Aspalathus linearis (Rooibos) Targets Adipocytes and Obesity-Associated Inflammation

Abstract

Excess weight and obesity are the fifth leading cause of death globally, and sustained efforts from health professionals and researchers are required to mitigate this pandemic-scale problem. Polyphenols and flavonoids found in Aspalathus linearis—a plant widely consumed as Rooibos tea—are increasingly being investigated for their positive effects on various health issues including inflammation. The aim of our study was to examine the effect of Rooibos extract on obesity and the associated low-grade chronic inflammatory state by testing antioxidant activity, cytokine secretions, macrophage polarization and the differentiation of human adipocytes through the development of adipospheroids. Rooibos extract significantly decreased ROS production and the secretion of pro-inflammatory cytokines (IFN-γ, IL-12, IL-2 and IL-17a) in human leukocytes. Additionally, Rooibos extract down-regulated LPS-induced macrophage M1 polarization, shown by a significant decrease in the expression of pro-inflammatory cytokines: TNFα, IL-8, IL-6, IL-1β and CXCL10. In addition, Rooibos inhibited intracellular lipid accumulation and reduced adipogenesis by decreasing the expression of PPARγ, Ap2 and HSL in adipospheroids. A significant decrease in leptin expression was noted and this, more interestingly, was accompanied by a significant increase in adiponectin expression. Using a co-culture system between macrophages and adipocytes, Rooibos extract significantly decreased the expression of all studied pro-inflammatory cytokines and particularly leptin, and increased adiponectin expression. Thus, adding Rooibos tea to the daily diet is likely to prevent the development of obesity associated with chronic low-level inflammation.

6-Gingerol Ameliorates Adiposity and Inflammation in Adipose Tissue in High Fat Diet-Induced Obese Mice: Association with Regulating of Adipokines

“…Recently, research results on food components or phytochemicals that ameliorate obesity-associated inflammation have emerged. Basil seed [36] and rooibos [37] inhibited adipogenesis and pro-inflammatory cytokine expression in vitro, and anthocyanins attenuated obesity and associated inflammation by modulating the secretion of inflammatory adipokines in several animal and clinical studies [38]. Here, we observed that HFD induced the enlargement of adipocytes and significantly increased the mRNA levels of proinflammatory adipokines, such as TNF-α, MCP-1, PAI-1, leptin, and resistin in the WAT.…”

Translation of preclinical ethnomedicine data in LMICs: the example of rooibos

“…The antioxidant capacity of rooibos also links closely to an anti-inflammatory outcome. In this context, data from in vitro models of inflammation associate rooibos administration with improved tight junction protein expression and interaction status to maintain endothelial cellular structure and barrier integrity ( Ku et al, 2015 ; Lee and Bae, 2015 ; Pretorius and Smith, 2022 ), modulation of PGE2 synthesis ( Hedbrant et al, 2022 ), inhibition of basophil activation ( Pedretti and Peter, 2020 ) and an inhibitory effect on concentrations of pro-inflammatory mediators–such as IL-1α, IL-6, IL-8, VCAM-1 and ATF4 gene expression ( Lawal et al, 2019b ), as well as IFN-γ, IL-12, IL-2, IL-17a, TNF-α, IL-8, IL-6, IL-1β and CXCL10 ( Nehme et al, 2023 )–and increased anti-inflammatory cytokine, IL-10 ( Ichiyama et al, 2007 ). In addition, the flavonoid actives aspalathin and nothofagin were reported to prevent the expression of cell adhesion molecules and transendothelial migration of neutrophils in LPS- and high glucose-exposed cells ( Ku et al, 2015 ; Lee and Bae, 2015 ), while other rooibos constituents quercetin, luteolin and chrysoeriol reportedly inhibited antigen- and calcium ionophore-stimulated degranulation in basophils ( Morishita et al, 2019 ).…”