Antimicrobial activity of plant secondary metabolites: A review

The increasing incidence of microorganisms becoming resistant to antibiotics has continuously become a scientific community concern. Many scientists around the world are performing research on plants to be able to discover possible antimicrobial compounds. To date, many plant secondary compounds are known to have diverse biological activities. These may include antibacterial, antifungal and anticancer activities. In this regard, many scientists want to isolate, purify and identify plant secondary metabolites. The aim of this study is to provide recent insights on the different secondary metabolites class and the experimental evidences of antibacterial activities against many different pathogens. © 2014 Academic Journals Inc

Comparison and temperature study of lectin activities in Texas live oak (Quercus fusiformis) crude extracts

Lectins are proteins that contain at least one non-catalytic carbohydrate binding domain. In plants, these proteins are hypothesized to play a critical role in plant defense functions. The extant literature shows that lectins have diverse applications, including medicinal and therapeutic ones. This study examines the presence and the level of lectin activity in the Texas live oak (Quercus fusiformis Small), a plant native to and replete in the South Texas region. To detect and compare lectin activity among selected plant parts of Q. fusiformis, agglutination and protein assays were conducted. The influence of four factors on lectin activity was investigated. These factors are: plant part (leaf, stem and fruit), tree section (A, B and C), temperature (0, 50 and 100°C) and time duration (1, 2 and 3 h) at the different temperature levels. Analysis of variance (ANOVA) associated with a factorial experiment, mean comparisons by way of a Tukey\u27s test, trend analysis and regression analysis comprised the analytical strategy. Results indicated that lectin activity is present in each of the selected plant parts and varies significantly across these parts. ANOVA revealed that lectin activity is significantly linked to temperature level. Although relatively stable from 0 to 50°C, trend and regression analyses indicated significant linear and quadratic effects of temperature on lectin activity. These analyses indicated that maximum activity is predicted to occur at about 31°C. No interaction effect was detected between and among the four factors examined. © 2011 Academic Journals Inc

Evaluation of the antimicrobial activity of Zanthoxylum zanthoxyloides root bark extracts

The development of resistance to antibiotics by infectious agents has been a continuous challenge. Thus, in this study, the aim was to evaluate the antimicrobial activities of Zanthoxylum zanthoxyloides, a potential plant source for novel antibiotics. Toward this end, dried powdered samples of the root barks of Z. zanthoxyloides were extracted successively to obtain Crude Petroleum Ether (CPE), Defatted Ethanol Ether (DEE) and Defatted Ethanol Chloroform (DEC) extracts. The antimicrobial activities indicated by the size of the Zone of Inhibition (ZOI) of each extract at concentrations 5, 10, 15, 20 and 30 μg μL -1 were evaluated against Escherichia coli (E. coli), methicillin-susceptible Staphylococcus aureus (MSSA), Methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VREF) using disc diffusion method. Two sets of Analysis of Variance (ANOVA) were performed. The first set comprised separate ANOVAs for each microorganism because the positive controls were different for each microorganism, although the negative control (DMSO) was the same for all. The second set was a single combined ANOVA with all microorganisms included with their positive controls excluded. The first set of analysis showed that DEE had significantly (p\u3c0.001) higher antimicrobial activity than DMSO, CPE, or DEC. No significant interaction between extract and concentration was detected. The second set indicated a significant (p\u3c0.01) interaction effect between extract and microorganism. Although no significant differences in ZOI were observed for microorganisms exposed to DMSO, CPE and DEC; one particular microorganism VREF was found to be the most susceptible to DEE. In addition, findings of this study show the potential of Z. zanthoxyloides as a source of broad-spectrum antimicrobial compounds. © 2012 Academic Journals Inc