Hesperidin produces antinociceptive response and synergistic interaction with ketorolac in an arthritic gout-type pain in rats Ana Laura Martínez a,b , Ma. Eva González-Trujano a, ⁎, Marco Chávez d , Francisco Pellicer a , Julia Moreno c , Francisco J. López-Muñoz b a Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Av. Mexico-Xochimilco No. 101, Col. San Lorenzo Huipulco 14370, México, D.F., México b Departamento de Farmacobiología, Cinvestav-Sur, Calz. De los Tenorios No. 235, Col. Granjas Coapa, C.P. 14330, México, D.F., México c Departamento de Análisis Clínicos, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Av. Mexico-Xochimilco No. 101, Col. San Lorenzo Huipulco 14370, México, D.F., México d Unidad de Investigación en Enfermedades, Centro Médico Nacional Siglo XXI, IMSS, Av. Cuauhtémoc 330, Col. Doctores, México, D.F., México abstract article info Article history: Received 25 August 2010 Received in revised form 18 October 2010 Accepted 12 November 2010 Available online 27 November 2010 Keywords: Antinociception Flavonoids Hesperidin Ketorolac Rosmarinus officinalis L. Synergism TRPV1 receptor Hesperidin occurs in greatest concentration in plants from the Rutaceae and Lamiaceae families. In human nutrition it contributes to the integrity of blood vessels and its deficiency in the diet has been linked to abnormal capillary leakiness as well as pain. In this study, the bioflavonoid hesperidin was identified as an active compound in an ethanol extract of the Rosmarinus officinalis aerial parts tested in the pain-induced functional impairment model in the rat (PIFIR) as an assay of inflammatory and chronic nociception similar to that observed in clinical gout. Hesperidin produced a dose-dependent and significant response with an ED 25 = 1666.72 mg/kg in comparison to an ED 25 = 302.90 mg/kg for the extract or an ED 25 = 0.47 mg/kg for the reference drug ketorolac in the PIFIR model. Although the antinociceptive response of R. officinalis was reverted in presence of the opioid antagonist naloxone (10 mg/kg, s.c.) and the 5HT 1A antagonist WAY100635 (0.12 mg/kg, s.c.), the hesperidin response was not modified by naloxone (10 mg/kg), WAY100635 (0.12 mg/kg), bicuculline (1 mg/kg, s.c.), flumazenil (10 mg/kg, i.p.) or caffeine (1 mg/kg, s.c.). Nevertheless, it was reduced in presence of capsazepine (10 or 20 mg/kg, s.c.) suggesting the participation of the TRPV1 receptor, which was reinforced when hesperidin significantly reduced the capsaicin-induced nociceptive response. A synergistic interaction was also observed when antinociceptive doses of hesperidin were combined with those of ketorolac producing 15 combinations mainly in additive and supra-additive responses. These results provide evidence for the antinociceptive activity of hesperidin and demonstrate synergistic response when combined with ketorolac, possibly by involvement of the TRPV1 receptor, suggesting their clinical potential in pain therapy. © 2010 Elsevier Inc. All rights reserved. 1. Introduction Hesperidin is a flavonoid previously called “vitamin P” to indicate that it could decrease capillary permeability and fragility (Morii, 1939). It has been reported that hesperidin prevents vascular leakage through the inhibition of the enzyme hyaluronidase; it also decreases the amount of blood cells and platelet aggregation (Beiler and Martin, 1948; Garg et al., 2001). Besides its effect on vascular permeability, this flavonoid exhibits a wide range of pharmacological activities such as sedative (Fernández et al., 2005; Guzmán-Gutiérrez and Navarrete, 2009), antioxidant (Hirata et al., 2005; Zhang et al., 2002), anticarcinogenic (Hirata et al., 2005; Tanaka et al., 1997), as well as exhibiting anti-inflammatory and analgesic properties (Hirata et al., 2005; Galati et al., 1994; Benavente-García and Castillo, 2008). A preventive effect was also previously reported on the development of adjuvant arthritis, a rat model of rheumatoid arthritis by using Freund's complete adjuvant (Guardia et al., 2001; Li et al., 2008). Hesperidin is abundantly found in citrus fruits (family Rutaceae) (Benavente-García and Castillo, 2008) and in many plants of the genera Lamiaceae (Garg et al., 2001; Kokkalou and Kapetanidis, 1988). Rosmarinus officinalis L. is a plant species of the family Lamiaceae; it is an aromatic evergreen shrub native to the Mediterranean area and now grown in many countries. It is well-known around the world and widely used for flavoring food and beverages, as well as an ingredient in cosmetic products (Al-Sereiti et al., 1999; Altinier et al., 2007); in folk medicine it is mainly used as an antispasmodic, in renal colic, dysmenorrhoea and abdominal colic (Al-Sereiti et al., 1999; Peng et al., 2007). In Mexico, R. officinalis aerial parts are prepared as maceration in ethanol and used in topical administration to relief rheumatic pain. A tea made of the boiled leaves is used to improve digestion and to relief stomach-ache (Martínez, 1989). Several phytochemical studies have shown that R. officinalis contains essential oils, phenols, diterpenoids, terpenoids and especially flavonoids (Okamura et al., 1994; Zeng et al., 2001). Flavonoids, part of a large Pharmacology, Biochemistry and Behavior 97 (2011) 683–689 ⁎ Corresponding author. Tel.: +52 55 56 55 28 11; fax: +52 55 56 55 99 80. E-mail address: evag@imp.edu.mx (M.E. González-Trujano). 0091-3057/$ – see front matter © 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.pbb.2010.11.010 Contents lists available at ScienceDirect Pharmacology, Biochemistry and Behavior journal homepage: www.elsevier.com/locate/pharmbiochembeh