Distribution profiles of phenolic compounds in a cultivar of wampee (Clausena lansium (Lour.) Skeels) fruits and in vitro anti-inflammatory activity

The fruits of wampee (Clausena lansium (Lour.) Skeels), which contain significant amounts of phenolics, are frequently applied as traditional medications to prevent or relieve inflammatory symptoms. Green honey wampee (GHW) is a local cultivar specially cultivated in Lianjiang City, Guangdong Province.This study aimed to investigate phenolic distribution profiles in the peels, seeds and pulp of GHW as well as elucidate the underlying molecular mechanisms of the effective compounds for anti-inflammatory activity.Phenolic compounds in the extract were identified through UPLC-MS/MS and their ability to alleviate inflammation was assessed using RAW 264.7 macrophages exposed to lipopolysaccharide.Among the three parts of GHW fruits, the total phenolic contents followed a descending order of peels > pulp > seeds. Additionally, eighty-six phenols were tentatively determined from the three parts, of which flavonoids accounted for the highest proportion. Furthermore, the phenolic extract of peels, seeds and pulp exhibited potential anti-inflammatory activity through the suppression effect on different pro-inflammatory mediators (NO, IL-6 and TNF-α). Among the three principal phenolic compounds (rutin, quercitrin, isorhamnetin-3-O-neohesperidoside) detected in GHW fruits, quercitrin was proved to be a more important anti-inflammatory compound inhibiting the iNOS and TNF-α mRNA expressions through the suppression effect on the phosphorylation of IκBα and ERK, belonging to the NF-κB and MAPK signaling pathway respectively.Not only wampee pulp but also its by-products like peels and seeds are able to be comprehensively utilized as immunomodulatory supplements for daily diets due to their rich phenolic contents.