Pi-Yu Chao

Antioxidant activity of herbaceous plant extracts protect against hydrogenperoxide-induced DNA damage in human lymphocytes

BackgroundHerbaceous plants containing antioxidants can protect against DNA damage. Thepurpose of this study was to evaluate the antioxidant substances,antioxidant activity, and protection of DNA from oxidative damage in humanlymphocytes induced by hydrogen peroxide (H2O2). Ourmethods used acidic methanol and water extractions from six herbaceousplants, including Bidens alba (BA), Lycium chinense (LC),Mentha arvensis (MA), Plantago asiatica (PA),Houttuynia cordata (HC), and Centella asiatica(CA).MethodsAntioxidant compounds such as flavonol and polyphenol were analyzed.Antioxidant activity was determined by the inhibition percentage ofconjugated diene formation in a linoleic acid emulsion system and bytrolox-equivalent antioxidant capacity (TEAC) assay. Their antioxidativecapacities for protecting human lymphocyte DNA fromH2O2-induced strand breaks was evaluated by cometassay.ResultsThe studied plants were found to be rich in flavonols, especially myricetinin BA, morin in MA, quercetin in HC, and kaemperol in CA. In addition,polyphenol abounded in BA and CA. The best conjugated diene formationinhibition percentage was found in the acidic methanolic extract of PA.Regarding TEAC, the best antioxidant activity was generated from the acidicmethanolic extract of HC. Water and acidic methanolic extracts of MA and HCboth had better inhibition percentages of tail DNA% and tail moment ascompared to the rest of the tested extracts, and significantly suppressedoxidative damage to lymphocyte DNA.ConclusionQuercetin and morin are important for preventing peroxidation and oxidativedamage to DNA, and the leaves of MA and HC extracts may have excellentpotential as functional ingredients representing potential sources ofnatural antioxidants.

Antioxidant Activity in Extracts of 27 Indigenous Taiwanese Vegetables

The objectives of this study were to identify the antioxidants and antioxidant axtivity in 27 of Taiwan’s indigenous vegetables. Lycium chinense (Lc), Lactuca indica (Li), and Perilla ocymoides (Po) contained abundant quercetin (Que), while Artemisia lactiflora (Al) and Gynura bicolor (Gb) were rich in morin and kaempferol, respectively. Additionally, Nymphoides cristata (Nc) and Sechium edule (Se)-yellow had significantly higher levels of myricetin (Myr) than other tested samples. Cyanidin (Cyan) and malvidin (Mal) were abundant in Gb, Abelmoschus esculentus Moench (Abe), Po, Anisogonium esculentum (Retz.) Presl (Ane), Ipomoea batatas (Ib)-purple, and Hemerocallis fulva (Hf)-bright orange. Relatively high levels of Trolox equivalent antioxidant capacity (TEAC), oxygen radical absorption capacity (ORAC), and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenger were generated from extracts of Toona sinensis (Ts) and Po. Significant and positive correlations between antioxidant activity and polyphenols, anthocyanidins, Que, Myr, and morin were observed, indicating that these phytochemicals were some of the main components responsible for the antioxidant activity of tested plants. The much higher antioxidant activity of Po, Ts, and Ib (purple leaf) may be related to their higher Cyan, Que, and polyphenol content.

Naturally occurring chlorophyll derivatives inhibit aflatoxin B1-DNA adduct formation in hepatoma cells

The inhibitory effects of four chlorophyll derivatives (chlorophyllide [Chlide] a and b and pheophorbide [Pho] a and b) on aflatoxin B1 (AFB1)-DNA adduct formation, and on the modulation of hepatic glutathione S-transferase (GST) were evaluated in murine hepatoma (Hepa-1) cells. Enzyme-linked immunosorbent assay showed that pretreatment with Chlide or Pho significantly reduced the formation of AFB1-DNA adducts, and that Pho was the most potent inhibitor. However, wash-out prior to adding AFB1 totally eliminated inhibition by Childe and partially eliminated inhibition by Pho, indicating that the inhibitory effect of Chlide, and to some extent Pho, was mediated through direct trapping of AFB1. Furthermore, spectrophotometric analysis showed that Pho treatment could increase GST activity in Hepa-1 cells. These observations indicate that the chlorophyll derivatives studied may attenuate AFB1-induced DNA damage in the Hepa-1 cell by direct trapping of AFB1. Pho provided additional protection not only by direct trapping, but also by increasing GST activity against hepatic AFB1 metabolites.

