Chemistry of toxic range plants. Highly oxygenated flavonol methyl ethers from Gutierrezia microcephala

The perennial American desert shrub, Gutierrezia microcephala, contains 20 flavonol methyl ethers displaying nine different oxygenation patterns. These include 11 new flavonols: 5,7-dihydroxy-3,6,8,3′,4′,5′-hexamethoxyflavone, 5,7,4′-trihydroxy-3,6,8,3′,5′-pentamethoxyflavone, 5,7,3′-trihydroxy-3,6,8,4′,5′-pentamethoxyflavone, 5,7,2′,4′-tetrahydroxy-3,6,8,5′-tetramethoxyflavone, 5,7,3′,4′-tetrahydroxy-3,6,8-trimethoxyflavone, 5,7,8,3′,4′-pentahydroxy-3,6-dimethoxyflavone, 3,5,7,3′,4′-pentahydroxy-6,8-dimethoxyflavone, 5,7,4′-trihydroxy-3,6,8-trimethoxyflavone, 5,7,8,4′-tetrahydroxy-3,3′-dimethoxyflavone, 5,7,8,3′,4′-pentahydroxy-3-methoxyflavone and 5,7,8,4′-tetrahydroxy-3-methoxyflavone. In addition, the following known flavonols were isolated: 5,7-dihydroxy-3,8,3′,4′,5′-pentamethoxyflavone, 5,7,4′-trihydroxy-3,8-dimethoxyflavone, 5,7,4′-trihydroxy-3,8,3′-trimethoxyflavone, 5,7,3′,4′-tetrahydroxy-3,8-dimethoxyflavone, 5,7,4′-trihydroxy-3,6,3′-trimethoxyflavone, 5,7,3′,4′-tetrahydroxy-3-methoxyflavone, 5,4′-dihydroxy-3,6,7,8,3′-pentamethoxyflavone, 5,7,4′-trihydroxy-3,6,8,3′-tetramethoxyflavone and 3,5,7,4′-tetrahydroxy-6,8,3′-trimethoxyflavone.     

Antioxidant and α-Amylase Inhibitory Compounds from Aerial Parts of Varthemia iphionoides Boiss

Various extracts of aerial parts of Varthemia (Varthemia iphionoides Boiss) were investigated for radical-scavenging activity, antioxidative activity, and porcine pancreas α-amylase inhibitory activity. The ethanol and water extracts showed a pronounced 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, with inhibition of about 90% at a concentration of 100 μg/ml, and α-amylase inhibitory activity of about 70% at a concentration of 200 μg/ml by the 2-chloro-4-nitrophenyl α-maltotrioside (CNP-G₃) degradation method. The ethanol extract was purified by column chromatography to give seven 3-methoxyflavones (1–7) and eudesmane sesquiterpene, selina-4,11(13)-dien-3-on-12-oic acid (8). The structures of these compounds were established by NMR, MS, and UV spectroscopy. Of 3-methoxyflavones, 5,7,4′-trihydroxy-3,6-dimethoxyflavone (1), 5,7,4′-trihydroxy-3,3′-dimethoxyflavone (2), and 5,4′-dihydroxy-3,7,3′-trimethoxyflavone (3,7,3′-tri-O-methyl-quercetin) (7) exhibited pronounced radical-scavenging activity. The antioxidative activity in the linoleic acid system was considerable in compounds 1, 2, and 5,4′-dihydroxy-3,6,7-trimethoxyflavone (4). Compounds 1, 2, 4, 5 (5,7,4′-trihydroxy-3-methoxyflavone), and 6 (5,4′-dihydroxy-3,7-dimethoxyflavone) showed markedly high inhibitory activity against porcine pancreas α-amylase. Eudesmane sesquiterpene did not show any activity.     

Fungitoxic dihydrofuranoisoflavones and related compounds in white lupin,Lupinus albus

Chromatographic investigation of a methanolic extract of white lupin roots has revealed the presence of six new dihydrofuranoisoflavones (lupinisoflavones A-F). Three monoprenylated (3,3-dimethylallyl-substituted) isoflavones (wighteone, luteone and licoisoflavone A), two diprenylated isoflavones [6,3′-di(3,3-dimethylallyl)genistein (lupalbigenin) and 6,3′-di(3,3-dimethylallyl)-2′-hydroxygenistein (2′-hydroxylupalbigenin)] and two pyranoisoflavones (parvisoflavone B and licoisoflavone B) have also been isolated from the same source. In addition to genistein, leaf extracts of L. italbus contain 3′-O-methylorobol which is presumed to be the precursor of lupisoflavone [5,7,4′-trihydroxy-3′-methoxy-6-(3,3-dimethylallyl)isoflavone]. Probable biogenetic relationships between the prenylated, and dihydrofurano-and pyrano-substituted isoflavones in roots and leaves of L. albus are briefly discussed.     

