Hsiu Hui Chan

Camphoratins A−J, Potent Cytotoxic and Anti-inflammatory Triterpenoids from the Fruiting Body of Taiwanofungus camphoratus

Ten new triterpenoids, camphoratins A-J (1-10), along with 12 known compounds were isolated from the fruiting body of Taiwanofungus camphoratus. Their structures were established by spectroscopic analysis and chemical methods. Compound 10 is the first example of a naturally occurring ergosteroid with an unusual cis-C/D ring junction. Compounds 2-6 and 11 showed moderate to potent cytotoxicity, with EC(50) values ranging from 0.3 to 3 μM against KB and KB-VIN human cancer cell lines. Compounds 6, 10, 11, 14-16, 18, and 21 exhibited anti-inflammatory NO-production inhibition activity with IC(50) values of less than 5 μM, and were more potent than the nonspecific NOS inhibitor N(ω)-nitro-L-arginine methyl ester.

Isolation of substances with antiproliferative and apoptosis-inducing activities against leukemia cells from the leaves of Zanthoxylum ailanthoides Sieb. & Zucc

Extraction of the leaves of Zanthoxylum ailanthoides Sieb. & Zucc. affords extracts and four isolated compounds which exhibit activities against leukemia cells. The chloroform-soluble fraction (ZAC) of the crude extract of this plant showed cytotoxic activity against human promyelocytic leukemia (HL-60) and myelomonocytic leukemia (WEHI-3) cells with IC(50) values of 73.06 and 42.22 μg/mL, respectively. The active ZAC was further separated to yield pheophorbide-a methyl ester (1), pheophorbide-b methyl ester (2), 13(2)-hydroxyl (13(2)-S) pheophorbide-a methyl ester (3) and 13(2)-hydroxyl (13(2)-R) pheophorbide-b methyl ester (4) whose structures were confirmed by spectroscopic methods. Compounds 2-4 showed cytotoxic activities against both leukemia cells with IC(50) value in the range of 46.76-79.43 nM, whereas compound 1 exhibited only weak cytotoxic activity. The extracts and compounds 1-4 also induced apoptosis and DNA damage in leukemia cells after treatment. The results suggested that the Z. ailanthoides is biologically active against leukemia cells.

Bioactive constituents of Clausena lansium and a method for discrimination of aldose enantiomers

Glycosides, clausenosides A and B, and carbazole alkaloids, clausenaline A, claulamine A, and claulamine B, together with 50 known compounds, were isolated from the stems of Clausena lansium. Their structures were determined by means of spectroscopic methods, including that of CD and 1D/2D NMR analysis. Claulamine A has a 1-oxygenated carbazole skeleton with a rare 2,3-lactone ring, and claulamine B represents an hitherto unknown acetal carbazole alkaloid. Thirty-one of the isolated known compounds were evaluated in various assays for anti-inflammatory activity. Among them, imperatorin, isoheraclenin, and osthol exhibited selective and potent inhibition of formyl-l-methionyl-l-leucyl-l-phenylalanine/cytochalasin B (fMLP/CB)-induced superoxide anion generation, and lansiumarin C also decreased nitric oxide (NO) and tumor necrosis factor-α (TNF-α) production in lipopolysaccharide (LPS)-induced macrophages. In addition, a modified HPLC method of pre-column derivatization was developed that is more practical for simultaneous analysis of aldose enantiomers as compared to the literature method. The absolute configurations of the sugar moieties in clausenosides A and B were determined with this modified method.

Bioactive Constituents from the Roots of Panax japonicus var. MAJOR and Development of a LC-MS/MS Method for Distinguishing between Natural and Artifactual Compounds

Two new saponins, panajaponol (1) and pseudoginsenoside RT1 butyl ester (2), together with 35 known compounds (3-37), were isolated from the roots of Panax japonicus var. major. The structures of 1 and 2 were elucidated on the basis of spectroscopic analysis and chemical methods. Furthermore, a LC-MS/MS method was developed for confirming 2, 3, and 8 as natural compounds containing a butyl ester group. This method should be useful for distinguishing between minor natural and artifactual compounds in Panax species. Moreover, compounds 3, 6, 8, 9, 11, 13, and 15 exhibited strong inhibition of superoxide anion generation and elastase release by human neutrophils in response to formyl-l-methionyl-l-leucyl-l-phenylalanine/cytochalasin B (fMLP/CB), with IC(50) values ranging from 0.78 to 43.6 μM. In addition, 1 showed greater than 2- to 3-fold selective cytotoxic activity against KB and DU145 cancer cell lines.

Anti-inflammatory, anticholinesterase and antioxidative constituents from the roots and the leaves of Salvia nipponica Miq. var. formosana

Reactive oxygen species and granule proteases produced by neutrophils contribute to the pathogenesis of inflammatory diseases. The extracts of the roots and the leaves of Salvia nipponica var. formosana were showed potent inhibitory effects on superoxide anion production in fMLP/CB-activated human neutrophils as well as other anti-inflammatory effects, and led to the isolation of 25 compounds. Among them, compounds 8, 12, 13, 14, 15, 17 and 20 were exhibited more potent inhibitory effect on superoxide anion generation and elastase release by human neutrophils in response to fMLP/CB. Moreover, those isolated compounds also showed significant anticholinesterase and antioxidative activities. To the best of our knowledge, this is the first report of phytochemical and biological activity study on S. nipponica var. formosana.

