Air-dried and powdered aerial parts of A. campestris L. subsp. campestris, including inflorescences (252 g), were successively extracted in a Soxhlet apparatus (72 h) with cyclohexane (3 L), CH2Cl2 (3 L), EtOAc (3 L) and MeOH (3 L). Solvents were then evaporated under reduced pressure to yield 12.9 g of cyclohexane-soluble extract, 9.0 g of dichloromethane-soluble extract, 3.9 g of ethylacetate-soluble extract and 22.8 g of methanol-soluble extract. The whole cyclohexane-soluble extract was subjected to a medium pressure liquid chromatography (MPLC) over Si gel using 100% cyclohexane to cyclohexane/EtOAc (75/25, v/v) in 5% stepwise elution to yield 99 100 ml fractions. Fractions 45e49 (0.71 g) were combined and purified by preparative TLC using CH2Cl2/EtOAc (95/5, v/v) as eluent to yield 3.4 mg (0.023%) of 4,20 -dihydroxy-40 -methoxychalcone 1 (Ramakrishnan et al., 1974) and 3.6 mg (0.028%) of 20 ,50 -dihydroxy-4-methoxychalcone 2 (Tiwari and Singh, 1978). Fractions 62e65 (0.7 g), eluted with cyclohexane/EtOAc (85/15, v/v) were purified by preparative TLC using CH2Cl2/MeOH (97/3, v/v) as eluent to yield 4.2 mg (0.033%) of 5,7-dihydroxy-3,40 -dimethoxyflavone 3 (Grouiller and Pacheco, 1967). Fraction 89 (0.25 g) eluted with the same mixture was also purified by preparative TLC [CH2Cl2/EtOAc (97/3, v/v)] to yield 3.2 mg (0.023%) of 5,7-dihydroxy-3,40 ,50 -trimethoxyflavone or 3,30 ,40 trimethoxyquercetin 4 (Stevens et al., 1999). Dichloromethane-soluble extract (9.0 g) was subjected to MPLC using CH2Cl2 (100%) to CH2Cl2/EtOAc (70/30, v/ v) in 5% stepwise elution to yield 87 100 ml fractions. Fractions 64e69 (0.57 g), eluted with CH2Cl2/EtOAc (90/10, v/v), were purified by preparative TLC [CH2Cl2/EtOAc (60/40, v/v)] to give 3.4 mg (0.038%) of 3,5,7,40 -tetrahydroxy-30 -methoxyflavone or isorhamnetin 5 (Shang et al., 2006). Fractions 75e79 (0.094 g) [CH2Cl2/EtOAc (85/15, v/v)] were subjected to preparative TLC [CH2Cl2/EtOAc (50/50, v/v)] to give 3.1 mg (0.03%) of 4,20 ,40 -trihydroxychalcone or isoliquiritigenin 6 (Markham and Ternai, 1976). EtOAc soluble extract (3.9 g) was subjected to MPLC using cyclohexane/EtOAc (95/5, v/v) to cyclohexane/EtOAc (55/45, v/v) in 5% stepwise elution (26 100 ml fractions) and then using CH2Cl2/MeOH (98/2e70/30, v/v) in 4% stepwise elution (42 100 ml fractions). Fractions 1e10 (0.43 g) were combined and purified by preparative TLC using CH2Cl2/cyclohexane (75/25, v/v) to yield three isocoumarins, namely (þ)-(S,R)-epoxyartemidin 7 [6.1 mg, 0.16%], E-artemedin 8 [5.3 mg, 0.13%] (Engelmeier et al., 2004), and 3-formylisocoumarin or artemidinal 9 [3.9 mg, 0.10%] (Mallabaev et al., 1971). Known compounds were identified through MS, 1D and 2D-NMR spectroscopy and by comparison with their literature data. (þ)-(S,R)-epoxyartemidin 7 was unambiguously identified as the enantiomer of (-)-(R,S)-epoxyartemidin, recently isolated from Artemisia dracunculus (Engelmeier et al., 2004), the absolute configuration of which has been determined following the kinetic resolution method of Horeau (Lutz-Kutschera et al., 2003). The occurrence of simple flavonols, such as methylether derivatives of quercetin and kaempferol, in this Algerian subspecies is in accordance with previous observations (Ivancheva and Tsvetkova, 2003; Valant-Vetschera et al., 2003) even though exudate results may not be fully comparable with results from chopped material. However, there was previously only one report on the isolation of chalcones from the genus Artemisia since butein and isoliquiritigenin were found in Artemisia laciniata (Chemesova et al., 1990). It may be noticed that to date the quite unusual 20 ,50 -dihydroxy-4-methoxychalcone has only been described in Cassia javanica (Fabaceae) (Tiwari and Singh, 1978). It is also very interesting to note that though isocoumarins are already described in the species of Artemisia (Riggins and Clausen, 2003), the co-occurrence of artemidin, epoxyartemidin and artemidinal was only previously reported for the spice tarragon, A. dracunculus (Mallabaev et al., 1971; Engelmeier et al., 2004). The latter observation is thus in very good agreement with the infragenic classification established by De Candolle (1837), A. campestris and A. dracunculus belonging to the same section Dracunculus Besser.