Four new bromotryptamine derivatives from the marine bryozoan Flustra foliacea

Ten brominated alkaloids, 6-bromo-2-(1,1-dimethyl-2-propenyl)-1H-indole-3-carbaldehyde (1), N-(2-[6-bromo-2-(1,1-dimethyl-2-propenyl)-1H-indol-3-yl]ethyl)-N-methylmethanesulfonamide (2), deformylflustrabromine (3), flustrabromine (4), (3aR,8aS)-6-bromo-3a-[(2E)-3,7-dimethyl-2,6-octadienyl]-1,2,3,3a,8,8a-hexahydropyrrolo[2,3-b]-indol-7-ol (5), flustramine C (6), dihydroflustramine C (7), flustramine A (8), flustramine D (9), and flustraminol A (10), and the diterpene 4,6-bis(4-methylpent-3-en-1-yl)-6-methylcyclohexa-1,3-diene-carbaldehyde (11) were isolated from the dichloromethane extract of the North Sea bryozoan Flustra foliacea. Of the 10, four (1, 2, 3, and 5) represent new natural products. The structures of all isolates were elucidated by interpretation of their spectroscopic data (NMR, MS, UV, and IR). For compound 4 complete (13)C NMR data are reported for the first time. Compounds 3 and 6-8 were tested on voltage-activated potassium and sodium channels. Flustramine A (8) shows an unspecific blocking activity on Kv1.4 potassium-mediated currents.     

Chiral dihydroxylation of acronycine: absolute configuration of natural cis-1,2-dihydroxy-1,2-dihydroacronycine and cytotoxicity of (1R,2R)- and (1S,2S)-1,2-diacetoxy-1,2-dihydroacronycine

Sharpless asymmetric dihydroxylation of acronycine (1) gave (1R, 2R)-1,2-dihydroxy-1,2-dihydroacronycine (2) and (1S,2S)-1, 2-dihydroxy-1,2-dihydroacronycine (3), which allowed determination of the absolute configuration of natural cis-1,2-dihydroxy-1, 2-dihydroacronycine as 1R,2R. The cis isomer had been previously isolated from various Sarcomelicope species. Benzylic reduction of isomers 2 and 3 gave the alcohols 4 (2R) and 5 (2S), respectively. Acetylation of 2 and 3 afforded the corresponding esters 6 and 7. No significant difference of cytotoxicity was observed between these (1R,2R)- and (1S,2S)-enantiomers and the recently described, highly active racemic cis-1,2-diacetoxy-1,2-dihydroacronycine, when tested against L-1210 cells in vitro.     

Laurendecumallenes A-B and laurendecumenynes A-B, halogenated nonterpenoid C(15)-acetogenins from the marine red alga Laurencia decumbens

Four new halogenated nonterpenoid C(15)-acetogenins, 4:7,6:13-bisepoxy-9,10-diol-1,12-dibromopentadeca-1,2-diene (1, laurendecumallene A), 4:7,6:12-bisepoxy-9,10-diol-1,13-dibromopentadeca-1,2-diene (2, laurendecumallene B), (3Z)-6:10,7:13-bisepoxy-12-bromo-9-hydroperoxylpentadeca-3-en-1-yne (3, laurendecumenyne A), and (3Z)-6:10,9:13-bisepoxy-12-bromo-7-chloropentadeca-3-en-1-yne (4, laurendecumenyne B), together with one known halogenated C(15)-acetogenin elatenyne (5) were isolated and identified from the organic extract of the marine red alga Laurencia decumbens. Their structures and relative stereochemistry were established by means of spectroscopic analysis including UV, IR, high-resolution electrospray ionization mass spectrometry (HRESIMS), and 1D and 2D NMR techniques. All these metabolites were submitted for the cytotoxic assay against tumor cell line A549 (human lung adenocarcinoma), but all of them were found inactive (IC(50) > 10 microg/mL).     

