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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
151

Adolescents' perceptions of physical activity for the enhancement of health: a systematic review

Du Toit, Adele January 2012 (has links)
Adolescents are usually considered to be in good health, but their wellbeing tend to decrease from primary school to high school. When youth participate in at least 60 min of physical activity every day several health benefits accrue: healthy bones and muscles, improved muscular strength and endurance, reduced risk of developing chronic disease risk factors, improved self-esteem, as well as reduced stress and anxiety. Most youth, however, are not engaging in the recommended level of physical activity. Several studies report that adolescents’ general perception of health includes immediate issues like body awareness and not other health risks like osteoporosis, cholesterol and high blood pressure. The aim of this study was to firstly establish from the literature the main perceptions of physical activity for adolescents, and secondly to establish from the literature the main perceptions of physical activity in health enhancement for adolescents. The systematic review was, where possible, undertaken in line with the recommendations of the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions. The researchers independently reviewed the title and abstract of each reference to assess its eligibility. The full article was obtained for all potentially eligible references. After a review of the full article, 29 fulfilled the inclusion criteria for article 1 (chapter 2) and 17 articles for article 2 (chapter 3). From the results of the study it seemed that the main perceptions of physical activity for adolescents are influenced by cultural and social factors as well as parents’ beliefs. Perceptions youth have about physical activity will influence their participation in physical activity. Lastly, the results of this study demonstrate that there is a low level of knowledge and awareness regarding physical activity and health. The need to increase physical activity is a public health priority and therefore it is necessary to understand the factors that may influence their participation in order to promote physical activity among youth more effectively. / Thesis (MSc (Biokinetics))--North-West University, Potchefstroom Campus, 2013.
152

Liggaamsamestelling, groeivertraging en fisieke aktiwiteit van swart adolessente in 'n dorpsgemeenskap : PLAY studie / D. Naude

