Department of Pharmaceutical Sciences - Research Articles

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The in vitro antibiofilm activity of selected culinary herbs and medicinal plants against listeria monocytogenes.
(Oxford University Press (OUP), 2009-09-18) Sandasi, M.; Leonard, C.M.; Viljoen, A.M.
Aims: The antibiofilm activity of extracts obtained from selected herbs, spices, beverages and commercially important medicinal plants was investigated on Listeria monocytogenes. Methods and Results: The growth and development of the biofilm was assessed using the crystal violet (CV) assay. The respiratory activity was assessed using the 2, 3-bis [2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT) reduction assay. The majority of extracts tested prevented cell adhesion to the polyvinyl chloride (PVC) surface. Seven of the 15 extracts reduced biofilm adhesion of both the clinical and the type strains by at least 50%. In contrast, inhibition of a preformed biofilm was more difficult to achieve, with only three extracts (Rosmarinus officinalis, Mentha piperita and Melaleuca alternifolia) inhibiting the growth of both strains by at least 50%. Conclusions: Although most extracts were able to reduce initial cell attachment, inhibition of growth in a preformed biofilm was more difficult to achieve. Significance and Impact of the Study: The ability to reduce biofilm biomass as shown by several plant extracts warrants further investigation to explore the use of natural products in antibiofilm adhesion.
Bioactivity of selected essential oils and some components on listeria monocytogenes biofilms.
(Elsevier B.V., 2010-07-03) Leonard, C.M.; Virijevic, S.; Regnier, T.; Combrinck, S.
Listeria monocytogenes is a Gram-positive bacterium, able to survive and grow in water, soil, agricultural products, various foods and the food processing environment. The ubiquitous nature of the organism, coupled with its ability to colonise food-processing surfaces by forming biofilms, causes it to be of a major concern to the industry. Increased foodborne pathogen resistance and negative consumer perceptions regarding the use of synthetic bacteriocides, has resulted in natural antimicrobials being sourced from the plant kingdom. The listerial antibiofilm activities of Syzygium aromaticum (clove), Mentha spicata (spearmint), Lippia rehmannii and Cymbopogon citratus (lemongrass) essential oils and their major components were evaluated using the crystal violet assay and confocal scanning laser microscopy. Listerial biofilms treated with S. aromaticum or M. spicata essential oils, or the pure compounds nerol and citral, exhibited a similar biofilm biomass to the positive control. However, the essential oils of lemongrass, L. rehmannii, eugenol and R-carvone caused biofilm enhancement, rather than inhibition. L. rehmannii and lemongrass essential oils did not display any antibiofilm properties. Results obtained were confirmed by microscopic observations indicating either a reduction (inhibition) or an increase (enhancement) in biofilm biomass when exposed to the essential oils or pure compounds. The present study revealed that M. spicata and S. aromaticum essential oils as well as pure citral and nerol are good candidates for further development of ecofriendly disinfectants.
Activity of South African medicinal plants against Listeria monocytogenes biofilms, and isolation of active compounds from Acacia karroo.
(Elsevier B.V., 2011-09-04) Nyila, M.A.; Leonard, C.M.; Hussein, A.A.; Lall, N.
In South Africa, the antimicrobial activity of many indigenous plants has been investigated. In general, studies have focused on planktonic bacteria, with less attention given to bacterial biofilms. Many organisms, however, including the opportunistic pathogen Listeria monocytogenes occur more frequently as biofilms. The aim of this study was to identify and select plants that exhibit the best antilisterial activity, isolate the bioactive compounds and determine their effect on the architecture of listerial biofilms. The ethyl acetate and chloroform extracts of thirteen plants were investigated for antilisterial activity. The ethyl acetate extract of Acacia karroo and Plectranthus ecklonii showed the best antilisterial activity, exhibiting a minimum inhibitory concentration (MIC) of 3.1 mg/ml and 0.5 mg/ml, respectively. These were further selected for the identification of bioactive compounds. Column chromatographic purification of the ethyl acetate extracts of the leaves of A. karroo led to the isolation of three known pure compounds, namely epicatechin (1), β-sitosterol (2) and epigallocatechin (3). Confocal scanning laser microscopy (CSLM) showed that the biomass of the listerial biofilm was reduced when the isolated compounds were added. The aggregation of cells that were exposed to β-sitosterol and epigallocatechin was reduced from 25 μm as observed in untreated cells to b10 μm in length.
