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Détail de l'auteur
Auteur Alvaro M. Viljoen
Documents disponibles écrits par cet auteur
Affiner la rechercheA comparative investigation of the antimicrobial properties of indigenous South African aromatic plants with popular commercially available essential oils / Sandy F. Van Vuuren in The journal of essential oil research, Vol. 18 N° Spécial (Juillet 2006)
in The journal of essential oil research > Vol. 18 N° Spécial (Juillet 2006) . - pp. 66-71
Titre : A comparative investigation of the antimicrobial properties of indigenous South African aromatic plants with popular commercially available essential oils Type de document : texte imprimé Auteurs : Sandy F. Van Vuuren, Auteur ; Alvaro M. Viljoen, Auteur Année de publication : 2013 Article en page(s) : pp. 66-71 Note générale : Génie Chimique Langues : Anglais (eng) Mots-clés : Myrothammus flabellifolius Myrothamnaceae Osmitopsis asteriscoides Artemisia afra Asteraceae Lippia javanica Verbenaceae Heteropyxis natalensis Heteropyxidaceae Lavender oil Thyme oil Tea tree oil Rosemary oil Peppermint oil Essential oil composition β-ocimene Linalool 1,8-cineole α-thujone Limonene β-thujone Artemisia ketone Camphor Pinocarvone Trans-pincarveol Antimicrobial activity Résumé : Essential oils have been accepted and recognized as having several therapeutic applications. Popular commercial oils such as lavender, rosemary, tea tree, thyme and peppermint have been used extensively in aromatherapy and as a treatment regimen against bacterial and fungal infections. Extensive studies on indigenous essential oils used in South African traditional healing rites indicate efficacy against a number of pathogens. By means of comparatively determining the MIC of the above-mentioned popular commercial oils against the essential oils of five indigenous plants (Myrothamnus flabellifolius, Osmitopsis asteriscoides, Heteropyxis natalensis, Artemisia afra and Lippiajavanica), efficacy was determined against eight bacterial reference strains and two yeast reference strains. The laboratory conditions and inoculum were standardized to ensure all 10 essential oils (commercial and indigenous) were evaluated under identical conditions. Where MIC data indicated coinciding values between commercial and indigenous oils, the MIC was further refined to narrow the increments. To comparatively demonstrate the time kill efficacy, commercial and indigenous oils were exposed to Staphylococcus aureus, Klebsiella pneunwniae and Candida albicans and the cidal efficacy plotted over time against the logarithm of viable colonies. Results indicate that South African indigenous essential oils compare favorably with commercial oils studied herein. Of all oils studied, Myrothamnus flabellifolius showed the most rapid cidal effect against all three pathogens tested. ISSN : 1041-2905 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=18019086 [article] A comparative investigation of the antimicrobial properties of indigenous South African aromatic plants with popular commercially available essential oils [texte imprimé] / Sandy F. Van Vuuren, Auteur ; Alvaro M. Viljoen, Auteur . - 2013 . - pp. 66-71.
