Dr. Beate Pfundstein - Academia.edu (original) (raw)
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University of Tuscia (Università degli Studi della Tuscia, Viterbo)
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Papers by Dr. Beate Pfundstein
Journal of Agricultural and Food Chemistry, 2006
The antioxidant capacity of essential oils obtained by steam hydrodistillation from five species ... more The antioxidant capacity of essential oils obtained by steam hydrodistillation from five species of the genus Ocimum, namely Ocimum basilicum var. purpurascens, Ocimum basilicum, Ocimum gratissimum, Ocimum micranthum, and Ocimum tenuiflorum (syn. O. sanctum), were evaluated using a high-performance liquid chromatography-based hypoxanthine/xanthine oxidase and the DPPH assays. The yield of oils from the leaves of the five species was variable with the greater amount obtained from Ocimum gratissimum (3.5%) and the least from Ocimum basilicum var. purpurascens (0.5%). In the hypoxanthine/xanthine oxidase assay, strong antioxidant capacity was evident in all the oils but the greater was shown by that obtained from Ocimum tenuiflorum (syn. O. sanctum) (IC 50) 0.46 µL/mL) compared to Ocimum basilicum var. purpurascens (IC 50) 1.84 µL/mL). Antioxidant capacity was positively correlated (r) 0.92, p < 0.05) with a high proportion of compounds possessing a phenolic ring such as eugenol, while a strong negative correlation (r)-0.77, p > 0.1) with other major volatiles was observed. These correlations were confirmed to a large extent in the DPPH assay. The results of a 24 h experiment with Ocimum tenuiflorum (syn. O. sanctum) shows that the antioxidant capacity factor (amount of essential oil obtained × free radical scavenging capacity; mg × %/100) reaches a threshold between 10 and 12.00 h, corresponding to maximum sunlight intensity in Brasil and furthermore exhibits a clear diurnal variation. The data generated with Ocimum species indicates that essential oils obtained from various herbs and spices may have an important role to play in cancer chemoprevention, functional foods, and in the preservation of pharmacologic products.
Journal of Agricultural and Food Chemistry, 2014
Journal of Medicinal Food, 2010
Journal of Chromatography A, 1991
A simple method is described for the determination of primary and secondary amines in foodstuffs ... more A simple method is described for the determination of primary and secondary amines in foodstuffs by gas chromatography with a modified thermal energy analyser, operated in the nitrogen mode. Food samples were subjected to mineral oil vacuum distillation and the isolated amines were derivatized with benzenesulphonyl chloride to form the corresponding sulphonamides, which were fractionated to yield primary and secondary amine derivatives using a modified Hinsberg procedure. The detection limit for individual amines using a 10-g food sample was 10 micrograms/kg (ppb) and recoveries were in excess of 80%.
Journal of Agricultural and Food Chemistry, 2008
Journal of Agricultural and Food Chemistry, 2007
Journal of Cancer Research and Clinical Oncology, 1995
Without Abstract
Journal of Agricultural and Food Chemistry, 2006
The antioxidant capacity of essential oils obtained by steam hydrodistillation from five species ... more The antioxidant capacity of essential oils obtained by steam hydrodistillation from five species of the genus Ocimum, namely Ocimum basilicum var. purpurascens, Ocimum basilicum, Ocimum gratissimum, Ocimum micranthum, and Ocimum tenuiflorum (syn. O. sanctum), were evaluated using a high-performance liquid chromatography-based hypoxanthine/xanthine oxidase and the DPPH assays. The yield of oils from the leaves of the five species was variable with the greater amount obtained from Ocimum gratissimum (3.5%) and the least from Ocimum basilicum var. purpurascens (0.5%). In the hypoxanthine/xanthine oxidase assay, strong antioxidant capacity was evident in all the oils but the greater was shown by that obtained from Ocimum tenuiflorum (syn. O. sanctum) (IC 50) 0.46 µL/mL) compared to Ocimum basilicum var. purpurascens (IC 50) 1.84 µL/mL). Antioxidant capacity was positively correlated (r) 0.92, p < 0.05) with a high proportion of compounds possessing a phenolic ring such as eugenol, while a strong negative correlation (r)-0.77, p > 0.1) with other major volatiles was observed. These correlations were confirmed to a large extent in the DPPH assay. The results of a 24 h experiment with Ocimum tenuiflorum (syn. O. sanctum) shows that the antioxidant capacity factor (amount of essential oil obtained × free radical scavenging capacity; mg × %/100) reaches a threshold between 10 and 12.00 h, corresponding to maximum sunlight intensity in Brasil and furthermore exhibits a clear diurnal variation. The data generated with Ocimum species indicates that essential oils obtained from various herbs and spices may have an important role to play in cancer chemoprevention, functional foods, and in the preservation of pharmacologic products.
Journal of Agricultural and Food Chemistry, 2014
Journal of Medicinal Food, 2010
Journal of Chromatography A, 1991
A simple method is described for the determination of primary and secondary amines in foodstuffs ... more A simple method is described for the determination of primary and secondary amines in foodstuffs by gas chromatography with a modified thermal energy analyser, operated in the nitrogen mode. Food samples were subjected to mineral oil vacuum distillation and the isolated amines were derivatized with benzenesulphonyl chloride to form the corresponding sulphonamides, which were fractionated to yield primary and secondary amine derivatives using a modified Hinsberg procedure. The detection limit for individual amines using a 10-g food sample was 10 micrograms/kg (ppb) and recoveries were in excess of 80%.
Journal of Agricultural and Food Chemistry, 2008
Journal of Agricultural and Food Chemistry, 2007
Journal of Cancer Research and Clinical Oncology, 1995
Without Abstract