Planta Med. 57(1991) 83
Letters
spectrum (MeOH) Amax nm (loge) 398 (3.71), 332 (3.85), 300
(4.23), 272(4.60), 249(4.44), 226(4.14), 213(4.16), 264 sh (4.51) closely resembles that of gravacridondiol (3) (8). In the MS the molecular ion appears at m/z = 383 (100%), further ions are at in/z = 341 (9%), 323 (46 %), 310 (17 %), 292(88%), 266 (97%), 43 (75%). The loss of 42 and 60
amu, respectively, and the intense peak at m/z =
43
with an IR band at 1737 cm' — that 1 is a gravacridondiolacetate. The position of the acetyl suggested — together
group followed from comparison of the 1H- and 13C-NMR data of 1 and 3 (Tables 1 and 2). Table 2
13C-NMR shi fts of 1° and 3b
1
3
121.19 142.63 99.88 166.81 72.52 68.39
120.0
91.5 164.9 179.9 125.2 121.4
C-14 C-15 C-16 C-17 C-18 C-19 C-20
134.1
N-CE-I3
115.7
Ac-CH3 Ac-CO
32.43 20.23c 170.97
3
1 C-i
3810
37.7
C-2
86.21 92.57 166.10 180.98 126.38 121.66 133.98 114.66 143.41 106.34
86.3
C-4 C-S
C-6 C-7
C-s C-9
C-lO C-12
C-l3
143.1
20.9U
142.1
101.4 167.4 72.7 65.9 20.6 31.4 —
105.0
Measured at 100.40 MHz in CDCI3. Values taken from Ref. (5).
Values may be interchanged.
Inhibitory Effects of Galloylated Flavonoids on Xanthine Oxidase Tsutomu Hatano', Taeko Yasuhara1, Rieko Yoshihara, Yukihiko Ikegai-ni', Muneto Matsuda', Kazufumi Yazaki1, Isao Agata2. Sansei Nishi be2, Tadataka Noro3, Masao Yoshizaki4, and Takuo Okuda'-5 1
2
Faculty of Pharmaceutical Sciences, Okayama University, Tsushima,
Okayama 700, Japan Faculty of Pharmaceutical Sciences, Higashi Nippon Gakuen University, Ishikari-tobetsu, Hokkaido 061-02, Japan School of Pharmaceutical Sciences. University of Shizuoka, Yada, Shizuoka 422, Japan Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Sugitani, Toyama 930-01, Japan Address for correspondence
Received: August 8, 1989
Xanthine oxidase (XOD) causes gout and is also responsible for oxidative damage to living tissues (1, 2).
Various types of phenolics including tannins (2, 3) have
been reported to inhibit this enzyme. We have now examined the effects of several galloylated flavonoids on XOD, since galloylated flavonoids have been found to show some activities similar to those of tannins (4, 5). All of the galloylated flavonoids tested in the present experiment, ex-
cept for hyperin-2"-gallate (1) (from Pyrola incarnata The observed downfield shift of the signal of C-19 in the 33C-NMR (Table 2) and of the doublets of H-19a and H-19b in the 1H-NMR (Table 1) clearly indicate that the acetyloxy group is bond to C-19.
Acknowledgements This work was financially supported by the BMJFFG of the F.R.G.
References 2
Groger, D. (1988) Pharmazie 43, 815. Paulini, H., Schimmer, 0. (1989) Mutagenesis 4, 45.
Paulini, H., Popp, R., Schimmer, 0., Ratka, 0., Rdder, E. (1991) Planta Med. 57, 59—61.
Reisch, 1., Rôzsa, Zs., Szendrei, K., Novak, I., Minker, E. (1976)
6
8
Phytochemistry 15, 240. Bergenthal, D., Mester, 1., Rózsa, Zs., Reisch, J. (1979) Phytochemistry 18, 161. Rôzsa, Zs., Szendrei, K., Kovacs, Z., Novak, I., Minker, E., Reisch, J. (1978) Phytochemistry 17, 169. Nahrstedt, A., Eilert, U., Wolters, B., Wray, V. (1981) Z. Naturforsch. 36 c, 200. Reisch,
J., Rôzsa, Zs., Szendrei, K., Novak, I., Minker, E. (1972)
Phytochemistry 11,2121. Nahrstedt, A., Wray, V., Engel, B., Reinhard, E. (1985) Planta Med. 517.
Fisch.) (4), have been isolated from the following new plant sources whose medicinal usages are given in references (6— 8): astragalin-2"-gallate (2) and isoquercitrin-2"-gallate (3) from Euphorbia maculata L., astragalin-6"-gallate (4) from Rhus sylvestris Sieb. et Zucc., and quercitrin-2"-gallate (5) from Koelreuteria paniculata Laxmann.
