Cornusiin A, a dimeric ellagitannin forming four tautomers, and accompanying new tannins in Cornus officinalis.

A LC/QTOF–MS/MS Application to Investigate Chemical Compositions in a Fraction with Protein Tyrosine Phosphatase 1B Inhibitory Activity from Rosa Rugosa Flowers

“…Peaks 20 and 25 gave a [M À H] À ion at m/z 935.07 (C 41 H 28 O 26 ) and the fragment ions, such as 483, 300.99, 169 and 125, etc., were similar to the fragment ions of di-O-galloyl-HHDP-glucose, indicating that they are ellagitannins. It is worthy noting that the abundant ion at 450.9916 with the molecular formula of C 21 H 8 O 12 was observed in their MS 2 spectra, which suggests the presence of a flavogallol group (Okuda et al, 1984;Barakat et al, 1997). It was identified as di-O-galloyl-lactonised valoneoyl-glucose.…”

Systematics and health effects of chemically distinct tannins in medicinal plants

“…The oligomers have been found to be widely distributed in medicinal plants. They posses a variety of structures, examples being gemins A, B and C (dimers) from Geum japonicum, an anti-inflammatory agent and a diuretic (Yoshida et al, 1982b,d, Fig 1985a), rugosins D, E and F (dimers) from Rosa rugosa, an antidiarrheic medicinal plant (Hatano et al, 1990c), cornusiins A (dimer), C (trimer), D, E (dimers) and F (trimer) from Cornus officinalis (Okuda et al, 1984d;Hatano et al, 1989a, and malabatrins B, C and D from Melastoma malabathricum . Several tetramers, e.g., trapanin B (22) from Trapa japonica, a tonic (Hatano et al, 1990a), nobotanin K from melastomataceous plants , and hirtellin Q 1 (along with a trimer, hirtellin T 1 and a dimer, hirtellin G) from Reaumuria hirtella (Ahmed et al, 1994b), as well as a pentamer from Monochaetum multiflorum (Jose et al, 2001) were also identified.…”

Tannins of hamamelidaceous plants. III. Isorugosins A, B and D, new ellagitannins from Liquidambar formosana.

“…The 114-NM R spectrum (500 MHz, in acetone-d6) of 10 indicates the presence of three galloyl groups [6 7.11 (2H, s), 6.99 (2H, s) and 6.90 (2H, s)], a valoneoyl group [6 7.28 (1 H, s, HA), 6.65 (1 H, s, HO and 6.29 (1 H, s, HB)] and a fl-glucopyranose core adopting the 4C , conformation [6 6.17 Rugosins A (6), B (7) and D (18) have not been found in the fractions obtained from L. formosana. It is biogenetically significant that the isomers of isorugosins A (10), B (1) and D (11) concerning the orientation of the valoneoyl group at 0-4 and 0-6 of the glucose cores, are absent in L. formosana, and that the latter type of tannins, 10, 1 and 11, have not been found in Rosa rugosa or in Coriaria japonica, which contain the former type of tannins, 6, 7 and 18 8,10.13,14) As tellimagrandin I (14) and tellimagrandin 11(17), which are presumed to be precursors of both types of tannins described above, are present in all of the three plants,2, l 0,14) it is very probable that the C-0 oxidative coupling' S) between the galloyl part and the HHDP part of the valoneoyl group in the biogenesis of isorugosins A, B and D (in L. …”