New derivatives of a natural nordentatin

New derivatives were obtained from natural nordentatin (1) previously isolated from the methanol fraction of Clausena excavata by an acylation method. Herein, we report ten new pyranocoumarin derivatives 1a–1j. Their structures were elucidated based on UV-vis, FT-IR, NMR, and DART-MS data. The α-glucosidase inhibition and anticancer activities of nordentatin (1) and its derivatives were also evaluated. The α-glucosidase inhibition assay exhibited that the derivatives 1b, 1d, 1e, 1f, 1h, 1i, and 1j possess higher inhibitory activity for α-glucosidase with IC50 values of 1.54, 9.05, 4.87, 20.25, 12.34, 5.67, and 2.43 mM, whereas acarbose was used as the positive control, IC50 = 7.57 mM. All derivatives exhibited a weak cytotoxicity against a cervical cancer (HeLa) cell line with the IC50 between 0.25 and 1.25 mM. They also showed moderate to low growth inhibition of a breast cancer (T47D) cell line with IC50 values between 0.043 and 1.5 mM, but their activity was lower than that of the parent compound, nordentatin (1) (IC50 = 0.041 mM).

Carbazomarin: A New Potential of α-Glucosidase Inhibitor From Clausena excavata Roots

Continuing our exploration for dual functions antidiabetic and antioxidant agents from Myanmar medicinal plant , a new carbazole-pyranocoumarin conjugate, carbazomarin-C (1) along with a known carbazole alkaloid, mukonine (2) and a pyranocoumarin, xanthoxyletin (3), was isolated from the roots of Clausena excavata. The chemical structures of these compounds were identified using a combination of spectroscopic methods. Among isolates, there was a strong inhibition of compounds (1) and (3) on yeast α-glucosidase in a dose-dependent manner. It was shown when p-nitrophenyl-α-d-glucopyranoside was used as a substrate in vitro with IC50 values 0.22 and 4.81 mM, respectively. However, all isolated compounds displayed no inhibition against DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals.

Carbazole Alkaloids from Clausena anisum-olens: Isolation, Characterization, and Anti-HIV Evaluation

Two new carbazole alkaloids (1,2) and six known carbazole alkaloids (3-8) were isolated from Clausena anisum-olens. Their structures were elucidated based on extensive spectroscopic analysis. All isolated compounds (1-8) were evaluated for their anti-HIV effects on virus replication in MT-4 lymphocytes infected by HIV-1NL4-3 Nanoluc-sec virus, and new carbazole alkaloid 1 exhibited anti-HIV activity with an EC50 value of 2.4 μg/mL and SI of 7.1.

Long-Lasting and Fast-Acting in Vivo Efficacious Antiplasmodial Azepanylcarbazole Amino Alcohol

With ∼429,000 deaths in 2016, malaria remains a major infectious disease where the need to treat the fever symptoms, but also to provide relevant post-treatment prophylaxis, is of major importance. An azepanylcarbazole amino alcohol is disclosed with a long- and fast-acting in vivo antiplasmodial efficacy and meets numerous attributes of a desired post-treatment chemoprophylactic antimalarial agent. The synthesis, the parasitological characterization, and the animal pharmacokinetics and pharmacodynamics of this compound are presented along with a proposed target.

Carbazole-pyranocoumarin conjugate and two carbazole alkaloids from the stems of Clausena excavata

A carbazole-pyranocoumarin conjugate, carbazomarin B (1), and two carbazole alkaloids, 6-methoxymukonidine (2) and 2-hydroxy-3-methoxycarbazole (3), together with 27 known compounds (4-30), were isolated from the stems of Clausena excavata. Their structures have been elucidated by spectroscopic analyses. Compound 2 showed moderate cytotoxicity to HuCCA-1, MOLT-3 and HepG2 cancer cell lines with IC50 values of 15.09-28.50 μg/mL, but none to A549 cell line. Heptaphylline (6) and nordentatin (23) were found to show moderate cytotoxic activity against HepG2 cell line with IC50 values of 12.33 and 11.33, respectively, while clausine K (27) exhibited strong cytotoxicity with IC50 value of 1.05 μg/mL, better than a standard drug (etoposide, IC50 13.40 μg/mL).

The first total synthesis of potent antitumoral (±)-mafaicheenamine A, unnatural 6-fluoromafaicheenamine A and expedient synthesis of clausine E

The first total synthesis of potent antitumoral mafaicheenamine A (1) and its unnatural analogue, 6-fluoromafaicheenamine A (2) have been accomplished.

