC) of Momordica charantia L. (Cucurbitaceae) was tested for its modifying antibiotic activity against a MRSA strain. The growth of an MRSA (SA358) in the absence and presence of aminoglycosides was evaluated. A potentiating effect between this extract and all aminoglycosides was demonstrated. Similarly, the same effect was shown by chlorpromazine on kanamycin, gentamicin and neomycin, indicating the involvement of an efflux system in the resistance to these aminoglycosides. Extracts from M. charantia could be used as a source of plant-derived natural products with resistance-modifying activity. This is the first report about the modifying antibiotic activity of M. charantia, constituting a new weapon against multi-resistant bacteria such as MRSA.