Carandinol: First isohopane triterpene from the leaves of Carissa carandas L. and its cytotoxicity against cancer cell lines

A new triterpene carandinol (1) was isolated from the leaves of Carissa carandas L., along with five known compounds, betulinic acid (2), β-sitosterol-3-O-β-d-glucopyranoside (3), oleanolic acid (4), ursolic acid (5) and 4-hydroxybenzoic acid (6). The structure of compound 1 was deduced as 3β,21α-dihydroxyisohopane by exhaustive spectroscopic analyses. The known compounds 2–6 were identified by comparison with the reported spectral data. Compound 1 was evaluated for cytotoxicity, immunomodulatory, antiglycation, antioxidant and enzyme inhibition activity. It exhibited significant in vitro cytotoxicity to every cell line tested (HeLa, PC-3 and 3T3) and was relatively more toxic to human cervical cancer (HeLa) cell line. This is the first report of the isolation of an isohopane triterpene from the genus Carissa. Carandinol also represents the first example of a cytotoxic isohopane.     

A new polyacetylenic fatty acid and other secondary metabolites from the Chinese green alga Caulerpa racemosa (Caulerpaceae) and their chemotaxonomic significance

A new polyacetylenic fatty acid, (8E,12Z,15Z)-10-hydroxy-8,12,15-octadecatrien-4,6-diynoic acid (1), together with five known metabolites, including two linear diterpenes (3 and 4) and three sterols (5–7), has been isolated from the Chinese green alga Caulerpa racemosa. Its structure was determined on the basis of extensive spectroscopic analysis. Compound 1 represents the first example of polyacetylenic lipids from marine algae up to now, while compound 4 is characterized for the first time in the Caulerpaceae. Furthermore, the chemotaxonomic significance of these compounds was also summarized.     

Polyphenols and diterpenoids from Plectranthus forsteri ‘Marginatus’

Polyphenols caffeic acid (1), rosmarinic acid (2), nepetoidins A and B (3) and diterpenoids 7β,6β-dihydroxyroyleanone (4) and 7β-acetoxy-6β-hydroxyroyleanone (5) were identified in the methanolic extract of Plectranthus forsteri ‘Marginatus’ Benth. 6,7-dehydroroyleanone (6) was isolated from essential oil. The structure was identified using spectroscopic analysis and comparing it to standards.     

Phenolic compounds and ecdysteroids of Diplazium esculentum (Retz.) Sw. (Athyriaceae) from Japan and their chemotaxonomic significance

Four phenolic compounds, (2R)-3-(4′-hydroxyphenyl) lactic acid, trans-cinnamic acid (2), protocatechuic acid (3) and rutin (4), and three ecdysteroids, amarasterone A1 (5), makisterone C (6) and ponastrone A (7) were isolated and identified from the young fronds of Diplazium esculentum (Retz.) Sw. (Athyriaceae). The structures of these compounds were elucidated on the basis of NMR spectral data and comparison with literature values. Compounds 1, 2 and 5–7 were isolated for the first time from title plant. Their structure elucidation and chemotaxonomic significance are explained in detail.     

Chemical constituents from Alnus mandshurica (Callier) Hand.-Mazz. and their chemotaxonomic significance

A new phenol compound, (9S)-9-hydroxy-9-[(2-hydroxyphenyl)methoxy]-nonanoic acid methyl ester (1) was isolated from the stem bark of Alnus mandshurica (Callier) Hand.-Mazz., along with eight known compounds (2–9). The structure of compound 1 was determined by spectral analyses, including HR-ESI-MS, 1D and 2D NMR (COSY, HMQC and HMBC) experiments. All the isolated compounds were reported for first time from A. mandshurica. Furthermore, compounds 3–9 were found in the family Betulaceae for the first time.     

Kakeromamide A,a new cyclic pentapeptide inducing astrocyte differentiation isolated from the marine cyanobacterium Moorea bouillonii

Kakeromamide A (1), a new cyclic pentapeptide encompassing a thiazole ring moiety and a β-amino acid, was isolated from the marine cyanobacterium Moorea bouillonii. Its structure was elucidated by the spectral analysis and the modified Marfey’s method. Compound 1 induced differentiation of neural stem cells into astrocytes at the concentration of 10?µM.     

