Pro- and anti-inflammatory actions of ricinoleic acid: similarities and differences with capsaicin

Abstract

We have investigated the pro- and anti-inflammatory effects of ricinoleic acid (RA), the main active principle of castor oil, in an experimental model of blepharitis induced by intradermal injection of carrageenan in the guinea-pig eyelid and its possible capsaicin-like mode of action on acutely dissociated rat dorsal root ganglia (DRG) neurons in vitro. Topical treatment with RA (10-100 mg/guinea-pig) or capsaicin (1-10 mg/guinea-pig) caused eyelid reddening and oedema. At lower doses (0.3-3 mg/guinea-pig and 0.009-0.09 mg/guinea-pig for RA and capsaicin, respectively) both drugs significantly potentiated the eyelid oedema induced by carrageenan. The tachykinin NK1 receptor antagonist FK 888 (0.59 mg/kg s.c.) abolished the potentiation of carrageenan-induced eyelid oedema induced by either RA or capsaicin. The neutral endopeptidase inhibitor, thiorphan (1.3 mg/kg i.v.) significantly enhanced the potentiation of carrageenan-induced eyelid oedema produced by RA. This potentiating effect was abolished by FK 888. Repeated (8 days) topical application of RA (0.9 mg/guinea-pig) or capsaicin (0.09 mg/guinea-pig) inhibited the carrageenan-induced eyelid oedema. This anti-inflammatory effect was accompanied by a reduction (75%-80% of SP and 46%-51% of NKA) in tachykinin content of the eyelids, as determined by radioimmunoassay. In dissociated rat DRG neurons, RA (0.1 mM for 5 min) significantly inhibited the inward currents induced by application of capsaicin (1 microM) and/or low pH (5.8), without inducing any currents by itself or changing voltage-dependent currents. Moreover, after 24-h incubation, RA (0.1 mM) significantly decreased the capsaicin (1 microM)-induced calcitonin gene-related peptide (CGRP) release from rat DRG neurons, whereas acute drug superfusion did not evoke CGRP release by itself. Summarizing, RA possesses capsaicin-like dual pro-inflammatory and anti-inflammatory properties which are observed upon acute and repeated application, respectively. However, unlike capsaicin, RA does not induce inward current in DRG neurons and it is devoid of algesic properties in vivo.

Byrsonima intermedia A. Juss.: Gastric and duodenal anti-ulcer, antimicrobial and antidiarrheal effects in experimental rodent models

“…The diarrhea inducing by castor oil is known to be due to ricinoleic acid that presents a laxative action, cause local irritation, affects intestinal motility, increases gastrointestinal mucosal permeability, induced damage of intestinal mucosa and also has pro-inflammatory action by increased prostaglandins levels and activated platelet activating factors (Izzo et al, 1998;Vieira et al, 2001;Saito et al, 2002). All rats in the control group (treated with vehicle) after castor oil administration produced copious diarrhea (Table 6).…”

The effects of functional oils on broiler diets of varying energy levels

“…Ricinoleic acid, a natural component of castor oil, has been shown to have anti-inflammatory properties [9]. The CNSL contains the resorcinolic lipid cardol, and resorcinolic lipids have been shown to inhibit both cyclooxygenases [21] and lipoxygenases [22], which are involved in the inflammatory response.…”

“…Castor oil has also been shown to have anti-inflammatory activity [9]. Unfortunately, because castor oil is a laxative when taken orally, its oral use is precluded.…”

Regulation of thermoTRPs by lipids

“…It is commonly found in oils of plant origin as well as in animal cells. 86 With respect to the role of OA in the regulation TRP-channel function, in 2007, Matta and collaborators demonstrated, using 2-electrode voltage-clamp experiments in TRPV1-expressing Xenopus oocytes that relatively high concentrations of OA (50 mM) could achieve small antagonistic effects upon capsaicin activation of this channel. 87 Most recently, we have shown that OA can significantly inhibit responses of heterologously-or natively-expressed TRPV1 channels in excised membrane patches of cells expressing these proteins.…”