Naude, Dollien January 2010 (has links)
In South Africa a remarkable weight gain is found in black adolescent girls during mid-adolescence, which is not necessarily the case among boys (Kalk, 2001:577) . Anthropometry is one of the most basic methods for determining over-nutrition and malnutrition status. A considerable amount of research is indeed done on obesity, and quite an amount on growth stunting (OS), but few interventions exist for prevention and treatment of OS. The World Health Organization (WHO) has determined that approximately 230 million children world wide are growth stunted (OS) (WHO working group, 1986). Physical activity in children is affected by average or serious malnutrition and influences adolescents' body build and body composition (BC) because they are in a period of development. Hoffman et al. (2006), Mantsena et al. (2005) and Monyeki et al. (2005) have all found that OS children/adolescents are shorter in length and lighter in mass than adolescents that grow normally. But most OS adolescents have shown a higher skin fold-fat percentage as well as a higher body mass index (BMI). Intra-abdominal fat storage is also found in OS adolescents and children, which is a health risk. Cross sectional studies show that physical activity (p A) decrease with up to 50% during adolescence, which influences body composition. Research has indicated that a P A participation peak is reached between aged 13 and 14 years, when boys are more active than girls. What is less clear is how the pattern of adolescent obesity differs in terms of race, gender and age (Popkin & Udry, 1998). Firstly, the aim of this study was to determine what the nature of research is that has been undertaken regarding body composition (BC) of OS and malnourished adolescents in Africa and South America, by means of a literature study. The second aim was to determine which body composition variables best describe changes in BC in adolescents (13-18 years) after participation in a physical activity intervention. Thirdly, the aim was to determine which BC, relations and maturation differences are found between OS and non growth stunted (NOS) adolescents between ages 13 and 18 years. Finally, the aim was to establish whether the physical activity levels and physical activity patterns of adolescents (13 to 18 years) change congruent to age increase. The study was compiled by means of an availability sample by making use of two secondary black schools in Ikageng (Potchefstroom) in the North West Province. The availability sample comprised a control group and an experimental group of black learners each. The study was of a longitudinal study design nature which stretched from March 2004 to September 2006. Adolescents (N=309) in the North West Province (Potchefstroom, South Africa (158 boys, 211 girls) between ages 13 and 18 years were used in this study. All the learners were in grade 8 at the onset of the study 2004. The experimental group participated in a physical activity intervention programme for practically one hour, two days per week after school hours for twenty-three weeks in 2004 and in 2005 they practised three times per week for nineteen weeks (July school holiday excluded). Attendance percentage of the PA programme was noted according to attendance registers with the experimental group split into three categories, namely low (0%-30% attended), average (30%-60%) and high (60% and higher). The control group (N=87) attended no intervention program. BC, middle-to-hip ratio (MHR), body mass index (BMI), percentage body fat (% LV) and skin folds were measured for baseline and again after completion of the intervention programme. Maturation phase was determined by means of two gender specific questionnaires (Tanner Questionnaires). The Previous Physical Activity Recall (PDPAR), compiled by Trost et al. (1999), was used for the study to analyse the PA levels. Statistica (Statsoft Inc 9) and SAS (SAS Institute Inc, edition 8, Cary NC) computer processing packages were used to process the data collected. Descriptive statistics were used to represent BC components and participants. A Repeated measurements co-variance analysis (ANCOVA) (corrected for attendance percentage and gender) variance analysis (ANOVA) over time, with a Bonferroni post hoc analysis to establish how the different variables differ from each other over the various test period in months. The significance of differences found was set on p<0.05. Next the Mann-Whitney U test was applied to calculate the significant differences of certain variables between the GS and non-growth stunted (NGS) adolescents. The Chi-square test was also used to determine the categorical variables, namely differences in the distribution within the five Tanner phases, as well as the differences between the GS and NGS girls and boys separately, with regard to the distribution between the groups with a body fat percentage lower or higher than the median. The technique of multilevel modelling was used for analysing the change in PA data over time. The result gained from the literature clearly indicates that GS generally occurs in adolescents and children in developing countries. It was also found that physical activity is. beneficial to the adolescents in terms of body composition, especially for the boys. According to the body mass index (BM!) values, a small percentage of children are classified as overweight, whilst with methods such as the sum of skin folds calculation of skin fold fat percentage and %BF measured by means of air transfer pletismografie (ADP), a larger percentage of children was classified as "over fat". It has also been found that significant differences occurred between the mass, length, length-for-age-z-score (LOZ) , arm span, middle circumference, hip circumference and lean body mass of the GS (28 girls and 28 boys) and NGS (113 girls and 90 boys) groups. The results also indicated a difference in PA levels of boys in the experimental and control groups after participation in the P A programme. With increase in age and over time there was a decrease in weekend physical activity patterns in both groups (experimental and control) for both genders. The experimental group ended at higher PA level than that of the control group of boys over the 30.75 months period. Opposed to this the girls (152 and 59 subjects respectively) did indeed show significant differences during the week as well as during the weekend with the baseline measurements, whereas the experimental group initially showed higher PA levels. These differences were, however, not more significant during end measurements. Both groups of girls further showed a lower curve of PA than that of the boys. The experimental group of boys and girls, as well as the control groups displayed a decrease in PA over the 30.75 months period. With increase in age and over time, a decrease was observed in PA patterns in both groups for both genders, although the last two measurements showed a slight upward inclination, especially in the experimental group of boys. The results showed a difference in PA patterns in the boys in the experimental and control groups, which can be attributed to the PA intervention. From the literature overview the conclusion can be drawn that African countries and other developing countries, where food scarcity is more common, experience a larger extent of problems with GS. The occurrence of GS in South Africa is average. Hence it can be deduced that growth and development need to be taken into consideration when BC is determined in adolescents. Fat percentage is more sensitive measure of obesity than BMI following participation in a PA intervention programme in town community adolescents. Determining BF percentage by means of skin folds and air replacement pletismografie (ADP) is more accurate than BMI in this specific group of experimental subjects. From this study the conclusion can be drawn that differences occur between GS and NGS adolescents of both genders in certain BC and body proportion components, without a difference in sexual development. With regard to the girls in terms of PA levels, it had another effect as with the boys with the intervention. The experimental group of boys, after 3 years (of which they underwent a PA intervention for 2 years) showed a higher PA level than the control group of boys that did not participate in a PA intervention. From this it can be deduced that this intervention did indeed contribute to differences in PA of boys that participate in physical activity programmes in deprived environments, while strategies different from these will need to be developed for girls from these communities. / Thesis (Ph.D. (Human Movement Science))--North-West University, Potchefstroom Campus, 2010.
153

A Cross-Sectional Study of Chronic Impairments and Activity Limitations in Women at Least Six Months Post-Operative for Breast Cancer: An Exploratory Study.

