Biotransformation of flavonoid-7-O-glucuronides by $\beta$-glucuronidases

  • Choi, Ran-Joo (Natural Products Research Institute, College of Pharmacy, Seoul National University) ;
  • Ha, In-Jin (Natural Products Research Institute, College of Pharmacy, Seoul National University) ;
  • Choi, Jae-Sue (Division of Food Science and Biotechnology, Pukyong National University) ;
  • Park, You-Mie (Natural Products Research Institute, College of Pharmacy, Seoul National University) ;
  • Kim, Yeong-Shik (Natural Products Research Institute, College of Pharmacy, Seoul National University)
  • Received : 2009.12.23
  • Accepted : 2010.03.03
  • Published : 2010.03.31

Abstract

$\beta$-Glucuronidases (E.C. 3.2.1.31) from Escherichia coli, Helix pomatia, and bovine liver activity have been investigated on 7-O-glucuronides (baicalin, wogonoside, and luteolin-7-O-glucuronide) and 3-O-glucuronides (quercetin-3-O-glucuronide and kaempferol-3-O-glucuronide). Bovine liver enzyme was not active on any of these substrates. E. coli and H. pomatia enzymes were active on 7-O-glucuronides, however, 3-O-glucuronides were resistant to $\beta$-glucuronidase hydrolysis. These results suggest that glucuronic acid at 7-position is more susceptible to E. coli and H. pomatia $\beta$-glucuronidases than that at 3-position. In addition, the subtle difference of aglycone structure on 7-O-glucuronides affected the preference of enzyme. E. coli enzyme was favorable for the hydrolysis of baicalin, however, H. pomatia enzyme was found to be efficient for the hydrolysis of wogonoside. Both enzymes showed the similar hydrolytic activity towards luteolin-7-O-glucuronide. When the Scutellaria baicalensis crude extract was subjected to enzymatic hydrolysis, baicalin and wogonoside were successfully converted to their aglycone counterparts with H. pomatia at 50 mM sodium bicarbonate buffer pH 4.0. Accordingly, the enzymatic transformation of glycosides may be quite useful in preparing aglycones under mild conditions.