UV-guided isolation of polyynes and polyenes from the roots of Codonopsis pilosula

The UV-guided isolation of polyacetylenes from the crude extract of Codonopsis pilosula has successfully led to the characterization of five new polyynes, pilosulynes A–E (1–5), and two new polyenes, pilosulynes F and G (6 and 7), as well as five known analogues (8–12). Their structures were determined by spectroscopic methods, including ICD and 1D/2D NMR experiments. The absolute configurations of the 6,7-diol moiety of the isolated compounds were determined by the Snatzkes method, which revealed an induced circular dichroism after the addition of dimolybdenum tetraacetate in DMSO. Compound 6 exhibited anti-HCV activity in the HCVcc infection assay with an EC50 value of 47.2 μM.

Ajugalide-B (ATMA) is an anoikis-inducing agent from Ajuga taiwanensis with antiproliferative activity against tumor cells in vitro

Ajuga taiwanensis is widely used for the treatment of hepatitis and hepatoma in Taiwanese folk medicine. However, its bioactive components and mechanism of action are unclear. Herein, ajugalide-B (ATMA), a neoclerodane diterpenoid isolated from Ajuga taiwanensis, is reported to exhibit high anti-proliferative activity against tumor cell lines from various tissues. These results demonstrate that ATMA disrupts the focal adhesion complex by decreasing phosphorylation of paxillin and focal adhesion kinase (FAK). As a result, anoikis, a specific type of apoptosis caused by detachment of cells, is triggered by activation of caspase-8 in A549 cells. Furthermore, ATMA also blocks anchorage-independent growth and cell migration and, therefore, ATMA may serve as a lead compound for the developing of anti-cancer therapeuties with anoikis-inducing properties.

Isolation and Synthesis of Melodamide A, a New Anti-inflammatory Phenolic Amide from the Leaves of Melodorum fruticosum

Together with twelve known compounds (2-13), melodamide A (1), a new phenolic amide possessing p-quinol moiety, was purified and characterized from the methanolic extracts of the leaves of Melodorum fruticosum. The structure of melodamide A (1) was established with a combination of 2D NMR experiments, HR-ESI-MS and X-ray analyses. The other known compounds were identified by comparison of their spectroscopic and physical data with those reported in the literature. Moreover, some isolated compounds were examined for their inhibitory activity towards superoxide anion generation and elastase release in human neutrophils. Among the tested compounds, 1, 3, and 5 exhibited strong inhibition of superoxide anion generation with IC50 values ranging from 5.25 to 8.65 µM. Furthermore, synthesis and biological evaluation of melodamide A (1) and its analogs (14a-p) were described.

A feasible and practical 1H NMR analytical method for the quality control and quantification of bioactive principles in Lycii Fructus

Lycii Fructus, a solanaceous drug, is widely used as functional foods and in Traditional Chinese Medicine. Samples collected from different regions of China have been found to be not identical in chemical compositions which might affect the biological activities. Although many chromatographic and spectrometric methods have been reported to determine the concentration of betaine and other bioactive amino acids, disturbance resulted from other polar substances with low UV-absorbance and expensive mass facilities reduced the applicability of these techniques. In the present study, the strong cation exchange solid phase extraction procedure incorporated with 1H NMR was successfully developed as a rapid and reliable method that can simultaneously determine betaine, citric acid, threonine, alanine, and proline in various Lycii Fructus. In addition, ERETIC 2 method based on PULCON principle was also applied and compared with conventional method. This feasible and practical method offers a very powerful tool for the quality control of commercial Lycii Fructus from different sources.

Mechanistic Study of Tetrahydrofuran-acetogenins In Triggering Endoplasmic Reticulum Stress Response-apotoposis in Human Nasopharyngeal Carcinoma

For past three decades, numerous studies have elucidated the antiproliferative effects of acetogenins in hopes of developing a new class of clinical anticancer agents. However, clear and definitive action mechanisms of acetogenins were less clarified. In the present study, three tetrahydrofuran (THF)-containing acetogenins were found to have potent and selective antiproliferative activity against human nasopharyngeal carcinoma (NPC) cell lines and their methotrexate-resistant counterparts. The THF-containing acetogenins induced G2/M phase arrest, mitochondrial damage and apoptosis, and increased cytosolic and mitochondrial Ca2+ in NPCs. Microarray analysis of NPC-TW01 cells treated with squamostatin A, a non-adjacent bis-THF acetogenin, demonstrated an increased endoplasmic reticulum (ER)-stress response (ESR). Enhanced ESR in squamostatin A-treated cells was confirmed by real-time PCR, Western blot and shRNA gene knockdown experiments. Although our results showed that squamostatin A-induced ESR was independent of extracellular Ca2+, the presence of extracellular Ca2+ enhanced the antiproliferative effect of acetogenins. In vivo analyses demonstrated that squamostatin A showed good pharmacokinetic properties and significantly retarded NPC tumor growth in the xenograft mouse model. Conclusively, our work demonstrates that acetogenins are effective and selective inducers of the ESR that can block NPC proliferation, and illustrate a previously unappreciated antitumor mechanism of acetogenins that is effective against nasopharyngeal malignancies.