Papers by Ram Kishor Verma
Journal of Radioanalytical and Nuclear Chemistry, 1997
Polyaniline sorbed with microgram quantity of mercury was prepared and its homogeneity and stabil... more Polyaniline sorbed with microgram quantity of mercury was prepared and its homogeneity and stability with respect to mercury was evaluated over a period of time. The volatilisation loss of mercury during and after neutron irradiation was studied. It was found that polyaniline was homogeneous and stable with respect to mercury. No loss of mercury from polyaniline was observed during and after neutron irradiation. Thus polyaniline sorbed with mercury can serve as a good standard for neutron activation analysis of mercury.
Phytochemistry, 2008
a b s t r a c t Three iridoid glycosides 6-O-(3 00 -O-benzoyl)-a-L-rhamnopyranosylcatalpol (1a), ... more a b s t r a c t Three iridoid glycosides 6-O-(3 00 -O-benzoyl)-a-L-rhamnopyranosylcatalpol (1a), 6-O-(3 00 -O-trans-cinnamoyl)-a-L-rhamnopyranosylcatalpol (2a) and 6-O-(3 00 -O-cis-cinnamoyl)-a-L-rhamnopyranosylcatalpol were isolated from aerial parts of Gmelina arborea and structures were elucidated by spectral analysis. Additionally a known iridoid 6-O-(3 00 , 4 00 -O-dibenzoyl)-a-L-rhamnopyranosylcatalpol (4) was also isolated and identified.
Chromatographia, 2008
A quantitative method using silica gel 60F254 high performance thin layer chromatography plates, ... more A quantitative method using silica gel 60F254 high performance thin layer chromatography plates, automated bandwise sample application, and automated visible mode densitometric method has been developed for the determination of 24β-ethylcholesta-5,22E,25-triene-3β-ol (ECTO) in the aerial part of Clerodendrum phlomidis. ECTO was used as a chemical marker for the standardization of C. phlomidis plant extracts. The separation was performed on silica gel 60F254 TLC plates using chloroform-methanol (98.5: 1.5, v/v) as mobile phase. The quantitation of ECTO was carried out using the densitometric reflection/absorption mode at 650 nm after post chromatographic derivatization with anisaldehyde reagent. A precise and accurate quantification can be performed in the linear working concentration range of 150–400 ng band−1 with good correlation (r 2 = 0.996). The method was validated for peak purities, precision, robustness, limit of detection (LOD) and quantitation (LOQ), etc. as per ICH guidelines.
Phytochemical Analysis, 2006
A simple, precise and rapid high-performance thin-layer chromatographic method has been developed... more A simple, precise and rapid high-performance thin-layer chromatographic method has been developed for the estimation of phyllanthin (1) and hypophyllanthin (2), the important lignans of Phyllanthus species, especially Phyllanthus amarus. Separation of 1 and 2 was carried out on silica gel 60 F254 layers eluted with hexane:acetone:ethyl acetate (74:12:8), and the analytes were visualised through colour development with vanillin in concentrated sulphuric acid and ethanol. Scanning and quantification of spots was performed at 580 nm. Recoveries of 1 and 2 were 98.7 and 97.3%, respectively. The method was validated and the peak purities and limits of detection and quantification were determined. Copyright © 2006 John Wiley & Sons, Ltd.
Journal of Liquid Chromatography & Related Technologies, 2009
Abstract Methods based on HPTLC and RP-HPLC with UV detection for rapid quantitative determinatio... more Abstract Methods based on HPTLC and RP-HPLC with UV detection for rapid quantitative determination of two major plant growth promoters in Callicarpa macrophylla, calliterpenone (1) and calliterpenone monoacetate (2) are described. The recoveries of the two ...