Nitrogen-containing compounds from Salvia miltiorrhiza

Five new N-containing compounds, neosalvianen (1), salvianen (2), salvianan (3), salviadione (4), and 5-(methoxymethyl)-1H-pyrrole-2-carbaldehyde (5), were isolated from Salvia miltiorrhiza. Their structures were mainly established by spectroscopic methods. Neosalvianen (1) and its analogues (6a, 6b) were synthesized for spectroscopic data comparison. Compounds 1, 2, 4, and 6a were evaluated for their cytotoxic activities against selected cancer cell lines. Among these components, salvianen (2) exhibited the most potent cytotoxicity with a CD50 range of 30.4-39.5 microM against HeLa (cervical epitheloid carcinoma), HepG2 (hepatocellular carcinoma), and OVCAR-3 (ovarian adenocarcinoma) cell lines in a dose-dependent manner. The cytotoxicities of the tested compounds were not specific and showed similar activities to the selected cancer cell lines.     

New anthracene derivatives from Coussarea macrophylla

Five new naturally occurring anthracene derivatives, 1,4,10-trimethoxyanthracene-2-carbaldehyde (1), (1,4,10-trimethoxy-2-anthracen-2-yl)methanol (2), 1,4,8,10-tetramethoxyanthracene-2-carbaldehyde (3), 1,4,10-trimethoxyanthracene-2-carboxylic acid (4), and 1,3-dimethoxy-2-methoxymethylanthraquinone (5), were isolated from Coussarea macrophylla along with three known compounds, 3-hydroxy-1-methoxy-2-methoxymethylanthraquinone (6), scopoletin, and 3-epi-pomolic acid. The structures of 1-5 were determined on the basis of analysis of their spectroscopic data and by total synthesis.     

Brominated sesquiterpenes from the red alga Laurencia obtusa

Four new sesquiterpenes, (8R)-8-bromo-10-epi-beta-snyderol (1), (8S)-8-bromo-beta-snyderol (2), 5-bromo-3-(3'-hydroxy-3'-methylpent-4'-enylidene)-2,4,4-trimethylcyclohexanone (3), and the epoxide 4, have been isolated from the chloroform-methanol extract of Laurencia obtusa, together with the three known compounds alpha-snyderol (5), alpha-snyderol acetate (6), and stigmasterol. The structures of the isolated compounds were elucidated through spectroscopic analyses. Compound 1 showed antimalarial activity, with IC(50) values of 2700 and 4000 ng/mL against the D6 and W2 clones of Plasmodium falciparum, respectively.     

Bromophenols coupled with nucleoside bases and brominated tetrahydroisoquinolines from the red alga Rhodomela confervoides

Three new bromophenols C-N coupled with nucleoside base derivatives (1-3) and three new brominated 1,2,3,4-tetrahydroisoquinolines (5-7), together with a new brominated tyrosine derivative (4), have been isolated from polar fractions of an ethanolic extract of the red alga Rhodomela confervoides. By spectroscopic and chemical methods including HRMS and 2D NMR data, their structures were determined as 7-[3-bromo-2-(2,3-dibromo-4,5-dihydroxybenzyl)-4,5-dihydroxybenzyl]-3,7-dihydro-1H-purine-2,6-dione (1), 7-(2,3-dibromo-4,5-dihydroxybenzyl)-3,7-dihydro-1H-purine-2,6-dione (2), 9-[3-bromo-2-(2,3-dibromo-4,5-dihydroxybenzyl)-4,5-dihydroxybenzyl]adenine (3), (-)-8S-(3-bromo-5-hydroxy-4-methoxy)phenylalanine (4), (-)-3S-8-bromo-6-hydroxy-7-methoxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (5), methyl (-)-3S-8-bromo-6-hydroxy-7-methoxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylate (6), and methyl (-)-3S-6-bromo-8-hydroxy-7-methoxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylate (7). Compounds 5-7 were semisynthesized by using 4 as the starting material.     

New phenolic constituents from Smilax bracteata

From the methanol extract of Smilax bracteata rhizomes, six new phenolic compounds, (2S,3S)-5-O-beta-D-glucopyranosyloxy-6-methyl-3'-methoxy-3,7,3'-trihydroxyflavan (1), (2S,3S)-5-O-beta-D-glucopyranosyloxy-6-methyl-4'-methoxy-3,7,4'-trihydroxyflavan (2), 3beta-(3',5'-dihydroxyphenyl)-2alpha-(4' '-hydroxyphenyl)dihydrobenzofuran-5-carbaldehyde (3), (1-p-O-coumaroyl-6-O-feruroyl)-beta-D-fructofuranosyl-alpha-D-glucopyranoside (4), (1-p-O-coumaroyl-3,6-di-O-feruroyl)-beta-D-fructofuranosyl-alpha-D-glucopyranoside (5), and (6-O-feruroyl)-beta-D-fructofuranosyl-(6-O-acetyl)-alpha-D-glucopyranoside (6) were isolated together with five known compounds. Their structures were established by spectral data interpretation.     

