Anthocyanin, tartaric acid, ascorbic acid of roselle flower (Hibiscus sabdariffa L.) for immunomodulatory adjuvant therapy in oral manifestation coronavirus disease-19: An immunoinformatic approach

Context: Oral manifestations that arose from COVID-19 infection often causes morbidity and systemic drug administration is less effective. Roselle flower (Hibiscus sabdariffa) is one of the plants that is often used in infusion as it gives health benefits. Hence, H. sabdariffa may benefit from adjuvant therapy to treat oral manifestation due to COVID-19. Aims: To investigate the potential of H. sabdariffa anthocyanins, tartaric acid, and ascorbic acid chemical compounds as antiviral, anti-inflammatory, antioxidant, and increasing tissue regeneration in oral manifestation due to COVID-19 infection in silico. Methods: Chemical compounds consisted of anthocyanins, (+)-tartaric acid, and ascorbic acid beside target proteins consisted of ACE2-spike, Foxp3, IL-10, IL6, IL1β, VEGF, FGF-2, HSP70, TNFR and MDA-ovalbumin were obtained from the database, ligand samples were selected through absorption, distribution, metabolism, excretion and toxicology analysis, then molecular docking simulations, identification of protein-ligand interactions, and 3D visualization were performed. Results: Anthocyanins, tartaric acid, and ascorbic acid are the active compounds in H. sabdariffa, which act as antioxidants. The activity of anthocyanin compounds is higher than other compounds through value binding affinity, which is more negative and binds to specific domains of target proteins by forming weak binding interactions that play a role in biological responses. Anthocyanins have the most negative binding energy compared to tartaric-acid and ascorbic acid. Conclusions: Anthocyanins act as antioxidants; this mechanism increases heat shock protein-70 (HSP70), which may play an important role in increasing wound regeneration of oral manifestation in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as documented in silico.