Génie Chimique
Langues : Anglais (eng)
in The journal of essential oil research > Vol. 18 N° Spécial (Juillet 2006) . - pp. 66-71
Mots-clés : Myrothammus flabellifolius Myrothamnaceae Osmitopsis asteriscoides Artemisia afra Asteraceae Lippia javanica Verbenaceae Heteropyxis natalensis Heteropyxidaceae Lavender oil Thyme oil Tea tree oil Rosemary oil Peppermint oil Essential oil composition β-ocimene Linalool 1,8-cineole α-thujone Limonene β-thujone Artemisia ketone Camphor Pinocarvone Trans-pincarveol Antimicrobial activity Résumé : Essential oils have been accepted and recognized as having several therapeutic applications. Popular commercial oils such as lavender, rosemary, tea tree, thyme and peppermint have been used extensively in aromatherapy and as a treatment regimen against bacterial and fungal infections. Extensive studies on indigenous essential oils used in South African traditional healing rites indicate efficacy against a number of pathogens. By means of comparatively determining the MIC of the above-mentioned popular commercial oils against the essential oils of five indigenous plants (Myrothamnus flabellifolius, Osmitopsis asteriscoides, Heteropyxis natalensis, Artemisia afra and Lippiajavanica), efficacy was determined against eight bacterial reference strains and two yeast reference strains. The laboratory conditions and inoculum were standardized to ensure all 10 essential oils (commercial and indigenous) were evaluated under identical conditions. Where MIC data indicated coinciding values between commercial and indigenous oils, the MIC was further refined to narrow the increments. To comparatively demonstrate the time kill efficacy, commercial and indigenous oils were exposed to Staphylococcus aureus, Klebsiella pneunwniae and Candida albicans and the cidal efficacy plotted over time against the logarithm of viable colonies. Results indicate that South African indigenous essential oils compare favorably with commercial oils studied herein. Of all oils studied, Myrothamnus flabellifolius showed the most rapid cidal effect against all three pathogens tested. ISSN : 1041-2905 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=18019086
in The journal of essential oil research > Vol. 18 N° Spécial (Juillet 2006) . - pp. 124-128
Titre : Essential oil composition and in vitro biological activities of seven namibian species of Eriocephalus L. (Asteraceae) Type de document : texte imprimé Auteurs : Alvaro M. Viljoen, Auteur ; Elizabeth W. Njenga, Auteur ; Sandy F. Van Vuuren, Auteur Année de publication : 2013 Article en page(s) : pp. 124-128 Note générale : Génie Chimique Langues : Anglais (eng) Mots-clés : Eriocephalus dinteri Eriocephalus ericoides subsp. ericoides Eriocephalus klinghardtensis Eriocephalus luederitzianus Eriocephalus merxmuelleri Eriocephalus pinnatus Eriocephalus scariosus Asteraceae Namibia Essential oil composition Chemotaxonomy α-pinene β-pinene 1,8-cineole Santolina alcohol Linalool Chrysanthenone Camphor α-longipinene P-caryophyllene Antimicrobial activity Anti-inflammatory activity Résumé : The essential oil composition of seven Namibian Eriocephalus species (E. dinteri, E. ericoides subsp. ericoides, E. klinghardtensis, E. luederitzianus, E. merxmuelleri, E. pinnatus, E. scariosus) were determined by GC and GC/MS. The oils of E. ericoides subsp. ericoides (sample 1), E. merxmuelleri and E. scariosus were found to be rich in 1,8-cineole and camphor. Eriocephalus scariosus oil contained santolina alcohol (14.8%). The highest levels of camphor (38.4%) was found in E. dinteri oil. The major component of E. ericoides subsp. ericoides (sample 2) was linalool (10.4%). A chemical similarity between E. luederitzianus and E. klinghardtensis was observed which both accumulated high levels of α-pinene, β-pinene, p-cymene and γ-terpinene. Eriocephalus luederitzianus oil contained α-longipinene (10.3%) and β-caryophyllene (13.3%). The morphologically anomalous E. pinnatus was very different in oil composition when compared to the other taxa and is characterized by isoamyl 2-methylbutyrate (7.9%) and isoamyl valerate (6.5%). Antimicrobial disc diffusion assays and minimum inhibitory concentrations (MIC) were performed on all seven species. Good antifungal activity was noted for E. ericoides subsp. ericoides. Highest activities were noted for E. merxmuelleri against the Gram-positive test organisms and generally poor activity was noted against the Gram-negative test organisms for all species. The anti-inflammatory activity of the oils were assessed using the 5-lipoxygenase (5-LOX) enzyme and E. dinteri displayed the most promising inhibition (IC50 = 35 μg/ml). ISSN : 1041-2905 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=18019095 [article] Essential oil composition and in vitro biological activities of seven namibian species of Eriocephalus L. (Asteraceae) [texte imprimé] / Alvaro M. Viljoen, Auteur ; Elizabeth W. Njenga, Auteur ; Sandy F. Van Vuuren, Auteur . - 2013 . - pp. 124-128.
