Nynke Brouwer - Academia.edu (original) (raw)

Papers by Nynke Brouwer

Research paper thumbnail of Australian Aboriginal people have used plants for food and me

Abstract: The Australian Aboriginal people have used plants as medicine and food for thousands of... more Abstract: The Australian Aboriginal people have used plants as medicine and food for thousands of years, however, this traditional knowledge is documented only to a limited extent, and is in danger of being lost. The Indigenous Bioresources Research Group (IBRG) aims to help Australian Aboriginal communities to preserve their customary medicinal knowledge, and to provide information that can be used for their cultural or educational purposes, as well as for scientific advancement. This work is undertaken in close collaboration with Australian Aboriginal communities in New South Wales. The project is multidisciplinary, combining an ethnobotanical and an ethnopharmacological approach, which includes biological and chemical investigations, as well as developing best practices for protecting traditional knowledge. This paper describes the general strategy of the project as well as methods used in the ethnopharmacological study. Ethnobotanical databases are set up for each participating ...

Research paper thumbnail of Bush Medicine Research Partnerships for Drug Discovery and Cultural Preservation

Research paper thumbnail of Green Bugs: Optimisation and Use of the Fluorescein Diacetate Antimicrobial Assay

Research paper thumbnail of Bioassay-Guided Fractionation of Alphitonia Excelsa

Research paper thumbnail of An Ethnopharmacological Study of Medicinal Plants in New South Wales

Molecules, 2005

The Australian Aboriginal people have used plants as medicine and food for thousands of years, ho... more The Australian Aboriginal people have used plants as medicine and food for thousands of years, however, this traditional knowledge is documented only to a limited extent, and is in danger of being lost. The Indigenous Bioresources Research Group (IBRG) aims to help Australian Aboriginal communities to preserve their customary medicinal knowledge, and to provide information that can be used for their cultural or educational purposes, as well as for scientific advancement. This work is undertaken in close collaboration with Australian Aboriginal communities in New South Wales. The project is multidisciplinary, combining an ethnobotanical and an ethnopharmacological approach, which includes biological and chemical investigations, as well as developing best practices for protecting traditional knowledge. This paper describes the general strategy of the project as well as methods used in the ethnopharmacological study. Ethnobotanical databases are set up for each participating community. Plant material is collected, extracted, and active compounds are isolated using a bioassay-guided fractionation approach. All extracts and compounds are tested for biological activity in antimicrobial assays (disc diffusion, resazurin, fluorescein Molecules 2005, 10 1253 diacetate), neurological assays or anti-inflammatory assays, depending on their traditional use.

Research paper thumbnail of Modification of the fluorescein diacetate assay for screening of antifungal agents against Candida albicans: Comparison with the NCCLS methods

Journal of Microbiological Methods, 2006

A modified fluorescein diacetate (FDA) assay has been compared with standard NCCLS broth macrodil... more A modified fluorescein diacetate (FDA) assay has been compared with standard NCCLS broth macrodilution and broth microdilution methods for the detection of antifungal activity. The FDA assay was performed in a medium containing bacteriological peptone, NaCl, yeast extract and glucose (0.2%, 0.1%, 0.1% and 1% w/v, respectively) and buffered with 10 mM BES buffer. The MICs of amphotericin B, fluconazole, miconazole and flucytosine (representing three major classes of antifungal agents) obtained by the three methods were compared. The results obtained with the FDA assays correlated well with the NCCLS macrodilution method for MICs of amphotericin B, miconazole and fluconazole, but not for flucytosine. However, the MIC values of flucytosine obtained with the FDA assay were well within the quality control range for the two reference strains recommended by the NCCLS. The FDA assay described is an attractive alternative to the NCCLS methods for screening for antifungal agents, with the added advantage of objectivity of fluorescence measurement.

