New metabolites from the alga-derived fungi Penicillium thomii Maire and Penicillium lividum Westling

A new meroterpenoid, austalide H acid ethyl ester (1), 5-(2′,4′-dihydroxy-6′-methylphenyl)-3-methylfuran-2-carboxylic acid (2), 5-(2′-hydroxy-6′-methylphenyl)-3-methylfuran-2-carboxylic acid (3) and 5-((6′-methyl-4′-oxo-3′,4′-dihydro-2H-pyran-2′-yl)methyl)-3-methylfuran-2-carboxylic acid (4), along with six known compounds, austalides H, J, K, and P (5–8), questin (9) and sulochrin (10) were isolated from the lipophilic extract of the alga-derived fungi Penicillium thomii KMM 4645 and Penicillium lividum KMM 4663. The structures of the isolated compounds were determined based on spectroscopic methods. The austalides showed significant inhibitory activity against endo-1,3-β-d-Glucanase from a crystalline stalk of the marine mollusk Pseudocardium sachalinensis.     

Illigerones A and B,two new long-chain secobutanolides from Illigera henryi W. W. Sm.

Two new long-chain secobutanolides, illigerones A (1) and B (2), together with five known compounds, actinodaphnine (3), cryptodorine (4), β-sitosterol (5), daucosterol (6), and stigmasterol (7) were isolated from Illigera henryi W. W. Sm. The structures of 1 and 2 were identified by HRESIMS, EIMS, 1D/2D NMR, and electronic circular dichroism (ECD) spectra. Compound 1 exhibited the moderate cytotoxic activities against five tumour cells. This is the first report of secobutanolides isolated from plants of Hernandiaceae.     

New polyacetylene and other compounds from Bupleurum chinense and their chemotaxonomic significance

Here, we isolated a new polyacetylene, (2Z,8E)-heptadecadiene-10-oxo-4,6-diyn-1-ol (1), an oxylipin (2), eight phenolic compounds (3–10), and 15 saponins (11–25) from the roots of Bupleurum chinense. We elucidated their structures by analysis of 1D and 2D-NMR spectroscopic data and mass spectrometry, and by comparison with those of related metabolites. This is the first report of the presence of compounds 2 and 6 in the Bupleurum spp.. Chemotaxonomic significance of these compounds is described herein.     

Altertoxins with potent anti-HIV activity from Alternaria tenuissima QUE1Se,a fungal endophyte of Quercus emoryi

Screening of a small library of natural product extracts derived from endophytic fungi of the Sonoran desert plants in a cell-based anti-HIV assay involving T-cells infected with the HIV-1 virus identified the EtOAc extract of a fermentation broth of Alternaria tenuissima QUE1Se inhabiting the stem tissue of Quercus emoryi as a promising candidate for further investigation. Bioactivity-guided fractionation of this extract led to the isolation and identification of two new metabolites, altertoxins V (1) and VI (2) together with the known compounds, altertoxins I (3), II (4), and III (5). The structures of 1 and 2 were determined by detailed spectroscopic analysis and those of 3–5 were established by comparison with reported data. When tested in our cell-based assay at concentrations insignificantly toxic to T-cells, altertoxins V (1), I (3), II (4), and III (5) completely inhibited replication of the HIV-1 virus at concentrations of 0.50, 2.20, 0.30, and 1.50 μM, respectively. Our findings suggest that the epoxyperylene structural scaffold in altertoxins may be manipulated to produce potent anti-HIV therapeutics.     

Chemical constituents from Valeriana officinalis L. var. Iatifolia Miq. and their chemotaxonomic significance

Twenty-one compounds, including four monoterpenoids (1–4) (two new natural products, 1 and 2), four sesquiterpenes (5–8), two iridoids (9 and 10), four steroids (11–14), five phenolic compounds (15–19), and two alkaloids (20 and 21), were isolated from the roots of Valeriana officinalis L. var. Iatifolia Miq. Their chemical structures were established by spectroscopic methods and further confirmed by comparison with published data in the literature. Among them, eight compounds (1, 2, 6–8, 13, 18, and 21) are being reported from the family Valerianaceae for the first time, and compounds 9–12 were obtained from V. officinalis for the first time. The chemotaxonomic significance of the isolated compounds is discussed.     

