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).

Antioxidant, Cytotoxic, Anti-Glycation, and Anti-Tyrosinase Compounds from the Leaves of Uvaria Siamensis.

A new oxidized heptene, 7-benzoyloxy-4-hydroxy-1-ethoxy-2E,4Z-heptadiene-1,6-dione, namely siamheptene A (1), together with eight known compounds (2-9), were isolated from the leaves of Uvaria siamensis. Their structures were elucidated by detailed analysis of spectroscopic (IR, 1D and 2D NMR) and mass spectrometric data. Compound 9 is reported for the first time from Uvaria genus. Siamheptene A was evaluated for cytotoxicity against HeLa (cervical cancer cells), A549 (lung cancer cells), and Vero cells using the MTT assay and screened for antibacterial activities. In addition, the isolated compounds (1-7, and 9) were investigated for their antioxidant (DPPH, FRAP and ABTS+ assays), anti-glycation, and anti-tyrosinase properties. Based on our results, compound 1 had mild cytotoxicity against Hela and A549 cancer cell lines, with IC50 ranging from 31.09 to 31.67 µg/mL. Compound 1 also showed antioxidant activities in all tasted assays. However, it showed no detectable activity (>128 µg/mL) against various bacterial strains, and it has no inhibitory effects on tyrosinase enzymes. Among of all tested compounds, chrysin (5), showcased highest anti-glycation and anti-tyrosinase activities. This comprehensive analysis provides highlighting the potential of 1 as a lead compound for further structural modification and development of cytotoxic or antioxidant agents.

Antiphytopathogenic activity of the bioluminescent mushroom Neonothopanus nambi against root-rot disease.

Aurisin A (1) and the culture medium of the luminescent mushroom Neonothopanus nambi showed antifungal activity against Phytophthora palmivora, which causes the root-rot disease of Monthong durian, in a preliminary greenhouse experiment. Moreover, a new natural product, neonambiquinone B (2), was isolated. Their structures were elucidated by mass, IR and extensive analysis of their 1D and 2D NMR spectroscopic data. The results demonstrated that the culture medium of N. nambi is a promising potential for their agricultural applications.

Tocotrienol monomers and dimers from the roots of Litchi chinensis with tyrosinase inhibition activity.

Four undescribed modified tocotrienols, including two monomers, litchinols A (1) and B (2), and two walsurol dimers, δ,δ-walsurol (3) and γ,δ-bi-O-walsurol (4), as well as seven known compounds (5-11) were isolated from the roots of Litchi chinensis. The structures of the undescribed compounds were elucidated based on analyses of spectroscopic data and ECD spectra. All tocotrienol derivatives (1-6) were evaluated for their tyrosinase inhibition activity. Only monomers 1-2 and 5-6 displayed potent inhibitory activity and greater than kojic acid. Kinetic analysis revealed that the representative compound 2 was uncompetitive inhibitor with the inhibition constant value of 5.70 µM.

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).

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.

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).

Fatty acid acylated flavonol glycosides from the seeds of Nephelium lappaceum and their nitric oxide suppression activity.

Five undescribed fatty acid esters of flavonol glycosides, nephelosides A-E, along with eight known compounds, were isolated from the seeds of Nephelium lappaceum L. The structures were elucidated by extensive analysis of spectroscopic data in combination with GC-MS analysis. Potency of compounds toward nitric oxide suppression was assessed by monitoring the inhibition of lipopolysaccharide-stimulated nitric oxide production in J744.A1 macrophage cells. Nepheloside D, kaempferol and kaempferol 7-O-α-L-rhamnopyranoside showed significant activity with IC50 values of 26.5, 11.6 and 12.0 µM, respectively.

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.

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.

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.

Scalarane Sesterterpenoids with Antibacterial and Anti-Proliferative Activities from the Mushroom Neonothopanus nambi.

Seven undescribed scalarane sesterterpenoids, nambiscalaranes B-H (1-7), together with two known compounds, nambiscalarane (8) and aurisin A (9) were isolated from the cultured mycelium of the luminescent mushroom Neonothopanus nambi. Their structures were elucidated by thorough analysis of their 1D and 2D NMR spectroscopic data. The absolute configurations of 1-8 were determined by electronic circular dichroism (ECD) calculations and optical rotation measurements. The isolated sesterterpenoids were evaluated against A549, HT29, HeLa, and HCT-116 cancer cell lines, and against five bacterial strains. Compounds 3, 5, and 7 showed strong cytotoxicity against HCT-116 cell line, with IC50 values ranging from 13.41 to 16.53 µM, and showed no cytotoxicity towards Vero cells. Moreover, compound 8 inhibited the growth of Bacillus subtilis with a MIC value of 8 µg/mL, which was equivalent to the MIC value of the standard kanamycin.

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.

Chemical constituents and their biological activities from the roots of diospyros filipendula.

Phytochemical investigation of Diospyros filipendula (Ebenaceae) resulted in the isolation of eighteen compounds. Their structures were identified by analysis of mass spectrometric and spectroscopic (IR, 1 D and 2 D NMR) data. We report three benzoic acid derivatives (1-3), one peptide (4), one coumarin (5), three phthalides (6-8), three steroids (9-11) and seven triterpenes (12-18). Nine compounds (1, 4-8, 10, 17 and 18) are reported from the Ebenaceae family for the first time while the other nine are new to the species D. filipendula. Compounds 7, 17 and 18 showed low to moderate cytotoxicity against NCI-H187 and Vero cell lines while compound 18 showed moderate cytotoxicity against KB cell line. In addition, compounds 17 and 18 showed moderate to significant antimalarial activity against Plasmodium falciparum.

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.

Spiroaxillarone A, a Symmetric Spirobisnaphthalene with an Original Skeleton from Cyanotis axillaris.

The first representative of a new type of spirobisnaphthalene with a previously unknown skeletal system, Spiroaxillarone A (1), was isolated from Cyanotis axillaris. The planar structure was determined through analysis of spectroscopic evidence, while electronic circular dichroism (ECD) calculations were used to determine its absolute configuration. The structure of 1 was further confirmed through X-ray diffraction studies of its tetrabromobenzoate derivative (1a). Spiroaxillarone A exhibited significant antimalarial activity against resistant Plasmodium falciparum (IC50 = 2.32 µM).

A novel cyclohexenone from Trachyspermum roxburghianum.

A novel cyclohexenone, roxydienone (1), together with 13 known compounds (2-14), were isolated from the seeds of Trachyspermum roxburghianum. The structures of these compounds were established on the basis of their 1D and 2D NMR spectroscopic data. Compounds 1, 2, 7-9 and 14 showed cytotoxicity against NCI-H187 cell line while compounds 1 and 9 showed cytotoxicity against KB cell line. In addition, only compound 13 showed cytotoxicity against MCF-7 cell line.