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.     

Novel spiro-sesquiterpene from the mushroom Anthracophyllum sp. BCC18695

A novel spiro-sesquiterpene, anthracophyllic acid (1), and a new aristolane sesquiterpene, anthracophyllone (2), were isolated from the mushroom Anthracophyllum sp. BCC18695, together with seven known compounds including aurisins A (3), G (4), K (5), nambinones A, C, axinysones A, and B. The relative configuration of 1 and the hitherto unknown absolute stereochemistry of 3 were determined based on X-ray spectroscopic data. Biological activities including antimalarial activity against Plasmodium falciparum K1 strain, antibacterial property against Bacillus cereus, and cytotoxicity against MCF-7, KB, NCI-H187, and Vero cells of the isolated compounds were also evaluated     

Snyderol derivatives from Laurencia obtusa collected in Corsica

8-keto-10-dehydrobromo-γ-snyderol (1), a new sesquiterpene exhibiting the unusual γ-snyderane skeleton, was isolated from the ethyl acetate extract of Laurencia obtusa collected in Ajaccio (Corsica, France). (1) was isolated and fully characterized by detailed spectroscopic analysis. Six known compounds were identified after column chromatography steps using a ¹³C NMR based computerized method developed in our laboratory: α-snyderol (2), two rearranged derivatives of α-snyderol (3,4), 8-keto-10-dehydrobromo-β-snyderol (5), β-snyderol (6) and 8-hydroxy-β-snyderol (7).     

Reduced perylenequinone derivatives from an endophytic Alternaria sp. isolated from Pinus ponderosa

The consecutive solvent extraction of endophytic Alternaria sp. (DC401) isolated from Pinus ponderosa followed by chromatographic techniques led to the isolation of five perylenequinone compounds and one dihydronaphthaquinone derivative, which include three new perylenequinones (1–3). The compounds were identified as 6-methoxy-3,6a,7,10-tetrahydroxy-4,9-dioxo-4,5,6,6a,6b,7,8,9-octahydroperylene (1), 3,6a,9,10-tetrahydroxy-7,8-epoxy-4-oxo-4,5,6,6a,6b,7,8,9-octahydroperylene (2), 6-methoxy-3,6a,9,10-tetrahydroxy-7,8-epoxy-4-oxo-4,5,6,6a,6b,7,8,9-octahydroperylene (3), 3,6a,7,10-tetrahydroxy-4,9-dioxo-4,5,6,6a,6b,7,8,9-octahydroperylene (altertoxin I) (4), 3,6a,7,10-tetrahydroxy-4,9-dioxo-4,6a,6b,7,8,9-hexahydroperylene (dehydroaltertoxin I) (5), and 7-chloroscytalone (6). Structure of compounds 1–6 was determined on the basis of detailed spectroscopic analysis, as well as by comparison with literature reports. The antileismanial, antimicrobial, antimalarial and in vitro cytotoxic activities of compounds 1–6 were evaluated.     

Sesquiterpene lactones from the leaves of Magnolia sirindhorniae

Five sesquiterpene lactones, costunolide (1), santamarine (2), reynosin (3), parthenolide (4), and lipiferolide (5), were isolated from the leaves of Magnolia sirindhorniae. Their structures were identified by analysis of spectroscopic data and comparison with those reported in the literature. Compound 5 was isolated from the Magnolia for the first time, and this is the first report of the isolation of the sesquiterpene lactones from M. sirindhorniae.     

Endoperoxide polyketides from a Chinese Plakortis simplex: Further evidence of the impact of stereochemistry on antimalarial activity of simple 1,2-dioxanes

Chemical investigation of the organic extract obtained from the sponge Plakortis simplex collected in the South China Sea afforded five new polyketide endoperoxides (2 and 4–7), along with two known analogues (1 and 3). The stereostructures of these metabolites have been deduced on the basis of spectroscopic analysis and chemical conversion. The isolated endoperoxide derivatives have been tested for their in vitro antimalarial activity against Plasmodium falciparum strains, showing IC₅₀ values in the low micromolar range. The structure–activity relationships were analyzed by means of a detailed computational investigation and rationalized in the light of the mechanism of action proposed for this class of simple antimalarials. The relative orientation of the atoms involved in the putative radical generation and transfer reaction was demonstrated to have a great impact on the antimalarial activity. The resulting 3D pharmacophoric model can be a useful guide to design simple and effective antimalarial lead compounds belonging to the class of 1,2-dioxanes.     

