COVID-19 Challenge: A Quest for Effective Vaccine Strategies Against Circulating and Emerging SARS-CoV-2 Variants

INTRODUCTION

SARS-CoV-2 belongs to the coronavirus family, a large family of viruses infecting avian and mammalian hosts. Accumulated mutations over time in the genome of SARS-CoV-2 have given rise to different variants differing in type and sequence. Variants that did not affect transmissibility, infectivity, and severity have gone unnoticed, and mutations that made the virus unfit for survival were deleted eventually from the gene pool. An emerging variant in the host population needs to be monitored closely for its infection consequences. In addition, the variants of concern (VOC) need to be focused on developing effective disease-fighting regimes. As viral epidemics are better fought using effective vaccines, several vaccines have been developed and used since December 2020. The central point of the present study is the continuous variation in the genome of SARS-CoV-2, instigating the researchers to refine their modus operandi to fight against COVID-19.

METHODS

Prominent medical and literature databases were searched using relevant keywords to gather study results, reports, and other data helpful in writing this traditional, narrative review.

RESULTS

This article successfully collates information about the structure and life cycle of SARS-CoV-2, followed by types and nomenclature of mutations in SARS-CoV-2. Variants B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma), B.1.617.2 (Delta), and B.1.1.529 (Omicron) are current VOCs due to their widespread transmission capability and probable immune evasion. Furthermore, this review article presents information about the major vaccines available and those under development. Based on the original and new strains of SARS-CoV-2, 19 vaccines have been granted emergency use or conditional marketing approvals, 141 are under clinical development, and 194 in preclinical development stages worldwide.

CONCLUSION

Continuous variation in the genome of SARS-CoV-2, presenting new VOCs frequently, has posed a compelling need to amend and evolve current and future vaccine development strategies to overpower the ever-evolving virus.

An Overview of Tetramethylpyrazine (Ligustrazine) and its Derivatives as Potent Anti-Alzheimer’s Disease Agents

Abstract:

Tetramethylpyrazine (TMP), or ligustrazine, is an alkaloid isolated from the Chinese herb Ligusticum wallichii. It is known for its broad-spectrum medicinal properties against several diseases, and various studies have shown that it can modulate diverse biological targets and signaling pathways to produce neuroprotective effects, especially against Alzheimer’s disease (AD). This has attracted significant research attention evaluating TMP as a potent multitarget anti-AD agent. This review compiles the results of studies assessing the neuroprotective mechanisms exerted by TMP as well as its derivatives prepared using a multi-target-directed ligand strategy to explore its multitarget modulating properties. The present review also highlights the work done on the design, synthesis, structure-activity relationships, and mechanisms of some potent TMP derivatives that have shown promising anti-AD activities. These derivatives were designed, synthesized, and evaluated to develop anti-AD molecules with enhanced biological and pharmacokinetic activities compared to TMP. This review article paves the way for the exploration and development of TMP and TMP derivatives as an effective treatment for AD.