Neuroactive diol and acyloin metabolites from cone snail-associated bacteria

The bacterium Gordonia sp. 647 W.R.1a.05 was cultivated from the venom duct of the cone snail, Conus circumcisus. The Gordonia sp. organic extract modulated the action potential of mouse dorsal root ganglion neurons. Assay-guided fractionation led to the identification of the new compound circumcin A (1) and 11 known analogs (2–12). Two of these compounds, kurasoin B (7) and soraphinol A (8), were active in a human norepinephrine transporter assay with K_i values of 2575 and 867 nM, respectively. No neuroactivity had previously been reported for compounds in this structural class. Gordonia species have been reproducibly isolated from four different cone snail species, indicating a consistent association between these organisms.     

A new flavanone sulfonate and other phenolic compounds from Fumana montana

The phytochemical study of ethyl acetate and n-butanol extracts of Fumana montana Pomel yielded a new flavanone sulfonate named naringenin-8-sulfonate (1), in addition to nine known compounds including two flavonols; tellimoside (2) and isoquercetrin (3), two flavanols; (−)-gallocatechin (4) and (−)-epigallocatechin (5), one benzophenone glucoside; iriflophenone-2-O-β-glucoside (6), one phenolic glucoside; (−)-rhododendrin (7) and three benzoic acid derivatives; p-hydroxybenzoic acid (8), gallic acid (9) and methyl gallate (10). It should be noted that this is the first report of compounds (2) and (6) in Cistaceae family. The structures of the isolated compounds were determined by comprehensive 1D and 2D NMR analysis, mass spectrometry, IR and by comparison with literature data.     

New labdane diterpenes from the aerial parts of Scoparia dulcis L.

Three new labdane-derived diterpenes, dulcinodal (1), dulcinodiol (2), and scopadiol decanoate (3) were isolated from the aerial parts of Scoparia dulcis. The structures were determined by extensive NMR studies and comparison of their spectral data with related compounds.     

Ehrenasterol and biemnic acid; new bioactive compounds from the Red Sea sponge Biemna ehrenbergi

In continuation of our efforts to identify bioactive compounds from the Red Sea marine sponges, we have recently investigated the organic extract of the sponge Biemna ehrenbergi. This study resulted in the isolation of eight compounds including a new sterol, ehrenasterol (1), a new C₂₄-acetylenic acid, biemnic acid (2), together with six known compounds including a hopanoid, three steroids and two nucleosides. The isolated compounds were identified as (22E)-ergosta-22-ene-8,14-epoxy-3,7-dione (1), (E)-tetracos-8-en-5-ynoic acid (2), (22E)-ergosta-5,8,22-trien-7-one-3β-ol (3), 32,35-anhydrobacteriohopanetetrol (4), (24R)-ergosta-6,22-diene-5,8-epidioxy-3-ol (5), melithasterol B (6), thymidine (7) and 2′-deoxyuridine (8). The structures of the isolated compounds were assigned by different spectral data including 1D and 2D NMR (COSY, HSQC, and HMBC) and high-resolution mass spectrometry. Compound 1 displayed inhibition zone of 20 mm at 100 μg/disc against Escherichia coli in the disc diffusion assay. Similarly, compounds 2 and 4 displayed inhibition zones of 20 and 18 mm respectively against Candida albicans at the same concentration. Compounds 1–3 displayed weak cytotoxic activity against human colon adenocarcinoma (HCT-116) cancer cell line.     

