Bioactive Constituents of Chinese Natural Medicines. VII. Inhibitors of Degranulation in RBL-2H3 Cells and Absolute Stereostructures of Three New Diarylheptanoid Glycosides from the Bark of Myrica rubra.

Abstract

The Myricaceae plant Myrica rubra SIEB. et ZUCC. is widely distributed in China, Taiwan, Japan and Korea. The bark of M. rubra (Myricae cortex) has been used locally as an astringent, antidote, and antidiarrheic in Japanese folk medicine, and has also been used externally for burns and skin diseases in Chinese traditional medicine. Previously, several flavonoids, 2) tannins, 2) triterpenes, 3) and diarylheptanoids [4][5][6][7][8] were isolated from the bark of M. rubra. Pharmacological studies of this natural medicine have reported that its methanolic extract showed protective effects on CCl 4Ϫ and a-naphthylisothiocyanate-induced liver injury, 9) whereas the 50% aqueous ethanolic extract and some constituents inhibited melanin biosynthesis 10) and showed anti-androgenic activity. 11)In the course of characterization studies on the bioactive constituents of Chinese natural medicines, 1,12) we have iso-

Medicinal Foodstuffs. XXXI. Structures of New Aromatic Constituents and Inhibitors of Degranulation in RBL-2H3 Cells from a Japanese Folk Medicine, the Stem Bark of Acer nikoense.

“…(1H, m, 3-H Research Resources Bank (Osaka, Japan)] were evaluated by the method reported previously. 8,33,34) Briefly, RBL-2H3 cells were dispensed into 24-well plates at a concentration of 2ϫ10 5 cells/well using Eagle's minimum essential medium (MEM, Sigma) containing fetal calf serum (10%), penicillin (100 units/ml), streptomycin (100 mg/ml), and 0.45 mg/ml of anti-DNP IgE, and these were incubated overnight at 37°C in 5% CO 2 for sensitization of the cells. Then the cells were washed twice with 500 ml of siraganian buffer [119 mM NaCl, 5 mM KCl, 0.4 mM MgCl 2 , 25 mM piperazine-N,NЈ-bis(2-ethanesulfonic acid) (PIPES), and 40 mM NaOH, pH 7.2], then incubated in 160 ml of siraganian buffer [5.6 mM glucose, 1 mM CaCl 2 , and 0.1% bovine serum albmin (BSA) were added] for an additional 10 min at 37°C.…”

“…The IR spectrum of 4 showed absorption bands at 3453, 1595, 1508, and 1032 cm As a part of our characterization studies on the bioactive components of natural medicines, we previously reported several inhibitors of the release of b-hexosaminidase such as diaylheptanoids, 8) diterpenes, 33) and flavonoids. 34) In our continuous search for antiallergic principles from natural sources, we examined the effects of constituents from the stem bark of A. nikonense on the release of b-hexosaminidase induced by dinitrophenylated bovine serum albumin (DNP-BSA) from RBL-2H3 cells sensitized with anti-DNP IgE ( Table 2).…”

“…2,6) During the course of our studies on bioactive constituents of natural medicines [7][8][9][10][11][12][13] and medicinal foodstuffs, [14][15][16][17][18][19] we have reported three new cyclic diarylheptanoids called acerosides B 1 (5) and B 2 (6) and aceroketoside (7) from the stem bark of A. nikoense as well as the inhibitory effects of the principal diarylheptanoids on nitric oxide (NO) production in lipopolysaccharide (LPS)-activated macrophages. 1) As a continuation of the characterization studies on bioactive constituents of the stem bark of A. nikoense, we have isolated four new aromatic compounds called rhododendroketoside (1), (Ϫ)-sakuraresinoside (2), acernikol (3), and nikoenoside (4) together with six known compounds (9, 14, 17, 27-29).…”

“…[2][3][4][5] In addition, the methanolic extract was reported to have hepatoprotective effects and (ϩ)-rhododendrol (15) was isolated as the active principle. 2,6) During the course of our studies on bioactive constituents of natural medicines [7][8][9][10][11][12][13] and medicinal foodstuffs, [14][15][16][17][18][19] we have reported three new cyclic diarylheptanoids called acerosides B 1 (5) and B 2 (6) and aceroketoside (7) from the stem bark of A. nikoense as well as the inhibitory effects of the principal diarylheptanoids on nitric oxide (NO) production in lipopolysaccharide (LPS)-activated macrophages. …”

Pharmacological Profile of the Novel Anti-inflammatory Corticosteroid NS-126, a Therapeutic Agent for Allergic Rhinitis

“…Degranulation : RBL-2H3 cells, an adherent rat basophilic leukemia cell line (Health Science Research Resources Bank, Osaka), were used as a mast-cell model, and degranulation was assessed by measuring the release of β -hexosaminidase essentially as previously described (17). RBL-2H3 cells in EMEM containing 10% FCS were seeded into 24-well culture plates at a density of 2 × 10 5 cells in 1 ml and incubated overnight at 37°C in a humidified atmosphere containing 5% CO 2 with excess monoclonal anti-DNP IgE (50 ng/ml) to sensitize the cells.…”