Bromophenol derivatives from the red alga Rhodomela confervoides

Eight new bromophenol derivatives, 2,3-dibromo-4,5-dihydroxybenzyl methyl sulfoxide (1), 4-(2,3-dibromo-4,5-dihydroxyphenyl)-3-butene-2-one (2), 2-(3-bromo-5-hydroxy-4-methoxyphenyl)-3-(2,3-dibromo-4,5-dihydroxyphenyl)propionic acid (3), 2-(3-bromo-5-hydroxy-4-methoxyphenyl)-3-(2,3-dibromo-4,5-dihydroxyphenyl)propionic acid methyl ester (4), 2-phenyl-3-(2,3-dibromo-4,5-dihydroxyphenyl)propionic acid (5), 4'-methoxy-2',3',3'-tribromo-4',5',5'-trihydroxydiphenylacetic acid (6), and 3-bromo-5-hydroxy-4-methoxyphenylacetic acid (7) and its methyl ester (8), together with a known bromophenol, 3-bromo-5-hydroxy-4-methoxybenzoic acid (9), were isolated from the red alga Rhodomela confervoides. Their structures were elucidated by spectroscopic methods including IR, EIMS, FABMS, ESIMS, HRFABMS, HRESIMS, 1D and 2D NMR, and single-crystal X-ray structure analysis. Compounds 1-4, 8, and 9 were found inactive against several human cancer cell lines and microorganisms.     

蜘蛛香炮制品的化学成分和抗炎活性研究

目的 研究蜘蛛香炮制品的化学成分及其抗炎活性。方法 采用正相硅胶柱色谱、羟丙基葡聚糖凝胶(Sephadex LH-20)、ODS和高效液相色谱(HPLC)等多种分离材料和方法进行分离纯化,通过理化性质及波谱数据鉴定化合物结构,采用脂多糖(LPS)诱导的RAW264.7细胞体外炎症模型,以总一氧化氮合成酶抑制剂(L-NMMA)作为阳性对照,对化合物进行体外抗炎活性评价。结果 从蜘蛛香炮制品的乙酸乙酯相共分离鉴定了25个化合物,分别为(3S,4R,5S,7S,8S,9S)-3,8-环氧-7-羟基-4,8-二甲基全氢环戊基[c]吡喃(1)、(3S,4S,5S,7S,8S,9S)-3,8-环氧-7-羟基-4,8-二甲基全氢环戊基[c]吡喃(2)、去酰基缬草醛(3)、缬草醛(4)、8-羟基-7′-表松脂醇(5)、(+)-表松脂醇(6)、青刺尖木脂醇(7)、 (7R,8S,7′R,8′S)-5-甲氧基青刺尖木脂醇(8)、(-)-松脂醇(9)、绿原酸(10)、橙皮素(11)、3,8-二羟基-2-甲基色原酮(12)、penicisochroman J(13)、2,5-二(4-羟基-3-甲氧基苯基)-1,4-二烷(14)、4,4′-二羟基-3,3′-二甲氧基-反式-1,2-二苯乙烯(15)、对苯二酚(16)、4-羟基-3-甲氧基苯甲醛(17)、乙酰香草酮(18)、4-羟基-3-甲氧基桂皮醛(19)、2,3-二羟基-1-甲氧基苯(20)、5-羟甲基-2-呋喃甲醛(21)、5-乙酰糠醇(22)、5-[(5-(hydroxymethyl)furan-2-yl)methoxymethoxymethyl]furan-2-carbaldehyde(23)、5-({5-[(5-(hydroxy methyl)furan-2-yl)methoxy(methoxymethyl)]-furan-2-yl} methoxy(methoxymethyl)) furan-2-carbaldehyde(24)和6-羟基-2H-吡喃-3-醛(25)。其中,化合物3,15,16和19均能够显著抑制RAW264.7细胞中脂多糖诱导的一氧化氮生成,且呈显著的剂量依赖性,表现出潜在的抗炎活性。结论 炮制后的蜘蛛香化合物结构类型涉及环烯醚萜及其降解产物、苯丙素、黄酮、色原酮、芳香衍生物和糠醛衍生物等。在炮制过程中,主要是环烯醚萜和单糖的结构发生了变化;化合物 5、6、9~25均为首次从蜘蛛香中分离得到,其中,化合物3,15,16和19具有抗炎活性,半数抑制浓度(IC₅₀)值分别为29.04、10.77、6.37和10.98 μmol·L^-1。     

