Yen-Hsueh Tseng

Flavokawain B, a novel chalcone from Alpinia pricei Hayata with potent apoptotic activity: Involvement of ROS and GADD153 upstream of mitochondria-dependent apoptosis in HCT116 cells

Flavonoids synthesized from chalcone precursors in plants have been shown to possess cytotoxic activities with therapeutic potential. We have isolated the novel chalcone flavokawain B from Alpinia pricei Hayata, a plant native to Taiwan that is used in food and traditional Chinese medicine. Here, we report for the first time that flavokawain B significantly inhibits the growth of colon cancer cells and provide novel insight into the molecular mechanisms that underlie its apoptotic activity. Flavokawain B exerts its apoptotic action through ROS generation and GADD153 up-regulation, which lead to mitochondria-dependent apoptosis characterized by release of cytochrome c and translocation of Bak. The up-regulation of GADD153 in flavokawain B-treated HCT116 cells is associated with mitochondrial dysfunction and altered expression of Bcl-2 family members. Moreover, pretreatment with the ROS scavenger N-acetylcysteine abolishes flavokawain B-induced ROS generation, GADD153 up-regulation, and apoptosis. Similarly, RNAi-mediated gene silencing reduced flavokawain B-enhanced expression of GADD153 and apoptotic Bim, leading to diminished apoptosis. Interestingly, flavokawain B provokes G2/M accumulation as well as autophagy, in addition to apoptosis, suggesting that multiple pathways are activated in flavokawain B-mediated anticancer activity. Taken together, our data provide evidence for a molecular mechanism to explain the apoptotic activity of Alpinia plants, showing that flavokawain B acts through ROS generation and GADD153 up-regulation to regulate the expression of Bcl-2 family members, thereby inducing mitochondrial dysfunction and apoptosis in HCT116 cells.

Anti-inflammatory Activity of Flavokawain B from Alpinia pricei Hayata

Alpinia pricei (Zingiberaceae) is a spicy herb indigenous to Taiwan. A potent anti-inflammatory compound, flavokawain B (FKB), was obtained from A. pricei. FKB significantly inhibited production of NO and PGE(2) in LPS-induced RAW 264.7 cells. Moreover, it also notably decreased the secretion of TNF-alpha. Expression of iNOS and COX-2 proteins was also inhibited by FKB in a dose-dependent manner. FKB blocked the nuclear translocation of NF-kappaB induced by LPS, which was associated with prevention IkappaB degradation, and subsequently decreased NF-kappaB protein levels in the nucleus. Similar anti-inflammatory activities of FKB were observed in an animal assay. NO concentrations in mouse serum rose dramatically from 3.2 to 28.8 microM after mice were challenged with LPS; however, preadministration of 200 mg/kg FKB reduced the NO concentration to 3.8 microM after challenge with LPS. Moreover, FKB strongly suppressed LPS-induced iNOS, COX-2, and NF-kappaB proteins expression in mouse liver.

Bioactivity Investigation of Lauraceae Trees Grown in Taiwan

Abstract This research collected 27 Lauraceae tree species in Taiwan, and the extracts prepared from leaves and branches were selected to evaluate and characterize their putative bioactivities and potential medicinal applications. Several bioactivity assays, including antifungal tests, antioxidant evaluation, anti-inflammation activity, and cytotoxicity were preformed in this study.The results showed no significant antifungal activity by Lauraceae extracts. Neolitsea parvigemma. (Hay.) Kanehira et Sasaki expresses the best antioxidant activity (IC50 = 5.73 µg/mL) in the DPPH assay.The extracts of Litsea akoensis. Hay. and Cryptocarya concinna. Hance had significant anti-inflammation activity, and they can inhibit the nitric oxide (NO) production in the LPS-induced microphage assay at the dose of 25 µg/mL. According to the cytotoxicity assay, Lindera aggregate. (Sims) Kosterm and Cryptocarya concinna. Hance extracts showed in vitro. cytotoxicity against human umbilical vein endothelial cell line (HUVEC) with IC50 values of 43.15 µg/mL and 49.36 µg/mL, respectively, and Phoebe formosana. (Matsum. et Hay.) Hay. extract exhibited marked cytotoxicity (IC50 = 42.87 µg/mL) against a human leukemia cell line (HL-60). Results from this preliminary investigation suggest that these Lauraceae tree species may have a great potential for further development as cancer chemoprevention agents or food supplements for promoting human health.

