Halogenated secondary metabolites from Laurencia obtusa

A new sesquiterpene (1), and a halogenated C15 acetogenin (2), a stereoisomer of neoisoprelaurefucin were isolated from Laurencia obtusa. Four known compounds laurencienyne (3), rogiolenyne B (4), obtusenol (5), and (3E)-dactomelyne (6) were also isolated from this alga. Rogiolenyne B (4) and (3E)-dactomelyne (6) were found for the first from this species. The structures of these compounds were elucidated by spectroscopic methods. The unambiguous assignments of the 1H and 13C NMR spectral data of (5) and 13C NMR data of (6) were also reported for the first time.     

Triazoles and Other N‐Containing Metabolites from the Marine‐Derived Endophytic Fungus Penicillium chrysogenum EN‐118

Two new triazoles, chrysotriazoles A and B ( 1 and 2 , resp.), along with two known quinazolinones, 3 and 4 , two known 2‐(4‐hydroxyphenyl)acetamides, 5 and 6 , and two known N‐(4‐hydroxystyryl)formamides, 7 and 8 , were isolated and identified from the culture extract of Penicillium chrysogenum EN‐118, an endophytic fungus obtained from the marine brown alga Sargassum pallidium. The structures of the isolated compounds were elucidated by NMR‐spectroscopic analysis, and that of compound 1 was confirmed by X‐ray crystallographic analysis of its p‐bromobenzoate derivative. Compounds 4, 5 , and 7 showed moderate cytotoxicities against Du145, A‐549, and HeLa cell lines.     

Plastoquinones from Sargassum yezoense; chemical structures and effects on the activation of peroxisome proliferator-activated receptor gamma

Four new plastoquinones, together with two known compounds, sargahydroquinoic acid and sargaquinoic acid, were isolated from the brown alga, Sargassum yezoense collected from the eastern coast of Korea. The structures of these compounds were elucidated based on spectroscopic analyses including NMR and MS. Their structures designated as meroterphenol A (1), B (2), C (3) and D (4) were characterized by a 6-methyl-1,4-benzohydroquinone moiety with an oxygenated diterpenoic acid chain. Meroterphenols A-D showed potent activation effects on peroxisome proliferator-activated receptor gamma (PPARγ).     

A new naphthoquinoneimine derivative from the marine algal-derived endophytic fungus Aspergillus niger EN-13

Cultivation of an endophytic fungus Aspergillus niger EN-13 that was isolated from the inner tissue of the marine brown alga Colpomenia sinuosa resulted in the characterization of a new naphthoquinoneimine derivative,namely,5,7-dihydroxy-2-[1-(4- methoxy-6-oxo-6H-pyran-2-yl)-2-phenylethylamino]-[1,4]naphthoquinone.The structure of the new compound was established on the basis of various NMR spectroscopic analyses including 2D NMR techniques,EI-MS,and HR-ESI-MS.This compound displayed moderate antifungal activity.     

Asporyergosterol, a new steroid from an algicolous isolate of Aspergillus oryzae

Asporyergosterol (1), a new steroid with an E double bond between C-17 and C-20, was identified from the culture extracts of Aspergillus oryzae, an endophytic fungus isolated from the marine red alga Heterosiphonia japonica. Moreover, four known steroids including (22E,24R)-ergosta-4,6,8(14),22-tetraen-3-one (2), (22E,24R)-3beta-hydroxyergosta-5,8,22-trien-7-one (3), (22E,24R)-ergosta-7,22-dien-3beta,5alpha,6beta-triol (4), and (22E,24R)-5alpha,8alpha-epidioxyergosta-6,22-dien-3beta-ol (5) were isolated. Structures of these compounds were unambiguously established by spectroscopic techniques and by comparison with literature values. All the isolates exhibited low activity to modulate acetylcholinesterase (AChE).     

A new sesquiterpene from an endophytic Aspergillus versicolor strain

A new sesquiterpene, albican-1,14-diol (1), and seven known compounds, including sterigmatocystin (2), 3-hydroxy-5-(hydroxymethyl)-4-(4'-hydroxyphenoxy) pyrrolidin-2-one (3), (1H-indol-3-yl) oxoacetamide (4), indole-3-carboxylic acid (5), indole-3-acetic acid (6), indole-3-carboxaldehyde (7), and volemolide (8), were isolated from the cultures of Aspergillus versicolor, an endophytic fungus isolated from the marine green alga Codium fragile. The structure of 1 was elucidated by 1D, 2D NMR and mass spectroscopic techniques. The bioassay results showed that 1 possessed potent activity against brine shrimp, Escherichia coli, and Staphyloccocus aureus.     

New antifungal cholestane and aldehyde derivatives from the red alga Laurencia papillosa

The chloroform/methanol extract of the red alga, Laurencia papillosa, collected from the Red Sea in Saudi Arabia, was found to contain two cholestane derivatives: 3alpha, 6alpha-dihydroxy-5beta-cholestan-12-one (1) and the known, 6beta-hydroxycholest-4-en-3-one (2), which was isolated separately in a pure form for the first time. In addition to these compounds, a new aldehyde derivative, (E)-2-{(E) tridec-2-en-2-yl} heptadec-2-enal (3), was isolated. The structures of all compounds were established based on extensive spectroscopic (1D and 2D NMR, UV, IR) and mass spectrometric studies. All compounds, except 2, were tested for their antifungal activity. Significant activities were associated with 1 and 3 against Candida albicans, Aspergillus fumigatus, and A. flavus.     

