Larvicidal Activity of MalaysianGoniothalamusSpecies

Isolation, Structure Elucidation and in Vitro Anticancer Activity of Phytochemical Constituents of Goniothalamus wynaadensis Bedd. and Identification of α-Tubulin as a Putative Molecular Target by in Silico Study

The phytochemical analysis of ethyl acetate and methanol extract of Goniothalamus wynaadensis Bedd. leaves led to an isolation of eight (1-8) known molecules, among them seven (2-8) isolated for the first time from this species, which includes (+)-goniothalamin oxide (2), goniodiol-7-monoacetate (3), goniodiol-8-monoacetate (4), goniodiol (5), (+)-8-epi-9-deoxygoniopypyrone (6) etc. The phytochemical modification by acetylation of 3 and 4 gave goniodiol diacetate (9) with absolute configuration (6R, 7R, 8R) confirmed by single crystal X-ray diffraction. Compounds 3-9 were cytotoxic against breast, ovarian, prostate and colon cancer cell lines with IC50 <10 μM. Cell cycle analysis and Annexin-V assay on MDA-MB-231 cell using goniodiol-7-monoacetate (3) exhibited apoptotic response as well as necrotic response and showed cell proliferation arrest at G2/M phase. An in silico target identification for these molecules was carried out with an α-tubulin protein target by covalent docking. To gain an in-depth understanding and identify the stability of these protein-ligand complexes on thermodynamic energy levels, further assessment of the isolated molecules binding to the Cys-316 of α-tubulin was performed based on reaction energetic analysis via DFT studies which hinted the isolated molecules may be α-tubulin inhibitors similar to Pironetin. Molecular dynamics reiterated the observations.

Alkaloids and Styryl lactones from Goniothalamus ridleyi King and Their α-Glucosidase Inhibitory Activity

Gonioridleylactam (1), a new compound, is a unique dimeric aristolactam isolated from the EtOAc extract of the twigs of Goniothalamus ridleyi King. The structure of gonioridleylactam (1) consists of two different aristolactams linked together with two methylenedioxy bridges at C-3/C-3' and C-4/C-4', generating a ten-membered ring of [1,3,6,8]tetraoxecine. A new natural product, gonioridleyindole (3-hydroxymethyl-1-methyl-1H-benz[f]indole-4,9-dione, 2), together with eight known compounds (3-10) were also isolated from this plant. Their structures were extensively characterized by spectroscopic methods and comparisons were made with the literature. Compounds 1-4, 7, and 9 were evaluated for their α-glucosidase inhibitory activity. Of these, 3,5-demethoxypiperolide (7) displayed the highest α-glucosidase inhibitory activity, with an IC₅₀ value of 1.25 µM.

Antiproliferative effect of alkaloids via cell cycle arrest from Pseuduvaria rugosa

CONTEXT

Pseuduvaria rugosa (Blume) Merr. (Annonacaea) grows widely in the south and southeast regions of Thailand. Preliminary screening for biological activities revealed that crude hexane, ethyl acetate, and acetone extracts from mixtures of leaves and twigs of P. rugosa showed cytotoxicity.

OBJECTIVE

Chemical constituents and their antiproliferative activity in K562, U937, and HL-60 human leukemic cell lines from P. rugosa were performed for the first time.

MATERIALS AND METHODS

The isolated compounds were obtained from chromatographic separation. The structures were established by spectroscopic techniques including IR, UV, NMR together with 2D NMR (HMBC, COSY, and NOE) and MS. The K562, U937, and HL-60 cell lines were treated with isolated aporphine alkaloids (0-100 µg/mL) and cell viability was measured with the MTT assay. Cell cycle analysis was performed using propidium iodide (PI) based staining methods.

RESULTS

Two known aporphine alkaloids, 1,2,3-trimethoxy-5-oxonoraporphine (1) and ouregidione (2) were isolated. Treatment of the cells with compounds 1 and 2 at a concentration of 100 µg/mL for 72 h reduced the viability of K562, U937, and HL-60 cell lines to 63 and 64, 38 and 66, and 49 and 64%, respectively. In addition, compounds 1 and 2, at a concentration of 100 µg/mL, exposed to U937 and HL-60 cell lines showed cell cycle arrest. The U937 cell line treated with compounds 1 and 2 increased significantly the proportion of the cell in S phase, whereas the HL-60 cell line-induced G2/M and G1 phase, respectively.

DISCUSSION AND CONCLUSION

The results showed that 1,2,3-trimethoxy-5-oxonoraporphine and ouregidione-induced cytotoxicity with HL-60, U937, and K562 cells where 1,2,3-trimethoxy-5-oxonoraporphine was more active than ouregidione.

Zanthoxoaporphines A-C: Three new larvicidal dibenzo[de,g]quinolin-7-one alkaloids from Zanthoxylum paracanthum (Rutaceae)

The bioassay-guided purification of Zanthoxylum paracanthum (Rutaceae) extracts led to the isolation of three new alkaloids, namely 1-hydroxy-10-methoxy-7H-dibenzo[de,g]quinolin-7-one (zanthoxoaporphine A, 2), 1-hydroxy-7H-dibenzo[de,g]quinolin-7-one (zanthoxoaporphine B, 3) and 1,8-dihydroxy-9-methoxy-7H-dibenzo[de,g]quinolin-7-one (zanthoxaporphine C, 4), and a known lignan identified as sesamin (1). Isolation and purification of the constituent compounds was achieved through conventional chromatographic methods. The chemical structures of the isolated compounds were determined on the basis of UV, IR, NMR and MS data, and confirmed by comparison with those reported in the literature. The larvicidal activity of some of the isolated compounds was investigated by using third-instar Anopheles gambiae larvae.

Acetogenins from Annonaceae: recent progress in isolation, synthesis and mechanisms of action

The aim of the present review is to summarise the knowledge about newly isolated acetogenins (ACGs) in the last six years. It will also report the total syntheses that have allowed either the confirmation or the revision of some structures, together with the biological activities and mechanism of action of such interesting natural products. In fact, of the 417 isolated compounds reviewed, over 176 have been added during the period from 1998 to 2004.