Siamfuranones A-C, three novel furanone derivatives from the flowers of Uvaria siamensis and their biological activities

Three previously undescribed furanone derivatives named siamfuranones A-C (1-3), together with 11 known compounds (4-14), were isolated from the flowers of Uvaria siamensis. Their planar structures were determined through analysis of spectrometric and spectroscopic evidence, while electronic circular dichroism (ECD) calculations were used to determine their absolute configurations. In addition, gauge-including atomic orbitals (GIAO) NMR chemical shift calculation, supported by the advanced statistical method DP4 plus, was used to confirm the relative configuration of siamfuranone B (2). All the isolated compounds were evaluated against two cancer cell lines (A549 and Hela), and screened for antibacterial activities. Furthermore, they were assessed for cytotoxicity against a normal cell line (Vero cell).

Anti-proliferative Effects of Pinocembrin Isolated From Anomianthus dulcis on Hepatocellular Carcinoma Cells

BACKGROUND

Hepatocellular carcinoma (HCC) is the most prevalent primary liver cancer. Anomianthus dulcis (Dunal) J.Sinclair (syn. Uvaria dulcis) has been used in Thai traditional medicine in various therapeutic indications. Phytochemical constituents of A. dulcis have been isolated and identified. However, their effects on liver cancer and the associated mechanisms have not been elucidated.

METHODS

Dry flowers of A. dulcis were extracted using organic solvents, and chromatographic methods were used to purify the secondary metabolites. The chemical structures of the pure compounds were elucidated by analysis of spectroscopic data. Cytotoxicity against HCC cells was examined using SRB assay, and the effects on cell proliferation were determined using flow cytometry. The mechanisms underlying HCC inhibition were examined by molecular docking and verified by Western blot analysis.

RESULTS

Among 3 purified flavonoids, pinocembrin, pinostrobin, and chrysin, and 1 indole alkaloid (3-farnesylindole), only pinocembrin showed inhibitory effects on the proliferation of 2 HCC cell lines, HepG2 and Li-7, whereas chrysin showed specific toxicity to HepG2. Pinocembrin was then selected for further study. Flow cytometric analyses revealed that pinocembrin arrested the HCC cell cycle at the G1 phase with a minimal effect on cell death induction. Pinocembrin exerted the suppression of STAT3, as shown by the molecular docking on STAT3 with a better binding affinity than stattic, a known STAT3 inhibitor. Pinocembrin also suppressed STAT3 phosphorylation at both Tyr705 and Ser727. Cell cycle regulatory proteins under the modulation of STAT3, namely cyclin D1, cyclin E, CDK4, and CDK6, are substantially suppressed in their expression levels.

CONCLUSION

Pinocembrin extracted from A. dulcis exerted a significant growth inhibition on HCC cells via suppressing STAT3 signaling pathways and its downstream-regulated genes.

Isopimarane-type diterpenoids from the rhizomes of Kaempferia galanga L. and their biological activities

Fourteen isopimarane diterpenoids (1-14) were isolated from the rhizomes of Kaempferia galanga, including four new compounds (1-4). The isolated secondary metabolites were identified through analysis of spectroscopic (1 D and 2 D NMR) and mass spectrometric data, together with X-ray diffraction studies. Compounds 4-5, 7-11, and 13 showed strong antimalarial activities, with IC₅₀ values in the range of 1.46-3.99 μg/mL. Moreover, compounds 4, 5, 8, and 12 showed cytotoxicity against KB cell line with IC₅₀ values in the range of 6.13-38.2 μg/mL, while compounds 4, 5, and 12 showed cytotoxicity against MCF-7 cell line with IC₅₀ values in the range of 11.75-47.4 μg/mL. Eventually, the isolated compounds were screened against six bacterial strains and Mycobacterium tuberculosis, demonstrating weak to moderate activities.

A new polyphenolic isoprenylated acetophenone dimer from the stem bark of Acronychia pedunculata (L.) Miq

A new acetophenone dimer, 5'-prenylacrovestone (1), together with nineteen known compounds (2-20), were isolated from the stem bark of Acronychia pedunculata (L.) Miq. Their structures were identified by thorough analysis of spectroscopic (IR, 1D and 2D NMR) and mass spectrometric data. The isolated compounds were tested against the bacterial pathogens MRSA, B. cereus, S. aureus and E. coli. Compound 3 demonstrated exceptionally potent antibacterial activity against each of the four strains (MIC values of 1 µg/mL).

