In silico and in vitro evaluation of silibinin: a promising anti-Chikungunya agent

• Published in: In vitro cellular & developmental biology. Animal Vol. 58; no. 3; pp. 255 - 267
• Main Authors: Dutta, Sudip Kumar, Sengupta, Siddhartha, Tripathi, Anusri
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.03.2022; Society for In Vitro Biology
• Subjects: Animal Genetics and Genomics; Animals; Antiviral activity; Antiviral Agents - chemistry; Antiviral Agents - pharmacology; Antiviral Agents - therapeutic use; Assaying; Biomedical and Life Sciences; Cell Biology; Cell Culture; Chikungunya Fever - drug therapy; Chikungunya virus; Chlorocebus aethiops; Computer applications; Cytotoxicity; Developmental Biology; Drug dosages; Glycoproteins; Infections; Life Sciences; Molecular docking; Molecular Docking Simulation; Morbidity; NSP4 protein; Silibinin; Silybin - pharmacology; Statistical analysis; Stem Cells; Toxicity; Vector-borne diseases; Vero Cells; Virus Replication; Viruses; Antiviral agents; In vitro; Silibinin; Molecular docking; Chikungunya virus
• ISSN: 1071-2690; 1543-706X
• DOI: 10.1007/s11626-022-00666-x

Chikungunya virus (CHIKV) infection and subsequent high patient morbidity is a global threat. The present study aimed to identify the potent antiviral agent against Chikungunya virus, with minimum in vitro cytotoxicity. CHIKV nsP4 3D structure was determined using the I-TASSER server followed by its refinement and pocket determination. Furthermore, high-throughput molecular docking was employed to identify candidate CHIKV nsP4 inhibitors in a library containing 214 compounds. The top ranked compound was evaluated further with various assays, including cytotoxicity, antiviral activity, time of drug addition, viral entry attachment, and microneutralization assays. High-throughput computational screening indicated silibinin to have the best interaction with CHIKV nsP4 protein, immature and mature glycoproteins with highest negative free binding energy, − 5.24 to − 5.86 kcal/mol, and the lowest inhibitory constant, 50.47 to 143.2 µM. Further in vitro analysis demonstrated silibinin could exhibit statistically significant ( p  < 0.05) dose-dependent anti-CHIKV activity within 12.5–100-µM concentrations with CC 50 as 50.90 µM. In total, 50 µM silibinin interfered with both CHIKV attachment (75%) and entry (82%) to Vero cells. Time of addition assay revealed silibinin interfered with late phase of the CHIKV replication cycle. Microneutralization assay revealed that silibinin could inhibit clearing of 50% Vero cell monolayer caused by CHIKV-induced CPE at a minimum dose of 25 µM. These data indicated silibinin to be a promising candidate drug against CHIKV infection.