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The composition of eight samples of commercial copaiba oils, used in the Amazonian region as antiinflammatory agents and available in popular markets, were analysed by gas chromatography/mass spectrometry (HRGC-MS). Major differences were observed in their chemical composition and some adulterations were pointed out. When tested in vivo oils 1 and 3, and to a lesser extent oil 6, significantly inhibited bradykinin-induced oedema formation. The other tested oils had no effect. When assessed in carrageenan-induced oedema formation, oils 1, 2 and 6, but not oil 3, significantly attenuated the oedema formation. The other tested oils failed to affect carrageenan-induced paw oedema. Oils 1 and 6 were further fractionated and several sesquiterpenes and diterpenes were detected. It is suggested that the naturally occurring sesquiterpenes present in the copaiba oils seem to be responsible for the antiinflammatory action reported in the folk medicine. Furthermore, our results clearly show an adulteration in copaiba oils available in Brazil.

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Two oils exuded from a Copaifera multijuga Hayne tree (Leguminosae-Caesalpinoideae), collected from the same plant, but in different periods of the year, and the hexanic, dichloromethanic and methanolic fractions of one of these oils were analysed by high-resolution gas chromatography (HRGC) and HRGC coupled with mass spectrometry (HRGC-MS). In addition, the in-vivo preliminary anti-oedematogenic actions of the oil and some fractions of it were assessed against carrageenan- and bradykinin-induced oedema formation in the rat paw. Twenty-seven sesquiterpenes and six diterpenes were identified, beta-caryophyllene, alpha-copaene and copalic acid being the main components. The dichloromethanic and methanolic fractions obtained from C. multijuga oil given by the intraperitoneal route caused a significant inhibition of paw oedema caused by carrageenan with inhibition of 49 +/- 13% and 64 +/- 9 %, respectively. Likewise, dexamethasone (the positive control drug) also greatly inhibited carrageenan-induced paw oedema formation (60 +/- 4% at 2 h). The hexanic fraction also significantly inhibited (50 +/- 6%) the paw oedema formation caused by bradykinin. These results suggest the presence of still non-identified active terpene compounds in the oil of C. multijuga that exhibit anti-oedematogenic properties. Of note, the yield of these compounds and the pharmacological actions of the oil, exhibited great seasonal variations, a relevant aspect that should be carefully observed for the correct medicinal use of this plant by the population.

Astilbin (3-0-alpha-1-rhamnosyl-(2R,3R)-dihydroquercetin), the major constituent isolated from Hymeneae martiana and some derivatives obtained by structural modification, such as taxifolin and two related compounds, were evaluated as analgesics by using both writhing test and formalin test in mice. Their anti-oedematogenic actions were also analysed against paw oedema caused by carrageenan, dextran and bradykinin in rat. The results indicated that some compounds, such as taxifolin (2) and its tetramethylated derivative (4) exhibited potent and dose-dependent antinociceptive action against acetic acid-induced abdominal constriction when administered intraperitoneally or orally. They were more potent than acetylsalicylic acid and paracetamol (acetaminophen), two standard drugs used for comparison. Compounds 2 and 4 were also more potent than these drugs in attenuating to the second phase of the formalin-induced licking. Moreover, both compounds showed significant anti-oedematogenic effect, inhibiting the paw oedema formation induced by dextran. In contrast pentaacetylated taxifolin (3) was capable of inhibiting the paw oedema induced by bradykinin.