Vernoguinamide: A new ceramide and other compounds from the root of Vernonia guineensis Benth. and their chemophenetic significance

The chemical investigation of the roots of Vernonia guineensis Benth. (Asteraceae) resulted in the isolation of a new ceramide, named vernoguinamide (1), together with fifteen known compounds, including three anthraquinones, physion (2), erythroglaucin (3) and emodin (4), three triterpenoids, hop-17(21)-en-3β-yl acetate (5), lupeol (6) and betulinic acid (7), six steroids, vernoguinoside A (8), vernoguinoside (9), β-sitosterol 3-O-β-D-glucoside (10), stigmasterol 3-O-β-D-glucoside (11), stigmasterol (12) and β-sitosterol (13) and three fatty acid derivatives, tetracosanoic acid (14), tricosanic acid (15) and arachidic acid glycerol ester (16). The structure of the new compound as well as those of the known compounds were established by spectrometric analysis including HRESI-MS, 1D and 2D-NMR and by comparison with the previously reported data. Among these compounds, the anthraquinones 2–4 and the triterpene 5 were isolated for the first time from Vernonia genus and compounds 6, 7 and 14–16 were extracted for the first time from the species. The isolated compounds were tested for their antibacterial activity and 3, 8 and 9 were the most active compounds against the tested bacteria. Furthermore, the chemophenetic relationships of the isolated compounds and their significance were also discussed.     

Chemical constituents from Mentha canadensis

Phytochemical investigation on Mentha canadensis led to the isolation of two new compounds, 3,4-dihydro-3,6,7-trihydroxy-2(1H)-quinolinone (1), (E)-2-methoxy-2- oxethyl-3-(4-hydroxyphenyl) acrylate (2), along with nine known phenolic compounds, syringic acid (3), p-coumaric acid (4), esculetin (5), methyl rosmarinate (6), nepetoidin B (7), syringaresinol (8), methyl ester of caffeoyl glycollic acid (9), 2″,3″-diacetylmartynoside (10) and bracteanolide A (12). Additionally, cis-3-[2-[1-(3,4-dihydroxyphenyl)-1-hydroxymethyl]-1,3-benzodioxol-5-yl]-(E)-2-propenoic acid (11), which was isolated as a natural product for the first time. All these compounds were reported for the first time from this species, and their structures were elucidated by spectroscopic techniques. Compound 11 may be a useful chemotaxonomic marker for M. canadensis. The p-coumaric acid derivatives identified in the present investigation may have chemotaxonomic significance at the generic level.     

Isopimarane diterpenes and flavan derivatives from the twigs of Caesalpinia furfuracea

The first phytochemical investigation of Caesalpinia furfuracea twigs led to the isolation and identification of four new compounds including two isopimarane diterpenes, caesalfurfuric acids A (1) and B (2), and two flavans, (2R)-caesalflavans A (5) and B (6), together with four known compounds, 4-epi-isopimaric acid (3), methyl (E)-3-(3,4-dihydroxyphenyl)acrylate (4), (E)-resveratrol (7) and oxyresveratrol (8). Their structures were elucidated by intensive spectroscopic analysis. Compound 1 was found to exhibit antibacterial activity against MRSA SK1 with an MIC value of 16 μg/mL.     

Minor phenolics from Angelica keiskei and their proliferative effects on Hep3B cells

A new coumarin, (?)-cis-(3′R,4′R)-4′-O-angeloylkhellactone-3′-O-β-d-glucopyranoside (1) and two new chalcones, 3′-[(2E)-5-carboxy-3-methyl-2-pentenyl]-4,2′,4′-trihydroxychalcone (4) and (±)-4,2′,4′-trihydroxy-3′-{2-hydroxy-2-[tetrahydro-2-methyl-5-(1-methylethenyl)-2-furanyl]ethyl}chalcone (5) were isolated from the aerial parts of Angelica keiskei (Umbelliferae), together with six known compounds: (R)-O-isobutyroyllomatin (2), 3′-O-methylvaginol (3), (?)-jejuchalcone F (6), isoliquiritigenin (7), davidigenin (8), and (±)-liquiritigenin (9). The structures of the new compounds were determined by interpretation of their spectroscopic data including 1D and 2D NMR data. All known compounds (2, 3, and 6–9) were isolated as constituents of A. keiskei for the first time. To identify novel hepatocyte proliferation inducer for liver regeneration, 1–9 were evaluated for their cell proliferative effects using a Hep3B human hepatoma cell line. All isolates exhibited cell proliferative effects compared to untreated control (DMSO). Cytoprotective effects against oxidative stress induced by glucose oxidase were also examined on Hep3B cells and mouse fibroblast NIH3T3 cells and all compounds showed significant dose-dependent protection against oxidative stress.     

