Five New Peltogynoids from Underground Parts of Iris bungei: A Mongolian Medicinal Plant.

Abstract

Iris bungei MAXIM. (family Iridaceae) has been used in Mongolian traditional medicine for the treatment of various diseases, such as bacterial infections, cancer, and inflammation. Some benzoquinones isolated from Iris species have been used as anticancer agents in modern Chinese medicine.2,3) This paper describes the isolation and characterization of five new peltogynoids (1-5) from the underground parts of Iris bungei. Although peltogynoids have been isolated from several genera of the family Leguminosae, [4][5][6][7][8][9][10][11][12] this is the first report of the isolation of peltogynoids from the family Iridaceae and the first X-ray structure determination of peltogynoid-type compounds. Results and DiscussionThe methanolic extract of the underground parts of I. bungei was subjected to repeated column and preparative thin-layer chromatography to obtain compounds 1-5. Irisoid A (1) was isolated as a yellow amorphous powder. The highresolution electron impact mass spectrum (HREI-MS) of 1 showed the [M] ϩ at m/z 328.0597, in agreement with the molecular formula C 17 H 12 O 7 (Calcd 328.0583), indicating 12 degrees of unsaturation. Strong IR absorptions at 1652 (CϭO) and 1628 cm Ϫ1 (CϭC) along with UV bands at 350 (log e 3.93), 278 (log e 4.03), and 203 (log e 4.26) indicated that the compound has a flavone-type skeleton with oxygenation at the C-6a position.13) Typical fragment ions appeared in EI-MS at m/z 313, 182, and 146, indicating the presence of a methoxyl group at C-9 with two hydroxyl groups in ring A, and only one hydroxyl group in ring B (Fig. 1).The 1 H-NMR spectrum (C 5 D 5 N, 400 MHz) of 1 showed two sets of signals for a total of four aromatic protons, along with signals for one O-methylene and one methoxyl group (Table 1). This revealed the presence of two independent aromatic spin systems in the molecule. A singlet at d 6.98 corresponded to the H-11 of ring A. Three signals at d 7.19 (br d, J 2,3 ϭ8.3 Hz), 7.29 (dd, J 3,2 ϭ8.3 Hz and J 3,4 ϭ7.3 Hz) and 6.70 (br d, J 4,3 ϭ7.3 Hz) were assigned to the aromatic H-2, H-3, and H-4 protons, respectively. This assignment indicated the presence of substituents at C-1 and C-4a of the aromatic ring B. Two downfield methylene protons resonated as a singlet at d 5.13 (H-5), indicating the presence of an ethereal oxygen and aromatic moiety vicinal to the methylene carbon. A methoxyl methyl appeared as a singlet at d 3.93 substituted at C-9 of ring A. The appearance of a downfield singlet at d 12.82 when the 1 H-NMR was recorded in dimethyl sulfoxide (DMSO)-d 6 confirmed the presence of the OH group at C-8, which is involved in the hydrogen bonding with carbonyl group at C-7.The broad-band (BB) decoupled 13 C-NMR spectrum of 1 showed resonances for all 17 carbons in the molecule (Table 1). The audited distortionless enhancement by polarization transfer (ADEPT) spectrum revealed the presence of one methyl, one methylene, four methines, and 11 quaternary carbons. The carbonyl carbons appeared in the most downfielded region at d 175.4, whereas the other im...

Two New Peltogynoids fromAcacia niloticaDelile with Kinase Inhibitory Activity

“…A strong bathochromic shift induced by the addition of aluminum trichloride revealed the presence of a free hydroxy at C-8, implied by a hydrogen bond with the neighboring carbonyl group at C-7. The 1 H-NMR spectrum displayed signals associated with a peltogynoid oxygenated at positions 2, 3, 8, and 10, i.e., (i) two metacoupled doublets at δ = 6.37 and 6.51, typical for H-9 and H-11, respectively; (ii) two aromatic singlets at δ = 6.70 and 7.26 attributed to H-4 and H-1, the latter deshielded by the peri effect of the polyaromatic system; and (iii) a typical O-methylene singlet at δ = 5.25 [14][15][16][17][18]. Additional signals included three methoxy singlets at δ = 3.90, 3.96, and 4.02 and a downfield singlet at δ = 12.65, exchangeable by addition of D 2 O, which confirmed the presence of the OH group at C-8 involved in the hydrogen bonding with the carbonyl group at C-7.…”

“…These data permitted depiction of the structure of acanilol A as 8-hydroxy-2,3,10-trimethoxy- [1]benzopyrano [3,2-c][2]-benzopyran-7(5H)-one (1), in good agreement with the 13 C-NMR spectrum, which revealed the presence of a carbonyl singlet, sp 2 carbons (10 quaternary C, four CH), and four sp 3 carbons (one CH 2 and three CH 3 ). Of particular interest was the characteristic signal of the peltogynoid methylene carbon C-5 at δ = 68.2 [18]. All 13 C-NMR peaks were assigned on the basis of HMQC and HMBC experiments.…”

Flavonoids fromIris songaricaand their Antioxidant and Estrogenic Activity

“…Finally, from above evidence and comparison with 5,2′,3′-trihydroxy-6,7-methylenedioxyflavanone [7], songaricol (1) was elucidated as (2R,3R)-5,2′,3′-trihydroxy-6,7-methylenedioxyflavonol. Known compounds were elucidated as ayamenin A (2) [8], irisflavone A (3) [9], 5,7-dihydroxy-2′,6-dimethoxyisoflavone (4) [10], irilin B (5) [9], 5,3′-dihydroxy-7,8,2′-trimethoxyisoflavone (6) [11] and irisoid A (7) [12] by comparing their spectroscopic data with those reported previously. Compounds 2 -7 were isolated for the first time from I. songarica.…”

Secondary metabolites of the choosen genus iris species

“…Five peltogynoids, irisoids, have been isolated from the underground parts of Iris bungei. The structures of the new compounds were established on the basis of spectroscopic methods (CHOUDHARY et al, 2001). A novel dimeric 1,4-benzoquinone and resorcinol derivative, Belamcandaquinone N, and two known compounds, 3-hydroxyirisquinone and 5-[(Z)-10heptadecenyl] resorcinol, were isolated from the seeds of Iris bungei.…”