Suppressive Effect of Garcinia kola on the Humoral Immune Response of Mice to Hepatitis B Virus Subunit Vaccine

Aim: Due to the health benefits of most medicinal plants, humans have resorted to their frequent and sometimes daily consumption, thus there is need to investigate the effect of medicinal plants consumption while on vaccination.

Study Design: This study was designed to investigate the biological interaction between Garcinia kola (GK) seed extract and Hepatitis B virus Surface Antigen.

Place and Duration of Study: The research was carried out in the Department of Pharmaceutical Microbiology and Biotechnology, University of Nigeria Nsukka, within six (6) months.

Methodology: Fresh GK seeds were obtained, identified, dried, pulverized and stored in an air-tight container until extraction. Cold maceration technique was used for extraction. Methanol was the solvent used. Locke's method of acute toxicity testing was used to ascertain the toxicity of the extract. Afterwards, the experimental animals were grouped and vaccinated accordingly. After vaccination, sera collected from the animals were used for immunogenicity studies while the whole blood was used for total white blood cell count. During the study period, the experimental animals were monitored frequently and weighed.

Results: The percentage yield after extraction was 16.7%. The extract was non-toxic up to 5000 mg/kg. The vaccination induced antibody responses (IgM, IgG1 and IgA) in all the groups but the response in the hepatitis B vaccine group was significantly higher than that of the hepatitis B vaccine/GK extract combination group (P<0.05), suggesting an inhibitory/ suppressive effect of G. kola on immune response to the hepatitis B surface antigen. The total white blood cell count equally revealed a suppressive effect of the extract on the hepatitis B virus surface antigen. The periodic weight monitoring reveals similar growth pattern across all other groups except the hepatitis B vaccine/GK combination group that seems not to be growing rapidly.

Conclusion: The outcome of this present study shows that at ≥250 mg/kg body weight GK seed extract demonstrates a suppressive effect on the immunogenic responses to hepatitis B surface antigen. Therefore, cautious consumption or total abstinence from GK is adviced in subjects receiving hepatitis B vaccination.