Determination of total tannins in the roots, branches, leaves and pericarps of Juglans mandshurica

Abstract

The roots, barks, branches and pericarps of Juglans mandshurica were used as folk medicine in China and reputed for its treatment of several cancers, such as gastric cancer, liver cancer and leukemia. The extracts of the roots, branches, leaves and pericarps of J. mandshurica have been experimentally proved to show anti-tumor activities. Tannins, which exhibited antioxidant and anti-tumor activities, were the main constituents in J. mandshurica. In this paper, a simple spectrophotometric method was developed for the determination of total tannins in the roots, branches, leaves and pericarps of J. mandshurica collected in Dalian and Anshan of Liaoning Province. Gallic acid was used as standard compound and the content of total tannins was calculated as gallic acid equivalent. As a result of the method validation, a good linearity (r = 0.9997, n = 5) and a high recovery of gallic acid (99.02%, RSD 3.7%, n = 9) was achieved. Eight samples including four parts of J. mandshurica collected in two places were analyzed for their total tannins with the established method. In the corresponding parts of J. mandshurica, except the pericarps, the contents of total tannins showed no significant difference between samples collected in Dalian and Anshan, while the content of total tannins in different parts of J. mandshurica were significantly different. The average content of total tannins in the roots, branches, leaves and pericarps of samples collected in Dalian and Anshan was 45.66, 23.40, 58.24, 3.58 mg g(-1), respectively.