Jyh-Horng Wu

Online RP-HPLC-DPPH screening method for detection of radical-scavenging phytochemicals from flowers of Acacia confusa.

Acacia confusa is traditionally used as a medicinal plant in Taiwan. In this study, phytochemicals and antioxidant activities of extracts from flowers of A. confusa were investigated for the first time. In addition, a rapid screening method, online RP-HPLC-DPPH system, for individual antioxidants in complex matrices was developed. Accordingly, six antioxidants including gallic acid ( 1), myricetin 3-rhamnoside ( 2), quercetin 3-rhamnoside ( 3), kaempferol 3-rhamnoside ( 4), europetin 3-rhamnoside ( 5), and rhamnetin 3-rhamnoside ( 6) were detected using the developed screening method. Of these, compounds 2, 3, and 5 were found to be major bioactive phytochemicals, and their contents were determined as 11.3, 6.7, and 8.7 mg/g of crude extract, respectively. By comparison with quercetin, a well-known antioxidant, these compounds had the order of compound 2 > compound 5 > quercetin > compound 3 for DPPH radical-scavenging activity. Their IC 50 values were 3.0, 3.2, 4.5, and 7.4 microM, respectively. Moreover, the same order was observed for superoxide radical-scavenging activity, and their IC50 values were 2.6, 2.7, 4.3, and 5.3 microM, respectively. However, for lipid peroxidation, quercetin, an aglycon, showed the best inhibitory activity. The IC50 values of quercetin, compound 2, compound 5, and compound 3 were 46.7, 88.5, 90.7, and 124.6 microM, respectively. These results indicated that a rhamnoside at the C3 position of flavonoids had a negative effect on radical-scavenging activity and antilipid peroxidation. In contrast, the number of hydroxyl groups on the B-ring exhibited a positive relationship with their inhibitory activities.

Protective effect of Acacia confusa bark extract and its active compound gallic acid against carbon tetrachloride-induced chronic liver injury in rats

Acacia confusa Merr. (Leguminosae), a species native to Taiwan, is widely distributed on the hills and lowlands of Taiwan, and has been traditionally used as a medicine. The hepatoprotective effects of A. confusa bark extract (ACBE) and its active constituent gallic acid were evaluated against carbon tetrachloride (CCl(4))-induced hepatotoxicity in rats. CCl(4)-induced hepatic pathological damage and significantly increased the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and malondialdehyde (MDA) in plasma, and cytochrome P4502E1 (CYP2E1) protein expression in hepatic samples, and decreased the activities of superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) in erythrocytes. Treatment with ACBE, gallic acid or silymarin could decrease significantly the AST, ALT, and MDA levels in plasma, and CYP2E1 expression in liver tissues, and increase the activities of SOD and GPX in erythrocyte when compared with CCl(4)-treated group. Liver histopathology also showed that ACBE, gallic acid or silymarin could significantly reduce the incidence of liver lesions induced by CCl(4). These results suggested that the ACBE and gallic acid exhibit potent hepatoprotection against CCl(4)-induced liver damages in rats, and the hepatoprotective effects of ACBE and gallic acid may be due to the modulation of antioxidant enzymes activities and inhibition of lipid peroxidation and CYP2E1 activation.

Antioxidant activities and phytochemical characteristics of extracts from Acacia confusa bark

The present study was carried out to evaluate the antioxidant activities of bark extract of Acacia confusa and some of the isolated constituents from its ethyl acetate (EtOAc) fraction in various in vitro systems to gain mechanistic insights. Results from antioxidant assays together with authentic antioxidant standards revealed that EtOAc fraction showed strong superoxide radical scavenging activity, reducing power, and ferrous ion-chelating ability. Following an in vitro antioxidant activity-guided fractionation procedure, 16 constituents including 12 benzoic acids, three cinnamic acids and one lignans were isolated and identified from the EtOAc fraction. We also evaluated the structure-activity relationships of benzoic and cinnamic acid derivatives. Results obtained indicated that the bark extracts and the derived phytochemicals from A. confusa have a great potential to prevent disease caused by the overproduction of radicals and also it might be used as a potential source of natural antioxidant agent.

