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Two novel benzoquinones, uvarmicranones A (1) and B (2), along with 15 known compounds (3 − 17) were isolated from the stems of Uvaria micrantha (Annonaceae). Their structures were elucidated by analyses of NMR and high-resolution mass data. A plausible biosynthetic pathway of uvarmicranone A (1) via Diels-Alder cycloaddition reaction was also proposed. Some isolated compounds were evaluated for their cytotoxic activities. Compounds 1, 14, and 15 showed moderate cytotoxic effects against T-cell acute lymphoblastic cells (MOLT-3), with IC50 values of 7.83 ± 0.83, 6.53 ± 1.01, and 4.20 ± 0.29 μM, respectively. Additionally, compound 15 exhibited moderate cytotoxicity against cervical carcinoma cells (HeLa) with an IC50 value of 7.00 ± 3.15 μM. [ABSTRACT FROM AUTHOR]

Living organisms in Thailand are very diverse due to the unique geographical location of Thailand. The diversity of Thai bioresources has proven to be a rich source of biologically active compounds. The present review covers bioactive substances from Thai endophytic, marine-derived, insect pathogenic fungi and medicinal plants. Many new compounds isolated from Thai bioresources have diverse skeletons belonging to various classes of natural products. These compounds exhibited an array of biological activities, and some are of pharmaceutical interest. Bioactive compounds from Thai bioresources have not only attracted organic chemists to develop strategies for total synthesis, but also attracted (chemical) biologists to investigate the mechanisms of action. The chemistry and biology of some selected compounds are also discussed in this review. [ABSTRACT FROM AUTHOR]

The novel compound 1'''-hydroxy-2''',3'''-epoxylupinifolin (1), together with three known prenylated flavanones were identified from the stem of Derris reticulata during our reinvestigation of the plant. The structures were determined by spectroscopic methods including detailed study of NMR spectral data (DEPT, 2D-COSY, HMQC and HMBC) as well as by chemical derivatizations. [ABSTRACT FROM AUTHOR]

Natural products will continue to be the most prolific source of bioactive compounds. Natural products exhibiting antitumor activity continue to be the subject of extensive research aimed at the development of drugs for the treatment of different human tumors. It is generally accepted that natural products offer a diversity and complexity of structure unmatched by even the most active imaginations of synthetic organic chemists. This paper reviews the research of selected Thai plants for the discovery of therapeutic agents. Attention will be focused on our recent research on Thai plants that possess cytotoxic properties. Synthetic modification and reaction of some of these compounds aimed at enhancing their potency will also be presented. [ABSTRACT FROM AUTHOR]

A new 4-alkylcoumarin, mammea B/AC cyclo D (1), together with a 4-phenylcoumarin, mammea A/AC cyclo D (2), were isolated from the hexane extract of the dried flower of Mammea siamensis. Their structures were determined on the basis of spectroscopic evidence. [ABSTRACT FROM AUTHOR]

Bulbophyllum orchid is used as a folk medicine in Asia. However, the concentrations of bioactive constituents in the plant may vary in different tissues. Thus, this study determined the most cytotoxic tissue extract in Bulbophyllum blepharistes Rchb.f. and identified its cytotoxic bioactive compounds. The ethanol extract from rhizomes of B. blepharistes exhibits more cytotoxicity than extracts from the leaf and pseudobulb. Ten compounds isolated from the rhizome are phenanthrenes (1, 2), bibenzyls (3, 4, 5), phenylpropanoids (6), methyl benzoate (7), along with a mixture of three alkyl acrylates (8, 9, 10). Compound 2, lusianthridin (9,10-dihydro-7-methoxy-2,5-phenanthrenediol), which was reported here for the first time in Bulbophyllum , showed cytotoxicity to H69AR, HeLa, HL-60, HepG2, and MOLT-3 cells. Compound 1 and 5 (tristin) significantly inhibited the growth of MOLT-3. The rhizome of B. blepharistes appears to be a good source for the potential anticancer agents (i.e. lusianthridin). [Display omitted] • Among18 genera of Orchidaceae, the extract of Bulbophyllum showed the most cytotoxic effect. • The ethanolic extract from rhizome of Bulbophyllum orchid rich in bioactive compounds. • The cytotoxic of Bulbophyllum dihydrophenanthrene and bibenzyl effect to various cell lines. [ABSTRACT FROM AUTHOR]