Génie Chimique
Langues : Anglais (eng)
in The journal of essential oil research > Vol. 18 N° Spécial (Juillet 2006) . - pp. 124-128
Mots-clés : Eriocephalus dinteri Eriocephalus ericoides subsp. ericoides Eriocephalus klinghardtensis Eriocephalus luederitzianus Eriocephalus merxmuelleri Eriocephalus pinnatus Eriocephalus scariosus Asteraceae Namibia Essential oil composition Chemotaxonomy α-pinene β-pinene 1,8-cineole Santolina alcohol Linalool Chrysanthenone Camphor α-longipinene P-caryophyllene Antimicrobial activity Anti-inflammatory activity Résumé : The essential oil composition of seven Namibian Eriocephalus species (E. dinteri, E. ericoides subsp. ericoides, E. klinghardtensis, E. luederitzianus, E. merxmuelleri, E. pinnatus, E. scariosus) were determined by GC and GC/MS. The oils of E. ericoides subsp. ericoides (sample 1), E. merxmuelleri and E. scariosus were found to be rich in 1,8-cineole and camphor. Eriocephalus scariosus oil contained santolina alcohol (14.8%). The highest levels of camphor (38.4%) was found in E. dinteri oil. The major component of E. ericoides subsp. ericoides (sample 2) was linalool (10.4%). A chemical similarity between E. luederitzianus and E. klinghardtensis was observed which both accumulated high levels of α-pinene, β-pinene, p-cymene and γ-terpinene. Eriocephalus luederitzianus oil contained α-longipinene (10.3%) and β-caryophyllene (13.3%). The morphologically anomalous E. pinnatus was very different in oil composition when compared to the other taxa and is characterized by isoamyl 2-methylbutyrate (7.9%) and isoamyl valerate (6.5%). Antimicrobial disc diffusion assays and minimum inhibitory concentrations (MIC) were performed on all seven species. Good antifungal activity was noted for E. ericoides subsp. ericoides. Highest activities were noted for E. merxmuelleri against the Gram-positive test organisms and generally poor activity was noted against the Gram-negative test organisms for all species. The anti-inflammatory activity of the oils were assessed using the 5-lipoxygenase (5-LOX) enzyme and E. dinteri displayed the most promising inhibition (IC50 = 35 μg/ml). ISSN : 1041-2905 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=18019095
in The journal of essential oil research > Vol. 18 N° Spécial (Juillet 2006) . - pp. 85-88
Titre : In vitro 5-lipoxygenase activity of three indigenous south african aromatic plants used in traditional healing and the stereospecific activity of limonene in the 5-lipoxygenase assay Type de document : texte imprimé Auteurs : Yakov Frum, Auteur ; Alvaro M. Viljoen, Auteur Année de publication : 2013 Article en page(s) : pp. 85-88 Note générale : Génie Chimique Langues : Anglais (eng) Mots-clés : Helichrysum odoratissimum Asteraceae Heteropyxis natalensis Heteropyxidaceae Lippiajawanica Verbenaceae Essential oil composition Limonene Linalool 1,8-cineole (Z)-β-ocimene 5-lipoxygenase Anti-inflammatory Résumé : An investigation was .undertaken to determine the 5-lipoxygenase inhibitory activity of aromatic plants traditionally used to treat dermatological pathologies. Guided by ethnobotanical literature and availability from natural sources, the essential oils of Helichrysum odoratissimum (L.) Less., Heteropyxis natalensis Harv. and Lippia javanica (Burm. f.) Spreng. were collected. The hydrodistilled essential oils displayed promising 5-lipoxygenase inhibitory activity with IC50 values between 35 and 75 ppm. The oil compositions were determined by GC and GC/MS. Major compounds possibly contributing to the anti-inflammatory activity include β-caryophyllene, 1,8-cineole and limonene. Enantiomers and racemic mixtures of limonene displayed significantly different 5-lipoxygenase inhibitory activity suggesting stereoselectivity of the enzyme-catalyzed reaction. Furthermore, the monoterpene 1,8-cineole appeared to cause partial potentiation of the anti-inflammatory activity displayed by limonene. ISSN : 1041-2905 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=18019089 [article] In vitro 5-lipoxygenase activity of three indigenous south african aromatic plants used in traditional healing and the stereospecific activity of limonene in the 5-lipoxygenase assay [texte imprimé] / Yakov Frum, Auteur ; Alvaro M. Viljoen, Auteur . - 2013 . - pp. 85-88.
