Abstract

*Dharuman Joghee, *Angayarkanni Raja, 1Sivamoorthi S, Harishkumar A, Jeevanandham S, Bency Baby

ABSTRACT

Sweet potato is an edible tuber reported to be rich in antioxidants and other nutrients. Results of the previous studies have presumed that it is a rich source of caffeic acid which is an important antioxidant of medicinal values. Hence, a simple, precise and rapid HPLC method was developed for the estimation of caffeic acid and applied to the analysis of sweet potato extract. For the separation a Phenomenex C18 column was used as a stationary phase, 0.2% ortho-phosphoric acid in water and acetonitrile in a ratio of (81:19) was used as a mobile phase. The flow rate has been maintained at 1.2 ml/min and detection was carried at a wavelength of 325 nm. Good separation of caffeic acid was obtained with a retention time of 6.5 mins. The calibration curve showed good linearity (r2= 0.997) in the concentration range of 1.6 ?g/ml to 25.6?g/ml. The relative standard deviation of intra-day and inter-day precision for caffeic acid was found to be less than 3% for caffeic acid. The limit of detection was found to be 28.00 ng/ml and the limit of quantitation was found to be 77.00 ng/ml. The content of caffeic acid, was quantified in methanolic extracts of different parts of sweet potato using the newly developed HPLC method. Among the samples sweet potato peel extract has been shown to contain 0.1415±0.015 mg of caffeic acid and sweet potato leaf was shown to contain 0.00108±0.0022 mg/100mg of the extract respectively, while the rhizome extract has shown no appreciable response to the detector system. Thus, the present research suggests that sweet potato peel which is generally removed off before its consumption has rich caffeic acid content than the other parts of the tuber and may be consumed along with the peel which has no detrimental effects on its taste and culinary values.