Isoxazole Derivatives as Potential Pharmacophore for New Drug Development

Isoxazoles are five-membered aromatic heterocyclic compounds in which oxygen and nitrogen atoms are present at positions 1 and 2 of the ring system. Isoxazole derivatives play a vital role due to their diverse biological activities, such as antimicrobial, antifungal, anti-viral, anti-tubercular, anti-epileptic, anti-diabetic, anticancer, anthelmintic, antioxidant, antipsychotic, antimalarial, analgesic, anti-inflammatory, etc. Isoxazole scaffold is present in various drug molecules, such as leflunomide (antirheumatic), valdecoxib (non-steroidal anti-inflammatory drug), and zonisamide (anti-convulsant). Similarly, isoxazole derivatives such as isocarboxazid act as monoamine oxidase inhibitors. It is used to treat symptoms of depression that may include anxiety, panic, or phobias. Whereas the isoxazole derivatives, including sulfamethoxazole, sulfisoxazole, and oxacillin, are used clinically for the treatment of bacterial infections. Isoxazole pharmacophore is also present in β-lactamase resistant antibiotics such as cloxacillin, dicloxacillin, and flucloxacillin. Cycloserine is a naturally occurring antibiotic that possesses isoxazole moiety with anti-tubercular, activity. This study focuses on the therapeutic potentials of isoxazole derivatives in new drug development.