Tawanun Sripisut

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 μg/ml.

Cowabenzophenones A and B, two new tetracyclo[7.3.3.33,11.03,7]tetradecane-2,12,14-trione derivatives, from ripe fruits of Garcinia cowa

Two new tetracyclo[7.3.3.3(3,11).0(3,7)]tetradecane-2,12,14-trione derivatives, cowabenzophenones A (1) and B (2), were isolated from ripe fruits of Garcinia cowa Roxb. Their structures were determined by spectroscopic methods. The tetracyclo[7.3.3.3(3,11).0(3,7)]tetradecane-2,12,14-trione skeleton from the Garcinia genus is reported for the first time.

Chemical constituents from the roots of Feroniella lucida

A new furanocoumarin named lucidafuranocoumarin A (7) together with 13 known coumarins (1–6, 8–14) and four known alkaloids (15–18) was isolated from the roots of Feroniella lucida. Their structures were elucidated on the basis of spectroscopic analysis. Some of the isolates were evaluated for their biological activities, and compound 18 showed strong cytotoxicity against KB (IC50 = 0.637 μg/ml) and NCI-H187 (IC50 = 0.094 μg/ml) human cancer cell lines, antimalarial activity against Plasmodium falciparum (IC50 = 0.336 μg/ml), and antituberculosis activity against Mycobacterium tuberculosis (MIC = 6.25 μg/ml).

Bioactive polyprenylated benzophenone derivatives from the fruits extracts of Garcinia xanthochymus

Two new polycyclic prenylated xanthones (1 and 2) and a new phenylpropanoid glycoside (3), along with seven known compounds (4-10) were isolated from the fruits of Garcinia xanthochymus. The structures were elucidated by 1D- and 2D-NMR, and HRMS experiments. The isolates were evaluated for their inhibitory effects against the viability of U251MG glioblastoma and MDA-MB-231 breast cancer cells that harbor an aberrantly active signal transducer and exhibit activation of transcription 3 (STAT3), and compared to normal NIH3T3 mouse fibroblasts. Among the isolates, compounds 1, 2, 5, and 6-9 inhibited the viability of glioma cancer cells with IC50 values in the range of 1.6-6.5μM. Furthermore, treatment of U251MG with 6 and 7 inhibited intracellular STAT3 tyrosine phosphorylation and glioma cell migration in vitro, respectively.

Anti-inflammatory triterpenes from the apical bud of Gardenia sootepensis

Bioassay-guided fractionation of the dichloromethane extract from the apical bud of Gardenia sootepenesis Hutch. (Rubiaceae) led to the isolation of four new cycloartane triterpenes, sootepins F-I (1-4), along with four known derivatives (5-8). The structures of the new compounds were determined by 1D and 2D NMR experiments and by comparison of the physicochemical data with published values. The isolates were evaluated for cancer chemopreventive potential based on their ability to inhibit nitric oxide (NO) production and tumor necrosis factor-alpha (TNF-α)-induced nuclear factor kappa (NF-κB) activity. Compounds 6-8 inhibited TNF-α-induced NF-κB activity with half maximal inhibitory concentration (IC50) values of 8.3, 5.6, and 6.0μM, respectively; compounds 7 and 8 showed significant NO-inhibitory activity with IC50 values of 3.2 and 2.0μM, respectively.

5-Hy-droxy-8,8-dimethyl-10-(2-methyl-but-3-en-2-yl)-2H,6H-7,8-dihydro-pyrano[3,2-g]chromene-2,6-dione.

In the title compound, C19H20O5, the pyran ring is in an envelope conformation, whereas the benzene and dihydropyran ring system is planar with an r.m.s. deviation of 0.0190 (1) Å. The hydroxy group is coplanar with the attached benzene ring [r.m.s. deviation = 0.0106 (1) Å]. An intramolecular O—H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, molecules are linked into chains along the b axis by weak C—H⋯O interactions. These chains are stacked along the a axis. C—H⋯π and weak π–π interactions [centroid–centroid distance = 3.7698 (7) Å] are also observed.

Determination of the absolute configuration of chaetoviridins and other bioactive azaphilones from the endophytic fungus Chaetomium globosum.

Chemical investigation of an endophytic fungus Chaetomium globosum isolated from leaves of Wikstroemia uva-ursi led to the isolation of two new azaphilones, chaetoviridins J and K (1 and 3), along with five known derivatives (2 and 4-7). The structures of azaphilones were determined by NMR, X-ray diffraction, Moshers method, and CD analysis. The isolated compounds were evaluated for their cancer chemopreventive-potential based on their abilities to inhibit tumor necrosis factor alpha (TNF-α)-induced nuclear factor-kappa B (NF-κB). Compounds 4, 5, 7, and synthetic 8 and 9 inhibit nitric oxide (NO) production with IC50 values in the range of 0.3-5.8 μM. Compounds 4, 5, and 9 also displayed (TNF-α)-induced NF-κB activity with IC50 values in the range of 0.9-5.1 μM.