Application of fluorescence spectroscopy coupled with PLSR for the estimation of quercetin in four medicinal plants (original) (raw)
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The HPLC system coupled on-line with colorimetric detection of antioxidant activity was developed in order to separate antioxidants especially the flavonoids, rutin and quercetin, and to determine their activities in a single step. In the system developed, the eluate from the HPLC column was split into two flows at the ratio of 8:2. The major part flowed to the UV-detector set at 220 nm, while the minor part was mixed with a free radical, 2,2-diphenyl-1-picrylhydrazyl, to perform a color reaction with the eluted antioxidants. This reaction occurred in a knitted-shape reactor (70 cm 0.8 mm I.D. PTFE). The peaks indicating antioxidant activity were monitored from the decrease of absorbance at 515 nm. The results showed that the on-line HPLC coupled with antioxidant activity detection developed could separated the flavonoids, rutin and quercetin in plant extracts such as Sophora japonica and Morus alba and simultaneously determine their antioxidant activity. The detection limits for th...
Journal of Liquid Chromatography & Related Technologies, 2001
of Maced on ia , Institute of Pharmac ogno sy, Faculty of Pharmacy, Vod nj an ska 17, 1000 Skopje, Repub lic of Maced on ia ABSTRACT A new and ra pid procedure for sc reening of flavonols (rnyrice tin, querce tin and kaernpferol) and fo r determ ination o f quer cetin by RP-I-IP LC w ith UV-di ode array detecti on in 16 medi c inal plants is presen ted . Scree ning of the ex trac ts sh owed that q uerce tin is the most abundan t flavon ol , es pecia lly in Hyp erici herba , Uvae ursifolium and Pruni sp inosaejlos . Kaemp ferol was the most ab unda nt in Rvbi niae pse udoaca ciae flos an d Pruni spin osaeflos, whe reas myricetin was identified onl y in Betulae folium.
International Journal of Pharmaceutical Sciences Review and Research, 2021
Flavonoids are secondary plant metabolites normally found as pigmented compounds in plants. Quercetin and rutin are two important and commonly found flavonoids in nature and exhibit wide pharmacological effects such as antioxidant, anticarcinogenic, antiviral, anti-inflammatory, antidiabetic, and hepatoprotective activities as well as antimicrobial activity. In this study, quercetin and rutin content is being quantified in the plant extracts of Centella asiatica and Houttuynia cordata and considerable amounts of these two flavonoids were depicted. A single beam UV – Spectrophotometer was used to measure the absorbance of the standard as well as test solutions. Calibration curves were constructed for standard quercetin and rutin in such a way that x-axis denotes concentration and the y-axis denotes the absorbance. The calibration curves showed linearity at concentrations 5-25 ?g /ml of quercetin and rutin respectively with a good correlation coefficient (r) of 0.99 for both the curve...
Measurement, 2018
Quercetin is a well-known flavonoid that has been listed as ingredient in many supplements, beverages and foods for a long time. The use of quercetin has been widely associated with a great number of health benefits such as antioxidant, anti-inflammatory, antiviral and anticancer as well as to ease some cardiovascular diseases such as heart disease, hypertension, and high blood cholesterol. In this study, a new sensitive fluorescence emission spectroscopy coupled with partial least square regression (PLSR) was developed as a new method for the estimation of quercetin in different fractions of Euphorbia masirahensis and the obtained results were cross validated by UV-visible spectroscopy. emission spectroscopic analysis, followed by PLS regression. The results indicated that n-butanol fraction containing the higher quercetin contents i.e. (5.83 ± 0.09 %) followed by ethyl acetate fraction i.e. (4.25 ± 0.06%). The newly proposed fluoresence method was also parellel cross validated with UV-visible spectroscopy. The results from both methods were found to be very consistent but the fluorescence-PLSR method was found to be of higher accuracy due to its high sensitivity having slope value is 0.997 with small value of error i.e. 0.355 % of RMSE. This newly proposed emission spectroscopic method coupled with PLSR is sensitive, reproducible simple, ecofriendly and non-destructive.
A Simple HPLC Method for Quantitation of Quercetin in Herbal Extracts
Journal of AOAC INTERNATIONAL
A reversed-phase HPLC method with UV detection was developed for the determination of quercetin. The method produced linear response over a wide concentration range, with an average accuracy of 95% and average intra- and interday variation of 0.75 and 0.3, respectively. The exactness of the method was proven by determining the recovery rates from 50 to 150% of standard concentration, which were found within the acceptable range of 95 to 105%. The method was used for quantitation of quercetin in the extracts of Psidium guajava, Vitis vinifera, and extracts rich in quercetin and other flavonols in the flavonoid family.
