Flavonoids of Aerial Parts of an Endemic Species of the Apiaceae of Algeria, Ammoides atlantica

The genus Ammoides (Apiaceae) tribe of Ammineae includes two species in Algeria, one of which is endemic: Ammoides atlantica (Coss. et Dur.) Wolf; the other one, Ammoides pusilla (Brot.) Breistr, is widespread in the Mediterranean region [1]. The aerial parts of Ammoides atlantica were collected from Megress Mountain (Eastern Algeria) at 1500 m above sea level during June 2004 and identified by Dr. H. Laouer. A voucher specimen (B6308) has been deposited in the Museum d’Histoire Naturelle of Nice (France). The air-dried powdered parts (700 g) of A. atlantica were macerated three times in boiling methanolic solution (70%). The MeOH extract was concentrated to dryness, the residue was dissolved in boiling water (600 mL) after filtration, and the residue was extracted successively three times with AcOEt and n-butanol (3×200 mL) to give 2.5 and 22.7 g of the respective residues. Solvents were evaporated and the residues of n-BuOH and AcOEt extracts were dissolved in small volumes of MeOH. Analysis by two-dimensional paper chromatography using 15% AcOH and BAW (n-BuOH–AcOH–H2O, 4:1:5, upper phase) as solvents indicated that extracts of n-BuOH and AcOEt contain identical separation of flavonoids. The AcOEt extract was applied to a column of silica gel and eluted with a gradient of n-hexane–AcOEt–MeOH with increasing polarity to obtain nine fractions (A-I). Concentration under reduced pressure of fractions B, D, and G gave three precipitates, which were filtered and washed with MeOH to obtain three compounds 1 (10 mg), 2 (32 mg), and 3 (40 mg). Fraction C was purified by preparative TLC on silica gel eluted with n-hexane–AcOEt (2:8) to afford compound 4 (10 mg). Final purification of each compound for spectral analysis was carried out using MeOH over Sephadex LH-20 (Pharmacia Fine Chemicals), prior to UV, MS, and 1H spectral analysis [2, 3]. Hydrolysis of the glycosides 3 and 4 (HCl 0.1 N, 2 h) yielded the sugar residues and the aglycones, all of which were chromatographed with authentic samples. 1H NMR spectra were recorded in CD3OD at 300 MHz. All the structures were in good agreement with literature data. Compound 1, C15H10O5, mp 345°C, identified as apigenin [4]. Compound 2, C15H10O6, mp 330°C, identified as luteolin [5]. Compound 3, C21H20O10, mp 220–222°C identified as apigenin 7-O-glucoside [6]. Compound 4, C21H20O11, mp 239–242°C, identified as luteolin 7-O-glucoside [7]. Only one flavonoid, luteolin 7-O-glucoside [7], has recently been reported from an Egyptian A. pusilla. Compounds 1–4 were isolated for the first time from A. atlantica, and compounds 3, 4 are reported for a second time from a Ammoides species [6, 7]. Compounds 1 and 2 are new for the genus Ammoides.