Acrotrione B, a Prenylated and Highly Oxidized Xanthenoid with Antibacterial and Anti-proliferative Activities from the Roots of Acronychia pedunculata

A new prenylated xanthenoid with a highly oxidized core, acrotrione B (1: ), together with six previously reported acetophenones (2:  - 7: ), were isolated from the roots of Acronychia pedunculata. The structures of the isolated compounds were elucidated by thorough analysis of their 1D and 2D NMR spectroscopic data. The relative and absolute configurations of acrotrione B were determined by electronic circular dichroism (ECD) calculations. Acrotrione B is an unusual, oxidized xanthenoid with a cyclohexadienone core that has not been previously reported. It thus represents a new skeletal type within the xanthenoid class. Acrotrione B (1: ) exhibited anti-proliferative activity against Hela (IC₅₀ = 16.0 µM) and A549 (IC₅₀ = 16.3 µM) cell lines. 5'-Prenylacrovestone (4: ) and acrovestone (5: ) were even more potent with IC₅₀ values of 5.1 µM and 0.77 µM, respectively, against Hela cells and 11.8 µM and 1.13 µM, respectively, against A549 cells. Moreover, acrotrione B (1: ) displayed moderate antibacterial activities against Staphylococcus aureus, Bacillus cereus, and Bacillus subtilis, with MIC values in the range of 16 - 64 µg/mL. Finally, acropyrone (6: ) showed a significant suppression of lipopolysaccharide (LPS) induced NO production in murine macrophage J774.A1 cells (IC₅₀ = 8.9 µM).

Chemical constituents from the flowers of Anomianthus dulcis (Dunal) J. Sinclair

Phytochemical investigation of the flowers of Anomianthus dulcis led to the isolation of eleven known compounds. The isolated compounds were identified by analysis of physical and spectroscopic (IR, 1 D and 2 D NMR) data. We report five flavonoids (1-4 and 10), two chalcone-sesquiterpenoids (5 and 6), one indole alkaloid (7), one triterpenoid (8), and a mixture of two phenolic compounds (9 and 11). Remarkably, it is the second isolation of sumadain A (5) and sumadain B (6) from a natural source. Compounds 5 and 6 were evaluated against several cancer cell lines, as the previous report lacked biological activity studies. Compound 6 showed strong cytotoxicity against Hela, HT-29, HCT-116, and A549 cell lines, with IC₅₀ values in the range of 5.43-14.64 µg/mL.

Assessment of antimycobacterial activities of pure compounds extracted from Thai medicinal plants against clarithromycin-resistant Mycobacterium abscessus

Background

Infection with Mycobacterium abscessus is usually chronic and is associated with clarithromycin resistance. Increasing drug resistance is a major public-health problem and has led to the search for new antimycobacterial agents. We evaluated the antimycobacterial activity, toxicity, and synergistic effects of several plant secondary metabolites against M. abscessus.

Methods

Twenty-three compounds were evaluated for antimycobacterial activity against thirty M. abscessus clinical isolates by broth microdilution to determine their minimum inhibitory concentration (MIC) values. Toxicity was evaluated using red and white blood cells (RBCs and WBCs). The compounds were used in combination with clarithromycin to investigate the possibility of synergistic activity.

Results

Five out of twenty-three compounds (RL008, RL009, RL011, RL012 and RL013) exhibited interesting antimycobacterial activity against M. abscessus, with MIC values ranging from <1 to >128 μg/mL. These extracts did not induce hemolytic effect on RBCs and displayed low toxicity against WBCs. The five least-toxic compounds were tested for synergism with clarithromycin against seven isolates with inducible clarithromycin resistance and seven with acquired clarithromycin resistance. The best synergistic results against these isolates were observed for RL008 and RL009 (8/14 isolates; 57%).