Génie Chimique
Langues : Anglais (eng)
in The journal of essential oil research > Vol. 18 N° Spécial (Juillet 2006) . - pp. 85-88
Mots-clés : Helichrysum odoratissimum Asteraceae Heteropyxis natalensis Heteropyxidaceae Lippiajawanica Verbenaceae Essential oil composition Limonene Linalool 1,8-cineole (Z)-β-ocimene 5-lipoxygenase Anti-inflammatory Résumé : An investigation was .undertaken to determine the 5-lipoxygenase inhibitory activity of aromatic plants traditionally used to treat dermatological pathologies. Guided by ethnobotanical literature and availability from natural sources, the essential oils of Helichrysum odoratissimum (L.) Less., Heteropyxis natalensis Harv. and Lippia javanica (Burm. f.) Spreng. were collected. The hydrodistilled essential oils displayed promising 5-lipoxygenase inhibitory activity with IC50 values between 35 and 75 ppm. The oil compositions were determined by GC and GC/MS. Major compounds possibly contributing to the anti-inflammatory activity include β-caryophyllene, 1,8-cineole and limonene. Enantiomers and racemic mixtures of limonene displayed significantly different 5-lipoxygenase inhibitory activity suggesting stereoselectivity of the enzyme-catalyzed reaction. Furthermore, the monoterpene 1,8-cineole appeared to cause partial potentiation of the anti-inflammatory activity displayed by limonene. ISSN : 1041-2905 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=18019089
in The journal of essential oil research > Vol. 18 N° Spécial (Juillet 2006) . - pp. 30-36
Titre : A seasonal variation study of the chemical composition and antimicrobial activity of the essential oil of Agathosma ovata (Thunb.) pillans (Rutaceae) Type de document : texte imprimé Auteurs : Alvaro M. Viljoen, Auteur ; Aneesa Moolla, Auteur ; Sandy F. Van Vuuren, Auteur Année de publication : 2013 Article en page(s) : pp. 30-36 Note générale : Génie Chimique Langues : Anglais (eng) Mots-clés : Agathosnw ovata Rutaceae Buchu Essential oil composition Sabinene p-cymene Terpinen-4-ol α-pinene α- thujene Myrcene Limonene Linalool Antimicrobial activity Résumé : A seasonal variation study was performed on the chemical composition of the essential oil of Agathosma ovata (Rutaceae). In addition, this study looked at how variations may impact the antimicrobial activity of A. ovata. The chemical composition of 10 monthly samples, as determined by GC and GC/MS, were found to differ qualitatively and quantitatively and the analysis resulted in the identification of 144 compounds. Sabinene was the major compound in the oil and ranged between 25-44% over the year. The antimicrobial activity was evaluated using the minimum inhibitory concentration (MIC) method on four pathogens, i.e. Staphylococcus aureus, Bacillus cereus, Klebsiella pneumoniae and Candida albicans. Most ofthe samples had MIC values of 8 mg/mL. The activity for Staphylococcus aureus showed the greatest fluctuation (1.5-14 mg/mL) over the seasonal period. ISSN : 1041-2905 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=18019078 [article] A seasonal variation study of the chemical composition and antimicrobial activity of the essential oil of Agathosma ovata (Thunb.) pillans (Rutaceae) [texte imprimé] / Alvaro M. Viljoen, Auteur ; Aneesa Moolla, Auteur ; Sandy F. Van Vuuren, Auteur . - 2013 . - pp. 30-36.
