Bioactive styryllactones,two new naphthoquinones and one new styryllactone,and other constituents from Goniothalamus scortechinii

Two new naphthoquinones, goniothalaminone A (1) and B (2), and a new styryllactone, (?)-8-epi-9-deoxygoniopypyrone acetate (12) together with one known naphthoquinone (3), one known indolequinone (4), one known 1-azaanthraquinone (5), six known styryllactones (6–11) and one known sesquiterpene (13) were isolated from the roots and leaves of Goniothalamus scortechinii. The structures of the new compounds were elucidated by spectroscopic analysis and of the known compounds by comparison of their physical, UV, IR, ¹H and ¹³C NMR data with those of published compounds. Antiplasmodial, antimycobacterial and cytotoxic activities of the styryllactones were evaluated. Compounds 6–10 exhibited cytotoxic against human cancer cell lines, KB, BC and NCI-H187 with IC₅₀ values ranging from 0.13 to 11.7 μg/ml.     

Xanthine oxidase inhibitors isolated from Piper nudibaccatum

Two new hydroxychavicol analogs nudibaccatumin A (1) and B (2), together with twenty known compounds were isolated from the methanol extract of Piper nudibaccatum. Their structures were elucidated by extensive spectroscopic analyses (1D and 2D NMR, HRESIMS, UV, IR and polarimetry). Hydroxychavicol is a known inhibitor of xanthine oxidase (XO). In the present study, hydroxychavicol and 5 natural analogs (1–5) were evaluated for their XO inhibitory activity. Neotaiwanensol B (3) (IC₅₀ = 0.28 μM) showed a greater inhibitory effect than hydroxychavicol and allopurinol (the positive control). Two new compounds 1 and 2 showed a moderate inhibition activity with an IC₅₀ value of 62.94 μM and 70.67 μM, respectively.     

Inhibitory constituents of the heartwood of Dalbergia odorifera on nitric oxide production in RAW 264.7 macrophages

Two new isoflavanones (1 and 13), along with 25 known compounds (2–12, 14–27), were isolated from the EtOAc-soluble fraction of the heartwood of Dalbergia odorifera by following their potential to inhibit the LPS-induced nitric oxide production in RAW 264.7 cells. The structures of the isolated compounds were established by spectroscopic data such as ¹D, ²D NMR and MS spectrometry. Among the isolated compounds, (2S)-pinocembrin (26), showed the most potent inhibitory effect with IC₅₀ value of 18.1 μM.     

Antimycobacterial dihydronaphthalenone from the endophytic fungus Nodulisporium sp. of Antidesma ghaesembilla

Two new dihydronaphthalenones (1, 2) with four known compounds (3–6) were isolated as secondary metabolites of the endophytic fungus Nodulisporium sp. from Antidesma ghaesembilla. Their chemical structures were established based on 1D and 2D NMR spectroscopic data and HR-ESI–MS analyses. The relative configuration of 2 was confirmed by single crystal X-ray crystallographic analysis. A new isofuranonaphthalenone 2 displayed antimycobacterial and antimalarial activities with IC₅₀ values of 3.125 and 11.3 μg/mL, respectively.     

Cytotoxic pterosins from Pteris multifida roots against HCT116 human colon cancer cells

Two new pterosin glycosides, (2S,3S)-pterosin C 3-O-β-d-(4′-(E)-caffeoyl)-glucopyranoside (1) and (2S,3S)-pterosin C 3-O-β-d-(6′-(E)-p-coumaroyl)-glucopyranoside (2), were isolated from Pteris multifida (Pteridaceae) roots along with ten known pterosin compounds (3–12). The chemical structures of the isolated compounds were elucidated by extensive analysis of the 1D, 2D NMR, HRESIMS, and CD spectroscopic data. The cytotoxicities of 1–12 against HCT116 human colorectal cancer cell line were evaluated. Among the isolates, compound 1 showed moderate antiproliferative activity in HCT116 cells with an IC₅₀ value of 8.0 ± 1.7 μM. Additionally, 1 induced the upregulation of the caspase-9 and procaspase-9 levels in Western blots and increased the annexin V/propidium iodide (PI)-positive cell population in flow cytometry.     

