Suda Chakthong

Alkaloid and coumarins from the green fruits of Aegle marmelos

Five (1-5) and 15 known compounds were isolated from the acetone extract of the green fruits of Aegle marmelos. The structure of compounds 1-5, marmesiline (1), 6-(4-acetoxy-3-methyl-2-butenyl)-7-hydroxycoumarin (2), 6-(2-hydroxy-3-hydroxymethyl-3-butenyl)-7-hydroxycoumarin (3), marmelonine (4) and 8-hydroxysmyrindiol (5), were determined on the basis of spectroscopic analyses. Antifungal and antibacterial activities of selected compounds were also evaluated.

Naphthoquinones, Anthraquinones and Naphthalene Derivatives from the Bulbs of Eleutherine americana

A new naphthoquinone, named eleuthinone A ( 8), two new anthraquinones, named eleuthraquinone A and B ( 12, 13), a naphthalene derivative, named eleucanarol ( 14) were isolated from the bulbs of ELEUTHERINE AMERICANA, together with two new natural products previously synthesized, and nine known compounds. Their structures were established based on spectroscopic evidence. Their antibacterial activities against STAPHYLOCOCCUS AUREUS ATCC25923 and ATCC27664, an enterotoxin producing strain were investigated.

Carbazole-pyranocoumarin conjugate and two carbazole alkaloids from the stems of Clausena excavata

Abstract A carbazole-pyranocoumarin conjugate, carbazomarin B (1), and two carbazole alkaloids, 6-methoxymukonidine (2) and 2-hydroxy-3-methoxycarbazole (3), together with 27 known compounds (4–30), were isolated from the stems of Clausena excavata. Their structures have been elucidated by spectroscopic analyses. Compound 2 showed moderate cytotoxicity to HuCCA-1, MOLT-3 and HepG2 cancer cell lines with IC50 values of 15.09–28.50 μg/mL, but none to A549 cell line. Heptaphylline (6) and nordentatin (23) were found to show moderate cytotoxic activity against HepG2 cell line with IC50 values of 12.33 and 11.33, respectively, while clausine K (27) exhibited strong cytotoxicity with IC50 value of 1.05 μg/mL, better than a standard drug (etoposide, IC50 13.40 μg/mL).

New alkylamide from the stems of Zanthoxylum nitidum

Abstract A new alkylamide, named (2E,6E,8E)-N-(2-methylpropyl)-10-oxo-2,6,8-decatrienamide (1), together with 22 known compounds (2–23), were isolated from the stems of Zanthoxylum nitidum. Their structures were elucidated by spectroscopic methods, including 1D and 2D NMR spectroscopy. The isolated compounds exhibited slightly antioxidant activities through DPPH and ABTS radical scavenging assays but showed no antibacterial activity against Streptococcus mutans ATCC2517, a dental caries causing bacteria.

Constituents of Fagraea fragrans with Antimycobacterial Activity in Combination with Erythromycin

Seven new compounds constituted by three secoiridoids (1-3), two isocoumarins (4 and 5), an iridoid (6), and an aromatic derivative (7) in addition to 24 known compounds were isolated from the stem bark of Fagraea fragrans. The structures of the new compounds were determined on the basis of spectroscopic data analysis. The isolated compounds showed no antibacterial activity against Staphylococcus aureus and Escherichia coli. However, 5-formylisochromen-1-one (4), (-)-mellein (8), and swermacrolactone C (9) exhibited potent antimycobacterial activities against Mycobacterium smegmatis when used in combination with the antibiotic drug erythromycin.

Cytotoxic xanthones from the roots of Mesua ferrea L.

Five undescribed xanthones, 4-methoxypyranojacareubin, 4-hydroxy-3-prenylpyranoxanthone, 1-hydroxy-5,7-dimethoxyxanthone, 5-hydroxy-1,6,7-trimethoxyxanthone and 2-hydroxy-1,5-dimethoxyxanthone, together with thirty-three known xanthones were isolated from the roots of Mesua ferrea L. The structures of all isolated xanthones were elucidated based on spectroscopic methods. 5-Hydroxy-1,6,7-trimethoxyxanthone and 2-hydroxy-1,5-dimethoxyxanthone were also confirmed by X-ray diffraction data. In addition, the isolated compounds were determined for antibacterial, antioxidant and cytotoxic activities. The known 1,5,6-trihydroxyxanthone showed cytotoxicity against A375, PC-3 and HaCaT cell lines with IC50 values of 5.73 μg/mL, 5.93 μg/mL and 8.94 μg/mL, respectively.