Identification and characterization of a novel elastase inhibitor from Hirudinaria manillensis.

A large number of protease inhibitors have been found from leeches, which are essential in various physiological and biological processes. In the curret study, a novel elastase inhibitor was purified and characterized from the leech of Hirudinaria manillensis, which was named HMEI-A. Primary structure analysis showed that HMEI-A belonged to a new family of proteins. HMEI-A exerted inhibitory effects on elastase and showed potent abilities to inhibit elastase with an inhibition constant (Ki) of 1.69 × 10-8 mol·L-1. Further study showed that HMEI-A inhibited the formation of neutrophil extracellular trap (NET). These results suggested that HMEI-A from the leech of H. manillensis is a novel elastase inhibitor which can suppress NET formation. It may play a significant role in blood-sucking of leeches and is a potential candidate as an anti-inflammatory agent.

Seven new veratramine-type alkaloids with potent analgesic effect from Veratrum taliense.

ETHNOPHARMACOLOGICAL RELEVANCE: Veratrum taliense is traditionally used TCMs in Yunnan province of China for pain and inflammation. Previous research and clinical applications have shown that V. taliense had significant analgesic activity. Jevine-type alkaloids were shown to be one of the anti-inflammatory and analgesic agents from V. taliense. However, other types of compounds from V. taliense related to its traditional use remains unknown. AIM OF THE STUDY: To identify veratramine-type steroidal alkaloids with analgesic effects from the roots and rhizomes of V. taliense. MATERIALS AND METHODS: Compounds were isolated from the roots and rhizomes of V. taliense by chromatographic separation. Their structures were elucidated based on UV, IR, NMR and MS spectra data. Analgesic activity was assessed with acetic acid-induced writhing in mice model. RESULTS: Seven new veratramine-type alkaloids were isolated from the roots and rhizomes of V. taliense. They all exhibited significant analgesic activity, of which alkaloids 1 and 4 were more potent antalgic than the well-known analgesic drug, pethidine. CONCLUSIONS: The veratramine-type alkaloids from V. taliense may serve as new leads for the discovery of analgesic drugs.