Prenylflavone derivatives from Broussonetia papyrifera,inhibit the growth of breast cancer cells in vitro and in vivo

Two new prenylflavones 5,7,3′,4′-tetrahydroxy-3-methoxy-8-geranylflavone (1) and 5,7,3′,4′-tetrahydroxy-3-methoxy-8,5′-diprenylflavone (2), as well as four known ones, uralenol (3), papyriflavonol A (4), broussoflavonol B (5) and broussochalcone A (6) were isolated and purified from an ethyl acetate-soluble extract of the barks of Broussonetia papyrifera. Their structures were determined with the spectroscopic methods including HR-EI-MS, 1D and 2D NMR. We found that compounds 2–6 showed potent anti-proliferation effects on ER-positive breast cancer MCF-7 cells in vitro. The IC₅₀ values of compounds 2 and 5 were 4.41 and 4.19 μM respectively after the treatment of 72 h. We also found that compounds 2 and 5 strongly down-regulated expression concentrations of estrogen receptor-α (ER-α) and were able to inhibit tumor growth in a xenograft model of the human breast cancer line BCAP-37 in vivo. Our results demonstrated that prenylflavones from B. Papyrifera exhibit potent anti-tumor activity.     

Two new rotenoids from the roots of Millettia speciosa

Two new rotenoids, named millettiaosas A–B (1–2), together with four known compounds were isolated from the roots of Millettia speciosa. Their structures were elucidated on the basis of spectroscopic analysis including 1D and 2D NMR techniques and HRESIMS. Evaluation of the two new compounds for cytotoxicity against four human cancer cell lines (MCF-7, HCT-116, A549 and HepG-2) showed moderate activities (10 μM < IC₅₀ < 26 μM).     

Daphnodorin dimers from Edgeworthia chrysantha with α-glucosidase inhibitory activity

Four daphnodorin dimers named herein as edgechrins A–D (1–4) were isolated from the stems and twigs of Edgeworthia chrysantha Lindl. along with four known compounds identified as daphnodorin A (5), B (6), C (7) and I (8). Their structures were established by spectroscopic methods, including IR, HR-MS, and 1D- and 2D NMR. All of these compounds showed potent in vitro α-glucosidase inhibitory activity with IC₅₀ values in the range of 0.4–20 μM.     

Lactarane sesquiterpenoids from Lactarius subvellereus and their cytotoxicity

Subvellerolactones B (1), D (2), and E (3), structurally unusual lactarane sesquiterpenoids, were isolated from the fruiting bodies of Lactarius subvellereus together with four known lactarane sesquiterpenes (4–7). The chemical structures and stereochemistries of compounds 1–3 were determined on the basis of spectroscopic analyses, including 1D and 2D NMR experiments and a convenient Mosher ester procedure. Subvellerolactone B (1) exhibited cytotoxicity against the A549, SK-MEL-2, and HCT-15 cell lines with IC₅₀ values of 26.5, 18.3, and 14.2 μM, respectively, and subvellerolactones D (2) and E (3) showed cytotoxicity against the A549 and HCT-15 cell lines (IC₅₀ (2): 25.1 and 17.8 μM, and IC₅₀ (3): 19.6 and 28.7 μM, respectively).     

Bioactive azaphilones from the fungus Penicillium multicolor CM01

Two new azaphilones, dechloroisochromophilone II (1) and epi-isochromophilone III (2), a new natural product, 5-hydroxy-4-methoxy-5,6-dihydro-2H-pyran-2-one (3), together with eleven known compounds, 4–14 were isolated from the fungus, Penicillium multicolor CM01. Their structures were elucidated by spectroscopic methods. Compounds 2, 8, 10 and 11 exhibited antimalarial activity against Plasmodium falciparum (IC₅₀ 2.1–7.8 μg/mL), while compounds 9 and 10 showed antimycobacterial activity against Mycobacterium tuberculosis (MIC 6.2 and 50.0 μg/mL, respectively). Compounds 2, 4, and 7–11 showed cytotoxicity against three cancer cell lines, KB, MCF-7 and NCI-H187 (IC₅₀ 2.2–35.2 μg/mL). In addition, compounds 1, 5–8 and 11 showed a minimum inhibition requirement to acetylcholinesterase (AChE) assay in the range of 0.03–0.25 nM.     

