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American Journal of Plant Sciences 2014年第24期5卷 3519-3525页

作者： venkata sai prakash chaturvedula Wisdom Natural Brands Gilbert AZ USA

From the commercial extract of the leaves of Stevia rebaudiana Bertoni, a new minor ent-kaurane diterpene glycoside having five β-D-glucopyranosyl units has been isolated. The chemical structure of the new compound was characterized as 13-[(2-O-β-D-glucopyranosyl-β-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid-(2-O-β-D-glucopyranosyl-6-O-β-D-glucopyranosyl-β-D-glucopyranosyl) ester (1) on the basis of extensive 1D (1H & 13C) and 2D NMR (TOCSY, HMQC, and HMBC), and High Resolution (HR) mass spectroscopic data as well as hydrolysis studies.

关键词： Stevia rebaudiana Compositae Asteraceae Diterpenoid Glycoside Spectral Data Hydrolysis Studies Structure Characterization

Reversed-Phase HPLC Analysis of Steviol Glycosides Isolated from Stevia rebaudiana Bertoni

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Food and Nutrition Sciences 2014年第17期5卷 1711-1716页

作者： venkata sai prakash chaturvedula Julian Zamora Natural Products Research Group Wisdom Natural Brands Gilbert USA

High Performance Liquid Chromatography (HPLC) experiments have been performed on nine steviol glycosides namely rebaudioside A, steviolbioside, stevioside, rubusoside, rebaudioside B, rebaudioside C, rebaudioside D, rebaudioside F, and dulcoside A isolated from the leaves of Stevia rebaudiana using Reversed-Phase (RP) column. Using RP-HPLC method, the individual retention times for nine naturally occurring ent-kaurane diterpene glycosides of S. rebaudiana reported in JECFA have been determined at four different temperatures: 20℃, 40℃, 60℃, and 79℃. Also, calculated the relative retention times of the eight steviol glycosides steviolbioside, stevioside, rubusoside, rebaudioside B, rebaudioside C, rebaudioside D, rebaudioside F, and dulcoside A against the major steviol glycoside rebaudioside A. HPLC results suggested that temperatures 40℃ and 60℃ would be ideal conditions for better separation of steviol glycosides.

关键词： Stevia rebaudiana Asteraceae Diterpene Glycosides Reversed-Phase HPLC Analysis Retention and Relative Retention Times

A New Penta β-D-Glucopyranosyl Diterpene from Stevia rebaudiana

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International Journal of Organic Chemistry 2017年第2期7卷 91-98页

作者： venkata sai prakash chaturvedula Srinivasa Rao Meneni Wisdom Natural Brands Natural Products Research Group Gilbert AZ USA

A new steviol diterpene glycoside, 13-[(2-O-β-D-glucopyranosyl-β-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid-{2-O-[6-O-β-D-glucopyranosyl)-β-D-glucopyranosyl]-β-D-glucopyranosyl} ester (1) has been isolated from the commercial extract of the leaves of Stevia rebaudi-ana Bertoni. Structure of the new compound has been established on the basis of extensive NMR spectroscopy (1H &13C, TOCSY, HMQC, and HMBC) and High Resolution (HR) mass spectroscopic data as well as enzymatic and acid hydrolysis studies.

关键词： Stevia rebaudiana Compositae Asteraceae Diterpenoid Glycoside Structure Characterization Spectral Data Hydrolysis Studies

IR Spectral Analysis of Diterpene Glycosides Isolated from Stevia rebaudiana

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Food and Nutrition Sciences 2012年第10期3卷 1467-1471页

作者： venkata sai prakash chaturvedula Christopher Mubarak Indra prakash Analytical Chemistry Department The Coca-Cola Company Global Research and Development One Coca-Cola Plaza Atlanta GA 30313 USA Organic Chemistry Department The Coca-Cola Company Global Research and Development One Coca-Cola Plaza Atlanta GA 30313 USA

The objective is to identify the Infra-Red (IR) spectral analysis of the diterpene glycosides present in the commercial extracts of Stevia rebaudiana was achieved by PerkinElmer Spectrum 400 Fourier Transform (FT) spectrometer employing a PerkinElmer Universal Attenuated Total Reflection (ATR) accessory. Using this technique the IR spectral pattern of 15 steviol glycosides which belongs to three different classes of ent-kaurane diterpene glycosides namely ent-13-hydroxykaur-16-en-19-oic acid, ent-13-hydroxykaur-15-en-19-oic acid, and 13-methyl-16-oxo-17-norent- kauran-19-oic acid were identified. From the wave numbers found for all 15 steviol glycosides, it was observed that that though there are differences in the number of sugar units, nature of sugar units, and their attachments;there are not any notable differences in the IR values.