Comparison of fatty acid methyl esters of palm and palmist oils determined by GCxGC–ToF–MS and GC–MS/FID.
(Elsevier B.V., 2017-06-30) Kamatou, G.P.P.; Viljoen, Alvaro M.
Palm oil obtained from the mesocarp of Elaeis guineensis contains polyunsaturated fatty acids which are essential for normal human growth and development. Five samples of palm oil obtained from Cameroon (n=3), Nigeria (n = 1) and Ghana (n = 1) and two palmist oil samples (commercially available and raw oils) were obtained from Cameroon. Comprehensive gas chromatography coupled to time-of-flight mass spectrometry (GCxGC– ToF–MS) and gas chromatography coupled to mass spectrometry and/or a flame ionization detector (GC–MS/ FID) were used to determine the fatty acids, as their methyl esters (FAMEs) in these two products. The major compounds as determined with GCxGC–ToF–MS and GC–MS/FID in palm oil were hexadecanoic acid methyl ester (27.4–44.1%), 9-octadecenoic acid methyl ester (33.7–45.2%), 9–12-octadecadienoic acid methyl ester (8.5–13.4%) and stearic acid methyl ester (2.7–13.7%). Some of the minor FAMEs were region specific. The palmist oil showed little variation (both with one- and two-dimensional GC) with dodecanoic acid methyl ester (30.4–40.1%), tetradecanoic acid methyl ester (15.1–20.6%), (9-octadecenoic acid methyl (13.0–17.6%) and hexadecanoic acid methyl ester (11.2–18.4%), being the most prominent. Identified FAMEs such as (Z,Z,Z)- 9,12,15-octadecadienoic acid methyl ester; tetradecanoic acid, 12-methyl, methyl ester were used to differentiate between the two palmist oils when using two dimensional GC. In general fewer FAMEs could be detected by GC–MS/FID (usually less than 10), while this number doubled when the oils were separated using two dimensional GC.
Synergistic and antagonistic interactions of essential oils on the biological activities of the solvent extracts from three salvia species.
(SAGE Publications, 2008-04-29) Kamatoua, Guy P. P.; Van Zyl, Robyn L.; Davids, Hajierah; Van Vuuren, Sandy F.; Viljoen, Alvaro M.
The solvent extracts of aromatic plants contain both volatile (e.g. essential oils) and non-volatile compounds. The biological activities (antibacterial, antioxidant, anti-plasmodial and anticancer) of the solvent extracts of three South African Salvia species (Salvia Africana-caerulea, S. Africana-lutea and S. lanceolata) were evaluated in the presence and absence of the essential oils. The solvent extract of S. Africana-caerulea free of essential oil exhibited the best activity against Gram-positive bacteria (MIC value: 0.4 mg/mL), while the solvent extract containing essential oil of S. lanceolata was the most active against Gram-negative bacteria (MIC value: 2.0 mg/mL). No significant difference was obtained in the anti-plasmodial activity of the solvent extract with or without the essential oils of S. Africana-caerulea and S. lanceolata, while the activity of the solvent extract without essential oil was significantly higher than that of the solvent extract containing the essential oil in S. Africana lutea (p < 0.05). The toxicity profile of all three species was significantly higher (p < 0.05) with the solvent extracts containing essential oils than when assessed in the absence of the essential oil.
Linalool – A review of a biologically active compound of commercial importance.
(SAGE Publications, 2008-05-31) Kamatou, Guy P.P.; Viljoen, Alvaro M.
Since the earliest times fragrant materials have been used in rituals. Today, a lucrative industry has developed to produce and deliver fragrances and aromatic chemicals with various applications in modern society. Linalool, a much sought after compound in the flavor and fragrance industry is a monoterpene alcohol which occurs naturally in many aromatic plants. Linalool and linalool-rich essential oils are known to exhibit various biological activities such as antimicrobial, anti-inflammatory, anticancer, antioxidant properties and several in vivo studies have confirmed various effects of linalool on the central nervous system. The applications of linalool are not confined to simply adding or enhancing a specific scent to domestic products such as soaps, detergents and shampoos. Linalool also plays an import role in nature as a key compound in the complex pollination biology of various plant species to ensure reproduction and survival. Linalool is also a key compound for the industrial production of a variety of fragrance chemicals such as geraniol, nerol, citral and its derivatives, as well as a lead compound in the synthesis of vitamins A and E. The repellent properties of linalool on various crop-destroying insects has been well documented accentuating the application of this molecule in eco-friendly pest management. This review aims to highlight the various biological properties of linalool and to emphasize the value of linalool and linalool-rich essential oils in phytotherapy.