Acridone alkaloids from Vepris verdoorniana (Excell & Mendonça) Mziray (Rutaceae)

Two new acridone alkaloids, verdoocridone A (1) and B (4), together with fifteen known compounds were isolated from methanol extracts of the roots and leaves of Vepris verdoorniana. The structures of all compounds were determined by comprehensive spectroscopic analyses (1D and 2D NMR, EI- and ESI–MS). The ¹³C NMR values of 1,2,3,5-tetramethoxy-N-methylacridone (2) and 5-methoxyaborinine (3) are also reported. The crude extracts and compounds (1-6) were tested for their antimicrobial activity. The test delivered moderate activities for crude extracts and compounds 1, 5 and 6 against the bacterium Staphylococcus aureus and the fungi Mucor meihei and Candida albicans with MIC values between 115 and 180 μg/mL for extracts and between 21.3 and 29.4 μM for compounds, compared to gentamycin with 0.2 μM and nystatin with 5.2 μM against both fungi. The determination of the radical scanvenging activity using 1,1-dephenyl-2-picrylhydrazyl (DPPH) assay gave moderate antioxidant values for all tested compounds, with IC₅₀ between 0.29 and 0.41 μM, compared to the standard 3-t-butyl-4-hydroxyanisole (BHA) displaying 0.03 μM.     

Bioactive chemical constituents from the root bark of Morus australis

Two new pyranoflavonoids, morustralins A (1) and B (2), a new natural benzene derivative, one benzenoid (Z)-1-hydroxy-4-(2-nitroethenyl)benzene (3), and thirty known compounds were isolated and characterized from the root bark of Morus australis. The structures of the new compounds were established from spectroscopic and spectrometric analyses. Ten isolates (1–10) were examined for inhibitory effects on adenosine diphosphate (ADP)-, arachidonic acid (AA)-, and platelet-aggregating factor (PAF)-induced platelet aggregation. Among the tested compounds, compound 3 displayed the most significant inhibition of ADP- and AA-induced platelet aggregation with IC₅₀ values of 9.76 ± 5.54 and 9.81 ± 2.7 μM, respectively. In addition, eight purified compounds (3–10) were examined for inhibition of nitric oxide (NO) production in RAW 264.7 cells and six compounds (3–8) displayed significant inhibitory effects with IC₅₀ values ranging from 2.1 ± 0.3 to 6.3 ± 0.6 μM.     

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.     

A new phenylpropanoid and an alkylglycoside from Piper retrofractum leaves with their antioxidant and α-glucosidase inhibitory activity

Two new compounds, piperoside (1) and isoheptanol 2(S)-O-β-d-xylopyranosyl (1→6)-O-β-d-glucopyranoside (11), along with 10 known compounds 3,4-dihydroxyallylbenzene (2), 1,2-di-O-β-d-glucopyranosyl-4-allylbenzene (3), tachioside (4), benzyl-O-β-d-glucopyranoside (5), icariside F₂ (6), dihydrovomifoliol-3′-O-β-d-glucopyranoside (7), isopropyl O-β-d-glucopyranoside (8), isopropyl primeveroside (9), n-butyl O-β-d-glucopyranoside (10), isoheptanol 2(S)-O-β-d-apiofuranosyl-(1→6)-O-β-d-glucopyranoside (12), were isolated from the leaves of Piper retrofractum. Their structures were determined from 1D-NMR, 2D-NMR, and HR-ESI-MS spectral, a modified Mosher’s method, and comparisons with previous reports. All of the isolated compounds showed modest α-glucosidase inhibitory (4.60 ± 1.74% to 11.97 ± 3.30%) and antioxidant activities under the tested conditions.     

Phytochemical and cytotoxic studies on the leaves of Calotropis gigantea

A new lignan, 9′-methoxypinoresinol (1), and two new glycosylated 5-hydroxymethylfurfurals, calofurfuralside A (2), and calofurfuralside B (3), together with nine known compounds (4–12) have been isolated from the active fractions, CHCl₃ (IC₅₀, 0.32 μg mL^?1) and EtOAc (IC₅₀, 0.55 μg mL^?1) fractions of the leaves of Calotropis gigantea. Their structures were elucidated based on NMR and MS data. Among the isolated compounds, compounds 1 and 9 exhibited potent cytotoxicity against PANC-1 human pancreatic cancer cell line under the normoglycemic condition with IC₅₀ values of 3.7 and 3.3 μM, respectively. 9′-Methoxypinoresinol (1) significantly inhibited the colony formation of PANC-1 cells in a concentration-dependent manner.     

