Preventive effects of polyphenol-rich perilla leaves on oxidative stress and haemolysis

We investigated the effect of perilla leaf extract (PLE) containing polyphenols on various biological functions including antioxidant activity, iron chelation, and red blood cell haemolysis protection. The total phenolic and flavonoid content were determined by colorimetric assay and HPLC analysis. The antioxidant activity was determined by DPPH and ABTS assay. The iron chelating effect was examined by the colorimetric method. Free radical scavenging activity was determined by haemoglobin-induced lipid peroxidation in a linoleic acid model system. Reactive oxygen species (ROS) inhibition was investigated in peripheral blood mononuclear cells. The antihaemolytic activity by AAPH-induced free radicals. The results revealed that PLE contained high levels of total phenolic compounds and total flavonoids (mainly rosmarinic acid). The IC50 values of PLE by DPPH and ABTS radical scavenging assay were 34.3 +/- 3.4 and 9.69 +/- 0.14 mu g/ml, respectively. The iron-binding effect of PLE was exhibited by complex formation with Fe3+-NTA. The iron-chelating activity displayed a moderate IC50 value of 10.1 +/- 0.6 mg/ml. The PLE concentration of 200 mu g/ml, significantly inhibited intracellular ROS 45%. The scavenging activity of PLE in haemoglobin-induced lipid peroxidation resulted in 27% inhibition. PLE also prevented AAPH-induced RBC haemolysis. In conclusion, PLE containing phenolic compounds plays a vital role in free radical scavenging and iron-chelating activities and subsequently prevents lipid peroxidation resulting from RBC haemolysis due to oxidative stress. Perilla products may be developed as health supplements, which could probably be used in prophylaxis and treatment of non-communicable diseases.