Graphical abstract Most of the currently marketed drugs consist of heterocyclic scaffolds containing nitrogen and or oxygen as heteroatoms in their structures. Several research groups have synthesized diversely substituted 1,2,4-oxadiazoles as anti-infective agents having anti-bacterial, anti-viral, anti-leishmanial, etc. activities. For the first time, the present review article will provide the coverage of synthetic account of 1,2,4-oxadiazoles as anti-infective agents along with their potential for SAR, activity potential, promising target for mode of action. The efforts have been made to provide the chemical intuitions to the reader to design new chemical entity with potential of anti-infective activity. This review will mark the impact as the valuable, comprehensive and pioneered work along with the library of synthetic strategies for the organic and medicinal chemists for further refinement of 1,2,4-oxadiazole as anti-infective agents.

Type-2 diabetes mellitus (T2DM) is a chronic immuno-inflammatory and metabolic disease characterized by hyperglycemia and insulin resistance with corresponding hyperinsulinemia. On the other hand, Alzheimer’s disease (AD) is a neurodegenerative disease involving cognitive impairment, neuronal dysfunction, and memory loss. Several recently published literatures suggest a causal relationship between T2DM and AD. In this review, we have discussed several potential mechanisms underlying diabetes-induced cognitive impairment which include, abnormal insulin signaling, amyloid-β accumulation, oxidative stress, immuno-inflammation, mitochondrial dysfunction, advanced glycation end products, acetylcholinesterase and butyrylcholinesterase, advanced lipid peroxidation products, and apolipoprotein E. All these interconnected mechanisms may act either individually or synergistically which eventually leads to neurodegeneration and AD.

Malaria has been a major parasitic disease in tropical and subtropical regions and is estimated to kill between one and two million people (mainly children) every year. Novel anti-malarial agents are urgently needed to combat the malarial parasites enduring resistance to the current medications, leading to increased morbidity and mortality. The heterocycles, holding a prominent position in chemistry and found in both natural and synthetic sources, have shown several biological activities including anti-malarial activity. Towards this goal, several research groups have reported the design and development of novel and potential anti-malarial agents like artemisinin, benzimidazole, benzothiazole, chalcone, cyclopeptide, fosmidomycin, furan, indole oxadiazole, 2-oxindoles, peroxides, pyrazole, pyrazolines, pyridines, pyrimidine, pyrrolidine, quinazoline, quinazolinone, quinolone, quinoline, thiazole, triazole and other scaffolds acting against newly emerging anti-malarial targets. The present work reports the complete quinquennial coverage of anti-malarial agents reported during 2016-2020 with a view of providing the merits and demerits of reported anti-malarial scaffolds, structure-activity relationship, along with their in vitro/ in vivo/ in silico profiles to the medicinal chemists working in the field of design and discovery of novel anti-malarial agents.