Keywords

References

  1. Chao, J.I., Su, W.C., and Liu, H.F., Baicalein induces cancer cell death and proliferation retardation by the inhibition of CDC2 kinase and surviving associated with opposite role of p38 mitogen-activated protein kinase and AKT. Mol. Cancer Ther. 6, 3039-3048 (2007). https://doi.org/10.1158/1535-7163.MCT-07-0281
  2. Chi, Y.S., Lim, H., Park, H., and Kim, H.P., Effects of wogonin, a plant flavones from Scutellaria radix, on skin inflammation: in vivo regulation of inflammation-associated gene expression. Biochem. Pharmacol. 66, 1271-1278 (2003). https://doi.org/10.1016/S0006-2952(03)00463-5
  3. Gao, Z., Huang, K., Yang, X., and Xu, H., Free radical scavenging and antioxidant activities of flavonoids extracted from the radix of Scutellaria baicalensis Georgi. Biochim. Biophys. Acta 1472, 643-650 (1999). https://doi.org/10.1016/S0304-4165(99)00152-X
  4. Guo, Q., Zhao, L., You, Q., Yang, Y., Gu, H., Song, G., Lu, N., and Xin, J., Anti-hepatitis B virus activity of wogonin in vitro and in vivo. Antivir. Res. 74, 16-24 (2007). https://doi.org/10.1016/j.antiviral.2007.01.002
  5. Jianjun, J., and Huiru, D., Preparation of high-purity baicalein from Scutellaria baicalensis Georgi. Nat. Prod. Res. 22, 1410-1412 (2008). https://doi.org/10.1080/14786410701823967
  6. Jung, H.A., Jung, Y.J., Yoon, N.Y., Jeong, D.M., Bae, H.J., Kim, D.W., Na, D.H., and Choi, J.S., Inhibitory effects of Nelumbo nucifera leaves on rat lens aldose reductase, advanced glycation endproducts formation, and oxidative stress. Food Chem. Toxico. 46, 3818-3826 (2008). https://doi.org/10.1016/j.fct.2008.10.004
  7. Jung, H.A., Kim, J.E., Chung, H.Y., and Choi, J.S., Antioxidant principles of Nelumbo nucifera stamens. Arch. Pharm. Res. 26, 279-285 (2003). https://doi.org/10.1007/BF02976956
  8. Kamata, T., Nishikawa, M., Katagi, M., and Tsuchihashi, H., Optimized glucuronide hydrolysis for the detection of psilocin in human urine samples. J. Chromatogr. B 796, 421-427 (2003). https://doi.org/10.1016/j.jchromb.2003.08.030
  9. Kim, M.J., Kim, N.S., Kim Y.I., Kim, D.K., and Yang, J.H., Improvement of hydrolysis and bioavailability of coprecipitated products of Coptidis rhizome and Scutellaria radix by $\beta$glucuronidase. J. Kor. Pharm. Sci. 33, 91-97 (2003).
  10. Kim, Y.H., Jeong, D.W., Paek, I.B., Ji, H.Y., Kim, Y.C., Sohn, D.H., and Lee, H.S., Liquid chromatography with tandem mass spectrometry for the simultaneous determination of baicalein, baicalin, oroxylin A and wogonin in rat plasma. J. Chromatogr. B 844, 261-267 (2006).
  11. Kimura, Y., and Okuda, H., Effects of flavonoids isolated from Scutellaria Radix on fibrinolytic system induced by trypsin in human umbilical vein endothelial cells. J. Nat. Prod. 60, 598-601 (1997). https://doi.org/10.1021/np970035l
  12. Li-Weber, M., New therapeutic aspects of flavones: The anticancer properties of Scutellaria and its main active constituents wogonin, baicalein and baicalin. Cancer Treat. Rev. 35, 57-68 (2008).
  13. Ohkoshi, E., Nagashima, T., Sato, H., Fujii, Y., Nozawa, K., and Nagai, M., Simple preparation of baicalin from Scutellariae Radix. J. Chromatogr. A 1216, 2192-2194 (2008).
  14. Su, S., He, C.M., Li, L.C., Chen, J.K., and Zhou, T.S., Genetic characterization and phytochemical analysis of wild and cultivated populations of Scutellaria baicalensis. Chem. Biodivers. 5, 1353-1363 (2008). https://doi.org/10.1002/cbdv.200890123
  15. Ikegami, F., Matsunae, K., Hisamitsu, M., Kurihara, T., Yamamoto, T., and Murakoshi, I., Purification and properties of a plant $\beta$-D-glucuronidase from Scutellaria root. Biol. Pharm. Bull. 18, 1531-1534 (1995). https://doi.org/10.1248/bpb.18.1531
  16. Wang, C.Z., Mehendale, S.R., and Yuan, C.S., Commonly used antioxidant botanicals: Active constituents and their potential role in cardiovascular illness. Am. J. Chinese Med. 35, 543-558 (2007). https://doi.org/10.1142/S0192415X07005053
  17. Woo, K.J., Lim, J.H., Suh, S.I., Kwon, Y.K., Shin, S.W., Kim, S.C., Choi, Y.H., Park, J.W., and Kwon, T.K., Differential inhibitory effects of baicalein and baicalin on LPS-induced cyclooxygenase-2 expression through inhibition of C/EBP$\beta$ DNA-binding activity. Immunobiology 211, 359-368 (2006). https://doi.org/10.1016/j.imbio.2006.02.002
  18. Wu, J.A., Attele, A.S., Zhang, L., Yuan, C.S., Anti-HIV activity of medicinal herbs: Usage and potential development. Am. J. Chinese Med. 29, 69-81 (2001). https://doi.org/10.1142/S0192415X01000083
  19. Wu, S., Sun, A., and Liu, R., Separation and purification of baicalin and wogonoside from the Chinese medicinal plant Scutellaria baicalensis Georgi by high-speed counter-current chromatography. J. Chromatogr.A 1066, 243-247 (2005). https://doi.org/10.1016/j.chroma.2005.01.054