Antioxidant Activity of Abietane-Type Diterpenes from Heartwood of Taiwania cryptomerioides Hayata

Summary Nine abietane-type diterpenes were isolated from the heartwood of Taiwania cryptomerioides and their structures identified by spectral analyses. Among these nine compounds, six diterpenes were isolated for the first time from T. cryptomerioides, including 6,7-dehydroferruginol, 6α-hydroxysugiol, 5,6-dehydro-6-hydroxysugiol, 11-hydroxyferruginol, secoabietane dialdehyde and isohinokiol. We suggest that abietane-type diterpenes are the dominant diterpenes in the heartwood of T. cryptomerioides. A possible biosynthesis pathway is proposed. In addition, a 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay was performed to evaluate the antioxidant activity of these diterpenes. This study demonstrates that ferruginol exhibits the strongest antioxidant activity among the diterpenes isolated from T. cryptomerioides heartwood.

A galactolipid possesses novel cancer chemopreventive effects by suppressing inflammatory mediators and mouse B16 melanoma.

Crassocephalum rabens (Asteraceae) is a popular anti-inflammatory folk medicine and food supplement. We investigated the cancer chemopreventive bioactivity of C. rabens phytocompounds in vitro and in vivo using cell- and gene-based bioassays and a mouse B16 melanoma model. The bioactive glyceroglycolipid 1,2-di-O-alpha-linolenoyl-3-O-beta-galactopyranosyl-sn-glycerol (dLGG) that was identified from C. rabens was found in vitro and in vivo to be a potent nitric oxide (NO) scavenger. dLGG treatment inhibited both mRNA and protein expression of inducible NO synthase and cyclooxygenase-2 (COX-2) in murine macrophages and inhibited COX-2 gene transcription in 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated B16 cells. In immunohistochemical studies, dLGG inhibited TPA-induced expression of COX-2 and nitration of proteins in mouse skin. dLGG could also significantly inhibit lipopolysaccharide-induced prostaglandin E(2) production in murine macrophages. Furthermore, dLGG prevented nuclear translocation of cytoplasmic nuclear factor-kappaB (NF-kappaB) by suppressing IkappaBalpha phosphorylation and degradation. Structure-activity relationship study by electrophoretic mobility shift assay indicated that the dilinolenoylglycerol moiety in dLGG is the essential structural feature preventing NF-kappaB.DNA complex formation. A dLGG-enriched extract from C. rabens (10 mg/kg) markedly suppressed B16 melanoma growth in C57BL/6J mice following i.p. administration, an effect comparable with that of cisplatin, a cancer chemotherapeutic drug. This study shows the detailed molecular mechanism(s) underlying the anti-inflammatory and tumor-suppressive effects of a natural galactolipid.

Green-color conservation of ma bamboo (Dendrocalamus latiflorus) treated with chromium-based reagents

The objectives of this study were to search for appropriate chemical reagents without arsenic to use as green-color protectors for ma bamboo (Dendrocalamus latiflorus Munro) culms and to compare the effectiveness of these reagents for green-color conservation. Bamboo culms treated with chromated copper phosphate (CCP) or chromated phosphate (CP), which were developed by us, exhibit a greener color than those treated with Boliden K-33 (type B chromated copper arsenate).The experimental results revealed that among the chemicals employed, CrO3 and H3PO4 were key components in conserving the green color of bamboo epidermis, and their ratio definitely affected the effectiveness of green-color conservation. When the CrO3/H3PO4 ratio was 1∶1, the treated bamboo culms displayed the greenest color. Among all the bamboo culms treated with different formulations of inorganic salts, the one treated with CP (1% CrO3, 1% H3PO4) had the best green-color conservation, enhanced by increasing the duration of treatment.

Antioxidant activity of extracts from Calocedrus formosana leaf, bark, and heartwood

Calocedrus formosana Florin (Cupressaceae) is an endemic tree to Taiwan. To evaluate the antioxidant activity of the plant extracts from heartwood, bark, and leaf of C. formosana, assays for 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and superoxide anion scavenging activities, as well as prevention of DNA strand cleavage were performed in this study. Similar IC50 values against the DPPH radical were found for the heartwood and bark extracts at approximately 23 µg/ml. Moreover, the heartwood extract exhibited the highest inhibitory activity against superoxide radicals among the test samples; a 2.3-fold lower value of IC50 for superoxide radical inhibition was found in the heartwood extract relative to that of (+)-catechin. Much less effect on inhibition of DPPH and superoxide radicals was found from the leaf extract of C. formosana. More than 70% of superoxide radicals were inhibited in the presence of 10 µg/ml heartwood extract, whereas only 15% inhibition was obtained from the leaf extract. The heartwood extract, at a dose of approximately 0.5 mg/ml, apparently completely prevented the ΦX174 supercoiled DNA cleavage induced by ultraviolet photolysis of H2O2, as judged by agarose gel electrophoresis. This report also suggests that the antioxidant activities of the plant extracts of C. formosana are in good correlation with their phenolic contents.

