Which tree orders in southern Africa have the highest antimicrobial activity and selectivity against bacterial and fungal pathogens of animals?

BMC Complementary and Alternative Medicine

Research Article

Jacobus Nicolaas Eloff¹  Elisabeth Pauw¹ 

[1] Phytomedicine Programme, Department Paraclinical Sciences, Faculty Veterinary Science, University of Pretoria, Private Bag X04, 0110, Onderstepoort, South Africa;

关键词: Tree Species;    Antimicrobial Activity;    Minimum Inhibitory Concentration;    Little Square Mean;    High Antimicrobial Activity;   

DOI  :  10.1186/1472-6882-14-317

 received in 2014-04-07, accepted in 2014-08-05,  发布年份 2014

来源: Springer

【 摘 要 】

BackgroundThe study randomly screened leaf extracts of several hundred southern African tree species against important microbial pathogens to determine which taxa have the highest activity and may yield useful products to treat infections in the animal health market.MethodsWe determined the antibacterial and antifungal activity of 714 acetone leaf extracts of 537 different tree species against Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Cryptococcus neoformans. A sensitive serial dilution microplate method was used.ResultsSeveral extracts had MICs as low as 0.02 mg/ml. We analysed 14 out of the 38 tree orders where we determined the activity of more than 8 different tree species representing 89% of all species examined. There were statistically significant differences in some cases. Celastrales, Rosales and Myrtales had the highest activity against Gram-positive bacteria, the Myrtales and Fabales against the Gram-negative bacteria and the Malvales and Proteales against the fungi. Species present in the Asterales followed by the Gentiales and Lamiales had the lowest activities against all the microorganisms tested. Fabales species had the highest activities against all the microorganisms tested. There was substantial selectivity in some orders. Proteales species had very high activity against the fungi but very low activity against the bacteria. The species in the Celastrales and Rosales had very low antifungal activity, low activity against Gram-negative bacteria and very high activity against Gram-positive bacteria.ConclusionAgainst all classes of microorganisms, the four orders containing species with the highest average antimicrobial activities also contained several species with low activities against different pathogens and vice versa. These results therefore should be used with circumspection in selecting tree orders that would yield the highest probability of finding species with promising activities. Nevertheless there was a twofold increase in probability of finding extracts with interesting antifungal activity from orders with high mean activity than from orders with low mean activity. The probability increased to threefold and fivefold for Gram-positive and Gram-negative bacteria respectively.

【 授权许可】

CC BY   
© Pauw and Eloff; licensee BioMed Central Ltd. 2014