Blackberry phenolic and volatile extracts inhibit cytokine secretion in LPS-inflamed RAW264.7 cells

Abstract

The anti-inflammatory activity of blackberries has been attributed to phenolic compounds, especially anthocyanins. The present study hypothesized that volatiles could contribute to anti-inflammatory activity as well. The anti-inflammatory properties of three blackberry genotypes varying in total volatile and phenolic contents were assessed by measuring concentrations of nitric oxide (NO), interleukin-6 (IL-6) and tumor necrosis factor -α  (TNF-α) within LPS-inflamed RAW264.7 murine macrophage cells after a preventive treatment of either a phenolic or a volatile extract. Extracts from blackberry genotypes A2528T, A2587T and Natchez had total phenolic contents of 4315, 3369 and 3680 µg/mL, respectively, and total volatile contents of 283, 852 and 444 ng/mL, respectively. Phenolic and volatile extracts of all genotypes significantly lowered the secretion of NO, IL-6 and TNF-α in ranges varying between 20-42%, 34-60% and 28-73% inhibition, respectively. Volatile extracts exhibited greater anti-inflammatory properties than phenolic extracts, despite being present at much lower concentrations in the berries. Further research is needed to assess bioavailability and anti-inflammatory effect of blackberry volatiles in vivo.