Phenolic profiles in the peels of three wampee (Clausena lansium (Lour.) Skeels) fruit cultivars and immune-modulatory activity through the cluster of differentiation 14-mitogen activated protein kinase/nuclear factor kappa B pathways.

ETHNOPHARMACOLOGICAL RELEVANCE: The peels of wampee (Clausena lansium (Lour.) Skeels) fruits have been ethnomedicinally used to cure malarial fever, coughs, bronchitis, viral hepatitis, and gastrointestinal disorders, suggesting potential immunoprotective and anti-inflammatory properties.

AIM OF THE STUDY: This study aimed to compare the phenolic profiles in the peels of three wampee fruit cultivars and initially reveal the comprehensive immune-modulatory mechanisms of the phenolic fraction.

MATERIALS AND

METHODS

The fruits of Golden wampee (GLW), Jixin wampee (JXW) and Guifei wampee (GFW) were collected. Their peels (GLP, JXP, GFP) were used to extract crude phenols (GLPE, JXPE, GFPE). JXPF was a phenolic fraction purified from JXPE using preparative high-performance liquid chromatography, which contained the mixture of various phenolic compounds in JXP. Phenolic contents were quantified using HPLC. The binding receptors and immune-modulatory pathways were investigated in LPS-induced RAW 264.7 cells.

RESULTS

JXP exhibited higher proportions of phenolic compounds, including myricetin-3-O-galactoside, nicotiflorin, rutin, isorhamnetin-3-O-neohesperidoside, isoquercitrin, quercitrin, and 8-hydroxypsoralen. GLPE, JXPE and GFPE reduced LPS-induced overexpression of NO, IL-6 and TNF-α, maintaining these mediators at moderate levels, which indicated immune-modulatory activity. The phenolic compounds in JXPF could occupy the CD14 receptor on macrophage surfaces and finally suppress the phosphorylation of ERK 1/2, p38, JNK, IκBα, and p65 in the MAPK and NF-κB signaling pathways.

CONCLUSIONS

JXW was identified as a superior cultivar with a higher abundance of phenolic compounds in its peels. The phenols derived from wampee peels demonstrated potential as immune-modulatory agents.