Showing papers on "Acacetin published in 1999"

Novel and known constituents from Buddleja species and their activity against leukocyte eicosanoid generation.

Abstract: We have undertaken a systematic survey of the genus Buddleja used in traditional Chinese medicine for antiinflammatory and other indications by testing extracts and isolated natural products for their activity against the enzymes of the arachidonate cascade. This was done by using elicited rat peritoneal leukocytes, a physiologically relevant established whole cell system that expresses both cyclo-oxygenase (COX) and 5-lipoxygenase (5-LOX) activity. Lipophilic extracts of B. globosa roots and B. myriantha stem exhibited inhibitory activities in the 5-LOX and COX enzyme assays, whereas those of B. officinalis flowers, B. yunanesis stems, and B. asiatica stems showed inhibitory activities only against COX. The phytochemical investigation of these extracts, and consequent structure elucidation of isolated compounds using spectroscopic data, led to the isolation from B. globosa of three new terpenoid compounds named dihydrobuddledin A, buddledone A, and buddledone B and four known compounds-buddledins A, B, and C and zerumbone; 12 known compounds from B. officinalis-calceolarioside, campneoside, verbascoside, echinacoside, forsythoside B, angoroside A, crocetin monogentibiosyl ester, acacetin, acacetin-7-O-alpha-L-rhamnopyranosyl (1-6)-beta-D-glucopyranoside, acacetin-7-O-alpha-L-rhamnopyranosyl (1-6)[alpha-L-rhamnopyranosyl (1-2)]-beta-D-glucopyranoside, songarosaponin A, delta-amyrone; and eight known compounds fromB. yunanesis-11,14-dihydroxy-8,11, 13-abietatrien-7-one, beta-sitosterol, verbascoside, echinacoside, forsythoside B, angoroside A, methylcatapol, and sucrose. Tests on the isolated compounds for inhibition of eicosanoid synthesis showed that buddledin A, crocetin monogentibiosyl ester, and acacetin exhibited an inhibitory effect on COX with IC(50) values of 13.7 microM, 28.2 microM, and 77.5 microM, respectively, whereas buddledin A exhibited inhibitory effect on 5-LOX with an IC(50) value of 50.4 microM.

Effect of citrus flavonoids on HL-60 cell differentiation.

Abstract: Twenty-seven Citrus flavonoids were examined for their activity of induction of terminal differentiation of human promyelocytic leukemia cells (HL-60) by nitro blue tetrazolium (NBT) reducing, nonspecific esterase, specific esterase, and phagocytic activities. 10 flavonoids were judged to be active (percentage of NBT reducing cells was more than 40% at a concentration of 40 microM), and the rank order of potency was natsudaidain, luteolin, tangeretin, quercetin, apigenin, 3, 3, '4, '5, 6, 7, 8-heptamethoxyflavone, nobiletin, acacetin, eriodictyol, and taxifolin. These flavonoids exerted their activity in a dose-dependent manner. HL-60 cells treated with these flavonoids differentiated into mature monocyte/macrophage. The structure-activity relationship established from comparison between flavones and flavanones revealed that ortho-catechol moiety in ring B and C2-C3 double bond had an important role for induction of differentiation of HL-60. In polymethoxylated flavones, hydroxyl group at C3 and methoxyl group at C8 enhanced the differentiation-inducing activity.

Antioxidative Activity of Phenolic Compounds in Roasted Safflower (Carthamus tinctorius L.) Seeds

Abstract: Antioxidative compounds contained in roasted safflower seeds were investigated. Six phenolic compounds, N-feruloylserotonin, N-(p-coumaroyl) serotonin, matairesinol, 8′-hydroxyarctigenin, acacetin 7-O-β-D-glucoside (tilianine) and acacetin were isolated and identified from the extract of seeds. The inhibitory effects of six phenolic compounds on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and lipid peroxidation induced by H₂O₂/FeSO₄in rat liver microsomes were determined. Two serotonins showed more potent DPPH radical scavenging activity, and a stronger inhibitory effect on the lipid peroxidation than that of α-tocopherol. In addition, acacetin and matairesinol also considerably inhibited lipid peroxidation, while 2-hydroxy- arctigenin and tilianine were inactive. These results suggest that phenolic compounds, including serotonins, lignans and flavonoids in the roasted safflower seeds can be used as potential dietary natural antioxidants.

Chemical Constituents of Centaurea cuneifolia

Abstract: The whole plant material fo Centaurea cuneifolia Sm. afforded three sesquiterpene lactones; cnicin (1), dehydromelitensin (2) and dehydromelitensin-8-[(2'-a-hydroxy-b- hydroxyethyl)-acryloyl)] (3), the lignan; (-)-arctigenin (4), flavonoids; salvigenin (5), eupatilin (6), jaceosidin (7), acacetin (8), kaemferol (9), 5,7,4'-trihydroxy-3-methylether (10), 5-hydroxy-3',',6,7-tetramethoxyflavone (11) and 5-hydroxy-3',4',7,8-tetramet hoxyflavone (12), a triterpene; a-amyrin and a sterol; b-sitosterol. The structures of the isolates were determined by IR, UV, 1H and 13C NMR and MS spectroscopy.