Génie Chimique
Langues : Anglais (eng)
in The journal of essential oil research > Vol. 18 N° Spécial (Juillet 2006) . - pp. 30-36
Mots-clés : Agathosnw ovata Rutaceae Buchu Essential oil composition Sabinene p-cymene Terpinen-4-ol α-pinene α- thujene Myrcene Limonene Linalool Antimicrobial activity Résumé : A seasonal variation study was performed on the chemical composition of the essential oil of Agathosma ovata (Rutaceae). In addition, this study looked at how variations may impact the antimicrobial activity of A. ovata. The chemical composition of 10 monthly samples, as determined by GC and GC/MS, were found to differ qualitatively and quantitatively and the analysis resulted in the identification of 144 compounds. Sabinene was the major compound in the oil and ranged between 25-44% over the year. The antimicrobial activity was evaluated using the minimum inhibitory concentration (MIC) method on four pathogens, i.e. Staphylococcus aureus, Bacillus cereus, Klebsiella pneumoniae and Candida albicans. Most ofthe samples had MIC values of 8 mg/mL. The activity for Staphylococcus aureus showed the greatest fluctuation (1.5-14 mg/mL) over the seasonal period. ISSN : 1041-2905 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=18019078
in The journal of essential oil research > Vol. 18 N° Spécial (Juillet 2006) . - pp. 2-16
Titre : The biological activity and essential oil composition of 17 agathosma (Rutaceae) species Type de document : texte imprimé Auteurs : Alvaro M. Viljoen, Auteur ; Aneesa Moolla, Auteur ; Sandy F. Van Vuuren, Auteur Année de publication : 2013 Article en page(s) : pp. 2-16 Note générale : Génie Chimique Langues : Anglais (eng) Mots-clés : Agathosma arida Agathosma bathii Agathosma hetulina Agathosma capensis Agathosnw collina Agathosma crenulata Agathosnw hirsuta Agathosma lanata Agathosnw namaquensis Agathosma ovalifolia Agathosma ovata Agathosnw parva Agathosma pubigera Agathosma pungens Agathosnw roodebergensis Agathosma stipitata Agathosma zwarthergense Rutaceae Buchu Essential oil composition Sabinene Linalool β-pinene Menthone Isomenthone Pulegone Myrcene Limonene p-phellandrene Neral Geranial α-pinene 1,8-cineole Citronellal Linalool Methyl citronellate Antimicrobial activity Anti-inflammatory Toxicity Résumé : The essential oil composition, antimicrobial, anti-inflammatory and cytotoxic activities of 17 indigenous Agathosnw species (18 samples) were investigated in order to validate their use in traditional healing. The results were related to the chemical composition of the essential oils as determined by GC and GC/MS. The antimicrobial activity was evaluated using the minimum inhibitory concentration (MIC) method on four pathogens: Staphylococcus aureus (ATCC 12600), Bacillus cereus (ATCC 11778), Klebsiella pneumoniae (NCTC 9633) and Candida albicans (ATCC 10231). The anti-inflammatory activity was evaluated using the 5-lipoxygenase assay while the cytotoxic activity was determined using the MTT (3-[4,5-dimethyl-2-thiazol-yl]-2,5-diphenyl-2H-tetrazolium bromide) cellular viability assay. The antimicrobial assay revealed that the most active oil against C. albicans was A. collina (MIC value of 3 mg/mL) whilst the most active oils against B. cereus were A. crenulata and A. pungens (MIC values of 3 mg/mL). Nine of the species had MIC values of 4 mg/mL against the Gram-positive pathogen S. aureus. The oils showed less activity against the Gram-negative pathogen K pneumoniae. All the oils exhibited good in vitro anti-inflammatory activity with A. collina being the most potent (IC50 value of 25.98 ± 1.83 μg/mL). The results show that the oils were strong inhibitors of the enzyme 5-lipoxygenase. The oils proved to be toxic in the MTT assay displaying IC50 values of < 0.0001 μg/mL, which were relatively toxic when compared to a plant-derived compound such as quinine (IC50 value of 0.08 ± 0.03 μg/mL). The results revealed some relationships between the major components, some bioactivities and toxicities. The oils were found to differ qualitatively and quantitatively in compositions and their analysis resulted in the identification of a total of 322 compounds in 18 of the samples. ISSN : 1041-2905 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=18019074 [article] The biological activity and essential oil composition of 17 agathosma (Rutaceae) species [texte imprimé] / Alvaro M. Viljoen, Auteur ; Aneesa Moolla, Auteur ; Sandy F. Van Vuuren, Auteur . - 2013 . - pp. 2-16.
