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Antinociceptive Activity of Thymoquinone and its Structural Analogues: A Structure-Activity Relationship Study

DP de Sousa
FFF Nóbrega
CCMP Santos
RB Benedito
YW Vieira
MP Uliana
TJ Brocksom
RN de Almeida


Purpose: To investigate the structural features that influence the antinociceptive activity of thymoquinone and their structural analogues.
Methods: The quinones were prepared by an oxidation procedure using molecular oxygen and catalysis with [CoII(salen)] from the respective phenols. The antinociceptive activity of para-benzoquinones (10 mg/kg, ip) was evaluated using formalin test in mice. Vehicle (5 % Tween 80) or morphine (10 mg/kg) were used as control group and standard drug, respectively. The amount of time spent licking the injected paw was considered as the nociceptive response.
Results: Among the compounds tested, five para-benzoquinones showed antinociceptive activity. The 2-isopropyl-para-benzoquinone presented the highest potency in first and second phases and produced a near-maximal inhibition (p < 0.001) in the formalin test, similar to morphine (p < 0.001).
Conclusion: Our experimental results show that by appropriate structural modification of parabenzoquinones it may be possible to develop novel analgesic drugs.

Keywords: Quinones, Antinociceptive activity, Analgesic, Central nervous system, Structure-activity relationship, Medicinal plant.

Journal Identifiers

eISSN: 1596-9827
print ISSN: 1596-5996