Sesquiterpenes from the Fruiting Bodies of Ramaria formosa and Their Human Neutrophil Elastase Inhibitory Activity

Two new sesquiterpene derivatives (1 and 2), ramarin A (1) and ramarin B (2), together with three known compounds (3–5) were isolated from the fruiting bodies of Ramaria formosa. The structures of the two sesquiterpenes were established by extensive spectroscopic studies and chemical evidence. The inhibitory activity of the isolated compounds (1–5) against human neutrophil elastase (HNE) was evaluated in vitro. All compounds tested inhibited HNE by 35–30% at the highest concentration used (100 µM), whereas the positive control, epigallocatechin gallate (EGCG), exhibited 60% inhibition at 100 µM.