Hyperspectral imaging as a rapid quality control method for herbal tea blends.
(MDPI, 2017-03-01) Djokam, Majolie; SandasI, Maxleene; Chen, Weiyang; Viljoen, Alvaro; Vermaak, Ilze
In South Africa, indigenous herbal teas are enjoyed due to their distinct taste and aroma. The acclaimed health benefits of herbal teas include the management of chronic diseases such as hypertension and diabetes. Quality control of herbal teas has become important due to the availability of different brands of varying quality and the production of tea blends. The potential of hyperspectral imaging as a rapid quality control method for herbal tea blends from rooibos (Aspalathus linearis), honeybush (Cyclopia intermedia), buchu (Agathosma Betulina) and cancerbush (Sutherlandia frutescens) was investigated. Hyperspectral images of raw materials and intact tea bags were acquired using a sisuChema shortwave infrared (SWIR) hyperspectral pushbroom imaging system (920–2514 nm). Principal component analysis (PCA) plots showed clear discrimination between raw materials. Partial least squares discriminant analysis (PLS-DA) models correctly predicted the raw material constituents of each blend and accurately determined the relative proportions. The results were corroborated independently using ultra-high performance liquid chromatography coupled to mass spectrometry (UHPLC-MS). This study demonstrated the application of hyperspectral imaging coupled with chemometric modelling as a reliable, rapid and non-destructive quality control method for authenticating herbal tea blends and to determine relative proportions in a tea bag.
The topical efficacy and safety of Citrullus lanatus seed oil: A short-term clinical assessment.
(Elsevier, 2017-06-30) Komane, B.; Vermaak, I.; Kamatou, G.; Summers, B.; Viljoen, A.
The oil obtained from the seeds of Citrullus lanatus (Thunb.) Matsum. & Nakai (Kalahari melon) is highly sought after in the cosmetic industry as a prized ingredient to maintain healthy skin. Seed oils contain a range of fatty acids that may be beneficial upon topical application to the skin. The quantification of the fatty acids was done using two dimensional gas chromatography coupled to mass spectrometry (GC × GC–MS). The safety (irritancy potential test) and efficacy (transepidermal water loss (TEWL), hydration and occlusivity tests) of topically applied Kalahari melon seed oil on healthy Caucasian adult female volunteers (n = 20) was determined. Skin irritation and dryness were determined by visual scoring using a 2× magnifying lamp while Chromameter®, Aquaflux® and Corneometer® instruments were used to quantify the irritancy level, TEWL and hydrating properties of Kalahari melon oil, respectively. The occlusive effect of the oil was assessed using Aquaflux® and Corneometer® instruments. Four major fatty acids, linoleic acid (51.4%), oleic acid (36.7%), stearic acid (6.3%) and palmitic acid (5.6%), were quantified using comprehensive GC × GC–MS analysis. Kalahari melon seed oil was non-irritant to the skin when topically applied (observed at 24, 48, 72 and 96 h). Aquaflux® and Corneometer® results showed that the application of Kalahari melon seed oil resulted in reduced TEWL and increased moisture retention. The non-irritant, hydrating and moisturising effects of Kalahari melon seed oil observed in this study justifies its incorporation into cosmetic products.
Hyperspectral imaging and chemometric modeling of echinacea — a novel approach in the quality control of herbal medicines.
(MDPI, 2014-08-17) Sandasi, Maxleene; Vermaak, IIze; Chen, Weiyang; Viljoen, Alvaro M.
Echinacea species are popularly included in various formulations to treat upper respiratory tract infections. These products are of commercial importance, with a collective sales figure of $132 million in 2009. Due to their close taxonomic alliance it is difficult to distinguish between the three Echinacea species and incidences of incorrectly labeled commercial products have been reported. The potential of hyperspectral imaging as a rapid quality control method for raw material and products containing Echinacea species was investigated. Hyperspectral images of root and leaf material of authentic Echinacea species (E. angustifolia, E. pallida and E. purpurea) were acquired using a sisuChema shortwave infrared (SWIR) hyperspectral pushbroom imaging system with a spectral range of 920–2514 nm. Principal component analysis (PCA) plots showed a clear distinction between the root and leaf samples of the three Echinacea species and further differentiated the roots of different species. A classification model with a high coefficient of determination was constructed to predict the identity of the species included in commercial products. The majority of products (12 out of 20) were convincingly predicted as containing E. purpurea, E. angustifolia or both. The use of ultra performance liquid chromatography-mass spectrometry (UPLC-MS) in the differentiation of the species presented a challenge due to chemical similarities between the solvent extracts. The results show that hyperspectral imaging is an objective and non-destructive quality control method for authenticating raw material.