Isolation,structure elucidation and cytotoxic evaluation of endiandrin B from the Australian rainforest plant Endiandra anthropophagorum

Chemical investigations of the DCM extract from the roots of Endiandra anthropophagorum resulted in the isolation of a new cyclobutane lignan endiandrin B (1), together with the known natural products, endiandrin A (2), and (?)-dihydroguaiaretic acid (3). The structure of 1 was determined by extensive spectroscopic analyses, and confirmed by single crystal X-ray crystallography. Methylation of 1 using diazomethane afforded the previously reported natural product, cinbalansan (4). All compounds were evaluated for their cytotoxicity towards human lung carcinoma cells (A549) using high-content screening. (?)-Dihydroguaiaretic acid (3) was found to be the most potent cytotoxin against the A549 lung carcinoma cell line, with an IC₅₀ value of 7.49 μM.     

Iridoids,monoterpenoid glucoindole alkaloids and flavonoids from Vinca major

A new secoiridoid glucoside, vinmajoroside (1), was isolated from the leaves of Vinca major L. along with 11 known compounds belonging to the secoiridoid ((7α)-7-O-methylmorroniside, 2), iridoid (loganin, loganic acid and 7-O-p-coumaroylloganin), monoterpenoid glucoindole alkaloid (5 (S)-5-carboxyvincoside and strictosamide), flavonoid (rutin, kaempferol 3-O-rutinoside and robinin), lignan (syringaresinol 4-O-β-glucopyranoside) and phenolic acid (chlorogenic acid) groups. The structure elucidation of the isolates was accomplished by extensive 1D and 2D-NMR experiments as well as ESI-MS. Secoiridoids and lignan were encountered for the first time in the genus Vinca.     

A new sesquiterpenoid from Sclerorhachis platyrachis (Boiss.) Podlech ex Rech.f

A new eudesmane-type sesquiterpenoid together with two known flavonoids were isolated from the chloroform extract of the aerial part of Sclerorhachis platyrachis. The structure of the new compound was deduced from its comprehensive spectroscopic analysis including IR, EI-MS, ¹H NMR, ¹³C NMR, DEPT, COSY, HMBC and HMQC and was shown to be 4R^*-hydroxy-6S^*-tigloyloxyeudesma-7S^*-11 (13)-en-12-oic acid (1). Finally, the structure of the new compound was unambiguously confirmed by single-crystal X-ray analysis. The structure of known compounds 2 and 3 were identified by comparison of their spectral data with those reported in the literature.     

A 9,13-epoxylabdane from Colophospermum mopane

A new diterpene, 8(S),13(S)-dihydrogrindelic acid (2) was isolated from the seeds of Colophospermum mopane along with its previously described C-13 epimer (1). The structure of 2 was established primarily by NMR which required some revisions on the NMR shift assignments of 1. The importance of 1 and 2 as the missing links in the biosynthesis of 9,13-epoxylabdanes is briefly discussed.     

Acremonoside,a phenolic glucoside from the sea fan-derived fungus Acremonium polychromum PSU-F125

A new phenolic glucoside, acremonoside (1), along with two known compounds, F-11334 A₂ and 2,2-dimethyl-2H-chromen-6-ol, were isolated from the sea fan-derived fungus Acremonium polychromum PSU-F125. The structure of 1 was elucidated by spectroscopic techniques, acid hydrolysis and X-ray crystallographic analysis. The isolated compounds were tested for antibacterial, antimalarial, antimycobacterial and cytotoxic activities.     

