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Antifungal Activity of Mucuna pruriens Seed Extractives and L-dopa

Wed, 01 Jun 2011 00:00:00 GMT

Title: Antifungal Activity of Mucuna pruriens Seed Extractives and L-dopa Authors: Eugene Sebastian, J Nidiry; Girija, Ganeshan; A N, Lokesha Abstract: The seeds of Mucuna pruriens (L.) D.C. (Leguminosae) were extracted first with hexane, then with ethyl acetate, and finally with methanol. The solvents were removed to get the respective extractives. These were assessed for the mycelial growth inhibition of three phytopathogenic fungi—Colletotrichum gloeosporioides, Colletotrichum capsici, and Fusarium solani—by the poisoned-food technique. Methanol extractive showed highest activity against all the three test organisms. L-dopa [3-(3,4-Dihydroxyphenyl)-L-alanine], which was qualitatively detected in the ethyl acetate and methanol extractives and quantitatively assessed in the seeds, showed antifungal activity against all the three test organisms, showing that it is one of the active principles in these extractives.

Phytochemical diversity in Ashwagandha (Withania somnifera)

Mon, 01 Nov 2010 00:00:00 GMT

Title: Phytochemical diversity in Ashwagandha (Withania somnifera) Authors: D H, Sukanya; A N, Lokesha; Gayatri, Datta; K, Himabindu Abstract: Ashwagandha (Withania somnifera Dunal) is an important commercial medicinal crop, which is considered as an alternate to Ginseng. It is a superior class herb with multiple benefits. Fruits, leaves and seeds of the plant have been used for ages in Ayurveda. The root has been used most frequently for therapeutic uses and is a constituent of over 200 formulations in Ayruvedha, Siddha and Unani medicines. The biologically active chemical constituents are withanolides with adaptogenic, aphrodisiac, diuretic, memory boosting and stress relieving properties. It is also protective towards arthritis, cartilage degradation, leprosy etc. Owing to its diverse therapeutic uses, there is renewed interest in phytochemistry of this crop. A large number of withanolides have been identified and different therapeutic activities are associated with different constituents viz., Withaferine A associated with anti-inflammatory activity and is a safe radiosensitizer/chemotherapeutic agent, Withanolide A and Withanoside IV known for treatment of neurodegenerative diseases and Withanone for anti-cancer and antiaging activities etc. The success of genetic improvement in this medicinal crop strongly depends on diversity of phytochemical content along with high potential for root yield. Though there are many reports on diversity for root yield and associated traits, systematic studies on chemical diversity are highly scarce and limited. Therefore efforts were made for systematic collection and evaluation of germplasm from diverse geographical locations in India (186) and 108 selected accessions were assessed for chemical diversity at Indian Institute of Horticultural Research, Bangalore, Karnataka. The accessions differed both quantitatively and qualitatively for withanolides estimated by HPLC method. The total withanolide content ranged from 0.066 to 0.588% on dry root basis in the accessions and as many as 13 accessions recorded more than 0.30%, which are considered as commercially viable. The analysis of withanolide profile in these accessions paved the way for identification of superior chemotypes, which recorded higher content of specific withanolides of therapeutic importance viz., Withaferine A (0.345%), Withanolide A (0.125%) & B (0.068%), Withnone (0.100%), Withanostromalide (0.048%) and Withanoside IV (0.227) & Withanoside V (0.042) and also absence of specific withanolides such as waithanostromalide, withanone, withanoside V and withanolide B, thus indicating considerable diversity in the collection for phyto-chemicals. These chemotypes with high content of specific compound are very important from pharmaceutical perspective.

Quantitative structure-fungitoxicity relationships of some monohydric alcohols

Fri, 01 Aug 2003 00:00:00 GMT

Title: Quantitative structure-fungitoxicity relationships of some monohydric alcohols Authors: Eugene Sebastian, J. Nidiry Abstract: The fungitoxicity data of some monohydric alcohols on the mycelial growth inhibition of Colletotrichum gloeosporioides were subjected to quantitative structure-activity relationship (QSAR) studies. The very large variation in the median effective concentrations ranging from >24000 mg/L [pEC(50)(mol/L)= 0.11] in the case of methanol to <100 mg/L [pEC(50)(mol/L)= 3.27] in the case of citronellol was found to depend mainly on changes in calculated partition coefficients (CLogP) of the compounds. The other three factors that affected the variation in fungitoxicity are the number of hydrogen atoms on the carbon bearing the hydroxyl group (N(H)), which determines the class of the alcohol to be primary, secondary, or tertiary, the number of double bonds (N(=)), and the branching of the alkyl moiety. Because many compounds in the set under study belonged to homologous series, there was a collinearity between CLogP values and Kier's molecular connectivity values (chi), which are usually used as branching indices. The problem of collinearity between CLogP values and branching indices was overcome by taking the relative molecular connectivity (chi(rel)), which is defined as the ratio of molecular connectivity of the alcohol under consideration to the molecular connectivity of the corresponding straight-chain primary alcohol with the same number of carbon atoms. Apart from the excellent correlations obtained in the equations, the credibility of the QSAR model could also be demonstrated by its application to published data taken from the literature.

Structure–fungitoxicity relationships of some volatile flavour constituents of the edible mushrooms Agaricus bisporus and Pleurotus florida

Mon, 01 Jan 2001 00:00:00 GMT

Title: Structure–fungitoxicity relationships of some volatile flavour constituents of the edible mushrooms Agaricus bisporus and Pleurotus florida Authors: Eugene Sebastian, J. Nidiry Abstract: The fungitoxicity of the diethyl ether extracts of two basidiomycete mushrooms, Agaricus bisporus and Pleurotus florida, and 14 flavour constituents present in these mushrooms is being reported. Median effective molar concentrations (EC50) of the compounds for the mycelial growth inhibition of Colletotrichum gloeosporioides on potato–dextrose–agar (PDA) medium were computed and compared. Among the constituents tested for fungitoxicity, 1-octanol exhibited the highest activity. Structure–activity relationship studies of the constituents revealed that high hydrophobicity of the alkyl moiety, the presence of the primary alcoholic group and the absence of branching of the alkyl group are responsible for the high activity of 1-octanol.