Wong, Vicki 09 June 2014 (has links)
Objective: The increased survival rate amongst female breast cancer survivors creates a need for an understanding of chronic disability after surgery. The objective of this study is to explore the association between impairments (e.g., pain, mobility, strength) and the personality trait, fear of physical activity, and chronic daily activity limitations for women who had their surgery at least six months prior to the study. Hypothesis: The study hypothesis is that women with high levels of physical impairments and the personality trait of fear of physical activity will also have higher levels of daily activity limitations six months or more after their breast cancer surgery. Design: A cross-sectional design. Outcome Measures: Disabilities of Shoulder, Arm, and Hand (DASH), Visual Analog Scale for Pain (VAS-Pain), Fear Avoidance Belief Questionnaire – Physical Activity (FABQ-PA), and objective measures of shoulder mobility and strength. Participants: Women who had been diagnosed and undergone surgery for breast cancer, stage 1-3. They must have had their surgery at least six months previously and have completed chemotherapy or radiation therapy. Both English- and French-speaking women from the Ottawa-Gatineau region were eligible. Results: Data from twelve women were analysed with a mean age of 58.0±8.9 years and post-operative time of 4.0± 2.8 years. DASH scores mean was 12.2 ± 11.38. VAS-Pain (rs=0.819; p<.001), FABQ-Physical Activity (rs=0.746; p<.005) were significantly associated with DASH score, whereas non-significant associations were found with supraspinatus strength (rs = 0.182; p < .572) or infraspinatus strength (rs=0.553; p<.062) using the Spearman Rho test. Also, no significant relationships were observed between range of motion (hand-behind-back; p =.366; hand-behind-head; p=.390) and DASH scores using a Kruskal-Wallis test. Conclusion: The results of this exploratory study suggest that the reported daily activity limitations of women who have had breast cancer surgery may be related to the participant pain perception and/or fear of physical activity.
154

Liggaamsamestelling, groeivertraging en fisieke aktiwiteit van swart adolessente in 'n dorpsgemeenskap : PLAY studie / D. Naude