Conclusions

This study demonstrated antimycobacterial and synergistic activities of pure compounds extracted from medicinal plants against clarithromycin-resistant M. abscessus. This synergistic action, together with clarithromycin, may be effective for treating infections and should be further studied for the development of novel antimicrobial agents.

Acroflavone A, a new prenylated flavone from the fruit of Acronychia pedunculata (L.) Miq

Phytochemical investigation of the fruit of Acronychia pedunculata (L.) Miq. led to the isolation of a new prenylated flavone, acroflavone A (1), together with eight known compounds (2-9). Their structures were elucidated by thorough analysis of mass spectrometric and NMR spectroscopic data. The isolated compounds were evaluated against several bacterial strains. Three known compounds (3-5) demonstrated antibacterial activities. Among them, acrovestone (5) proved equally or more potent than chloramphenicol against three out of the four strains tested.

Acroquinolones A and B, two polyphenolic isoprenylated acetophenone-quinolone hybrids with anti-proliferative activities from Acronychia pedunculata (L.) Miq

Two new compounds belonging to a new class of acetophenone-alkaloid hybrids, acroquinolones A (1a) and B (1b), together with six known compounds, were isolated from the leaves of Acronychia pedunculata (L.) Miq. Their structures contain a quinolone and an acetophenone fragment, connected through an isopentyl unit. Attempts to isolate more hybrids from another sample collected at the same location but during a different season led to the isolation of a new tocopherol (2). The new compounds were evaluated against several cancer cell lines.

New iridoid glucosides from the roots of Rothmannia wittii (Craib) Bremek

Phytochemical investigation of the roots of Rothmannia wittii led to the isolation of three new iridoid glucosides, named rothmanniosides A-C (1-3), and nine known compounds (4-12). Their structures, including their absolute configurations, were elucidated by thorough analysis of mass spectrometric and NMR spectroscopic data, together with CD calculations. Compounds 4 and 11 are reported from the Rubiaceae family for the first time.

Promising Anticancer Effect of Aurisin A Against the Human Lung Cancer A549 Cell Line

Objective:

To investigate the anticancer effect of aurisin A and the underlying mechanisms of its action on the human lung cancer A549 cell line.

Methods:

Cell viability was determined by sulforhodamine B (SRB) assay, while cell cycle distribution and apoptosis were measured by flow cytometry. The molecular underlying mechanisms of anti-cancer properties of aurisin A was determined by western blot analysis.

Results:

Aurisin A exerts its anticancer effects by inhibiting cell growth (p<0.001), increasing the proportion of cells at the G0/G1 phase (p<0.001), and decreasing the expression of cyclin D (p<0.05) and cyclin-dependent kinase 4 (Cdk-4) (p<0.001). Nuclear morphological changes were observed in aurisin A-treated cells, demonstrated by a dose-dependent increase in the number of apoptosis cells (p<0.001). After aurisin A treatment, B-cell lymphoma 2 (Bcl-2) was down-regulated (p<0.05), cleaved caspase-3 was up-regulated (p<0.05). In addition, aurisin A inhibits migration of cancer cells in a dose-dependent manner (p<0.001) and decreases the expression of epidermal growth factor receptor (EGFR) (p<0.05) and phosphorylated p38 (pp38) (p<0.05).

Conclusion:

These results indicated that in-vitro treatment of aurisin A against this human lung cancer cell line inhibits cell proliferation and migration, and induces apoptosis and cell-cycle arrest. Aurisin A is a promising anticancer agent for use against human lung cancer.

New anthracene and anthraquinone metabolites from Prismatomeris filamentosa and their antibacterial activities

An unusual, new anthracene natural product named filamentos A (1), two new anthraquinone derivatives named filamentos B (2) and C (3), together with sixteen known compounds (4-19), were isolated from the roots of the tree Prismatomeris filamentosa. Their structures were identified by analysis of mass and spectroscopic data (IR, 1D and 2D NMR). Twelve metabolites (1-6, 9, 12-14, 16-17) showed moderate antibacterial activities against a wide range of Gram-positive and Gram-negative bacteria such as B. subtilis, B. cereus, S. aureus, E. coli, P. aeruginosa and S. sonnei.