Vanadium-catalyzed regioselective oxidative coupling of 2-hydroxycarbazoles

The first regioselective oxidative coupling of 2-hydroxycarbazoles is described. With a vanadium catalyst and oxygen as the terminal oxidant, dimers with an ortho-ortho' coupling pattern were obtained with high selectivity. Further oxidation led to ortho'-ortho' coupling to generate a tetramer, which provided insight that the atropisomerization barriers of the unsymmetrical biaryl bonds are much lower than expected.

Palladium(ii)-catalysed total synthesis of naturally occurring pyrano[3,2-a]carbazole and pyrano[2,3-b]carbazole alkaloids

Seven naturally occurring pyranocarbazole alkaloids (pyrayafoline A–E,O-methylmurrayamine A andO-methylmahanine) have been synthesised using a palladium(ii)-catalysed cyclisation of a diarylamine to an orthogonally diprotected 2,7-dihydroxycarbazole as key step.

Identification and optimization of an aminoalcohol-carbazole series with antimalarial properties

Recent observations on the emergence of artemisinin resistant parasites have highlighted the need for new antimalarial treatments. An HTS campaign led to the identification of the 1-(1-aminopropan-2-ol)carbazole analogues as potent hits against Plasmodium falciparum K1 strain. The SAR study and optimization of early ADME and physicochemical properties direct us to the selection of a late lead compound that shows good efficacy when orally administrated in the in vivo P. berghei mouse model.

Clausenawallines G-K, carbazole alkaloids from Clausena wallichii twigs

Five carbazole alkaloids, clausenawallines G-K (1-5), along with 12 known alkaloids (6-17) were isolated from the twigs of Clausena wallichii. Their structures were established using spectroscopic methods and the antibacterial activity of compounds 1-5 was evaluated.

Bioactive carbazole alkaloids from Clausena wallichii roots

Four new carbazole alkaloids, clausenawallines C-F (1-4), along with 18 known compounds (5-22) were isolated from the roots of Clausena wallichii. Compounds 3, 9, and 22 exhibited significant antibacterial activity against methicillin-resistant Staphylococcus aureus SK1 (MRSA SK1) and Staph. aureus TISTR 1466 with MIC values in the range 4-16 μg/mL, whereas compound 4 showed the highest cytotoxicity against oral cavity cancer (KB) and small-cell lung cancer (NCI-H187) with IC(50) values of 10.2 and 4.5 μM, respectively.

A new antifungal coumarin from Clausena excavata

A new γ-lactone coumarin, named as excavarin-A, showing antifungal activity was isolated from the leaves of Clausena excavata by bioassay guided fractionation method. The structure was elucidated by spectroscopic data analysis and identified as 7((2E)-4(4,5-dihydro-3-methylene-2-oxo-5-furanyl)-3-methylbut-2-enyloxy) coumarin. Minimum inhibitory concentration (MIC) was determined against fifteen fungal strains pathogenic against plants and human. The least MIC was recorded against the human pathogen, Candida tropicalis and the plant pathogens Rhizoctonia solani and Sclerotinia sclerotiorum. Antifungal activities against the human pathogens, Aspergillus fumigatus and Mucor circinelloides and plant pathogens, Colletotrichum gloeosporioides, Lasiodiplodia theobromae, Fusarium oxysporum and Rhizopus stolonifer were stronger than that of the standard antimicrobials.

Glycozolidal

The title compound known as glycozolidal (systematic name: 2,7-dimeth­oxy-9H-carbazole-3-carbaldehyde), C₁₅H₁₃NO₃, is a naturally occurring carbazole, which was isolated from the roots of Clausena lansium. The carbazole ring system is essentially planar, with an r.m.s. deviation of 0.0093 (1) Å. In the crystal, inter­molecular N—H⋯O hydrogen bonds connect the mol­ecules into a chain along the c axis. C—H⋯O, C—H⋯π and π–π inter­actions, with centroid–centroid distances of 3.5924 (6), 3.6576 (6) and 3.8613 (6) Å, are also observed.

2-Hy-droxy-7-meth-oxy-9H-carbazole-3-carbaldehyde

The title compound, C(14)H(11)NO(3), was isolated from the roots of Clausena wallichii. The carbazole ring system is approx-imately planar (r.m.s. deviation = 0.039 Å) and the dihedral angle between the two benzene rings is 4.63 (7)°. An intra-molecular O-H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, mol-ecules are linked into a zigzag network extending parallel to the ac plane by O-H⋯N and N-H⋯O hydrogen bonds.

Carbazole alkaloids from the stems of Clausena excavata

A new carbazole alkaloid, sansoakamine (8), together with 11 known compounds, was isolated from the stems of Clausena excavata. All structures were elucidated by spectroscopic methods. Compound 7 showed moderate anti-malarial activity against Plasmodium falciparum with a MIC value of 6.74 microg/ml.