Naude, Dollien January 2010 (has links)
In South Africa a remarkable weight gain is found in black adolescent girls during mid-adolescence, which is not necessarily the case among boys (Kalk, 2001:577) . Anthropometry is one of the most basic methods for determining over-nutrition and malnutrition status. A considerable amount of research is indeed done on obesity, and quite an amount on growth stunting (OS), but few interventions exist for prevention and treatment of OS. The World Health Organization (WHO) has determined that approximately 230 million children world wide are growth stunted (OS) (WHO working group, 1986). Physical activity in children is affected by average or serious malnutrition and influences adolescents' body build and body composition (BC) because they are in a period of development. Hoffman et al. (2006), Mantsena et al. (2005) and Monyeki et al. (2005) have all found that OS children/adolescents are shorter in length and lighter in mass than adolescents that grow normally. But most OS adolescents have shown a higher skin fold-fat percentage as well as a higher body mass index (BMI). Intra-abdominal fat storage is also found in OS adolescents and children, which is a health risk. Cross sectional studies show that physical activity (p A) decrease with up to 50% during adolescence, which influences body composition. Research has indicated that a P A participation peak is reached between aged 13 and 14 years, when boys are more active than girls. What is less clear is how the pattern of adolescent obesity differs in terms of race, gender and age (Popkin & Udry, 1998). Firstly, the aim of this study was to determine what the nature of research is that has been undertaken regarding body composition (BC) of OS and malnourished adolescents in Africa and South America, by means of a literature study. The second aim was to determine which body composition variables best describe changes in BC in adolescents (13-18 years) after participation in a physical activity intervention. Thirdly, the aim was to determine which BC, relations and maturation differences are found between OS and non growth stunted (NOS) adolescents between ages 13 and 18 years. Finally, the aim was to establish whether the physical activity levels and physical activity patterns of adolescents (13 to 18 years) change congruent to age increase. The study was compiled by means of an availability sample by making use of two secondary black schools in Ikageng (Potchefstroom) in the North West Province. The availability sample comprised a control group and an experimental group of black learners each. The study was of a longitudinal study design nature which stretched from March 2004 to September 2006. Adolescents (N=309) in the North West Province (Potchefstroom, South Africa (158 boys, 211 girls) between ages 13 and 18 years were used in this study. All the learners were in grade 8 at the onset of the study 2004. The experimental group participated in a physical activity intervention programme for practically one hour, two days per week after school hours for twenty-three weeks in 2004 and in 2005 they practised three times per week for nineteen weeks (July school holiday excluded). Attendance percentage of the PA programme was noted according to attendance registers with the experimental group split into three categories, namely low (0%-30% attended), average (30%-60%) and high (60% and higher). The control group (N=87) attended no intervention program. BC, middle-to-hip ratio (MHR), body mass index (BMI), percentage body fat (% LV) and skin folds were measured for baseline and again after completion of the intervention programme. Maturation phase was determined by means of two gender specific questionnaires (Tanner Questionnaires). The Previous Physical Activity Recall (PDPAR), compiled by Trost et al. (1999), was used for the study to analyse the PA levels. Statistica (Statsoft Inc 9) and SAS (SAS Institute Inc, edition 8, Cary NC) computer processing packages were used to process the data collected. Descriptive statistics were used to represent BC components and participants. A Repeated measurements co-variance analysis (ANCOVA) (corrected for attendance percentage and gender) variance analysis (ANOVA) over time, with a Bonferroni post hoc analysis to establish how the different variables differ from each other over the various test period in months. The significance of differences found was set on p<0.05. Next the Mann-Whitney U test was applied to calculate the significant differences of certain variables between the GS and non-growth stunted (NGS) adolescents. The Chi-square test was also used to determine the categorical variables, namely differences in the distribution within the five Tanner phases, as well as the differences between the GS and NGS girls and boys separately, with regard to the distribution between the groups with a body fat percentage lower or higher than the median. The technique of multilevel modelling was used for analysing the change in PA data over time. The result gained from the literature clearly indicates that GS generally occurs in adolescents and children in developing countries. It was also found that physical activity is. beneficial to the adolescents in terms of body composition, especially for the boys. According to the body mass index (BM!) values, a small percentage of children are classified as overweight, whilst with methods such as the sum of skin folds calculation of skin fold fat percentage and %BF measured by means of air transfer pletismografie (ADP), a larger percentage of children was classified as "over fat". It has also been found that significant differences occurred between the mass, length, length-for-age-z-score (LOZ) , arm span, middle circumference, hip circumference and lean body mass of the GS (28 girls and 28 boys) and NGS (113 girls and 90 boys) groups. The results also indicated a difference in PA levels of boys in the experimental and control groups after participation in the P A programme. With increase in age and over time there was a decrease in weekend physical activity patterns in both groups (experimental and control) for both genders. The experimental group ended at higher PA level than that of the control group of boys over the 30.75 months period. Opposed to this the girls (152 and 59 subjects respectively) did indeed show significant differences during the week as well as during the weekend with the baseline measurements, whereas the experimental group initially showed higher PA levels. These differences were, however, not more significant during end measurements. Both groups of girls further showed a lower curve of PA than that of the boys. The experimental group of boys and girls, as well as the control groups displayed a decrease in PA over the 30.75 months period. With increase in age and over time, a decrease was observed in PA patterns in both groups for both genders, although the last two measurements showed a slight upward inclination, especially in the experimental group of boys. The results showed a difference in PA patterns in the boys in the experimental and control groups, which can be attributed to the PA intervention. From the literature overview the conclusion can be drawn that African countries and other developing countries, where food scarcity is more common, experience a larger extent of problems with GS. The occurrence of GS in South Africa is average. Hence it can be deduced that growth and development need to be taken into consideration when BC is determined in adolescents. Fat percentage is more sensitive measure of obesity than BMI following participation in a PA intervention programme in town community adolescents. Determining BF percentage by means of skin folds and air replacement pletismografie (ADP) is more accurate than BMI in this specific group of experimental subjects. From this study the conclusion can be drawn that differences occur between GS and NGS adolescents of both genders in certain BC and body proportion components, without a difference in sexual development. With regard to the girls in terms of PA levels, it had another effect as with the boys with the intervention. The experimental group of boys, after 3 years (of which they underwent a PA intervention for 2 years) showed a higher PA level than the control group of boys that did not participate in a PA intervention. From this it can be deduced that this intervention did indeed contribute to differences in PA of boys that participate in physical activity programmes in deprived environments, while strategies different from these will need to be developed for girls from these communities. / Thesis (Ph.D. (Human Movement Science))--North-West University, Potchefstroom Campus, 2010.
155

