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Ethnopharmacological relevance The use of popular plants has guided pharmaceutical research aimed at combating pathogenic microorganisms. Psidium guajava L. is a plant of great versatility and it has been used both as food and as a therapeutic agent. Root, bark, leaves, fruits, flowers and seeds are used for medicinal purposes, especially in infusions and decoctions for oral and topical use . P. guajava is utilized in symptomatology treatment related to organ malfunction and of diseases caused by the action of pathogenic and/or opportunistic microorganisms. Many pharmacological studies have been conducted to scientifically assess its therapeutic potential. Aims of study The aim of the current study is to relate the popular use of this plant and its bioscientific assessment as a therapeutic agent in the treatment of diseases and symptoms caused by the action of protozoa, fungi, bacteria and viruses, and also evaluate the safety for the usage and the interaction with drugs. Materials and methods A bibliographic database the ethnobiology of Psidium guajava (2005–2015) and the pharmacological infections and parasitic diseases (2010–2015). Searches were done in scientific disclosure databases such as PubMed, Web of Science, and Scopus. Results P. guajava leaf extracts were scientifically investigated for the treatment of diseases caused by protozoa (leishmaniasis, malaria, giardiasis, amoebiasis and trichomoniasis), fungi (dermatosis, systemic and mucocutaneous diseases), bacteria (respiratory, mucocutaneous and gastrointestinal infections, cholera, gastritis and stomach ulcers, oral and periodontal infections, venereal diseases and urinary infections) and viruses (herpes, influenza, rotavirus disease and AIDS). The toxicity assays indicates the safet for usage. Conclusions Highlight and elucidate the therapeutic potential and versatility of P. guajava . They also justify using ethnobiology efficiency to guide pharmacological studies. Some limitations can be observed in this kind of study, as the lack for ethnobiological informations and the absence of some controls in the assays.

The Piper mikanianum species were investigated by the antimicrobial potential and chemical composition. Chemical analysis was performed by gas chromatography coupled to mass spectrometry (GC/MS). The Minimum Inhibitory Concentration (MIC) as well as the 50% Inhibitory Concentration against Candida strains were determined by microdilution. The effect of the drug-oil combination was also evaluated to verify possible synergism. The Minimum Fungicidal Concentration (MFC) was evaluated by subculturing the microdilution in Petri dishes and the anti-pleomorphism potential of the oil was tested in humid chambers. Chemical analysis revealed safrol as the major compound. The results from the intrinsic activity evaluation of the oil did not reveal a clinical importance, however, it presented a synergistic effect when associated with gentamicin against the multidrug resistant E. coli strain and when associated with fluconazole against fungal strains. Moreover, the oil possessed a fungistatic effect. Total inhibition of filamentous structures occurred in both Candida species in the anti-virulence test. The P. mikanianum essential oil showed a potentiating activity of drugs for which resistance exists and an inhibitory effect of one of the main virulence factors of the Candida genus, morphological transition, which has been previously shown to be responsible for causing invasive infections in human tissues.

The aim of this study was to evaluate the chemical profile and antioxidant, antimicrobial and antiparasitic activities of the hydroalcoholic extract of the leaves of Ziziphus joazeiro Mart. (HELZJ). The antioxidant DPPH and FRAP assays and chemical profile were determined by colorimetric methods and HPLC/DAD. The antiparasitic, antibiotic and antibiotic-modifying activity were evaluated by microdilution assays. The HPLC–DAD assay showed the presence of mostly tannins and flavonoids, such as caffeic acid and quercetin. The levels of polyphenols and flavonoids were 183.136mg/g extract and 7.37mg/g extract, respectively. DPPH and FRAP showed low antioxidant activity for the extract. The antibacterial and antifungal activities were not of clinical relevance, showing MIC>1024μg/mL. However, synergism was observed between HELZJ and the antibiotics amikacin and gentamicin, which resulted in decreased bacterial drug resistance. EHFZJ showed low toxicity in fibroblasts in vitro, while antiparasitic results against Trypnosoma cruzi, Leishmania braziliensis and Leishmania infantum were not clinically relevant. Thus, our results indicate that Z. joazeiro Mart. (HELZJ) could be a source of plant-derived natural products that could lead to the development of promising new antibiotic compounds for infectious diseases.

Introduction “Erva-baleeira,” Cordia verbenacea DC. (Boraginaceae), is one of the species of plants currently exploited for the purpose of producing a phytotherapeutic product, which is extracted from the leaves. Methods Extracts of C. verbenacea were prepared from fresh leaves, and chloroform fractions were obtained from the different extracts for evaluation. Phytochemical screening was performed and the phytochemicals were quantified by HPLC-DAD. The microdilution assay was used to determine antibiotic and aminoglycoside-modifying activities (2.4–2500 μg/mL), and the results were analyzed using two-way ANOVA and Bonferroni post-test. Results Phytochemical screening and HPLC analysis of the fractions were in agreement with the literature, which describes the presence of several tannins and flavonoids in C. verbenacea leaves. The fractions showed moderate antibacterial activity when considering clinical relevance with a MIC of 128 μg/mL against a resistant strain of Staphylococcus aureus and 512 μg/mL against a resistant strain of Pseudomonas aeruginosa. However, when they were combined with antibiotics, synergism was observed, significantly lowering the MIC of the antibiotics by 12.5 (P Conclusions Our results indicated that the fractions of C. verbenacea, when combined with an antibiotic, demonstrated significant synergistic activity. Due the extensive use and sale of products derived from C. verbenacea may exert pressure on the populations of this species. The development of management plans for rational and sustainable use of the species and more studies with emphasis on the use of such fractions in the treatment of other diseases are necessary.

Introduction The objective of this study was to evaluate the antibacterial activity of methanol (MFEECC) and ethyl acetate (AFEECC) fractions, obtained from the ethanol extract of Croton campestris A. leaves. Methods Antibacterial and modulating activity (on bacterial resistance) was determined by micro dilution method to identify the MIC (Minimum Inhibitory Concentration), performed in triplicate and statistical significance tested by ANOVA (two-way) with Bonferroni post hoc test ( p Results In the antibacterial activity tests the fractions showed a MIC of ≥1024 μg/mL. In regards to modulation of bacterial resistance, MFEECC showed synergism when combined with antibiotic against bacterial strains. In the modulation tests, AFEECC potentiated the effects of amikacin against Staphylococcus aureus and Pseudomonas aeruginosa but had an antagonistic effect against Escherichia coli . AFEECC combined with gentamicin displayed antagonism against S. aureus and E. coli and an antagonistic effect against P. aeruginosa. When AFEECC was combined with Neomycin it resulted in antagonism against P. aeruginosa but did not affect S. aureus and E. coli . Conclusions The results indicate that the extracts and fractions obtained from C. campestris leaves could represent an alternative source of natural products capable of modifying and interfering with bacterial resistance to aminoglycosides.