Flavonoid composition of lemon-yellow sorghum genotypes

Flavonoid composition of lemon-yellow sorghums grown in two locations in Texas, USA was evaluated and compared with that of white and red sorghums using high performance liquid chromatography (HPLC-PDA). Sorghums from Lubbock were brighter in colour and had minimal weathering compared to those from College Station. Sorghums with red/purple secondary plant colour had the highest levels of 3-deoxyanthocyanidins (8–187 μg/g) and their levels were highest in grains from College Station (39–187 μg/g). Pericarp colour did not have any effect on 3-deoxyanthocyanidin levels (p > 0.05). The tan plant lemon-yellow sorghum Tx2953 had the highest levels of flavones (268–362 μg/g). Among the genotypes, lemon-yellow sorghums had the highest levels of flavanones (134–1780 μg/g), which are located in the pericarp and their levels were increased in the grains with a bright yellow pericarp and minimal weathering. The high flavanone levels in lemon-yellow sorghums makes this sorghum genotype a good source of those compounds.     

Quantitative analysis and recovery optimisation of flavonoids and anthocyanins in sugar-making process of sugarcane industry

Considering the possible comprehensive utilisation of bioactive constituents in the sugarcane industry, the flavonoids and anthocyanins in raw juice and various intermediate products within the sugar-making process were first analysed by HPLC-UV/DAD. The analysis was intended to reveal their distribution across the whole production chain. As their contents decreased during sugar production, a new strategy was developed and optimised to recover flavonoids and anthocyanins from raw juice, using A D141-type macroporous adsorptive resin for enrichment. The optimum process parameters were feeding with a pH value of 5.21, weight ratio of resin to crude sample of 20 (w/w), followed by adding 30% ethanol 3.57 times the column volume for anthocyanins with a flow rate of 1.69 bed volumes/h, then 100% ethanol 4.00 times the column volume for flavonoids with a flow rate of 2.36 bed volumes/h. Upon employing this method, an increase in efficiency was realised.     

Content of polyphenolic constituents and antioxidant activity of some Stachys taxa

Seven Croatian Stachys taxa (S. alpina, S. officinalis, S. palustris, S. recta subsp. recta, S. recta subsp. subcrenata, S. salviifolia and S. sylvatica) have been investigated in order to determine their content of biologically active compounds (polyphenols, tannins, phenolic acids and flavonoids) as well as their antioxidant activity. All taxa tested had a high content of total polyphenols, medium content of total phenolic acids, and a rather low content of tannins and flavonoids. The total phenolic acids content correlated significantly with total polyphenols content and the content of polyphenols unadsorbed on hide powder. A low correlation between plant phenolic acids and tannins was observed. Methanolic, ethanolic and dichloromethane extracts were investigated using DPPH, lipid peroxidase and xanthine oxidase assays. The extracts showed no inhibitory effects against lipid peroxidation and xanthine oxidase, but they had the ability to scavenge DPPH. The most effective in the DPPH assay were methanolic extracts of S. recta sub. recta and S. palustris whose radical scavenging activity was higher then that of the reference rutin. A low correlation between radical scavenging capacities of extracts with total flavonoids content was observed. The results indicate that investigated Stachys taxa exhibit potent antiradical activity and therefore could be a potential material for extracting free radical scavengers.     

Star-anise (Illicium verum) and black caraway (Carum nigrum) as natural antioxidants

The various solvent fractions of star-anise (Illicium verum) and black caraway (Carum nigrum), along with their spice powders and volatile oils, were prepared and evaluated for antioxygenic activity, using different methods. Star-anise powder and its ethanol/water (80:20)-soluble fraction showed strong antioxygenic activity in refined sunflower oil while the petroleum ether fraction exhibited marginal antioxygenic activity and the water-soluble fraction was practically devoid of any activity in sunflower oil. The black caraway powder showed marginal antioxygenic activity while its ethanol/water fraction (80:20) showed strong antioxygenic activity and all other fractions showed slight pro-oxygenic activity in refined sunflower oil. Both the spice powders and their extracts were also evaluated for antioxidant activity by linoleic acid peroxidaton, β-carotene-linoleate and 1, 1-diphenyl-2-picryl hydrazyl (DPPH) methods. Both the star-anise and black caraway powders, as well as their ethanol/water extracts, exhibited strong antioxygenic activity. Volatile oils from both the spices exhibited antioxygenic activity and the activity did not seem to be concentration-dependent. Volatile oils from star-anise showed relatively higher antioxygenic activity than did those from black caraway. Gas chromatography–mass spectroscopy (GC–MS) studies on star-anise and black caraway volatile oils resulted in the identification of 25 and 22 compounds, respectively, representing 94–97% of the total content.     