The application of vibrational spectroscopy techniques in the qualitative assessment of material traded as ginseng.
(MDPI, 2016-04-01) Sandasi, Maxleene; Vermaak, Ilze; Chen, Weiyang; Viljoen, Alvaro
The name “ginseng” is collectively used to describe several plant species, including Panax ginseng (Asian/Oriental ginseng), P. quinquefolius (American ginseng), P. pseudoginseng (Pseudoginseng) and Eleutherococcus senticosus (Siberian ginseng), each with different applications in traditional medicine practices. The use of a generic name may lead to the interchangeable use or substitution of raw materials which poses quality control challenges. Quality control methods such as vibrational spectroscopy-based techniques are here proposed as fast, non-destructive methods for the distinction of four ginseng species and the identification of raw materials in commercial ginseng products. Certified ginseng reference material and commercial products were analysed using hyperspectral imaging (HSI), mid-infrared (MIR) and near-infrared (NIR) spectroscopy. Principal component analysis (PCA) and (orthogonal) partial least squares discriminant analysis models (OPLS-DA) were developed using multivariate analysis software. UHPLC-MS was used to analyse methanol extracts of the reference raw materials and commercial products. The holistic analysis of ginseng raw materials revealed distinct chemical differences using HSI, MIR and NIR. For all methods, Eleutherococcus senticosus displayed the greatest variation from the three Panax species that displayed closer chemical similarity. Good discrimination models with high R2X and Q2 cum vales were developed. These models predicted that the majority of products contained either /P. ginseng or P. quinquefolius. Vibrational spectroscopy and HSI techniques in tandem with multivariate data analysis tools provide useful alternative methods in the authentication of ginseng raw materials and commercial products in a fast, easy, cost-effective and non-destructive manner.
Beauty in Baobab: a pilot study of the safety and efficacy of Adansonia digitata seed oil.
(Elsevier, 2016-07-14) Komane, Baatile M.; Vermaak, Ilze; Kamatou, Guy P.P.; Summers, Beverley; Viljoen, Alvaro M.
Recently there has been a renewed impetus in the search for novel ingredients to be used in the cosmetic industry and Baobab (Adansonia digitata L., Malvaceae) seed oil has received high interest. In this study, a commercial Baobab seed oil sample was characterised (fatty acid content) using GCxGC-ToF-MS and a pilot study on the safety and efficacy ofthe seed oil was performed. The safety and efficacy of Baobab seed oil after topical application was determined using healthy adult female caucasian participants (n = 20). A 2× magnifying lamp was used for visual analysis, while for monitoring and evaluation of the irritancy level, transepidermal water loss (TEWL) and hydration level of the skin, Chromameter®, Aquaflux® and Corneometer® instruments, respectively, were used. In addition, Aquaflux® and Corneometer® instruments were used to assess occlusive effects. Thirteen methyl esters were identified using GCxGC-ToF-MS. The major fatty acids included 36.0% linoleic acid, 25.1% oleic acid and 28.8% palmitic acid with 10.1% constituting trace fatty acids. The irritancy of sodium lauryl sulphate (SLS) in the patch test differed significantly compared to both de-ionised water (p < 0.001) and Baobab seed oil (p < 0.001) but the difference between the irritancy of Baobab seed oil and de-ionised water was not significant (p = 0.850). The moisture efficacy test indicated a reduced TEWL (p = 0.048) and an improved capacitance moisture retention (p < 0.001) for all the test products (Baobab oil, liquid paraffin, Vaseline® intensive care lotion and Vaseline®). The occlusivity wipe-off test indicated an increased moisture hydration (p < 0.001) and decreased TEWL particularly when Baobab oil was applied. Baobab possesses hydrating, moisturising and occlusive properties when topically applied to the skin. Baobab seed oil could be a valuable functional ingredient for cosmeceutical applications.
HPTLC fingerprinting of croton gratissimus leaf extract with preparative HPLC-MS-isolated marker compounds.
(Elsevier, 2017-10-14) Pudumo, J.; Chaudhary, S.K.; Chen, W.; Viljoen, A.; Vermaak, I.; Veale, C.G.L.