C-methyl phenolics from Qualea species

The trunk wood of Qualea labouriauana contains, besides (2R)-5,7,4′-trihydroxy-3′-methoxy-6,8-dimethylflavanone, (2R)-5,7,4′-trihydroxy-8-methylflavanone, the biosynthetically interesting 2,2′-dihydroxy-4,6,4′,6′-tetramethoxy-3,3′-dimethylbenzophenone. From the trunk wood extract of Q. paraensis the first named flavanone crystallized out directly.     

Flavonoids from Artemisia ludoviciana var. ludoviciana

Nineteen flavonoids were isolated from Artemisia ludoviciana var. ludoviciana, including a new 2′- hydroxy- 6-methoxyflavone, 5,7,2′,4′-tetrahydroxy-6,5′-dimethoxyflavone. The known compounds include quercetagetin 3,6,3′,4′-tetramethyl ether, eupatilin, 5,7-dihydroxy-3,6,8,4′-tetramethoxyflavone, luteolin 3′,4′-dimethyl ether, jaceosidin, 5,7,4′-trihydroxy-3,6-dimethoxyflavone, tricin, hispidulin, chrysoeriol, kaempferol 3-methyl ether, apigenin, axillarin, eupafolin, selagin and luteolin together with three flavones which were previously isolated for the first time from Artemisia frigida: 5,7,4′-trihydroxy-6, 3′,5′-trimethoxyflavone, 5,7,3′-trihydroxy-6,4′,5′-trimethoxyflavone and 5,7,3′,4′-tetrahydroxy-6,5′- dimethoxyflavone.     

New prenylated isoflavones and a prenylated dihydroflavonol from Millettia pachycarpa

Extraction of Millettia pachycarpa Benth. gave 5,7,4′-trihydroxy-6,8-diprenylisoflavone (1a), 5,7,4′-trihydroxy-6,3′-diprenylisoflavone (2a), 5,7,3′,4′-tetrahydroxy-6,8-diprenylisoflavone (3a) and (2R, 3R)-5,4′-dihydroxy-8-prenyl-6″,6″-dimethylpyrano[2″,3″: 7,6]-dihydroflavonol (4a) whose structures were established by chemical transformations and spectroscopic means. Pectolinarigenin and salvigenin were isolated from Buddleia macrostachya Benth.     

New isoflavonoids related to kievitone from Phaseolus vulgaris

The new isoflavonoids 5,7,2′,4′-tetrahydroxy-8-(3,3-dimethylallyl)isoflavone (2,3-dehydrokievitone) and 7,2′,4′-trihydroxy-8-(3,3-dimethylallyl)isoflavanone (5-deoxykievitone) have been isolated from fungus-inoculated Phaseolus vulgaris pod tissue and from the inoculation droplets. A third isoflavonoid was tentatively identified as 1″,2″-dehydrocyclokievitone and appears to be a metabolite of the phytoalexin kievitone.     

Flavonoids from Millettia pulchra

Chemical examination of Millettia pulchra yielded (?)-maackiain, (?)-pterocarpin, (?)-sophoranone and the new compounds (6S, 6aS, 11aR)-6α-methoxypterocarpin, (6S, 6aS,11aR)-6α-methoxyhomopterocarpin, (2S)5,7,4′-trihydroxy-8,3′,5′-triprenylflavanone, (2R,3R)7,4′-dihydroxy-8,3′,5′-triprenyldihydroflavanol, 5,7,2′,4′-tetrahydroxy-6,3′-diprenylisoflavone and 5,7,4′-trihydroxy-2′-methoxy-6,3′-diprenylisoflavone.     

外来入侵植物假臭草的黄酮类成分研究

从外来入侵植物假臭草的70%乙醇提取物的乙酸乙酯萃取物中分离得到5个黄酮化合物,利用波谱方法鉴定为5,6,7,4′-四甲氧基黄酮(1),7-羟基-5,6,4′-三甲氧基黄酮(2),4′-羟基-5,6,7-三甲氧基黄酮(3),5,4′-二羟基-6,7-二甲氧基黄酮(4),5,7,4′-三羟基-6-甲氧基黄酮(5).化合物1～5均首次从该植物中分离得到.     

