Zeno Apostolides

• DSc
• University of Pretoria

Inhibition of pancreatic alpha-amylase and alpha-glucosidase is a common strategy to manage type 2 diabetes. This study focuses on the ability of compounds present in commercially available herbs and spices to inhibit pancreatic alpha-amylase and alpha-glucosidase. In silico molecular docking was performed to evaluate the binding affinity of the co...

Due to the unpredictable natural droughts that occur, causing tea farmers significant losses in tea estates, a two-day method for distinguishing between drought tolerant (DT) and drought susceptible (DS) Camellia sinensis cultivars was developed. This work was based on known cultivars developed at the Tea Research Institute in Kenya and the Tea Res...

Triterpenoids have been identified as potential novel lipid-lowering drugs for the treatment of hypertriglyceridemia. This study investigated the potential antilipogenic and/or antilipolytic effects of two triterpenoids (ARM-2 and RA-5) isolated from the stem bark of Protorhus longifolia (Benrh.) Engl. Employing a combination of in silico predictio...

Moringa is an important anti-methanogenic plant with a potential to develop as multipurpose feed additives. Previous studies identified two potent accessions (accession 07633 designated as A3 and accession collected from Pretoria designated as A11) with high methane (CH4) inhibition characteristics. Two metabolite ion features (MIFs) 4.44_609.1462...

The increasing incidence of hypercholesterolemia-related diseases even in the presence of the currently available cholesterol-lowering drugs indicates a need to discover new therapeutic drugs. This study aimed to investigate the hypocholesterolemic potential of two triterpenoids isolated from Protorhus longifolia stem bark. In silico techniques and...

Ethnopharmacological relevance: Tea (Camellia sinensis) has been consumed for centuries as traditional medicine for various diseases, including diabetes. The mechanism of action of many traditional medicines, including tea, often requires elucidation. Purple tea is a natural mutant of Camellia sinensis, grown in China and Kenya, and is rich in ant...

Plant phytochemicals are an important area of study in ruminant nutrition, primarily due to their antimethanogenic potentials. Plant extract yields, their bioactive compounds and antimethanogenic properties are largely dependent on the nature of the extractive solvents. This study evaluated the yields and phytochemical constituents of four plant ex...

The use of medicinal plants and their extracts has recently attracted the attention of many researchers as a methane (CH4) mitigation strategy. This study evaluated the relationship of agronomic traits of Moringa accessions with in vitro gas production measurements and feed digestibility from ruminants. Twelve Moringa accessions were grown at the R...

Introduction Several therapeutic targets have been identified for the management of type 2 diabetes (T2D), including the inhibition of α-amylase and α-glucosidase. The present study determined the ability of curcumin, 18α-glycyrrhetinic acid, quercetin and rosmarinic acid to inhibit α-amylase, α-glucosidase, and hepatic lipid accumulation. Methodo...

This study evaluated the relationship of secondary bioactive plant metabolite ion-features (MIFs) of Moringa oleifera accessions with antimethanogenesis to identify potential MIFs that were responsible for high and low methane inhibition from ruminants. Plant extracts from 12 Moringa accessions were evaluated at a 50 mg/kg DM feed for gas productio...

Tea (Camellia sinensis) has enthralled both consumers and researchers, due to its taste, aroma and its medicinal attributes. Tea consumers concern themselves with the quality of tea in particular, its taste and aroma based on which consumers are willing to pay premium prices for the best quality teas. The quality of tea is undeniably affected by va...

As the second most consumed non-alcoholic beverage, the tea plant (Camellia sinensis) has high economic value. Tea improvement efforts that largely target economic traits such as yield have traditionally relied on conventional breeding approaches. The tea plant’s perennial nature and its long generation time make conventional approaches time-consum...

Genomic selection in tea plant (Camellia sinensis) breeding has the potential to accelerate efficiency of choosing parents with desirable traits at the seedling stage. The study evaluated different genome‐enabled prediction models for black tea quality and drought tolerance traits in discovery and validation populations. The discovery population co...

