Date of Graduation

12-2020

Document Type

Thesis

Degree Name

Master of Science in Food Science (MS)

Degree Level

Graduate

Department

Food Science

Advisor/Mentor

Howard, Luke R.

Committee Member

Lee, Sun-Ok

Second Committee Member

Tipton, John R.

Keywords

berry; IL-6; inflammation; LPS; nitric oxide; TNF-a

Abstract

Berries are known for many health benefits including anti-inflammatory properties that lower risks of chronic diseases. These properties have been linked to high concentrations of phenolic compounds, especially anthocyanins. However, the present study hypothesized that volatiles could contribute to the berries’ bioactive properties. Thus, the objectives of this research are to profile the phenolic and volatile composition of 16 blackberry genotypes harvested at the Fruit Research Center of the University of Arkansas and to evaluate the antiinflammatory capacities of three selected genotypes on inflamed cells. Phenolic and volatile profiles were evaluated using chromatographic techniques. The three genotypes A2528T, A2587T and Natchez were selected based on their low (2419 ppb), medium (3882 ppb) and high (5574 ppb) concentration in total volatiles, respectively. The anti-inflammatory properties were assessed in vitro on LPS-inflamed RAW264.7 macrophage murine cells after a preventive treatment of either a 10-, 20- or 40-fold diluted phenolic extract, or a 2-, 4- or 8-fold diluted volatile extract. A2528T, A2587T and Natchez genotypes had total phenolic contents of 4,807, 4,115, 4,435 μg Gallic Acid Equivalent (GAE)/g, respectively and total volatile contents of 2,418, 5,574 and 3,882 ng/g, respectively. Phenolic extracts of A2528T, A2587T and Natchez diluted 10-fold inhibited nitric oxide (NO) production by 42%, 24% and 20% on average, respectively, while volatile extracts of the same genotypes diluted 2-fold inhibited NO production by 23%, 32% and 22% on average, respectively. The volatile extracts of all three genotypes (A2528T, A2587T and Natchez) at the 2-fold dilution inhibited interleukin-6 (IL-6) production by 40%, 58% and 45% on average, respectively. Within both the IL-6 and Tumor Necrosis Factor alpha (TNF-a) assays, there was a visual clue of an anti inflammatory effect of blackberry extracts, but the small sample size with a wide variability did not allow the statistical model to detect a strong significant difference between the extracts and the positive control.

Volatile compounds along with phenolics contributed to the berries’ anti-inflammatory effect. More data needs to be collected within the IL-6 and TNF-a tests to conclude a significant anti-inflammatory effect of blackberry phenolics and volatiles. Additional research is also needed to identify classes of volatiles responsible for anti-inflammatory activity, to determine potential synergistic effects between phenolic and volatile fractions, and to replicate the present finding on other cell lines.

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