34 research outputs found
Supercritical fluid extraction and analysis of indigenous medicinal plants for uterotonic activity.
Thesis (Ph.D.)-University of Natal, Durban, 1997.Ingestion of extracts prepared from various medicinal plants to induce or augment labour
is common amongst Black South African women during the late stages of pregnancy.
This applies particularly to the rural areas where modern health care facilities are often
lacking. Many of these plants have not been investigated scientifically and one needs to
substantiate claims of quality, safety and efficacy. Furthermore, it is believed that the
consumption of these plant extracts can result in foetal meconium staining at delivery.
An investigation into the uterotonic properties of three plants viz. Ekebergia capensis
Sparrm. Clivia miniata (Lindl.) Regel. and Grewia occidentalis L. were carried out using
guinea pig uterine smooth muscle in vitro. Supercritical fluid extraction was performed
with water modified supercritical carbon dioxide to extract the uterotonic components.
An attempt was also made to couple supercritical fluid extraction directly on-line to the
bioassay so that on line screening of crude plant extracts could be performed within short
periods of time. The effects of supercritical CO2 decompression on temperature and pH of
the muscle bathing solution were considered since these factors affect muscle
contractility. The direct effects of excess CO2 on intracellular mechanisms were
eliminated by constructing a CO2 reduction interface together with passage of carbogen
which aided in the rapid displacement of excess CO2, As samples of these extracts were
found to induce muscle contraction, supercritical fluid fractionation (SFF) was performed
by sequentially increasing the fluid density. Extracted fractions were obtained by
sequentially increasing the pressure at constant temperature and modifier concentration in
an attempt to identify the active fractions. Extractions were performed at 200 atm, 300
atm and 400 atm respectively. Subsequent testing of these fractions enabled the detection
of active and inactive fractions as well as a fraction that had a spasmolytic effect on
uterine muscle. The 400 atm extracts of E. capensis and C. miniata displayed maximum
activity while only the 300 atm extract of G. occidentalis induced uterine muscle
contraction. Subsequent analysis of the sequentially extracted fractions, by high
performance liquid chromatography and micellar electrokinetic capillary chromatography
revealed that certain compounds present in the fractions that stimulated muscle
contraction, were sensitive to the extraction pressure hence making it possible to
determine the compounds that were likely to be active. Column chromatography
followed by various spectroscopic techniques were performed in an attempt to isolate and
elucidate the structures of the compounds that were present in the plant extracts. The
extract of Ekebergia capensis yielded five known compounds (B-sitosterol, oleanonic
acid, 3-epioleanolic acid, 2,3,22,23-tetrahydroxy-2,6,1 0, 15,19 ,23-hexamethyl-6, 10, 14, 18-
tetracosatetrene and 7-hydroxy-6-methoxy coumarin. The extract of Clivia miniata
yieded linoleic acid and 5-hydroxymethyl-2-furancarboxaldehyde while the extract of
Grewia occidentalis yielded 3-(4-hydroxy-3-methoxyphenyl)-2-propenal, a novel
compound 2,2' ,6,6'-tetramethoxy-4'-al-4-(w-oxo-E-propenyl)-biphenyl and oleanonic
acid. The pure compounds were further evaluated pharmacologically to identify the
active components and assess the physiological mode of action by the use of various
receptor blockers. Oleanonic acid, 3-epioleanolic acid, linoleic acid and 5-
hydroxymethyl-2-furancarboxaldehyde and 3-(4-hydroxy-3-methoxyphenyl)-2-propenal
were found to induce an agonistic muscle response. All these compounds were observed
to mediate their effects through the cholinergic receptors. The results obtained in this
study supports the claim of these plants possessing uterotonic properties
A chemical investigation of a KwaZulu-Natal medicinal plant, Momordica foetida Schum. & Sond.
Thesis (M.Sc.)-University of Natal, Durban, 1994.Momordica foetida Schum. & Sond. (Cucurbitaceae), locally known as
iNtshungu, is widely used by the Zulu people of Natal-KwaZulu for the
treatment of a variety of ailments.
The dried leaves leaves and stems of this plant was subjected to soxhlet
extraction by refluxing with hexane, chloroform and methanol successively.
Thin layer chromatography of the chloroform extract of the leaves revealed a
multiplicity of compounds. The chloroform extract was further partitioned with
sodium hydroxide resulting in an organic and aqueous phase. The organic
phase, containing extract A, afforded two compounds, viz. compounds 1 and 2.
The basic aqueous fraction was neutralised and re-extracted with chloroform to
give extract B, affording five compounds, viz. compounds 3,4,5,6 and 7.
Structural elucidation was accomplished by techniques such as IH and 13C NMR
spectroscopy, HETCOR, COSY, FTIR and High Resolution Mass
Spectrometry.