Culinary herbs and spices are widely used as a traditional medicine in the treatment of diabetes and its complications, and there are several scientific studies in the literature supporting the use of these medicinal plants. However, there is often a lack of knowledge on the bioactive compounds of these herbs and spices and their mechanisms of acti...

Tea is the world’s most consumed beverage, next to water. This makes it an economically important crop. However, the genetic relationship between the cultivars at the Tea Research Foundation of Central Africa (TRFCA) have not been classified. This study assessed 56 tea accessions from the TRFCA. The 56 accessions were split into five groups, namely...

The understanding of black tea quality and percent relative water content (%RWC) traits in tea (Camellia sinensis) by a quantitative trait loci (QTL) approach can be useful in elucidation and identification of candidate genes underlying the QTL which has remained to be difficult. The objective of the study was to identify putative QTL controlling b...

The advancements in genotyping have opened new approaches for identification and precise mapping of quantitative trait loci (QTL) in plants, particularly by combining linkage and association mapping (AM) analysis. In this study, a combination of linkage and AM approach was used to precisely identify and authenticate putative QTLs associated with bl...

Root rot of citrus trees caused by Phytophthora nicotianae is responsible for severe economic losses in citriculture. Use of resistant rootstocks is an effective method of managing this problem, however, breeding and selection of new citrus rootstocks is a time-consuming undertaking. The objective was to develop a method for the rapid assessment of...

Tea (Camellia sinensis) contains polyphenols and caffeine which have been found to be of popular interest in tea quality. Tea production relies on well-distributed rainfall which influence tea quality. Phenotypic data for two segregating tea populations TRFK St 504 and TRFK St 524 were collected and used to identify the quantitative trait loci (QTL...

Ilex guayusa tea preparations are now commercially available as Runa tea. Little is known regarding the antioxidant and anti-inflammatory bioactivities of this tea. The I. guayusa teas had a total polyphenolic content between 54.39 and 67.23 mg GAE per g dry mass and peroxyl radical scavenging capacities between 1773.41 and 2019 μmol TE per g dry m...

Tea (Camellia sinensis) contain polyphenols and caffeine which have been found to be of popular interest in tea quality. Tea production relies on well distributed rainfall which influence tea quality. Phenotypic data for two segregating tea populations TRFK St 504 and TRFK St 524, were collected and used to identify the quantitative trait loci (QTL...

Despite potential links between pesticides and bee declines, toxicology information on honey bee larvae (Apis mellifera) is scarce and detoxification mechanisms in this development stage are virtually unknown. Larvae are exposed to natural and synthetic toxins present in pollen and nectar through consumption of brood food. Due to the characteristic...

Honey bees (Apis mellifera) are generalist pollinators that forage for nectar and pollen of a very large variety of plant species, exposing them to a diverse range of secondary metabolites produced as chemical defences against herbivory. Honey bees can tolerate high levels of many of these toxic compounds, including the alkaloid nicotine, in their...

Climate change is causing droughts affecting crop production on a global scale. Classical breeding and selection strategies for drought-tolerant cultivars will help prevent crop losses. Plant breeders, for all crops, need a simple and reliable method to identify drought-tolerant cultivars, but such a method is missing. Plant metabolism is often dis...

The principal pigments present in black tea, theaflavins (TF), have been indicated to be of potential clinical significance in various fields of research which has been hampered by the very low levels of TFs from black tea extractions, being the original method employed to acquire TFs. Forelle pear (44 µM TF/g dry weight/h) and Yacon leaf (65 µM TF...

Context Pelargonium sidoides DC (Geraniaceae) is an important medicinal plant indigenous to South Africa and Lesotho. Previous studies have shown that root extracts are rich in polyphenolic compounds with antibacterial, antiviral and immunomodulatory activities. Little is known regarding the anticancer properties of Pelargonium sidoides extracts. O...