The leaves, root and bark of the aromatic African indigenous plant, Croton gratissimus Burch. (Euphorbiaceae), are widely used in traditional medicine to treat coughs, chest complaints, rheumatism, abdominal disorders and fever among others. In Afrikaans it is referred to as “Koorsbessie” which alludes to its traditional use as a pyrogenic. The chemical composition of plants is very complex and analysis and quality control can be very challenging due to natural variability. In addition, very few reference standards from plants, especially from Africa, are commercially available. Due to its visual nature and the holistic fingerprint produced, high performance thin layer chromatography (HPTLC) is often recommended for the quality control of plant material. The aim of this study was to develop an HPTLC fingerprint and isolate marker compounds for inclusion on HPTLC plates to enable quality control. Croton gratissimus leaf samples were collected from various parts of South Africa and extraction was optimised. HPTLC fingerprints were developed and optimised and images were captured before and after derivatisation under UV (254 nm, and 366 nm) and white light. Preparative high performance liquid chromatography hyphenated to mass spectrometry (HPLC-MS) was used to isolate marker compounds. Method development and optimisation determined the following: most efficient extraction solvent = methanol:water (8:2 v/v); mobile phase = ethylacetate:acetic acid:formic acid:water (100:11:11:27 v/v/v/v); and derivatising agent = natural product reagent. UPLC-MS analysis and 1D NMR spectroscopy were used to characterise and identify compound 1 as isoorientin and compound 2 as kaempferol-3-β-D-(6″-O-trans-p-coumaroyl) glucopyranoside, which correlated well with published spectral data. The final HPTLC fingerprint with biomarkers included showed good separation for profiling purposes and well-defined bands. The biomarkers at retention factor (Rf) 0.30 and Rf 0.69 for isoorientin and kaempferol-3-β-D-(6″-O-trans-p-coumaroyl) glucopyranoside, respectively, were present in all samples but varied quantitatively. The HPTLC method developed provided a good fingerprint for species authentication. Preparative HPLC-MS played a major role in successfully isolating marker compounds to be used for the quality control of C.gratissimus.
The role of the South African Journal of Botany as a vehicle to promote medicinal plant research– A bibliometric appraisal.
(Elsevier, 2018-07-16) Viljoen, Alvaro; Sandasi, Maxleene; Vermaak, Ilze
South Africa's unique flora and extensive use of African traditional medicines has created a unique research opportunity on medicinal plants for local and international scientists. In this paper, submitted to a special issue of South African Journal of Botany(SAJB) dedicated to “sub-Saharan Ethnobotany”, we aim to explore the research landscape on medicinal plant research as published in SAJB. A bibliometric assessment (1982–2017) showed that medicinal plant research represents 24% of the published volume in SAJB and that contributions on this topic are increasing exponentially. Although most papers are broad-basedinvitro screening studies, the range of topics covered is impressive. Antimicrobial (41%) and anti-oxidant (21%) studies dominate the research space with fewer studies focusing on diseases highly relevant to the African continent, e.g. malaria (3%) and tuberculosis (2%). Although the SAJB has contributed greatly to disseminating knowledge on important species (e.g. Aspalathus and Cyclopia) several taxa of potential economic relevance remain poorly investigated (e.g. Adansonia, Bulbine etc.). The citation footprint and authorship networks which have been established attest the pivotal role the SAJB has played to build research capacity and create awareness in this important field of research.
Phytochemical profiling and quality control of terminalia sericea burch. ex dc. using hptlc metabolomics.
(MDPI, 2021-01-05) Mulaudzi, Nduvho; Anokwuru, Chinedu P.; Tankeu, Sidonie Y.; Combrinck, Sandra; Chen, Weiyang; Vermaak, Ilze; Viljoen, Alvaro M.