关键词： Stevia rebaudiana Diterpene Glycosides IR Spectral Data

NMR Spectral Analysis and Hydrolysis Studies of Rebaudioside N, a Minor Steviol Glycoside of Stevia rebaudianaBertoni

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Food and Nutrition Sciences 2013年第10期4卷 1004-1008页

作者： venkata sai prakash chaturvedula Steven Chen Oliver Yu Guohong Mao Natural Ingredient Development Blue California Rancho Santa Margarita USA Natural Ingredient Development Blue California Rancho Santa Margarita USA.

The complete proton and carbon NMR spectral assignments of a diterpene glycoside isolated from the commercial extract of the leaves of Stevia rebaudiana Bertoni, 13-[(2-O-β-D-glucopyranosyl-3-O-β-D-glucopyranosyl-β-D-glucopyranosyl)oxy] entkaur-16-en-19-oic acid-[(2-O-α-L-rhamnopyranosyl-3-O-β-D-glucopyranosyl-β-D-glucopyranosyl) ester] (1);also known as rebaudioside N, was achieved by the extensive 1D and 2D NMR (1H and 13C, COSY, HMQC, HMBC) as well as mass spectral data. Further, hydrolysis studies were performed on rebaudioside N using acid and enzymatic studies to identify aglycone and sugar residues in its structure.

关键词： Stevia rebaudiana Diterpene Glycoside Isolation Structure Elucidation Spectral Data Hydrolysis Studies

Enzymatic Synthesis and Structural Characterization of Rebaudioside D3, a Minor Steviol Glycoside of Stevia rebaudianaBertoni

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American Journal of Plant Sciences 2017年第3期8卷 441-450页

作者： Guohong Mao venkata sai prakash chaturvedula Jacob Edward Vick Oliver Yu Conagen Inc. Bedford MA USA Blue California Rancho Santa Margarita CA USA Wuxi New Way Biotechnology Ltd. Wuxi China

Rebaudioside D3, a novel steviol glycoside, is produced by specific UDP-glycosyltransferase of rebaudioside E, a minor steviol glycoside of Stevia rebaudiana Bertoni. The complete proton and carbon NMR spectral assignments of rebaudioside D3, 13-[(2-O-β-D-glucopyranosyl-6-O-β-D-glucopyranosyl-β-D-glucopyranosyl) oxy] ent-kaur-16-en-19-oic acid-(2-O-β-D-glucopyranosyl-β-D-glucopyranosyl) ester, was achieved by the extensive 1D and 2D NMR (1H and 13C, TOCSY, HMQC, HMBC) as well as mass spectral data. Further, hydrolysis studies were performed on rebaudioside D3 using acid and enzymatic studies to identify aglycone and sugar residues in its structure. Rebaudioside D3 is detected in the commercial extract of the leaves of Stevia rebaudiana by LC-MS analysis, suggesting rebaudioside D3 is a natural steviol glycoside.

关键词： Stevia rebaudiana Diterpene Glycoside Structure Characterization Spectral Data LC-MS

Surveying the genomic landscape of silage-quality traits in maize(Zea mays L.)

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The Crop Journal 2023年第6期11卷 1893-1901页

作者： Jatin Sharma Shubham Sharma Krishna sai Karnatam Om prakash Raigar Chayanika Lahkar Dinesh Kumar saini Sushil Kumar Alla Singh Abhijit Kumar Das Priti Sharma Ramesh Kumar Department of Plant Breeding and Genetics Punjab Agricultural UniversityLudhianaPunjab 141004India School of Agricultural Biotechnology Punjab Agricultural UniversityLudhianaPunjab 141004India ICAR-Indian Institute of Maize Research LudhianaPunjab 141004India Department of Plant and Soil Science Texas Tech UniversityLubbockTX 79409-2122USA

