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.

Components with Anti-Diabetic Activity Isolated from the Leaves and Twigs of Glycosmis pentaphylla Collected in Vietnam

A phytochemical investigation of the leaves and twigs of Glycosmis pentaphylla (Rutaceae), collected in Vietnam, yielded three new compounds named glyfuran (1), glyphyllamide (2), and glyphyllazole (3), along with twenty-five known compounds (4-28). The structures of isolates were determined by IR, MS, NMR, and UV data analyses. In the anti-diabetic activity screening, (+)-isoaltholacton (4), glycoborinine (17), 2',4'-dihydroxy-4,6'-dimethoxychalcone (24), and flavokawain A (25) simultaneously exhibited inhibition of dipeptidyl peptidase-4 (DPP4) and stimulation of the glucagon-like peptide-1 (GLP-1) secretion on the murine intestinal secretin tumor cell line (STC-1).

Phytochemicals Derived from Goniothalamus elegans Ast Exhibit Anticancer Activity by Inhibiting Epidermal Growth Factor Receptor

Cancer is a major health burden and a leading cause of death worldwide, with numerous new molecules being studied and developed as therapeutic agents. In this study, the cytotoxicity of compounds derived from Goniothalamus elegans was evaluated for possible anticancer activity. It was observed that the crude methanol extract of G. elegans exerted the strongest cytotoxic activity against SW-480, AGS, and SK-LU-1 cell lines. In addition, two isolated alkaloids—namely, lysicamine and liriodenine—also showed strong inhibitory ability against similar cancer cell lines. To further investigate the compounds’ mechanism of action, a molecular docking approach was utilized to evaluate the potential of the two candidates to interact with the epidermal growth factor receptor. This assay estimated that lysicamine and liriodenine acquired protein binding affinities of −8.8 and −9.7 kcal/mol, respectively. Finally, the stabilities of the ligand–protein complexes were evaluated using molecular dynamics simulations of 100 ns each.

Rare flavonoids and sesquiterpenoids isolated from the leaves of Goniothalamus gracilipes

Three previously undescribed benzopyranyl sesquiterpenes gracilipins BD (1-3) and two flavonoids 5,4'-dihydroxy-6-(2-hydroxybenzyl)-3,7,3'-trimethoxyflavone (4), and 5,4'-dihydroxy-8-(2-hydroxybenzyl)-3,7-dimethoxyflavone (5) were isolated from the leaves of Goniothalamus gracilipes (Annonaceae). Their structures were determined by analyses of MS and 2D NMR data. The absolute configurations of 1 were established by analysis of X-ray diffraction data. Cytotoxic evaluation of the compounds 1-5 against four cancer cell lines (KB, LU-1, HepG-2 and MCF-7) indicated that compound 5 had inhibitory activity against HepG-2 cell line with IC₅₀ value of 16.7 μM. All new compounds (1-5) were evaluated for their antimicrobial activity against a panel of clinically significant microorganisms. Compound 2 showed significant antimicrobial effect on Staphylococus aureus with MIC value of 32 μg/mL.

Diastereoselective Construction of trans-2-Alkyl-6-aryl-3,6-dihydro-2H-pyrans via Dehydrogenative Cycloetherification Promoted by DDQ

A diastereoselective synthesis of trans-2-alkyl-6-aryl-3,6-dihydro-2H-pyrans has been described. Dehydrogenative cycloetherification of (E)-(±)-1-aryl-5-hydroxy-1-alkenes promoted by DDQ proceeded cleanly via 6-endo cyclization to afford trans-2-alkyl-6-aryl-3,6-dihydro-2H-pyrans (32 examples) in good yield (up to 89%) and with moderate to excellent diastereoselectivity (up to 99:1). The synthetic utility of the method was illustrated by the second total synthesis of (±)-(2R,6S)-3,4-dehydro-1,7-bis(4-hydroxy phenyl)-4'-de-O-methyl centrolobine and a total synthesis of (±)-centrolobine.

Goniolanceolatins A-H, Cytotoxic Bis-styryllactones from Goniothalamus lanceolatus

Eight new bis-styryllactones, goniolanceolatins A-H (1-8), possessing a rare α,β-unsaturated δ-lactone moiety with a (6S)-configuration, were isolated from the CH₂Cl₂ extract of the stembark and roots of Goniothalamus lanceolatus Miq., a plant endemic to Malaysia. Absolute structures were established through extensive 1D- and 2D-NMR data analysis, in combination with electronic dichroism (ECD) data. All of the isolates were evaluated for their cytotoxicity against human lung and colorectal cancer cell lines. Compounds 2 and 4 showed cytotoxicity, with IC₅₀ values ranging from 2.3 to 4.2 μM, and were inactive toward human noncancerous lung and colorectal cells. Compounds 1, 3, 6, 7, and 8 showed moderate to weak cytotoxicity. Docking studies of compounds 2 and 4 showed that they bind with EGFR tyrosine kinase and cyclin-dependent kinase 2 through hydrogen bonding interactions with the important amino acids, including Lys721, Met769, Asn818, Arg157, Ile10, and Glu12.