Bromophenols from the red alga Rhodomela confervoides

Six new bromophenols, 3-bromo-4,5-bis(2,3-dibromo-4,5-dihydroxybenzyl)pyrocatechol (1), 2,2',3-tribromo-3',4,4',5-tetrahydroxy-6'-hydroxymethyldiphenylmethane (2), 2,2',3-tribromo-3',4,4',5-tetrahydroxy-6'-ethyloxymethyldiphenylmethane (3), (+/-)-2-methyl-3-(2,3-dibromo-4,5-dihydroxyphenyl)propylaldehyde (4), (+/-)-2-methyl-3-(2,3-dibromo-4,5-dihydroxyphenyl)propylaldehyde dimethyl acetal (5), and 3-bromo-4,5-dihydroxybenzoic acid methyl ester (6), together with eight known bromophenols, 3-bromo-4,5-dihydroxybenzaldehyde (7), 2,3-dibromo-4,5-dihydroxybenzyl alcohol (lanosol, 8), 2,3-dibromo-4,5-dihydroxybenzyl methyl ether (9), 2,3-dibromo-4,5-dihydroxybenzyl ethyl ether (10), 2,3-dibromo-4,5-dihydroxybenzylaldehyde (11), bis(2,3-dibromo-4,5-dihydroxybenzyl) ether (12), 3-bromo-4-(2,3-dibromo-4,5-dihydroxybenzyl)-5-methoxymethylpyrocatechol (13), and 2,2',3,3'-tetrabromo-4,4',5,5'-tetrahydroxydiphenyl methane (14), were isolated from the red alga Rhodomela confervoides. Their structures were elucidated by chemical and spectroscopic methods including IR, HRFABMS, and 1D and 2D NMR techniques.     

半夏的化学成分研究

 目的研究半夏的化学成分。方法采用硅胶柱及SephadaxLH-20凝胶柱色谱法,运用波谱方法确定结构。结果从半夏中分离得到15个化合物,分别为大黄酚(1),丁二酸(2),正十六碳酸-1-甘油酯(3),soyacerebrosideI(4),octadeca-9,12-dienoicacidethylester(5),monogalactosyldiacyglycerol(6),soyacerebrosideII(7),3-O-(6′-O-棕榈酰基-β-D-吡喃葡萄糖基)豆甾-5-烯(8),对二羟基苯酚(9),1,6:3,4-dianhydro-β-D-allosep(10),1,6:2,3-dianhydro-β-D-allosep(11),5-羟甲基糠醛(12),邻二羟基苯酚(13)及β-谷甾醇(14),胡萝卜苷(15)。结论化合物1,3,5,6,811,13均为首次从半夏中分离得到。     

Investigation of brominated tryptophan alkaloids from two thorectidae sponges: Thorectandra and Smenospongia

Chemical investigation of an NCI-DTP collection of Thorectandra sp. and a UCSC collection of Smenospongia sp. yielded six new brominated tryptophan derivatives: 6-bromo-1'-hydroxy-1',8-dihydroaplysinopsin (4), 6-bromo-1'-methoxy-1',8-dihydroaplysinopsin (5), 6-bromo-1'-ethoxy-1',8-dihydroaplysinopsin (6), (-)-5-bromo-N,N-dimethyltryptophan (7), (+)-5-bromohypaphorine (8), and 6-bromo-1H-indole-3-carboxylic acid methyl ester (11). Additionally, the known compounds aplysinopsin (1), 1',8-dihydroaplysinopsin (2), 6-bromo-1',8-dihydroaplysinopsin (3), (1H-indole-3-yl)acetic acid (9), and (6-bromo-1H-indol-3-yl)acetic acid methyl ester (10) were also encountered. The structures of 4-8 and 11 were confirmed on the basis of analysis of (1)H and (13)C (1D and 2D) NMR data as well as comparison to known compounds. Compounds 1, 3-8, 10, and 11 were found to inhibit the growth of Staphylococcus epidermidis with either weak or moderate MICs.     