Terminalia sericea is used throughout Africa for the treatment of a variety of conditions and has been identified as a potential commercial plant. The study was aimed at establishing a high-performance thin layer chromatography (HPTLC) chemical fingerprint for T. sericea root bark as a reference for quality control and exploring chemical variation within the species using HPTLC metabo3lomics. Forty-two root bark samples were collected from ten populations in South Africa and extracted with dichloromethane: methanol (1:1). An HPTLC method was optimized to resolve the major compounds from other sample components. Dichloromethane: ethyl acetate: methanol: formic acid (90:10:30:1) was used as the developing solvent and the plates were visualized using 10% sulfuric acid in methanol as derivatizing agent. The concentrations of three major bioactive compounds, sericic acid, sericoside and resveratrol-3-O-β-rutinoside, in the extracts were determined using a validated ultra-performance liquid chromatography-photodiode array (UPLC-PDA) detection method. The rTLC software (written in the R-programming language) was used to select the most informative retardation factor (Rf) ranges from the images of the analysed sample extracts. Further chemometric models, including principal component analysis (PCA) and hierarchical cluster analysis (HCA), were constructed using the web-based high throughput metabolomic software. The rTLC chemometric models were compared with the models previously obtained from ultra performance liquid chromatography coupled with mass spectrometry (UPLC-MS). A characteristic fingerprint containing clear bands for the three bioactive compounds was established. All three bioactive compounds were present in all the samples, although their corresponding band intensities varied. The intensities correlated with the UPLC-PDA results, in that samples containing a high concentration of a particular compound, displayed a more intense band. Chemometric analysis using HCA revealed two chemotypes, and the subsequent construction of a loadings plot indicated that sericic acid and sericoside were responsible for the chemotypic variation; with sericoside concentrated in Chemotype 1, while sericic acid was more abundant in Chemotype 2. A characteristic chemical fingerprint with clearly distinguishable features was established for T. sericea root bark that can be used for species authentication, and to select samples with high concentrations of a particular marker compound(s). Different chemotypes, potentially differing in their therapeutic potency towards a particular target, could be distinguished. The models revealed the three analytes as biomarkers, corresponding to results reported for UPLC-MS profiling and thereby indicating that HPTLC is a suitable technique for the quality control of T. sericea root bark.
A quality control perspective on devil’s claw, harpagophytum procumbens and H. zeyheri: Phytochemical analysis and DNA barcoding.
(Elsevier, 2021-09-23) Pretorius, E.; Mncwangi, N.P.; Kabongo, R.M.; Chen, W.; Vermaak, I.; Van der Bank, M.; Viljoen, A.M.
Devil’s claw is a popular natural anti-inflammatory phytomedicine. The preparation of Devil’s claw products is complicated by the similarity between the morphotypes of Harpagophytum procumbens and H. zeyheri. This study investigated the potential of a validated ultra-high performance liquid chromatography coupled to mass spectrometry (UHPLC-MS) method to investigate the harpagoside content of methanol extracts of the secondary tubers of both species. In addition, DNA barcoding was used to determine the identity of the Harpagophytum species included in commercial Devil’s claw products. Herbal reference material of H. procumbens and H. zeyheri, originally harvested in southern Africa, was morphologically authenticated and commercial products containing Harpagophytum were purchased on the internet using the search terms “Harpagophytum” or “Devil’s claw.” High-performance thin-layer chromatography (HPTLC) and UHPLC-MS was used for the qualitative and quantitative determination of harpagoside content in commercial products. The UHPLC-MS method developed had a limit of detection (LOD) of 0.165 mg/mL and a limit of quantification (LOQ) of 0.499 mg/mL. Quantitative UHPLC-MS analysis revealed high variability in the harpagoside content for both species; H. procumbens (0.17-4.37%) and H. zeyheri (0.00-3.07%). Only 41% of H. procumbens and 17% of H. zeyheri raw materials contained harpagoside. Using HPTLC, 90% of the commercial products tested were determined to contain harpagoside. The results were congruent with the UHPLC-MS analysis where the harpagoside content was out of specification for 10% of analyzed commercial products. The harpagoside content in commercial products varied from not detected to 3.50%. PCR amplification followed by comparative sequencing analysis of trnL-F, and ycf1 plastid gene amplicons indicated specific sites in trnL-F at positions 118 and 146 and at position 538 in ycf1 amplicons suitable to distinguish the two Harpagophytum species. These sites were used to barcode the herbal products and Character-based Barcode Recognition Obtained with Nucleotide eXposes (BRONX) analyses verified the taxonomic identity of the Harpagophytum in the samples. The results revealed that 76% (16/21) of the commercial products tested were incorrectly labelled as H. procumbens and, instead, contained H. zeyheri. Our study suggests that DNA barcoding in combination with the UHPLC-MS and HPTLC could significantly support herbal product authentication. This study contributed knowledge and methods that can be implemented to enhance the quality of commercial Devil’s claw products.
Exploring the wound healing potential of Lobostemon fruticosus using in vitro and in vivo bioassays.
