Caffeine content of tea extracts and formulations may conveniently be assayed by a number of titrimetric, spectrophotometric, gravimetric and chromatographic methods. HPLC is the method of choice as it is subject to fewer interferences than other methods. A. Method I (Spectrophotometric assay) The method could be modified by extracting the tea infusion with dichloromethane. The…
Chemically it is 1, 3, 7-trimethyl xanthine and has the molecular formula C8H10N4O2. Caffeine has a bitter taste, is odourless and occurs as a white powder or as white needles. In its anhydrous form, caffeine contains one molecule of water of hydration; caffeine in solution is neutral in pH. It has melting range of 235–238°C…
Source Caffeine is a purine alkaloid co-occuring with minor isomeric dimethyl xanthines theobromine and theophylline. Its major sources are tea, coffee, cocoa and cola, which owe their stimulant properties to these water-soluble alkaloids. This alkaloid is found in the leaves, seeds and fruits of 63 different species of plants worldwide. Caffeine was first isolated in…
Calcium sennosides may be estimated by a number of spectrophotometric, spectrofluorimetric and chromatographic (high performance liquid chromatography, HPLC; high performance thin layer chromatography, HPTLC) methods. Calcium sennosides are extracted into boiling water, which are oxidized with ferric chloride treatment. Subsequent acid hydrolysis releases anthraquinones from glycosides that are extracted into ether. Residue of anthraquinone from…
Ever since the isolation of sennosides A and B from senna, the presence of several other constituents has been demonstrated. The purgative action of the leaf drug is attributed to the synergistic effect of several active principals chief among which are sennosides. The total leaf sennosides constituting largely of sennosides A and B are isolated…
Source Calcium sennosides are calcium salts of sennosides A and B obtained from the leaves and pods of Cassia angustifolia and Cassia acutifolia. Known in commerce as Indian and Alexandrian Senna these plants have been used as natural, safe, time-tested laxatives in traditional as well as modern systems of medicine. In India, senna is extensively cultivated in Tamil…
Rutin can be estimated colorimetrically by detection of the red colour it forms upon reduction with magnesium amalgam and hydrochloric acid. This is a useful method for the estimation of rutin content in both plant extracts and in pharmaceutical dosage forms. It may be more simply assayed spectrophotometrically by measuring its absorption in ethanol at…
Chemical tests for identification of rutin are based on the properties of phenolic hydroxyl groups of rutinose and of the benzene nucleus. It may be chromatographically identified on a paper chromatogram developed descendingly (25% isopropyl alcohol) as a brown–orange band. Rutin is even conveniently identified by UV, Nuclear Magnetic Resonance (NMR), Infrared (IR) and mass…
Rutin is a rhamnoglycoside of flavonol quercetin. Chemically it is quercetin-3-rutinoside or 3-[[6-O-(6-deoxy-alpha-L-mannopyranosyl)-beta-D-glucopyranosyl]oxy]-2-(3,4-dihydroxyphenyl)-5,7-dihydroxy-4H-1-benzopyran-4-one. It occurs as a yellow crystalline powder of melting point 191°C and has a molecular formula of C27H30O16. It is highly soluble in a number of organic solvents like methanol, ethanol, pyridine etc. It is poorly soluble in cold water (12.5 g/100ml) but…