EP_091. Cardiotoxicity assessment of Hibiscus sabdariffa L.-derived product, Sí Roja, in zebrafish embryos

Chin Long Poo¹, Mohd Rahimi Ashraf Abd Rahman¹, Norizah Awang¹, Nik Aina Syazana Nik Zainuddin¹, Nur Liana Md Nasir¹, Mei Siu Lau¹, Siti Khadijah Mustapha Kamal¹, Siti Soleha Ab Dullah¹, Maizatul Hasyima Omar¹, Hussin Muhammad^1*

1. Herbal Medicine Research Centre, Institute for Medical Research, National Institutes of Health, Ministry of Health Malaysia, Setia Alam, 40170 Shah Alam, Selangor, Malaysia

*Corresponding author: Hussin Muhammad. This email address is being protected from spambots. You need JavaScript enabled to view it.

ABSTRACT

INTRODUCTION: Hibiscus sabdariffa L., commonly known as roselle, has shown potential benefits for antioxidant and cardiovascular health. However, the cardiotoxic potential of its derived products, SÍ Roja, remains poorly understood. Zebrafish (Danio rerio) embryos serve as a valuable in vivo model for cardiotoxicity screening due to their transparent bodies and rapid heart development.

OBJECTIVE(S): This study aimed to evaluate the effects of SÍ Roja on embryonic cardiac function in zebrafish, focusing on heartbeat rate as an early indicator of cardiotoxicity.

MATERIALS & METHODS: Zebrafish embryos were exposed to SÍ Roja at concentrations of 5, 10, 20, 40, and 80 mg/L from 6 hours post-fertilisation (hpf), following OECD Test Guideline 236. Heartbeats were assessed at 72 hpf under a stereomicroscope and quantified in beats per minute (bpm) via video analysis. Internal and negative control groups were included. Data were then analysed in GraphPad Prism using one-way ANOVA with post-hoc Dunnett’s test.

RESULTS: Cardiac evaluations revealed altered heart rates, initially increasing and then decreasing at elevated concentrations. A significant increase in heartbeat was observed at 5 mg/L compared to the negative control (p < 0.0001), indicating a cardiostimulatory effect. The heartbeat decreased steadily after 10 mg/L and showed a dose-dependent decrease in heart rate from 20 to 40 mg/L, suggesting cardiotoxicity. The decreased heartbeat rate observed in all surviving embryos at 40 mg/L suggested that higher concentrations may cause cardiotoxicity.

CONCLUSION: SÍ Roja demonstrated dual, dose-dependent effects on zebrafish embryonic cardiac function—cardiostimulatory at low concentrations and cardiotoxic at higher concentrations. These findings highlight the importance of dose consideration when evaluating the safety and therapeutic potential of H. sabdariffa L.-derived products during early development.

KEYWORDS: Hibiscus sabdariffa, Zebrafish, Cardiotoxicity, Heartbeat Rate, Herbal Safety