Plant-derived compounds have long been used to treat wounds, inflammation and metabolic diseases, due to their broad biological activities making them valuable candidates for new therapies. Réunion Island has numerous medicinal plants listed in the French pharmacopoeia but limited information exists on their chemical composition and biological effects.

This study focused on 11 traditional medicinal plants from Réunion Island (Antirhea borbonica, Aphloia theiformis, Ayapana triplinervis, Coffea mauritiana, Dodonaea viscosa, Hypericum lanceolatum, Nuxia verticillata, Olea europaea, Psiloxylon mauritianum, Syzygium cumini, and Vepris lanceolata). We aimed to evaluate the in vivo toxicity of the aqueous extracts of these medicinal plants and assess their biological effects using zebrafish models.

Polyphenol concentrations and compositions were determined using the Folin-Ciocalteu colorimetric assay and liquid chromatography-mass spectrometry. The total polyphenol content ranged from 103.2 to 14.2 mg GAE/g dried plant and the main identified compounds included chlorogenic acid, gallic acid, quercetin, kaempferol, and mangiferin. Toxicity assays allowed the determination of the maximum non-toxic concentration (MNTC) for each extract. At these concentrations, several extracts showed beneficial effects on inflammation, tissue repair, and lipid accumulation.

This work presents the first comprehensive analysis of the composition and in vivo activity of these 11 Reunionese medicinal plants. It demonstrates the therapeutic value of such extracts in managing oxidative stress, enhancing regeneration, modulating immune responses, and reducing lipid accumulation in vivo. Hypericum lanceolatum and Ayapana triplinervis appeared as particularly promising. These findings support further exploration of plant-based strategies for treating chronic and metabolic diseases and their complications in a preventive/therapeutic approach.