New unsaturated fatty acid and other chemical constituents from the roots of Cola rostrata K. Schum. (Malvaceae)

Phytochemical investigation of the roots of Cola rostrata K. Schum. led to the isolation of a new unsaturated fatty acid, named rostratanic acid (1), together with fourteen known compounds, lignoceric acid, friedelan (7), friedelanone (8), bauerenol (3), lupeol (4), herranone (9), acotatarone A (11), betulinic acid (6), betulin (5), nonanedioc acid (2), arjunolic acid (10) stigmasterol, β−sitosterol, and β−sitosterol-3-O-β-D-glucopyranoside. The structure of the new compound as well as those of the known compounds were established by means of spectroscopic methods: NMR analysis (¹H and ¹³C NMR, ¹H–¹H–COSY, HSQC and HMBC) and high-resolution mass spectrometry (HR-ESI-MS), and by comparison with previously reported data. Two of those known compounds were modified chemically to afford three new derivatives. All those compounds were tested for their cytotoxic activity against the human cervix carcinoma KB-3-1 cells and their antibacterial activity against Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa and Staphylococcus aureus. Although the crude extract gave weak antibacterial activity, none of the isolated compounds showed antibacterial activity, and, only the prenylated derivative showed weak cytotoxicity. In addition, the chemotaxonomic significance of the species Cola rostrata is discussed.     

Bacicyclin,a new antibacterial cyclic hexapeptide from Bacillus sp. strain BC028 isolated from Mytilus edulis

A new cyclic hexapeptide, cyclo-(Gly-Leu-Val-IIe-Ala-Phe), named bacicyclin (1), was isolated from a marine Bacillus sp. strain associated with Mytilus edulis. The sequences of the amino acid building blocks of the cyclic peptide and its structure were determined by 1D- and 2D-NMR techniques. Marfey’s analysis showed that the amino acid building blocks had L-configuration in all cases except for alanine and phenylalanine, which had D-configuration. Bacicyclin (1) exhibited antibacterial activity against the clinically relevant strains Enterococcus faecalis and Staphylococcus aureus with minimal inhibitory concentration values of 8 and 12?µM, respectively. These results demonstrate the potential of marine bacteria as a promising source for the discovery of new antibiotics.     

A flavone C-Glycoside from Styela plicata

A known flavonoid triglycoside, apigenin 6-C-[α-_L-arabinopyranosyl-(1‴→2″)-β-_D-glucopyranoside]-7-O-β-_D- glucopyranoside (1), was isolated from the n-butanol extract of Styela plicata for the first time. The structure of 1 was established by spectroscopic methods and direct comparison with authentic samples on HPLC after acid hydrolysis as a new marine natural flavonoid. This work contributes to expand the knowledge about the chemical compositions of S. plicata and the chemotaxonomy of ascidians.     

α-Glucosidase inhibitory constituents from Chrozophora plicata

Five new secondary metabolites have been isolated from Chrozophora plicata including an acacetin derivative (1), three pyrrole alkaloids plicatanins A–C (2–4, resp.) and the bilactone plicatanone (5). Together with these compounds, the known compounds, β-sitosterol (6), methyl p-coumarate (7), 4-hydroxyphenylacetic acid (8), succinic acid (9), speranberculatine A (10), β-sitosterol-3-O-β-d-glucopyranoside (11) and apigenin-5-O-β-d-glucopyranoside (12) have also been isolated. The structures of isolates 1–12 were established by 1D (¹H, ¹³C) and 2D NMR (HMQC, HMBC, COSY) spectroscopy and mass spectrometry (EIMS, HREIMS, FABMS, HRFABMS). The structure of plicatanin A (3) was further confirmed through single crystal X-ray technique. Compounds 1–12 were evaluated for their inhibitory activity against the enzyme yeast α-glucosidase. The compound 4 was found to be most potent with IC₅₀ value 27.8 μM.     

Microseiramide from the freshwater cyanobacterium Microseira sp. UIC 10445

Microseiramide (1), a cyclic heptapeptide, was isolated from a sample of the freshwater cyanobacterium Microseira sp. UIC 10445 collected in a shallow lake in Northern Indiana. Taxonomic identification of UIC 10445 was performed by a combination of morphological and phylogenetic characterization. Phylogenetic analysis revealed that UIC 10445 was a member of the recently described genus Microseira, which is phylogenetically distinct from the morphologically similar genera, Moorea and Lyngbya. The planar structure of microseiramide (1) was determined by extensive 1D and 2D NMR experiments as well as HRESIMS analysis. The absolute configurations of amino acid residues were determined using acid hydrolysis followed by the advanced Marfey’s analysis. Microseiramide (1) is the first cyclic peptide reported from a Microseira sp., and the structure of microseiramide (1) is distinct from the previously known metabolites from cyanobacteria of the genera Moorea and Lyngbya.     

