Anti‐Inflammatory Effect Fraction of <i>Bletilla striata</i> and Its Protective Effect on LPS‐Induced Acute Lung Injury
Chunchun Zhang, Dandan Ning, Jieli Pan, Cheng Chen, Chengxian Gao, Zhishan Ding, Fusheng Jiang, Meiya Li
Abstract
Bletilla striata is a well‐known traditional Chinese herb with anti‐inflammatory properties that is widely used in the treatment of lung conditions such as silicosis, tuberculosis, and pneumogastric hemorrhage. However, little information on the anti‐inflammatory ingredients and their activities is available. In this study, an effect fraction of Bletilla striata (EFBS) was enriched, and its anti‐inflammatory activities and underlying mechanisms were investigated. EFBS was enriched by polyamide column chromatography and characterized by HPLC; an LPS‐induced acute lung injury model was used to evaluate the anti‐inflammatory activities of EFBS. Meanwhile, the main anti‐inflammation‐contributing ingredients and possible molecular mechanism of anti‐inflammatory activity in EFBS were verified by component‐knockout method combined with LPS‐induced RAW264.7 cell model. The EFBS mainly consisted of coelonin (15.88%), batatasin III (32.49%), 3 ′ ‐ O ‐methylbatatasin III (6.96%), and 3‐hydroxy‐5‐methoxy bibenzyl (2.51%). Pretreatment with the EFBS (20 mg/kg and 60 mg/kg) for five days prior to the administration of LPS resulted in decreases in wet‐to‐dry lung weight ratio, neutrophil number, MPO activity, total protein concentration, NO level, and MDA level, as well as IL‐1 β , IL‐6, MCP‐1, and TNF‐ α concentrations in the bronchoalveolar lavage fluid. Western blot analysis demonstrated the increased expressions of iNOS, COX‐2, and NF‐ κ B p65 in the LPS treatment group, all of which were ameliorated by EFBS pretreatment. Histological examination confirmed the protective effect of the EFBS. Additionally, component‐knockout assay confirmed that these four quantitative components contributed significantly to the anti‐inflammatory effect of EFBS. Coelonin, batatasin III, 3 ′ ‐ O ‐methylbatatasin III and 3‐hydroxy‐5‐methoxy bibenzyl were the main anti‐inflammatory components of EFBS and could regulate the expression of downstream inflammatory cytokines by inhibiting p65 nuclear translocation. These findings uncover, in part, the molecular basis underlying the anti‐inflammatory activity of Bletilla striata .