Physical activity assessed by accelerometry in children

Nilsson, Andreas January 2008 (has links)
Physical activity (PA) is likely to constitute an important aspect of health-related behaviour in growing children. However, the knowledge on levels and patterns of PA in children is limited, due to the difficulty of precisely measuring this complex behaviour in normal daily living. Information on variables that significantly contributes to the variability in PA patterns is warranted as it may inform strategies for promoting physically active lifestyles in school-age youth. The overall purpose of the present studies was to increase the knowledge about the use of accelerometry when assessing PA in children, and examine sources of variability in objectively assessed PA behaviour in children. The study samples included 1954 nine- and 15-year-old children from four geographical locations in Europe (Norway, Denmark, Estonia and Portugal), and additionally 16 Swedish seven-year-old boys and girls. PA was assessed by the MTI accelerometer during free-living conditions, including both weekdays and weekend days. A part of the PA assessment was conducted using different time sampling intervals (epochs). Predictions of estimates of daily energy expenditure from accelerometer output were calculated using previously published equations. Potential correlates of PA behaviour were assessed by self-report. The main findings were; a) the epoch setting had a significant effect when interpreting time spent at higher intensities of PA in young children, b) predicted energy expenditure differed substantially between equations, c) between- and within-day differences in overall levels of PA, time spent at moderate-to-vigorous intensity physical activity and time spent sedentary differed between age, gender and geographical location, d) outdoor play and sports participation were differentially associated with objectively measured PA in 9- and 15-year-old children. It is concluded that the sporadic nature of children’s physical activity require very short epoch settings for detecting high intensity PA, and that different published equations for estimations of daily energy expenditure cannot be used interchangeably. The interpretations of average energy expenditure from available equations should be made with caution. Based on a large sample of children of different ages, weekend days and leisure time during weekdays seem appropriate targets when promoting PA in order to increase the proportion of children achieving current recommendations on health enhancing PA. Further, significant correlates of PA behaviour dependent on age group are presented, which should be considered when planning interventions for promoting PA in school-age youth.
156

The implementation of the activity approach in Hong Kong /

Chung, Chak. January 1996 (has links)
Thesis (M. Ed.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 135-140).
157

The implementation of the activity approach in Hong Kong

Chung, Chak. January 1996 (has links)
Thesis (M.Ed.)--University of Hong Kong, 1996. / Includes bibliographical references (leaves 135-140). Also available in print.
158

Estudo químico e biológico de espécies dos gêneros Glandularia e Verbena nativas do sul do Brasil

Vestena, Angelica Signor January 2018 (has links)
As plantas medicinais são consideradas pela população uma alternativa para tratamento de diversas doenças. Entre estas, destacam-se as plantas da família Verbenaceae, como as espécies do gênero Verbena. Espécies reconhecidas atualmente como gênero Glandularia foram anteriormente descritas como Verbena. Esses gêneros ainda possuem problemas de circunscrição, tendo em vista que são táxons muitos semelhantes, sendo muitas vezes difícil diferenciá-los. Espécies de Verbena são bem relatadas na medicina popular quanto a atividade anti-inflamatória e para o tratamento de doenças hepáticas. Diante disso, objetivou-se com este trabalho o isolamento de compostos presentes em espécies dos gêneros Glandularia e Verbena e a avaliação das atividades