Khaya grandifoliola C.DC: a potential source of active ingredients against hepatitis C virus in vitro

• Published in: Archives of virology 2016-05, Vol.161 (5), p.1169-1181
• Main Authors: Galani, Borris Rosnay Tietcheu, Sahuc, Marie-Emmanuelle, Sass, Gabriele, Njayou, Frédéric Nico, Loscher, Christine, Mkounga, Pierre, Deloison, Gaspard, Brodin, Priscille, Rouillé, Yves, Tiegs, Gisa, Séron, Karin, Moundipa, Paul Fewou
• Format: Article
• Language: English
• Subjects: Antiviral Agents - isolation & purification; Antiviral Agents - pharmacology; Biochemistry; Biomedical and Life Sciences; Biomedicine; Carcinoma, Hepatocellular - metabolism; Cell Line, Tumor; Chromatography; Chromatography, Gel - methods; Cytotoxicity; Dose-Response Relationship, Drug; FDA approval; Fluorescent Antibody Technique; Gas Chromatography-Mass Spectrometry - methods; Hepacivirus - drug effects; Hepatitis C; Hepatitis C virus; Humans; Infections; Infectious Diseases; Khaya; Life Sciences; Liver Neoplasms - metabolism; Mass spectrometry; Medical Microbiology; Meliaceae; Meliaceae - chemistry; Microbiology and Parasitology; Original Article; Plant Bark - chemistry; Plant Extracts - isolation & purification; Plant Extracts - pharmacology; Scientific imaging; Virology; Virus Internalization - drug effects; Virus Replication - drug effects
• ISSN: 0304-8608; 1432-8798
• DOI: 10.1007/s00705-016-2771-5

In this study, we examined the antiviral properties of Khaya grandifoliola C.DC (Meliaceae) on the hepatitis C virus (HCV) life cycle in vitro and identified some of the chemical constituents contained in the fraction with the most antiviral activity. Dried bark powder was extracted by maceration in a methylene chloride/methanol (MCM) system (50:50; v/v) and separated on silica gel by flash chromatography. Infection and replication rates in Huh-7 cells were investigated by luciferase reporter assay and indirect immunofluorescence assay using subgenomic replicons, HCV pseudotyped particles, and cell-culture-derived HCV (HCVcc), respectively. Cell viability was assessed by MTT assay, and cellular gene expression was analysed by qRT-PCR. The chemical composition of the fraction with the most antiviral activity was analysed by coupled gas chromatography and mass spectrometry (GC-MS). Five fractions of different polarities (F0-F100) were obtained from the MCM extract. One fraction (KgF25) showed the strongest antiviral effect on LucUbiNeoET replicons at nontoxic concentrations. Tested at 100 µg/mL, KgF25 had a high inhibitory effect on HCV replication, comparable to that of 0.01 µM daclatasvir or 1 µM telaprevir. This fraction also inhibited HCVcc infection by mostly targeting the entry step. KgF25 inhibited HCV entry in a pan-genotypic manner by directly inactivating free viral particles. Its antiviral effects were mediated by the transcriptional upregulation of the haem oxygenase-1 gene and interferon antiviral response. Three constituents, namely, benzene, 1,1′-(oxydiethylidene)bis (1), carbamic acid, (4-methylphenyl)-, 1-phenyl (2), and 6-phenyl, 4-(1′-oxyethylphenyl) hexene (3), were identified from the active fraction KgF25 by GC-MS. Khaya grandifoliola contains ingredients capable of acting on different steps of the HCV life cycle.