Biological Applications of Isoniazid Derived Schiff Base Complexes: An Overview

Antibiotic resistance has been growing at an alarming rate and consequently the activity of antibiotics against Gram-negative and Gram-positive bacteria has dropped dramatically day by day. In this sense there is a strong need to synthesis new substances that not only have good field of activity, but having new appliances of action. Inorganic compounds particularly metal complexes have played a significant role in the development of new metal based drugs. Like few compounds, isonicotinic acid hydrazide (Isoniazid INH) is well known as first-line anti-tuberculosis (TB) drug to treat TB infection worldwide for more than 60 years. Unfortunately, people are only dependent on this drug and consequently, the rate of use of this drug has been increasing day by day. As the bacterial strains resistant to isoniazid are getting same for the long-term extensive use and even abuse so there is an urgent need to synthesis new drugs not only for anti-tuberculosis properties but also for having significant activity in various biological areas with mechanisms of action. Isoniazid derivatives and their metal complexes, particularly medicinal inorganic metal complexes have been considered as new drugs for their antimicrobial activities like anti-bacterial, anti-fungal, anti-tuberculosis, DNA binding, antioxidant, cytotoxic, scavenging and antiviral activities. In this review, we have focused on the various synthesized metal complexes of isoniazid and its hydrazones and have compared their biological activities which are more or less strong against microorganisms. It is found that INH has moderate to strong antimicrobial activity.