Erymildbraedin A and B,two novel cytotoxic dimethylpyrano-isoflavones from the stem bark of Erythrina mildbraedii: evaluation of their activity toward endocrine cancer cells

Two new dimethylpyrano-isoflavones, named erymildbraedin A (4) and B (5), were isolated from the stem bark of the Cameroonian medicinal plant Erythrina mildbraedii, along with four known ones, the linear congeners, scandenone (1), erysenegalinsein M (2), 5,4′-dihydroxy-2′-methoxy-8-(3,3-dimethylallyl)-2″,2″-dimethylpyrano[5,6:6,7]isoflavone (3), and the angular isoflavone eryvarin B (6), and two other compounds, fraxidin and scoparone. Their structures were elucidated by the usual spectroscopic methods and isoflavone effects on the growth of human breast, prostate, and endometrial adenocarcinoma cells were determined. Isoflavones 1, 3, and 6 strongly inhibited the growth of all three cell lines, supporting the notion that a non-oxidized isoprenyl group at C-8 is requisite for cytotoxic activity.     

Labdane derivatives and flavones from Gutierrezia dracunculoides

An investigation of the aerial parts of Gutierrezia dracunculoides afforded, in addition to known compounds, three new labdane derivatives, all related to lambertianic acid, 17-hydroxy- and 17-acetoxylambertianic acid and 7α- hydroxylambertianic acid, two esterified and three highly oxygenated flavones, 5,7,4′-trihydroxy-3,3′-dimethoxy- flavone-4′-O- [2-methylbutyrate] and isovalerate, 3′,5′-dihydroxy-3,5,6,7,8,4′-hexamethoxyflavone, 5,3′,5′-trihydroxy- 3,6,7,8,4′-pentamethoxyflavone and 5,7,3′,5′-tetrahydroxy-3,6,8,4′-tetramethoxyflavone. The structures were elucidated by spectroscopic methods and a few chemical transformations.     

Three highly oxygenated flavone glucuronides in leaves of Spinacia oleracea

Droplet counter-current chromatographic separation and subsequent TLC demonstrated the existence of at least 14 phenolics in the leaves of Spinacia oleracea. Three have now been isolated and identified, respectively, as the 4′-glucuronides of 5,7,4'-trihydroxy-3,6,3′-trimethoxyflavone (jaceidin), 5,3′,4′-trihydroxy-3-methoxy-6:7-methylene-dioxyflavone and 5,4′-dihydroxy-3,3′-dimethoxy-6:7-methylenedioxyflavone.     

Psorantin,a unique methylene linked dimer of vismin and kenganthranol E,two anthranoid derivatives from the fruits of Psorospermum aurantiacum (Hypericaceae)

Two prenylated anthranoids, psorantin and kenganthranol E, were isolated from the fruit of Psorospermum aurantiacum together with the known compounds ferruginin B, vismin, vismion D, haronginanthrone, kenganthranol B, kenganthraquinone, 1,7-dihydroxyxanthone, paradisiol, fridelin, fridelinol and betulinic acid. Their structures were determined on the basis of spectral data and by comparison with data reported in the literature as well as with authentic specimens for the known compounds. The structures of the new compounds were determined as bis-[3,8,9-trihydroxy-6-methyl-4,4-bis-(3,3-dimethylallyl)anthracenyl]methane (1) and 1,8,10-trihydroxy-6-methyl-4,5-bis-(3,3-dimethylallyl)-2,3-(2,2-dimethylpyrano)anthrone (2). Psorantin (1) is a dimer of vismin formed through a methylene linkage. The two new compounds when tested against the microbial strains Bacillus megaterium, Escherichia coli, Chlorella fusca and Microbotryum violaceum showed no activity.     

Flavonoids from Gutierrezia texana var. texana

Eleven flavonoids, including two new compounds, were isolated from Gutierrezia texana: the structures of the new compounds are 5,7,2′,5′-tetrahydroxy-3,4′-dimethoxyflavone and 5′-acetoxy-5,7,2′-trihydroxy-3,4′-dimethoxyflavone. The nine known compounds are 5,4′,5′-trihydroxy-3,6,7,8-tetramethoxyflavone, 5,7,2′,5′-tetrahydroxy-3,6,4′-trimethoxyflavone, 5,7,3′-trihydroxy-3,4′-dimethoxyflavone, 5,7,3′,4′-tetrahydroxyflavone, 3,5,7,3′,4′- pentahydroxyflavone, 5,7,3′,4′-tetrahydroxy-3-methoxyflavone, 5,6,7,3′,4′,-pentahydroxy-3-methoxyflavone, 5,7,3′,4′-tetrahydroxy-3-methoxyflavone 7-O-glucoside and 3,5,7,3′,4′-pentahydroxyflavanone.     

