Insights into Asparaginase from Endophytic Fungus Lasiodiplodia theobromae: Purification, Characterization and Antileukemic Activity.

Endobiotic fungi are considered as a reservoir of numerous active metabolites. Asparaginase is used as an antileukemic drug specially to treat acute lymphoblastic leukaemia. The presented study aims to optimize the media conditions, purify, characterize, and test the antileukemic activity of the asparaginase induced from Lasiodiplodia theobromae. The culture medium was optimized using an experiment designed by The Taguchi model with an activity ranging from 10 to 175 IU/mL. Asparaginase was induced with an activity of 315 IU/mL. Asparaginase was purified with a specific activity of 468.03 U/mg and total activity of 84.4 IU/mL. The purified asparaginase showed an approximate size of 70 kDa. The purified asparaginase showed an optimum temperature of 37 °C and an optimum pH of 6. SDS reduced the activity of asparaginase to 0.65 U/mL while the used ionic surfactants enhanced the enzyme activity up to 151.92 IU/mL. The purified asparaginase showed a Km of 9.37 µM and Vmax of 127.00 µM/mL/min. The purified asparaginase showed an IC50 of 35.2 ± 0.7 IU/mL with leukemic M-NFS-60 cell lines and CC50 of 79.4 ± 1.9 IU/mL with the normal WI-38 cell line. The presented study suggests the use of endophytic fungi as a sustainable source for metabolites such as asparaginase, provides an opportunity to develop a facile, eco-friendly, cost-effective, and rapid synthesis of antileukemic drugs, which have the potential to be used as alternative and reliable sources for potent anticancer agents.

A Comprehensive Review about the Molecular Structure of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): Insights into Natural Products against COVID-19.

In 2019, the world suffered from the emergence of COVID-19 infection, one of the most difficult pandemics in recent history. Millions of confirmed deaths from this pandemic have been reported worldwide. This disaster was caused by SARS-CoV-2, which is the last discovered member of the family of Coronaviridae. Various studies have shown that natural compounds have effective antiviral properties against coronaviruses by inhibiting multiple viral targets, including spike proteins and viral enzymes. This review presents the classification and a detailed explanation of the SARS-CoV-2 molecular characteristics and structure-function relationships. We present all currently available crystal structures of different SARS-CoV-2 proteins and emphasized on the crystal structure of different virus proteins and the binding modes of their ligands. This review also discusses the various therapeutic approaches for COVID-19 treatment and available vaccinations. In addition, we highlight and compare the existing data about natural compounds extracted from algae, fungi, plants, and scorpion venom that were used as antiviral agents against SARS-CoV-2 infection. Moreover, we discuss the repurposing of select approved therapeutic agents that have been used in the treatment of other viruses.