Research paper thumbnail of Optimisation of the fluorescein diacetate antibacterial assay

Journal of Microbiological Methods, 2005

The fluorescein diacetate (FDA) antibacterial assay relies on the cleavage of fluorescein diaceta... more The fluorescein diacetate (FDA) antibacterial assay relies on the cleavage of fluorescein diacetate by metabolically active bacteria. The recent finding that microbiological media can lead to significant levels of cleavage has reduced the reliability of the assay. Using the nucleophilic scavengers N-ethylmaleimide and maleic anhydride, we have demonstrated that this abiotic cleavage is most likely due to nucleophiles such as cysteine and histidine commonly present in the media. To increase the reliability of the assay we have modified the original assay conditions to include use of dilute medium (peptone 0.2% w/v, yeast extract 0.1% w/v and NaCl 0.1% w/v) in a non-nucleophilic buffer and overnight incubation of the medium after addition of antibacterial agents. The optimised fluorescein diacetate assay has been used to determine the MIC of gentamicin, tetracycline and chloramphenicol for Escherichia coli, Staphyloccocus aureus and Pseudomonas aeruginosa and gave quantitative results that were reproducible and consistent with published data.

Research paper thumbnail of Alphitonia excelsa An ethnophamacological study

Research paper thumbnail of Yaegl bush resources handbook

Research paper thumbnail of Yaegl : Medicinal and Plant Resources Handbook

Research paper thumbnail of Yaegl: medicinal and plant resources handbook

Research paper thumbnail of Method for the extraction of the volatile compound salicylic acid from tobacco leaf material

In the analysis of SA in plant tissues, the extraction recovery is often very low and variable. T... more In the analysis of SA in plant tissues, the extraction recovery is often very low and variable. This is mainly caused by sublimation of SA, especially during evaporation of organic solvents. Techniques have been designed in order to overcome this problem. In the first part of the extraction procedure, sublimation of SA was prevented by addition of 0.2 M sodium hydroxide. At a later stage of the extraction procedure, sublimation of SA during solvent evaporation was controlled by the addition of a small amount of HPLC eluent. In this way, recoveries in the range of 71-91% for free SA and 65-79% for acid-hydrolysed SA were obtained. Recoveries could be further optimised by the use of an internal standard to correct for volume changes after the addition of the HPLC eluent.

Research paper thumbnail of Method for the extraction of the volatile compound salicylic acid from tobacco leaf material

Phytochemical Analysis, 2002

In the analysis of SA in plant tissues, the extraction recovery is often very low and variable. T... more In the analysis of SA in plant tissues, the extraction recovery is often very low and variable. This is mainly caused by sublimation of SA, especially during evaporation of organic solvents. Techniques have been designed in order to overcome this problem. In the first part of the extraction procedure, sublimation of SA was prevented by addition of 0.2 M sodium hydroxide. At a later stage of the extraction procedure, sublimation of SA during solvent evaporation was controlled by the addition of a small amount of HPLC eluent. In this way, recoveries in the range of 71-91% for free SA and 65-79% for acid-hydrolysed SA were obtained. Recoveries could be further optimised by the use of an internal standard to correct for volume changes after the addition of the HPLC eluent.

Research paper thumbnail of An Ethnopharmacological Study of Medicinal Plants in New South Wales

Molecules, 2005

The Australian Aboriginal people have used plants as medicine and food for thousands of years, ho... more The Australian Aboriginal people have used plants as medicine and food for thousands of years, however, this traditional knowledge is documented only to a limited extent, and is in danger of being lost. The Indigenous Bioresources Research Group (IBRG) aims to help Australian Aboriginal communities to preserve their customary medicinal knowledge, and to provide information that can be used for their cultural or educational purposes, as well as for scientific advancement. This work is undertaken in close collaboration with Australian Aboriginal communities in New South Wales. The project is multidisciplinary, combining an ethnobotanical and an ethnopharmacological approach, which includes biological and chemical investigations, as well as developing best practices for protecting traditional knowledge. This paper describes the general strategy of the project as well as methods used in the ethnopharmacological study. Ethnobotanical databases are set up for each participating community. Plant material is collected, extracted, and active compounds are isolated using a bioassay-guided fractionation approach. All extracts and compounds are tested for biological activity in antimicrobial assays (disc diffusion, resazurin, fluorescein Molecules 2005, 10 1253 diacetate), neurological assays or anti-inflammatory assays, depending on their traditional use.

