The Experts below are selected from a list of 93 Experts worldwide ranked by ideXlab platform
Yvan Rahbé - One of the best experts on this subject based on the ideXlab platform.
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Broad screening of the legume family for variability in seed insecticidal activities and for the occurrence of the A1b-like knottin peptide entomotoxins.
Phytochemistry, 2007Co-Authors: Sandrine Louis, Gabrielle Duport, Ousmane Diol, Isabelle Rahioui, Hubert Charles, Frederic Gressent, Bernard Delobel, Yvan RahbéAbstract:Pea albumin 1b (PA1b) is a small sulphur-rich peptide from pea seeds, also named leginsulin because of the binding characteristics of its soybean orthologue. Its insecticidal properties were discovered more recently. By using a combination of molecular, biochemical and specific insect bioassays on seed extracts, we characterised genes from numerous Papilionoideae, but not from Caesalpinioideae or Mimosoideae, although the last group harboured species with partially positive cues (homologous biological activities). The A1b defence peptide family, therefore, appears to have evolved relatively late in the legume lineage, maybe from the sophoroid group (e.g. Styphnolobium japonicum). However, unambiguous sequence information is restricted to a group of tribes within the subfamily Papilionoideae (Psoraleae, Millettieae, Desmodieae, Hedysareae, Phaseoleae, Vicieae, and the now clearly polyphyletic "Trifolieae" and "Galegeae"). Recent diversification by gene duplications has occurred in many species, or longer ago in some lineages (Medicago truncatula), as well as probable gene or expression losses at different taxonomic levels (Loteae, Vigna subterranea).
Nigel C Veitch - One of the best experts on this subject based on the ideXlab platform.
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flavonol tetraglycosides from fruits of Styphnolobium japonicum leguminosae and the authentication of fructus sophorae and flos sophorae
Phytochemistry, 2009Co-Authors: Geoffrey C Kite, Nigel C Veitch, Martha E Boalch, Gwilym P Lewis, Christine Leon, Monique S J SimmondsAbstract:Abstract The dried fruits and seeds of Styphnolobium japonicum (L.) Schott (syn. Sophora japonica L.) are used in traditional Chinese medicine and known as Fructus Sophorae or Huai Jiao. The major flavonoids in these fruits and seeds were studied by LC–MS and other spectroscopic techniques to aid the chemical authentication of Fructus Sophorae. Among the flavonoids were two previously unreported kaempferol glycosides: kaempferol 3-O-β-glucopyranosyl(1 → 2)-β-galactopyranoside-7-O-α-rhamnopyranoside and kaempferol 3-O-β-xylopyranosyl(1 → 3)-α-rhamnopyranosyl(1 → 6)[β-glucopyranosyl(1 → 2)]-β-glucopyranoside, the structures of which were determined by NMR. Two further tetraglycosides were identified for the first time in S. japonicum as kaempferol 3-O-β-glucopyranosyl(1 → 2)[α-rhamnopyranosyl(1 → 6)]-β-glucopyranoside-7-O-α-rhamnopyranoside and kaempferol 3-O-β-glucopyranosyl(1 → 2)[α-rhamnopyranosyl(1 → 6)]-β-galactopyranoside-7-O-α-rhamnopyranoside; the latter was the main flavonoid in mature seeds. The chromatographic profiles of 27 recorded flavonoids were relatively consistent among fruits of similar ages collected from five trees of S. japonicum, and those of maturing unripe and ripe fruits were similar to a market sample of Fructus Sophorae, and thus provide useful markers for authentication of this herbal ingredient. The flower buds (Huai Mi) and flowers (Huai Hua) of S. japonicum (collectively Flos Sophorae) contained rutin as the main flavonoid and lacked the flavone glycosides that were present in flower buds and flowers of Sophora flavescens Ait., reported to be occasional substitutes for Flos Sophorae. The single major flavonoid in fruits of S. flavescens was determined as 3′-hydroxydaidzein.