Phytochemical Analysis, 1999
A simple, selective, rapid, precise and economical reverse phase HPLC method has been developed f... more A simple, selective, rapid, precise and economical reverse phase HPLC method has been developed for the determination of satranidazole in pharmaceutical formulations. The method was carried out on a isocratic ODS -C18 (250 x 4.6mm i.d.,5 µ) column with a mobile phase consisting of Acetonitrile , 0.025M Ammonium phosphate buffer and 1.0% Ortho phosphoric acid in the ratio 65:35:5 v/v/v) at a flow rate 1.2mL/min. Detection was carried out at 318nm using UV lamp visible detector. The developed method was validated in terms of accuracy, precision, linearity, limit of detection, limit of quantitation and solution stability. The proposed method can be used for the estimation of satranidazole in pharmaceutical formulations.
Chromatographia, 2009
An LC method is developed for the quantitation of rhoifolin in Uraria picta, a plant of high usag... more An LC method is developed for the quantitation of rhoifolin in Uraria picta, a plant of high usage frequency in all Asian traditional systems of medicine. An isocratic RP-LC method using C18 column, UV detection 265 nm and specificity with PDA and MS is speeding up, reliable and comprehensive analysis of rhoifolin in U. picta. Good linearity was obtained in the working range (0.02–0.10 mg mL−1), with correlation coefficients >0.99. LOD and LOQ were 2.33 and 7.69 ng, respectively. The method was validated following international guidelines. The described method can be utilized for assays and stability tests of U. picta extracts as well as Ayurvedic drugs based on Prishniparni.
Phytochemical Analysis, 2004
An attempt has been made to develop a method by which to determine the chemical fingerprint of And... more An attempt has been made to develop a method by which to determine the chemical fingerprint of Andrographis paniculata (Acanthaceae). High-performance thin layer chromatography (HPTLC) was used to analyse hexane, chloroform, methanol and water extracts of leaves of A. paniculata. A computerised densitometer was applied to the two-dimensional spectrographic image analysis of the HPTLC plates. An HPLC equipped with a photodiode array detector was used for the analyses of these different extracts. The analyses showed that andrographolide and neoandrographolide are absent in the hexane extract but are present in greater amounts in the methanol extract as compared with the other extracts. These chromatograms may serve as a chemical fingerprint of the drug A. paniculata for quality control purposes and in the preparation of formulations based on the drug. Copyright © 2004 John Wiley & Sons, Ltd.
Journal of Liquid Chromatography & Related Technologies, 2000
... DV Singh, A. Maithy, RK Verma, MM Gupta and S. Kumar J. Liq. Chromatogr. Relat. Technol., 200... more ... DV Singh, A. Maithy, RK Verma, MM Gupta and S. Kumar J. Liq. Chromatogr. Relat. Technol., 2000, 23(4), 601-607. DOI:10.1081/JLC-100101476. A subscription with the Publisher may be required to access full text content. View at Publisher. ...
Journal of Pharmaceutical and Biomedical Analysis, 2008
A sensitive, selective and robust qualitative and quantitative densitometric high-performance thi... more A sensitive, selective and robust qualitative and quantitative densitometric high-performance thin layer chromatographic method was developed and validated for the determination of iridoid glycoside in the aerial part of Gambhari (Gmelina arborea). Iridoid gycoside 6-O-(2 ,3 -dibenzoyl)-␣-l-rhamnopyranosylcatalpol (IG) was used as a chemical marker for the standardization of G. arborea plant extracts. The separation was performed on aluminum Kieselgel 60F 254 TLC plates using chloroform-methanol as mobile phase. The quantitation of IG was carried out using the densitometric reflection/absorption mode at 240 and 430 nm after post-chromatographic derivatization with vanillin-sulphuric acid reagent. A precise and accurate quantification can be performed in the linear working concentration range of 1000-5000 ng/spot with good correlation (r 2 = 0.994). The method was validated for peak purities, precision, robustness, limit of detection (LOD) and quantitation (LOQ), etc., as per ICH guidelines. Specificity of quantitation was confirmed using retention factor (R f ), UV-vis spectral correlation and ESI-MS spectra of marker compound (IG) in sample track.
