Two new triterpenoid saponins obtained by microbial hydrolysis with Alternaria alternata AS 3.6872

Compound 1, a triterpenoid saponin from Ardisia gigantifolia Stapf showing potential anti-tumour activity, was hydrolysed into two deglycosyl derivatives (2 and 3) by Alternaria alternata AS 3.6872. Both these derivatives are new compounds. Their structures were elucidated on the basis of 1D, 2D NMR, HR-ESI-MS and optical rotation spectral data. Compounds 1–3 were evaluated for their cytotoxicity against human hepatocellular carcinoma and normal liver cells by Cell Counting Kit 8 colorimetric assay.     

A new phenolic glycoside from Saprosma merrillii

A new phenolic glycoside derivative, saproglucoside (1), along with five known phenolic glycoside derivatives (2–6) were isolated from the stems of Saprosma merrillii. The structure of the new compound 1 was determined by 1D and 2D NMR as well as by HRESIMS and hydrolysis. The inhibitory activities of all compounds against seven pathogenic bacteria and two cancer cell lines were evaluated.     

SYNTHESIS OF 5-DODECANOYLAMINE-8-HYDROXY-1,4-NAPHTHOQUINONE AND STUDY OF SOME OF ITS BIVALENT METAL CHELATES

Abstract

Two new naphthoquinone derivatives, 5-dodecanoylamine-8-hydroxy-l,4-naphthoquinone (1) and 5-dodecanoylamine-8-acetoxy-l,4-naphthoquinone (2), have been prepared and characterized. Their chelating ability with Ni(II) and Co(II) have been studied. Compound (1) coordinates to the divalent metal ions as a monoanionic bidentate ligand. The complexes were found to contain two ligands and two molecules of coordinated water. The structure and bonding of the chelates are discussed based on the spectroscopic data.     

A new naphthoquinone analogue and antiviral constituents from the root of Rhinacanthus nasutus

Rhinacanthus nasutus (L.) Kurz (Acanthaceae) is known as traditional medicine for the treatment of fungal and herpes virus infections. A new naphthoquinone racemate, rhinacasutone (1) together with seven known compounds, rhinacanthone (2), rhinacanthins C, D, N, Q, and E (3–7), and heliobuphthalmin (8) were isolated from root of R. nasutus. Their structures were determined on the basis of extensive spectroscopic methods, including 1D-, 2D-NMR and MS data. All the isolated compounds were tested for their antiviral activities against PR8, HRV1B, and CVB3-infected vero cells. Compounds 3–6 exhibited significant antiviral activities with the IC₅₀ value ranging from 0.03 to 23.7 μM in all three infections.     

Two new isoaurones derivatives from Callistephus chinensis flower

Two new isoaurones derivatives were obtained from Callistephus chinensis flower. Their structures were elucidated on the basis of extensive spectroscopic analyses. Both of the new compounds were evaluated cytotoxic activity. Phytochemical investigation of Callistephus chinensis flower led to the isolation of two new isoaurones derivatives (Z)-4′,4,10-trihydroxy-siamaurone (1) and (E)-4′,4,10-trihydroxy-siamaurone (2). The structures of these new compounds were identified by the interpretation of spectroscopic data (mainly 1D and 2D NMR) and by comparison with data reported in the literature. Both of the new compounds were evaluated for their cytotoxicity.     

Two new 2-arylbenzofurnan derivatives from the leaves of Morus alba

Two new 2-arylbenzofuran derivatives, moracinfurol A and B (1–2), and ten known compounds (3–12) were isolated from the leaves of Morus alba. Their structures were determined on the basis of spectroscopic analysis including 1D, 2D NMR and HR-ESI-MS. All of the 2-arylbenzofuran derivatives were evaluated for cytotoxicity against A549 cells. Some cytotoxic 2-arylbenzofuran derivatives might induce autophagy characterized by the accumulation of LC-3 Ⅱ.     

Lactoquinomycin C and D,two new medermycin derivatives from the marine-derived Streptomyces sp. SS17A

Abstract

Lactoquinomycin C (1) and Lactoquinomycin D (2), two new medermycin derivatives together with six known compounds (3–8) were isolated from the rice solid fermentation of the marine-derived Streptomyces sp. SS17A. The intriguing structural features of the Lactoquinomycin D (2) which contains 5,14-epoxidation is relatively rare in medermycin derivatives. Compounds 1 and 2 exhibited no cytotoxicity against PC-3 and HCT-116 cancer cell lines, whereas compound 3 showed stronger cytotoxicity with IC₅₀ values of 0.02 and 0.04?μM, respectively. A structure-activity relationship was observed for the cytotoxicity of the medermycin derivatives with a γ-lactone unit is required for significant cytotoxicity based on compounds 1–3.     