Research paper thumbnail of Modification of the fluorescein diacetate assay for screening of antifungal agents against Candida albicans: Comparison with the NCCLS methods

Journal of Microbiological Methods, 2006

A modified fluorescein diacetate (FDA) assay has been compared with standard NCCLS broth macrodil... more A modified fluorescein diacetate (FDA) assay has been compared with standard NCCLS broth macrodilution and broth microdilution methods for the detection of antifungal activity. The FDA assay was performed in a medium containing bacteriological peptone, NaCl, yeast extract and glucose (0.2%, 0.1%, 0.1% and 1% w/v, respectively) and buffered with 10 mM BES buffer. The MICs of amphotericin B, fluconazole, miconazole and flucytosine (representing three major classes of antifungal agents) obtained by the three methods were compared. The results obtained with the FDA assays correlated well with the NCCLS macrodilution method for MICs of amphotericin B, miconazole and fluconazole, but not for flucytosine. However, the MIC values of flucytosine obtained with the FDA assay were well within the quality control range for the two reference strains recommended by the NCCLS. The FDA assay described is an attractive alternative to the NCCLS methods for screening for antifungal agents, with the added advantage of objectivity of fluorescence measurement.

Research paper thumbnail of Optimisation of the fluorescein diacetate antibacterial assay

Journal of Microbiological Methods, 2005

The fluorescein diacetate (FDA) antibacterial assay relies on the cleavage of fluorescein diaceta... more The fluorescein diacetate (FDA) antibacterial assay relies on the cleavage of fluorescein diacetate by metabolically active bacteria. The recent finding that microbiological media can lead to significant levels of cleavage has reduced the reliability of the assay. Using the nucleophilic scavengers N-ethylmaleimide and maleic anhydride, we have demonstrated that this abiotic cleavage is most likely due to nucleophiles such as cysteine and histidine commonly present in the media. To increase the reliability of the assay we have modified the original assay conditions to include use of dilute medium (peptone 0.2% w/v, yeast extract 0.1% w/v and NaCl 0.1% w/v) in a non-nucleophilic buffer and overnight incubation of the medium after addition of antibacterial agents. The optimised fluorescein diacetate assay has been used to determine the MIC of gentamicin, tetracycline and chloramphenicol for Escherichia coli, Staphyloccocus aureus and Pseudomonas aeruginosa and gave quantitative results that were reproducible and consistent with published data.

Research paper thumbnail of An ethnobotanical study of medicinal plants used by the local people of Alaşehir (Manisa) in Turkey

Background: Malaria remains one of the most important illnesses in sub-Saharan Africa. In Benin, ... more Background: Malaria remains one of the most important illnesses in sub-Saharan Africa. In Benin, it constitutes a major public health preoccupation particularly for children and pregnant women. Until now, population still mostly relies on herbal medicine for malaria healing. Hence this study was carried out to document the medicinal plants used in the plateau of Allada in Benin and to assess local knowledge on traditional medicine in the management of malaria and related symptoms. Materials and methods: Data were collected from 53 informants composed of 23 traditional healers and 30 medicinal plants sellers using a structured questionnaire. Results: A total of 82 plants species belonging to 78 genera in 43 plant families were recorded as antimalarial in the study area. The families of Rubiaceae and Caesalpiniaceae were the most represented with seven species each. High informant consensus factor (ICF) was recorded in the treatment of malaria (ICF ¼0.90). High fidelity level (FL ¼ 100%) was also recorded for 45.67% of the species used as antimalarial. Dichapetalum madagascariense was the species of high relative frequency of citation (RFC ¼ 0.81). The dominant plant parts used in the preparation of remedies were leaves (68%). The decoction (79%) was the main mode of preparation, while oral route (92%) was the principal route of remedies administration. Conclusion: This study provides plant species used in the plateau of Allada for malaria and related symptoms treatment. We hope that this study could be important for the conservation of traditional knowledge on the antimalarial plants and the improvement of malaria management. However, several plant species used as antimalarial by the traditional medicine practitioners in the study area need to be screened in order to identify the species having antiplasmodial activity.

