Leaves and fruits of Phyllanthus emblica L. have been used for the anti-inflammatory and antipyretic treatment of rural populations in its growing areas in subtropical and tropical parts of China, India, Indonesia, and the Malay Peninsula. In the present study, leaves of Ph. emblica were extracted with ten different solvents (n-hexane, diethyl ether, methanol, tetrahydrofuran, acetic acid, dichloromethane, 1,4-dioxane, toluene, chloroform, and water). The inhibitory activity of the extracts against human polymorphonuclear leukocyte (PMN) and platelet functions was studied. Methanol, tetrahydrofuran, and 1,4-dioxane extracts (50 micrograms/ml) inhibited leukotriene B4-induced migration of human PMNs by 90% and N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP)-induced degranulation by 25-35%. The inhibitory activity on receptor-mediated migration and degranulation of human PMNs was associated with a high proportion of polar compounds in the extracts as assessed by normal phase thin layer chromatography. Diethyl ether extract (50 micrograms/ml) inhibited calcium ionophore A23187-induced leukotriene B4 release from human PMNs by 40%, thromboxane B2 production in platelets during blood clotting by 40% and adrenaline-induced platelet aggregation by 36%. Ellagic acid, gallic acid and rutin, all compounds isolated earlier from Ph. emblica, could not explain these inhibitory activities on PMNs or platelets by Ph. emblica extracts. These results show that the leaves of Ph. emblica have inhibitory activity on PMNs and platelets, which confirm the anti-inflammatory and antipyretic properties of this plant as suggested by its use in traditional medicine. The data suggest that the plant leaves contain as yet unidentified polar compound(s) with potent inhibitory activity on PMNs and chemically different apolar molecule(s) which inhibit both prostanoid and leukotriene synthesis.
A method was developed to measure the radicalscavenging activity of compounds separated by reversed-phase TLC (RP-TLC) using phenolic acids as model analytes. TLC separation was followed by dipping the plate in a 0.04% (wt/vol) solution of 1,1-diphenyl-2-picrylhydrazyl (DPPH) in methanol. The compounds possessing radical-scavenging activity were detected as bright yellow bands against a purple background. A video documentation system based on a CCD video camera was used for the detection and quantification of the activity. The developed RP-TLC-DPPH method was compared to the widely used spectrophotometric DPPH assay. The results obtained by the two methods correlated well, apart from syringic acid, ascorbic acid, and n-propyl gallate, which proved to be outliers in the regression analyses. The correlation coefficient, after excluding outliers, was r 2 = 0.923. The RP-TLC-DPPH method was applied for the measurement of free radical-scavenging activity of rapeseed meal fractions. A total of 10 separated zones with free radical-scavenging activity were detected, with R f values ranging from 0.04 to 0.85. The results show that the method can be used for the effective fractionation and analysis of potential antioxidative compounds in natural extracts.Paper no. J10222 in JAOCS 80, 9-14 (January 2003).KEY WORDS: 1,1-Diphenyl-2-picrylhydrazyl, free radical scavenging activity, phenolic compounds, reversed-phase thinlayer chromatography.The oxidation of lipids is the main mechanism responsible for the deterioration of food (1). The oxidation process can be prevented effectively by using free radical-scavenging antioxidants such as BHA, BHT, and propyl gallate. Furthermore, berries, fruits, and vegetables naturally contain many antioxidative compounds, for example, simple phenolics, flavonoids, and tannins. In addition to the conjugated diene method, which measures the rate of hydroperoxide formation and decomposition in different lipid systems and emulsions (2,3), radical-scavenging assays such as measurement of hydroxyl radical-scavenging activity, superoxide anion radical-scavenging activity, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity (4) have also been used.DPPH is a stable, water-soluble free radical with an absorption maximum at 517 nm (5). This strong absorption is due to the unpaired electron of the DPPH radical (4). When this radical compound accepts an electron or a hydrogen radical from a radical scavenger, the absorption vanishes and the resulting decolorization is stoichiometric with respect to the number of electrons taken up.Many variations of the spectrophotometric DPPH method, first developed by Blois (4), are currently used, and this method has attained the status of a routine procedure in the screening of antioxidants (6-10). These methods measure the total DPPH radical-scavenging activity of the extracts or fractions of interest but lack the ability to isolate the activity caused by only one or a few components of the mixture.TLC combined with DPPH radical detection of antioxida...
The coumarin composition of Peucedanum palustre (L.) Moench populations growing in Finland was investigated. A total of 132 flowering P. palustre specimens from 43 locations in southern and central Finland were collected, divided into root, stem, leaf, and umbel samples, and analyzed by HPLC. HPLC coupled to high-resolution mass spectrometry was used to aid the identification of coumarins. A total of 13 coumarin-structured compounds were quantitatively analyzed from the samples. The coumarin profile of root samples was found to differ from the aerial plant parts. The main coumarins in roots were oxypeucedanin and columbianadin. In aerial parts, peulustrin isomers were the most abundant coumarin components. Umbels and leaves also contained a considerable amount of umbelliprenin, which was only found in traces in roots. Based on hierarchical cluster analysis of the coumarin profiles, some populations shared common characteristics. The most distinct property connecting certain populations was their high peulustrin content. Another notable common property between some populations was the high umbelliprenin content in aerial plant parts. Some populations were clustered together due to their low overall coumarin content.
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