Selenium as a chemoprotective anti-cancer agent: Reality or wishful thinking?

β-Sitosterol (beta-sitosterol) is a natural phytosterol of steroidal nature and similar to cholesterol. This review is devoted to claims of β-sitosterol effects on various types of cancer. Studies of its fate in the organism significantly improved with the development of modern instrumental analytical methods as they made it possible for scientist to identify β-sitosterol and other phytosterols in the presence of cholesterol to investigate qualitative and quantitative parameters of different systems: cells, tissues, animal and human organisms. Investigations of biological activities of β-sitosterol showed the anticarcinogenic and anticancer effects on cellular level. However, in vivo investigations did not lead to introduction of β-sitosterol among anticancer drugs. At this moment, benefits of β-sitosterol are widely accepted but more specific studies are necessary for clarification of β-sitosterol activities that would be of benefit to some cancer patients, especially suffering from breast and colon cancer.

At the beginning of 2020, the world was swept with a wave of a new coronavirus disease, named COVID-19 by the World Health Organization (WHO 2). The causative agent of this infection is the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The data available on one of the promising therapeutic agents—nucleotide analog remdesivir (Gilead Sciences number GS-5734)—were evaluated. These data were concerned with remdesivir activation from the prodrug to the active molecule—triphosphate containing 1′-cyano group and modified nucleobase. This triphosphate competes with the natural substrate adenosine triphosphate. Additionally, its mechanisms of action based on RNA and proofreading exonuclease inhibition, leading to the delayed RNA chain termination of infected cells, and basic pharmacological data were assessed. Additionally, the analytical determination of remdesivir and its metabolites in cells and body liquids and also some data from remdesivir use in other RNA infections—such as Ebola, Nipah virus infection, and Middle East Respiratory Syndrome (MERS)—were summarized. More recent and more detailed data on the clinical use of remdesivir in COVID-19 were reported, showing the intensive efforts of clinicians and scientists to develop a cure for this new disease. Remdesivir as such represents one of the more promising alternatives for COVID-19 therapy, however the current understanding of this disease and the possible ways of dealing with it requires further investigation.