Molecular mechanisms for chemoprevention of colorectal cancer by natural dietary compounds

Colorectal cancer is one of the major causes of cancer-related mortality in both men and women worldwide. This review focuses on preventing the initiation and promotion of neoplastic growth in colorectal cancer, particularly with natural dietary compounds. Chemoprevention is defined as the use of natural dietary compounds and/or synthetic substances that can delay, prevent, or even reverse the development of adenomas, as well as the progression from adenoma to carcinoma. The molecular mechanisms of their chemopreventive action are associated with the modulation of signaling cascades, gene expressions involved in the regulation of cell proliferation, differentiation, and apoptosis and the suppression of chronic inflammation, metastasis, and angiogenesis. Here, we summarize the currently known targets and signaling pathways whereby natural dietary compounds interfere with the development of colorectal cancer, and thus providing evidence for these substances in colonic cancer chemopreventive action.     

HPLC分析芦苇叶中天然抗氧化成分黄酮类化合物

用高效液相色谱法（ＨＰＬＣ）成功地分离和制备了芦苇叶中天然抗氧化成分黄酮类化合物，并进行了定性和定量分析。     

不同热加工方式对黑米多酚含量和结构影响研究进展

黑米富含酚酸、黄酮、花青素等多种营养成分和生物活性物质,是一种有色稻米。黑米的热加工工艺有很多种,其中以蒸煮、挤压、干燥、微波等为主要热加工方式。挤压加工使黑米中酚酸含量损失10.27%~17.82%,高温高剪切力使酚酸发生降解脱羧、聚合;干燥加工使黑米中花青素含量下降了29.91%~65.10%,酚酸下降了1.97%~18.67%,酚类化合物发生热降解;蒸煮和微波处理分别使黑米中花青素含量损失65.4%~79.8%和69.3%~85.09%,花青素转化为原儿茶酸。本文综述了黑米中酚酸、黄酮和花青素的组成和功能,以及不同热加工处理对黑米中酚类物质含量和结构的影响研究进展,以期为黑米热加工的深入研究及其作为功能性米制食品的应用提供参考。     

Antiplatelet Effect and Selective Binding to Cyclooxygenase (COX) by Molecular Docking Analysis of Flavonoids and Lignans

The known flavonoids ginkgetin (1), taiwanhomoflavone A (2), taiwanhomoflavone B (3), and taiwanhomoflavone C (4) and eight known lignans: justicidin B (9), justicidin C (10), justicidin D (11), chinensinaphthol methyl ether (12), procumphthalide A (13), procumbenoside A (15), and ciliatosides A (16) and B (17) were isolated from Cephalotaxus wilsoniana and Justicia species, respectively. The antiplatelet effects of the above constituents on human platelet-rich plasma (PRP) were evaluated. Of the compounds tested on human PRP, compounds 1, 4, 9, and 11 showed inhibition of secondary aggregation induced by adrenaline. Compound 1 had an inhibitory effect on cyclooxygenase-1 (COX-1). Molecular docking studies revealed that 1 and the related compounds apigenin (5), cycloheterophyllin (6), broussoflavone F (7), and quercetin (8) were docked near the gate of active site of COX-1. It indicated that the antiplatelet effect of 1, 4, 9, and 11 is partially owed to suppression of COX-1 activity and reduced thromboxane formation. Flavonoids, 1, 5, 6, 7, and 8 may block the gate of the active site of COX-1 and interfere the conversion of arachidonic acid to prostaglandin (PG) H₂ in the COX-1 active site.     

Rutin content in buckwheat (Fagopyrum esculentum Moench) food materials and products

The rutin content of buckwheat products was compared to the rutin content in their raw materials, in order to evaluate their value for producing functional foods. There is much less rutin in noodles (78 mg/kg, d.w.b. – dry weight basis), than in the dark buckwheat flour (218 mg/kg, d.w.b.) from which they are produced. One of the possible explanations is the presence of the rutin degrading enzyme. In raw (uncooked) groats there is 230 mg/kg (d.w.b.) of rutin and in precooked groats, 88 mg/kg (d.w.b.). In buckwheat beer and vinegar there is a negligible content of rutin. Buckwheat leaf flour contains about 2700 mg/kg (d.w.b.) rutin, and is thus a suitable material for enriching functional foods, giving it the potential for preventive nutrition.     

钨酸钠-分光光度法测定银杏黄酮含量

提出了钨酸钠—分光光度法测定药物制剂中银杏黄酮含量的新方法。该法是基于银杏黄酮能与钨酸钠反应生成黄色钨酸酯，该物质在304nm处有最大吸收。该方法的线性范围为4—120μg/ml,r^2＝0．9997，回收率为100．0％—100．6％。