COMPUTATIONAL SCREENING AND MOLECULAR DOCKING OF LICHEN SECONDARY METABOLITES AGAINST SEVERE ACUTE RESPIRATORY SYNDROME-COV-2 MAIN PROTEASE AND SPIKE PROTEIN

Objective: At present, the coronavirus disease (COVID)-19 pandemic is increasing global health concerns. This coronavirus outbreak is caused by severe acute respiratory syndrome coronavirus (SARS-CoV)-2. Since, no specific antiviral for treatment against COVID-19, so identification of new therapeutics is an urgent need. The objective of this study is to the analysis of lichen compounds against main protease and spike protein targets of SARS-CoV-2 using in silico approach. Methods: A total of 108 lichen compounds were subjected to ADMET analysis and 14 compounds were selected based on the ADMET properties and Lipinski’s rule of five. Molecular docking was performed for screening of selected individual lichen metabolites against the main protease and spike proteins of SARS-CoV-2 by Schrodinger Glide module software. Results: Among the lead compounds, fallacinol showed the highest binding energy value of −11.83 kcal/mol against spike protein, 4-O-Demethylbarbatic acid exhibited the highest dock score of −11.67 kcal/mol against main protease. Conclusion: This study finding suggests that lichen substances may be potential inhibitors of SARS-CoV-2.

Structure-Based Screening of Novel Lichen Compounds for SARS Coronavirus Main protease (Mpro) and Angiotensin-Converting Enzyme 2 (ACE2) inhibitory potentials as multi-target inhibitors of COVID-19

Outbreak of SARS-CoV-2 and massing death caused by it all over world has imposed great concern on scientific community to develop potential drugs to combat with Coronaviruas disease 19 ( COVID-19 ). In this regard, lichen metabolites may offer a vast reservoir for discovery of anti-viral drug candidates. Therefore to find novel compounds against COVID-19, we created a library of 412 lichen compounds and subjected to virtual screening against two molecular targets; SARS-CoV-2 target- Main protease (Mpro) and host cell target- Angiotensin-converting enzyme 2 (ACE2). All the ligands were virtually screened, and 80 compounds were found to have better docking score with both the targets. These compounds were assessed for druglikeness analysis where 27 compounds were found to fit well for redocking studies. The results of redocking by X-Score showed that 7 out of 27 compounds were found to have high affinities with Mpro as well ACE2 which reflect that these compounds can function as dual inhibitors. Molecular docking, druglikeness, X-Score and toxicity analysis resulting seven novel lichen compounds (Orcinyllecanorate, Siphulin, Fremontol, Gyrophoric acid, Rhizocarpic acid, Ovoic acid, and Umbilicaric acid) with Mpro and ACE2 multi-target activities and they can be used as hit compounds to develop potential antiviral agents against SARS-CoV-2. These lichen compounds may be a suitable candidate for further experimental analysis.

Potential of Lichen Compounds as Antidiabetic Agents with Antioxidative Properties: A Review

The advancement in the knowledge of potent antioxidants has uncovered the way for greater insight in the treatment of diabetic complications. Lichens are a rich resource of novel bioactive compounds and their antioxidant potential is well documented. Herein we review the antidiabetic potential of lichens which have received considerable attention, in the recent past. We have correlated the antidiabetic and the antioxidant potential of lichen compounds. The study shows a good accordance between antioxidant and antidiabetic activity of lichens and points out the need to look into gathering the scarce and scattered data on biological activities for effective utilization. The review establishes that the lichen extracts, especially ofParmotremasp. andRamalinasp. have shown promising potential in both antidiabetic and antioxidant assays. Ubiquitous compounds, namely, zeorin, methylorsellinate, methyl-β-orcinol carboxylate, methyl haematommate, lecanoric acid, salazinic acid, sekikaic acid, usnic acid, gyrophoric acid, and lobaric acid have shown promising potential in both antidiabetic as well as antioxidant assays highlighting their potential for effective treatment of diabetic mellitus and its associated complications. The available compilation of this data provides the future perspectives and highlight the need for further studies of this potent herbal source to harvest more beneficial therapeutic antidiabetic drugs.