Antimicrobial and antiquorum-sensing activity of Ricinus communis extracts and ricinine derivatives

Ricinine (1), a known major alkaloid in Ricinus communis plant, was used as a starting compound for the synthesis of six ricinine derivatives; two new and four known compounds. The new derivatives; 3-amino-5-methyl-1H-pyrazolo[4,3-c]pyridin-4(5H)-one (2), and 3-amino-5-methyl-1-(phenylsulfonyl)-1H-pyrazolo[4,3-c]pyridin-4(5H)-one (3), as well as the previously prepared derivatives (4–7) were subjected for antimicrobial and antiquorum-sensing evaluation in comparison to different R. communis extracts. Acetyl ricininic acid derivative (5) showed the highest antimicrobial activity among all tested derivatives against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeuroginosa and Candida albicans. However, compound 7 (4-methoxy-1-methyl-2-oxo-1,2-dihydropyridine-3-carboxamide) showed the highest antiquorum-sensing activity among all tested compounds and extracts. These findings proved the usefulness of ricinine as a good scaffold for the synthesis of new antimicrobial and antiquorum-sensing derivatives in spite of its poor contribution to the antimicrobial activity of the plant extracts.     

Pictalignans D-F,three new neolignan derivatives from Selaginella picta

Abstract

Three new neolignan derivatives (1–3), together with three known isolariciresinol derivatives (4–6) were isolated from Selaginella picta. Their structures were elucidated by spectroscopic methods (1D/2D NMR, HRESIMS and CD). All isolated compounds were assayed on the neuroprotective activity against the injury of HT-22 cells induced by L-Glutamate in vitro. All compounds displayed potent protective effect on HT-22 cells.     

A new naphthoquinone and a new neolignan from <Emphasis Type="Italic">Ligularia vellerea</Emphasis> rhizomes

In the course of phytochemical investigations of Ligularia vellerea rhizomes, a new naphthoquinone, 2,5-dihydroxy-6,7-dimethylnaphthoquinone (1), and a new neolignan, 4-[(3',4'-dihydroxycinnamoyl)-oxy]methyl cinnamate (2), have been isolated and characterized on the basis of spectroscopic methods (¹H NMR, ¹³C NMR, 2D NMR, and MS).     

A novel naphthoquinone from <Emphasis Type="Italic">Plumbago zeylanica</Emphasis> roots

A novel naphthoquinone (1) was isolated from the methanol extract of P. zeylanica roots in addition to a known compound plumbagin (2). Their structures were determined by UV, IR, MS, ¹H, and ¹³C NMR spectroscopic analysis, including 2D NMR.     

SYNTHESIS AND STRUCTURE OF 1,2-BIS(DIPHENYLPHOSPHINO)ETHANE COMPLEXES OF COPPER(I) ACETATE. CATALYSTS FOR THE DECARBOXYLATION OF CARBOXYLIC ACIDS

Abstract

Several dimeric complexes of copper(I) acetate with bidentate phosphine ligands have been synthesized. The solid-state structure of one of these derivatives, dppe(CuO₂CCH₃)₂, where dppe = 1,2-bis(diphenylphosphino)ethane, has been determined. The complex is shown to exist in the solid-state as a polymeric chain of dimeric copper(I) units containing a dppe and two acetate ligands, with the dimers being linked together via weaker Cu-O interactions. The Cu-Cu bond length in the dimeric units is considerably longer, at 2.712(2) Å, than that observed in copper(I) acetate of 2.556(2) Å. The use of these derivatives as catalyst precursors for the catalytic decarboxylation of cyanoacetic acid to acetonitrile and carbon dioxide is discussed. Crystal data for dppe(CuO₂CCH₃)₂: space group P2_i/n,a = 14.976(6) Å, b = 11.676(3) Å, c = 16.999(6) Å, β = 107.59(3)°, Z = 4, R = 7.33%     

New naphthopyrones from marine-derived fungus Aspergillus niger 2HL-M-8 and their in vitro antiproliferative activity

A new cytotoxic dimeric naphthopyrone, aurasperone H (1), together with eight related known polyketides (2–9) was isolated from a marine-derived fungus Aspergillus niger 2HL-M-8. The structure of new compound 1 was elucidated on the basis of its spectroscopic data (1D, 2D NMR and CD). Compound 1 exhibited moderate inhibitory activity against the human lung adenocarcinoma A549 and the human leukaemia HL-60 cell lines. Compound 5 displayed significant in vitro antiproliferative activity against HL-60 cell line with an IC₅₀ value of 0.8 μM.     

