Metformin as a protective agent against natural or chemical toxicities: a comprehensive review on drug repositioning

Background Metformin is the first prescribed drug for hyperglycemia in type 2 diabetes mellitus. Mainly by activating AMPK pathway, this drug exerts various functions that among them protective effects are of the interest. Purpose Herein, we aimed to gather data about the protective impacts of metformin against various natural or chemical toxicities. Results An extensive search among PubMed, Scopus, and Google Scholar was conducted by keywords related to protection, toxicity, natural and chemical toxins and, metformin. Our literature review showed metformin alongside its anti-hyperglycemic effect has a wide range of anti-toxic effects against anti-tumour and routine drugs, natural and chemical toxins, herbicides and, heavy metals. Conclusion It is evident that metformin is a potent drug against the toxicity of a broad spectrum of natural, chemical toxic agents which is proved by a vast number of studies. Metformin mainly through AMPK axis can protect different organs against toxicities. Moreover, metformin preserves DNA integrity and can be an option for adjuvant therapy to ameliorate side effect of other therapeutics.