Evaluation of Polyphenol Content and Antioxidant Capacity of Aqueous Extracts from Eight Medicinal Plants from Reunion Island: Protection against Oxidative Stress in Red Blood Cells and Preadipocytes

Abstract

Background—Medicinal plants are traditionally used as infusions or decoctions for their antioxidant, anti-inflammatory, hypolipidemic and anti-diabetic properties. Purpose—The aim of the study was to define the polyphenol composition and to assess the antioxidant capacity of eight medicinal plants from Reunion Island referred to in the French Pharmacopeia, namely Aphloia theiformis, Ayapana triplinervis, Dodonaea viscosa, Hubertia ambavilla, Hypericum lanceolatum, Pelargonium x graveolens, Psiloxylon mauritianum and Syzygium cumini. Methods—Polyphenol content was assessed by biochemical assay and liquid chromatography coupled to mass spectrometry. Antioxidant capacity was assessed by measuring DPPH reduction and studying the protective effects of herbal preparation on red blood cells or preadipocytes exposed to oxidative stress. Results—Polyphenol content ranged from 25 to 143 mg gallic acid equivalent (GAE)/L for infusions and 35 to 205 mg GAE/L for decoctions. Liquid chromatography coupled to mass spectrometry analysis showed the presence of major bioactive polyphenols, such as quercetin, chlorogenic acid, procyanidin and mangiferin. Antioxidant capacity assessed by different tests, including DPPH and Human red blood cell (RBC) hemolysis of herbal preparations, demonstrated a dose-dependent effect whatever the extraction procedure. Our data suggest that decoction slightly improved polyphenol extraction as well as antioxidant capacity relative to the infusion mode of extraction (DPPH test). However, infusions displayed a better protective effect against oxidative stress-induced RBC hemolysis. Conclusion—Traditional preparations of medicinal plant aqueous extracts (infusions and decoctions) display antioxidant properties that limit oxidative stress in preadipocytes and red blood cells, supporting their use in the context of metabolic disease prevention and treatment.

Protective Effects of Medicinal Plant Decoctions on Macrophages in the Context of Atherosclerosis

“…Medicinal plant decoctions traditionally used in Reunion Island could represent the basis of new therapeutic strategies aimed at preventing or limiting the progression of atherosclerosis [ 27 , 31 ]. Many medicinal plants from Reunion Island are rich in polyphenols, and their composition is described in our previous study [ 27 ]. Among these compounds, flavonoids such as quercetin could be, at least in part, responsible for the bioactivity of these plant-based herbal teas.…”

“…All raw material was provided by HABEMUS PAPAM Industry proceeded with the following industrial process: trimming, microwave dehydration, grinding and packaging in tea bags containing 1 g of plant powder. Industrial lots and corresponding GPS coordinates are described in our previous study [ 27 ].…”

“…The tea bags were removed and the decoctions were cooled at RT before storage at −80 °C until analysis. Characterization of the polyphenol contents and antioxidant activity of the decoctions are reported in our previous study [ 27 ].…”

“…Reunion Island is a hotspot of biodiversity with 22 plants listed in the French Pharmacopeia, widely used by the population for antioxidant, lipid-lowering and anti-inflammatory properties [ 26 ]. Our previous study on eight medicinal plants used in Reunion Island revealed the presence of bioactive polyphenols (such as quercetin, gallic acid, mangiferin) and antioxidant properties on in vitro models (human red blood cells and murine preadipocytes 3T3-L1) [ 27 ]. Ethnopharmacological studies support the interest of medicinal plant antioxidant and anti-inflammatory activities in the management of different pathologies including atherosclerosis [ 28 , 29 , 30 , 31 ].…”

“…In this study, eight medicinal plant decoctions used in Reunion Island were evaluated for their possible contribution to atherosclerosis prevention and treatment: Aphloia theiformis , Ayapana triplinervis , Dodonaea viscosa , Hubertia ambavilla , Hypericum lanceolatum , Pelargonium x graveolens , Psiloxylon mauritianum and Syzygium cumini . Based on our previous study [ 27 ] reporting the composition and antioxidant effects of infusions and decoction of these eight plants, we hypothesized that the variety of polyphenols contained in these extracts could confer them interesting properties to limit the processes underlying atherogenesis. Medicinal plants with a higher polyphenol content, especially those containing quercetin, isorhamnetin, chlorogenic acid or kaempferol, could have an interesting bioactivity in this context [ 32 , 33 , 34 , 35 , 36 ].…”