Identification of novel plasminogen activator inhibitor-1 inhibitors with improved oral bioavailability: Structure optimization of N-acylanthranilic acid derivatives

Novel plasminogen activator inhibitor-1 (PAI-1) inhibitors with highly improved oral bioavailability were discovered by structure-activity relationship studies on N-acyl-5-chloroanthranilic acid derivatives. Because lipophilic N-acyl groups seemed to be important for the anthranilic acid derivatives to strongly inhibit PAI-1, synthesis of compounds in which 5-chloroanthranilic acid was bound to a variety of highly lipophilic moieties with appropriate linkers was investigated. As the result it appeared that some of the derivatives possessing aryl- or heteroaryl-substituted phenyl groups in the acyl chain had potent in vitro PAI-1 inhibitory activity. Oral absorbability of typical compounds was also evaluated in rats, and compounds 40, 55, 60 and 76 which have diverse chemical structure with each other were selected for further pharmacological evaluation.     

Two new pyrrole derivatives isolated from Salacia amplifolia Merr

Two new pyrrole derivatives Salaciamole (1), Salaciaglycoside A (2), long with one known compound 1H-pyrrole-3-carboxylic acid (3) were isolated from the roots of Salacia amplifolia Merr (Hippocrateaceae). The structures of the new compounds were deduced from their comprehensive spectroscopic analysis including IR, HR-EI-MS, ¹H NMR, ¹³C NMR, DEPT, COSY, HMBC and HMQC. And the structure of the known compound was identified by comparison of their spectral data with those reported in the literature.     

Chemical constituents and chemotaxonomic study on the marine actinomycete Williamsia sp. MCCC 1A11233

The marine actinomycete Williamsia sp. MCCC 1A11233 was isolated from a deep sea sediment sample of the southwestern Indian Ocean. It was closely related to Williamsia limnetica L1505^T with a 16S rRNA gene sequence similarity value of 99.2%. A systematic investigation on its chemical constituents was performed in this study, which led to the isolation of one new (1) and 23 known (2–24) secondary metabolites. By mainly detailed analysis of the 1D and 2D NMR spectroscopic data and comparisons with the published data, the chemical structure of 1 was determined to be 3-benzyl-3α,4β-dihydroxypentan-2-one. Noteworthily, the question on which family Williamsia species should belong to was left unsolved at the first beginning when it was found in 1999. Interestingly, the result of this investigation consolidated that Williamsia should be placed a chemotaxonomic position in Nocardiaceae Family. Furthermore, 2-aminobenzoic acid derivatives (8–10) could be taken as chemotaxonomic markers for the genus of Williamsia.     

Isolation of phenolic constituents and characterization of antioxidant markers from sunflower (Helianthus annuus) seed extract

A new compound, benzyl alcohol β-d-apiofuranosyl-(1→6)-β-d-(4-O-caffeoyl) glucopyranoside (1), was isolated from the seed of sunflower (Helianthus annuus), together with eight known phenolic compounds: caffeic acid (2), methyl caffeoate (3), chlorogenic acid (4), 4-O-caffeoylquinic acid (5), 3-O-caffeoylquinic acid (6), methyl chlorogenate (7), 3,5-di-O-caffeoylquinic acid (8), and eriodictyol 5-O-β-d-glucoside (9). Their structures were elucidated on the basis of spectroscopic methods and chemical evidence. The antioxidative effect of the phenolic constituents from the sunflower seeds was also evaluated based on the oxygen-radical absorbance capacity (ORAC), and the fraction containing caffeic acid derivatives showed a high antioxidant potency.