Phytochemical Constituents of Citrus hystrix DC. Leaves Attenuate Inflammation via NF-?B Signaling and NLRP3 Inflammasome Activity in Macrophages.

ABSTRACT: Citrus hystrix DC. (CH) is found in many countries in Southeast Asia. This plant has been reported for anti-microbial, anti-cancer and anti-inflammatory bioactivities. However, the anti-inflammatory and anti-inflammasome properties of the leaves remain poorly understood. This study aimed to investigate the effect of CH leaves on NLRP3 and NF-?B signaling pathways. CH leaves were sequentially extracted using hexane, ethyl acetate and 95% ethanol to give three crude extracts. An active compound, lupeol was fractionated from the ethanolic extract using chromatographic techniques, and its structure was identified and confirmed by spectroscopic methods. Anti-inflammatory activities were observed on both lipopolysaccharide-stimulated and NLRP3 adenosine triphosphate-induced macrophages. The release of pro-inflammatory cytokines (IL-1?, IL-6 and TNF-?) was analyzed by Enzyme-Linked Immunosorbent Assay (ELISA). Real-time qRT-polymerase chain reaction (PCR) was used to measure inflammatory-associated gene expression. NF-?B protein expressions were investigated using the immunoblotting technique. The active fraction of ethanolic CH leaves and lupeol significantly reduced the release of pro-inflammatory cytokines and suppressed the expression of both inflammasome genes and NF-?B proteins. The ethanolic extract of CH leaves and lupeol showed potent anti-inflammatory activities by targeting NF-?B and NLRP3 signaling pathways.

SUBMITTER: Buakaew W 

PROVIDER: S-EPMC7829879 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature