Pterodon emarginatus : Antinociceptive Synergistic Effect of Geranylgeraniol and Vouacapans Fractions

Synergy considers that a plant extract or combination of compounds together is more beneficial than an isolated compound. Pterodon emarginatus Vogel, Fabaceae, fruits are popularly used due to their anti-inflammatory activities, which have relationship with diterpenes furans (vouacapans) and geranylgeraniol. This study evaluated the pharmacological interactions of a sesquiterpenes (α-humulene and trans -caryophyllene, fraction A) enriched fraction, a geranylgeraniol (fraction B), and a vouacapans enriched fraction (fraction C) obtained from the dichloromethane extract, tested on an antinociceptive model. First, all individual fractions had their median effective dose (ED 50 ) determined in abdominal writhing test induced by acetic acid. Fractions A and B gave ED 50 values of 102.34 and 101.96 mg/kg, respectively, whereas fraction C provided the lowest ED 50 value of 63.83 mg/kg. When fractions A and C (3:1) were associated, both at their ED 50 concentration, the maximum effect previously estimated was not achieved on the isobologram, indicating an antagonism action. Nevertheless, the association of those both fractions in 1:1 or 1:3 ratio demonstrated an increase in antinociceptive activity, classified as synergistic effect. The combination of fractions B and C (3:1; 1:1; and 1:3) significantly reduced abdominal writhing’s, classified as synergistic interactions. The combination of acyclic diterpene fraction (Fraction B) with vouacapans fraction (Fraction C) demonstrated a synergistic pharmacological outcome. Graphical Abstract