Anti-Allergic Properties of the Natural PAF Antagonist Yangambin

Abstract

In this study we examined the ability of the furofuran lignan yangambin to influence the local and systemic responses induced by antigen or PAF in actively sensitized or normal rats. Given intraperitoneally 1 h before stimulation, yangambin inhibited the pleural neutrophil and eosinophil infiltration evoked by the i.pl. injection of PAF or antigen into normal or 14 daysensitized rats whereas plasma exudation evoked by both stimuli was unaffected. The pleural neutrophil influx (6 h) after LTB4 stimulation was also significantly inhibited by yangambin. We also evidenced that the hemoconcentration, thrombocytopenia, and leucocytosis noted after i.v. PAF were all attenuated by yangambin. In actively sensitized rats, pretreatment with yangambin failed to modify the antigen-induced hemoconcentration and leucocytosis, but dose-dependently abrogated the thrombocytopenia noted 1 h post-stimulation. In vitro, the anaphylactic contraction of longitudinal jejunal segments to antigen challenge was significantly inhibited by yangambin (10(-5)-10(-4) M). Likewise, the contraction of jejunal segments from normal rats to PAF was markedly blocked by yangambin under conditions where the response to 5-hydroxytryptamine (5-HT) was not altered. In conclusion, our results show that antigen- and PAF-induced pleural neutrophil and eosinophil accumulation, but not exudation, is sensitive to treatment with yangambin. In addition, yangambin also suppressed the pleural neutrophil infiltration triggered by LTB4 as well as the blood thrombocytopenia and intestinal anaphylaxis elicited by antigen in rats. Thus, our findings indicate that yangambin shows an antagonistic action on receptors other than those of PAF, i.e., LTB4, and strongly suggest that it may be a useful drug in the treatment of some allergic inflammatory responses.

GC-MS analysis and cardiovascular activity of the essential oil of Ocotea duckei

“…Previous reports on Ocotea duckei described the isolation of alkaloids Silva et al, 2002;Morais et al, 1998a) and lignoids (Morais et al, 1996;Morais et al, 1998b;Morais et al, 1999;Barbosa-Filho et al, 1999). Yangambin, the main lignoid isolated from this species has shown many pharmacological properties, such as: (a) a selective platelet activating factor (PAF) receptor antagonist, observed in several in vitro and in vivo experimental models (Castro-Faria-Neto et al, 1995a,b;Herbert et al, 1997), (b) an effective pharmacological agent against cardiovascular collapse and mortality in endotoxin shock Ribeiro et al, 1996;Araújo et al, 2001), (c) an anti-allergic effect (Serra et al, 1997), (d) increased sleeping time induced by pentobarbital and the blockage of convulsions induced by pentylenotetrazole (Almeida et al, 1995;Pachú et al, 1993), (e) yangambin was not mutagenic when tested using strains of Salmonella typhimurium (Marques et al, 2003), (f) topical treatment of eggs and fi rst instars with yangambin as well as feeding larvae with a yangambin-treated diet resulted in inhibition of postembryonic development, morphological alteration, and oviposition reduction (Cabral et al, 2007a,b), (g) yangambin presented antileishmanial activity against promastigotes forms of L. chagasi and L. amazonensis (Monte-Neto et al, 2007) and antimicrobial activity against Escherichia coli (Antunes et al, 2006). This is the fi rst report of the composition of the essential oils obtained from the fruits, leaves, stem and roots of Ocotea duckei, as well as the pharmacological activity on the cardiovascular system.…”

Antiallergic Activity of Aqueous Extracts and Constituents of Taxus yunnanensis

“…The lignans and flavonoids of polyphenol are widely distributed in the plant kingdom, and have been recognized to have various biological activities including antiallergic actions, and various in vitro and in vivo studies of the antiallergic effect have been reported. [1][2][3][4] Taxus yunnanensis CHENG et L. K. FU, which belongs to the plant family Taxaceae is widely distributed in the Yunnan Province of the People's Republic of China and commonly known as "Yunnan Hongdoushan". The wood of Taxus yunnanensis has been used in traditional Chinese medicine by several ethnic societies in the Yunnan Province for the treatment of kidney problems and diabetic conditions.…”

Inhibitory Activity of Lignan Components from the Flower Buds of Magnoliae fargesii on the Expression of Cell Adhesion Molecules.

“…anti-allergic properties of yangambin, 11) a natural PAF antagonist, PAF receptor antagonism of a semisynthetic lignan 12) and TNF-a production by lignans from the rhizomes of Coptis japonica in LPS-stimulated RAW264.7 cells. 13) We have studied the modulation of expression of cell adhesion molecules, another important target for the treatment of inflammation-related diseases, in endothelial cells and leukocytes by natural products.…”