艾纳香化学成分的研究

从艾纳香(Blumea balsamifera DC.)中分离得到12个化合物,通过理化性质和波谱数据分析分别鉴定为;商路素(1),花椒油素(2),2,4-二羟基-6-甲氧基苯乙酮(3),5,7-二羟基色原酮(4),金丝桃苷(5),异槲皮苷(6),3′,4′,5,7-四羟基-3-甲氧基黄酮(7),槲皮素(8),槲皮素-3′-甲氧基-3-O-β-D-半乳吡喃糖苷(9),4′,5,7-三羟基-3,3′-二甲氧基黄酮(10),3,5,7-三羟基-3′,4′-二甲氧基黄酮(11),木犀草素(12).其中,化合物3-7和9- 11为首次从该属植物中分离得到.     

海南栽培肾茶的化学成分研究

为了解肾茶(Clerodendranthus spicatus)的化学成分,从海南栽培肾茶地上部分分离得到11个化合物,经波谱分析分别鉴定为:吐叶醇(1)、丁香脂素(2)、3,4-二羟基苯乙醇(3)、甜橙素(4)、5,6,7,4′-四甲氧基黄酮(5)、5-羟基-6,7,3′,4′-四甲氧基黄酮(6)、6-羟基-5,7,4′-三甲氧基黄酮(7)、5-羟基-6,7,3′,4′-四甲氧基黄烷酮(8)、3,3′,5-三羟基-4′,7-二甲氧基-二氢黄酮(9)、松脂素(10)和熊果酸(11)。化合物3、9和10为首次从肾茶中分离得到。对化合物1~6进行活性测试,结果表明化合物3~5对乙酰胆碱酯酶具有一定的抑制活性。     

Flavonoids of geigeria

Chromatographic separation of the ethanol extract of Geigeria burkei resulted in the isolation and characterization of two known flavonoids, 5,7,3′,4′-tetrahydroxy-6-methoxyflavone and 5,7,4'-trihydroxy-6 methoxyflavone. ¹³CNMR data, as well as the respiratory inhibition and uncoupling of oxidative phosphorylation, is reported for the first time.     

Isoflavonoids from the roots of Erythrina poeppigiana

Five isoflavonoids, 7,4′-dihydroxy-2′-methoxy-8-(γ,γ-dimethylallyl)isoflav-3-ene, 4′-hydroxy-2′-methoxy-6″,6″-dimethylpyran[2″,3″:7,8]isoflav-3-ene, 5,7,4′-trihydroxy-2′-methoxy-5′-(γ,γ-dimethylallyl)isoflavanone, 5,4′-dihydroxy-7,2′-dimethoxy-5′-(γ,γ-dimethylallyl)isoflavanone and 3,9-dihydroxy-4-(γ,γ-dimethylallyl)pterocarpene as well as six known compounds were isolated from the roots of Erythrina poeppigiana. Their structures were established on the basis of spectroscopic evidence.     

Flavonoid aglycones from Xanthocephalum gymnospermoides var. gymnospermoides

Six known flavonoid aglycones and the newly described 5,7,4′-trihydroxy-3,3′,5′-trimethoxyflavone were isolated from Xanthocephalum gymnospermnoides var. gymnospermnoides.     

5-Methyl ether flavone glucosides from the leaves of Bruguiera gymnorrhiza

Two new 5-methyl ether flavone glucosides (7,4′,5′-trihydroxy-5,3′-dimethoxyflavone 7-O-β-D-glucopyranoside and 7,4′-dihydroxy-5-methoxyflavone 7-O-β-D-glucopyranoside) were isolated from the leaves of Thai mangrove Bruguiera gymnorrhiza together with 7,3′,4′,5′-tetrahydroxy-5-methoxyflavone, 7,4′,5′-trihydroxy-5,3′-dimethoxyflavone, luteolin 5-methyl ether 7-O-β-D-glucopyranoside, 7,4′-dihydroxy-5,3′-dimethoxyflavone 7-O-β-D-glucopyranoside, quercetin 3-O-β-D-glucopyranoside, rutin, kaempferol 3-O-rutinoside, myricetin 3-O-rutinoside and an aryl-tetralin lignan rhamnoside. The structure of a lignan rhamnoside was found to be related to racemiside, an isolated compound from Cotoneaster racemiflora, and also discussed. Structure determinations were based on analyses of physical and spectroscopic data including 1D- and 2D-NMR.