Two diphenylpropan-1,2-diol syringates from the roots of Erythrina variegata

Two new diphenylpropan-1,2-diols, eryvarinols A (1) and B (2), were isolated from the roots of Erythrina variegata. Their structures were elucidated as 1-(4-hydroxy-2-methoxyphenyl)-2-(4-hydroxy-3,5-dimethoxybenzoyloxy)-3-(4-hydroxyphenyl)propan-1-ol (1) and its 3"-prenyl derivative (2) on the basis of spectroscopic and chemical evidence. Both these compounds are unusual diphenylpropan-1,2-diols with a syringyl group.     

Brominated labdane-type diterpenoids from an Okinawan Laurencia sp

From an unidentified species of Laurencia collected from Okinawan waters two novel brominated metabolites, 1 and 2, along with known halogenated compounds, 2,10-dibromo-3-chloro-alpha-chamigrene (3) and microcladallene A (4), were isolated and identified. The structures of these new compounds were established as ent-labdane-type bromoditerpenes, (1S,3R,5S,6S,8S,9S,10R,13R)-1-acetoxy-3-bromo-6-hydroxy-8,13-epoxy-labd-14-ene (1) and (3R,5S,6S,8S,9S,10R,13R)-3-bromo-6-hydroxy-8,13-epoxylabd-14-en-1-one (2), by interpretation of their spectroscopic data as well as by X-ray crystallographic analysis.     

Bromophenols from the marine red alga Polysiphonia urceolata with DPPH radical scavenging activity

Three new (1-3) and three known (4-6) bromophenols were isolated and identified from the marine red alga Polysiphonia urceolata. On the basis of extensive analysis of spectroscopic data, the structures of these compounds were determined to be 7-bromo-9,10-dihydrophenanthrene-2,3,5,6-tetraol (1), 4,7-dibromo-9,10-dihydrophenanthrene-2,3,5,6-tetraol (2), 1,8-dibromo-5,7-dihydrodibenzo[ c,e]oxepine-2,3,9,10-tetraol (3), urceolatol (4), 3-bromo-4,5-dihydroxybenzaldehyde (5), and 3,5-dibromo-4-hydroxybenzaldehyde (6). Each of the isolated compounds was evaluated for alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) radical scavenging activity, and all were found to be potent, with IC50 values ranging from 6.1 to 35.8 microM, compared to the positive control, butylated hydroxytoluene (BHT), with an IC50 of 83.8 microM.     

Bioactive secondary metabolites from Boesenbergia pandurata of Myanmar and their preferential cytotoxicity against human pancreatic cancer PANC-1 cell line in nutrient-deprived medium

The chloroform extract of rhizomes of Boesenbergia pandurata demonstrated marked preferential cytotoxicity against human pancreatic PANC-1 cancer cells in nutrient-deprived medium. Bioactivity-directed investigation of this extract yielded four new secondary metabolites, geranyl-2,4-dihydroxy-6-phenethylbenzoate ( 1), 2',4'-dihydroxy-3'-(1'-geranyl)-6'-methoxychalcone ( 2), (1' R,2' S,6' R)-2-hydroxyisopanduratin A ( 3), and (2 R)-8-geranylpinostrobin ( 4), and twenty known compounds ( 5- 24). Among the known compounds, (2 S)-6-geranylpinostrobin ( 5), (+/-)-6-methoxypanduratin A ( 6), and (2 S)-7,8-dihydro-5-hydroxy-2-methyl-2-(4'-methyl-3'-pentenyl)-8-phenyl-2 H,6 H-benzo[1,2- b:5,4- b']dipyran-6-one ( 7) were isolated for the first time from a natural source. The structures of these compounds were elucidated using extensive spectroscopic techniques including CD measurements. All the isolated compounds showed varying degrees of in vitro preferential cytotoxicity against PANC-1 cells. Nicolaioidesin B ( 11) and panduratin A ( 17) were most potent, each showing a PC 100 at 2.5 microM.     

