# Fermented and Unfermented Rooibos (Aspalathus linearis) Exhibit Selective Protection Against Hepatic Stress in Rats Exposed to Fumonisin B1

## TL;DR

Rooibos tea, both fermented and unfermented, helps reduce liver stress in rats exposed to a harmful toxin, but doesn't fully protect the liver.

## Contribution

The study reveals distinct protective effects of fermented and unfermented rooibos against fumonisin B1-induced liver stress in rats.

## Key findings

- Both rooibos extracts reduced oxidative damage and modulated stress regulators in rats exposed to fumonisin B1.
- Fermented rooibos uniquely increased glutathione peroxidase and decreased IL-1β, while unfermented rooibos enhanced Nrf2 and Sirt3.
- Neither extract fully restored liver phospholipid profiles or serum cholesterol altered by fumonisin B1.

## Abstract

Daily exposure to high doses of fumonisin B1 (FB1) induced liver toxicity, wherein the oxidation, mitochondrial, and cellular stress markers were elevated; inflammatory markers and serum enzyme activities were heightened; and phospholipid acyl chain composition was distorted, while histopathological modifications were not substantially severe.

Rooibos extracts compacted the FB1 toxic effect by facilitating the antioxidant state (increased glutathione peroxidase) and decreasing both levels of malondialdehyde and protein carbonyls.

Rooibos extract administration also enhanced mitochondrial responses (Nrf2, SOD2, PGC1-α, and Sirt-3), while decreasing the cytokine IL-1β and the cellular stress marker HSP70.

Rooibos extracts did not suppress FB1-induced hepatocellular lipids’ distortions, nor serum enzyme activities.

Efficacy variability between rooibos extracts (fermented and unfermented) is attributed to their different polyphenolic contents and capacities.

The exploration of natural redox-modulating agents to mitigate/reduce oxidative damage triggered by toxins is a major area of interest in nutritional and pharmacological fields. Aspalathus linearis (rooibos), traditionally consumed in South Africa for health benefits, was assessed for hepatoprotective effects against fumonisin B1 (FB1)-induced damage. This study involved 24 male rats (n = 6/group) that received FB1 (50 mg/kg diet equivalent, i.p. for 5 days) with or without oral exposure to unfermented (GR) or fermented (FR) rooibos extracts. Alongside somatic records, we assessed blood biochemicals, as well as liver histology, antioxidative stress markers (GSH, GPx, MDA, and carbonylation), regulatory proteins (Nrf2, Sirt3, PGC-α, TRX1, HSP70, and LONp1), inflammation (cytokines), and phospholipid fatty acid profile. Based on results, FB1 suppressed growth, compromised liver function, altered redox status, and elevated stress markers. Both rooibos extracts decreased oxidative damage (↓MDA, ↓carbonylation) and modulated stress regulators (↑Nrf2, ↓HSP70). FR uniquely increased GPx and TRX1 while decreasing IL-1β and PGC-α concentrations, whereas GR strongly increased Nrf2 and Sirt3, reflecting distinct bioactivities linked to their differing polyphenolic profiles. Neither extract compensated for FB1-induced alterations in the liver total phospholipid fatty acid profile or serum cholesterol. In conclusion, GR and FR improved redox potential and inflammatory/stress response; however, this effect was selective, as it did not translate into comprehensive hepatoprotection. These findings support the potential role of rooibos as a dietary modulator of endogenous antioxidant defenses, although clinical translational trials are needed.