Compounds 1 and 2 were identified as cucurbitane triterpenoids known as
momordicines which had been previously discovered in the related species of
this plant, Momordica charantia L. The remaining five compounds were
identified as novel compounds, although natural derivatives of compounds 6
and 7 had been isolated previously from Momordica charantia L. Compounds
3-7 were each isolated as an epimeric mixture but it was possible to select the
resonances corresponding to the major epimer. These five epimers were
respectively identified as 5, 19-epoxy-19(R)-hydroxy-25-methoxy-5β-
cucurbita-6,23-diene-3β-ol [102], 5,19-epoxy-19(R),25-dihydroxy-5β-cucurbita-
6,23-diene-3β-ol [103], 5,19-epoxy-19(R)-methoxy-25-hydroxy-5β-cucrbita-
6,23-diene-3β-ol [104], 5,19-epoxy-25-methoxy-5β-cucurbita-6,23diene-
3β-ol [105] and 5,19-epoxy-19(R),25-dimethoxy-5β-cucurbita-6,23diene-
3β-ol [106].
Appropriate reactions were performed, where possible, on the compounds
isolated in order to confirm their identity
Cisplatin-Associated Ototoxicity: A Review for the Health Professional
Cisplatin is an effective drug used in the treatment of many cancers, yet its ototoxic potential places cancer patients, exposed to this drug, at risk of hearing loss, thus negatively impacting further on a patientâs quality of life. It is paramount for health care practitioners managing such patients to be aware of cisplatinâs ototoxic properties and the clinical signs to identify patients at risk of developing hearing loss. English peer-reviewed articles from January 1975 to July 2015 were assessed from PubMed, Science Direct, and Ebscohost. Seventy-nine articles and two books were identified for this review, using MeSH terms and keywords such as âototoxicityâ, âcisplatinâ, âhearing lossâ, and âototoxicity monitoringâ. This review provides an up-to-date overview of cisplatin-associated ototoxicity, namely, its clinical features, incidence rates, and molecular and cellular mechanisms and risk factors, to health care practitioners managing the patient with cancer, and highlights the need for a team-based approach to complement an audiological monitoring programme to mitigate any further loss in the quality of life of affected patients, as there is currently no otoprotective agent recommended routinely for the prevention of cisplatin-associated ototoxicity. It also sets the platform for effective dialogue towards policy formulation and strengthening of health systems in developing countries
Systematic Review of Genetic Factors in the Etiology of Esophageal Squamous Cell Carcinoma in African Populations
Background: Esophageal squamous cell carcinoma (ESCC), one of the most aggressive cancers, is endemic in Sub-Saharan Africa, constituting a major health burden. It has the most divergence in cancer incidence globally, with high prevalence reported in East Asia, Southern Europe, and in East and Southern Africa. Its etiology is multifactorial, with lifestyle, environmental, and genetic risk factors. Very little is known about the role of genetic factors in ESCC development and progression among African populations. The study aimed to systematically assess the evidence on genetic variants associated with ESCC in African populations. Methods: We carried out a comprehensive search of all African published studies up to April 2019, using PubMed, Embase, Scopus, and African Index Medicus databases. Quality assessment and data extraction were carried out by two investigators. The strength of the associations was measured by odds ratios and 95% confidence intervals. Results: Twenty-three genetic studies on ESCC in African populations were included in the systematic review. They were carried out on Black and admixed South African populations, as well as on Malawian, Sudanese, and Kenyan populations. Most studies were candidate gene studies and included DNA sequence variants in 58 different genes. Only one study carried out whole-exome sequencing of 59 ESCC patients. Sample sizes varied from 18 to 880 cases and 88 to 939 controls. Altogether, over 100 variants in 37 genes were part of 17 case-control genetic association studies to identify susceptibility loci for ESCC. In these studies, 25 variants in 20 genes were reported to have a statistically significant association. In addition, eight studies investigated changes in cancer tissues and identified somatic alterations in 17 genes and evidence of loss of heterozygosity, copy number variation, and microsatellite instability. Two genes were assessed for both genetic association and somatic mutation. Conclusions: Comprehensive large-scale studies on the genetic basis of ESCC are still lacking in Africa. Sample sizes in existing studies are too small to draw definitive conclusions about ESCC etiology. Only a small number of African populations have been analyzed, and replication and validation studies are missing. The genetic etiology of ESCC in Africa is, therefore, still poorly defined
An overview of cancer research in South African academic and research institutions, 2013 - 2014
