The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform
Eelke Jongejans - One of the best experts on this subject based on the ideXlab platform.
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Bottlenecks and spatiotemporal variation in the sexual
2020Co-Authors: Eelke Jongejans, Merel B. Soons, Hans De KroonAbstract:19 Sexual reproduction is important for the growth of populations and the maintenance of 20 genetic diversity. Several steps are involved in the sexual reproduction pathway of plants: 21 the production of flowers, the production of seeds and the establishment of seedlings 22 from seeds. In this paper we quantify the relative importance and spatio-temporal 23 variability of these different steps for four grassland perennials: Centaurea jacea, 24 Cirsium dissectum, Hypochaeris radicata and Succisa pratensis. We compared 25 undisturbed meadows with meadows where the top soil layer had been removed as a 26 restoration measure. Data on the number of flower heads per flowering rosette, the 27 numbers of flowers and seeds per flower head, and the seedling establishment 28 probabilities per seed were collected by field observations and experiments in several 29 sites and years. Combination of these data shows that H. radicata and S. pratensis have 30 higher recruitment rates (1.9 and 3.3 seedlings per year per flowering rosette, 31 respectively) than the more clonal C. dissectum and C. jacea (0.027 and 0.23, 32 respectively). Seedling establishment is the major bottleneck for successful sexual 33 reproduction in all species. Large losses also occurred due to failing seed set in C. 34 dissectum. Comparison of the coefficients of variation per step in space and time revealed 35 that spatio-temporal variability was largest in seedling establishment, followed closely by 36 flower head production and seed set.
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Region versus site variation in the population dynamics of three short-lived perennials.
Journal of Ecology, 2010Co-Authors: Eelke Jongejans, Linda D. Jorritsma‐wienk, Ute Becker, Petr Dostál, Mikael Mildén, Hans De KroonAbstract:Summary 1. When range shifts or invasions of plant species are studied, it is important to know whether large-scale spatial variation in a species’ demography can be ignored or approximated by variation observed over smaller spatial scales. 2. Here, we studied the population dynamics of three similar (as shown by elasticity analysis) shortlived perennial plant species in multiple sites in different European countries over 2 years. We constructed a total of 40 transition matrices and analysed the spatio-temporal variation in the projected population growth rate (k) with spatially nested life table response experiments (LTRE). 3. All species (Carlina vulgaris, Tragopogon pratensis and Hypochaeris radicata )s howed considerable life-history variation among regions on top of variation among sites within regions. 4. Net variance contributions (NVC), a novel LTRE statistic, revealed that in each species, variation in one group of vital rates contributed most to variation in k among regions as well as among sites. However, that most important type of vital rates differed between species: plant growth in C. vulgaris, flower head production in T. pratensis and establishment probability of seedlings in H. radicata. The rankings of the NVCs of other vital rates varied between site and region effects, suggesting that buffering through negative vital rate correlations varies over different spatial scales, while the identity of the main contributor tok variation is more constant. 5. Temporal effects were smaller than spatial effects, but the LTREs showed strong interactions between time and space (region or site), suggesting that the effect of, e.g. climate fluctuations are not synchronized throughout the distribution of a species. 6. Synthesis. This study shows that the life histories of plant species are distinguishable even when mean elasticity values show only small differences, and that life histories vary over the distribution range of a species. Demographic differences over large spatial scales can therefore only be partly substituted by small scale spatial variation in modelling studies on the population dynamics of a species across its entire distribution.
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the interplay between shifts in biomass allocation and costs of reproduction in four grassland perennials under simulated successional change
Oecologia, 2006Co-Authors: Eelke Jongejans, Hans De Kroon, F BerendseAbstract:When perennial herbs face the risk of being outcompeted in the course of succession, they are hypothesized to either increase their biomass allocation to flowers and seeds or to invest more in vegetative growth. We tested these hypotheses in a 3-year garden experiment with four perennials (Hypochaeris radicata, Cirsium dissectum, Succisa pratensis and Centaurea jacea) by growing them in the midst of a tall tussock-forming grass (Molinia caerulea) that may successionally replace them in their natural habitat. In all species except for the short-lived H. radicata, costs of sexual reproduction were significant over the 3 years, since continuous bud removal enhanced total biomass or rosette number. To mimic succession we added nutrients, which resulted in a tripled grass biomass and higher death rates in the shorter-lived species. The simulated succession resulted also in a number of coupled growth responses in the survivors: enhanced plant size as well as elevated seed production. The latter was partly due to larger plant sizes, but mostly due to higher reproductive allocation, which in turn could be partly explained by lower relative somatic costs and by lower root–shoot ratios in the high-nutrient plots. Our results suggest that perennial plants can increase both their persistence and their colonization ability by simultaneously increasing their vegetative size and reproductive allocation in response to enhanced competition and nutrient influxes. These responses can be very important for the survival of a species in a metapopulation context.
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Bottlenecks and spatiotemporal variation in the sexual reproduction pathway of perennial meadow plants
Basic and Applied Ecology, 2006Co-Authors: Eelke Jongejans, Merel B. Soons, J.c.j.m. De KroonAbstract:Summary Sexual reproduction is important for the growth of populations and the maintenance of genetic diversity. Several steps are involved in the sexual reproduction pathway of plants: the production of flowers, the production of seeds and the establishment of seedlings from seeds. In this paper we quantify the relative importance and spatiotemporal variability of these different steps for four grassland perennials: Centaurea jacea , Cirsium dissectum , Hypochaeris radicata and Succisa pratensis . We compared undisturbed meadows with meadows where the top soil layer had been removed as a restoration measure. Data on the number of flower heads per flowering rosette, the numbers of flowers and seeds per flower head, and the seedling establishment probabilities per seed were collected by field observations and experiments in several sites and years. Combination of these data shows that H. radicata and S. pratensis have higher recruitment rates (1.9 and 3.3 seedlings per year per flowering rosette, respectively) than the more clonal C. dissectum and C. jacea (0.027 and 0.23, respectively). Seedling establishment is the major bottleneck for successful sexual reproduction in all species. Large losses also occurred due to failing seed set in C. dissectum . Comparison of the coefficients of variation per step in space and time revealed that spatiotemporal variability was largest in seedling establishment, followed closely by flower head production and seed set.
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Release thresholds strongly determine the range of seed dispersal by wind
Ecological Modelling, 2005Co-Authors: Peter Schippers, Eelke JongejansAbstract:Abstract The effect of the seed abscission process on the dispersal distance of seeds has never been studied explicitly and is often ignored in studies that aim to estimate the seed shadows of species. To examine the importance of the abscission process for the seed shadow we used a seed trajectory model that keeps track of the release threshold dynamics of the individual seeds on mother plant. We defined the release threshold as the critical wind speed that induces a mechanical force that is just large enough to release a seed from its mother plant. The model used real wind speed sequences and seed appearance over time on the mother plant. Several calculations were performed to investigate the effect of release thresholds dynamics on seed shadow of two herbaceous species with contrasting terminal velocity values ( V t ): Centaurea jacea ( V t = 4.1 m s −1 ) and Hypochaeris radicata ( V t = 0.49 m s −1 ). Release thresholds were responsible for a two-fold increase of median dispersal distances in both species. Tails of the seed shadows, the fraction of seeds that travel furthest, were even more sensitive and increased with a factor 4.5 for Centaurea and 7.0 for Hypochaeris . Our work indicates that the abscission process appears to be very important and suggests that dispersal distance of plants is currently severely underestimated, which, in turn, has major consequences for our current understanding of the distribution, metapopulation dynamics and survival of plant species.
Jonathan D Bakker - One of the best experts on this subject based on the ideXlab platform.
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intraspecific trait variation driven by plasticity and ontogeny in Hypochaeris radicata
PLOS ONE, 2014Co-Authors: Rachel M Mitchell, Jonathan D BakkerAbstract:The importance of intraspecific variation in plant functional traits for structuring communities and driving ecosystem processes is increasingly recognized, but mechanisms governing this variation are less studied. Variation could be due to adaptation to local conditions, plasticity in observed traits, or ontogeny. We investigated 1) whether abiotic stress caused individuals, maternal lines, and populations to exhibit trait convergence, 2) whether trait variation was primarily due to ecotypic differences or trait plasticity, and 3) whether traits varied with ontogeny. We sampled three populations of Hypochaeris radicata that differed significantly in rosette diameter and specific leaf area (SLA). We grew nine maternal lines from each population (27 lines total) under three greenhouse conditions: ambient conditions (control), 50% drought, or 80% shade. Plant diameter and relative chlorophyll content were measured throughout the experiment, and leaf shape, root:shoot ratio, and SLA were measured after five weeks. We used hierarchical mixed-models and variance component analysis to quantify differences in treatment effects and the contributions of population of origin and maternal line to observed variation. Observed variation in plant traits was driven primarily by plasticity. Shade significantly influenced all measured traits. Plant diameter was the only trait that had a sizable proportion of trait variation (30%) explained by population of origin. There were significant ontogenetic differences for both plant diameter and relative chlorophyll content. When subjected to abiotic stress in the form of light or water limitation, Hypochaeris radicata exhibited significant trait variability. This variation was due primarily to trait plasticity, rather than to adaptation to local conditions, and also differed with ontogeny.
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quantifying and comparing intraspecific functional trait variability a case study with Hypochaeris radicata
Functional Ecology, 2014Co-Authors: Rachel M Mitchell, Jonathan D BakkerAbstract:Summary 1. The importance of intraspecific trait variation is increasingly recognized, but the ways in which this variation is quantified and compared have not been rigorously assessed. 2. We reviewed 5 years of ecological literature quantifying intraspecific variation (64 published studies) and identified commonly applied statistical methods. Analysis of variance techniques (n = 43) was the most commonly applied method. Levene’s tests (n = 14), linear techniques (both general and generalized models) (n = 12) and mixed effects modelling (n = 9) were also used. Qualitative comparisons of plant phenotype using descriptive statistics (n = 10) and coefficients of variation (n = 8) were also applied. Bayesian analysis was used in a single study. 3. We compared the efficacy and interpretation of analysis of variance, tests for homogeneity of variance, qualitative comparisons, mixed effects models and Bayesian hierarchical modelling in a case study measuring variation in specific leaf area (SLA) and rosette diameter among 10 populations (n = 241 individuals) of Hypochaeris radicata. We also examined whether data base- and literature-based trait values provided good estimates for measured populations. 4. Intraspecific variation was substantial, and significant differences existed in both means and variation across populations for both measured traits. There was a 27-fold variation in SLA (1� 7–46� 1m m 2 mg � 1 ) and a 34-fold variation in rosette diameter (1� 7–59� 1 cm). The choice of statistical technique influenced the interpretation of results. Permutational ANOVA was reasonably successful in detecting differences among populations, particularly when combined with a permutational test of dispersion within populations. Only Bayesian estimates were able to simultaneously quantify and compare variation within and across populations and to estimate trait values and variation on a larger, regional scale. Literature-based trait values had poor fit for four of 10 populations and differed from the estimated regional trait distribution. 5. Synthesis. Although both classical and Bayesian techniques yielded similar results, Bayesian techniques were more sensitive to differences in intraspecific variation, could simultaneously examine variation within and across populations, could estimate regional trait distributions and did not require that the assumption of homogeneity of variance be met. Bayesian techniques and hierarchical models in particular represent a powerful analytical tool for studies of intraspecific variation.
S Paulsamy - One of the best experts on this subject based on the ideXlab platform.
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confertin and scopoletin from leaf and root extracts of Hypochaeris radicata have anti inflammatory and antioxidant activities
Industrial Crops and Products, 2015Co-Authors: S Jamuna, S Paulsamy, K Karthika, Krishnaswamy Thenmozhi, Subramanium Kathiravan, Rajendran VenkateshAbstract:Abstract Hypochaeris radicata is being prescribed by the local healers and Thoda tribals of Nilgiris, the Western Ghats, India for the treatment of inflammation and various other ailments. This study was designed to explore the anti-inflammatory and antioxidant effects of crude extracts, and the two isolated compounds, confertin and scopoletin from methanolic leaf and root extracts respectively in order to confirm the folkloric claim. Their effects were studied using carrageenan induced acute inflammation in rats. Indomethacin was used as the standard drug for comparison. Cytokine assay to measure the levels of proinflammatory mediators, TNF-α, IL-1β and IL-6 in serum was made. Histopathological and in vivo antioxidant studies were carried out using standard procedures. Therapeutic potential of the isolated compounds was further studied using PASS software. In acute inflammation, the isolated compounds showed more potent activity by inhibiting the paw oedema than the respective crude extracts. Furthermore, the compounds, confertin and scopoletin (10 mg/kg b.w.) suppressed the production of proinflammatory cytokines such as TNF-α, IL-1β and IL-6 and enhanced more prominent antioxidant activity, which was supported by histopathological observations. The obtained results, therefore, suggest that the compounds, confertin and scopoletin are prominent constituents of this species and they may be used as a remedy for inflammatory disorders.
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in vitro propagation and evaluation of antioxidant properties of the medicinal plant species Hypochaeris radicata l asteraceae distributed in nilgiris the western ghats
Asian Journal of Biomedical and Pharmaceutical Sciences, 2014Co-Authors: S Jamuna, S PaulsamyAbstract:In the recent years phytomedicines are employed for curing many diseases as alternative source of synthetic drugs due to many reasons; affordability, low price, no side effects and ecofriendly. Higher demand and hence over exploitation have depleted the plant sources severely. There is an urgent need to conserve the natural stalk by developing conservation strategies. Hypochaeris radicata, one such species needed in large quantity is severely exploited for its medicinal uses in high hills of Nilgiris, the Western Ghats, India. Further, no major scientific reports are available with respect to its bioactive compounds and therapeutic properties. To address this lacuna, the study was carried out to develop protocol for in vitro propagation, to know the phytochemicals by preliminary investigation and quantification and to evaluate the antioxidant properties. The results of the study report that higher number of shoots were obtained from cotyledonary leaf explants in the MS medium fortified with BAP at 2mg/L (100%) followed by BAP and GA3 at 2mg/L and 0.5mg/L (95.63%) respectively. Rooting percentage (98.48%) was better which subcultured onto the MS medium contained NAA at 1mg/L. Rooted plantlets were hardened (garden soil: sand: vermicompost=1:1:1) and established in pots with 75.22% survival rate. The determination of phytochemical constituents by qualitative and quantitative analysis revealed the presence of rich variety of secondary metabolites. The in vitro antioxidant activities of in vitro derived methanolic leaf extract of H. radicata proved this species as potential source for pharmaceutical drug preparations.
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phytochemical analysis and evaluation of leaf and root parts of the medicinal herb Hypochaeris radicata l for in vitro antioxidant activities
Asian pacific Journal of Tropical Biomedicine, 2014Co-Authors: Jamuna Senguttuvan, S Paulsamy, K KarthikaAbstract:Objective To analyse qualitative and quantitative phytochemical and evaluate in vitro antioxidant properties of various alcoholic and aqueous extracts of leaf and root parts of Hypochaeris radicata.
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in vitro antifungal activity of leaf and root extracts of the medicinal plant Hypochaeris radicata l
2013Co-Authors: Jamuna Senguttuvan, S Paulsamy, Karthika KrishnamoorthyAbstract:Objective: To assess the antifungal activity of the successive extracts (petroleum ether, chloroform, ethyl acetate, methanol and water) of leaf and root parts of Hypochaeris radicata and to determine the minimum inhibitory (MIC) concentration against nine human pathogenic fungi. Methods: The antifungal activities of the leaf and root extracts against nine pathogenic fungi were tested by using disc diffusion method. Tetracycline was used as positive control. MIC for the methanolic leaf and root extracts of this species was assessed for antifungal susceptibility using broth micro dilution method. Results: From the evaluation it was found that ethyl acetate extracts inhibited the fungal growth effectively than the other solvent extracts. The fungal species, Aspergillus niger and Mucor sp. were very sensitive to the ethyl acetate extract of both leaf (24.83 ± 0.28) and root (20.96 ± 0.25). Among the two parts studied, the root part showed higher antifungal activity than the leaf part. MIC for the methanolic leaf and root extracts of this species was ranging between 200 and 500µg/mL and 200 and 600µg/mL respectively. Conclusion: The obtained results provide a support for the use of this plant in traditional medicine and it is a potential antiseptic source for the prevention and treatment of fungal infections.
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in vitro antibacterial activity of leaf and root extracts of Hypochaeris radicata l asteraceae a medicinal plant species inhabiting the high hills of nilgiris the western ghats
2013Co-Authors: S Paulsamy, K KarthikaAbstract:The present study is focused onto investigate the antibacterial activity of different extracts (petroleum ether, chloroform, ethyl acetate, methanol and water) of leaf and root parts of the plant species, Hypochaeris radicata against certain both Gram-positive bacteria (Streptococcus faecalis, S. pyogenes, Enterococcus faecalis, Bacillus subtilis, B. thuringiensis and Staphylococcus aureus ) and Gram-negative bacteria (Seratia marcescens, Klebsiella pneumoniae, Proteus vulgaris, P. mirabilis, Salmonella paratyphi, S. parathypi A, S. paratyphi B, Pseudomonas aeruginosa and E. coli. ) by following agar disc diffusion method. Methanolic extract displayed broad spectrum of activity against all the test organisms than that of the other extracts. Among the extracts of two parts attempted, the methanolic root extract showed highest antibacterial activity (17.1 ± 0.1). The antibacterial activity of the methanolic extracts of both parts was comparable to that of the standard drug, ampicillin. The minimum inhibitory concentration (MIC) of the methanolic leaf and root extracts was determined by the broth dilution method and was ranging between 200 and 400μg/mL, and 200 and 600μg/mL respectively. The results of this study support the species, H. radicata for its antibacterial agent. The leaf and root extracts can be used to treat various skin and gastrointestinal infections in humans and so has good potential use in the food and cosmetic industries as well.
K Karthika - One of the best experts on this subject based on the ideXlab platform.
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confertin and scopoletin from leaf and root extracts of Hypochaeris radicata have anti inflammatory and antioxidant activities
Industrial Crops and Products, 2015Co-Authors: S Jamuna, S Paulsamy, K Karthika, Krishnaswamy Thenmozhi, Subramanium Kathiravan, Rajendran VenkateshAbstract:Abstract Hypochaeris radicata is being prescribed by the local healers and Thoda tribals of Nilgiris, the Western Ghats, India for the treatment of inflammation and various other ailments. This study was designed to explore the anti-inflammatory and antioxidant effects of crude extracts, and the two isolated compounds, confertin and scopoletin from methanolic leaf and root extracts respectively in order to confirm the folkloric claim. Their effects were studied using carrageenan induced acute inflammation in rats. Indomethacin was used as the standard drug for comparison. Cytokine assay to measure the levels of proinflammatory mediators, TNF-α, IL-1β and IL-6 in serum was made. Histopathological and in vivo antioxidant studies were carried out using standard procedures. Therapeutic potential of the isolated compounds was further studied using PASS software. In acute inflammation, the isolated compounds showed more potent activity by inhibiting the paw oedema than the respective crude extracts. Furthermore, the compounds, confertin and scopoletin (10 mg/kg b.w.) suppressed the production of proinflammatory cytokines such as TNF-α, IL-1β and IL-6 and enhanced more prominent antioxidant activity, which was supported by histopathological observations. The obtained results, therefore, suggest that the compounds, confertin and scopoletin are prominent constituents of this species and they may be used as a remedy for inflammatory disorders.
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phytochemical analysis and evaluation of leaf and root parts of the medicinal herb Hypochaeris radicata l for in vitro antioxidant activities
Asian pacific Journal of Tropical Biomedicine, 2014Co-Authors: Jamuna Senguttuvan, S Paulsamy, K KarthikaAbstract:Objective To analyse qualitative and quantitative phytochemical and evaluate in vitro antioxidant properties of various alcoholic and aqueous extracts of leaf and root parts of Hypochaeris radicata.