One-pot,four-component synthesis of benzylpyrazolyl naphthoquinone derivatives and molecular docking studies

A highly efficient, green, one-pot, four-component approach for the synthesis of benzylpyrazolyl naphthoquinone derivatives (5a–p) have been developed by the domino reaction of 2-hydroxy naphthoquinone, aromatic aldehyde, ethyl acetoacetate, and phenyl hydrazine derivatives in water and employed p-toluene sulfonic acid (p-TSA) as the right choice of catalyst at reflux. Docking simulation was performed to position compounds 5a, 5b, and 5g into the anaplastic lymphoma kinase (ALK) structure active site to determine the probable binding model.     

Synthesis and Characterization of Nitrogen and Sulfur Containing 1,4-Naphthoquinones

Abstract

New N,S-disubstituted naphthoquinones were synthesized by reactions of S- and N-nucleophiles with 2,3-dichloro-1,4-naphthoquinone. 2-(Hexadecylthio)-3-(phenylamino)-naphthalene-1,4-dione 5a was synthesized by reaction of 2-chloro-3-(phenylamino)-naphthalene-1,4-dione 3a with hexadecanethiol 4a. The structures of the new synthesized naphthoquinone derivatives were determined by micro analyses and spectroscopic methods (FT-IR, ¹H NMR, ¹³C NMR, MS, and UV/Vis.). Photo- and electrochemical properties of selected compounds were investigated by using fluorescence spectroscopy and the cyclovoltammetry method.     

Polar steroid derivatives from the Vietnamese starfish Astropecten polyacanthus

Five polar steroid derivatives, including one new glycosylated polyhydroxysteroid namely polyacanthoside A (1), were isolated from the water-soluble materials from the MeOH extract of the Vietnamese starfish Astropecten polyacanthus using various chromatographic separations. The structure elucidation was confirmed by spectroscopic experiments such as HR-ESI-MS, 1D and 2D NMR. Among the isolated compounds, (20R,24S)-3β,6α,8,15β,24-pentahydroxy-5α-cholestane (3) showed significant cytotoxic effect against five human cancer cell lines as HepG2, KB, LNCaP, MCF7 and SK-Mel2 with the IC₅₀ values from 18.03 ± 2.63 to 21.59 ± 3.23 μM.     

Two new dammarane-type triterpene sapogenins from Chinese red ginseng

Two new dammarane-type triterpene sapogenins were isolated from the Chinese red ginseng. The new sapogenins were named as 24,26-dihydroxy-panaxdiol (1) and 24-hydroxy-panaxdiol (2). Their structures were elucidated by the combined analysis of NMR and mass spectrometry as 20(S),25(R)-epoxydammarane-3β,12β,24β,26-tetraol (1) and 20(S),25-epoxydammarane-3β,12β,24α-triol (2). The complete signal assignments of the two compounds were carried out by 2D NMR spectral and NOE differential spectroscopy analysis.     

Phytochemical investigations of <Emphasis Type="Italic">Vernonia galamensis</Emphasis> seeds

Vernonia galamensis is a new potential industrial oil seed crop for semiarid areas with very high content of naturally epoxidized vernolic acid (80% of the oil). Chemical investigation of the seeds of Vernonia galamensis afforded two compounds, which are vernolic acid derivatives. Their structures were established by various spectroscopic techniques: IR, UV, NMR, and 2D NMR spectra (COSY, HSQC, and HMBC), and by comparison with literature data for the known compound methylvernolate. The cis-(12S,13R)-(3-methylpentyl) vernolate (1) and the cis-(12S,13R)-(2,3-propanediol) vernolate (2) were isolated and characterized.     

Triterpenoids,megastigmanes and hydroxycinnamic acid derivatives from Anisomeles indica

Six triterpenoids (1–6), four megastigmanes (7–10) and five hydroxycinnamic acid derivatives (11–15) were isolated from the aerial part of Anisomeles indica (Lamiaceae). Of these components, compound 1 was identified to be a new triterpenoid with the structure of 2α,3α,19α-trihydroxyurs-12,20(30)-dien-28-oic acid based on extensive analysis of MS, 1D and 2D NMR spectroscopic data, while compounds 2–13 were obtained for the first time from Anisomeles species.     

Paenibacillin A,a new 2(1H)-pyrazinone ring-containing natural product from the endophytic bacterium Paenibacillus sp. Xy-2

A new 2(1H)-pyrazinone ring-containing natural product, paenibacillin A (1), together with five known diketopiperazine derivatives 2–6 and two known isoflavones 7–8, was isolated from the culture of an endophytic bacterium Paenibacillus sp. Xy-2. The structure of compound 1 was elucidated by extensive spectral methods, including UV, IR, HR-ESI-MS, 1D and 2D NMR and ECD experiments. Compound 1 exhibited moderate cytotoxicity against HL-60 cell line with IC₅₀ value of 50.48 μM.