Peeling Away Problems
The Antioxidating, Antimicrobial, and Antimutagenic Effects of Tree Bark
|Results||Conclusions||Sources of Error||Applications||Acknowledgements||Bibliography||Glossary|
Results for the Folin-Ciocalteau Assay.
Results for the FRAP Assay.
Results for the Bacterial Susceptibility Tests.
Results for the Ames Test.
In both the Folin-Ciocalteau Method and the FRAP Assay, the same patterns were shown (Fig.1 and Fig.2). The white spruce bark extract always had the greatest amounts of polyphenols and antioxidating activity by a large margin and the jack pine bark extract the least. The extracts made at 100ºC had more polyphenols and a greater antioxidating power than the extracts made at 50ºC.
In the bacterial susceptibility tests, all the extracts except for jack pine showed signs of strong inhibition (Table 1 and Fig. 3). For the E.coli strain, there was not much inhibition overall. However, for the other 3 strains (which are also considered ‘clinically important bacteria’): White spruce, paper birch, and trembling aspen extracts all showed strong inhibition.
These results are quite interesting since Paper Birch and Trembling Aspen both had lower levels of total polyphenol amounts and antioxidating activity compared to White Spruce (Fig. 1 and Fig.2), but had similar sized inhibition zones for the bacterial strains tested. This could be because some of the bacterial strains could be more affected by certain types of polyphenols or that the amount of antioxidating power has not a lot to do with antimicrobial ability. Finally, the extracts made at 100ºC had a slightly more inhibition on average compared to the extracts made at 50ºC.
In the Ames Test, Sodium Azide (NaN3) was used as a positive control. All four of the extracts, at a 1:60 dilution (1.6%), reversed the sodium azide-induced bacterial mutation by approximately 30% (Fig. 4). In a separate experiment, the white spruce extract also showed antimutagenic effects from the 1:100 diluted extract (1%) to the 1:1 diluted extract (100%). The 1%, 3%, 10%, and 33% extracts showed antimutagenic effects by decreasing colony numbers by ~25% and the 100% extract decreased the colony numbers by ~40% (Fig. 5).
I hypothesized that the tree bark from conifers will have the greatest antioxidating and antimicrobial effects and I hypothesized that the experiment which heats the water to 100ºC will extract greater amounts of polyphenol, thus the extracts have more antioxidating activity, and a greater antimicrobial and antimutagenic effect. My hypothesis was somewhat correct since White Spruce (a conifer) extract had the highest amount of total polyphenols and antioxidating activity. However, Jack Pine (the other conifer) extract had the lowest amounts of polyphenols and antioxidating activity. Also, in the bacterial inhibition tests and the Ames Test, the type of tree did not seem to matter. My other hypothesis about the two experiments was correct though, since the experiment that heated the water to 100ºC did extract greater amounts of polyphenols, and the 100ºC extracts had more antioxidating activity, and overall had a greater antimicrobial effect.