Four sesterterpenes, erectusolides B, C, D, and seco-manoalide-25-methyl ether, two 2-furanone derivatives, erectusfuranones A and B, together with thirteen known sesterterpenes, (6Z)-neomanoalide-24-acetate, two diastereomers of 24-O-methylmanoalide, luffariolide B, manoalide, (6E)- and (6Z)-neomanoalide, seco-manoalide, scalarafuran, 12-acetylscalarolide, 12-epi-O-deacetyl-19-deoxyscalarin, 12-epi-scalarin, and 12-O-deacetyl-12-epi-scalarin, three indole alkaloids, 5-hydroxy-1H-indole-3-carbaldehyde, hyrtiosine A, and variabine B, and one norterpene, cavernosine were isolated from the marine sponge Hyrtios erectus. Their structures were determined by means of spectroscopic methods and the absolute configurations of the asymmetric centers were determined using the modified Mosher's method. The cytotoxic activities for the isolated compounds have been reported. [ABSTRACT FROM AUTHOR]

Metastasis, the spread of cancer in body, is a major cause of death. We have screened anti-metastatic activity of aqueous and dichloromethane extracts of several not previously studied Thai herbs, using an in vitro invasion test. This involves the in vitro invasion of HCC-S102, a hepatocellular carcinoma cell line derived from a Thai patient, through a reconstituted-basement membrane (Matrigel). The aqueous extract of a plant (Helixanthera parasitica) revealed a significant inhibitory effect on the cancer cell invasion, and showed antioxidant activity. The aqueous extract was partially purified by silica gel column chromatography, and the highest anti-metastatic activity fraction showed 83% inhibition of invasion with low cytotoxic effect. However, anti-metastatic activity was not associated with the antioxidant activity of the aqueous extract. [Copyright &y& Elsevier]

A new steroidal glycoside, callaphylloside (1), together with seven known glycosides (2-8), was isolated from the whole plant of Calamus acanthophyllus. The structure of the new compound was elucidated by spectral data analyses and chemical transformations. Compounds 5 and 8 exhibited strong cytotoxic activity against four cancer cell lines (0.7 ≤ IC50 ≤ 3.4 µM). Evaluation of the structure-activity relationship among steroidal glycosides revealed that the structure of spirostanol with an α-L-rhamnopyranosyl linked to C-2 of the inner glucopyranosyl residue both play a critical role in the effects of these compounds on the cancer cell lines., (Georg Thieme Verlag KG Stuttgart · New York.)

Chemical investigation of the Thai sponge Hyrtios gumminae collected from Similan Island in the Andaman Sea, Thailand, yielded four new sesterterpenoids, similan A (1), 12beta,20-dihydroxy-16beta-acetoxy-17-scalaren-19,20-olide (2), 12beta-acetoxy-20-hydroxy-17-scalaren-19,20-olide (3), and 12beta,16alpha,20-trihydroxy-17-scalaren-19,20-olide (4), together with seven known compounds. The structures of these new compounds were elucidated on the basis of their spectroscopic data and chemical transformations. Some of the isolated compounds were tested for their cytotoxic activity.

Two new clerodane diterpenes, methyl 15,16-epoxy-3,13(16),14- ENT-clerodatrien-18,19-olide-17-carboxylate ( 1) and dimethyl 15,16-epoxy-12-oxo-3,13(16),14- ENT-clerodatriene-17,18-dicarboxylate ( 2), together with seven known compounds ( 3 - 9), were isolated from the roots of Croton oblongifolius. The isolated compounds showed only mild cytotoxic activity against HuCCA-1, KB, HeLa, MDA-MB231, and T47D cell lines with IC (50) values ranging from 10 to 50 microg/mL.

Four new mammea coumarins, mammea E/BA cyclo D (1), mammea E/BC cyclo D (2), mammea E/BD cyclo D (3), and mammea E/AC cyclo D (4), were isolated from the flowers of Mammea siamensis, along with six known coumarins. Extensive 1D and 2D NMR experiments and other spectroscopic studies, as well as chemical transformations, were employed to determine the structures of 1-4.