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Papers by Dattatraya Naik

Research paper thumbnail of Geotrichum candidum Assisted Synthesis of Sitophilate, Male Aggregation Pheromone of Granary Weevil

Synthetic Communications, 1998

The syntheses of optically inactive Sitophilate and the optically active isomers (2S, 3S) and (2S... more The syntheses of optically inactive Sitophilate and the optically active isomers (2S, 3S) and (2S, 3R) were completed by a simple route using easily avilable starting compounds.

Research paper thumbnail of Chemical Examination and Evaluation of Antioxidant and Antimicrobial Activities of Essential Oil from Gymnema sylvestre R. Br. Leaves

Journal of Essential Oil Research, 2011

The present study reports chemical examination and in vitro antioxidant and antimicrobial activit... more The present study reports chemical examination and in vitro antioxidant and antimicrobial activities of essential oil isolated from leaves of a well known antidiabetic plant, Gymnema sylvestre R. Br. Essential oil was isolated from leaves by hydrodistillation using a Clevenger apparatus. The essential oil was found to contain 40 volatile compounds by GC/MS analysis. Hitherto unknown major components of essential oil identified by GC/MS analysis were found to be palmitic acid (17.8%), hydroquinone (13.9%), phytol (6.9%), pentadecanoic acid (6.8%), 4-vinyl guaiacol (4.5%), and eugenol (4.0%). Essential oil exhibited strong 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (IC50 28 μg/mL). Dose dependent antioxidant activity was shown by essential oil in β-carotene bleaching and 2,2-azinobis-(3-ethyl benzothiazoline-6-sulphonic acid) diammonium salt (ABTS) radical scavenging assays. The total phenolic content of essential oil was found to be 34 mg GAE/g fresh leaves. The essential oil inhibited the growth of Pseudomonas aeruginosa, Pseudomonas asplenii, Bacillus subtilis, Proteus mirabilis, Escherichia coli and fungus Candida albicans with minimal inhibitory concentration (MIC) varying between 22 mg/mL and 28 mg/mL

Research paper thumbnail of Pheromone-like’ compounds in the cuticle of aquatic Chironomus larva

Chemistry and Ecology, 2006

Chironomid midges are the most commonly found dipteran insects in all types of aquatic ecosystems... more Chironomid midges are the most commonly found dipteran insects in all types of aquatic ecosystems. Cuticular extract was bio-assayed, and it exhibited enhanced attraction to the larvae. Therefore, it was subsequently analysed by gas chromatography-mass spectrometry. Two compounds were identified as farnesol and farnesene. Bioassay of farnesol indicated its attractive properties. The components present in the cuticular extract can, therefore, be considered as pheromone-like compounds.

Research paper thumbnail of Antioxidant properties of Indian propolis

Journal of Apiproduct and Apimedical Science, 2009

Antioxidant properties of total ethanolic extract of Indian propolis were investigated in this st... more Antioxidant properties of total ethanolic extract of Indian propolis were investigated in this study, and the antioxidant activity of hexane soluble portion, ethyl acetate soluble portion and ethanol soluble portion of the crude propolis were also determind. Although the alcoholic extract (TEEP) showed moderate antioxidant activity, it was found that ethyl acetate soluble fraction of propolis (EAFP) exhibited superior antioxidant activity to the activity of trolox at the same concentration. Also it showed the maximum DPPH scavenging activity (81%) and NO . radical scavenging activity (60%) as compared to the other formulations which were higher. The ethyl acetate soluble fraction was found to exhibit strongest trolox equivalent antioxidant capacity and other free radical scavenging activities. From IC 50 values it was deduced that antioxidant compounds were located in the ethyl acetate soluble fraction. Thus Indian propolis was shown to act as a natural antioxidant; these properties may make it useful for pharmaceutical industries and as a food supplement.

Research paper thumbnail of Regulation of Reproduction in the Primitively Eusocial Wasp Ropalidia marginata : on the Trail of the Queen Pheromone

Journal of Chemical Ecology, 2010

Queens and workers are not morphologically differentiated in the primitively eusocial wasp, Ropal... more Queens and workers are not morphologically differentiated in the primitively eusocial wasp, Ropalidia marginata. Upon removal of the queen, one of the workers becomes extremely aggressive, but immediately drops her aggression if the queen is returned. If the queen is not returned, this hyper-aggressive individual, the potential queen (PQ), will develop her ovaries, lose her hyper-aggression, and become the next colony queen. Because of the non-aggressive nature of the queen, and because the PQ loses her aggression by the time she starts laying eggs, we hypothesized that regulation of worker reproduction in R. marginata is mediated by pheromones rather than by physical aggression. Based on the immediate loss of aggression by the PQ upon return of the queen, we developed a bioassay to test whether the queen’s Dufour’s gland is, at least, one of the sources of the queen pheromone. Macerates of the queen’s Dufour’s gland, but not that of the worker’s Dufour’s gland, mimic the queen in making the PQ decrease her aggression. We also correctly distinguished queens and workers of R. marginata nests by a discriminant function analysis based on the chemical composition of their respective Dufour’s glands.

Research paper thumbnail of Variability in Foliar Essential Oils among Different Morphotypes of Lantana Species Complexes, and Its Taxonomic and Ecological Significance

Chemistry & Biodiversity, 2009

The genus Lantana has many species complexes, and L. camara is one of the aggressive alien weedy ... more The genus Lantana has many species complexes, and L. camara is one of the aggressive alien weedy species complexes; species delimitation in these complexes is a nightmare for taxonomists. We examined the diversity in the chemical composition of foliar essential oils among morphotypes of Lantana species complexes inhabiting the same ecological gradient, and its taxonomic and ecological significance. The yields of essential oils varied from 0.1 to 0.79% in foliar hydrodistillates of eleven morphotypes, and a total of 39 chemical constituents were detected by GC/MS. The quantitative and qualitative variability in the composition of essential oils among morphotypes was very high, and hence they represent chemotypes. The diversity observed in the composition of essential oils appears to be of genetic origin and thus of taxonomic value. The formation of distinct clusters and sub-clusters at high distance cluster combine values also substantiates that the patterns of distribution of chemical constituents among morphotypes can be used in delimiting species and infraspecific taxa within the species complexes. The presence of β-caryophyllene and other such compounds, which are known to prevent herbivory, in morphotypes of Lantana species complexes suggest that these compounds may provide selective advantage to Lantana over native species in the invasion of new and disturbed habitats.

Research paper thumbnail of Variability in Foliar Essential Oils among Different Morphotypes of Lantana Species Complexes, and Its Taxonomic and Ecological Significance

Chemistry & Biodiversity, 2009

The genus Lantana has many species complexes, and L. camara is one of the aggressive alien weedy ... more The genus Lantana has many species complexes, and L. camara is one of the aggressive alien weedy species complexes; species delimitation in these complexes is a nightmare for taxonomists. We examined the diversity in the chemical composition of foliar essential oils among morphotypes of Lantana species complexes inhabiting the same ecological gradient, and its taxonomic and ecological significance. The yields of essential oils varied from 0.1 to 0.79% in foliar hydrodistillates of eleven morphotypes, and a total of 39 chemical constituents were detected by GC/MS. The quantitative and qualitative variability in the composition of essential oils among morphotypes was very high, and hence they represent chemotypes. The diversity observed in the composition of essential oils appears to be of genetic origin and thus of taxonomic value. The formation of distinct clusters and sub-clusters at high distance cluster combine values also substantiates that the patterns of distribution of chemical constituents among morphotypes can be used in delimiting species and infraspecific taxa within the species complexes. The presence of β-caryophyllene and other such compounds, which are known to prevent herbivory, in morphotypes of Lantana species complexes suggest that these compounds may provide selective advantage to Lantana over native species in the invasion of new and disturbed habitats.

Research paper thumbnail of Geotrichum candidum Assisted Synthesis of Sitophilate, Male Aggregation Pheromone of Granary Weevil

Synthetic Communications, 1998

The syntheses of optically inactive Sitophilate and the optically active isomers (2S, 3S) and (2S... more The syntheses of optically inactive Sitophilate and the optically active isomers (2S, 3S) and (2S, 3R) were completed by a simple route using easily avilable starting compounds.

Research paper thumbnail of Chemical Examination and Evaluation of Antioxidant and Antimicrobial Activities of Essential Oil from Gymnema sylvestre R. Br. Leaves

Journal of Essential Oil Research, 2011

The present study reports chemical examination and in vitro antioxidant and antimicrobial activit... more The present study reports chemical examination and in vitro antioxidant and antimicrobial activities of essential oil isolated from leaves of a well known antidiabetic plant, Gymnema sylvestre R. Br. Essential oil was isolated from leaves by hydrodistillation using a Clevenger apparatus. The essential oil was found to contain 40 volatile compounds by GC/MS analysis. Hitherto unknown major components of essential oil identified by GC/MS analysis were found to be palmitic acid (17.8%), hydroquinone (13.9%), phytol (6.9%), pentadecanoic acid (6.8%), 4-vinyl guaiacol (4.5%), and eugenol (4.0%). Essential oil exhibited strong 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (IC50 28 μg/mL). Dose dependent antioxidant activity was shown by essential oil in β-carotene bleaching and 2,2-azinobis-(3-ethyl benzothiazoline-6-sulphonic acid) diammonium salt (ABTS) radical scavenging assays. The total phenolic content of essential oil was found to be 34 mg GAE/g fresh leaves. The essential oil inhibited the growth of Pseudomonas aeruginosa, Pseudomonas asplenii, Bacillus subtilis, Proteus mirabilis, Escherichia coli and fungus Candida albicans with minimal inhibitory concentration (MIC) varying between 22 mg/mL and 28 mg/mL

Research paper thumbnail of Pheromone-like’ compounds in the cuticle of aquatic Chironomus larva

Chemistry and Ecology, 2006

Chironomid midges are the most commonly found dipteran insects in all types of aquatic ecosystems... more Chironomid midges are the most commonly found dipteran insects in all types of aquatic ecosystems. Cuticular extract was bio-assayed, and it exhibited enhanced attraction to the larvae. Therefore, it was subsequently analysed by gas chromatography-mass spectrometry. Two compounds were identified as farnesol and farnesene. Bioassay of farnesol indicated its attractive properties. The components present in the cuticular extract can, therefore, be considered as pheromone-like compounds.

Research paper thumbnail of Antioxidant properties of Indian propolis

Journal of Apiproduct and Apimedical Science, 2009

Antioxidant properties of total ethanolic extract of Indian propolis were investigated in this st... more Antioxidant properties of total ethanolic extract of Indian propolis were investigated in this study, and the antioxidant activity of hexane soluble portion, ethyl acetate soluble portion and ethanol soluble portion of the crude propolis were also determind. Although the alcoholic extract (TEEP) showed moderate antioxidant activity, it was found that ethyl acetate soluble fraction of propolis (EAFP) exhibited superior antioxidant activity to the activity of trolox at the same concentration. Also it showed the maximum DPPH scavenging activity (81%) and NO . radical scavenging activity (60%) as compared to the other formulations which were higher. The ethyl acetate soluble fraction was found to exhibit strongest trolox equivalent antioxidant capacity and other free radical scavenging activities. From IC 50 values it was deduced that antioxidant compounds were located in the ethyl acetate soluble fraction. Thus Indian propolis was shown to act as a natural antioxidant; these properties may make it useful for pharmaceutical industries and as a food supplement.

Research paper thumbnail of Regulation of Reproduction in the Primitively Eusocial Wasp Ropalidia marginata : on the Trail of the Queen Pheromone

Journal of Chemical Ecology, 2010

Queens and workers are not morphologically differentiated in the primitively eusocial wasp, Ropal... more Queens and workers are not morphologically differentiated in the primitively eusocial wasp, Ropalidia marginata. Upon removal of the queen, one of the workers becomes extremely aggressive, but immediately drops her aggression if the queen is returned. If the queen is not returned, this hyper-aggressive individual, the potential queen (PQ), will develop her ovaries, lose her hyper-aggression, and become the next colony queen. Because of the non-aggressive nature of the queen, and because the PQ loses her aggression by the time she starts laying eggs, we hypothesized that regulation of worker reproduction in R. marginata is mediated by pheromones rather than by physical aggression. Based on the immediate loss of aggression by the PQ upon return of the queen, we developed a bioassay to test whether the queen’s Dufour’s gland is, at least, one of the sources of the queen pheromone. Macerates of the queen’s Dufour’s gland, but not that of the worker’s Dufour’s gland, mimic the queen in making the PQ decrease her aggression. We also correctly distinguished queens and workers of R. marginata nests by a discriminant function analysis based on the chemical composition of their respective Dufour’s glands.

Research paper thumbnail of Variability in Foliar Essential Oils among Different Morphotypes of Lantana Species Complexes, and Its Taxonomic and Ecological Significance

Chemistry & Biodiversity, 2009

The genus Lantana has many species complexes, and L. camara is one of the aggressive alien weedy ... more The genus Lantana has many species complexes, and L. camara is one of the aggressive alien weedy species complexes; species delimitation in these complexes is a nightmare for taxonomists. We examined the diversity in the chemical composition of foliar essential oils among morphotypes of Lantana species complexes inhabiting the same ecological gradient, and its taxonomic and ecological significance. The yields of essential oils varied from 0.1 to 0.79% in foliar hydrodistillates of eleven morphotypes, and a total of 39 chemical constituents were detected by GC/MS. The quantitative and qualitative variability in the composition of essential oils among morphotypes was very high, and hence they represent chemotypes. The diversity observed in the composition of essential oils appears to be of genetic origin and thus of taxonomic value. The formation of distinct clusters and sub-clusters at high distance cluster combine values also substantiates that the patterns of distribution of chemical constituents among morphotypes can be used in delimiting species and infraspecific taxa within the species complexes. The presence of β-caryophyllene and other such compounds, which are known to prevent herbivory, in morphotypes of Lantana species complexes suggest that these compounds may provide selective advantage to Lantana over native species in the invasion of new and disturbed habitats.

Research paper thumbnail of Variability in Foliar Essential Oils among Different Morphotypes of Lantana Species Complexes, and Its Taxonomic and Ecological Significance

Chemistry & Biodiversity, 2009

The genus Lantana has many species complexes, and L. camara is one of the aggressive alien weedy ... more The genus Lantana has many species complexes, and L. camara is one of the aggressive alien weedy species complexes; species delimitation in these complexes is a nightmare for taxonomists. We examined the diversity in the chemical composition of foliar essential oils among morphotypes of Lantana species complexes inhabiting the same ecological gradient, and its taxonomic and ecological significance. The yields of essential oils varied from 0.1 to 0.79% in foliar hydrodistillates of eleven morphotypes, and a total of 39 chemical constituents were detected by GC/MS. The quantitative and qualitative variability in the composition of essential oils among morphotypes was very high, and hence they represent chemotypes. The diversity observed in the composition of essential oils appears to be of genetic origin and thus of taxonomic value. The formation of distinct clusters and sub-clusters at high distance cluster combine values also substantiates that the patterns of distribution of chemical constituents among morphotypes can be used in delimiting species and infraspecific taxa within the species complexes. The presence of β-caryophyllene and other such compounds, which are known to prevent herbivory, in morphotypes of Lantana species complexes suggest that these compounds may provide selective advantage to Lantana over native species in the invasion of new and disturbed habitats.