American Society of Hirudotherapy

Old and new natural products as the source of modern antithrombotic drugs

Research article published in Planta medica (1991)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Research reportDrug DevelopmentBeretz A et al. · Planta medica, 1991

Abstract

Natural compounds have been the first historical source of antithrombotic compounds (heparin, vitamin K antagonists, streptokinase, urokinase); molecules extracted from plants or animals still provide some of the most original and promising approaches for the discovery of new drugs in this class. In this review, we will briefly describe three examples of current research trends that could lead to the development of new antithrombotic drugs of natural origin. Flavonoids have been shown to be inhibitors of cyclic nucleotide phosphodiesterase; this enzymatic activity is one of the main mechanisms of inhibition of aggregation of blood platelets by flavonoids. Some of these compounds could represent templates for the development of new inhibitors of platelet activation. Garlic ( ALLIUM SATIVUM) has been shown to inhibit platelet aggregation IN VIVO and IN VITRO; a number of active principles has now been identified and their mechanisms of action are currently being explored. An ancient remedy, the medicinal leech ( HIRUDO MEDICINALIS), has been found to contain several potent anticoagulant proteins. Among them, hirudin, a polypeptide of 65 amino acids, has been identified as one of the most potent inhibitors of thrombin. The production of sufficient amounts of hirudin through molecular biology techniques has now allowed the performance of clinical trials. These three examples show that careful consideration of biochemical, ethnopharmacological, or toxicological properties of natural products can still constitute a valuable basis for the development of new drugs.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Publication typeJournal Article

Summary

Peer-reviewed research on therapeutic compound development relevant to leech-derived anticoagulants and antithrombotic agents. Indexed in PubMed and verified against the NCBI record.

Why This Matters for Hirudotherapy

This review surveys natural products as sources of antithrombotic drugs, covering platelet-inhibiting flavonoids, garlic (Allium sativum), and the medicinal leech (Hirudo medicinalis), and highlights hirudin, a 65-amino-acid leech polypeptide identified as one of the most potent thrombin inhibitors known, noting that recombinant production had by then enabled clinical trials. It sits at the center of the ASH secretome drug-discovery narrative, documenting how a classical leech anticoagulant moved from ancient remedy to a defined molecule and a template for modern thrombin-directed therapeutics. Caveat: this is a narrative review from 1991 that summarizes the state of research at that time rather than reporting new trial outcomes, so it is best cited for historical and mechanistic framing of hirudin's drug-discovery significance, not as current clinical evidence.

Citation

Old and new natural products as the source of modern antithrombotic drugs.

Beretz A et al. · Planta medica, 1991

Added to ASH library: May 28, 2026 · Site last updated: June 18, 2026

This website provides educational information and does not constitute medical advice, diagnosis, or treatment recommendations. Medicinal leech therapy carries clinically meaningful risks and should be performed only by qualified clinicians under institutionally approved protocols. FDA 510(k) clearance for medicinal leeches is limited to specific indications; investigational and off-label discussions are labeled accordingly. For patient-specific guidance, consult a qualified healthcare provider.