(Elsevier, 2024-07-25) Kgosana, Mashilo R.; Sandasi, Maxleene; Ncube, Efficient; Vermaak, Ilze; Gouws, Chrisna; Viljoen, Alvaro M.
Ethnopharmacological relevance: Lobostemon fruticosus (L.) H.Buek is a perennial and woody shrub of the Boraginaceae family, found in the Cape region of South Africa. The leaves and twigs are used to treat dermatological conditions such as wounds, burns, ringworm, erysipelas and eczema. Anti-inflammatory, antibacterial, antiviral and anti-proliferative activities of L. fruticosus have been reported. However, there is a void in research which reports on the wound healing properties of this plant. Aim of the study: Aligned with the traditional use of L. fruticosus, our study aimed to use in vitro and in vivo bioassays to confirm the wound healing potential of the plant. Materials and methods: An aqueous methanol extract (80% v/v) of L. fruticosus was prepared using a sample collected from the Western Cape Province of South Africa and chromatographically profiled by ultra performance liquid chromatography coupled to mass spectrometry (UPLC-MS). The 3-(4,5-dimethylthiazol-2- yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxicity assay was performed to determine the non-toxic concentrations of the extract for subsequent use in the in vitro scratch assay. Both the human keratinocyte (HaCaT) and fibroblast (BJ-5ta) cell lines were employed in the in vitro scratch assay. The in vivo caudal fin amputation assay was used to assess the wound healing potential of L. fruticosus, by monitoring fin regeneration in zebrafish larvae treated with the plant extract at various concentrations. Results: Six major compounds were tentatively identified in the L. fruticosus extract namely; globoidnan A, globoidnan B, rutin, rabdosiin, sagerinic acid and rosmarinic acid. The potentially toxic pyrrolizidine alkaloids were also identified and quantitatively confirmed to be present at a low concentration of 119.58 ppm (m/m). Treatment of HaCaT and BJ-5ta cells with the plant extract in the scratch assay resulted in an increase in cell migration, which translates to accelerated wound closure. After 24 hr treatment with 100 μg/mL of extract, wound closure was recorded to be 91.1 ± 5.7% and 94.1 ± 1.3% for the HaCaT and BJ-5ta cells, respectively, while the untreated (medium) controls showed 72.3 ± 3.3% and 73.0 ± 4.3% for the two cell lines, respectively. Complete wound closure was observed between 24 and 36 hr, while the untreated control group did not achieve 100% wound closure by the end of the observation period (48 hr). In vivo, the crude extract at 100 μg/mL accelerated zebrafish caudal fin regeneration achieving 100.5 ± 3.8% regeneration compared to 68.3 ± 6.6% in the untreated control at two days post amputation. Conclusions: The study affirms the wound healing properties, as well as low toxicity of L. fruticosus using both in vitro and in vivo assays, which supports the traditional medicinal use. Other in vitro assays that target different mechanisms involved in wound healing should be investigated to support the current findings.
Globalization and pharmacy: A view from the developing world.
(SAGE Publications, 2002-05-01) Matowe, Lloyd; Katerere, David R.
A recent article in the British Medical Journal1 on globalization and health stirred quite a debate among readers. In the article, the author argues that globalization is beneficial to health. To pharmacists, an obvious offshoot from this debate is the relationship between globalization and the practice of pharmacy worldwide. In this opinion, we argue that globalization may be more harmful than beneficial to pharmacy, particularly in the less developed countries.
A desktop review of evaluation of implementation of national medicines policies in SADC countries.
(Elsevier, 2023-11-07) Modiba, William K.; Katerere, David R.; Mncwangi, Nontobeko P.
A national medicine policy (NMP), formerly referred to as a national drug policy (NDP) is a document that serves as a political commitment and guide for action by the government to provide safe, efficacious, quality assured, available, affordable and rationally used medicines. This is the first study to review the implemented components of the NMPs of the 16 South African Development Community (SADC) countries over the past ten years (2011–2021). Information published between 2011 and 2021 of each country such as pharmaceutical profiles, official government documents, WHO/HAI/World Bank datasets and research studies on the implemented components were appraised. Significant progress has been made by 16 SADC countries over the period 2011–2021 in implementing the NMP. The most commonly implemented components included the concept of essential medicines, pricing, and regulation. Though traditional and herbal medicines component is yet to be implemented by the majority. The pharmacist patient ratio of 1:2300 was below the target for all countries, prompting the need to strengthen the pharmacy personnel in the healthcare systems. Medicine pricing, affordability, and availability studies are necessary to develop equitable pricing policies that will improve the accessibility of medicines in all countries and the SADC region. With the exception of the Republic of Tanzania, SADC countries need to urgently revise their NMPs, thus adopting progressive processes such as incorporating Health Technology Assessment (HTA) in the NMP. All SADC countries require a strong, internationalistic evaluation culture built-in their policy formulation. As the first study to investigate the implemented NMPs in the SADC region, it could serve as a springboard for the countries to address their common pharmaceutical challenges thus improving their readiness for universal health coverage (UHC). Future in-depth cross-country studies in the SADC region are necessary to comprehensively evaluate the implemented components of NMPs.
