For cell culture, a concentrated solution of the freeze-dried rooibos HWSS (100 mg/ml) was prepared in tissue culture-grade water, where after a 1 mg/ml stock was made in culture medium (adipocyte differentiation medium or adipocyte maintenance medium).
3T3-L1 preadipocytes were differentiated in the presence and absence of the rooibos HWSS. Cells were chronically exposed to rooibos for 9 days (day 8), with medium supplemented with the rooibos HWSS being changed daily.
All compounds were present at 1.4 mg/g of the HWSS (freeze-dried infusion) or higher (Table 2), except ferulic acid and luteolin-7-O-glucoside that were not present at detectable levels.
Type Compound Soluble solids Infusion (mg/g) (mg/l) Phenylpropenoid PPAG(b) 6.30 9.54 Dihydrochalcone Aspalathin 3.67 5.56 Nothofagin 0.64 0.97 Flavone Isoorientin 14.44 21.88 Orientin 8.62 13.06 Vitexin 1.91 2.89 Isovitexin 2.29 3.47 Flavonol Qucrcetin-3-O-robinobioside 10.24 15.51 Hyperoside 2.91 4.41 Rutin 2.31 3.50 Isoquercitrin 1.38 2.09 HWSS(a) 515.00 (a) HWSS, hot water soluble solids in fermented rooibos, extracted during 5min infusion at "cup-of-tea" strength.
Chronic treatment with the rooibos HWSS appeared to inhibit lipid accumulation (Fig.
Differentiation of 3T3-L1 cells with 100 [mu]g/ml of the rooibos HWSS decreased the mRNA abundance of PPAR7 (Fig.
Chronic exposure to 100 [mu]g/ml rooibos HWSS reduced the protein levels of PPAR[alpha] (Fig.
The glycerol content in the cell supernatant was decreased by 22% (p [less than or equal to] 0.01) in 3T3-L1 adipocytes differentiated with 100 [mu]g/ml of the rooibos HWSS compared to control cells (Fig.
Basal glucose uptake was improved in the presence of the rooibos HWSS (Fig.
A substantial decrease of 70% (p [less than or equal to] 0.001) was observed in leptin secretion by differentiating 3T3-L1 adipocytes after chronic treatment with rooibos HWSS at a concentration of 100 [mu]g/ml (Fig.