quercetin

A simple and reliable high performance thin layer chromatographic (HPTLC) method has been developed and validated for the study of fingerprint chromatograms of the hexane , chloroform, ethyl acetate and aqueous extracts of leaves of Hemigraphis colorata (blume) H.G. Hallier .HPTLC separation of the all extracts was performed and scanned  at ultraviolet absorbance at 254 nm. A mobile phase composed of toluene: ethyl acetate: formic acid :methanol (3:6:1.6:0.4).The chromatogram obtained and the peak profile of the components collected by scanning could  made up the fingerprint of the  various  extracts from leaves of  Hemigraphis colorata and compared with antioxidants markers of flavonoids and phenolic acids. The fingerprint chromatograms had a good stability, precision, and reproducibility. The method is suitable for differentiation of extracts from the leaves of Hemigraphis colorata, and can be used as a quality control method for this plant.

Drug-protein interactions are important since most of the administered drugs are extensively and reversibly bound to albumin and drug is transported mainly as a complex with protein.  The interactions between quercetin and Egg albumin was analyzed by fluorescence resonance energy transfer theory. According to this, the average binding distance between quercetin and egg albumin was obtained.

Arbutin and quercetin are anti-cancer agents, extracted from leaves and flowers of Origanum majorana L which can be simultaneously estimated using a rapid, specific and sensitive high – performance thin layer chromatographic technique using silica gel G60F254 as the stationary phase and butyl acetate: methanol: formic acid: toluene (8: 1.5: 5: 0.5) as mobile phase for the separation. The method was validated for linearity, precision and recovery. Linearity was established in the range 300-900 ng/spot for arbutin and 150-450 ng/spot for quercetin, respectively. The % RSD values of repeatability of application, repeatability of measurement, intra-day and inter day precision studies of arbutin and quercetin were found to be below 1 for 500 and 250 ng/spot of arbutin and quercetin, respectively. The recovery of the drugs were found to be 99.8 and 100.2%, proves that the developed method was highly accurate. Hence the proposed validated method could be applied for the simultaneous analysis of arbutin and quercetin in methanolic extract of Origanum majorana L as well as for its marketed formulation.

Euphorbia Hirta belonging to the Euphorbiaceae family contains more amounts of phenolic compounds and flavonoids which are responsible for the main pharmacological actions like anti-oxidant, anti-inflammatory, anti-dengue and anti-cancer. Considering the current importance of these ingredients, an attempt has been made for the simultaneous estimation of gallic acid, rutin and quercetin from euphorbia hirta by successive extraction involves the use of solvents in an order of increasing polarity in soxhlet extractor at 30-45 °C using 800 ml solvents for 5 hours in increasing polarity to isolate the active constituents without other interferences. Hence we proposed to develop easy, rapid, accurate, precise and reliable analytical HPTLC method for the standardization of Euphorbia hirta(L) using gallic acid, rutin and quercetin as phytochemical markers from its methanolic extract and herbal capsule formulation. The separation was performed on TLC aluminum Plates precoated with silica gel 60F254, good separation was achieved in the mobile phase of butyl acetate: 1,4-dioxane (5:5% v/v) and densitometric determination of gallic acid, rutin and quercetin was carried out at 266nm.The linear regression data showed a good linearity in the concentration range of 136-748ng/spot of gallic acid, rutin and quercetin with a good correlation coefficient of 0.9989. Limit of detection was found to be 102 ng/spot of gallic acid,17ng/spot of rutin and 68ng/spot of quercetin. The limit of quantification for the estimation of gallic acid, rutin and quercetin was found to be 136ng/spot.

  The present study investigates the beneficial role of anthocyanin extracted from two varieties of onion peel (Allium cepa L.,). And also to find out the quercetin and cyanidin present in the red onion peel and big onion peel by using HPLC. Key words; Allium cepa, red onion peel, big onion peel, anthocyanin, quercetin, cyanidin, HPLC.