Chemical constituents from the pericarps of Zanthoxylum bungeanum and their chemotaxonomic significance

The phytochemical study of the pericarps of Zanthoxylum bungeanum Maxim under the guidance of bioactivity led to the isolation of 18 compounds, including a new isobutylhydroxyamide (1) and 17 known compounds, i.e. six alkylamides (2–7), five coumarins (8–12), one benzene derivative (13), three flavonoids (14–16), and two sterols (17–18). Their structures were elucidated based on extensive spectroscopic methods (HRESIMS, 1D and 2D NMR experiments) and by comparison with literature data. New compound (1) and known compound (2) are cis-trans isomeric isobutylhydroxyamides. Among them, compounds 9, 10, and 12 were isolated for the first time from Z. bungeanum, compound 11 was firstly recovered from the genus Zanthoxylum, and compound 14 was reported for the first time from the Rutaceae family. The chemotaxonomic significance of isolated compounds from Z. bungeanum is discussed.     

Chemical constituents from Cistanche sinensis (Orobanchaceae)

Phytochemical investigation of 70% aqueous EtOH extract of Cistanche sinensis led to the isolation of fifteen compounds (1–15), including nine phenylethanoid glycosides (PhGs, 1–9), five iridoid glycosides (10–14), and one lignan glycoside (15). Their structures were determined on the basis of 1D- and 2D-NMR experiments and by comparison with physical data of known compounds. Among the isolated compounds, 1 was identified as a new compound, three compounds (9, 14, and 15) were firstly reported from the genus Cistanche, and seven compounds (2–6, 11, and 12) were isolated from C. sinensis for the first time. PhGs with a 6′-O-rhamnosyl moiety such as cistansinenside B (1), poliumoside (7), and 2′-O-acetylpoliumoside (9) could serve as chemotaxonomic markers to differentiate C. sinensis from other species of Cistanche.     

Voulkensin C–E,new 11-oxocassane-type diterpenoids and a steroid glycoside from Caesalpinia volkensii stem bark and their antiplasmodial activities

A bioassay guided isolation of potential antimalarial molecules from the stem bark of Caesalpinia volkensii Harms (Fabaceae) achieved three new 11-oxocassane-type diterpenoids named voulkensin C (1), D (2) and E (3) together with one steroid glycoside named 3-O-[β-glucopyranosyl(1→2)-O-β-xylopyranosyl]-stigmasterol (4) and seven other known compounds including stigmasterol (5), β-sitosterol (6), oleanolic acid (7), 3-β-acetoxyolean-12-en-28-methyl ester (8), voucap-5-ol (9), caesadekarin C (10), deoxycaesaldekarin C (11). The structures of the new compounds were determined on the basis of extensive spectroscopic data (IR, MS, ¹H and ¹³C NMR and 2D NMR) analyses. The polar extracts revealed moderate to good antiplasmodial activities against chloquine-sensitive (D6) and -resistant strains (W2) of Plasmodium falciparum. Whereas the pure isolates exhibited limited to moderate antiplasmodial activities with compound 4 showing the highest antiplasmodial activities (IC₅₀ values of 4.44 ± 0.88 and 2.74 ± 1.10 μM against D6 and W2 strains, respectively). These results suggest a possible contribution of phytochemicals from C. volkensii stem bark towards inhibition of plasmodial parasites’ growth hence potential antimalarial.     