Despite the longstanding importance of silage as a critical feed source for ruminants,its quality improvement has been largely *** numerous quantitative trait loci(QTL)and genes affecting silage quality in maize have been reported,only a few have been effectively incorporated into breeding *** this gap,the present study undertook a comprehensive meta-QTL(MQTL)analysis involving 523 QTL associated with silage-quality traits collected from 14 published *** the 523 QTL,405 were projected onto a consensus map comprising 62,424 genetic markers,resulting in the identification of 60 MQTL and eight *** average confidence interval(CI)of the MQTL was 3.9-fold smaller than that of the source *** of the 60 identified MQTL were classified as breeder’s MQTL owing to their small CIs,involvement of more QTL,and large contribution to phenotypic ***-third of the MQTL co-localized with DNA marker-trait associations identified in previous genomewide association mapping studies.A set of 78 high-confidence candidate genes influencing silage quality were identified in the MQTL *** genes and associated markers may advance marker-assisted breeding for maize silage quality.

关键词： Meta-QTL Silage quality Maize GWAS Candidate genes

Joining of AZ91 Mg alloy and Al6063 alloy sheets by friction stir welding

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Journal of Magnesium and Alloys 2018年第1期6卷 71-76页

作者： B.Lakshmana Prasad G.Neelaiah M.Gopi Krishna S.V.V.Ramana K.sai prakash G.Sarika G.Pradeep Kumar Reddy Ravikumar Dumpala B.Ratna Sunil Department of Mechanical Engineering Rajiv Gandhi University of Knowledge Technologies(AP-IIIT)Nuzvid 520201India Department of Mechanical Engineering Vignana Bharathi Institute of TechnologyHyderabad 501301India Department of Mechanical Engineering Visvesvaraya National Institute of TechnologyNagpur 440010India

In the present work,the effect of process parameters on joining of AZ91 Mg alloy and Al6063 aluminum alloy sheets during friction stir welding(FSP)was studied.A successful joint was achieved at 1100 *** rotational speed and 25 mm/min tool travel *** of tool rotational speed and tool travel speed has observed a profound effect on the material flow mechanisms at the nugget *** the microstructural studies,the joint formation was observed as mainly due to mechanical mixing of the *** level of metallurgical continuity at the nugget zone was observed as poor and a sharp interface at the joint was *** microhardness measurements across the weld joint also revealed the lack of establishment of a perfect metallurgical bonding.X-ray diffraction analysis of weld zone showed presence of both magnesium and *** from the preliminary observations,it can be understood that the joining of AZ91 Mg alloy and Al6063 alloy can be achieved by FSP;however,complex issues in material mixing still need further investigations.

关键词： Friction stir welding Dissimilar joints Magnesium Aluminum Nugget zone

Crystal and Molecular Structure of 2-Amino-3-Ethyl Carboxamido-4-Metyl-5-Carboxy Ethyl Thiophene

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Crystal Structure Theory and Applications 2012年第3期1卷 92-96页

作者： Dhananjay Dey Venugopal prakash Vasu Janardhanan Saravanan Deepak Chopra Department of Chemistry Indian Institute of Science Education and Research Bhopal India PES College of Pharmacy Bangalore India Shirdi sai Engineering College Bangalore India Vivekananda Degree College Bangalore India

The crystal and molecular structure of 2-Amino-3-ethyl carboxamido-4-methyl-5-carboxy ethyl thiophene (C11H16N2O3S) has been investigated from single crystal X-ray diffraction data. The primary focus is to investigate the molecular geometry of this compound in the solid state along with the associated inter and intra-molecular hydrogen bonding and related weak interactions present in this molecule. This compound crystallizes in the monoclinic space group P21/c with cell parameters, a = 8.1344(3) , b = 13.7392(4) , c = 11.4704(4) , β = 100.769(2), V = 1259.36 (7) 3, D = 1.352 g·cm–3, Z = 4. The molecular geometry is stabilized by intra-molecular N-H…O=C and C-H…O interactions along with intramolecular C-H…N and C-H…O interactions which contribute towards the stability of the crystal packing.

关键词： Crystal Molecular Conformation Intermolecular Interactions Spectroscopy Diffraction