Mechanical and interfacial properties of plastic composite panels made from esterified bamboo particles

In this study, different extents of acetylated and butyrylated bamboo particle/plastic composites (BPPC) were produced by the flat-platen pressing process. The effect of esterification on mechanical and interfacial properties of BPPC was evaluated by a universal testing machine, X-ray diffractometer (XRD), 13C CP/MAS nuclear magnetic resonance (NMR) spectrometer, and scanning electron microscope (SEM). The results showed that the internal bond (IB) and wood screw-holding strength of BPPC were significantly increased after acetylation, even though the weight gain of acetylated bamboo particles was only 2%. In addition, SEM micrographs revealed that acetylated bamboo particles were effectively trapped by the polymeric matrix on the IB-fractured surface of BPPC. These results indicate that the interfacial interaction between the bamboo particle and the polymeric matrix can be enhanced through acetylation.

Anti-inflammatory lanostanoids and lactone derivatives from Antrodia camphorata.

Four new lanostanoids, ethyl lucidenate A (1), ethyl lucidenate F (2), 15-O-acetylganolucidate A (3), and 3,11,15,23-tetraoxo-27ξ-lanosta-8,16-dien-26-oic acid (4), and two new lactone derivatives, 5-hydroxy-5-(methoxymethyl)-4-methylfuran-2(5H)-one (5) and 3-(4-methoxy-2-oxo-2H-pyran-6-yl)propanoic acid (6), together with four known compounds, 11α-hydroxy-3,7-dioxolanost-8,24(E)-dien-26- oic acid (7), 3,7,11-trioxo-5α-lanosta-8,24(E)-dien-26-oic acid (8), methyl 3,7,11,12,15,23-hexaoxo-5α-lanost-8-en-26-oate (9), and ethyl 3,7,11,12,15,23-hexaoxo-5α-lanost-8-en-26-oate (10), were characterized from Antrodia camphorata. The structures of these new compounds were determined by analysis of their spectroscopic data, including 1D and 2D NMR experiments. Ten components were evaluated for anti-inflammatory activity by examining their effect on LPS-iNOS-dependent NO production in murine macrophage (RAW 264.7) cells. Among them, compounds 1, 3, 7, 8, 9, and 10 significantly suppressed the NO concentration in LPS-treated RAW 264.7 cells with IC50 values ≤ 10 μM.

Bioactive phytochemicals of leaf essential oils of Cinnamomum osmophloeum prevent lipopolysaccharide/ d -galactosamine (LPS/ d -GalN)-induced acute hepatitis in mice

The purpose of this study was to investigate the bioactive phytochemicals of leaf essential oils of Cinnamomum osmophloeum on lipopolysaccharide/D-galactosamine (LPS/D-GalN)-induced acute hepatitis. The results revealed that post-treatment with 100 μmol/kg trans-cinnamaldehyde, (-)-aromadendrene, T-cadinol, or α-cadinol significantly decreased the aspartate aminotransferase (AST), alanine aminotransferase (ALT), tumor necrosis factor-α (TNF-α), and interleukin 6 (IL-6) levels in serum. Moreover, both T-cadinol and α-cadinol treatments decreased the expressions of cleaved caspase-3 and cleaved poly-ADP ribose polymerase (PARP) in the liver tissues when compared with the LPS/D-GalN group. Liver histopathology also showed that silymarin, trans-cinnamaldehyde, (-)-aromadendrene, T-cadinol, or α-cadinol significantly reduced the incidence of liver lesions induced by LPS/D-GalN. These results suggest that the above phytochemicals exhibit potent hepatoprotection against LPS/D-GalN-induced liver damage in mice, and their hepatoprotective effects may be due to the modulation of anti-inflammatory activities.