[show abstract][hide abstract] ABSTRACT: The dietary polyphenols as α-glucosidases inhibitors have attracted great interest among researchers. The aim of this review is to give an overview of the research reports on the structure-activity relationship of dietary polyphenols inhibiting α-glucosidases. The molecular structures that influence the inhibition are the following: (1) The hydroxylation and galloylation of flavonoids including catechins improve the inhibitory activity. (2) The glycosylation of hyroxyl group and hydrogenation of the C2=C3 double bond on flavonoids weaken the inhibition. (3) However, cyaniding glycosides show higher inhibition against than cyanidin. Proanthocyanidins oligomers exhibit a stronger inhibitory activity than their polymers. (4) The hydroxylation on B ring and the glycosylation of stilbenes reduce the inhibitory activity. (5) Caffeoylquinic acids display strong inhibition against α-glucosidases. However, hydroxycinnamic acid, ferulic acid, and gallic acid hardly inhibited α-glucosidases. (6) The coupled galloyl structures attached to C-3 and C-6 of the 4C(1) glucose core of ellagitanin gave basic inhibitory activity. (7) The mono-glycosylation of chalcones slightly lowers the inhibition. However, the diglycosylation of chalcones significantly decreased the activity.
Critical reviews in food science and nutrition 01/2013; 53(8):818-36. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: The inhibitory effects of dietary polyphenols against α-amylase have attracted great interest among researchers. The aim of this review is to give an overview of the research reports on the structure-activity relationship of polyphenols inhibiting α-amylase. The molecular structures that influence the inhibition are the following: (1) The hydroxylation of flavonoids improved the inhibitory effect on α-amylase; (2) Presence of an unsaturated 2,3-bond in conjugation with a 4-carbonyl group has been associated with stronger inhibition; (3) The glycosylation of flavonoids decreased the inhibitory effect on α-amylase depending on the conjugation site and the class of sugar moiety; (4) The methylation and methoxylation of flavonoids obviously weakened the inhibitory effect; (5) The galloylated catechins have higher inhibition than nongalloylated catechins; the catechol-type catechins were stronger than the pyrogallol-type catechins; the inhibition activities of the catechins with 2,3-trans structure were higher than those of the catechins with 2,3-cis structure; (6) Cyanidin-3-glucoside showed higher inhibition against than cyanidin and cyanidin-3-galactoside and cyanidin-3,5-diglucoside had no inhibitory activity; (7) Ellagitannins with β-galloyl groups at glucose C-1 positions have higher inhibitory effect than the α-galloyl and nongalloyl compounds and the molecular weight of ellagitannins is not an important element.
Critical reviews in food science and nutrition 01/2013; 53(5):497-506. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Tropane alkaloids (TA) including hyoscyamine, anisodamine, scopolamine and anisodine, are used medicinally as anticholinergic agents with increasing market demand, so it is very important to improve TA production by metabolic engineering strategy. Here, we report the simultaneous introduction of genes encoding the branch-controlling enzyme tropinone reductase I (TRI, EU424321) and the downstream rate-limiting enzyme hyoscyamine-6β-hydroxylase (H6H, EF187826) involved in TA biosynthesis into Anisodus acutangulus hairy roots by Agrobacterium-mediated gene transfer technology. Transgenic hairy root lines expressing both TRI and H6H (TH lines) produced significantly higher (P < 0.05) levels of TA compared with the control and single gene transformed lines (T or H lines). The best double gene transformed line (TH53) produced 4.293 mg g(-1) TA, which was about 4.49-fold higher than that of the control lines (0.96 mg g(-1)). As far as it is known, this is the first report on simultaneous introduction of TRI and H6H genes into TA-producing plant by biotechnological approaches. Besides, the content of anisodine was also greatly improved in A. acutangulus by over-expression of AaTRI and AaH6H genes. The average content of anisodine in TH lines was 0.984 mg g(-1) dw, about 18.57-fold of BC lines (0.053 mg g(-1) dw). This is the first time that this phenomenon has been found in TA-producing plants.
[show abstract][hide abstract] ABSTRACT: The aphid is one of the most serious pests that causes damage to crops worldwide. Lectins from Araceae plant had been proved useful to control the aphid. Herein, the full-length cDNA of Monstera deliciosa agglutinin (mda) gene was cloned and then introduced into tobacco and the influence of the expression of mda in transgenic tobacco against peach-potato aphids (Myzus persicae) was investigated. Among 92 regenerated plants, 59 positive tobacco lines were obtained. Real-time PCR assays and aphid bioassay test revealed that there is a positive correlation between the expression level of mda and the inhibitory effect on peach-potato aphids. The average anti-pests ability of mda transgenic tobacco was 74%, which was higher than that of other reported lectins from Araceae plant. These results indicated that MDA is one of promising insect resistance proteins selected for the control of peach-potato aphids.