Isolation of tetraprenyltoluquinols from the brown alga Sargassum thunbergii

Thunbergols A (4) and B (5), tetraprenyltoluquinols, along with three known compounds (1-3) have been isolated from the brown alga Sargassum thunbergii. The structures of these two new compounds were determined to be 9-(3,4-dihydro-2,8-dimethyl-6-hydroxy-2H-1-benzopyran-2-yl)-6-methyl-2-(4-methyl-3-pentenyl)-(2E,6E)-nonadienoic acid (4) and 10-(2,3-dihydro-5-hydroxy-7-methyl-1-benzofuran-2-yl)-10-hydroxy-6-methyl-2-(4-methyl-3-pentenyl)-(2E,6E)-undecadienoic acid (5), respectively, by combined spectroscopic methods. Both of them exhibited significant scavenging activities on radical and potently inhibited generation of ONOO(-) from morpholinosydnonimine (SIN-1).     

Studies on the constituents of the green alga <Emphasis Type="Italic">Ulva lactuca</Emphasis>

Phytochemical investigations on a marine green alga Ulva lactuca led to the isolation of two new compounds (E)-6-heptacosen-5-one (1) and (E)-6-octadecen-5-ol (2), along with four known compounds, (Z)-10-hexacosene (3), docosanoic acid (4), palmitic acid (5), and isofucosterol (6). Compounds 3 and 4 were isolated for the first time from this species. The structures of the compounds were deduced with the help of modern spectroscopic techniques.     

Benzodiazepine Alkaloids from Marine‐Derived Endophytic Fungus Aspergillus ochraceus

A new fungus‐derived benzodiazepine analogue, 2‐hydroxycircumdatin C ( 1 ), and a compound which has been isolated from a natural resource for the first time, but has been previously synthesized, namely (11aS)‐2,3‐dihydro‐7‐methoxy‐1H‐pyrrolo[2,1‐c][1,4]benzodiazepine‐5,11(10H,11aH)‐dione ( 2 ), along with five structurally related known alkaloids ( 3 – 7 ), were isolated from Aspergillus ochraceus, an endophytic fungus derived from the marine brown alga Sargassum kjellmanianum. Their structures were established on the basis of spectroscopic methods. The absolute configuration of 1 was determined through CD evidence. Compound 1 displayed significant DPPH radical‐scavenging activity with an IC₅₀ value of 9.9 μM , which is 8.9‐fold more potent than that of butylated hydroxytoluene (BHT), a well‐known synthetic positive control.     

Laurane-derived sesquiterpenes from the marine red alga Laurencia tristicha (Rhodomelaceae)

Two new stereoisomers of laurane-derived brominated sesquiterpenes, 4-bromolaur-11-en-1,10alpha-diol (1) and 4-bromolaur-11-en-1,10beta-diol (2), one new natural product, laur-11-en-1,10alpha-diol (3), together with 11 known compounds (4-14) were isolated and identified from the organic extract of the marine red alga Laurencia tristicha. Their structures and relative stereochemistry were established by analysis of mass and NMR spectroscopic techniques.     

Sarcophytolides G–L,New Biscembranoids from the Soft Coral Sarcophyton elegans

Six new biscembranoids, namely, sarcophytolides G–L ( 1 – 6 , resp.), together with six known analogs, were isolated from a marine soft coral Sarcophyton elegans. The structures of the new compounds were established on the basis of 1D‐ and 2D‐NMR (COSY, HSQC, HMBC, and NOESY) spectroscopic analysis together with the aid of MS, CD, and IR data. The unusual isobiscembranoid sarcophytolide G ( 1 ) was found for the first time in the genus Sarcophyton.     

A new isorhamnetin glycoside and other phenolic compounds from Callianthemum taipaicum

A new flavonol glycoside together with five known phenolic compounds were isolated from the whole herb of Callianthemum taipaicum. The compounds were identified as isorhamnetin-3-O-α-L-arabinoside-7-O-β-D-glucoside (1), isorhamnetin-3-O-β-D-glucoside (2), dibutyl phthalate (3), (+)-1-hydroxylpinoresinol-4'-β-D-glucoside (4), pinoresinol-4'-O-β-D-glucoside (5) and 2-phenylethyl-β-primeveroside (6). Compound 1 was identified as a new flavonol glycoside. The compound 6 was isolated for the first time as natural product. All compounds were isolated for the first time from the Callianthemum genus. Furthermore, the 2D-NMR data of the four known compounds 2-5 are given for the first time in this paper. All the structures were identified on the basis of detailed spectral analysis. The compounds 1 and 4 exhibited certain antifungal activity.     