New p-terphenyl and benzoquinone metabolites from the bioluminescent mushroom Neonothopanus nambi

Two new p-terphenyls, neonambiterphenyls A and B (1-2), a new benzoquinone, neonambiquinone A (3), together with six known sesquiterpenes (4-9), were isolated from the bioluminescent mushroom Neonothopanus nambi PW3. The isolated compounds were identified by mass, IR and spectroscopic analyses (1D and 2D NMR). Compounds 1-3 and 5-7 showed cytotoxicity against cancer cell lines such as KB, NCI-H187 and MCF-7 with IC₅₀ values ranging from 1.45 to 49.31 µg/mL. In addition, compounds 1 and 5 showed cytotoxicity against Vero cells with IC₅₀ values of 38.72 and 32.90 µg/mL, respectively.

Two new bioactive triterpenoids from the roots of Colubrina asiatica

Two new ceanothane triterpenes, 3,7-O,O-dibenzoyl ceanothic acid methylester (1) and 3-O-acetyl-7-O-benzoyl ceanothic acid methylester (2), along with nine known compounds (3-11), were isolated from the roots of Colubrina asiatica. The isolated compounds were identified by spectroscopic evidence. Compounds 1 and 2 showed antimalarial activity against Plasmodium falciparum with IC₅₀ values of 4.67 and 3.07 µg/mL, respectively. Compound 2 also showed antimycobacterial activity against Mycobacterium tuberculosis (MIC 6.25 µg/mL). In addition, compounds 1, 2, 10 and 11 showed cytotoxicity against three cancer cell lines (KB, NCI-H187 and MCF-7) with IC₅₀ values ranging from 8.32 to 46.72 µg/mL.

Secondary Metabolites and Their Biological Activity from Aspergillus aculeatus KKU-CT2

The bioactive compounds of the fungus Aspergillus aculeatus strain KKU-CT2, have been studied. The crude extracts from this fungus showed good antimicrobial activity against human pathogens, including Gram-positive and Gram-negative bacteria and yeast-like fungi. Its chemical components were isolated and purified by chromatographic methods. The structures of the secondary metabolites were elucidated by spectroscopic methods (IR, ¹H, and ¹³C NMR). They were identified as ergosterol peroxide (1), secalonic acid D (2), secalonic acid F (3), variecolin (4), variecolactone (5), and ergosterol (6). Compounds 1 and 4-6 are reported for the first time as fungal metabolites from this species. Compound 1 displayed inhibitory effects on HSV-1 with an IC₅₀ of 11.01 μg/ml. Compounds 3, 4, and 6 exhibited antimalarial activity against Plasmodium falciparum with IC₅₀ of 1.03, 1.47, and 5.31 µg/ml, respectively. Additionally, all compounds from A. aculeatus KKU-CT2 showed unprecedented anticancer activities against human epidermoid carcinoma in the mouth (KB) (compounds 1-6), human breast cancer (MCF-7) (compounds 2, 4, and 5), and human lung cancer cells (NCI-H187) (compounds 1-4 and 6). These results suggest that secondary metabolites from A. aculeatus KKU-CT2 might be interesting for further derivatization, targeting diseases such as cancer.

Gold Nanoparticles Enhance the Anticancer Activity of Gallic Acid against Cholangiocarcinoma Cell Lines

Gold nanoparticles (GNPs) were conjugated with gallic acid (GA) at various concentrations between 30 and 150 μM and characterized using transmission electron microscopy (TEM) and UV-Vis spectroscopy (UV-VIS). The anticancer activities of the gallic acid-stabilized gold nanoparticles against well-differentiated (M213) and moderately differentiated (M214) adenocarcinomas were then determined using a neutral red assay. The GA mechanism of action was evaluated using Fourier transform infrared (FTIR) microspectroscopy. Distinctive features of the FTIR spectra between the control and GA-treated cells were confirmed by principal component analysis (PCA). The surface plasmon resonance spectra of the GNPs had a maximum absorption at 520 nm, whereas GNPs-GA shifted the maximum absorption values. In an in vitro study, the complexed GNPs-GA had an increased ability to inhibit the proliferation of cancer cells that was statistically significant (P<0.0001) in both M213 and M214 cells compared to GA alone, indicating that the anticancer activity of GA can be improved by conjugation with GNPs. Moreover, PCA revealed that exposure of the tested cells to GA resulted in significant changes in their cell membrane lipids and fatty acids, which may enhance the efficacy of this anticancer activity regarding apoptosis pathways.