The results are summarized in Table 1. These galloylated flavonoids showed inhibitory effects with IC50 values 1.9—3.6 x iO M, in spite of a report that the inhibitory activity of 3 was very weak (9). The inhibitory ef-
fects of 1—5 observed in the present study are markedly stronger than the inhibitory effects of the corresponding flavonol glycosides lacking a galloyl group (1 > hyperin; 2, 4> astragalin; 3 > isoquercitrin; 5 > quercitrin). It is observed that the differences in the constituent sugars among the galloylated flavonoids noticeably affect their inhibitory activity (1
Letters
spectrum (MeOH) Amax nm (loge) 398 (3.71), 332 (3.85), 300
(4.23), 272(4.60), 249(4.44), 226(4.14), 213(4.16), 264 sh (4.51) closely resembles that of gravacridondiol (3) (8). In the MS the molecular ion appears at m/z = 383 (100%), further ions are at in/z = 341 (9%), 323 (46 %), 310 (17 %), 292(88%), 266 (97%), 43 (75%). The loss of 42 and 60
amu, respectively, and the intense peak at m/z =
43
with an IR band at 1737 cm' — that 1 is a gravacridondiolacetate. The position of the acetyl suggested — together
group followed from comparison of the 1H- and 13C-NMR data of 1 and 3 (Tables 1 and 2). Table 2
13C-NMR shi fts of 1° and 3b
1
3
121.19 142.63 99.88 166.81 72.52 68.39
120.0
91.5 164.9 179.9 125.2 121.4
C-14 C-15 C-16 C-17 C-18 C-19 C-20
134.1
N-CE-I3
115.7
Ac-CH3 Ac-CO
32.43 20.23c 170.97
3
1 C-i
3810
37.7
C-2
86.21 92.57 166.10 180.98 126.38 121.66 133.98 114.66 143.41 106.34
86.3
C-4 C-S
C-6 C-7
C-s C-9
C-lO C-12
C-l3
143.1
20.9U
142.1
101.4 167.4 72.7 65.9 20.6 31.4 —
105.0
Measured at 100.40 MHz in CDCI3. Values taken from Ref. (5).
Values may be interchanged.
Inhibitory Effects of Galloylated Flavonoids on Xanthine Oxidase Tsutomu Hatano', Taeko Yasuhara1, Rieko Yoshihara, Yukihiko Ikegai-ni', Muneto Matsuda', Kazufumi Yazaki1, Isao Agata2. Sansei Nishi be2, Tadataka Noro3, Masao Yoshizaki4, and Takuo Okuda'-5 1
2
Faculty of Pharmaceutical Sciences, Okayama University, Tsushima,
Okayama 700, Japan Faculty of Pharmaceutical Sciences, Higashi Nippon Gakuen University, Ishikari-tobetsu, Hokkaido 061-02, Japan School of Pharmaceutical Sciences. University of Shizuoka, Yada, Shizuoka 422, Japan Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Sugitani, Toyama 930-01, Japan Address for correspondence
Received: August 8, 1989
Xanthine oxidase (XOD) causes gout and is also responsible for oxidative damage to living tissues (1, 2).
Various types of phenolics including tannins (2, 3) have
been reported to inhibit this enzyme. We have now examined the effects of several galloylated flavonoids on XOD, since galloylated flavonoids have been found to show some activities similar to those of tannins (4, 5). All of the galloylated flavonoids tested in the present experiment, ex-
cept for hyperin-2"-gallate (1) (from Pyrola incarnata The observed downfield shift of the signal of C-19 in the 33C-NMR (Table 2) and of the doublets of H-19a and H-19b in the 1H-NMR (Table 1) clearly indicate that the acetyloxy group is bond to C-19.
Acknowledgements This work was financially supported by the BMJFFG of the F.R.G.
References 2
Groger, D. (1988) Pharmazie 43, 815. Paulini, H., Schimmer, 0. (1989) Mutagenesis 4, 45.
Paulini, H., Popp, R., Schimmer, 0., Ratka, 0., Rdder, E. (1991) Planta Med. 57, 59—61.
Reisch, 1., Rôzsa, Zs., Szendrei, K., Novak, I., Minker, E. (1976)
6
8
Phytochemistry 15, 240. Bergenthal, D., Mester, 1., Rózsa, Zs., Reisch, J. (1979) Phytochemistry 18, 161. Rôzsa, Zs., Szendrei, K., Kovacs, Z., Novak, I., Minker, E., Reisch, J. (1978) Phytochemistry 17, 169. Nahrstedt, A., Eilert, U., Wolters, B., Wray, V. (1981) Z. Naturforsch. 36 c, 200. Reisch,
J., Rôzsa, Zs., Szendrei, K., Novak, I., Minker, E. (1972)
Phytochemistry 11,2121. Nahrstedt, A., Wray, V., Engel, B., Reinhard, E. (1985) Planta Med. 517.
Fisch.) (4), have been isolated from the following new plant sources whose medicinal usages are given in references (6— 8): astragalin-2"-gallate (2) and isoquercitrin-2"-gallate (3) from Euphorbia maculata L., astragalin-6"-gallate (4) from Rhus sylvestris Sieb. et Zucc., and quercitrin-2"-gallate (5) from Koelreuteria paniculata Laxmann.
The results are summarized in Table 1. These galloylated flavonoids showed inhibitory effects with IC50 values 1.9—3.6 x iO M, in spite of a report that the inhibitory activity of 3 was very weak (9). The inhibitory ef-
fects of 1—5 observed in the present study are markedly stronger than the inhibitory effects of the corresponding flavonol glycosides lacking a galloyl group (1 > hyperin; 2, 4> astragalin; 3 > isoquercitrin; 5 > quercitrin). It is observed that the differences in the constituent sugars among the galloylated flavonoids noticeably affect their inhibitory activity (1
