Globally, Alzheimer’s disease (AD) is one of the most prevalent age-related neurodegenerative disorders associated with cognitive decline and memory deficits due to beta-amyloid deposition (Aβ) and tau protein hyperphosphorylation. To date, approximately 47 million people worldwide have AD. This figure will rise to an estimated 75.6 million by 2030 and 135.5 million by 2050. According to the literature, the efficacy of conventional medications for AD is statistically substantial, but clinical relevance is restricted to disease slowing rather than reversal. Withaferin A (WA) is a steroidal lactone glycowithanolides, a secondary metabolite with comprehensive biological effects. Biosynthetically, it is derived from Withania somnifera (Ashwagandha) and Acnistus breviflorus (Gallinero) through the mevalonate and non-mevalonate pathways. Mounting evidence shows that WA possesses inhibitory activities against developing a pathological marker of Alzheimer’s diseases. Several cellular and animal models’ particulates to AD have been conducted to assess the underlying protective effect of WA. In AD, the neuroprotective potential of WA is mediated by reduction of beta-amyloid plaque aggregation, tau protein accumulation, regulation of heat shock proteins, and inhibition of oxidative and inflammatory constituents. Despite the various preclinical studies on WA’s therapeutic potentiality, less is known regarding its definite efficacy in humans for AD. Accordingly, the present study focuses on the biosynthesis of WA, the epidemiology and pathophysiology of AD, and finally the therapeutic potential of WA for the treatment and prevention of AD, highlighting the research and augmentation of new therapeutic approaches. Further clinical trials are necessary for evaluating the safety profile and confirming WA’s neuroprotective potency against AD.

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Background COVID-19 has mutation capability, and there are no specific drug therapies that are available to fight or inhibit the proteins of this virus. The present study aims to investigate the binding affinity of the bioactive and synthetic compounds with the main protease (Mpro) enzymes and angiotensin-converting enzyme 2 (ACE 2) by computational approach. PASS prediction, pharmacokinetics, and toxicological properties prediction studies were performed through the Google PASS prediction and Swiss ADME/T website. Besides, molecular docking studies were accomplished by BIOVIA Discovery Studio 2020, UCSF Chimera, and PyRx autodock vina. Results The docking scores were inferred and the selected compounds showed results varying from −3.2 to −9.8 (kcal/mol). Theaflavin scored the highest docking score to the 5REB, 6VW1, and 1R42 enzymes and showed the binding affinity as −6.3 kcal/mol, −9.8 kcal/mol, and −8.6 kcal/mol, respectively. Again, kaempferol showed the best binding affinity to the 7BQY (−7.1 kcal/mol) and 6Y2FB (−6.6 kcal/mol) enzymes. All the chemical constituents showed better probability in action in pass prediction analysis. Besides, no ligands (except theaflavin) have any conflict with Lipinski’s rules of five, which authorized the drug probability of these ligands. Conclusion Therefore, the selected compounds could be considered a potential herbal treatment source against SARS-CoV-2.