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in vitro antibacterial activity of leaf and root extracts of Hypochaeris radicata l asteraceae a medicinal plant species inhabiting the high hills of nilgiris the western ghats
2013Co-Authors: S Paulsamy, K KarthikaAbstract:The present study is focused onto investigate the antibacterial activity of different extracts (petroleum ether, chloroform, ethyl acetate, methanol and water) of leaf and root parts of the plant species, Hypochaeris radicata against certain both Gram-positive bacteria (Streptococcus faecalis, S. pyogenes, Enterococcus faecalis, Bacillus subtilis, B. thuringiensis and Staphylococcus aureus ) and Gram-negative bacteria (Seratia marcescens, Klebsiella pneumoniae, Proteus vulgaris, P. mirabilis, Salmonella paratyphi, S. parathypi A, S. paratyphi B, Pseudomonas aeruginosa and E. coli. ) by following agar disc diffusion method. Methanolic extract displayed broad spectrum of activity against all the test organisms than that of the other extracts. Among the extracts of two parts attempted, the methanolic root extract showed highest antibacterial activity (17.1 ± 0.1). The antibacterial activity of the methanolic extracts of both parts was comparable to that of the standard drug, ampicillin. The minimum inhibitory concentration (MIC) of the methanolic leaf and root extracts was determined by the broth dilution method and was ranging between 200 and 400μg/mL, and 200 and 600μg/mL respectively. The results of this study support the species, H. radicata for its antibacterial agent. The leaf and root extracts can be used to treat various skin and gastrointestinal infections in humans and so has good potential use in the food and cosmetic industries as well.
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screening of in vitro antioxidant activity of methanolic leaf and root extracts of Hypochaeris radicata l asteraceae
journal of applied pharmaceutical science, 2012Co-Authors: S Jamuna, S Paulsamy, K KarthikaAbstract:The aim of present study was to estimate the total phenolic and flavonoid contents and to investigate in vitro antioxidant potential of methanolic leaf and root extracts of the herb, Hypochaeris radicata L. (Asteraceae). Antioxidant activity was assessed by using 2,2diphenyl-1-picryl-hydrazyl (DPPH • ) assay, reducing power activity, [2,2’-azino-bis(3ethylbenzthiazoline-6-sulphonic acid)] ABTS •+ assay and ferrous ion chelating activity. Here, butylated hydroxytoluene (BHT), ascorbic acid (ASA), trolox and EDTA were used as standard antioxidants. The total phenolic and flavonoid contents were also determined and expressed in gallic acid and quercetin equivalent respectively. The results of the study indicate that the methanolic extracts of the leaf and root of H. radicata posses significant scavenging activity against DPPH • (97.99% for leaf and 96.44% for root at 250μg/ml each) and ferrous ions chelating activity (38.69% for leaf and 40.52% for root at 5000μg/ml each), reducing power activity (1.38 absorbance at 600µg/ml for leaf, 0.45 absorbance at 700 µg/ml for root) and free radical scavenging activity (ABTS •+ ) (2706.73 for leaf and 2028.37μmol for root TE/g). The free radical scavenging and antioxidant activities may be attributed to the presence of adequate phenolic (gallic acid content is 125.5µg/10mg in leaf and 133.06µg/10mg in root) and flavonoid compounds (105.76µg/2mg in leaf and 55.16µg/2mg in root). This study revealed that the methanolic extracts of both leaf and root of H. radicata has demonstrated significant antioxidant activity.
S Jamuna - One of the best experts on this subject based on the ideXlab platform.
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confertin and scopoletin from leaf and root extracts of Hypochaeris radicata have anti inflammatory and antioxidant activities
Industrial Crops and Products, 2015Co-Authors: S Jamuna, S Paulsamy, K Karthika, Krishnaswamy Thenmozhi, Subramanium Kathiravan, Rajendran VenkateshAbstract:Abstract Hypochaeris radicata is being prescribed by the local healers and Thoda tribals of Nilgiris, the Western Ghats, India for the treatment of inflammation and various other ailments. This study was designed to explore the anti-inflammatory and antioxidant effects of crude extracts, and the two isolated compounds, confertin and scopoletin from methanolic leaf and root extracts respectively in order to confirm the folkloric claim. Their effects were studied using carrageenan induced acute inflammation in rats. Indomethacin was used as the standard drug for comparison. Cytokine assay to measure the levels of proinflammatory mediators, TNF-α, IL-1β and IL-6 in serum was made. Histopathological and in vivo antioxidant studies were carried out using standard procedures. Therapeutic potential of the isolated compounds was further studied using PASS software. In acute inflammation, the isolated compounds showed more potent activity by inhibiting the paw oedema than the respective crude extracts. Furthermore, the compounds, confertin and scopoletin (10 mg/kg b.w.) suppressed the production of proinflammatory cytokines such as TNF-α, IL-1β and IL-6 and enhanced more prominent antioxidant activity, which was supported by histopathological observations. The obtained results, therefore, suggest that the compounds, confertin and scopoletin are prominent constituents of this species and they may be used as a remedy for inflammatory disorders.