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flavonol tetraglycosides and other constituents from leaves of Styphnolobium japonicum leguminosae and related taxa
Phytochemistry, 2007Co-Authors: Geoffrey C Kite, Charlotte A Stoneham, Nigel C VeitchAbstract:Abstract Two flavonol tetraglycosides comprising a trisaccharide at C-3 and a monosaccharide at C-7 were isolated from the leaves of Styphnolobium japonicum (L.) Schott and characterised as the 3- O -α-rhamnopyranosyl(1 → 2)[α-rhamnopyranosyl(1 → 6)]-β-glucopyranoside-7- O -α-rhamnopyranosides of quercetin and kaempferol. The 3- O -α-rhamnopyranosyl(1 → 2)[α-rhamnopyranosyl(1 → 6)]-β-galactopyranoside-7- O -α-rhamnopyranoside of kaempferol, the 3- O -α-rhamnopyranosyl(1 → 2)[α-rhamnopyranosyl(1 → 6)]-β-glucopyranosides of kaempferol and quercetin and the 3- O -α-rhamnopyranosyl(1 → 2)[α-rhamnopyranosyl(1 → 6)]-β-galactopyranoside of kaempferol were also obtained from this species for the first time. Some or all of these flavonol tetra- and triglycosides were detected in 17 of 18 specimens of S. japonicum examined from living and herbarium material, although the most abundant flavonoid in the leaves was generally quercetin 3- O -α-rhamnopyranosyl(1 → 6)-β-glucopyranoside (rutin). The triglycosides, but not the tetraglycosides, were detected in herbarium specimens of Styphnolobium burseroides M. Sousa, Rudd & Medrano and Styphnolobium monteviridis M. Sousa & Rudd, but specimens of Styphnolobium affine (Torrey & A. Gray) Walp. contained a different profile of flavonol glycosides. The flavonol tetra- and triglycosides of S. japonicum were also present in leaves of Cladrastis kentukea (Dum. Cours.) Rudd, a representative of a genus placed close to Styphnolobium in current molecular phylogenies. An additional constituent obtained from leaves of Styphnolobium japonicum was identified as the maltol derivative, 3-hydroxy-2-methyl-4 H -pyran-4-one 3- O -(4′- O - p -coumaroyl-6′- O -(3-hydroxy-3-methylglutaroyl))-β-glucopyranoside.
Geoffrey C Kite - One of the best experts on this subject based on the ideXlab platform.
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flavonol tetraglycosides from fruits of Styphnolobium japonicum leguminosae and the authentication of fructus sophorae and flos sophorae
Phytochemistry, 2009Co-Authors: Geoffrey C Kite, Nigel C Veitch, Martha E Boalch, Gwilym P Lewis, Christine Leon, Monique S J SimmondsAbstract:Abstract The dried fruits and seeds of Styphnolobium japonicum (L.) Schott (syn. Sophora japonica L.) are used in traditional Chinese medicine and known as Fructus Sophorae or Huai Jiao. The major flavonoids in these fruits and seeds were studied by LC–MS and other spectroscopic techniques to aid the chemical authentication of Fructus Sophorae. Among the flavonoids were two previously unreported kaempferol glycosides: kaempferol 3-O-β-glucopyranosyl(1 → 2)-β-galactopyranoside-7-O-α-rhamnopyranoside and kaempferol 3-O-β-xylopyranosyl(1 → 3)-α-rhamnopyranosyl(1 → 6)[β-glucopyranosyl(1 → 2)]-β-glucopyranoside, the structures of which were determined by NMR. Two further tetraglycosides were identified for the first time in S. japonicum as kaempferol 3-O-β-glucopyranosyl(1 → 2)[α-rhamnopyranosyl(1 → 6)]-β-glucopyranoside-7-O-α-rhamnopyranoside and kaempferol 3-O-β-glucopyranosyl(1 → 2)[α-rhamnopyranosyl(1 → 6)]-β-galactopyranoside-7-O-α-rhamnopyranoside; the latter was the main flavonoid in mature seeds. The chromatographic profiles of 27 recorded flavonoids were relatively consistent among fruits of similar ages collected from five trees of S. japonicum, and those of maturing unripe and ripe fruits were similar to a market sample of Fructus Sophorae, and thus provide useful markers for authentication of this herbal ingredient. The flower buds (Huai Mi) and flowers (Huai Hua) of S. japonicum (collectively Flos Sophorae) contained rutin as the main flavonoid and lacked the flavone glycosides that were present in flower buds and flowers of Sophora flavescens Ait., reported to be occasional substitutes for Flos Sophorae. The single major flavonoid in fruits of S. flavescens was determined as 3′-hydroxydaidzein.