Constituents of Nelumbo nucifera leaves and their antimalarial and antifungal activity

From the leaves of Nelumbo nucifera (an aquatic plant), one new compound, 24(R)-ethylcholest-6-ene-5α-ol-3-O-β-d-glucopyranoside (1), along with 11 known metabolites (2–12), were isolated and identified by spectroscopic methods including 1D- and 2D NMR. Antifungal activity for (R)-roemerine (3) (IC₅₀/MIC = 4.5/10 μg/mL against Candida albicans) and antimalarial activity for (R)-roemerine (3) and N-methylasimilobine (5) (IC₅₀ = 0.2 and 4.8 μg/mL for the D6 clone, respectively, and 0.4 and 4.8 μg/mL for the W2 clone, respectively) was observed. None of the compounds were cytotoxic to Vero cells up to a concentration of 23.8 μg/mL. NMR data for 10-eicosanol (7) and 7,11,15-trimethyl-2-hexadecanone (10) are presented for the first time. An analysis of the structure–activity relationship shows that the substituents in position C-1 and C-2 of aporphine alkaloids are crucial for the antimalarial activity.     

Steroidal saponins with cytotoxic activity from the rhizomes of Paris polyphylla var. yunnanensis

Two previously unreported spirostanol saponins, dianchonglouosides A and B (1 and 2), along with 7 known steroidal saponins (3–9) were isolated from the rhizomes of Paris polyphylla var. yunnanensis. Their structures were elucidated by extensive spectroscopic analysis (MS, 1D, and 2D NMR), and chemical methods. The cytotoxic activities of the isolated compounds 1–9 were also evaluated against two human cancer cell lines (HEK293 and HepG2). The results showed that compound 7 had the strongest cytotoxic activity against the two cancer cell lines with the IC₅₀ values of 0.6 and 0.9 μM, respectively.     

Phenylethanoid glycosides from the leaves of Magnolia hodgsonii

Three new phenylethanoid glycosides, 2-(3-hydroxy-4-methoxyphenyl)ethyl 1-O-β-d-allopyranoside (hodgsonialloside A, 1), 2-(3-hydroxy-4-methoxyphenyl)ethyl 1-O-β-d-glucopyranosyl-(1 → 4)-β-d-allopyranoside (hodgsonialloside B, 2) and 2-(3-methoxy-4-hydroxyphenyl)ethyl 1-O-β-d-allopyranoside (hodgsonialloside C, 3) were isolated from the leaves of Magnolia hodgsonii in addition to six known compounds, tyrosol 4-O-β-d-xylopyranosyl-(1 → 6)-β-d-glucopyranoside (4), kaempferol 3-O-neohesperidoside (5), kaempferol 3-O-rutinoside (6), kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 2)-[α-l-rhamnopyranosyl-(1 → 6)]-β-d-glucopyranoside (7), (+)-syringaresinol O-β-d-glucopyranoside (8), and oblongionoside C (9). The structure elucidation of these compounds was based on analyses of physical and spectroscopic data including 1D and 2D NMR experiments.     

Chemical constituents from the fruit of Gardenia jasminoides and their inhibitory effects on nitric oxide production

Three new iridoid glycosides, 6″-O-trans-caffeoylgenipin gentiobioside (1), genipin 1-O-β-d-apiofuranosyl (1→6)-β-d-glucopyranoside (2), genipin 1-O-α-d-xylopyranosyl (1→6)-β-d-glucopyranoside (3), three new monocyclic monoterpenoids, jasminoside R (4), jasminoside S (5), jasminoside T (6), together with nine known iridoid glycosides (7–15) and three crocetin glycosides (16–18), were isolated from the fruit of Gardenia jasminoides. Their chemical structures were established mainly by 1D and 2D NMR techniques and mass spectrometry. Inhibitory effects of the isolated compounds on nitric oxide production in lipopolysaccaride-activated macrophages were evaluated. Compounds 8 and 18 showed strong inhibitory activity on NO production with IC₅₀ values of 11.14 ± 0.67 and 5.99 ± 0.54 μM, respectively.     

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.