The anti-ageing potential of Rooibos (Aspalathus linearis): Preserving preadipocyte function

Abstract

Treatments with natural products rich in antioxidants have attracted remarkable interest in the cosmetic and pharmaceutical industry to combat oxidative stress and reverse the effects of ageing. Rooibos (Aspalathus linearis) is a South African fynbos plant, well-known for it's strong antioxidant capacity and use in many cosmetic products. However, little published research exists on it's potential as an anti-ageing treatment. The anti-ageing properties of fermented and unfermented Rooibos extracts were investigated using in vitro cell culture models designed to evaluate the involvement of oxidative stress and mitochondrial dysfunction. Oxidative stress was induced by depleting cellular glutathione with L- buthionine-(S,R)-sulfoximine or by exposure to H2O2 [1]. Using cell viability as an end point, protective effects of rooibos extracts were observed at 10 µg/ml. Mitochondrial DNA (mtDNA) deficient preadipocytes, 3T3-L1 ρ0, were generated following continuous long-term exposure to ethidium bromide (EtBr) [2]. Depletion of the mtDNA resulted in a significantly reduced mitochondrial membrane potential and rate of proliferation in culture, as well as an increased glucose utilization and lactate production. Treatment with the unfermented rooibos extract (100 µg/ml) stimulated cell growth and proliferation rates for both the wildtype and mutant cell lines. MtDNA depleted cells showed arrest in the G1 phase (40.9%± 1.9%) compared to wild type cells (29.8%± 2.3%), which was significantly attenuated after treatment with rooibos (36.1%± 1.6%). The results obtained indicate that rooibos extracts exhibit effects which preserve the functional capacity of preadipocytes exposed to ageing related insults.