Extracts prepared from the roots of Pelargonium sidoides (DC) are commercially available for the treatment of respiratory related conditions. Recently, a commercial radix mother tincture of this plant was shown to have both antioxidant and anticancer effects especially related to the G 0/G 1 block in the Jurkat E6.1 cell line (unpublished results)....

Insecticides are thought to be among the major factors contributing to current declines in bee populations. However, detoxification mechanisms in healthy, unstressed honey bees are poorly characterised. Alkaloids are naturally encountered in pollen and nectar, and we used nicotine as a model compound to identify the mechanisms involved in detoxific...

Polymyxins have previously been described to have activity against Mycobacterium tuberculosis (MTB), but further research was abandoned due to systemic toxicity concerns to achieve the required MIC. Colistin methanesulfonate (CMS), a polymyxin, is well tolerated when inhaled directly into the lungs, resulting in high local concentrations. We report...

Head-space volatiles of the edible pulp of the mobola plum (Parinari curatellifolia) were extracted using solid phase microextraction (SPME), and their identities determined by GC–FID and GC–MS systems. The SPME method extracted eleven major compounds accounting for 99.0% of the volatile constituents. The volatiles were ethyl butyrate, 28.7%; ethyl...

Moringa oleifera is becoming increasingly popular as an industrial crop due to its multitude of useful attributes as water purifier, nutritional supplement and biofuel feedstock. Given its tolerance to sub-optimal growing conditions, most of the current and anticipated cultivation areas are in medium to low rainfall areas. This study aimed to asses...

Pelargonium sidoides is a South African indigenous medicinal plant. The roots of the plant are used as a traditional herbal medicine by local people and it is also exported overseas where it is used to make medicine for the treatment of upper respiratory tract infections. There is no commercial cultivation of the plant and this has placed the natur...

This study was done to identify random amplified polymorphic DNA (RAPD) markers that may associate with seven important traits in tea. Sixty RAPD primers were first screened using 18 cultivars under each of the 7 traits, followed by confirmatory screening of 20 promising primers with 32 tea cultivars. Six RAPD primers generated a total of nine spec...

Volatile constituents of the edible pulp of Strychnos cocculoides (Monkey orange) were extracted using solid phase microextraction (SPME) and their identity established by GC–FID and GC–MS systems. Six compounds were extracted and identified: isobutyl acetate, 53.2%; 2-methylbutyl acetate, 12.8%; ethyl-2-methylbutyrate, 10.5%; 2, 6-ditetrabutyl-4-m...

The anatomical localization of caffeine within young Camellia sinensis leaves was investigated using immunohistochemical methods and confocal scanning laser microscopy. Preliminary fixation experiments were conducted with young C. sinensis leaves to determine which fixation procedure retained caffeine the best as determined by high-performance liqu...

Moringa oleifera is becoming increasingly popular as an industrial crop due to its multitude of useful attributes as water purifier, nutritional supplement and biofuel feedstock. Given its tolerance to sub-optimal growing conditions, most of the current and anticipated cultivation areas are in medium to low rainfall areas. This study aimed to asses...

Moringa oleifera Lam. is a fast growing, drought tolerant tree with numerous beneficial uses, such as for nutritious food, animal forage, green manure, water purification, traditional medicine and bio-fuel (Anwar et al., 2007). The developmental seed morphology and anatomy of Moringa has not been researched, especially with regards to the accumulat...

Computer disc in envelope on inside back cover. Master disk in Africana OVDISK 42 copy number 1536967. Thesis (DSc(Agric)) University of Pretoria, 1989.

The potential for mucuna bean protein isolate (MBPI) application as functional ingredient in foods is unknown. In this study nutritional quality and physicochemical properties of MBPI were investigated. Bean samples were processed for L-dopa extraction in distilled water adjusted to pH 3.2 at 60°C for 48hr. MBPI was extracted at pH 9.0 and isoelect...