[show abstract][hide abstract] ABSTRACT: Diabetes is characterized by an elevated level of glucose in the blood. This glucose can form covalent adducts with plasma proteins through a non-enzymatic process known as glycation. It has been suggested that the increasing glycation can influence the ability of plasma proteins to bind to small molecules. Herein, the difference between healthy human plasma proteins (HPP) and type II diabetes plasma proteins (TPP) in binding small molecules was investigated. TPP showed about 1-10 times lower affinities for polyphenols than HPP. The values of lg K(a)(HPP) are positive proportional to the values of lg K(a)(TPP) with excellent linear relationship. The glycation of HPP decreased the affinities for HPP by about 1.17 to 16.6 times. The difference between HPP-polyphenol interaction and TPP-polyphenol interaction was bigger for the more lipophilic polyphenols. The affinities for TPP or HPP slightly decreased with increasing hydrogen bond donor numbers of polyphenols and hardly changed with hydrogen bond acceptor numbers.
[show abstract][hide abstract] ABSTRACT: The interactions between polyphenols, especially flavonoids and plasma proteins, have attracted great interest among researchers. Few papers, however, have focused on the structure-affinity relationship of polyphenols on their affinities for plasma proteins. The aim of this review is to give an overview of the research reports on the characterization, influence on the bioactivity, and the structure-affinity relationship for studying the affinities between polyphenols and plasma proteins. The molecular properties that influence the affinities of polyphenols for plasma proteins are the following: 1) One or more hydroxyl groups in the B-ring (e.g., 3',4' dihydroxylated B ring catechol group) of flavonoids enhanced the binding affinities to proteins. However, the hydroxyl group in the C-ring will weaken the binding interaction. 2) The presence of an unsaturated 2,3-bond in conjugation with a 4-carbonyl group, characteristic of flavonols structure, has been associated with stronger binding affinity with plasma proteins; 3) The glycosylation of flavonoids decreases the affinities for plasma proteins by 1-3 orders of magnitude depending on the conjugation site and the class of sugar moiety; 4) The methylation of hydroxyl groups in flavonoids slightly enhanced the affinities for plasma proteins by 2-16 times; 5) The galloylated catechins have higher binding affinities for plasma proteins than do non-galloylated catechins and the pyrogallol-type catechins have higher affinities than do the catechol-type catechins. The affinity of the catechin with 2,3-trans structure was lower than those of the catechin with 2,3-cis structure; 6) The gallotannins with more gallol groups presented a much higher percentage of binding to plasma proteins. α-D-Gallotannin showed a greater affinity for plasma proteins than does the natural stereoisomer, β-D-gallotannin; 7) The binding degree of chlorogenic acid with only one caffeoyl group was lower than the binding degrees of caffeoyl quinic acids with more caffeoyl groups. The methylation of phenolic acid decreased the affinity for BSA.
Critical reviews in food science and nutrition 01/2012; 52(1):85-101. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: The molecular structure/property-affinity relationships of dietary polyphenols non-covalently binding to total plasma proteins of type II diabetes (IIDTPP) were investigated by comparing the binding constants obtained from the fluorescence titration method. An additional methoxy group in flavonoids increased their binding affinities for IIDTPP by 1.38 to 15.85 times. The hydroxylation at the 4' position (Ring B) of flavonols and the 5 position (Ring A) of isoflavones weakened the binding affinities; however, hydroxylation at other positions on flavonoids slightly enhanced or little affected the binding affinities for IIDTPP. The glycosylation of flavonoids slightly decreased or little affected the affinities for IIDTPP by less than 1 order of magnitude. The hydrogenation of the C2[double bond, length as m-dash]C3 double bond of flavone, 6-hydroxyflavone, 6-methoxyflavone and myricetin decreased the binding affinities. The galloylation of catechins significantly improved the binding affinities with IIDTPP approximately 10 to 1000 times. The esterification of gallic acid increased its binding affinity. The hydrophobic force played an important role in the binding interaction between polyphenols and IIDTPP.
