Date of Completion

2023

Document Type

Thesis

Degree Name

Bachelor of Science in Pharmacy

Keywords

Caulerpa lentillifera, Drug Induced Liver Injury, Hepatotoxicity, Juvenile Zebrafish, Isoniazid (INH)

Abstract

Background and Objectives: Tuberculosis (TB) is a chronic infection that is considered as a global health burden because of its high incidence, prolonged medical treatment, drug resistance, and possibility for co-infections. The most widely used anti-TB medication used for prophylaxis, naive cases, and even drug-resistant types is isoniazid (INH) alone or in combination with other drugs. Isoniazid is known to complicate the treatment of TB infections due to its hepatotoxicity especially during prolonged and continued use. Drug-induced liver injury (DILI) resulting from chronic use of certain drugs including INH is a growing problem in drug therapy because this can decrease the effectiveness of these drugs or enhance their toxicity. This study aimed to evaluate the hepatoprotective activity of the methanol extract of Caulerpa lentillifera against INHinduced hepatotoxicity in juvenile zebrafish.

Methods: The concentration of INH was determined through a preliminary testing where mortality rates of zebrafish were determined from 5 µM to 25 µM. Then, ten (10) zebrafish were randomly selected into various treatment groups. These were exposed to DMSO, N-acetylcysteine (NAC), C. lentillifera extracts (5-10 µg/mL), INH (5 µM), and combinations of INH and NAC or extracts for 72 hours. Zebrafish mortality was monitored and evaluated at regular intervals (12–24 hrs). Serum alanine transaminase (ALT) and serum aspartate transaminase (AST) were determined from blood collected through caudal incision and centrifugation. A colorimetric method based on reaction of pyruvate with 2,4-dinitrophenylhydrazine was used to quantify the ALT and AST.

Results: Mortality rates of zebrafish increased in INH-treatment groups from 24 hours post-exposure (hpe) to 72 hpe. Treatment with NAC or extract at any concentration level did not result in significant zebrafish deaths. However, treatment of INH with NAC or 5 µg/mL extract resulted in total deaths at 48 hpe, and treatment of INH with 5 µg/mL extract resulted in total deaths at 24 hpe. ALT and AST levels showed inconclusive results from all treatment groups.

Conclusion and Recommendation: C. lentillifera showed minimal protection from zebrafish mortality due to acute INH toxicity. Because no significant elevations in ALT nor AST were observed after exposure to INH, zebrafish mortality might have been caused by acute toxic effects independent of hepatotoxicity. In addition, the presence of the extract might have caused increased levels of toxic INH metabolites. Because INH is metabolized by the CYP450 pathway to hepatotoxic hydrazine, mechanisms of druginduction by C. lentillifera could be further investigated in future studies.

First Advisor

Sigfredo B. Mata

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