PARTE UTILIZADA= Used part: Hoja. 

ACCIÓN FARMACOLÓGICA= Pharmacological action: Béquico, antiperiódico. 

COMPOSICIÓN QUÍMICA= Chemical composition: The fractions 15–22 yielded two triterpenes, lupeol (15, 147.9 mg, MP 163–165_C) and lupeol acetate (16, 1.32 g, MP 143–145_C); fractions 36–39 yielded sitosterol and stigmasterol mixture (10 and 11, 47.5 mg), and from fractions 59–65 spinasterol was obtained (9, 31.2 mg, MP 148–149_C). The ethyl acetate extract afforded a precipitate containing the mixture of 3-O-b-D-glucopyranosylspinasterol and 3-O-b-D-glucopyranosyl-stigmasterol (12 and 14, 28.4 mg). The solution of ethyl acetate extract was concentrated under vacuum to yield a residue (11.09 g) that was chromatographed on a silica gel column using CHCl3: MeOH to MeOH (100%). The collected fractions were analyzed by TLC plate and successively filtered on a Sephadex LH-20 column using methanol as mobile phase. The first fractions yielded one flavonoid, 30,40,5-trihydroxy- 6,7-dimethoxyflavone (2, 3.8 mg), and a mixture of three 2-hydroxy-cinnamic acid derivatives (3 + 4 + 5, 12.2 mg), besides one diterpene ester, 9,15-dihydroxykauren-19-O-b- D-glucopyranosyl-19-oate (1, 8.9 mg, MP 218–220_C). The methanolic extract was submitted to column chromatography of reverse-phase C18 using MeOH:H2O. The fractions 18–22 yielded the 2-O-glucopyranosyl-cinnamic acids derivates (6, 7 and 8, 27.6 mg). The dry flowers (220.0 g) were submitted to maceration at room temperature with hexane and MeOH. The hexane extract (9.75 g) was chromatographed on silica gel with CH2Cl2:AcOEt:MeOH mixture to methanol 100%. The fractions 10–15 afforded the two triterpenes taraxasterol (17, 147.1 mg, MP 149–153_C) and taraxasterol acetate (18, 147.1 mg, MP 152–155_C); the fractions 42–27 yielded one precipitate in which were identified three steroids, the mixture of 3-O-b-D-glucopyranosyl-sitosterol and 3-Ob- D-glucopyranosyl-stigmasterol (13 and 14, 25.4 mg). The purification of fractions 27–32 afforded 3-O-b-D-glucopyranosyl- spinasterol (12, 44.3 mg, MP 144–147_C). The MeOH extract (15.2 g) was fractionated on a sephadex LH- 20 column using CHCl3:MeOH (1:1). The fractions were analyzed by [1] H and 13C NMR besides GC/MS, which allowed the identification of three triterpenes, lupeol + aand b-amyrin (15 + 19 + 20, 31.3 mg). Their chemical structures were identified by IR [1], H and 13C NMR (HBBD and APT, 100 MHz) data analysis of the fractions containing the triterpenes 15–20, according to the methodology used by Olea and Roque [2], besides comparison with spectra of the compounds isolated from Parahancornia amapa [3] and the data described in the literature [4]. The same analyses were done for 9–14 including comparison with the literature data [5]. To define the structures of compounds 1–8, detailed analysis of 2D NMR (1H-1H-COSY and NOESY, HMQC, HMBC) spectra was used as well as comparison with literature data of 1 [6] (including [a]D = –87 (MeOH), isolated from Ageratina vacciniaefolia, 2 [7, 8], 3–8 [9, 10], isolated from Prunus cornuta and Polypodium decomanum. This is the first report on the isolation of these compounds in E. macrocephalum. 

ZONA GEOGRÁFICA= Geografical zone: Argentina.

1) TOURSARKISSIAN, Martín. Plantas medicinales de Argentina : sus nombres botánicos, vulgares, usos y distribución geográfica. Buenos Aires : Hemisferio Sur, 1980, p.31.

2) VEGA, Maria R. G., et al. Chemical constituents from the Paraguayan medicinal plant, Eupatorium macrocephalum Less. Journal of Natural Medicines. 2008, vol.62, nº1, p.122-123.