[show abstract][hide abstract] ABSTRACT: The four tropane alkaloids have played a pivotal role in controlling diseases such as the toxic and septic shock, the organophosphorus poison and the acute lung injury. Here, the elicitation effect of different elicitors on the production of tropane alkaloids and the molecular mechanism of enzyme genes in the pathway was firstly demonstrated in hairy roots of Anisodus acutangulus. The results showed ethanol, methyl jasmonate and Ag(+) could improve the accumulation of tropane alkaloids up to 1.51, 1.13 and 1.08 times after 24 h treatment, respectively (P < 0.05), whereas salicylic acid decreased the average content of tropane alkaloids. Furthermore, expression profile analysis results revealed that up-regulation of hyoscyamine-6b-hydroxylase (AaH6H) and little regulation of tropinone reducase II (AaTR2) elicited by ethanol, increased expression of putrescine N-methyltransferase I (AaPMT1) elicited by Ag(+), elevated expression of tropinone reducase I (AaTR1) elicited by methyl jasmonate, respectively, resulted in tropane alkaloids improvement. Our results showed that hairy root culture of A. acutangulus in combination with elicitors was a promising way for production of tropane alkaloids in the future.
[show abstract][hide abstract] ABSTRACT: Zero-dimensional nanostructures such as ZnO#ZnS QDs heterojunctures (QDHJs) are green nanoparticles and have gained a tremendous amount of attention. However, very little information is available on the effects of these heterojunctures on the transportation of drugs in blood. Herein, stilbenes were studied for their affinities for common bovine plasma proteins (CBPP) in the presence and absence of QDHJs with different diameters. The affinities of QDHJs for CBPP improved with increasing QDHJs size. QDHJs improved the affinities of resveratrol and polydatin for CBPP by 14.74% to 22.36% and 12.56% to 21.34% depending on the size of QDHJs. The number of binding sites (n) between resveratrol and polydatin for CBPP in the presence of QDHJs were 1.04 ± 0.03 and 1.06 ± 0.04, which were obviously higher than those in the absence of QDHJs (n = 0.89 and 0.92). QDHJs in blood will decrease the free concentration of stilbenes and weaken their pharmacological effects.
[show abstract][hide abstract] ABSTRACT: Recently, investigations of biological toxicity of cadmium QDs and their toxic interaction with plasma proteins have attracted great interest. In this work, flavonoids were studied for the affinities for human serum albumin (HSA) in the presence and absence of CdTe G-QDs by fluorescence quenching method. CdTe G-QDs obviously enhanced the binding affinities of kaempferol, genistein and biochanin A by 3.78 to 154.88 times depending on the QDs concentration. However, the affinity of kaempferide for HSA was slightly weakened in the presence of G-QDs. The non-methylated flavonoids were more sensitive to G-QDs than their methylated forms. The affinities of kaempferide and kaempferol for HSA at first were slightly improved and then obviously decreased with increasing G-QDs concentration. For genistein, the affinities for HSA decreased with increasing G-QDs concentration. However, the G-QDs concentration showed no obvious effect on the affinity of biochanin A. The binding affinities of flavonoids for HSA improved with increasing QDs size.
[show abstract][hide abstract] ABSTRACT: As more and more genetically modified (GM) crops are approved for commercialization and planting, the development of quick and on-spot methods for GM crops and their derivates is required. Herein, we established the polymerase chain reaction and agarose gel electrophoresis-free system for the identification of seven GM maize events (DAS-59122-7, T25, BT176, TC1507, MON810, BT11, and MON863) employing a loop-mediated isothermal amplification (LAMP) technique. The LAMP assay was performed using a set of four specific primers at 60-65 °C in less than 40 min, and the results were observed by direct visual observation. In these developed assays, the specificity targeted at each GM maize event based on the event-specific sequence was well confirmed, and the limits of detection were as low as four copies of maize haploid genomic DNA with an exception of 40 copies for MON810 assay. Furthermore, these developed assays were successfully used to test six practical samples with different GM maize events and contents (ranged from 0.0 to 2.0%). All of the results indicated that the established event-specific visual LAMP assays are more convenient, rapid, and low-cost for GM maize routine analysis.
Journal of Agricultural and Food Chemistry 05/2011; 59(11):5914-8. · 2.91 Impact Factor
[show abstract][hide abstract] ABSTRACT: The relationship between the structural properties of natural polyphenols and their affinities for α-amylase were investigated by fluorescence titration analysis. The binding process with α-amylase was strongly influenced by the structural differences of the compounds under study. For instance, the methylation of the hydroxyl group in flavonoids increased their binding affinities for α-amylase by 2.14 to 7.76 times. The hydroxylation on rings A, B, and C of flavonoids also significantly affected their affinities for α-amylase. The glycosylation of isoflavones and flavanones reduced their affinities for α-amylase and the glycosylation of flavones and flavonols enhanced their affinities for α-amylase. Hydrogenation of the C2=C3 double bond of flavonoids decreased the binding affinities. The galloylated catechins had higher binding affinities with α-amylase than non-galloylated catechins and the pyrogallol-type catechins had higher affinities than the catechol-type catechins. The presence of the galloyl moiety is the most decisive factor. The glycosylation of resveratrol decreased its affinity for α-amylase. The esterification of gallic acid significantly reduced the affinity for α-amylase. The binding interaction between polyphenols and α-amylase was mainly caused by hydrophobic forces.