Evaluation of the wound healing properties of South African medicinal plants using zebrafish and in vitro bioassays.
(Elsevier, 2021-11-22) Mhlongo, Fikile; Cordero-Maldonado, Maria Lorena; Crawford, Alexander D.; Katerere, David; Sandasi, Maxleene; Hattingh, Annah C.; Koekemoer, Trevor C.; Van der Venter, Maryna; Viljoen, Alvaro M.
Ethnopharmacological relevance: In South Africa, medicinal plants have a history of traditional use, with many species used for treating wounds. The scientific basis of such uses remains largely unexplored. Aim of the study: To screen South African plants used ethnomedicinally for wound healing based on their proangiogenic and wound healing activity, using transgenic zebrafish larvae and cell culture assays. Materials and methods: South African medicinal plants used for wound healing were chosen according to literature. Dried plant material was extracted using six solvents of varying polarities. Pro-angiogenesis was assessed in vivo by observing morphological changes in sub-intestinal vessels after crude extract treatment of transgenic zebrafish larvae with vasculature-specific expression of a green fluorescent protein. Subsequently, the in vitro anti-inflammatory, fibroblast proliferation and collagen production effects of the plant extracts that were active in the zebrafish angiogenesis assay were investigated using murine macrophage (RAW 264.7) and human fibroblast (MRHF) cell lines. Results: Fourteen plants were extracted using six different solvents to yield 84 extracts and the non-toxic (n=72) were initially screened for pro-angiogenic activity in the zebrafish assay. Of these plant species, extracts of Lobostemon fruticosus, Scabiosa columbaria and Cotyledon orbiculata exhibited good activity in a concentration dependent manner. All active extracts showed negligible in vitro toxicity using the MTT assay. Lobostemon fruticosus and Scabiosa columbaria extracts showed noteworthy anti-inflammatory activity in RAW 264.7 macrophages. The acetone extract of Lobostemon fruticosus stimulated the most collagen production at 122% above control values using the MRHF cell line, while all four of the selected extracts significantly stimulated cellular proliferation in vitro in the MRHF cell line. Conclusions: The screening of the selected plant species provided valuable preliminary information validating the use of some of the plants in traditional medicine used for wound healing in South Africa. This study is the first to discover through an evidence-based pharmacology approach the wound healing properties of such plant species using the zebrafish as an in vivo model.
Analysis of aflatoxin biomarkers in the hair of experimental animals.
(MDPI, 2021-07-20) Mupunga, Innocent; Janse van Rensburg, Ilse; Luthuli, Nokuthula; Abafe, Ovokeroye A.; Shai, Leshweni J.; Katerere, David R.
Analysis of body fluids and tissues of aflatoxin exposed individuals for the presence of aflatoxins and aflatoxin metabolites has emerged as a reliable indicator of exposure and metabolism of aflatoxins. However, current aflatoxin biomarkers are not appropriate for investigating the long-term effects of aflatoxin exposure. In this explorative study, we investigated the analysis of hair as a complementary or alternative matrix for the assessment of biomarkers of long-term aflatoxin exposure. Three groups of guinea pigs were orally dosed with 5 ugkg−1bw−1, 50 ugkg−1bw−1, and 100 ugkg−1bw−1 of AFB1. Urine and hair samples were collected on days 0, 1, 2, 3, 7, 30, 60, and 90 and analysed for AFB1 and AFM1 using UHPLC-MS/MS. AFB1 and AFM1 were detected in 75% and 13.6%, respectively, of the day 1 to day 7 urine samples. AFB1 was detected in hair samples collected from day 3 up to day 60. This is the first report to confirm the deposition of AFB1 in the hair of experimental animals. These findings indicate that hair analysis has the potential to provide an accurate long-term historical record of aflatoxin exposure with potentially important implications for the field of aflatoxin biomarkers.

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