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in vitro propagation and evaluation of antioxidant properties of the medicinal plant species Hypochaeris radicata l asteraceae distributed in nilgiris the western ghats
Asian Journal of Biomedical and Pharmaceutical Sciences, 2014Co-Authors: S Jamuna, S PaulsamyAbstract:In the recent years phytomedicines are employed for curing many diseases as alternative source of synthetic drugs due to many reasons; affordability, low price, no side effects and ecofriendly. Higher demand and hence over exploitation have depleted the plant sources severely. There is an urgent need to conserve the natural stalk by developing conservation strategies. Hypochaeris radicata, one such species needed in large quantity is severely exploited for its medicinal uses in high hills of Nilgiris, the Western Ghats, India. Further, no major scientific reports are available with respect to its bioactive compounds and therapeutic properties. To address this lacuna, the study was carried out to develop protocol for in vitro propagation, to know the phytochemicals by preliminary investigation and quantification and to evaluate the antioxidant properties. The results of the study report that higher number of shoots were obtained from cotyledonary leaf explants in the MS medium fortified with BAP at 2mg/L (100%) followed by BAP and GA3 at 2mg/L and 0.5mg/L (95.63%) respectively. Rooting percentage (98.48%) was better which subcultured onto the MS medium contained NAA at 1mg/L. Rooted plantlets were hardened (garden soil: sand: vermicompost=1:1:1) and established in pots with 75.22% survival rate. The determination of phytochemical constituents by qualitative and quantitative analysis revealed the presence of rich variety of secondary metabolites. The in vitro antioxidant activities of in vitro derived methanolic leaf extract of H. radicata proved this species as potential source for pharmaceutical drug preparations.
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screening of in vitro antioxidant activity of methanolic leaf and root extracts of Hypochaeris radicata l asteraceae
journal of applied pharmaceutical science, 2012Co-Authors: S Jamuna, S Paulsamy, K KarthikaAbstract:The aim of present study was to estimate the total phenolic and flavonoid contents and to investigate in vitro antioxidant potential of methanolic leaf and root extracts of the herb, Hypochaeris radicata L. (Asteraceae). Antioxidant activity was assessed by using 2,2diphenyl-1-picryl-hydrazyl (DPPH • ) assay, reducing power activity, [2,2’-azino-bis(3ethylbenzthiazoline-6-sulphonic acid)] ABTS •+ assay and ferrous ion chelating activity. Here, butylated hydroxytoluene (BHT), ascorbic acid (ASA), trolox and EDTA were used as standard antioxidants. The total phenolic and flavonoid contents were also determined and expressed in gallic acid and quercetin equivalent respectively. The results of the study indicate that the methanolic extracts of the leaf and root of H. radicata posses significant scavenging activity against DPPH • (97.99% for leaf and 96.44% for root at 250μg/ml each) and ferrous ions chelating activity (38.69% for leaf and 40.52% for root at 5000μg/ml each), reducing power activity (1.38 absorbance at 600µg/ml for leaf, 0.45 absorbance at 700 µg/ml for root) and free radical scavenging activity (ABTS •+ ) (2706.73 for leaf and 2028.37μmol for root TE/g). The free radical scavenging and antioxidant activities may be attributed to the presence of adequate phenolic (gallic acid content is 125.5µg/10mg in leaf and 133.06µg/10mg in root) and flavonoid compounds (105.76µg/2mg in leaf and 55.16µg/2mg in root). This study revealed that the methanolic extracts of both leaf and root of H. radicata has demonstrated significant antioxidant activity.