Phenolic Profile of Herbal Infusion and Polyphenol-Rich Extract from Leaves of the Medicinal Plant Antirhea borbonica: Toxicity Assay Determination in Zebrafish Embryos and Larvae

Abstract

Antirhea borbonica (A. borbonica) is an endemic plant from the Mascarene archipelago in the Indian Ocean commonly used in traditional medicine for its health benefits. This study aims (1) at exploring polyphenols profiles from two types of extracts—aqueous (herbal infusion) and acetonic (polyphenol rich) extracts from A. borbonica leaves—and (2) at evaluating their potential toxicity in vivo for the first time. We first demonstrated that, whatever type of extraction is used, both extracts displayed significant antioxidant properties and acid phenolic and flavonoid contents. By using selective liquid chromatography–tandem mass spectrometry, we performed polyphenol identification and quantification. Among the 19 identified polyphenols, we reported that the main ones were caffeic acid derivatives and quercetin-3-O-rutinoside. Then, we performed a Fish Embryo Acute Toxicity test to assess the toxicity of both extracts following the Organisation for Economic Cooperation and Development (OECD) guidelines. In both zebrafish embryos and larvae, the polyphenols-rich extract obtained by acetonic extraction followed by evaporation and resuspension in water exhibits a higher toxic effect with a median lethal concentration (LC50: 5.6 g/L) compared to the aqueous extract (LC50: 20.3 g/L). Our data also reveal that at non-lethal concentrations of 2.3 and 7.2 g/L for the polyphenol-rich extract and herbal infusion, respectively, morphological malformations such as spinal curvature, pericardial edema, and developmental delay may occur. In conclusion, our study strongly suggests that the evaluation of the toxicity of medicinal plants should be systematically carried out and considered when studying therapeutic effects on living organisms.

Caffeic Acid, One of the Major Phenolic Acids of the Medicinal Plant Antirhea borbonica, Reduces Renal Tubulointerstitial Fibrosis

“…Based on our previous study [ 32 ], the dose of 25 mg/kg was chosen for mice gavage and corresponded to the lowest dose (1.4 g/L) tested on the zebrafish (embryos/larvae) model, showing no toxicological effect. As shown in Figure 1 A, the quantity of polyphenol administered by gavage is not negligible since we found total contents of phenolic acids and flavonoids of 47.6 ± 8.5 mg GAE/100 g dried powder and of 27.1 ± 3.2 mg QE/100 g dried powder, respectively.…”

“…We have previously reported [ 32 ] that CA and derivatives were the most abundant polyphenolic compounds of A. borbonica . In order to explore the mechanism of action of polyphenol-rich extract from A. borbonica , we investigated if we could reproduce the observed curative nephroprotective effects of A. borbonica extract by oral administration of CA.…”

“…However, to the best of our knowledge, the oral administration of the CA molecule has never been studied in the UUO model. Since CA is the main phenolic acid found in A. borbonica [ 32 ], to properly investigate if CA participates in the antioxidant and anti-fibrotic effects observed with the polyphenol-rich extract from A. borbonica , we had to study the effect of oral administration of CA in the representative UUO renal tubulointerstitial fibrosis model. Our results clearly show that oral administration for 5 days of CA (25 mg/kg), 3 days after UUO, significantly decreased macrophage infiltration, myofibroblast appearance and extracellular matrix accumulation.…”

“…However, regarding A. borbonica, to the best of our knowledge, no in vivo preclinical study investigating a putative nephroprotective effect has been reported. We have recently reported a detailed (qualitative and quantitative) phenolic profile as well as the antioxidant activity of aqueous and organic extracts of A. borbonica and determined the LC 50 of both extracts on a zebrafish embryos model [ 32 ] according to the OECD (Organisation for Economic Co-operation and Develpoment) guidelines, allowing us to safely investigate in vivo the effect of A. borbonica in a kidney disease context.…”

“…Because of the potential therapeutic interest of A. borbonica against renal tubulointerstitial fibrosis, but also because we have previously reported [ 32 ] that the main polyphenols of A. borbonica was caffeic acid (CA) and since it is now well admitted that the absorption of CA derivatives results in free CA as secondary metabolites [ 33 ], the aims of our study were (i) to look for the presence of nephrotoxic molecules, (ii) to evaluate the renal antifibrotic effect of A. borbonica as well as CA in the in vivo unilateral ureteral obstruction (UUO) mouse model and (iii) to investigate the presence of putative specific antifibrotic molecules from A. borbonica at the renal tissue level.…”