Journal of Separation Science, 2007
A sensitive, selective, precise, and robust high-performance thin-layer chromatography method was... more A sensitive, selective, precise, and robust high-performance thin-layer chromatography method was developed and validated for analysis of two new recently isolated sterols, 4α-methyl-24β-ethyl-5α-cholesta-14,25-dien-3β-ol (1) and 24β-ethylcholesta-5,9(11),22E-trien-3β-ol (2), and a triterpene, betulinic acid (3), in Clerodendrum inerme extract. The method employed HPTLC plates precoated with silica gel 60F254 as the stationary phase. To achieve good separation, an optimised mobile phase consisting of toluene-acetone (94:06, v/v) was used (Rf 0.48, 0.34, and 0.22 for compounds 1, 2, and 3, respectively). Densitometric determination of the above compounds was carried out in reflection/absorption mode at 620 nm. Optimised chromatographic conditions provide well separated compact spots for the compounds 1, 2, and 3. The calibration curves were linear in the concentration range of 100–2500 ng/spot. The method was validated for precision, robustness, and recovery. The limits of detection and quantitation were 5, 6, and 10 μg/mL and 14, 18, and 29 μg/mL, respectively, for 1, 2, and 3. The method reported here is reproducible and convenient for quantitative analysis of these compounds in the aerial parts of C. inerme.
Phytochemical Analysis, 2002
A simple, precise and rapid high performance thin layer chromatographic method has been developed... more A simple, precise and rapid high performance thin layer chromatographic method has been developed for the simultaneous quantitative determination of five oleane derivatives, namely, arjunic acid, arjunolic acid, arjungenin, arjunetin and arjunglucoside I from stem bark extract of Terminalia arjuna. The isolation and separation of these compounds was carried out on 60F254 layers eluted with chloroform:methanol (90:10), and the analytes were visualised through colour development with vanillin in concentrated sulphuric acid:ethanol. Scanning and quantification of the spots at 640 nm showed good recoveries in the range 96.40–101.7%. Copyright © 2002 John Wiley & Sons, Ltd.
Journal of Separation Science, 2008
A sensitive, selective, and robust high-performance TLC (HPTLC) method using chiral TLC plates fo... more A sensitive, selective, and robust high-performance TLC (HPTLC) method using chiral TLC plates for qualitative and quantitative analysis of phyllanthin (A), hypophyllanthin (B), niranthin (C), and nirtetralin (D), the active lignans of Phyllanthus species, was developed and validated. The effectiveness and role of various stationary phases viz TLC silica gel 60F254, HPTLC silica gel 60F254, and chiral TLC plates in the quantitation were evaluated. A precoated chiral TLC plate was found suitable for the simultaneous analysis of four pharmacologically active lignans. For achieving good separation, the optimized mobile phase of n-hexane/acetone/1,4-dioxane (9:1:0.5 by volume) was used (Rf = 0.30, 0.36, 0.41, and 0.48 for compounds A, B, C, and D, respectively). A densitometric determination of the above compounds was carried out in reflection/absorption mode at 620 nm. Optimized chromatographic conditions provide well-separated compact bands for the tested lignans. The calibration curves were found linear in the concentration range of 100–500 ng/band. Recoveries of A–D were 99.98, 100.51, 99.22, and 98.74%, respectively. The method was validated according to ICH guidelines. The method reported here is reproducible and applied for the quantitative analysis of the above lignans in the leaves of four Phyllanthus species, i. e., P. amarus, P. maderaspatensis, P. urinaria, and P. virgatus.
Journal of Asian Natural Products Research, 2009
Two new lignans, 3-(3,4-dimethoxy-benzyl)-4-(7-methoxy-benzo[1,3]dioxol-5-yl-methyl)-dihydrofuran... more Two new lignans, 3-(3,4-dimethoxy-benzyl)-4-(7-methoxy-benzo[1,3]dioxol-5-yl-methyl)-dihydrofuran-2-one (1) and 4-(3,4-dimethoxy-phenyl)-1-(7-methoxy-benzo[1,3]dioxol-5-yl)-2,3-bis-methoxymethyl-butan-1-ol (2), were isolated from the leaves of Phyllanthus amarus and their structures were established by spectral analysis. Additionally, eight known lignans were also isolated and characterized.
