This paper describes the antinociceptive action of 13,118-binaringenin (GB-1a), a biflavonoid isolated from Clusia columnaris and present in several plants of the family Guttiferae, in a writhing test and a formalin test. It was found that it exhibits potent and dose-related antinociceptive action in both experimental models, with ID50 values of 22 mumol/kg against the writhing test and 28 mumol/kg against the second phase of the formalin test. It was more potent than some well-known analgesic drugs used as reference. Based on a hot-plate test its mechanism of action seems to be unrelated with the opioid receptors.

This work describes the antinociceptive effect of a triterpene glycoside, niga-ichigoside F1 (1), obtained from an EtOAc extract of the aerial parts of Rubus imperialis. When evaluated against an HOAc-induced writhing model, it exhibited an ID(50) value of 3.1 mg/kg (ip). Moreover, in a formalin-induced pain model, both phases of pain were inhibited by compound 1, with ID(50) values of 2.6 (first phase) and 2.7 (second phase) mg/kg, (ip), respectively.

2002 carboxylic acid derivatives carboxylic acid derivatives (naphthalene compounds) Q 0950 37 -099 4-Nitro-1,8-naphthalimides Exhibit Antinociceptive Properties. -The synthesis of title compounds (I) and a related compound (II) from the corresponding anhydrides and evaluation of their antinociceptive and analgesic activities is described. The compounds studied show promising antinociceptive activity and may be used as leads to obtain new substances with analgesic potential. -(DE SOUZA, M. M.; CORREA, R.; CECHINEL-FILHO, V.; GRABCHEV, I.; BOJINOV, V.; Pharmazie 57 (2002) 6, 430-431; Nucl. Invest. Quim.-Farm., Univ. Vale do Itajai, Itajai, 88302 Sao Carlos, Brazil; EN)

In this paper, we describe the antinociceptive activity, molecular modeling and in silico ADMET screening of a series of sulphonyl-hydrazone and sulphonamide imidobenzene derivatives. Among these compounds, the sulphonyl-hydrazones 9 and 11 showed the most potent analgesic activity (ID(50) = 5.1 and 6.8 μmol/kg, respectively). Interestingly, all derivatives evaluated in this study have a better analgesic profile than the control drugs, acetyl salicylic acid and acetaminophen. Derivative 9 was the most promising compound; with a level of activity that was 24 times higher than the control drugs. Our SAR study showed a relationship among the distribution of the frontier orbital HOMO coefficients, HOMO-LUMO energy gap of these molecules and their reactivity. The best analgesic compounds (including 6, 9, 10, 11 and 12) fulfilled the Lipinski "rule-of-five", which is theoretically important for good drug absorption and permeation.