Quercetin content in some food and herbal samples
Food Chemistry, 2007
Quercetin is a typical flavonoid ubiquitously present in vegetables and fruits, and its antioxidant effect is implied to be helpful for human health. The efficiency of extraction process and acidic hydrolysis parameters for HPLC analysis of quercetin present in glycosides and aglycone forms was investigated. Hydrolysis for 5 min in the presence of 2.8 M HCl as well as for 10 min with 1.1 M HCl efficiently released quercetin from rutin. The method developed in this study was applied for quantitative determination of quercetin in some food (onion, apple) and herbal (Hypericum perforatum and Sambucus nigra) products.
2021
Herbal medicines and their preparations have been mostly used since from thousands of years in all developing and developed countries in the primary health care of society and community. Flavonoids are the class of polyphenolic compounds, which are mainly distributed throughout the plant kingdom. Quercetin is a flavonoid which shows major pharmacological activities and effectively used for the management and treatment of various diseases and disorders. Many herbal medicines and their formulations containing Quercetin are available in market and hence quality control of Quercetin in is very important and essential in manufacturing industries We have reviewed various scientific research published on quality control analysis and standardization of Quercetin in its isolated form, extract or any other herbal or polyherbal preparation. We have mainly focused on the spectroscopic and chromatographic methods for qualitative and quantitative analysis of Quercetin and they were comprehensivel...
Determination of quercetin in some natural products using reversed FIA-CL method
Der Pharma Chemica, 2011
This paper reports a new and simple flow injection analysis with chemiluminescence (CL) system for determination of quercetin through the reverse flow injection technique. The method was based on the inhibition of the CL of H 2O 2-luminal-permanganate with quercetin. The reverse flow was used to avoid continuous monitors of CL which leads to unstable baseline. Various parameters associated with this flow system were studied and essential optimizations were carried out. Two calibration graphs were constructed for determination of quercetin in the range (6.0-12 μg/ml) with correlation coefficient (0.9994) for low concentration level and (20-190 μg/ml) with correlation coefficient (0.9962) for high concentration and a sampling frequency 80 samples/h. Possible interferences were studied and the results showed that the interferences caused less than 5% error. The method was applied successfully for the determination of quercetin in various natural products.
Physical Chemistry Chemical Physics, 2014
In this work we report the study of the chemical modifications undergone by flavonoids, especially by quercetin (QUC), under alkaline conditions by UV-visible absorption, Raman and surface-enhanced Raman scattering (SERS) spectroscopy, the study was performed in aqueous solution and also on Ag nanoparticles (AgNPs). Several processes are involved in the effect of alkaline pH both in solution and on AgNPs: autoxidation affecting mainly the C-ring of the molecule and giving rise to the molecular fragmentation leading to simpler molecular products, and/or the dimerization and further polymerization leading to species with a higher molecular weight. In addition, there exists a clear structure-instability correlation concerning mainly particular groups in the molecule: the C3-OH group in the C-ring, the catechol moiety in the B-ring and the C2QC3 bond also existing in the C-ring. QUC possesses all these groups and exhibits high instability in alkaline solution. The SERS spectra registered at different pH revealed a change in the dimerization protocol of QUC going from the A-and C-rings-likecondensation to B-ring-like-condensation. Increasing the knowledge of the chemical properties of these compounds and determining the structure-activity relationship under specific environmental factors allow us to improve their beneficial properties for health as well as the preservation of Cultural Heritage objects, for example, by preventing their degradation. 91 5 64 55 57; Tel: +34 91 5 61 68 00 † Electronic supplementary information (ESI) available. See
Analysis of Total Flavonoids in Herbal Drugs Expressed as Quercetin by Reversed Phase-UHPLC Method
Bulletin of Faculty of Science, Zagazig University
A rapid and accurate reversed phase-UHPLC method is developed for determination of gallic acid, quercetin and kaempferol in herbal drugs found in herbal product purchased from local market. A reversed phase chromatographic analysis is carried out under isocratic conditions using column Phenomenex, Prodigy, ODS3, 5.0 μm, 100 A, 250 × 4.6 mm (USA). The mobile phase is methanol and 0.5 % phosphoric acid (50:50 v/v). The flow rate is 1.3 mL min-1. The injection volume is 20 µL. The detection wavelength (λ max) is 370 nm using a PDA (photodiode array detector). Linearity of the method is established over the concentration ranges of 240-960 µg mL-1 for quercetin with a retention time about 7.8 minutes. Correlation coefficient is greater than 0.99. The recovery level of quercetin is 99.94 %. The described method is quite suitable for routine analysis of herbal drugs by reversed phase-UHPLC Method. The proposed method is used for routine analysis to estimate the selected polyphenols under study in its pure form as well as in some herbal drugs forms.