Phytochemistry, 1996
A random collection of 700 plants of a seed-raised population of Artemisia annua cv. Asha were sc... more A random collection of 700 plants of a seed-raised population of Artemisia annua cv. Asha were screened for morphology and artemisinin and essential oil contents. Four morphologically distinct plant types were detected: short and early flowering, tall and early flowering, tall and late flowering, and dwarf and very late flowering. The artemisinin and essential oil were largely present in the inflorescence of all the types of plants. The artemisinin and the essential oil content in the dried herb (inflorescence + leaves) of these plant types ranged from 0.001 to 0.11% and 0.14 to 0.60%, respectively; the late flowering plants were generally richer in both artemisinin and the essential oil. Eleven individual adult plants were selected on the basis of their high artemisinin yield and in vitro regeneration response to a micropropagation procedure using young inflorescence segments as explants. The micro-cloned progenies of the selected plants were tested for their growth, morphology and artemisinin yield and homology in respect to these characters with the respective parent selections. The parent-micropropagated progeny characteristics were observed to be largely congruent. The artemisinin profiles of the micropropagated progenies at vegetative, preflowering and full bloom stages indicated that while highest artemisinin accumulation occurred at full bloom stage, the artemisinin content at preflowering stage was positively correlated with that at full bloom stage. Among the material cloned in vitro and tested in the field, clone numbers 166 and 187 yield 3.2-and 2.5-fold more artemisinin per plant as compared to the parent cultivar Asha, the former due to high herb yield and latter due to high artemisinin content per se.
Journal of Liquid Chromatography & Related Technologies, 2012
A simple isocratic HPLC method has been developed for the simultaneous quantitation of three anti... more A simple isocratic HPLC method has been developed for the simultaneous quantitation of three antipsychotic indole alkaloid (IA), α-yohimbine (1), isoreserpiline (2), and 10-methoxy tetrahydroalstonine (3) in Rauwolfia tetraphylla leaf. Samples were analyzed by reverse-phase chromatography on a Waters spherisorb ODS2 column using isocratic elution with acetonitrile containing 0.1% TEA and water containing 0.1% TFA (35:65, v/v) at a flow rate of 1 mL/min, a column temperature of 30°C, and UV detection at 210 nm. The method was validated and applied for quantification of individual alkaloids in various leaf extracts of R. tetraphylla. The method allowed simultaneous determination of alkaloids, 1, 2, and 3 in the plant. The limits of detection and quantification were 1.30, 1.16, 1.01, and 4.35, 3.88, and 3.39 µg/mL (20 µL injection) for compounds 1, 2, and 3, respectively. The method is simple, accurate, and precise which may be recommended for the routine quality control analysis of R. tetraphylla leaf extract containing these three IA as antipsychotic principles in the herb.
Phytochemistry, 2005
Three neo-clerodane diterpenoids, inermes A, B and 14,15-dihydro-15b-methoxy-3-epicaryoptin, have... more Three neo-clerodane diterpenoids, inermes A, B and 14,15-dihydro-15b-methoxy-3-epicaryoptin, have been isolated from the hexane extract of the leaves of Clerodendrum inerme in addition to an epimeric mixture of 14,15-dihydro-15-hydroxy-3-epicaryoptin. Structures of these compounds have been elucidated on the basis of spectral studies.
Phytochemistry, 1990
ABSTRACT
Journal of Pharmaceutical and Biomedical Analysis, 2002
A rapid, sensitive and reproducible reversed phase high performance liquid chromatographic method... more A rapid, sensitive and reproducible reversed phase high performance liquid chromatographic method with photo diode array detection is described for the simultaneous quantification of major oleane derivatives: arjunic acid (4), arjunolic acid (3), arjungenin (2) and arjunetin (1) in Terminalia arjuna extract. The method involves the use of a Waters Spherisorb S10 ODS2 column (250 × 4.6 mm, I.D., 10 mm) and binary gradient mobile phase profile. The various other aspects of analysis viz. Extraction efficiency, peak purity and similarity were validated using a photo diode array detector.
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Papers by Ram Kishor Verma