PROTECTION OF BIOMOLECULES AGAINST IN VITRO OXIDATIVE DAMAGE BY THE ANTIOXIDANTS FROM METHANOLIC EXTRACT OF TRIGONELLA FOENUM-GRAECUM SEEDS

Fenugreek (Trigonella foenum-graecum) seeds were extracted in 80% methanol to examine the content of various potent antioxidant compounds and their influence on in-vitro oxidation of biomolecules i.e. amount. proteins, lipids and DNA. Fenugreek extract had polyphenols (9.47 +/- 0.10 mg GAE/g dry seeds) as major antioxidant principle. Gallic acid (170.335 mu g), caffeic acid (164.550 mu g), ellagic acid (184.879 mu g) and quercetin (215.814 mu g)/g dry weight fenugreek seeds were identified in methanolic extract by HPLC analysis. Other antioxidant compounds ascorbate, tocopherol and riboflavin were present in very low amounts. Antioxidant properties were assayed using DPPH free radical scavenging activity. Fenugreek extract inhibited the metal induced oxidation of proteins and lipids. Presence of the extract could protect DNA against H2O2-induced oxidative stress. IC50 value of fenugreek seeds was estimated by these mechanisms. The results of this study indicate that polyphenol rich methanolic extract of fenugreek had efficient free radical scavenging, reducing and metal chelating activity to protect biomolecules like proteins, lipids and DNA against oxidative stress.