Background and objectives. Cancer is emerging as a critical public health problem in South Africa (SA). Recognising the importance of research in addressing the cancer burden, the Ministerial Advisory Committee on the Prevention and Control of Cancer (MACC) research working group undertook a review of the current cancer research landscape in SA and related this to the cancer burden.Methods. Academic and research institutions in SA were contacted to provide information on the titles of all current and recently completed (2013/2014) cancer research projects. Three MACC research working group members used the project titles to independently classify the projects by type of research (basic, clinical and public health â projects could be classified in more than one category) and disease site. A more detailed classification of projects addressing the five most common cancers diagnosed in males and females in SA was conducted using an adapted Common Scientific Outline (CSO) categorisation.Results. Information was available on 556 cancer research projects. Overall, 301 projects were classified as clinical, 254 as basic science and 71 as public health research. The most common cancers being researched were cancers of the breast (n=95 projects) and cervix (n=43), leukaemia (n=36), non-Hodgkinâs lymphoma (n=35) and lung cancer (n=23). Classification of the five most common cancers in males and females in SA, using the adapted CSO categories, showed that the majority of projects related to treatment, with relatively few projects on prevention, survivorship and patient perspectives.Conclusion. Our findings established that there is a dearth of public health cancer research in SA
Risk factors for oesophageal cancer in the Eastern Cape Province of South Africa
Includes bibliographical references (p. 196-245).A multicenter hospital-based case-control study with incidence density sampling was conducted between November 2001 and February 2003 to assess the impact of social and dietary habits, and the consumption of dietary and medicinal wild plants on the risk of developing oesophageal cancer (OC) among residents of the Eastern Cape Province of South Africa. The study was conducted on 670 incident cases (98/% response rate) and 1188 controls (96/% response rate) attending either of the three major referral hospitals in the Province, i.e Umtata General, Frere and Cecilia Makiwane Hospitals
Risk factors for oesophageal cancer in Uruguay
Bibliography: leaves 51-59.The objective of this study was to evaluate matĂŠ consumption as a risk factor for oesophageal cancer and to further evaluate the role of quantity and temperature in order to assess whether the effect is related to the carcinogenicity of the plant or the high temperature at which matĂŠ is consumed. In addition the effect of diet, alcohol drinking and tobacco smoking on oesophageal cancer risk was assessed
Barriers to cervical cancer screening in Africa: a systematic review
Abstract Introduction Africa has one of the highest burdens of cervical cancer in the world. The unacceptably high incidence and mortality rates could be reduced through implementing a comprehensive approach to its prevention and control that includes screening, which however, is low in most low-and-middle-income countries. Hence, this systematic review aims at exploring factors that prevent women from utilising cervical cancer screening services in the region. Methods A mixed method systematic review was conducted. A search was performed on PubMed (Medline), EMBASE, CINAHL (EBSCOHOST) and Scopus databases for articles published until May 2019 without time, language or study design limits. Two reviewers critically appraised the included studies independently using the standard quality assessment criteria for evaluating primary research papers. Results of the quantitative and mixed methods studies were transformed into qualitative data and synthesised using thematic analysis. Results From a potential 2 365 studies, 24 from 11 countries met the eligibility criteria and were selected; eight qualitative, 13 quantitative, and three that used the mixed-method approach. The primary barriers were identified as poor access to screening services, lack of awareness and knowledge on cervical cancer and screening, and socio-cultural influences. Service providers perceived lack of skills, screening equipment and supplies, and staff shortages as the major barriers to the provision of screening services. Conclusion Barriers to cervical cancer screening in Africa are multifaceted and require a holistic approach that will address them concurrently at the health system, individual, interpersonal, community and structural levels. Political will complimented by stakeholder involvement is required in the development and implementation of strategies that will ensure acceptability, availability, accessibility, and affordability of screening to minimise barriers in accessing the service
Cytokeratin expression in gastrointestinal stromal tumors: Morphology, meaning, and mimicry
Background: Gastrointestinal stromal tumors (GISTs) are biologically distinctive neoplasms harboring KIT and PDGFRA mutations. Cytokeratin expression in GISTs is an under-recognized diagnostic pitfall, especially in high grade GISTs with limited biopsy material and from metastatic sites. Materials and Methods: We evaluated the histomorphology and expression of four â˛broad-spectrumⲠcytokeratin markers, AE1-AE3, CAM 5.2, MNF-116, and 34βE12 in 64 GISTs diagnosed over a 68-month period. Individual cytokeratins 5, 6, 7, 8, 14, 17, 18, 19, and 20 were investigated in the â˛broad-spectrumⲠcytokeratin-positive GISTs. Results: Of 64 GISTs, 10 (15%) demonstrated cytokeratin immunopositivity. All 10, considered high risk by the National Institutes of Health consensus approach, were immunopositive for CAM 5.2 and MNF-116. Seven were AE1-AE3 immunopositive. Cytokeratins 8 and 18 were confirmed in 10 and 9 GISTs, respectively. One GIST demonstrated biphasic morphology with cytokeratin immunonegativity in low-grade spindle and immunopositivity in high-grade epithelioid foci. KIT and PDGFRA mutational analysis, undertaken in 5/10 cytokeratin-positive GISTs, harbored KIT exon 11 mutations. Conclusion: We hypothesize that cytokeratin expression exclusively in high risk GISTs is a consequence of tumor progression. Given the increasing number of commercially available broad-spectrum cytokeratin immunomarkers, including those reacting with cytokeratins 8 and 18, cytokeratin-positive GISTs must be differentiated from carcinomas, melanomas, and a range of cytokeratin-positive sarcomas to ensure optimal patient management and prognostication