The effects of moisture stress were evaluated in four Indigofera species (I. amorphoides, I. arrecta, I. coerulea and I. vicioides) using a pot experiment under glasshouse conditions. The aim was to examine the influence of moisture-deficit stress on physiological attributes and performance of the four Indigofera species. Based on plant available w...

Twenty-four shrubby Indigofera accessions from 7 species were evaluated in terms of their forage production, potential nutritive value and indospicine levels in the forage biomass over two growing seasons. Eighteen seedlings per plot were transplanted into field plots measuring 1.5 × 3 m in January 2003 at spacings of 50 cm between and within rows,...

The suitability of micellar electrokinetic chromatography for the simultaneous trace determination of several compounds (sulfamethoxazole, trimethoprim, sulfanilic acid, sulfanilamide, 3,4,5-trimethoxybenzoic acid and nonoxynol-9) was assessed. The mixture was separated within 14min at an applied voltage of 22kV by using 30mM phosphate electrolyte,...

Twenty-four shrubby Indigofera accessions from 7 species were evaluated in terms of their forage production, potential nutritive value and indospicine levels in the forage biomass over two growing seasons. Eighteen seedlings per plot were transplanted into fi eld plots measuring 1.5 × 3 m in January 2003 at spacings of 50 cm between and within rows...

Several animal models for the study of HIV/AIDS have been established and characterized and have been widely used to study the pathogenesis of HIV/AIDS as well as vaccine development. The purpose of this study was to review the literature and identify the animal models most frequently used for the evaluation of drugs, drug combinations, plant extra...

Knowledge of the existing genetic variation between various morphological and agronomic traits is vital for any collection, conservation and breeding programs. Forty-one Indigofera acces- sions from 8 different species were studied in a randomised block design with 3 replicates to characterise the accessions, using morphological and/or agronomic da...

Reliable and accurately measurable chemical parameters that can be used to estimate black tea quality are desirable in trade, research and breeding programmes. Using plain Kenyan black tea from 11 cultivars, which gave some significant differences in their plain black tea quality parameters, the individual theaflavins composition, total theaflavins...

Analytical method validation, determining the recovery rate from the equipment surface and the stability of a potential contaminant are important steps of a cleaning validation process. A rapid, sensitive and reproducible reversed-phase high-performance liquid chromatographic method was developed for the determination of pyrimethamine (PYR) and sul...

provides an update of the validation of moist heat sterilization. It brings together practical information one needs when validating an autoclave, from procure-ment through routine use. In Part I of this article, the sterility concept, sterilization principles, development of sterili-zation cycles, and the measurement of sterilization efficiency ar...

This article illustrate a qualification-validation strategy for moist heat sterilization and briefly discusses the sterility concept and common sterilization principles. In Part II, the authors discuss the qualification-validation procedure, including the installation, operational, and performance qualification phases, when requalification-revalida...

A parameter of black tea that correlates with quality is highly desired. Twenty good and 20 poor quality tea clones were selected from the breeding programme at the Tea Research Foundation (Central Africa) (TRF(CA)). The theaflavin (TF) composition of the black tea manufactured from each clone was analysed by capillary electrophoresis and correlate...

Most of the health benefits of black, green and oolong teas made from Camellia sinensis are attributed to their antioxidant content. Many plants and spices have been used to make infusions that are erroneously referred to as 'teas'. The term 'rich in antioxidants' is often used to describe such infusions, often without scientific support. We have u...

In this study a new capillary electrophoresis (CE) method was developed to quantify the four major theaflavins occurring in black tea. Where aqueous based CE methods showed poor selectivity and considerable band broadening, non-aqueous CE achieved baseline separation of the theaflavins within 10 min. The effects of the organic solvent composition a...

In this study a new capillary electrophoresis (CE) method was developed to quantify the four major theaflavins occurring in black tea. Where aqueous based CE methods showed poor selectivity and considerable band broadening, non-aqueous CE achieved baseline separation of the theaflavins within 10 min. The effects of the organic solvent composition a...