Research paper thumbnail of Australian Aboriginal people have used plants for food and me

Abstract: The Australian Aboriginal people have used plants as medicine and food for thousands of... more Abstract: The Australian Aboriginal people have used plants as medicine and food for thousands of years, however, this traditional knowledge is documented only to a limited extent, and is in danger of being lost. The Indigenous Bioresources Research Group (IBRG) aims to help Australian Aboriginal communities to preserve their customary medicinal knowledge, and to provide information that can be used for their cultural or educational purposes, as well as for scientific advancement. This work is undertaken in close collaboration with Australian Aboriginal communities in New South Wales. The project is multidisciplinary, combining an ethnobotanical and an ethnopharmacological approach, which includes biological and chemical investigations, as well as developing best practices for protecting traditional knowledge. This paper describes the general strategy of the project as well as methods used in the ethnopharmacological study. Ethnobotanical databases are set up for each participating ...

Research paper thumbnail of Bush Medicine Research Partnerships for Drug Discovery and Cultural Preservation

Research paper thumbnail of Green Bugs: Optimisation and Use of the Fluorescein Diacetate Antimicrobial Assay

Research paper thumbnail of Bioassay-Guided Fractionation of Alphitonia Excelsa

Research paper thumbnail of An Ethnopharmacological Study of Medicinal Plants in New South Wales

Molecules, 2005

The Australian Aboriginal people have used plants as medicine and food for thousands of years, ho... more The Australian Aboriginal people have used plants as medicine and food for thousands of years, however, this traditional knowledge is documented only to a limited extent, and is in danger of being lost. The Indigenous Bioresources Research Group (IBRG) aims to help Australian Aboriginal communities to preserve their customary medicinal knowledge, and to provide information that can be used for their cultural or educational purposes, as well as for scientific advancement. This work is undertaken in close collaboration with Australian Aboriginal communities in New South Wales. The project is multidisciplinary, combining an ethnobotanical and an ethnopharmacological approach, which includes biological and chemical investigations, as well as developing best practices for protecting traditional knowledge. This paper describes the general strategy of the project as well as methods used in the ethnopharmacological study. Ethnobotanical databases are set up for each participating community. Plant material is collected, extracted, and active compounds are isolated using a bioassay-guided fractionation approach. All extracts and compounds are tested for biological activity in antimicrobial assays (disc diffusion, resazurin, fluorescein Molecules 2005, 10 1253 diacetate), neurological assays or anti-inflammatory assays, depending on their traditional use.

Research paper thumbnail of Modification of the fluorescein diacetate assay for screening of antifungal agents against Candida albicans: Comparison with the NCCLS methods

Journal of Microbiological Methods, 2006

A modified fluorescein diacetate (FDA) assay has been compared with standard NCCLS broth macrodil... more A modified fluorescein diacetate (FDA) assay has been compared with standard NCCLS broth macrodilution and broth microdilution methods for the detection of antifungal activity. The FDA assay was performed in a medium containing bacteriological peptone, NaCl, yeast extract and glucose (0.2%, 0.1%, 0.1% and 1% w/v, respectively) and buffered with 10 mM BES buffer. The MICs of amphotericin B, fluconazole, miconazole and flucytosine (representing three major classes of antifungal agents) obtained by the three methods were compared. The results obtained with the FDA assays correlated well with the NCCLS macrodilution method for MICs of amphotericin B, miconazole and fluconazole, but not for flucytosine. However, the MIC values of flucytosine obtained with the FDA assay were well within the quality control range for the two reference strains recommended by the NCCLS. The FDA assay described is an attractive alternative to the NCCLS methods for screening for antifungal agents, with the added advantage of objectivity of fluorescence measurement.