Bromophenols coupled with methyl gamma-ureidobutyrate and bromophenol sulfates from the red alga Rhodomela confervoides

Four new bromophenols C-N coupled with methyl gamma-ureidobutyrate (1-4), a phenylethanol bromophenol (5), and three phenylethanol sulfate bromophenols (6-8) have been isolated from polar fractions of an ethanolic extract of the red alga Rhodomela confervoides. On the basis of spectroscopic evidence including HRMS and 2D NMR data, the structures of the new compounds were determined as methyl N'-(2,3-dibromo-4,5-dihydroxybenzyl)-gamma-ureidobutyrate (1), methyl N,N'-bis(2,3-dibromo-4,5-dihydroxybenzyl)-gamma-ureidobutyrate (2), methyl N'-[3-bromo-2-(2,3-dibromo-4,5-dihydroxybenzyl)-4,5-dihydroxybenzyl]-gamma-ureidobutyrate (3), methyl N'-(2,3-dibromo-4,5-dihydroxybenzyl)-N'-[3-bromo-2-(2,3-dibromo-4,5-dihydroxybenzyl)-4,5-dihydroxybenzyl]-gamma-ureidobutyrate (4), 2,3-dibromo-4,5-dihydroxyphenylethanol (5), 2,3-dibromo-4,5-dihydroxyphenylethanol sulfate (6), 3-bromo-4,5-dihydroxyphenylethanol sulfate (7), and 3-bromo-2-(2,3-dibromo-4,5-dihydroxybenzyl)-4,5-dihydroxyphenylethanol sulfate (8). The cytotoxicity of all compounds was evaluated against several human cancer cell lines including human colon cancer (HCT-8), hepatoma (Bel7402), stomach cancer (BGC-823), lung adenocarcinoma (A549), and human ovarian cancer (A2780). Among them, the phenylethanol and the phenylethanol sulfate bromophenols (5-8) showed moderate cytotoxicity against all tested cell lines.     

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??OBJECTIVE To study the chemical components of the aqueous extract of Solanum lyratum. METHODS The compounds were isolated and purified by column chromatography and their structures were elucidated by spectroscopic methods. RESULTS Nine phenylpropanoids were obtained from aqueous extracts of Solanum lyratum. The structures were determined as chlorogenic acid(1), crptochlorogenic acid(2), neochlorogenic acid(3), erythro-1,2-bis-(4-hydroxy-3- methoxyphenyl)-1,3-propanediol(4), threo-1,2-bis-(4-hydroxy-3-methoxyphenyl)-1,3-propanediol(5), erythro-2,3-bis-(4-hydroxy-3-methoxyphenyl)-3-methoxypropanol(6), threo-2,3-bis-(4-hydroxy-3- methoxyphenyl)-3-methoxypropanol(7), syringaresinol(8), and liriodendrin(9). CONCLUSION Compounds 2-9 are isolated from Solanum lyratum for the first time.     

Dibenzyl bromophenols with diverse dimerization patterns from the brown alga Leathesia nana

Six novel dibenzyl bromophenols (1-6) with different dimerization patterns and two propyl bromophenol derivatives (7 and 8), together with 11 known bromophenol derivatives, were isolated from the ethanolic extract of the brown alga Leathesia nana. On the basis of spectroscopic methods the structures of the new compounds were determined as 5,6'-diethyloxymethyl-3,4,2'-tribromo-2,3',4'-trihydroxydiphenyl ether (1), 2-(2,3-dibromo-4,5-dihydroxybenzyl)-3,5-dihydroxy-4-methoxybenzyl alcohol (2), 6-(2,3-dibromo-4,5-dihydroxybenzyl)-2,3-dibromo-4,5-dihydroxy benzyl methyl ether (3), 9,10-dihydro-9,10-dimethoxy-3,4,7,8-tetrabromo-1,2,5,6-tetrahydroxyanthracene (4), (+)-3-(2,3-dibromo-4,5-dihydroxyphenyl)-4-bromo-5,6-dihydroxy-1,3-dihydroisobenzofuran (5), rel-(4aS,10aR)-(+/-)-6,7-dibromo-4a-hydroxy-3,8-dihydroxymethyl-10a-methoxy-1,4,4a,10a-tetrahydrodibenzo[b,e][1,4]dioxin-1-one (6), (E)-2-methyl-3-(2,3-dibromo-4,5-dihydroxyphenyl)propenal (7), and 2-methyl-3-(2,3-dibromo-4,5-dihydroxyphenyl)-1-propanol (8). Some compounds including 3 showed in vitro selective cytotoxicity against several human cancer cell lines. This is the first brown alga to be reported containing bromophenols.