[show abstract][hide abstract] ABSTRACT: Hyoscyamine 6β-hydroxylase (H6H; EC 188.8.131.52) converts hyoscyamine to scopolamine in the last step of scopolamine biosynthetic pathway. The gene encoding H6H in Anisodus acutangulus was cloned and expressed in Escherichia coli and the recombinant proteins fused with His-tag or GST-tag at its N-terminal were purified and then confirmed by Western bolt analysis. The biofunctional assay revealed that the His-AaH6H and GST-AaH6H converted hyoscyamine (40 mg/l) to scopolamine at 32 and 31 mg/l, respectively. This is the first report on AaH6H expression, purification and functional characterization facilitates further genetic improvement of scopolamine yield in A. acutangulus.
[show abstract][hide abstract] ABSTRACT: The molecular property-affinity relationship of dietary flavonoids for bovine gamma-globulin (γ-globulin) was investigated by fluorescence titration analysis. The quenching effects of flavonoids on γ-globulin fluorescence depended on the structures of flavonoids. The magnitudes of binding constants between flavonoids and γ-globulin were within the range of 10(3)-10(5) L mol(-1). These data were much smaller than the affinities between flavonoids and purified bovine and human serum albumins. The affinities of flavonoids for γ-globulin were strongly influenced by the structural differences of the compounds under study. The affinities for γ-globulin decreased with increasing partition coefficients and increased with increasing hydrogen bond acceptor numbers of flavonoids, which suggested that the binding interaction was mainly caused by hydrogen bond forces.
[show abstract][hide abstract] ABSTRACT: Zero-dimensional nanostructures are green nanomaterials that have recently attracted increasing attention. However, very little information is available on whether or not these heterostructures affect drug transport in blood. In current work, flavonoid aglycones were studied for their affinities for bovine serum albumin (BSA) in the presence and absence of zinc oxide-zinc sulfide quantum dots (ZnO-ZnS QDs) in vitro. The fluorescence intensity of BSA decreased remarkably with increasing concentration of ZnO-ZnS QDs, resulting in an obvious red-shift of the maximum emission of BSA from 340 to 348 nm. The magnitudes of binding constants in the presence of QDs ranged from 10(4) to 10(6) L/mol, and the number of binding sites per BSA molecule (n) was determined as 1.12 ± 0.17. Although ZnO-ZnS QDs significantly increased the affinities for BSA of myricetin, luteolin, gallocatechin gallate, tectorigenin, and formononetin, they barely affected the binding affinities of flavone, (-)-epicatechin gallate, and quercetin. FROM THE CLINICAL EDITOR: Serum albumins are major transport proteins in blood that reversibly bind fatty acids, amino acids, drugs, and inorganic ions, which interactions have important effects on the distribution, free concentration, and metabolism of drugs in blood. In this research nine flavonoid aglycones were studied for their affinities for bovine serum albumin (BSA). Interestingly it was found that presence of ZnO-ZnS QDs significantly increased the affinities of BSA for several of these aglycones.
Nanomedicine: nanotechnology, biology, and medicine 02/2011; 7(6):850-8. · 6.93 Impact Factor
[show abstract][hide abstract] ABSTRACT: Tanshinone is a group of active diterpenes widely used in treatment of cardiovascular diseases. Here, we report the introduction of genes encoding 3-hydroxy-3-methylglutaryl CoA reductase (HMGR), 1-deoxy-D-xylulose-5-phosphate synthase (DXS) and geranylgeranyl diphosphate synthase (GGPPS) involved in tanshinone biosynthesis into Salvia miltiorrhiza hairy roots by Agrobacterium-mediated gene transfer technology. Overexpression of SmGGPPS and/or SmHMGR as well as SmDXS in transgenic hairy root lines can significantly enhance the production of tanshinone to levels higher than that of the control (P<0.05). SmDXS showed much more powerful pushing effect than SmHMGR in tanshinone production, while SmGGPPS plays a more important role in stimulating tanshinone accumulation than the upstream enzyme SmHMGR or SmDXS in S. miltiorrhiza. Co-expression of SmHMGR and SmGGPPS resulted in highest production of tanshinone (about 2.727 mg/g dw) in line HG9, which was about 4.74-fold higher than that of the control (0.475 mg/g dw). All the tested transgenic hairy root lines showed higher antioxidant activity than the control. To our knowledge, this is the first report on enhancement of tanshinone content and antioxidant activity achieved through metabolic engineering of hairy roots by push-pull strategy in S. miltiorrhiza.
