Anti-oxidative fraction of lycorma delicatula alleviates inflammatory indicators

Abstract

Lycorma delicatula is a reluctant pest capable of living in the stems of several tree species. The population has recently expanded in Korea due to several environmental factors including climate change. However, the precise reasons for this rapid and drastic increase in population size remain unknown. In order to examine the potential utility of this surplus biomass of Lycorma delicatula, we prepared an aqueous fraction from a dried imago, and tested its various anti-inflammatory activities and effects on cytokine levels in lipopolysaccharide (LPS)-activated RAW264.7 cells. The aqueous extract of Lycorma delicatula showed potent inhibitory activity on nitric oxide production, by more than 60%, at a concentration of 300 g/mL. We also evaluated interleukin (IL)-13 level using enzyme-linked immunosorbent assays (ELISAs). The anti-oxidative fraction of Lycorma delicatula inhibited LPS-induced IL-13 production in a dose-dependent manner, and T-bet promoter activity of cells treated with 300 g/mL of Lycorma delicatula extract was also dramatically inhibited to 62% of that of LPS-treated cells. Furthermore, we compared matrix metalloproteinase-7 (MMP-7), -9, -14 and -17 expressions using reverse transcription-polymerase chain reaction (RT-PCR), which showed a drastic decrease in RNA levels in cells treated with the anti-oxidative fraction. Together, the present results suggest that the aqueous fraction of Lycorma delicatula has potential to ameliorate inflammatory characteristics during an inflammation event, supporting the idea that the fraction may be applied as a biomaterial to prevent inflammatory damage in skin tissues.