A5002032125- Phytochemicals and Antioxidant Activities
- Fermentation and Sensory Analysis
- Analytical Chemistry and Chromatography
- Ethnobotanical and Medicinal Plants Studies
- Mass Spectrometry Techniques and Applications
- Mycotoxins in Agriculture and Food
- Metabolomics and Mass Spectrometry Studies
- Essential Oils and Antimicrobial Activity
- Chromatography in Natural Products
- African Botany and Ecology Studies
- Hormonal and reproductive studies
- Biochemical Analysis and Sensing Techniques
- Tea Polyphenols and Effects
- Natural Compound Pharmacology Studies
- Antimicrobial Peptides and Activities
- Pomegranate: compositions and health benefits
- Insect and Pesticide Research
- Meat and Animal Product Quality
- Plant biochemistry and biosynthesis
- Horticultural and Viticultural Research
- Pharmacological Effects of Medicinal Plants
- Plant Pathogens and Fungal Diseases
- Plant and fungal interactions
- Cannabis and Cannabinoid Research
- Chemical synthesis and alkaloids
Stellenbosch University
2015-2024
Columbus Oncology and Hematology Associates
2020
University of Cape Town
2020
University of Florida
2020
Analytical Services
2011
Agricultural institute of Slovenia
2007
North-West University
2000-2001
Zentralklinik Bad Berka
1998
Cyclopia subternata plants are traditionally used for the production of South African herbal tea, honeybush, and recently as aqueous extracts food industry. A C. extract mangiferin (a major constituent) known to have anti-diabetic properties. Variation in phenolic composition antioxidant capacity is expected due cultivation largely from seedlings, having implications standardization quality control. Aqueous 64 seedlings same age, cultivated under environmental conditions, were analyzed...
A high-performance liquid chromatographic (HPLC) method coupled with diode-array detection (DAD) was optimized for the qualitative analysis of aqueous extracts Cyclopia genistoides. Comprehensive insight into phenolic profile unfermented and fermented sample achieved identification ten compounds based on comparison authentic reference standards tentative 30 additional by means electrospray ionization mass spectrometry (ESI-MS) tandem MS detection. Three iriflophenone-di-O,C-hexoside isomers,...
Tea samples from 17 populations of "wild tea" ecotypes Aspalathus linearis (rooibos tea) and 2 pendula were analyzed. Recent advances in column technology together with high-resolution mass spectrometry applied to improve resolution, facilitating the identification several new compounds as well grouping wild tea according their chemical composition. The collisional cross-section data obtained ion mobility-mass is reported for flavonoids rooibos first time. Enzyme pathways synthesis unique...
Changes in anthocyanin chemistry represent some of the most important transformations involved red wine aging. However, accurate analysis derived pigments, as required to study evolution anthocyanins and tannins during aging, is hampered by their extreme structural diversity, low levels, fact that many these compounds have identical mass spectral characteristics. In this context, chromatographic separation critical. contribution, application online hydrophilic interaction chromatography...
Comprehensive two-dimensional liquid chromatography (LC × LC) and ion mobility spectrometry–mass spectrometry (IMS–MS) are increasingly being used to address challenges associated with the analysis of highly complex samples. In this work, we evaluate potential combination these techniques in form a comprehensive three-dimensional LC IMS separation system. As application, hydrophilic interaction (HILIC) reversed phase (RP-LC) IMS–high-resolution MS (HR-MS) was analyze range phenolic...
‘Wonderful’ pomegranate (Punica granatum L.) peel contains a wide range of phytochemicals including vitamins, dietary fibre, phenolic compounds, and antioxidant properties. Yet, it is often used as animal feed or discarded in landfills, which not the best eco-friendly way to utilize this phenolic-rich bioresource. Finding novel ways utilizing waste could prove more profitable eco-friendlier alternative that far beneficial economy. Adding blanching pre-treatment step at optimal conditions...
Ochratoxin A (OTA) is a nephrotoxic and carcinogenic mycotoxin. The toxin common contaminant of various foods feeds poses serious threat to the health both humans animals. number commercial hydrolases were screened for ability degrade OTA nontoxic compounds. crude lipase from Aspergillus niger (Amano A) proved substantially hydrolyze OTα phenylalanine, as confirmed by HPLC with fluorescence detection. enzyme was purified anion exchange chromatography homogeneity. Activity staining α-naphthyl...
The effect of oxygen on the levels glutathione, an important antioxidant, in must and wine was studied using a novel LC-MSMS method for analysis reduced oxidized glutathione. This study found that storage grape juice at high SO2 ascorbic acid −20 °C did not lead to decrease glutathione levels. varying South African white juices, which included reductive treatment (less than 0.3 mg/L dissolved O2 added), control (between 1.0 1.5 oxidative (3.5−4 mg/ L added, without SO2) resulting also...
Despite the significant importance of tannins in viticulture and enology, relatively little is known about detailed chemical composition these molecules. This due to challenges associated with accurate analytical determination highly structurally diverse proanthocyanidins which comprise tannins. In this contribution, we address limitation by demonstrating how online comprehensive two-dimensional liquid chromatography (LC × LC) coupled high resolution mass spectrometry (HR-MS) can be...
Hot water blanching at 80 °C for 3 min can be used as a novel pre-treatment step in pomegranate peel to preserve the integrity of phytochemical content within extracts by lowering or inactivating enzymes such polyphenol (PPO) oxidase and peroxidase (POD) that are responsible break-down phytochemicals peel. The aim this study was investigate effect hot on yield, bioactive compounds, antioxidants, enzyme inactivation, antibacterial activity ‘Wonderful’, ‘Acco’, ‘Herskawitz’ extracts. We...
Fusarium ear rot of maize, caused by verticillioides, is an important disease affecting maize production worldwide. Apart from reducing yield and grain quality, F. verticillioides produces fumonisins which have been associated with mycotoxicoses animals humans. Currently, no breeding lines are known resistance to in South Africa. The objective this study, therefore, was evaluate 24 genetically diverse inbred as potential sources fumonisin accumulation field trials at Potchefstroom Vaalharts...
Asiaticoside, a well-known ursane-type triterpene saponin widely used as chemical marker in quality control of commercial samples Centella asiatica, occurs South African material (12 from four provenances) at level 1 to 2% dry weight. Surprisingly, the compound was not detected three C. glabrata, only other species with well-recorded history medicinal use. A preliminary LC-MS survey further 21 leaf 16 revealed presence asiaticoside major constituent ten studied, while others had various...
The metabolite profiles of Sutherlandia frutescens populations may vary depending on their geographical location, affecting the quality plant-based pharmaceutical products generated from this species. This paper aims at using metabolic profiling through liquid chromatography mass spectrometry (LC–MS) to assess content seed pods medicinal plant S. growing in geographically different environments. Terpenoid (retention time: 7.5–9.0 min) and flavonoid 15.0–19.0 regions chromatograms were useful...
The mycotoxin, ochratoxin A (OTA), an important nephrotoxin, teratogen and carcinogen, is mainly produced as a secondary metabolite of Aspergillus Penicillium species. mycotoxin common contaminant various feedstuffs foodstuffs such grains, coffee wine. levels OTA have been established in 122 South African wines, representative variety wine cultivars from wine-producing regions the country. method analysis was based on Visconti et al. (1999): it consisted immunoaffinity clean up,...