[show abstract][hide abstract] ABSTRACT: Salvia miltiorrhiza Bunge, called Dan shen in China, is a well-known traditional Chinese herb and has been used widely for the treatment of cardiovascular diseases due to its better performance and fewer side effects as confirmed in the long-time clinical use. Tanshinones, one class of lipid-soluble diterpene quinones from S. miltiorrhiza, were found to exhibit various pharmacological activities such as anti-oxidative, anti-inflammatory and anti-tumor properties. Due to the great importance of tanshinone and to its complex chemical nature as well as low content in plants, many efforts have been made to improve tanshinone production including hairy root culture, elicitor treatment and genetic engineering with new advance in recent years. Pharmacological activities of tanshinones and metabolic regulation of tanshinones biosynthesis in S. miltiorrhiza were reviewed in this paper.
Journal of Medicinal Plants Research. 01/2011; 4:2591-2597.
[show abstract][hide abstract] ABSTRACT: The effect of introduction of the Zephyranthes grandiflora agglutinin gene (zga) to tobacco on its anti-pest ability for peach-potato aphids was investigated. PCR analysis confirmed that the zga gene was integrated into the plant genome. The results from semi-quantitative RT-PCR and real-time PCR assays revealed that
the zga gene was expressed at various levels in the transgenic plants. A bioassay with aphids indicated that transgenic plants conferred
enhanced resistance to aphids. Compared with the controls, the average number of aphids fed with transgenic plants during
a 20-day assay evidently decreased by 70.4% in leaf disc bioassay and 77.9% in whole plant bioassay. The average number of
nymph was significantly reduced by 36.4% on zga-expressing plants in leaf disc bioassay and 35.6% in whole plant bioassay. The report indicated that the introduction of
zga gene to tobacco plants is a useful method to improve its anti-pest ability for aphids.
Zephyranthes grandiflora agglutinin–Peach-potato aphid–Transgenic tobacco
Acta Physiologiae Plantarum 01/2011; 33(5):2003-2010. · 1.31 Impact Factor
[show abstract][hide abstract] ABSTRACT: Tropane alkaloids (TA) including anisodamine, anisodine, hyoscyamine and scopolamine are a group of important anticholinergic drugs with rapidly increasing market demand, so it is significant to improve TA production by biotechnological approaches. Putrescine N-methyltransferase (PMT) was considered as the first rate-limiting upstream enzyme while tropinone reductase I (TRI) was an important branch-controlling enzyme involved in TA biosynthesis. However, there is no report on simultaneous introduction of PMT and TRI genes into any TA-producing plant including Anisodus acutangulus (A. acutangulus), which is a Solanaceous perennial plant that is endemic to China and is an attractive resource plant for production of TA.
In this study, 21 AaPMT and AaTRI double gene transformed lines (PT lines), 9 AaPMT single gene transformed lines (P lines) and 5 AaTRI single gene transformed lines (T lines) were generated. RT-PCR and real-time fluorescence quantitative analysis results revealed that total AaPMT (AaPMT T) and total AaTRI (AaTRI T) gene transcripts in transgenic PT, P and T lines showed higher expression levels than native AaPMT (AaPMT E) and AaTRI (AaTRI E) gene transcripts. As compared to the control and single gene transformed lines (P or T lines), PT transgenic hairy root lines produced significantly higher levels of TA. The highest yield of TA was detected as 8.104 mg/g dw in line PT18, which was 8.66, 4.04, and 3.11-times higher than those of the control (0.935 mg/g dw), P3 (highest in P lines, 2.004 mg/g dw) and T12 (highest in T lines, 2.604 mg/g dw), respectively. All the tested samples were found to possess strong radical scavenging capacity, which were similar to control.
In the present study, the co-expression of AaPMT and AaTRI genes in A. acutangulus hairy roots significantly improved the yields of TA and showed higher antioxidant activity than control because of higher total TA content, which is the first report on simultaneous introduction of PMT and TRI genes into TA-producing plant by biotechnological approaches.