The crystal and molecular structure of helichrysoside, a new acylated flavonoid glycoside from helichrysum kraussii

✍ Scribed by H.A. Candy; M. Laing; C.M. Weeks; G.J. Kruger

• Publisher: Elsevier Science
• Year: 1975
• Tongue: French
• Weight: 188 KB
• Volume: 16
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)72097-1

✦ Synopsis

Helichrysum kraussii Sch. Bip. is a compact, herbaceous shrub' which grows in profusion in the sandy soil along the coastal belt of Natal. Because little is known of the chemical taxonomy of this plant, a detailed investigation was undertaken2. The golden yellow flower heads were milled and extracted, in turn, with hexane, ether, acetone and methanol. From the hexane extract 3,5-dihydroxy-6,7,8-trimethoxyflavone was isolated. In addition to L(-)-2-0-methylinositol and 3-0-methylquercetin the acetone extract yielded a new acylated flavonoid glucoside, helichrysoside. This was scluble in acetone, methanol and ethanol but could not be satisfactorily crystallised from any of these anhydrous solvents. Ready crystallisation was accomplished, however, by adding water dropwise to a solution of the solid in either boiling acetone or methanol. Un cooling, small bright yellow hexagonal plates were obtained; m.p. 181-184', [a]: -44'(MeOH); h,,(MeOH) 223sh, 260sh, 265, 302sh, 312, 353sh nm; X,,(MeOH-NaOMe) 271, 312sh, 365, 405sh nm; ~~~~(Me0H-AlC13) 226sh, 276, 308, 440 nm. (Loss on drying in vacua over P205 at room temp. for 16 hr 11.1%; found C = 56.5, H = 4.6%; talc. for CI,,Hz601,, 1.5 H,O; C = 56.50; H = 4.55%; talc. for loss of 4.5 Hz0 10.7%). The dehydrated material melted between 260-270' with decomposition.

The crystals (from acetone and water) were orthorhonbic, space group P212~2; a = 7.51,