hepatoprotetora e antiquimiotáxica de espécies de Verbena utilizadas na medicina popular. Os compostos isolados foram identificados através de técnicas cromatográficas e espectroscópicas. Extratos metanólicos de V. montevidensis e V. litoralis e o iridoide brasosídeo, presente em ambos os extratos, foram avaliados quanto a atividade antiquimiotáxica realizada de acordo com o teste modificado de Boyden e quanto a atividade hepatoprotetora e citotoxicidade in vitro realizado em células HepG2, pelos métodos de MTT e vermelho neutro. De G. selloi foram obtidos 6β-OH-ipolamiida e dois derivados de crisoeriol com estruturas inéditas, seloisídeo A e seloisídeo B. Do extrato das partes aéreas de G. lobata foram isolados verbascosídeo e o iridoide griselinosídeo, que foi também isolado de V. hirta e V. bonariensis. De V. montevidensis obteve-se brasosídeo. No ensaio biológico antiquimiotáxico realizado com o extrato metanólico de V. montevidensis e com brasosídeo, seu produto isolado, todas as amostras apresentaram inibição significativa da migração leucocitária em relação ao controle. Os resultados obtidos para citotoxicidade in vitro demonstram que os extratos metanólicos e brasosídeo, não apresentaram citotoxicidade nas concentrações testadas. Esses extratos demonstraram atividade hepatoprotetora, em células HepG2, após lesão induzida por etanol. Brasosídeo protegeu as células nas menores concentrações testadas, sugerindo que a atividade hepatoprotetora dos extratos esteja relacionada ao sinergismo entre este composto e verbascosídeo. Os resultados encontrados nos ensaios biológicos corroboram o uso popular de algumas espécies de Verbena como agentes hepatoprotetor e anti-inflamatório. / Medicinal plants are considered by the population an alternative to treat various diseases. Among these, stand out plants of the family Verbenaceae, such as the species of the genus Verbena. Species currently recognized as the genus Glandularia were previously described as Verbena. These genera still have problems of circumscription, since the taxa are very similar, being often difficult to differentiate them. Verbena species are well reported in folk medicine regarding anti-inflammatory activity and for the treatment of liver diseases. The objective of this work was the isolation of compounds present in species of the genera Glandularia and Verbena and the evaluation of the hepatoprotective and antichemotactic activities of Verbena species used in folk medicine. The isolated compounds were identified by chromatographic and spectroscopic techniques. Methanolic extracts of the V. montevidensis and V. litoralis and the iridoid brasoside, present in both extracts, were evaluated for the antichemotactic activity performed according to the modified Boyden test and for the hepatoprotective activity and in vitro cytotoxicity performed in HepG2, by MTT and neutral red methods. From G. selloi 6β-OH-ipolamiide and two chrysoeriol derivatives were obtained with novel structures, selloiside A and selloiside B. From the extract of the aerial parts of G. lobata verbascoside and the iridoid griselinoside were isolated. This iridoid was also isolated from V. hirta and V. bonariensis while V. montevidensis afforded brasoside. In the antichemotactic biological assay performed with the methanolic extract of V. montevidensis and with brasoside, all the samples showed significant inhibition of the leukocyte migration in relation to the control. The results obtained for in vitro cytotoxicity demonstrate that the methanolic extracts and brasoside did not present cytotoxicity at the concentrations tested. These extracts demonstrated hepatoprotective activity in HepG2 cells after ethanol-induced injury. Brasoside protected the cells at the lowest concentrations tested, suggesting that the hepatoprotective activity of the extracts is related to the synergism between this compound and verbascoside. The results found in the biological assays corroborate the popular use of some species of Verbena as hepatoprotective and anti-inflammatory agents.
159