Styryl Lactones from Roots and Barks Goniothalamus lanceolatus

A new styryl lactone, 5 R,6 R-5-hydroxy-6-styryltetrahydropyrane-2-one 2 was isolated from the roots of an endemic Goniothalamus lanceolatus Miq. of Sarawak, Malaysia. Furthermore, seven previously undescribed diastereomers, 5 R,6 R-5-hydroxygoniothalamin 3, 5 R,6 R-5-acetylgoniothalamin 4, 6 S,7 S,8 S-goniodiol-7-monoacetate 5, 6 S,7 S,8 S-goniodiol-8-monoacetate 6, goniofupyrone B 7, deoxygoniopypyrone B 8 and 1 S,5 S,7 R,8 S,3- endo,7- endo-(+)-8- epi-9-deoxygoniopypyrone acetate 9, along with six known styryl lactones (1, 10–15) were also isolated and characterized. 6 S-goniothalamin 1 is reported for the first time from a Goniothalamus species. 1, 11 and 12 showed cytotoxic activity against human colon and lung cancer cell lines with IC50 values ranging from 2.38–7.59 μM.

Goniothalamin-Related Styryl Lactones: Isolation, Synthesis, Biological Activity and Mode of Action

This review covers the chemistry and biological aspects of goniothalamin-related styryl lactones isolated from natural sources. This family of secondary metabolites has been reported to display diverse uses in folk medicine, but only a limited number of these compounds have been throughly investigated regarding their biological profile. Herein, we cover the goniothalamin-related styryl lactones having a C6-C3-C4 framework which appeared in the literature for the first time in the period 2000-2017, and the reports on the synthesis, biological activity and mechanism of action which were published from 2007-2017.

New Compounds and Potential Candidates for Drug Discovery from Medicinal Plants of Vietnam

The study of natural products introduces interesting new bioorganic structures and potential candidates for the drug discovery stage in the development of innovative drugs. Vietnam enjoys a broad biodiversity of native plant species, microorganisms, marine organisms, and a long tradition of using herbal remedies. Thus, the study of medicinal plants in determining the basis of their efficacy and safety is an important task for modern researchers in Vietnam. The present review covers literature on new compounds elucidated from the systematic study of medicinal plants within some popular genera in Vietnam, as well as their significant biological activities.

In vivo Antiplasmodial and Toxicological Effects of Goniothalamus lanceolatus Crude Extracts

This study is aimed at investigating the antiplasmodial activity and acute toxicity of the methanol (MeOH) extracts of the leaves and roots, and the dichloromethane (DCM) extracts of the stem bark, leaves, and roots of Goniothalamus lanceolatus. Phytochemical analysis was then carried out on the most active extract. In vivo antiplasmodial activity was assessed using the 4-day suppressive test against Plasmodium berghei ANKA (PbANKA) in mice. The plant extracts were administered intraperitoneally (i.p.) as a single dose (30 mg/kg) starting 4 h after infection. At a dose level of 30 mg/kg (i.p.), the DCM extracts of the stem bark and leaves, and the MeOH root extracts, prolonged the survival period of infected mice compared to that of the negative control. In addition, all crude extracts, except for the DCM root extract, exhibited parasitemia suppressive activity. The highest level of parasitemia suppression was recorded in mice treated with the DCM stem bark extract at 66.3%. No mortality was observed in mice treated with the DCM extracts of the stem bark and leaves, and the MeOH extract of the leaves, indicating that the LD50 is greater than 300 mg/kg. On the other hand, both the MeOH and DCM extracts of the roots showed toxic effects at a dose of 300 mg/kg (i.p) with an 83.3% mortality rate. The results obtained indicate that the stem bark of G. lanceolatus (DCM crude extract) possesses good antiplasmodial activity against PbANKA infected mice without causing acute toxicity. Five known styrylpyrone derivatives namely goniodiol 1, 8-epi-9-deoxygoniopypyrone 2, 9-deoxygoniopypyrone 3, digoniodiol 4 and goniothalamin 5 have been isolated from the bark of Goniothalamus lanceolatus (DCM crude extract). The structures and stereochemistry of all compounds were elucidated by interpretation of spectroscopic data. This study provides a scientific basis to support the traditional use of the plant as a remedy for malaria.

Bioactive 6S-styryllactone constituents of Polyalthia parviflora

Parvistones A-E (1-5), five new styryllactones possessing a rare α,β-lactone moiety and a 6S configuration, were isolated from a methanolic extract of Polyalthia parviflora leaves. The structures and the absolute configuration of the isolates were elucidated using NMR spectroscopy, specific rotation, circular dichroism, and X-ray single-crystal analysis. Compounds 8, 9, 11, and 12 were isolated for the first time. The results were supported by comparing the data measured to those of 6R-styryllactones. Moreover, a plausible biogenetic pathway of the isolated compounds was proposed. The structure-activity relationship of the compounds in an in vitro anti-inflammatory assay revealed the 6S-styryllactones to be more potent than the 6R derivatives. However, the effect was opposite regarding their cytotoxic activity. In addition, 6S-styrylpyrones isolated showed more potent anti-inflammatory and cytotoxic activity when compared to the 1S-phenylpyranopyrones obtained.