Research paper thumbnail of Optimisation of the fluorescein diacetate antibacterial assay

Journal of Microbiological Methods, 2005

The fluorescein diacetate (FDA) antibacterial assay relies on the cleavage of fluorescein diaceta... more The fluorescein diacetate (FDA) antibacterial assay relies on the cleavage of fluorescein diacetate by metabolically active bacteria. The recent finding that microbiological media can lead to significant levels of cleavage has reduced the reliability of the assay. Using the nucleophilic scavengers N-ethylmaleimide and maleic anhydride, we have demonstrated that this abiotic cleavage is most likely due to nucleophiles such as cysteine and histidine commonly present in the media. To increase the reliability of the assay we have modified the original assay conditions to include use of dilute medium (peptone 0.2% w/v, yeast extract 0.1% w/v and NaCl 0.1% w/v) in a non-nucleophilic buffer and overnight incubation of the medium after addition of antibacterial agents. The optimised fluorescein diacetate assay has been used to determine the MIC of gentamicin, tetracycline and chloramphenicol for Escherichia coli, Staphyloccocus aureus and Pseudomonas aeruginosa and gave quantitative results that were reproducible and consistent with published data.

Research paper thumbnail of Alphitonia excelsa An ethnophamacological study

Research paper thumbnail of Yaegl bush resources handbook

Research paper thumbnail of Yaegl : Medicinal and Plant Resources Handbook

Research paper thumbnail of Yaegl: medicinal and plant resources handbook

Research paper thumbnail of Method for the extraction of the volatile compound salicylic acid from tobacco leaf material

In the analysis of SA in plant tissues, the extraction recovery is often very low and variable. T... more In the analysis of SA in plant tissues, the extraction recovery is often very low and variable. This is mainly caused by sublimation of SA, especially during evaporation of organic solvents. Techniques have been designed in order to overcome this problem. In the first part of the extraction procedure, sublimation of SA was prevented by addition of 0.2 M sodium hydroxide. At a later stage of the extraction procedure, sublimation of SA during solvent evaporation was controlled by the addition of a small amount of HPLC eluent. In this way, recoveries in the range of 71-91% for free SA and 65-79% for acid-hydrolysed SA were obtained. Recoveries could be further optimised by the use of an internal standard to correct for volume changes after the addition of the HPLC eluent.

Research paper thumbnail of Method for the extraction of the volatile compound salicylic acid from tobacco leaf material

Phytochemical Analysis, 2002

In the analysis of SA in plant tissues, the extraction recovery is often very low and variable. T... more In the analysis of SA in plant tissues, the extraction recovery is often very low and variable. This is mainly caused by sublimation of SA, especially during evaporation of organic solvents. Techniques have been designed in order to overcome this problem. In the first part of the extraction procedure, sublimation of SA was prevented by addition of 0.2 M sodium hydroxide. At a later stage of the extraction procedure, sublimation of SA during solvent evaporation was controlled by the addition of a small amount of HPLC eluent. In this way, recoveries in the range of 71-91% for free SA and 65-79% for acid-hydrolysed SA were obtained. Recoveries could be further optimised by the use of an internal standard to correct for volume changes after the addition of the HPLC eluent.

Research paper thumbnail of An Ethnopharmacological Study of Medicinal Plants in New South Wales

Molecules, 2005

The Australian Aboriginal people have used plants as medicine and food for thousands of years, ho... more The Australian Aboriginal people have used plants as medicine and food for thousands of years, however, this traditional knowledge is documented only to a limited extent, and is in danger of being lost. The Indigenous Bioresources Research Group (IBRG) aims to help Australian Aboriginal communities to preserve their customary medicinal knowledge, and to provide information that can be used for their cultural or educational purposes, as well as for scientific advancement. This work is undertaken in close collaboration with Australian Aboriginal communities in New South Wales. The project is multidisciplinary, combining an ethnobotanical and an ethnopharmacological approach, which includes biological and chemical investigations, as well as developing best practices for protecting traditional knowledge. This paper describes the general strategy of the project as well as methods used in the ethnopharmacological study. Ethnobotanical databases are set up for each participating community. Plant material is collected, extracted, and active compounds are isolated using a bioassay-guided fractionation approach. All extracts and compounds are tested for biological activity in antimicrobial assays (disc diffusion, resazurin, fluorescein Molecules 2005, 10 1253 diacetate), neurological assays or anti-inflammatory assays, depending on their traditional use.