Estudo químico e biológico de espécies dos gêneros Glandularia e Verbena nativas do sul do Brasil

Vestena, Angelica Signor January 2018 (has links)
As plantas medicinais são consideradas pela população uma alternativa para tratamento de diversas doenças. Entre estas, destacam-se as plantas da família Verbenaceae, como as espécies do gênero Verbena. Espécies reconhecidas atualmente como gênero Glandularia foram anteriormente descritas como Verbena. Esses gêneros ainda possuem problemas de circunscrição, tendo em vista que são táxons muitos semelhantes, sendo muitas vezes difícil diferenciá-los. Espécies de Verbena são bem relatadas na medicina popular quanto a atividade anti-inflamatória e para o tratamento de doenças hepáticas. Diante disso, objetivou-se com este trabalho o isolamento de compostos presentes em espécies dos gêneros Glandularia e Verbena e a avaliação das atividades hepatoprotetora e antiquimiotáxica de espécies de Verbena utilizadas na medicina popular. Os compostos isolados foram identificados através de técnicas cromatográficas e espectroscópicas. Extratos metanólicos de V. montevidensis e V. litoralis e o iridoide brasosídeo, presente em ambos os extratos, foram avaliados quanto a atividade antiquimiotáxica realizada de acordo com o teste modificado de Boyden e quanto a atividade hepatoprotetora e citotoxicidade in vitro realizado em células HepG2, pelos métodos de MTT e vermelho neutro. De G. selloi foram obtidos 6β-OH-ipolamiida e dois derivados de crisoeriol com estruturas inéditas, seloisídeo A e seloisídeo B. Do extrato das partes aéreas de G. lobata foram isolados verbascosídeo e o iridoide griselinosídeo, que foi também isolado de V. hirta e V. bonariensis. De V. montevidensis obteve-se brasosídeo. No ensaio biológico antiquimiotáxico realizado com o extrato metanólico de V. montevidensis e com brasosídeo, seu produto isolado, todas as amostras apresentaram inibição significativa da migração leucocitária em relação ao controle. Os resultados obtidos para citotoxicidade in vitro demonstram que os extratos metanólicos e brasosídeo, não apresentaram citotoxicidade nas concentrações testadas. Esses extratos demonstraram atividade hepatoprotetora, em células HepG2, após lesão induzida por etanol. Brasosídeo protegeu as células nas menores concentrações testadas, sugerindo que a atividade hepatoprotetora dos extratos esteja relacionada ao sinergismo entre este composto e verbascosídeo. Os resultados encontrados nos ensaios biológicos corroboram o uso popular de algumas espécies de Verbena como agentes hepatoprotetor e anti-inflamatório. / Medicinal plants are considered by the population an alternative to treat various diseases. Among these, stand out plants of the family Verbenaceae, such as the species of the genus Verbena. Species currently recognized as the genus Glandularia were previously described as Verbena. These genera still have problems of circumscription, since the taxa are very similar, being often difficult to differentiate them. Verbena species are well reported in folk medicine regarding anti-inflammatory activity and for the treatment of liver diseases. The objective of this work was the isolation of compounds present in species of the genera Glandularia and Verbena and the evaluation of the hepatoprotective and antichemotactic activities of Verbena species used in folk medicine. The isolated compounds were identified by chromatographic and spectroscopic techniques. Methanolic extracts of the V. montevidensis and V. litoralis and the iridoid brasoside, present in both extracts, were evaluated for the antichemotactic activity performed according to the modified Boyden test and for the hepatoprotective activity and in vitro cytotoxicity performed in HepG2, by MTT and neutral red methods. From G. selloi 6β-OH-ipolamiide and two chrysoeriol derivatives were obtained with novel structures, selloiside A and selloiside B. From the extract of the aerial parts of G. lobata verbascoside and the iridoid griselinoside were isolated. This iridoid was also isolated from V. hirta and V. bonariensis while V. montevidensis afforded brasoside. In the antichemotactic biological assay performed with the methanolic extract of V. montevidensis and with brasoside, all the samples showed significant inhibition of the leukocyte migration in relation to the control. The results obtained for in vitro cytotoxicity demonstrate that the methanolic extracts and brasoside did not present cytotoxicity at the concentrations tested. These extracts demonstrated hepatoprotective activity in HepG2 cells after ethanol-induced injury. Brasoside protected the cells at the lowest concentrations tested, suggesting that the hepatoprotective activity of the extracts is related to the synergism between this compound and verbascoside. The results found in the biological assays corroborate the popular use of some species of Verbena as hepatoprotective and anti-inflammatory agents.
160

