Anti-infective, cytotoxic and antioxidant activity of Ziziphus oxyphylla and Cedrela serrata

Objective: To search for the most active antimicrobial and antioxidant sub-fractions related to traditional use of Ziziphus oxyphylla (Z. oxyphylla) and Cedrela serrata (C. serrata) in Pakistan against infectious and liver diseases. Methods: Factions of different polarity were tested in vitro for their antiprotozoal, antimalarial, antibacterial and antifungal activity against different pathogens. Cytotoxicity on MRC-5 cell lines (human lung fibroblasts) as well as, in vitro radical scavenging activity was evaluated using the 1, 1-diphenyl-2-picrylhydrazyl radical assay. Results: The highest antiprotozoal activity was observed for the CHCl3 fractions of Z. oxyphylla roots and leaves, and C. serrata bark. The CHCl3 and EtOAc fractions of Z. oxyphylla roots, the CHCl3 fraction of Z. oxyphylla leaves, the EtOAc and the residual MeOH: H2O fraction of C. serrata bark showed antibacterial activity against Staphylo-coccus aureus. The same residual MeOH: H2O fraction of C. serrata bark was active against Candida albicans. The highest antioxidant activity was observed for the more hydrophilic EtOAc fractions of Z. oxyphylla leaves, C. serrata bark and leaves, and the residual MeOH:H2O fraction of C. serrata bark. Conclusions: This study supports at least in part the traditional uses of these plants for antimicrobial purposes and against liver diseases.

In vitro antimicrobial assessment of Cuban propolis extracts

Propolis is a resinous mixture of different plant exudates collected by honeybees. Currently, propolis is widely used as a food supplement and in folk medicine. We have evaluated 20 Cuban propolis extracts of different chemical types, brown (BCP), red and yellow (YCP), with respect to their in vitro antibacterial, antifungal and antiprotozoal properties. The extracts inhibited the growth of Staphylococcus aureus and Trichophyton rubrum at low µg/mL concentrations, whereas they were not active against Escherichia coli and Candida albicans. The major activity of the extracts was found against the protozoa Leishmania, Trypanosoma and Plasmodium, although cytotoxicity against MRC-5 cells was also observed. The BCP-3, YCP-39 and YCP-60 extracts showed the highest activity against P. falciparum, with 50% of microbial growth (IC50) values of 0.2 µg/mL. A positive correlation between the biological activity and the chemical composition was observed for YCP extracts. The most promising antimicrobial activity corresponds to YCP subtype B, which contains acetyl triterpenes as the main constituents. The present in vitro study highlights the potential of propolis against protozoa, but further research is needed to increase selectivity towards the parasite. The observed chemical composition-activity relationship of propolis can contribute to the identification of the active principles and standardisation of this bee product.

In vitro anti-microbial activity of the Cuban medicinal plants Simarouba glauca DC, Melaleuca leucadendron L and Artemisia absinthium L

In the present study, an extensive in vitro antimicrobial profiling was performed for three medicinal plants grown in Cuba, namely Simarouba glauca, Melaleuca leucadendron and Artemisia absinthium. Ethanol extracts were tested for their antiprotozoal potential against Trypanosoma b. brucei, Trypanosoma cruzi, Leishmania infantum and Plasmodium falciparum. Antifungal activities were evaluated against Microsporum canis and Candida albicans whereas Escherichia coli and Staphylococcus aureus were used as test organisms for antibacterial activity. Cytotoxicity was assessed against human MRC-5 cells. Only M. leucadendron extract showed selective activity against microorganisms tested. Although S. glauca exhibited strong activity against all protozoa, it must be considered non-specific. The value of integrated evaluation of extracts with particular reference to selectivity is discussed.