Research paper thumbnail of Modification of the fluorescein diacetate assay for screening of antifungal agents against Candida albicans: Comparison with the NCCLS methods

Journal of Microbiological Methods, 2006

A modified fluorescein diacetate (FDA) assay has been compared with standard NCCLS broth macrodil... more A modified fluorescein diacetate (FDA) assay has been compared with standard NCCLS broth macrodilution and broth microdilution methods for the detection of antifungal activity. The FDA assay was performed in a medium containing bacteriological peptone, NaCl, yeast extract and glucose (0.2%, 0.1%, 0.1% and 1% w/v, respectively) and buffered with 10 mM BES buffer. The MICs of amphotericin B, fluconazole, miconazole and flucytosine (representing three major classes of antifungal agents) obtained by the three methods were compared. The results obtained with the FDA assays correlated well with the NCCLS macrodilution method for MICs of amphotericin B, miconazole and fluconazole, but not for flucytosine. However, the MIC values of flucytosine obtained with the FDA assay were well within the quality control range for the two reference strains recommended by the NCCLS. The FDA assay described is an attractive alternative to the NCCLS methods for screening for antifungal agents, with the added advantage of objectivity of fluorescence measurement.

Research paper thumbnail of Optimisation of the fluorescein diacetate antibacterial assay

Journal of Microbiological Methods, 2005

The fluorescein diacetate (FDA) antibacterial assay relies on the cleavage of fluorescein diaceta... more The fluorescein diacetate (FDA) antibacterial assay relies on the cleavage of fluorescein diacetate by metabolically active bacteria. The recent finding that microbiological media can lead to significant levels of cleavage has reduced the reliability of the assay. Using the nucleophilic scavengers N-ethylmaleimide and maleic anhydride, we have demonstrated that this abiotic cleavage is most likely due to nucleophiles such as cysteine and histidine commonly present in the media. To increase the reliability of the assay we have modified the original assay conditions to include use of dilute medium (peptone 0.2% w/v, yeast extract 0.1% w/v and NaCl 0.1% w/v) in a non-nucleophilic buffer and overnight incubation of the medium after addition of antibacterial agents. The optimised fluorescein diacetate assay has been used to determine the MIC of gentamicin, tetracycline and chloramphenicol for Escherichia coli, Staphyloccocus aureus and Pseudomonas aeruginosa and gave quantitative results that were reproducible and consistent with published data.

Research paper thumbnail of An ethnobotanical study of medicinal plants used by the local people of Alaşehir (Manisa) in Turkey

Background: Malaria remains one of the most important illnesses in sub-Saharan Africa. In Benin, ... more Background: Malaria remains one of the most important illnesses in sub-Saharan Africa. In Benin, it constitutes a major public health preoccupation particularly for children and pregnant women. Until now, population still mostly relies on herbal medicine for malaria healing. Hence this study was carried out to document the medicinal plants used in the plateau of Allada in Benin and to assess local knowledge on traditional medicine in the management of malaria and related symptoms. Materials and methods: Data were collected from 53 informants composed of 23 traditional healers and 30 medicinal plants sellers using a structured questionnaire. Results: A total of 82 plants species belonging to 78 genera in 43 plant families were recorded as antimalarial in the study area. The families of Rubiaceae and Caesalpiniaceae were the most represented with seven species each. High informant consensus factor (ICF) was recorded in the treatment of malaria (ICF ¼0.90). High fidelity level (FL ¼ 100%) was also recorded for 45.67% of the species used as antimalarial. Dichapetalum madagascariense was the species of high relative frequency of citation (RFC ¼ 0.81). The dominant plant parts used in the preparation of remedies were leaves (68%). The decoction (79%) was the main mode of preparation, while oral route (92%) was the principal route of remedies administration. Conclusion: This study provides plant species used in the plateau of Allada for malaria and related symptoms treatment. We hope that this study could be important for the conservation of traditional knowledge on the antimalarial plants and the improvement of malaria management. However, several plant species used as antimalarial by the traditional medicine practitioners in the study area need to be screened in order to identify the species having antiplasmodial activity.