Génie Chimique
Langues : Anglais (eng)
in The journal of essential oil research > Vol. 18 N° Spécial (Juillet 2006) . - pp. 2-16
Mots-clés : Agathosma arida Agathosma bathii Agathosma hetulina Agathosma capensis Agathosnw collina Agathosma crenulata Agathosnw hirsuta Agathosma lanata Agathosnw namaquensis Agathosma ovalifolia Agathosma ovata Agathosnw parva Agathosma pubigera Agathosma pungens Agathosnw roodebergensis Agathosma stipitata Agathosma zwarthergense Rutaceae Buchu Essential oil composition Sabinene Linalool β-pinene Menthone Isomenthone Pulegone Myrcene Limonene p-phellandrene Neral Geranial α-pinene 1,8-cineole Citronellal Linalool Methyl citronellate Antimicrobial activity Anti-inflammatory Toxicity Résumé : The essential oil composition, antimicrobial, anti-inflammatory and cytotoxic activities of 17 indigenous Agathosnw species (18 samples) were investigated in order to validate their use in traditional healing. The results were related to the chemical composition of the essential oils as determined by GC and GC/MS. The antimicrobial activity was evaluated using the minimum inhibitory concentration (MIC) method on four pathogens: Staphylococcus aureus (ATCC 12600), Bacillus cereus (ATCC 11778), Klebsiella pneumoniae (NCTC 9633) and Candida albicans (ATCC 10231). The anti-inflammatory activity was evaluated using the 5-lipoxygenase assay while the cytotoxic activity was determined using the MTT (3-[4,5-dimethyl-2-thiazol-yl]-2,5-diphenyl-2H-tetrazolium bromide) cellular viability assay. The antimicrobial assay revealed that the most active oil against C. albicans was A. collina (MIC value of 3 mg/mL) whilst the most active oils against B. cereus were A. crenulata and A. pungens (MIC values of 3 mg/mL). Nine of the species had MIC values of 4 mg/mL against the Gram-positive pathogen S. aureus. The oils showed less activity against the Gram-negative pathogen K pneumoniae. All the oils exhibited good in vitro anti-inflammatory activity with A. collina being the most potent (IC50 value of 25.98 ± 1.83 μg/mL). The results show that the oils were strong inhibitors of the enzyme 5-lipoxygenase. The oils proved to be toxic in the MTT assay displaying IC50 values of < 0.0001 μg/mL, which were relatively toxic when compared to a plant-derived compound such as quinine (IC50 value of 0.08 ± 0.03 μg/mL). The results revealed some relationships between the major components, some bioactivities and toxicities. The oils were found to differ qualitatively and quantitatively in compositions and their analysis resulted in the identification of a total of 322 compounds in 18 of the samples. ISSN : 1041-2905 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=18019074
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