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.

A comparative analysis of essential oils of Goniothalamus macrocalyx Ban., Goniothalamus albiflorus Ban. and Goniothalamus tamirensis Pierre ex Fin. & Gagnep. from Vietnam

Essential oils hydrodistilled from the leaves and stem barks of Goniothalamus macrocalyx Ban., Goniothalamus albiflorus Ban. and Goniothalamus tamirensis Pierre ex Fin. & Gagnep. growing in Vietnam were analysed by gas chromatography (GC) and GC-coupled with mass spectrometry. α-Pinene (1.7-50.0%), β-pinene (tr-6.8%), β-myrcene (tr-1.5%), (E)-β-ocimene (tr-4.6%), β-caryophyllene (9.9-12.8%), aromadendrene (0.2-6.0%), α-humulene (1.7-6.9%), α-cadinol (1.2-14.5%), δ-cadinene (0.1-10.3%) and n-hexadecanoic acid (0.2-1.9%) were common to the oil samples. α-Pinene (50.0%) was the most abundant single constituent of the leaf oil of G. macrocalyx, whereas the major compounds of the stem were α-cadinol (14.5%), β-caryophyllene (10.3%) and octadecanoic acid (8.2%). Benzoic acid (18.4%), β-caryophyllene (12.4%) and α-pinene (10.3%) were present in the leaf of G. albiflorus, whereas limonene (21.2%), β-caryophyllene (12.8%) and α-phellandrene (9.3%) were identified in the stem. The leaf oil of G. tamirensis was characterised by abundance of α-pinene (33.4%), viridiflorol (18.5%) and β-caryophyllene (12.4%), whereas γ-gurjunene (11.2%), β-caryophyllene (10.9%) and δ-cadinene (10.3%) predominates in the stem oil.

Diarylheptanoids and flavonoids from viscum album inhibit LPS-stimulated production of pro-inflammatory cytokines in bone marrow-derived dendritic cells

Three new diarylheptanoids, (3S,5R)-3-hydroxy-5-methoxy-1,7-bis(4-hydroxyphenyl)-6E-heptene (1), (3S,5S)-3-hydroxy-5-methoxy-1,7-bis(4-hydroxyphenyl)-6E-heptene (2), and (3S)-3-hydroxy-1,7-bis(4-hydroxyphenyl)-6E-hepten-5-one (3), four new flavonoid glycosides, 3,7,3'-tri-O-methylquercetin-4'-O-β-d-apiofuranosyl-(1→2)-O-β-d-glucopyranoside (4), 7,3'-di-O-methylquercetin-4'-O-β-d-glucopyranosyl-3-O-[6‴-(3-hydroxy-3-methylglutaroyl)]-α-d-glucopyranoside (5), 7,3'-di-O-methylquercetin-4'-O-β-d-glucopyranosyl-3-O-[(6'''''→5'''')-O-1'''''-(sinap-4-yl)-β-d-glucopyranosyl-6‴-(3-hydroxy-3-methylglutaroyl)]-α-d-glucopyranoside (6), and (2S)-5-hydroxy-7,3'-dimethoxyflavanone-4'-O-β-d-apiofuranosyl-(1→5)-O-β-d-apiofuranosyl-(1→2)-O-β-d-glucopyranoside (9), and 17 known compounds were isolated from the leaves and twigs of Viscum album. Compounds 1, 4, and 19 significantly inhibited LPS-stimulated production of TNF-α, IL-6, and IL-12p40 with IC50 values ranging from 0.09 ± 0.01 to 8.96 ± 0.45 μM. (+)-Medioresinol (13) showed inhibitory effects on LPS-stimulated production of IL-12p40 with an IC50 value of 2.00 ± 0.15 μM.

Phenolic compounds from Caesalpinia sappan heartwood and their anti-inflammatory activity

Four new phenolic compounds, caesalpiniaphenols A-D (1-4), together with eight known compounds were isolated from Caesalpinia sappan heartwood. The chemical structures were established mainly by NMR, MS, ECD, and Mosher's method. Compounds 4, 5, and 7 showed weak inhibitory activity against the LPS-induced NO production in macrophage RAW264.7 cells with IC(50) values of 12.2, 3.5, and 5.7 μM, respectively.

Cytotoxic and antioxidant compounds from the stem bark of Goniothalamus tapisoides Mat Salleh

Eleven compounds:goniomicin A (1), goniomicin B (2), goniomicin C (3), goniomicin D (4), tapisoidin (5), goniothalamin (6), 9-deoxygoniopypyrone (7), pterodondiol (8), liriodenine (9), benzamide (10) and cinnamic acid (11), were isolated from the stem bark of Goniothalamus tapisoides. All compounds were identified by spectroscopic analysis and, for known compounds, by comparison with published data. Goniothalamin (6) exhibited mild cytotoxic activity towards a colon cancer cell line (HT-29), with an IC(50)value of 64.17 ± 5.60 µM. Goniomicin B (2) give the highest antioxidant activity in the DPPH assay among all compounds tested, with an IC(50) of 0.207 µM.