A parameter of fresh tea leaf that correlates with black tea quality is highly desired. Twenty good and 20 poor quality tea clones were selected from the breeding programme at the Tea Research Foundation (Central Africa) (TRF(CA)). The flavan-3-ol profile of fresh tea leaves was analysed by capillary electrophoresis while total theaflavin (TF) cont...

A parameter of fresh tea leaf that correlates with black tea quality is highly desired. Twenty good and 20 poor quality tea clones were selected from the breeding programme at the Tea Research Foundation (Central Africa) (TRF(CA)). The flavan-3-ol profile of fresh tea leaves was analysed by capillary electrophoresis while total theaflavin (TF) cont...

A new MEKC method has been developed to determine the amount of the phytoalexin, scoparone, in Citrus roots. The separation and analysis was achieved with a running buffer of 100 mM SDS, 25 mM phosphate and 12% (v/v) methanol pH 6.2. Separation was performed at 12 kV with 25°C and UV detection at 200 nm. A near complete recovery of scoparone was ob...

A micellar electrokinetic capillary chromatography (MEKC) method for the simultaneous analysis of five tea catechins, theanine, caffeine, gallic acid and ascorbic acid has been developed. The catechins are (-)-epicatechin, (+)-catechin, (-)-epigallocatechin, (-)-epicatechin gallate and (-)-epigallocatechin gallate. p-Nitrophenol serves as both refe...

Some epidemiological studies have associated tea drinking with several health benefits, while other such studies have been inconclusive. The liver enzyme, xanthine oxidase (XO) produces uric acid and reactive oxygen species (ROS) during the catabolism of purines. Excess of the former can lead to gout and of the latter to increased oxidative stress,...

Aqueous solutions of gallic acid, methyl gallate, catechins, theaflavins and tannic acid were tested for inhibition of the mutagenicity of PhIP in the Salmonella typhimurium TA98 assay with an S9 fraction from the liver of rats induced with alpha-naphthoflavone and phenobarbital. The IC50S were in the 80-250 microM range for the gallated catechins,...

Solutions of lyophilized preparations of standard black and green tea extracts were made and tested over a range of six concentrations as inhibitors of the mutagenicity caused by the fool mutagen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in the Salmonella typhimurium TA98 assay containing S9 fraction from rats induced with alpha-naphth...

Standard black and green tea extracts have been known to inhibit mutagenicity caused by PhIP, in the Salmonella typhimurium TA98 assay containing S9 fraction from the liver of rats induced with alpha-naphthoflavone and phenobarbital. Breeding and selection programs for high yielding tea clones have successfully increased yields in many tea producin...

Cropping trials were carried out with mushroom compost supplemented at casing and at spawning. Protein-rich organic substrates, some of which were formaldehyde- and/or heat-treated, were used as supplements. Mushroom production could be increased significantly, both by supplementation at spawning and supplementation at casing. Results were compared...

Die verdraagsaamheid van mieliesaailinge (Zea mays L. kv SSM2041) teenoor atrasien is in 'n glashuis ondersoek. Plante is in potte gekweek, in voedingsoplossings met tekorte aan sekere makro-elemente. Atrasien in die voedingsoplossings is periodiek bepaal met behulp van hoëdrukvloeistofchromatografie. Tekorte aan N, P, K, Ca en Mg, afsonderlik of i...

Summary In this study the gas chromatographic method of Poly-β-hydroxy butyric acid determination of Braunegg et al. (1978), was optimised for activated sludge samples. The poly-β-hydroxy butyric acid was extracted and quantified gravimetrically to confirm the accuracy of the gas chromatographic method. The authenticity of the extracted material w...

Analytical method validation, determining the recovery rate from the equipment surface and the stability of a potential contaminant are important steps of a cleaning validation process. A flowchart presenting the place and importance of these steps in a cleaning validation strategy is presented. A rapid, sensitive and reproducible reversed-phase hi...