Inhibitive Effects of Mulberry Leaf-Related Extracts on Cell Adhesion and Inflammatory Response in Human Aortic Endothelial Cells

Effects of mulberry leaf-related extracts (MLREs) on hydrogen peroxide-induced DNA damage in human lymphocytes and on inflammatory signaling pathways in human aortic endothelial cells (HAECs) were studied. The tested MLREs were rich in flavonols, especially bombyx faces tea (BT) in quercetin and kaempferol. Polyphenols, flavonoids, and anthocyanidin also abounded in BT. The best trolox equivalent antioxidant capacity (TEAC) was generated from the acidic methanolic extracts of BT. Acidic methanolic and water extracts of mulberry leaf tea (MT), mulberry leaf (M), and BT significantly inhibited DNA oxidative damage to lymphocytes based on the comet assay as compared to the H2O2-treated group. TNF-α-induced monocyte-endothelial cell adhesion was significantly suppressed by MLREs. Additionally, nuclear factor kappa B (NF-κB) expression was significantly reduced by BT and MT. Significant reductions were also observed in both NF-κB and activator protein (AP)-1 DNA binding by MLREs. Significant increases in peroxisome proliferator-activated receptor (PPAR) α and γ DNA binding by MLREs were also detected in M and MT extracts, but no evidence for PPAR α DNA binding in 50 μg/mL MT extract was found. Apparently, MLREs can provide distinct cytoprotective mechanisms that may contribute to its putative beneficial effects on suppressing endothelial responses to cytokines during inflammation.

Chlorophyll-Related Compounds Inhibit Cell Adhesion and Inflammation in Human Aortic Cells

The objectives of this study were to investigate the effects of chlorophyll-related compounds (CRCs) and chlorophyll (Chl) a+b on inflammation in human aortic endothelial cells. Adhesion molecule expression and interleukin (IL)-8, nuclear factor (NF)-κB p65 protein, and NF-κB and activator protein (AP)-1 DNA binding were assessed. The effects of CRCs on inflammatory signaling pathways of signal transducers and activators of transcription 3 (STAT3) and mothers against decapentaplegic homolog 4, respectively induced by IL-6 and transforming growth factor (TGF)-β, in human aortic smooth muscle cells cultured in vitro were also investigated. HAECs were pretreated with 10 μM of CRCs, Chl a+b, and aspirin (Asp) for 18 h followed by tumor necrosis factor (TNF)-α (2 ng/mL) for 6 h, and U937 cell adhesion was determined. TNF-α-induced monocyte-endothelial cell adhesion was significantly inhibited by CRCs. Moreover, CRCs and Chl a+b significantly attenuated vascular cell adhesion molecule-1, intercellular adhesion molecule-1, and IL-8 expressions. Treatments also significantly decreased in NF-κB expression, DNA binding, and AP-1 DNA binding by CRCs and Asp. Thus, CRCs exert anti-inflammatory effects through modulation of NF-κB and AP-1 signaling. Ten micromoles of CRCs and Asp upregulated the expression of mothers against decapentaplegic homolog 4 (Drosophila) (SMAD4) in the TGF-β receptor signaling pathway, and SMAD3/4 transcription activity was also increased. Ten micromoles of CRCs were able to potently inhibit STAT3-binding activity by repressing IL-6-induced STAT3 expression. Our results provide a potential mechanism that explains the anti-inflammatory activities of these CRCs.

Grey relational analysis between agronomic characters and maturity of sugarcane

This study applied grey system theory to analyze the relationship between eight agronomic characters including plant height, leaf fresh weight, leaf dry weight, leaf water content, internodes number of dead-leaf stalk, internodes number of green-leaf stalk, juice brix of dead-leaf stalk and juice brix of green-leaf stalk, and the maturity of sugarcane. The contribution degrees of agronomic characters, indicated by grey order, to maturity of sugarcane were: juice brix of green-leaf stalk＞leaf dry weight＞juice brix of dead-leaf stalk＞plant height＞internodes number of green-leaf stalk＞leaf fresh weight＞leaf water content＞internodes number of dead-leaf stalk. Therefore, the juice brix of green-leaf stalk and dead-leaf stalk, leaf dry weight and plant height were the most critical characters to the maturity of sugarcane. The result based on grey relational analysis might be used as a valuable reference on the field management of sugarcane.