Phenolic compounds and triterpenes from the roots of Vaccinium dunalianum Wight and their chemotaxonomic significance

Eight phenolic compounds, including two catechins (1 and 2), two proanthocyanidins (3 and 4), three lignans (5–7), and one phenol (8), were isolated from roots of Vaccinium dunalianum Wight (Ericaceae), together with two triterpenes (9 and 10). All of them were isolated from the title plant for the first time. Their chemical structures were established based on the extensive MS and NMR spectroscopic analysis. Compounds 6–10 acquired initially from the genus Vaccinium, showed some significances in chemotaxonomy.     

Synthesis of antimalarial amide analogues based on the plant serrulatane diterpenoid 3,7,8-trihydroxyserrulat-14-en-19-oic acid

A plant-derived natural product scaffold, 3,7,8-trihydroxyserrulat-14-en-19-oic acid (1) was isolated in high yield from the aerial parts of the endemic Australian desert plant Eremophila microtheca. This scaffold (1) was subsequently used in the generation of a series of new amide analogues via a one-pot mixed anhydride amidation using pivaloyl chloride. The structures of all analogues were characterized using MS, NMR, and UV data. The major serrulatane natural products (1–3), isolated from the plant extract, and all amide analogues (6–15) together with several pivaloylated derivatives of 3,7,8-trihydroxyserrulat-14-en-19-oic acid (16–18) were evaluated for their antimalarial activity against 3D7 (chloroquine sensitive) and Dd2 (chloroquine resistant) Plasmodium falciparum strains, and preliminary cytotoxicity data were also acquired using the human embryonic kidney cell line HEK293. The natural product scaffold (1) did not display any antimalarial activity at 10 µM. Replacing the carboxylic acid of 1 with various amides resulted in moderate activity against the P. falciparum 3D7 strain with IC₅₀ values ranging from 1.25 to 5.65 µM.     

Synthesis and antimalarial evaluation of a screening library based on a tetrahydroanthraquinone natural product scaffold

As part of a research program aimed at discovering new antimalarial leads from Australian macrofungi a unique fungi-derived prefractionated library was screened against a chloroquine-sensitive Plasmodium falciparum line (3D7) using a radiometric growth inhibition assay. A library fraction derived from a Cortinarius species displayed promising antimalarial activity. UV-guided fractionation on the CH₂Cl₂/MeOH extract from this fungus resulted in the isolation of four known compounds: (1S,3R)-austrocortirubin (1), (1S,3S)-austrocortirubin (2), 1-deoxyaustrocortirubin (3), and austrocortinin (4). Compound 2 was used as a natural product scaffold in the parallel solution-phase synthesis of a small library of N-substituted tetrahydroanthraquinones (5–15). All compounds (1–15) were tested in vitro against P. falciparum 3D7 parasites and (1S,3S)-austrocortirubin (2), the major fungal constituent, was shown to be the most active compound with an IC₅₀ of 1.9 μM. This compound displayed moderate cytotoxicity against neonatal foreskin fibroblast (NFF) cells with an IC₅₀ of 15.6 μM.     

Chemical constituents from the roots of Euphorbia nematocypha Hand.-Mazz.

A new myrsinol-type diterpene (1), three myrsinol-type diterpenes (2–4), three ent-abietane-type diterpenes (5–7), one tigliane-type diterpene (8), two cycloartane-type triterpenes (9–10), and two tirucallane-type triterpenes (11–12) were isolated from the roots of Euphorbia nematocypha Hand.-Mazz. Their structures were identified by spectroscopic analyses and by comparison of their spectral data with those reported in the literature. Compound 12 was isolated and reported from plants for the first time. All compounds were isolated from E. nematocypha for the first time.     

