Zhang J, Xu HY, Wu YJ, Zhang X, Zhang LQ, Li YM. Neutrophil elastase inhibitory effects of pentacyclic triterpenoids from Eriobotrya japonica (
loquat leaves).
J Ethnopharmacol 2019;
242:111713. [PMID:
30703491 PMCID:
PMC7127461 DOI:
10.1016/j.jep.2019.01.037]
[Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/07/2019] [Accepted: 01/27/2019] [Indexed: 05/02/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE
Eriobotrya japonica, a traditional herbal medicine in China and Japan, has long been used to treat chronic bronchitis and coughs.
AIM OF THE STUDY
Pentacyclic triterpenoids (PTs), especially ursolic acid (UA), have been found as reversibly and competitively human neutrophil elastase (HNE) inhibitors. However, the limited solubility and poor bioavailability of PTs hinder their clinical use. Crude plant extracts may have a greater activity than isolated constituents of the equivalent dosage. In this study, an Eriobotrya japonica (loquat leaves) extract (triterpenoid composition of loquat leaves, TCLL) with enriched PTs such as UA was prepared. The study aims to compare the HNE inhibitory (HNEI) effect in vitro and the therapeutic effect on acute lung injury (ALI) in vivo between TCLL and UA.
MATERIALS AND METHODS
An HNEI activity bioassay was performed with Sivelestat sodium hydrate as a positive control. A lipopolysaccharide (LPS)-induced lung inflammatory model was established to evaluate TCLL's therapeutic effect on ALI in vivo. The absorption of UA in TCLL and in UA alone was determined using a Caco-2 cell uptake model and LC-MS.
RESULTS
The IC50 values of TCLL and UA for the HNEI effect were 3.26 ± 0.56 μg/mL and 8.49 ± 0.42 μg/mL (P < 0.01), respectively. TCLL significantly improved the inflammatory cells and inflammatory cytokine production in mice compared with the LPS group (P < 0.05). Additionally, it performed better than the UA alone group (P < 0.05). Moreover, the uptake by Caco-2 cells of UA in TCLL was higher than that in UA alone (P < 0.05).
CONCLUSION
TCLL has a significant HNEI effect in vitro and a therapeutic effect on LPS-induced inflammation in a mouse model. Both the effects are more efficient than UA. Improved absorption of PTs in TCLL may be one explanation for these results.
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