Molecules, Vol. 19, Pages 13473-13485: Hypotensive Effects and Angiotensin-Converting Enzyme Inhibitory Peptides of Reishi (Ganoderma lingzhi) Auto-Digested Extract (Molecules)

Reishi (Ganoderma lingzhi) has been used as a traditional medicine for millennia. However, relatively little is known about this mushroom`s proteins and their bioactivities. In this study, we used reishi`s own proteases to hydrolyze its protein and obtained auto-digested reishi (ADR) extract. The extract was subjected to in vitro assays and administered to spontaneous hypertensive rats (SHRs) to determine its potential for use as a hypotensive medication. Bioassay-guided fractionation and de novo sequencing were used for identifying the active compounds. After 4 h administration of ADR, the systolic pressure of SHRs significantly decreased to 34.3 mmHg (19.5% change) and the effect was maintained up to 8 h of administration, with the decrease reaching as low as 26.8 mmHg (15% reduction-compare to base line a decrease of 26.8 mmHg is less than a decrease of 34.3 mmHg so it should give a smaller % reduction). Eleven peptides were identified and four of them showed potent inhibition against ACE with IC50 values ranging from 73.1 ?M to 162.7 ?M. The results showed that ADR could be a good source of hypotensive peptides that could be used for antihypertensive medication or incorporation into functional foods.