Abstract
Diabetic patients develop ischemic heart disease and strokes more readily. Following
an ischemic event, restoration of blood flow increases oxidative stress resulting
in myocardial damage, termed ischemia/reperfusion injury. Aspalathus linearis (rooibos),
rich in the antioxidant phenolic compound aspalathin, has been implicated as cardioprotective
against ischemia/reperfusion injury with undefined mechanism in control rats. Primarily,
the therapeutic potential of Afriplex green rooibos extract to prevent ischemia/reperfusion
injury in cardiovascular disease-compromised rats was investigated. Additionally,
Afriplex Green rooibos extractʼs cardioprotective signaling on metabolic markers and
stress markers was determined using western blotting. Three hundred male Wistar rats
received either 16-wk standard diet or high-caloric diet. During the final 6 wk, half
received 60 mg/kg/day Afriplex green rooibos extract, containing 12.48% aspalathin.
High-caloric diet increased body
weight, body fat, fasting serum triglycerides, and homeostatic model assessment
of insulin resistance – indicative of prediabetes. High-caloric diet rats had increased
heart mass, infarct size, and decreased heart function. Afriplex green rooibos extract
treatment for 6 wk lowered pre-ischemic heart rate, reduced infarct size, and improved
heart function pre- and post-ischemia, without significantly affecting biometric parameters.
Stabilized high-caloric diet hearts had decreased insulin independence via adenosine
monophosphate activated kinase and increased inflammation (p38 mitogen-activated protein
kinase), whereas Afriplex green rooibos extract treatment decreased insulin dependence
(protein kinase B) and conferred anti-inflammatory effect. After 20 min ischemia,
high-caloric diet hearts had upregulated ataxia–telangiectasia mutated kinase decreased
insulin independence, and downregulated insulin dependence and glycogen synthase kinase
3 β inhibition. In
contrast, Afriplex green rooibos extract supplementation downregulated insulin
independence and inhibited extracellular signal-regulated kinase 1 and 2. During reperfusion,
all protective signaling was decreased in high-caloric diet, while Afriplex green
rooibos extract supplementation reduced oxidative stress (c-Jun N-terminal kinases
1 and 2) and inflammation. Taken together, Afriplex green rooibos extract supplementation
for 6 wk preconditioned cardiovascular disease-compromised rat hearts against ischemia/reperfusion
injury by lowering inflammation, oxidative stress, and heart rate.
Key words
Aspalathus linearis - Leguminosae - rooibos - aspalathin - reperfusion injury - ischemia
- diabetes - cardiovascular disease
