Value addition of khus (Vetiveria zizanioides L. Nash) root extracts by elicitor and heat treatment

摘要

Phenolic acids are known to possess many health beneficial effects. Presence of phenolic acids in root extracts of khus (Vetiveria zizanioides L. Nash) established the need to enhance these compounds in khus roots which are used in khus sharbat preparation. Among all the treatments, dual strategy of elicitor (roots treated with chitosan at 200 mg/l for 18 h) followed by heat treatment (100 degrees C for 20 min) showed 5.3, 27.5, 14 and 31.3 folds increase in p-hydroxybenzoic acid, vanillin, p-coumaric acid and ferulic acid, respectively. This treatment also showed the highest antioxidant activities measured in terms of 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging (IC50 66.71 +/- 2.02 mg fresh weight/ml), ferric reducing antioxidant potential (FRAP) value (4670 +/- 4.09 mu M of Fe2+ equivalent/g fresh weight) and 2,2'-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) value (28.11 +/- 0.23 mM/g fresh weight ascorbic acid equivalent) as well as highest total phenolic content (TPC) (10.07 +/- 0.02 mg gallic acid equivalent/g fresh weight. Relative acetylcholinesterase (AChE) inhibitory activity was also found to be highest after chitosan elicitor treatment. Principal component analyses of khus root extracts after elicitor and heat treatment confirmed the major role of vanillin and ferulic acid in the enhancement of antioxidant capacities and AChE inhibitory capacities of khus root extracts. Thus, contributing in the value-addition of khus extracts used in sharbat preparation.