Inhibition of Leukotriene Synthesis by Honokiol in Rat Basophilic Leukemia Cells

Abstract

The effects of honokiol, a diphenyl compound extracted from a Chinese herbal medicine, on leukotriene (LT) synthesis were evaluated in rat basophilic leukemia (RBL) cells. The production of LTC₄ and LTB₄ stimulated by the Ca²⁺ ionophore A23187 was measured in RBL-1 cells by high-performance liquid chromatography. Honokiol inhibited the production of LTC₄ and LTB₄ stimulated by A23187 in RBL-1 cells. Honokiol did not inhibit either phospholipase A2 activity, measured by the release of ³H-arachidonic acid (AA), or LTC₄ synthase and LTA₄ hydrolase activities, measured with LTA₄-free acid as substrate. The synthesis of LTC₄ and LTB₄ from AA in RBL-1 cell lysates in the presence of Ca²⁺ was inhibited by honokiol. These results indicate that honokiol blocks LT synhesis by inhibiting 5-lipoxygenase activity. Honokiol also inhibited immunoglobulin E-mediated production of these LTs in RBL-2H3 cells, which was measured by a specific radioimmunoassay (RIA). These results suggest that honokiol may exhibit antiallergic actions by inhibiting LT synthesis in immediate-type hyperreactivity.

Honokiol Inhibits Osteoclast Differentiation and Function in Vitro

“…Honokiol is reported to have various activities, including anti-oxidative, anti-inflammatory, anti-allergic, anti-angiogenic and anti-tumor properties. [10][11][12][13][14][15] Previous reports have shown that honokiol inhibits nitric oxide production by lipopolysaccharide-activated RAW264 cells 24) and mouse macrophages. 25) Recently, honokiol has been shown to potentiate TNF-a-induced apoptosis in chronic myelogenous leukemia KBM5 cells, suppress TNF-a-induced tumor cell invasion, and inhibit RANKLinduced osteoclastogenesis in RAW264 cells, although the mechanism of action of honokiol on osteoclastogenesis remains unclear.…”

Antimicrobial activity of honokiol and magnolol isolated from Magnolia officinalis

“…The biological activities of these compounds include potent inhibition of lipid peroxidation (Lo et al, 1994;Haraguchi et al, 1997). scavengers of hydroxyl radicals (Taira et al, 1993), inhibition of leukotriene synthesis in leukaemia cells (Hamasaki et al, 1996) and inhibition of UV-induced mutations (Fujita and Taira, 1994). They are considered to be important active components of medicinal plants.…”

Derivatives of schisandrin with increased inhibitory potential on prostaglandin E2 and leukotriene B4 formation in vitro

“…Baillon (Wu Wei Zi, Magnolia Vine, Schisandraceae) is a plant commonly used in traditional Chinese medicine and also widely used in Russia, possessing various biological activities like antihepatotoxic, antibacterial and cardiovascular effects, as well as effects on CNS, uterus and immune regulatory actions. 1,2 The fruits of Schisandra chinensis are a rich source of lignans with concentrations ranging from 7.2% to 19.2% depending on the geographical origin and on the harvesting time. 3 Main constituents such as schisandrin (1), gomisin A (2), angeloylgomisin H (3), and tigloylgomisin H (4), which contain a dibenzo[a,c]cylooctadiene skeleton with a high degree of methoxylation/dioxomethylene bridges at the biphenyl system have been isolated and fully characterized by the group of Ikeya.…”

“…18 Biphenyl-neolignans such as magnolol and honokiol and derivatives thereof have been shown to act as potent inhibitors of COXisoenzymes and 5-LOX. [19][20][21][22] In these compounds the biphenyl axis is more or less flexible, whereas in S. chinensis lignans this torsion angle is fixed by the presence of a cyclooctadiene ring. Apart from some reports indicating minor activities, no detailed studies revealing significant activity of Schisandra lignans and related structures on COX/LOX were carried out to date to the best of our knowledge.…”