The effect of the aerial part of Lindera akoensis on lipopolysaccharides (LPS)-induced nitric oxide production in RAW264.7 cells.

Four new secondary metabolites, 3α-((E)-Dodec-1-enyl)-4β-hydroxy-5β-methyldihydrofuran-2-one (1), linderinol (6), 4′-O-methylkaempferol 3-O-α-l-(4″-E-p-coumaroyl)rhamnoside (11) and kaempferol 3-O-α-l-(4″-Z-p-coumaroyl) rhamnoside (12) with eleven known compounds—3-epilistenolide D1 (2), 3-epilistenolide D2 (3), (3Z,4α,5β)-3-(dodec-11-ynylidene)-4-hydroxy-5-methylbutanolide (4), (3E,4β,5β)-3-(dodec-11-ynylidene)-4-hydroxy-5-methylbutanolide (5), matairesinol (7), syringaresinol (8), (+)-pinoresinol (9), salicifoliol (10), 4″-p-coumaroylafzelin (13), catechin (14) and epicatechin (15)—were first isolated from the aerial part of Lindera akoensis. Their structures were determined by detailed analysis of 1D- and 2D-NMR spectroscopic data. All of the compounds isolated from Lindera akoensis showed that in vitro anti-inflammatory activity decreases the LPS-stimulated production of nitric oxide (NO) in RAW 264.7 cell, with IC50 values of 4.1–413.8 μM.

Inhibitory effect of human breast cancer cell proliferation via p21-mediated G1 cell cycle arrest by araliadiol isolated from Aralia cordata Thunb.

A new polyacetylenic compound, araliadiol, was isolated from the leaves of Aralia cordata Thunb. (Araliaceae). The structure of araliadiol was determined to be 3( S),8( R)-pentadeca-1,9( Z)-diene-4,6-diyne-3,8-diol by MS, NMR, IR, and UV spectroscopic analysis as well as Mosher ester reaction. Araliadiol displayed a significant inhibitory effect on the growth of a human breast adenocarcinoma cell line (MCF-7), with an IC (50) value for cytotoxicity of 6.41 µg/mL. Cell cycle analysis revealed that the proportion of cells in the G (1) phase of the cell cycle increased in a dose-dependent manner (from 54.7 % to 72.0 %) after 48 h exposure to araliadiol at dosages ranging from 0 to 80 µM. The results suggest that araliadiol inhibits cell cycle progression of MCF-7 at the G (1)-S transition. After treatment with araliadiol, phosphorylation of retinoblastoma protein (Rb) in MCF-7 cells was inhibited, accompanied by a decrease in the levels of cyclin D (3) and cyclin-dependent kinase 4 (cdk4) and an increase in the expression of p21 (WAF-1/Cip1). However, the expression of phosphorylated p53 (Ser15) and Chk2 was not altered in MCF-7 cells. These findings indicate that araliadiol exhibits its growth-inhibitory effects on MCF-7 cells through downregulation of cdk4 and cyclin D (3), and upregulation of p21 (WAF-1/Cip1) by a p53-independent mechanism.

A New Butanolide Compound from the Aerial Part of Lindera akoensis with Anti-inflammatory Activity

A new butanolide, 3β-((E)-dodec-1-enyl)-4β-hydroxy-5β-methyldihydrofuran-2-one (1) and four known butanolides: Akolactone A (2), (3Z,4α,5β)-3-(dodec-11-enylidene)-4-hydroxy-5-methylbutalactone (3), (3E,4α,5β)-3-(dodec-11-enylidene)-4-hydroxy-5-methylbutalactone (4) and dihydroisoobtusilactone (5), were isolated from the aerial parts of Lindera akoensis. These butanolides showed in vitro anti-inflammatory activity decrease the LPS-stimulated production of nitrite in RAW264.7 cell, with IC50 values of 1.4–179.9 μM.