Chemical constituents from the roots of Peucedanum praeruptorum Dunn and their chemotaxonomic significance

Chemical investigation on the roots of Peucedanum praeruptorum Dunn afforded 15 compounds, including five linear furocoumarins (1–5), six angular pyranocoumarins (6–11), two simple coumarins (12 and 13), a benzaldehyde derivative (14), and a phenylpropanoid glycoside (15). The structures of these compounds were established via spectroscopic analysis and comparison of their NMR data with the literature. Compound 1 was a new linear furocoumarin glycoside, while compounds 10–12, 14 and 15 were isolated from P. praeruptorum for the first time. The chemotaxonomic significance of these isolated compounds was summarized herein.     

Bioactive constituents of Helianthus tuberosus (Jerusalem artichoke)

In a cytotoxicity-guided study using the MCF-7 human breast cancer cell line, nine known compounds, ent-17-oxokaur-15(16)-en-19-oic acid (1), ent-17-hydroxykaur-15(16)-en-19-oic acid (2), ent-15β-hydroxykaur-16(17)-en-19-oic acid methyl ester (3), ent-15-nor-14-oxolabda-8(17),12E-dien-18-oic acid (4), 4,15-isoatriplicolide angelate (5), 4,15-isoatriplicolide methylacrylate (6), (+)-pinoresinol (7), (?)-loliolide (8), and vanillin (9) were isolated from the chloroform-soluble subfraction of a methanol extract of the whole plant of Helianthus tuberosus collected in Ohio, USA. This is the first time that diterpenes have been isolated and identified from this economically important plant. The bioactivities of all isolates were evaluated using the MCF-7 human breast cancer cell line as well as a soybean isoflavonoid defense activation bioassay. The results showed that two germacrane-type sesquiterpene lactones, 5 and 6, are cytotoxic agents. While compounds 2, 3, 5 and 6 blocked isoflavone accumulation in the soybean, the norisoprenoid (?)-loliolide (8) was somewhat stimulatory of these defense metabolites.     

Four new glycosides from the seeds of Cassia obtusifolia

Four new glycosides, including one anthraquinone glycoside (1), one naphthalene glycoside (2), and two naphthopyrone glycosides (3–4), with 10 known compounds (5–14) were isolated from the seeds of Cassia obtusifolia L. The new structures were determined by spectroscopic analysis and chemical transformations.     

Lanostane triterpenoids from cultivated fruiting bodies of the basidiomycete Ganoderma orbiforme

A new 3,4-seco-27-norlanostane triterpene, ganoboninketal D (1), a new lanostane, (24S)-3-oxo-7α,24,25-trihydroxylanosta-8-ene (2), together with six known lanostanes (3–8), were isolated from cultivated fruiting bodies of the basidiomycete Ganoderma orbiforme. The structures were elucidated on the basis of NMR spectroscopic and mass spectrometry data, and the structures 1 and 2 were further confirmed by chemical correlations to ganoboninketal C and ganodermanondiol, respectively. All isolated compounds were inactive in the antitubercular and antimalarial activity assays against Mycobacterium tuberculosis H37Ra and Plasmodium falciparum K1, respectively, except that compound 8 exhibited weak antitubercular activity (MIC 50 μg/ml).     

Cytotoxic naphthoquinone and a new succinate ester from the soil fungus Fusarium solani PSU-RSPG227

A new naphthoquinone, solaninaphthoquione (1), and a new succinate ester derivative, 4-(4-hydroxyphenethoxy)-4-oxobutanoic acid (2), were isolated from the soil fungus Fusarium solani PSU-RSPG227 together with five previously reported compounds; javanicin (3), monaspilosin (4), aspergillol B (5), tyrosol (6) and 4-hydroxyphenylacetic acid (7). Their structures were elucidated primarily by NMR spectroscopic data. Due to paucity of materials, compounds 2, 4 and 5 as well as analogues of 5 were prepared for biological activity evaluation. Compound 1 showed significant cytotoxic activity against breast cancer (MCF-7) cells and mild cytotoxic activity against oral human carcinoma (KB) cells (IC₅₀ values of 21.3 and 22.6 μM, respectively) compared to standard compounds. Compound 1 also displayed weak antimalarial activity (IC₅₀ of 26.1 μM).     