Antibacterial and antioxidant activities of compounds isolated from the leaves of Symphonia globulifera (Clusiaceae) and their chemophenetic significance

The phytochemical study was done on the methanol extract from of the leaves of Symphonia globulifera. This plant has been used in traditional medicine to treat of different ailments such as malaria, diseases of the skin, diabetes, cough, intestinal worms, pre-hepatic jaundice and fever. Chromatographic fractionation and purification of this extract led to the isolation and characterization of twelve compounds (1–12) including pristriol (1), robustaflavone (2), polycarpol (3), 7''-O-methylrobustaflavone (4), amentoflavone (5), stigmasterol glucoside (6), epicatechin (7), apigenin (8), luteolin (9), 1,5-dihydroxyxanthone (10), β-sitosterol 3-β-D-glucopyranoside (11) and a mixture of stigmasterol and β-sitosterol (12). The structures of compounds 1–12 were elucidated on the basis of 1D and 2D NMR, mass spectrometric and the spectroscopic data as well as comparison with the literature. All these compounds were isolated for the first time from Symphonia genus. The NMR spectra and structure elucidation of compound 1 were reported for the first in the literature. The antibacterial and antioxidant activities of three of these compounds were evaluated. The chemophenetic significance of these compounds is also discussed.     

Isoprenylated flavonoids from the roots of Sophora tonkinensis

Two new isoprenylated flavanones, tonkinochromanes J (1) and K (2), and a new isoprenylated dihydrochalcone, tonkinochromane L (3), were isolated from the roots of Sophora tonkinensis along with four known compounds (4-7). Their structures were determined by means of spectroscopic analyses, including HRMS, IR, ¹H and ¹³C NMR and 2D experiments (COSY, HSQC, and HMBC), and comparison with known related compounds.     

New polyoxygenated cyclohexenes isolated from Uvaria rufa and cinnamtannin B1 isolated from Nephelium hypoleucum with TRAIL-resistance-overcoming activity

Bioactivity-guided isolation of Uvaria rufa leaves and Nephelium hypoleucum bark resulted in the successful isolation of nine compounds (1–9) bearing a new polyoxygenated cyclohexene scaffold: zeylenol-6-shikimate (1), (−)-zeylenol (2), microcarpin A (3), uvarigranol F (4), quercetin (5), kaempferol (6), and p-coumaric acid (7) from U. rufa, and epicatechin (8) and cinnamtannin B1 (9) from N. hypoleucum. The structures of the isolated compounds were elucidated using various spectroscopic techniques. All compounds, except for 7, exhibited weak-to-strong TRAIL-resistance-overcoming activity and an increased gastric cancer cell line (AGS) inhibition by 17–32% as compared to the treatment with the compounds alone. Compounds 3 and 9 were studied for their ability to overcome TRAIL resistance using western blot analysis, which indicated that they sensitised AGS cells to apoptosis via both extrinsic and intrinsic pathways by increasing the expression of several proapoptotic proteins (cleaved caspase-3, −8, and −9) and by decreasing the expression of anti-apoptotic protein Bcl-2.     

Chemical constituents from the fresh flower buds of Musa nana and their chemotaxonomic significance

Phytochemical study on the fresh flower of Musa nana Lour. provided seventeen known compounds including two alkaloids, 3-(hydroxyacetyl)-indole (1), bi-indol-3-yl (2), two terpenoids, 5-[(1R)-1-hydroxy-2,6,6-trimethyl-4-oxo-2-cyclohexen-1-yl]-3-methyl-, (2Z, 4E) −2, 4-pentadienoic acid (Valdes), 5, 6(S), 7, 7a(R)-tetrahydro-6-hydroxy-4,4-dimethyl-2(4H)-benzofuranone (4), seven phenols (5–11), three phenylphenalenones, 2-hydroxy-4-(4-methoxyphenyl)-1H-phenalen-1-one (12), 2-methoxy-9-phenyl-1H-phenalen-1-one (13), 2-methoxy-9-(4-methoxyphenyl)-1H-phenalen-1-one (14), and three lipids (15–17). In the present study, all the compounds were isolated for the first time from the species M. nana. Ten compounds including 1-8 and 15-16 have never been previously encountered in the Musaceae family. Furthermore, the chemotaxonomic significance of these isolates was also discussed.