Mercaptonicotinic acid compound and preparation method and use thereof

The present invention discloses a mercaptonicotinic acid compound and preparation method and use thereof; the structural formula of the compound is as shown in Formula I. Experimentation demonstrates that the mercaptonicotinic acid compound inhibits in vitro botulinum toxin endopeptidase activity and Clostridium tetanus toxin endopeptidase activity, has a significant protective effect on botulinum toxin poisoning of mice, and can be used for the prevention and/or treatment of botulism and prevention of botulinum toxin-exposed drugs and tetanus drugs.