# Opuntia ficus-indica (L.) Mill. Extract: From Chemical Characterization to Inflammatory Profiling and Its Potential Effects in a Zebrafish Model of Spinal Cord Injury—A Morphological and Molecular Study

## TL;DR

This study explores the potential of unripe Opuntia ficus-indica fruit extract to aid in spinal cord injury recovery by analyzing its chemical makeup and effects in a zebrafish model.

## Contribution

The study is the first to investigate the effects of unripe Opuntia ficus-indica extract on spinal cord injury using a zebrafish model and molecular profiling.

## Key findings

- The extract contains 14 secondary metabolites, primarily flavonoids and phenylpropanoid acids.
- Non-toxic concentrations of the extract improved locomotor recovery in zebrafish spinal cord injury models.
- The extract modulated inflammation and neurogenesis-related pathways, including reduced pro-inflammatory cytokines and increased BDNF and Sonic Hedgehog signaling.

## Abstract

Natural compounds are increasingly explored for their ability to modulate multiple molecular pathways involved in inflammation and oxidative stress and for their therapeutic potential. Among these, Opuntia ficus-indica (L.) Mill. has attracted growing interest due to its rich phytochemical profile; however, the biological properties of unripe fruits remain largely unexplored. In this study, a hydroalcoholic extract obtained from unripe O. ficus-indica fruits was characterized for its chemical composition, antioxidant capacity, and concentration-dependent embryotoxic profile and subsequently investigated in a zebrafish model of spinal cord injury (SCI). UHPLC-HRMS/MS analysis identified 14 secondary metabolites, mainly flavonoids and phenylpropanoid acids. Antioxidant activity was confirmed by DPPH and ABTS assays. An embryotoxicity assessment conducted according to OECD Test Guideline 236 revealed no mortality at concentrations below 100 µg mL−1 and an LC50 of 323.59 µg mL−1 at 96 h post-fertilization, allowing the identification of non-toxic concentrations for subsequent in vivo experiments. Based on these results, the extract was tested in a larval zebrafish SCI transection model. Treated larvae showed improved locomotor recovery, particularly under continuous exposure, accompanied by modulation of molecular pathways involved in inflammation, neurotrophic support, and neurogenesis, including reduced pro-inflammatory cytokine expression and increased BDNF and Sonic Hedgehog signaling markers. Overall, these findings expand current knowledge on unripe O. ficus-indica and highlight its potential to modulate molecular pathways involved in SCI-induced damage and repair.