Chemical constituents of the medicinal plant Indigofera spicata Forsk (Fabaceae) and their chemophenetic significance

The chemical investigation of the whole plant of Indigofera spicata Forsk (Fabaceae), a medicinal plant from Cameroon, resulted in the isolation of a new benzofuran, named spibenzofuran (1a), together with ten known secondary metabolites including one benzofuran (2), one flavonoid (3), one saponin (6), two triterpenes (4 and 5), two steroids (8 and 11), one phthalate (7) and two fatty acids (9 and 10). All these compounds have been isolated for the first time from this plant. The structures of the isolated compounds were established by spectroscopic analysis including HR-ESI-MS, 1D and 2D NMR and by comparison of our data with the reported data. The isolated compounds might be considered as the chemophenetic markers of this species, and antibacterial and urease inhibitory activities of some isolated compounds were assessed.     

Phytochemical constituents from the stem barks of Goniothalamus tapis Miq

Phytochemical investigation on the stem bark of Goniothalamus tapis Miq. led to the isolation of seven known styryl-lactones, 3-acetyl-isoaltholactone (1), goniothalamin (2), isoaltholactone (3), cheliensisin A (4), 7-epi-goniofufurone (5), goniopypyrone (6), garvensintriol (7), and two steroids, stigmasterol (8) and β-sitosterol (9). The structures of all the compounds were elucidated based on the analysis of spectroscopic data and comparison with reported literature. The chemotaxonomic significance of all these compounds were summarized. Among all the styryl-lactones, compound 1 was isolated naturally from plant for the first time while compounds 4, 5 and 7 have not been previously reported in Goniothalamus tapis Miq. Compound 2 was the first styryl-lactone isolated from many species of Goniothalamus including other families such as Cucurbitaceae, Lauraceae, Stemonaceae and Apocynaceae). Compounds 3 and 6 were found in ten species of Goniothalamus where the latter were also found in other genus (Polyalthia Blume).     

Chemical constituents of Peperomia tetraphylla (Forst. F.) Hooker et Arnott

Sixteen compounds were isolated from the whole herbs of Peperomia tetraphylla (Forst. F.) Hooker et Arnott by phytochemical methods, including eight flavonoids (1–3, 6, 7, 14–16), three lignans (8–10), three beta sitosterols (4, 5, 11), and two phenolic acids (12, 13). Their structures were identified by the analysis of NMR and MS, as well as the comparisons to the reported data. Among them, 2″-O-xylosylisoswertisin (14) was firstly isolated from the Piperaceae family, as well as ten compounds (1–4, 7, 10–11, 13, 15–16) were isolated from P. tytraphylla for the first time. Moreover, the chemotaxonomic significance of constituents isolated from P. tytraphylla was also discussed.     

A new meroterpenoid from endophytic fungus Talaromyces amestolkiae CS-O-1

Talaromyces amestolkiae CS-O-1, isolated from Tripterygium Wilfordii Hook. f., was identified based on its ITS and 18S rDNA gene sequencing. A new meroterpenoid, chrodrimanin T (1), along with six known compounds, nicotinamide (2), penipyridone D (3), penipyridone A (4), 3-benzylidene-8,8a-dihydroxy-2-methyl-hexahydro-pyrrolo[1,2-a]pyrazine-1,4-dione (5), butyl-isobutyl-phthalate (6), and aspergillumarin A (7), were isolated from Talaromyces amestolkiae CS-O-1. The structures and relative configurations of these compounds were established by the analysis of HRMS, 1D and 2D-NMR spectroscopy and the comparison with data in the literature. The compounds 2–6 were first isolated from Talaromyces genus. Herein, the chemotaxonomic significance of these compounds is described.