Two new cinnamic acid esters from Marine brown alga Spatoglossum variabile

Two new natural products, n-butyl and isopropyl 3,5-dimethoxy-4-hydroxycinnamate were isolated from Spatoglossum variabile. Three known compounds, methyl 3,4,5-trihydroxybenzoate, 2-deoxyinosine and 9-beta-(D-ribofuranosyl)adenine were isolated for the first time from the methanolic extracts of this alga. The structure elucidations of the new compounds were carried out with the help of modern spectroscopic techniques.     

Halogenated chamigrane sesquiterpenes from Laurencia okamurae

Three new halogenated chamigrane sesquiterpenes, laurokamin A (1), laurokamin B (2), and laurokamin C (3), and four known halogenated chamigrane sesquiterpenes, 10‐bromo‐α‐chamigrene (4), 10‐bromo‐β‐chamigrene (5), 2,10‐dibromo‐3‐chloro‐β‐chamigrene (6), and obtusane (7), were isolated from the marine red alga Laurencia okamurae collected from the coast of Rongcheng, China. The structures of these compounds were unambiguously identified by one‐ and two‐dimensional NMR and mass spectroscopic methods. The antimicrobial activity of compounds 1–3 was evaluated. Copyright © 2012 John Wiley & Sons, Ltd.     

Sesquiterpenes and Other Metabolites from the Marine Red Alga Laurencia composita (Rhodomelaceae)

Two new halogenated sesquiterpenes, (8β)‐10‐bromo‐3‐chloro‐2,7‐epoxychamigr‐9‐en‐8‐ol ( 1 ) and 2‐bromo‐3‐chlorobisabola‐7(14),11‐diene‐6,10‐diol ( 3 ), and one new phytol‐derived diterpene, 2,3‐epoxyphytyl acetate ( 4 ), along with cis‐ and trans‐1‐methylcyclohexane‐1,4‐diol ( 5 and 6 ) which were isolated from a natural source for the first time but have been previously synthesized, were isolated from the marine red alga Laurencia composita and characterized. In addition, a known sesquiterpene, pacifenediol ( 2 ), and the known furanone derivative 7 were also identified. Their structures were established by NMR and mass spectroscopic methods.     

(1)H and (13)C NMR assignments for five anthraquinones from the mangrove endophytic fungus Halorosellinia sp. (No. 1403)

We report the unambiguous assignments of the (1)H and (13)C NMR spectra of two new natural products, namely, 1,4,5,6,7,9-hexahydroxy-2-methoxy-7-methyl-5beta,9beta,8abeta, 6alpha,10aalpha-hexahydroanthracen-10 (10aH)-one (1) and 1,4,6-trihydroxy-2-methoxy-7-methylanthracene-9, 10-dione (2), together with three known anthraquinones. These compounds were all isolated from the marine endophytic fungus No. 1403 collected from the South China Sea. Compounds 3 and 4 were isolated from the marine fungus for the first time. The structures were elucidated by the spectroscopic methods 1D and 2D NMR including COSY, HMQC, HMBC and NOE, and HREIMS. In our cytotoxicity assays, compound 5 showed cytotoxicity toward KB and KBv-200 cells with IC(50) of 1.40 and 2.58 microg/ml, respectively. In addition, the plausible biogenic relationship of compounds 1, 2, 3 and 4 is discussed.     

Highly Oxygenated Triterpenoids from the Marine Red Alga Laurencia mariannensis (Rhodomelaceae)

Two new and one known squalenoid‐derived triterpenoids, namely, laurenmariannol ( 1 ) and (21α)‐21‐hydroxythyrsiferol ( 2 ), and the known thyrsiferol ( 3 ) were isolated and identified from the marine red alga Laurencia mariannensis, which was collected off the coast of Hainan and Weizhou Islands of China. The structures of these compounds were established by means of spectroscopic analyses, as well as by comparison with literature data. Compounds 1 and 2 displayed significant cytotoxic activity against P‐388 tumor cells with IC₅₀ values of 0.6 and 6.6 μg/ml, respectively.     

Aristolane Sesquiterpenes and Highly Brominated Indoles from the Marine Red Alga Laurencia similis (Rhodomelaceae)

Three new polybrominated 1H‐indoles, compounds 1 – 3 , and three new aristolane sesquiterpenes, compounds 4 – 6 , were isolated from the marine red alga Laurencia similis, together with seven known natural products. Their structures were elucidated on the basis of detailed spectroscopic and mass‐spectrometric analyses, as well as by comparison with literature data.     

A new aliphatic ester of hydroxysalicylic acid from fermented Carica papaya L. preparation with a potential hair growth stimulating activity

Abstract

An aliphatic ester of hydroxysalicylic acid (6), reported for the first time from a natural source in addition to five known compounds were isolated from the fermented Carica papaya L. preparation, a commercialized functional food. The known compounds were identified as 5-hydroxymethylfurfuraldehyde (1), trans-caffeic acid (2), butyl 4-hydroxybenzoate (butylparaben) (3), lycopene (4), benzyl isothiocyanate (5). Compounds 1 and 3 were reported for the first time from Papaya fruits through this study. The new compound showed a moderate antioxidant activity and a potent hair growth stimulating activity in vitro.