Composition and antifungal activity of balsam from Liquidambar formosana Hance

Abstract Formosan sweet gum (Liquidambar formosana Hance) is a tree species endemic in Taiwan. In this study, the composition of balsam from L. formosana has been determined by several chromatographic and spectroscopic techniques. Among the 26 compounds identified, three new triterpenoids were detected, namely, 2α,3α-dihydroxyolean-12-en-28-al (1), 3α-hydroxyolean-12-en-30-ol (2), and 3α-hydroxyolean-2-oxo-12-en-28-al (3). The most abundant volatile compounds were β-caryophyllene (22.7%), α-pinene (23.3%), and β-pinene (19.6%), and the most abundant nonvolatile compounds were 3α,25-dihydroxyolean-12-en-28-oic acid (12, 19.1%), oleanonic aldehyde (9, 14.0%), and betulonic acid (15, 13.4%). The compounds 3α,25-dihydroxyolean-12-en-28-oic acid and bornyl cinnamate were found to be inhibitory for white rot (Lenzites betulina) and brown rot (Laetiporus sulphureus) fungi.

Lonicera hypoglauca inhibits xanthine oxidase and reduces serum uric acid in mice.

Xanthine oxidase (XOD) catalyzes the oxidation of hypoxanthine to xanthine and then to uric acid, and is a key enzyme in the pathogenesis of hyperuricemia. The ability of extracts of Lonicera hypoglauca (Caprifoliaceae) to inhibit XOD was investigated in this study. An ethanol extract (LH-crude) of the leaves of L. hypoglauca and its derived EtOAc soluble sub-fractions (LH-EA) significantly inhibited XOD activity, with IC50 values for LH-crude and LH-EA of 48.8 and 35.2 microg/mL. Moreover, LH-EA reduced serum urate levels IN VIVO in a potassium oxonate-induced hyperuricemic mouse model, by 70.1% and 93.7% of the hyperuricemic untreated group at doses of 300 and 500 mg/kg of LH-EA, respectively. Finally, we used bioactivity-guided fractionation to isolate a new bisflavonoid, loniceraflavone, which showed significant inhibition of XOD (IC50=0.85 microg/mL). These results suggest that L. hypoglauca and its extracts may have a considerable potential for development as an anti-hyperuricemia agent for clinical application.

Cardenolides and bufadienolide glycosides from Kalanchoe tubiflora and evaluation of cytotoxicity.

Two new cardenolides, kalantubolide A (1) and kalantubolide B (2), and two bufadienolide glycosides, kalantuboside A (3) and kalantuboside B (4), as well as eleven known compounds were isolated and characterized from the EtOH extract of Kalanchoe tubiflora. The structures of compounds were assigned based on 1D and 2D NMR spectroscopic analyses including HMQC, HMBC, and NOESY. Biological evaluation indicated that cardenolides (1-2) and bufadienolide glycosides (3-7) showed strong cytotoxicity against four human tumor cell lines (A549, Cal-27, A2058, and HL-60) with IC50 values ranging from 0.01 µM to 10.66 µM. Cardenolides (1-2) also displayed significant cytotoxicity toward HL-60 tumor cell line. In addition, compounds 3, 4, 5, 6, and 7 blocked the cell cycle in the G2/M-phase and induced apoptosis in HL-60 cells.

Heteropolygonatum altelobatum (Asparagaceae), comb. nova

Heteropolygonatum has been considered endemic to China, where most of the species are distributed in the SW region of the country. The genus is characterized by having both terminal and axillary inflorescences, inner and outer stamens of different lengths, and an epiphytic existence. Formerly, a number of the species were included in Polygonatum or Smilacina. Polygonatum altelobatum Hayata is an endemic of Taiwan; however, a review of the literature and field observations confirmed that it should be placed in Heteropolygonatum. Thus, we propose the new combination Heteropolygonatum altelobatum (Hayata) Y.H. Tseng, H.Y. Tzeng & C.T. Chao.