Covid-19: Pathophysiology; Mechanism of Transmission and Possible Molecular Drug Target for Management.

Coronavirus disease 2019 (COVID-19) is caused by Severe Acute Respiratory Syndrome Coronaviruses 2 (SARS-CoV-2). At present, it is a potentially fatal disease and is of great global public health concern. The pathophysiological understanding of the mode of transmission of COVID-9 and the possible molecular targets are exploring successively to fight against this contagious disease. In this pandemic situation, a large number of countries have been forced to do social distancing and lockdown. The two main pathways of SARS-CoV-2 transmission include (1) droplet infection via the respiratory secretions or by close person to person contact, whereas (2) faecal to oral route transmission is also possible. Thus, the route of entry of SARS-CoV-2 is through the nasal and or oral cavity. Here, we briefly reviewed the current knowledge about COVID-19, considering the potential explanation of the mode of transmission and the different possible molecular drug targets. We highlighted potential approaches to address the antiviral therapy inhibiting the replication of SARS-CoV-2 in the host targeting (a.) RNA-dependent RNA polymerase (b.) serine protease and (c.) proteolytic activation pathways or the cell membrane receptor called the angiotensin- converting enzyme-2 (ACE2). The recently exercised immuno-enhancement therapy to fight against SARS-CoV-2 and treatment strategy using drug combination are also explored here in this review.

Effect of Aerva sanguinolenta (Lal bishalyakarani) plant extract on biofilm-induced human enamel demineralization: An in vitro study.

BACKGROUND: Controlling cariogenic biofilm formation by plant extracts could add to preventive strategies to dental caries. OBJECTIVE: To evaluate in vitro the role of Aerva Sanguinolenta ethanolic extract on biofilm-induced microbial human enamel demineralization. METHODOLOGY: The prepared enamel sections of study group (SG), positive control group (PCG), and negative control group (NCG) were immersed in 2 ml of 0.2% ethanolic extract of A. sanguinolenta, 0.12% chlorhexidine, and distilled water, respectively, for 2 min before subjecting to closed batch culture technique utilizing mono- or dual-species culture media of Streptococcus mutans and Lactobacillus acidophilus. Quantification of biofilm and demineralization of enamel was performed by crystal violet (CV) assay and scanning electron microscope (SEM) attached to energy-dispersive X-ray analysis, respectively. STATISTICAL ANALYSIS: Two-way ANOVA and Tukey's test were used for analysis. RESULTS: CV assay of biofilm recorded the highest and lowest optical absorbance value in NC3 (2.728660) and PC3 (0.364200), respectively. Thus, biofilm formation is highest in NCG and lowest among PCG. Surface roughness and porosity in enamel are greatest among NCG and lowest among SG as evident by SEM. Wt% of calcium (S3 47.7170) and phosphorus ion (S3 22.7330) was highest in SG, closely resembling that of B enamel (Ca = 41.9530, P = 19.6650). Wt% of oxygen is lowest in SG (S3 28.8920) and resembles baseline O2 (37.4950). Thus, the amount of biofilm formation is moderate and amount of demineralization of enamel is least among SGs. CONCLUSION: Enamel exposed to 2 ml of 0.2% solution of A. sanguinolenta for 2 min could fairly inhibit formation of biofilm and positively inhibit underlying demineralization in cariogenic environment.