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flavonol tetraglycosides and other constituents from leaves of Styphnolobium japonicum leguminosae and related taxa
Phytochemistry, 2007Co-Authors: Geoffrey C Kite, Charlotte A Stoneham, Nigel C VeitchAbstract:Abstract Two flavonol tetraglycosides comprising a trisaccharide at C-3 and a monosaccharide at C-7 were isolated from the leaves of Styphnolobium japonicum (L.) Schott and characterised as the 3- O -α-rhamnopyranosyl(1 → 2)[α-rhamnopyranosyl(1 → 6)]-β-glucopyranoside-7- O -α-rhamnopyranosides of quercetin and kaempferol. The 3- O -α-rhamnopyranosyl(1 → 2)[α-rhamnopyranosyl(1 → 6)]-β-galactopyranoside-7- O -α-rhamnopyranoside of kaempferol, the 3- O -α-rhamnopyranosyl(1 → 2)[α-rhamnopyranosyl(1 → 6)]-β-glucopyranosides of kaempferol and quercetin and the 3- O -α-rhamnopyranosyl(1 → 2)[α-rhamnopyranosyl(1 → 6)]-β-galactopyranoside of kaempferol were also obtained from this species for the first time. Some or all of these flavonol tetra- and triglycosides were detected in 17 of 18 specimens of S. japonicum examined from living and herbarium material, although the most abundant flavonoid in the leaves was generally quercetin 3- O -α-rhamnopyranosyl(1 → 6)-β-glucopyranoside (rutin). The triglycosides, but not the tetraglycosides, were detected in herbarium specimens of Styphnolobium burseroides M. Sousa, Rudd & Medrano and Styphnolobium monteviridis M. Sousa & Rudd, but specimens of Styphnolobium affine (Torrey & A. Gray) Walp. contained a different profile of flavonol glycosides. The flavonol tetra- and triglycosides of S. japonicum were also present in leaves of Cladrastis kentukea (Dum. Cours.) Rudd, a representative of a genus placed close to Styphnolobium in current molecular phylogenies. An additional constituent obtained from leaves of Styphnolobium japonicum was identified as the maltol derivative, 3-hydroxy-2-methyl-4 H -pyran-4-one 3- O -(4′- O - p -coumaroyl-6′- O -(3-hydroxy-3-methylglutaroyl))-β-glucopyranoside.
Ikhlas A. Khan - One of the best experts on this subject based on the ideXlab platform.
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Identification of Ginkgo biloba supplements adulteration using high performance thin layer chromatography and ultra high performance liquid chromatography-diode array detector-quadrupole time of flight-mass spectrometry
Analytical and Bioanalytical Chemistry, 2015Co-Authors: Bharathi Avula, Satyanarayanaraju Sagi, Stefan Gafner, Roy Upton, Yan-hong Wang, Mei Wang, Ikhlas A. KhanAbstract:Ginkgo biloba is one of the most widely sold herbal supplements and medicines in the world. Its popularity stems from having a positive effect on memory and the circulatory system in clinical studies. As ginkgo popularity increased, non-proprietary extracts were introduced claiming to have a similar phytochemical profile as the clinically tested extracts. The standardized commercial extracts of G. biloba leaf used in ginkgo supplements contain not less than 6 % sesquiterpene lactones and 24 % flavonol glycosides. While sesquiterpene lactones are unique constituents of ginkgo leaf, the flavonol glycosides are found in many other botanical extracts. Being a high value botanical, low quality ginkgo extracts may be subjected to adulteration with flavonoids to meet the requirement of 24 % flavonol glycosides. Chemical analysis by ultra high performance liquid chromatography-mass spectrometry revealed that adulteration of ginkgo leaf extracts in many of these products is common, the naturally flavonol glycoside-rich extract being spiked with pure flavonoids or extracts made from another flavonoid-rich material, such as the fruit/flower of Japanese sophora ( Styphnolobium japonicum ), which also contains the isoflavone genistein. Recently, genistein has been proposed as an analytical marker for the detection of adulteration of ginkgo extracts with S. japonicum . This study confirms that botanically authenticated G. biloba leaf and extracts made therefrom do not contain genistein, and the presence of which even in trace amounts is suggestive of adulteration. In addition to the mass spectrometric approach, a high performance thin layer chromatography method was developed as a fast and economic method for chemical fingerprint analysis of ginkgo samples.
Sandrine Louis - One of the best experts on this subject based on the ideXlab platform.
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Broad screening of the legume family for variability in seed insecticidal activities and for the occurrence of the A1b-like knottin peptide entomotoxins.
Phytochemistry, 2007Co-Authors: Sandrine Louis, Gabrielle Duport, Ousmane Diol, Isabelle Rahioui, Hubert Charles, Frederic Gressent, Bernard Delobel, Yvan RahbéAbstract:Pea albumin 1b (PA1b) is a small sulphur-rich peptide from pea seeds, also named leginsulin because of the binding characteristics of its soybean orthologue. Its insecticidal properties were discovered more recently. By using a combination of molecular, biochemical and specific insect bioassays on seed extracts, we characterised genes from numerous Papilionoideae, but not from Caesalpinioideae or Mimosoideae, although the last group harboured species with partially positive cues (homologous biological activities). The A1b defence peptide family, therefore, appears to have evolved relatively late in the legume lineage, maybe from the sophoroid group (e.g. Styphnolobium japonicum). However, unambiguous sequence information is restricted to a group of tribes within the subfamily Papilionoideae (Psoraleae, Millettieae, Desmodieae, Hedysareae, Phaseoleae, Vicieae, and the now clearly polyphyletic "Trifolieae" and "Galegeae"). Recent diversification by gene duplications has occurred in many species, or longer ago in some lineages (Medicago truncatula), as well as probable gene or expression losses at different taxonomic levels (Loteae, Vigna subterranea).
