The Potential of Systems Biology to Discover Antibacterial Mechanisms of Plant Phenolics

Drug resistance of bacterial pathogens is a growing problem that can be addressed through the discovery of compounds with novel mechanisms of antibacterial activity. Natural products, including plant phenolic compounds, are one source of diverse chemical structures that could inhibit bacteria through novel mechanisms. However, evaluating novel antibacterial mechanisms of action can be difficult and is uncommon in assessments of plant phenolic compounds. With systems biology approaches, though, antibacterial mechanisms can be assessed without the bias of target-directed bioassays to enable the discovery of novel mechanism(s) of action against drug resistant microorganisms. This review article summarizes the current knowledge of antibacterial mechanisms of action of plant phenolic compounds and discusses relevant methodology

Computational Ranking of Yerba Mate Small Molecules Based on Their Predicted Contribution to Antibacterial Activity against Methicillin-Resistant Staphylococcus aureus

The aqueous extract of yerba mate, a South American tea beverage made from Ilex paraguariensis leaves, has demonstrated bactericidal and inhibitory activity against bacterial pathogens, including methicillin-resistant Staphylococcus aureus (MRSA). The gas chromatography-mass spectrometry (GC-MS) analysis of two unique fractions of yerba mate aqueous extract revealed 8 identifiable small molecules in those fractions with antimicrobial activity. For a more comprehensive analysis, a data analysis pipeline was assembled to prioritize compounds for antimicrobial testing against both MRSA and methicillin-sensitive S.aureus using forty-two unique fractions of the tea extract that were generated in duplicate, assayed for activity, and analyzed with GC-MS. As validation of our automated analysis, we checked our predicted active compounds for activity in literature references and used authentic standards to test for antimicrobial activity. 3,4-dihydroxybenzaldehyde showed the most antibacterial activity against MRSA at low concentrations in our bioassays. In addition, quinic acid and quercetin were identified using random forests analysis and 5-hydroxy pipecolic acid was identified using linear discriminant analysis. We also generated a ranked list of unidentified compounds that may contribute to the antimicrobial activity of yerba mate against MRSA. Here we utilized GC-MS data to implement an automated analysis that resulted in a ranked list of compounds that likely contribute to the antimicrobial activity of aqueous yerba mate extract against MRSA

COMPOSITION AND BIOACTIVE PROPERTIES OF YERBA MATE ( Ilex paraguariensis A. St.-Hil.): A REVIEW

Yerba Mate is a popular tea beverage produced and consumed in the South American countries of Argentina, Brazil, Chile, Paraguay, and Uruguay, and is processed from the leaves and stems of Ilex paraguariensis A. St.-Hil., a perennial shrub from the Aquifoliaceae family. Production occurs in six stages: harvesting older leaves and small stems, roasting by direct fire, drying under hot air, milling to specified size, aging to acquire optimal sensory attributes, and final packaging. While grown and consumed for centuries in South America, its popularity is increasing in the United States because of demand by consumers for healthier, more natural foods, its filling a niche for a different type of tea beverage, and for Yerba Mate's potential health benefits—antimicrobial, antioxidant, antiobesity, anti-diabetic, digestive improvement, stimulant, and cardiovascular properties. Cultivation, production and processing may cause a variation in bioactive compounds biosynthesis and degradation. Recent research has been expanded to its potential use as an antimicrobial, protecting crops and foods against foodborne, human and plant pathogens. Promising results for the use of this botanical in human and animal health has prompted this review. This review focuses on the known chemical composition of Yerba Mate, the effect of cultivation, production and processing may have on composition, along with a specific discussion of those compounds found in Yerba Mate that have antimicrobial properties

Overlay of initial yerba mate extract fraction chromatograms.

<p>A) The black chromatogram corresponds to a yerba mate extract fraction that demonstrated antibacterial activity against methicillin-resistant <i>Staphylococcus aureus</i> (MRSA); the red chromatogram corresponds to a yerba mate fraction that had no antibacterial activity against MRSA. B) Retention times of identified compounds and quantification in sorbitol equivalents were reported.</p

Classification accuracy of a single major mz peak for each of the 3 identified compounds of interest.

<p>Classification accuracy of a single major mz peak for each of the 3 identified compounds of interest.</p

Rank biased overlap comparison of lists.

<p>Rank biased overlap comparison of lists.</p

Top ten results for each attribute ranking method.

<p>Top ten results for each attribute ranking method.</p

Growth of methicillin-sensitive (SA) and methicillin-resistant <i>Staphylococcus aureus</i> MRSA) in the presence of pure compounds.

<p>At concentrations of 10 μg/ml (chemical_1), 20 μg/ml (chemical_2) and 100 μg/ml (chemical_3), growth with compounds was compared to the positive growth control (no chemical added) to determine inhibitory activity. Statistically significant differences greater (*) or less (**) than control are marked by asterisks. Growth of A. SA 113, B. SA 27708, C. MRSA 35591, and D. MRSA 35593 are reported at 48 h. SA113 had a significant block by treatment interaction, so no conclusions can be drawn from it.</p

Predicted Functional Groups from Golm.

<p>Predicted Functional Groups from Golm.</p

Top 20 unique retention times ranked by antimicrobial significance against MRSA using random forests.

<p>Top 20 unique retention times ranked by antimicrobial significance against MRSA using random forests.</p