Effet de l’extrait ethanolique d’aframomum angustifolium et de ses fractions sur le stress oxydant et le microbiote intestinal induit par l’eau oxygénée chez le rat.

Abstract

Oxidative stress has been associated with the development of various pathologies such as the alteration of the intestinal microbiota, cancer, cardiovascular diseases and diabetes. The aim of this study was to compare the in vitro and in vivo antioxidant properties and the effect on the intestinal microbiota of the ethanolic extract of Aframomum angustifolium seeds and its fractions. The content of total phenolic compounds, flavonoids and alkaloids was determined by colorimetric methods. The total antioxidant capacity, reducing power and ABTS+ radical scavenging capacity were used to determine the in vitro antioxidant potential of the ethanolic extract and its fractions. For the in vivo study, male wistar rats weighing between 180-200g were subdivided into 2 batches of rats, batch 1 of 05 rats representing the negative control group (TN) which received distilled water and batch 2 (25 rats) which were stressed by intraperitoneal injection with hydrogen peroxide at a single dose of 2ml/kg bw of 3% hydrogen peroxide, then subdivided into 05 groups of 05 rats: a positive control (PC) group receiving distilled water, an EEA group receiving 300 mg/kg bw of the ethanolic extract, two FDCM and FMETH groups receiving 150 mg/kg bw of the dichloromethane and methanol fractions respectively and a reference group receiving 10 mg/kg bw of vitamin E. After 14 days of treatment, the animals were sacrificed after anaesthesia. Plasma, homogenates (liver, heart, kidney) and haemolysate were then prepared for the determination of biochemical parameters (NO● radical, malondialdehyde, catalase, superoxide dismutase, glutathione) using colorimetric methods, and intestinal contents were sampled for bacterial quantification. The results showed that the methanol fraction contained the highest levels of phenolic compounds, flavonoids and alkaloids. The ethanolic extract showed the best total antioxidant capacity and the fractions showed a better capacity to inhibit the ABTS+ radical and a better reducing power compared to the ethanolic extract. In vivo, the extract was better at reducing malondialdehyde and the fractions were better at reducing NO●. In terms of antioxidant markers, the fractions increased the activity of catalase, superoxide dismutase and glutathione levels compared with the ethanolic extract. The methanol fraction had a beneficial effect on bacteroids and clostridioles. Principal component analysis showed that the methanol fraction had the best associations with oxidative stress parameters.