Kouam Arnaud - Department of Biomedical Sciences Faculty of Health Sciences University of Buea South West Region, Buea, Cameroon
Njayou Frédéric Nico - Laboratory of Pharmacology and Toxicology, Department of Biochemistry, Faculty of Science, University of Yaoundé ۱, PO Box ۸۱۲, Yaoundé, Cameroon
Yuan Fei - CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing ۱۰۰۱۰۱, China
Babayemi Oladejo - Department of Microbiology, Federal University of Technology, P.M.B ۷۰۴, Akure, Ondo State, Nigeria
He Hongtao - CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing ۱۰۰۱۰۱, China
Mkounga Pierre - Laboratory of Physical Chemistry and Phytochemistry, Department of Organic Chemistry, University of Yaoundé ۱, PO Box ۸۱۲, Yaoundé, Cameroon
Moundipa Paul - Laboratory of Pharmacology and Toxicology, Department of Biochemistry, Faculty of Science, University of Yaoundé ۱, PO Box ۸۱۲, Yaoundé, Cameroon

Objective: A fraction from Khaya grandifoliola has recently been shown to inhibit hepatitis C virus (HCV) infection and three limonoids (۱۷-epi-methyl-۶-hydroxylangolensate, ۷-deacetoxy-۷-oxogedunin and ۷-deacetoxy-۷R-hydroxygedunin) were purified from this fraction. The present study aimed at assessing the inhibitory effect of these limonoids on HCV using cell-culture derived HCV (HCVcc) system. Materials and Methods: Cytotoxic effects of the limonoids on Huh۷.۵ cells were assessed by MTT assay. Huh۷.۵ cells were transfected with RNA transcripts of the plasmid Jc۱/GLuc۲a, carrying a Gaussia luciferase reporter gene to rescue the HCVcc particles which were used to infect naïve cells in the presence or absence of the studied limonoids during ۷۲ hr. Infection and replication rates were monitored by luciferase reporter assay and immunofluorescence assay (IFA) while cellular gene expression was analyzed by western blot, respectively. Results: The limonoids inhibited HCV infection mostly by targeting entry and replication stage. Their inhibitory effect on entry step, comparable to that of anti-CD۸۱ antibody, was related to the blocking of CD۸۱ receptor. In the replication step, the limonoids decreased the expression of NS۵B similar to danoprevir. These compounds also significantly decreased but up-regulated the expression of Class-III phosphatidylinositol ۴-kinase alpha and ۲’,۵’-oligoadenylate synthase-۳, respectively. Conclusion: The present findings suggest that limonoids from K. grandifoliola are potential anti-HCV agents and may offer an advantage in the treatment of HCV infection.

Khaya grandifoliola, Limonoids, Anti-HCV infection, Class III phosphatidylinositol ۴-kinase alpha, ۲’,۵’- oligoadenylate synthase-۳