Auriculatin 4′-O-Glucoside: A New Prenylated Isoflavone Glycoside fromErythrina eriotricha¹

Abstract

In addition to known compounds, sigmoidin C and 8-(3,3-dimethylallyl)-erythrinin C, also called senegalensin, a new isoflavone glycoside designated auriculatin 4'- O-glucoside was isolated from the chloroform extract of the stem bark of ERYTHRINA ERIOTRICHA. Its structure was elucidated as 7,6-(2''',2'''-dimethyl-2 H-pyrano)-2',5-dihydroxy-8-(3,3-dimethylallyl)-isoflavone 4'- O-beta- D-glucoside on the basis of spectroscopic methods and chemical evidence.

Revised Structures for Senegalensin and Euchrenone b10

“…The assignment of the prenyl group was further confirmed by the NOESY experiment of the dimethyl ether derivative 1a , which showed NOE interactions between a methoxyl group at C-5 (δ 3.86) and the aliphatic protons at C-1‘ ‘‘ (δ 3.37 and 3.40) and between the methoxyl group and an aliphatic proton at C-2‘ ‘‘ (δ 5.21); therefore, compound 1 was determined to be 5,4‘-dihydroxy-6-(3,3-dimethylallyl)-5-hydroxyisopropyldihydrofurano[2,3:7,8]isoflavone . The 1 H NMR spectrum of 1 was in agreement with that of the reported senegalensin, isolated from the stem bark of the Cameroonian medicinal plant, Erythrina senegalensis . , The structure of the reported senegalensin was erroneously shown as 2 through interpretation of its 2D NMR spectroscopic data and its 13 C NMR spectrum. In the 13 C NMR spectrum of the reported senegalensin, the signals of C-6 (δ 103.9) and C-8 (δ 107.7) were incorrectly assigned, and the reverse reassignment signals of C-6 (δ 107.6) and C-8 (δ 102.6) led senegalensin to structure 1 .…”

“…After the excess of trimethylsilyldiazomethane was decomposed with AcOH, the reaction mixture was evaporated to dryness. The resulting residue was purified by column chromatography on Si gel eluting with CHCl3-acetone (10:1) to give 1a (2.3 mg, 50%) as a colorless oil: UV (MeOH) λmax (log ) 202 (4.79), 217 (sh, 4.64), 259 (4.70), 313 (sh, 4.10) nm; IR (KBr) νmax 3440, 1640, 1610 cm -1 ; 1 H NMR (CDCl3) δ 1.25, 1.37 (each 3H, each s, Me-4′′ and -5′′), 1.68, 1.79 (each 3H, each s, Me-4′′′ and -5′′′), 3.28 (1H, dd, J ) 15.4, 8.8 Hz, H-1′′), 3.33 (1H, dd, J ) 15.4, 9.5 Hz, H-1′′), 3.37 (1H, dd, J ) 13.9, 7.3 Hz, H-1′′′), 3.40 (1H, dd, J ) 13.9, 7.3 Hz, H-1′′′), 3.75 (1H, brs, OH), 3.83 (3H, s, OMe-4′), 3.86 (3H, s, OMe-5), 4.82 (1H, dd, J ) 9.5, 8.8 Hz, H-2′′), 5.21 (1H, t, J ) 7.3 Hz, H-2′′′), 6 (8), 391 (13), 373 (10), 361 (8), 331 (11), 323 (7), 178 (43), 59 (7); HREIMS m/z 450.2047 (calcd for C27H30O6, 450.2041).…”

“…5 The 1 H NMR spectrum of 1 was in agreement with that of the reported senegalensin, isolated from the stem bark of the Cameroonian medicinal plant, Erythrina senegalensis. 6,7 The structure of the reported senegalensin was erroneously shown as 2 through interpretation of its 2D NMR spectroscopic data and its 13 C NMR spectrum. In the 13 C NMR spectrum of the reported senegalensin, 8 the signals of C-6 (δ 103.9) and C-8 (δ 107.7) were incorrectly assigned, and the reverse reassignment signals of C-6 (δ 107.6) and C-8 (δ 102.6) led senegalensin to structure 1.…”

The chemistry and biological activities of natural products from Northern African plant families: from Ebenaceae to Solanaceae

“…30 Meanwhile, compounds 32 and 38 were isolated from the Cameroonian species. [42][43][44] Compounds 35 and 36 were evaluated for anticancer activity. The IC 50 values for compound 35 were less 50 mM against 43 cell lines with maximum cytotoxicity against colon cancer cell line HCC2998 (IC 50 ¼ 20 mM), while the IC 50 values were higher than 50 mM in all the ve tested leukemia lines.…”

Erysenegalenseins B and C, Two New Prenylated Isoflavanones from Erythrina senegalensis

“…In recent years, there has been an increase in research efforts on the neutral bioactive compounds of this genus (4,5). As a continuation of an ongoing study on plants of this genus (6)(7)(8), we now report the isolation and structural elucidation of two novel isoflavanones named erysenegalensein B [1] and erysenegalensein C [2], which have been isolated from Erythrina senegalensis DC. Si gel chromatography of the CH2C12 extract of the stem bark of E. senegalensis afforded the novel compounds 1 and 2. Compound 1 was obtained as a yellow oil, [a]20D 0°.…”