Evaluation of antioxidant and antimicrobial activities of essential oils of leaves of Chemotype I, II and III of Lippia alba (Mill.) N. E. Brown. / AvaliaÃÃo das atividades antimicrobiana e antioxidante dos Ãleos essenciais das folhas dos quimiotipos I, II e III de Lippia alba (Mill.) N. E. Brown

AndrÃa Bessa Teixeira 31 August 2009 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / The species Lippia alba (erva cidreira) is widely used in folk medicine. The composition of essential oil varies quantitative and qualitative, leading to the classification of different chemotypes. A rich pharmacological potential is related to the wide variation in chemical composition of these oils, which arouses the interest of researchers in establishing scientific explanations for such activities. The objective of this study was to evaluate the antimicrobial and antioxidant activities of essential oils of chemotype I, II and III, leaves of L. alba, and to investigate their possible relationships with the chemical composition of their essential oils. The chemical characterization of constituents of essential oils was performed using GC-MS by determining the percentage of constituents present in the samples. The antimicrobial activity of oils was determined by agar diffusion, and MIC and CLM methods by microdilution broth culture and plated on agar, respectively. The antioxidant activity was assessed by measurement of TBARS and by determining the activity of removal of free radicals by DPPH. Essential oils from leaves of L. alba were recognized by the presence of its major constituents in chemotype I (citral-myrcene), chemotype II (citral-limonene) and chemotype III (carvone-limonene). The three essential oils showed activity against S. aureus, even resistant, and C. albicans. For Gram-negative bacteria, the three chemotypes present action on the A. lwoffi; the chemotypes II and III inhibited the growth of A. baumannii, and only the chemotype II was that acted on E. coli ATCC 10536. The lowest MIC obtained for CLM and essential oils of chemotypes I, II and III were 0,312 and 0,625mg/mL, 0,312 and 0,312mg/mL and 0,625 and 0,625mg/mL, respectively. The diffusion technique in agar served as a preliminary step in determining the antimicrobial activity and MIC determination by broth dilution accompanied by reading of optical densities of cultures showed absorbance values similar to the positive control group by a certain concentration and then increased indicating a higher microbial growth. Three chemotypes of OELA reduced lipid peroxidation induced in the hippocampus and brain of rats, but showed no scavenging activity of free radicals measured by the DPPH test. Thus, the results suggest that essential oils of chemotype I, II and III of L. alba, have excellent antimicrobial activity, especially on S. aureus and C. albicans, whereas the diffusion method is an excellent screening method, the dilution method, by visual inspection and reading of absorbance, in addition to determine the MIC, the CLM and evaluate the kinetics of inhibition of microbial growth, the antioxidant potential shown OELA by the hippocampus and cortex of rats makes these products a potential pharmacological tool in the treatment of neurodegenerative diseases, however, for that additional studies are needed, and that differences in the composition of the oil is a factor to be considered important in studies pharmacological. / A espÃcie Lippia alba (erva-cidreira) à muito usada na medicina popular. A composiÃÃo de seu Ãleo essencial apresenta variaÃÃes quantitativas e qualitativas, levando à classificaÃÃo de diferentes quimiotipos. Um rico potencial farmacolÃgico està relacionado à ampla variaÃÃo na composiÃÃo quÃmica desses Ãleos, o que desperta o interesse de pesquisadores em estabelecer explicaÃÃes cientÃficas para tais atividades. O objetivo do trabalho foi avaliar as atividades antimicrobiana e antioxidante dos Ãleos essenciais dos quimiotipo I, II e III, de folhas, de L. alba, bem como investigar suas possÃveis relaÃÃes com a composiÃÃo quÃmica de seus Ãleos essenciais. A caracterizaÃÃo quÃmica dos constituintes dos Ãleos essenciais foi realizada utilizando a CG-MS, determinando-se a porcentagem dos constituintes presentes nas amostras. O potencial antimicrobiano dos Ãleos foi determinado pelo mÃtodo de difusÃo em Ãgar, e as CIM e CLM pelos mÃtodos da microdiluiÃÃo em caldo de cultura e do plaqueamento em Ãgar, respectivamente. A atividade antioxidante foi avaliada pela dosagem de TBARS e pela determinaÃÃo da atividade de remoÃÃo de radicais livres pelo DPPH. Os Ãleos essenciais das folhas de L. alba foram reconhecidos pela presenÃa de seus constituintes majoritÃrios em quimiotipo I (citral-mirceno); quimiotipo II (citral-limoneno) e quimiotipo III (carvona-limoneno). Os trÃs Ãleos essenciais apresentaram atividade sobre S. aureus, mesmo as multirresistentes, e C. albicans. Para as bactÃrias Gram-negativas, os trÃs quimiotipos apresentaram aÃÃo sobre o A. lwoffi; os quimiotipos II e III inibiram o crescimento do A. baumannii; e apenas o quimiotipo II foi que teve aÃÃo sobre E. coli ATCC 10536. As mais baixas CIM e CLM obtidas para os Ãleos essenciais dos quimiotipos I, II e III, foram de 0,312 e 0,625mg/mL, 0,312 e 0,312mg/mL e 0,625 e 0,625mg/mL, respectivamente. A tÃcnica de difusÃo em Ãgar serviu como uma etapa preliminar na determinaÃÃo do potencial antimicrobiano e a determinaÃÃo da CIM por diluiÃÃo em caldo acompanhada de leitura das densidades Ãticas das culturas, mostrou valores de absorbÃncias semelhantes ao grupo controle positivo atà uma determinada concentraÃÃo e entÃo aumentaram, indicando um maior crescimento microbiano. Os trÃs quimiotipos do OELA reduziram a peroxidaÃÃo lipÃdica induzida no hipocampo e cÃrebro de ratos, contudo nÃo apresentaram atividade seqÃestradora de radicais livres mensuradas atravÃs do teste do DPPH. Assim, os resultados sugerem que os Ãleos essenciais dos quimiotipo I, II e III de L. alba, possuem excelente atividade antimicrobiana, principalmente sobre S.aureus e C. albicans; que o mÃtodo de difusÃo à um excelente mÃtodo de triagem; que o mÃtodo da diluiÃÃo, por inspeÃÃo visual e leitura de absorbÃncia, permite determinar alem da CIM, a CLM e avaliar a cinÃtica de inibiÃÃo de crescimento microbiano; o potencial antioxidante mostrado pelo OELA no hipocampo e cÃrtex de rato, torna esses produtos uma ferramenta farmacolÃgica em potencial no tratamento de doenÃas neurodegenerativas, contudo, para isso estudos adicionais sÃo necessÃrios; e que as diferenÃas na composiÃÃo do Ãleo à um fator que deve ser considerado importante nos estudos farmacolÃgicos.

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