<i>Bixa orellana</i> Leaves Extract Inhibits Bradykinin-Induced Inflammation through Suppression of Nitric Oxide Production

Abstract

Objective: The present study was conducted to assess the anti-inflammatory effect of a crude aqueous extract of Bixa orellana leaves (AEBO) and to examine the possible involvement of nitric oxide (NO) in its anti-inflammatory mechanism. Materials and Methods: The air-dried, powdered leaves were soaked in distilled water (1:20 w/v) at 50°C for 24 h and the supernatant obtained was freeze-dried (yield 8.5% w/w). The dosage was recorded as the mass of extract per kg b.w. of rats in all inflammatory assays (bradykinin-induced paw edema, peritoneal vascular permeability and NO assay). Results: Pretreatment with AEBO for 4 consecutive days exhibited significant inhibitory activity against inflammatory models, the bradykinin-induced hind paw edema model and bradykinin-induced increased peritoneal vascular permeability at both doses in dose-dependent manner. In addition, AEBO was also found to significantly suppress the production of NO at doses of 50 and 150 mg/kg. Conclusion: This study provides scientific data to support the traditional use of B. orellana leaves in treating inflammation. Results from this study suggest that AEBO exerts anti-inflammatory effects. Part of this anti-inflammatory effect may be associated with its antibradykinin activity and may be related to a reduction of the NO production.

Suppressions of Serotonin-Induced Increased Vascular Permeability and Leukocyte Infiltration byBixa orellanaLeaf Extract

“…Leaves of Bixa orellana have been used in the traditional systems of medicine for treating various ailments as antifungal [23], antimicrobial [24], antiplasmodial [15], antimalarial [25], antihypertension, antidiabetes, and antijaundice agent [26]. Recently, our studies also proved that aqueous extract of B. orellana leaves was effective against bradykinin and histamine induced acute inflammation [16, 27]. However, the pharmacology of the anti-inflammatory profile of B. orellana leaves has still not been fully established.…”

Chemical constituents and antihistamine activity of Bixa orellana leaf extract

“…Indeed, when bradykinin was later used to induce acute inflammation in the same rat models, it was confirmed that up to 82% of the increased vascular permeability was successfully alleviated upon administration of AEBO [6]. Histamine is one of the inflammogens that contributes to acute inflammation and increase of vascular permeability [15].…”

“…B. orellana leaves were dried in an oven at 60°C for three consecutive days and ground into fine powder. The aqueous extract was obtained by mixing the powder together with distilled water at ratio 1:20, and kept in a water bath (40°C) for 24 h, followed by filtration [6]. The filtrate was kept at −80°C and lyophilized using a freeze drier, yielding 8.5% (w/w).…”

“…The bark and root can be used to treat fever; the leaves are used as a cure for snakebites, jaundice, diabetes and hypertension, especially in Trinidad and Tobago, while also being used as a postpartum medicine in Malaysia [2]. The leaves of Bixa orellana have been reported to have antimicrobial [3], antifungal, antileishmanial [4], anticonvulsant, analgesic [5] and anti-inflammatory activities [6]. …”

“…We have previously reported the ability of the aqueous extract of Bixa orellana (AEBO) in suppressing inflammation induced by carrageenan (data not published) and bradykinin [6]. This study aimed to investigate whether the anti-inflammatory activity of AEBO was caused by the blocking of histamine action, and to determine the involvement of two biochemical mediators, NO and vascular endothelial growth factor (VEGF), in the reduction of inflammation by AEBO.…”