New Insights on Acanthus ebracteatus Vahl: UPLC-ESI-QTOF-MS Profile, Antioxidant, Antimicrobial and Anticancer Activities

This study investigated the antioxidant, antimicrobial, anticancer, and phytochemical profiling of extracts from the leaves and stem/root of Acanthus ebracteatus (AE). The total phenolic content (TPC), total flavonoid content (TFC), 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical-scavenging activity, 2, 2′-azino-Bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical-scavenging activity, metal chelating activities (MCA), ferric reducing antioxidant power (FRAP) and oxygen radical antioxidant capacity (ORAC) were used for antioxidant assessment. The ethanolic extracts of the leaves (AEL-nor) and stem/root (AEWP-nor) without chlorophyll removal and those with chlorophyll removal, using sedimentation process (AEL-sed and AEWP-sed), were prepared. Generally, AEL-sed showed the highest antioxidant activity (FRAP: 1113.2 µmol TE/g; ORAC: 11.52 µmol TE/g; MCA: 47.83 µmol EDTA/g; ABTS 67.73 µmol TE/g; DPPH 498.8 µmol TE/g; TPC: 140.50 mg/GAE g and TFC: 110.40 mg/CE g) compared with other extracts. Likewise, AEL-sed also showed the highest bacteriostatic (MIC) and bactericidal (MBC) effects, as well as the highest anticancer and antiproliferative activity against oral squamous carcinoma (CLS-354/WT) cells. UPLC-ESI-QTOF/MS analysis of AEL-sed and AEWP-sed tentatively identified several bioactive compounds in the extracts, including flavonoids, phenols, iridoids, and nucleosides. Our results provide a potentially valuable application for A. ebracteatus, especially in further exploration of the plant in oxidative stress-related disorders, as well as the application of the plant as potential nutraceuticals and cosmeceuticals.

Virtual screening of phytochemicals by targeting multiple proteins of severe acute respiratory syndrome coronavirus 2: Molecular docking and molecular dynamics simulation studies

OBJECTIVE

Medicinal herbs are being investigated for medicationhg development against SARS-CoV-2 as a rich source of bioactive chemicals. One of the finest approaches for finding therapeutically effective drug molecules in real time is virtual screening scheme such as molecular docking in conjunction with molecular dynamics (MD) simulation. These virtual techniques provide an ample opportunity for the screening of plausible inhibitors of SARS-CoV-2 different target proteins from a comprehensive and extensive phytochemical library. The study was designed to identify potential phytochemicals by virtual screening against different receptor proteins.

METHODS

In the current study, a library of plant secondary metabolites was created by manually curating 120 phytochemicals known to have antimicrobial as well as antiviral properties. In the current study, different potential phytochemicals were identified by virtual screening against various selected receptor proteins (i.e., viral main proteases, RNA-dependent RNA polymerase (RdRp), ADP ribose phosphatase, nonstructural proteins NSP7, NSP8, and NSP9) which are key proteins responsible for transcription, replication and maturation of SARS-CoV-2 in the host. Top three phytochemicals were selected against each viral receptor protein based on their best S-scores, RMSD values, molecular interactions, binding patterns and drug-likeness properties.

RESULTS

The results of molecular docking study revealed that phytochemicals (i.e., baicalin, betaxanthin, epigallocatechin, fomecin A, gallic acid, hortensin, ichangin, kaempferol, limonoic acid, myricetin hexaacetat, pedalitin, quercetin, quercitrin, and silvestrol) have strong antiviral potential against SARS-CoV-2. Additionally, the reported preeminent reliable phytochemicals also revealed toxicity by no means during the evaluation through ADMET profiling. Moreover, the MD simulation study also exhibited thermal stability and stable binding affinity of the pedalitin with SARS-CoV-2 RdRp and SARS-CoV-2 main protease which suggests appreciable efficacy of the lead optimization.

CONCLUSION

The biological activity and pharmacologically distinguishing characteristics of these lead compounds also satisfied as repurposing antiviral drug contenders and are worth substantial evaluation in the biological laboratory for the recommendation of being plausible antiviral drug candidates against SARS-CoV-2.