Bioactive diterpenes from the aerial parts of Anisochilus harmandii

Two new diterpenes, 4- EPI-triptobenzene L ( 1) and 12- O-deacetyl-6- O-acetyl-19- acetyloxycoleon Q ( 2), as well as eight known diterpenes ( 3- 10) were isolated from the aerial parts of Anisochilus hamandii. Structures of the isolated compounds were identified from spectroscopic evidence. Compounds 1, 2, 5, and 10 exhibited antiplasmodial activity against Plasmodium falciparum (IC (50) 4.70, 2.90, 3.03, and 7.20 microg/mL, respectively), while 3, 5, and 7 showed antimycobacterial activity against Mycobacterium tuberculosis (MIC 50 microg/mL). In addition, only 10 showed strong cytotoxicity against NCI-H187 cells (IC (50) 4.43 microg/mL).

Bioactive styryllactones and alkaloid from flowers of Goniothalamus laoticus

ETHNOPHARMACOLOGICAL RELEVANCE

Goniothalamus laoticus (Annonaceae) is being used traditionally as a tonic and a febrifuge by the local people in the northeastern part of Thailand.

AIM OF STUDY

To investigate the Thai medicinal plant, Goniothalamus laoticus, for antiplasmodial, antimycobacterial and cytotoxicity activities.

MATERIALS AND METHODS

The flowers extracts of Goniothalamus laoticus were isolated by chromatographic techniques. Structures of isolated compounds were identified by spectroscopic methods. The antiplasmodial, antimycobacterial and cytotoxicity evaluation of styryllactone derivatives and alkaloid were also performed.

RESULTS

Ten compounds, cinnamic acid (1); dihydrochrysine (2); beta-sitosterol (3); six styryllactones, (+)-3-acetylaltholactone (4), goniotriol (5), (+)-altholactone (6), (+)-goniofufurone (7), 9-deoxygoniopypyrone (8), howiinin A (9); and an aporphine alkaloid; (-)-nordicentrine (10) were isolated from flowers of Goniothalamus laoticus. Among these, compounds 1, 3-5, 8-10 are first isolated from the Goniothalamus laoticus. Besides, compound 10 is the first report from the Goniothalamus genus. The isolated compounds were evaluated in antiplasmodial, antimycobacterial and anticancer cell lines tests. Compounds 4-6 and 10 exhibited antiplasmodial activity against Plasmodium falciparum (IC(50) 2.6, 7.9, 2.6 and 0.3 microg/mL, respectively), while 5, 6, 9 and 10 showed antimycobacterial activity against Mycobacterium tuberculosis (MIC 100, 6.25, 6.25 and 12.5 microg/mL, respectively). In addition, compounds 4-10 showed cytotoxicity against cancer cells, KB, BC1, NCI-H187, and MCF-7 with IC(50) ranging from 0.4 to 22.7 microg/mL.

CONCLUSION

This finding showed that the styryllactone derivatives and alkaloid isolated from the flowers of Goniothalamus laoticus exhibited antiplasmodial activity against Plasmodium falciparum, antimycobacterail against Mycobacterium tuberculosis and cytotoxicity against four cancer cell lines.

Bioactive constituents of the roots of Polyalthia cerasoides

A new dimeric aporphine alkaloid, bidebiline E (1), and a new natural product, octadeca-9,11,13-triynoic acid (2), along with three known sesquiterpenes, alpha-humulene (3), caryophyllene oxide (4), and (-)-alpha-cadinol (5), and four known isoquinoline alkaloids, laudanosine (6), codamine (7), laudanidine (8), and reticuline (9), were isolated from the roots of Polyalthia cerasoides. The structures of compounds 1 and 2 were established on the basis of their 1D and 2D NMR spectroscopic data. Among these isolates, 1, 2, 4, 7, and 8 exhibited antimalarial activity against Plasmodium falciparum, while 1- 3 showed antimycobacterial activity against Mycobacterium tuberculosis using in vitro assays.