Masters Degrees (Plant Sciences)
Permanent URI for this collection
Browse
Browsing Masters Degrees (Plant Sciences) by Author "Ashafa, A. O. T."
Now showing 1 - 5 of 5
Results Per Page
Sort Options
Item Open Access Antimycobacterial activities of selected plants used in the management of tuberculosis in Sekhukhune (Limpopo Province), South Africa(University of the Free State (Qwaqwa Campus), 2017) Madisha, Jacobus Kori; Ashafa, A. O. T.; Aiyegoro, A. O.Tuberculosis (TB) continues to be a devastating disease of the world affecting more than two million people annually with one-third of the world’s populations suffering from the menace. The management of TB was in the use of orthodox medicines which are not only expensive but presents severe side effects. Thus, efforts are recently geared towards the use of alternative therapy from natural sources which could offer a lasting solution to the treatment of the diseases with little or no side effects. The study investigated the antimicrobial potentials of four medicinal plants used by Bapedi tribe of Sekhukhune area, Limpopo Province of South Africa. The antimycobaceterial efficacy of Aloe marlothii, Maerua angolensis, Drimia elata and Elephantina elephantorrhiza which were selected based on ethnobotanical study carried-out in the study was tested in four solvents such as ethanol, methanol, hydroethanol and dichlrormethane against four mycobacterium species such as M. tuberculosis, M. smegmatis, M. peregrinum, M. haemophilus and other gram positive and gram negative bacteria isolates using agar well dilution method and streak plate disc diffusion assay as a way of validating the anti-tuberculosis potentials of the plants. The results revealed the anti TB activity of the four plants particularly M. angolensis, D. elata and E. elephantorrhiza which were reported for the first time in this study. Similarly, the results revealed varied degrees of antimycobacterial activities of most of the screened extracts (particularly ethanolic and methanol) going by the zone of inhibition values (10 – 32 mm) as well as minimum inhibitory concentration (MIC) values that fell within the range of 0.098 - 1.56 μg/mL and as such, could be adjudged to possess anti TB potentials. Conclusively, the anti TB activity witnessed by the four plants could be attributed to the presence of the secondary metabolites which are responsible for the elicited effect. The study also validates the use of these plants in the management of tuberculosis by the Sekhukhune people of Limpopo Province, South Africa.Item Open Access Antioxidant and antidiabetic potentials of Medicago laciniata (L) Mill root extracts: in vitro investigations(University of the Free State (Qwaqwa Campus), 2017) Tshabalala, B. D.; Ashafa, A. O. T.; Balogun, F. O.; Sabiu, S.Diabetes mellitus (DM) is one of the chronic ailments that contribute to high mortality rate worldwide. Synthetic drugs used to control and manage this disease have several constrictions like prohibitive price to the unemployed class and or low-income earners, disturbing side effects such as use during pregnancy. Due to these constraints and others, an alternative approach to control and manage DM is highly required. The aim of the current study was to investigate the in vitro antioxidant and antidiabetic potentials of Medicago laciniata (L) Mill root extracts. Solvents used for extraction of the plant material were hydro-ethanol, ethanol, water and acetone. Assays carried out in this investigation were phyto-chemical screening (qualitative and quantitative methods), antioxidant assays (DPPH radicals, reducing power, metal chelating, hydrogen peroxide, hydroxyl radicals and nitric oxide assays), and antidiabetic assays (alpha amylase and alpha glucosidase inhibition). Results showed that M. laciniata root possesses several medicinal phyto-chemicals like alkaloids, flavonoids, flavonols, saponins, tannins, cardiac glycosides and phenols. Quantification of phyto-chemicals showed 0.632 (μg/mL), 0.151(mg/g), 0.035 (mg/g) and 0.032 (mg/g) contents of total flavonoids, total flavonols, total phenols and total tannins respectively, while alkaloids and saponins showed 27 and 78% respectively. Antioxidant results revealed varied IC50 values of extracts in different assays performed. The lowest IC50 values recorded were 0.602±0.034 mg/mL, 0.712±0.072 mg/mL, 0.512±0.002 mg/mL, 0.306±0.021 mg/mL, 0.513±0.041 mg/mL and 0.455±0.164 mg/mL in DPPH radicals, reducing power, metal chelating, hydrogen peroxide, hydroxyl radicals and nitric oxide assay respectively. Hydro-ethanol extract showed the strongest alpha glucosidase inhibition with the lowest IC50 value of0.07±0.014 mg/mL while acarbose (standard) showed 0.24±0.17 mg/mL. All extracts showed poor alpha amylase inhibitory potential as compared to acarbose which was recorded to have the lowest IC50 value of 0.60±0.191 mg/mL. Among other extracts, ethanol extracts showed better alpha amylase inhibition with an IC50 value of 2.11±0.026mg/mL. Results obtained from different assays in this study suggest that Medigaco laciniata (L) Mill have antioxidant and antidiabetic potentials; may also possess other medicinal properties due to the variety of phyto-chemical discovered in this plant. Hence the study justified the folkloric use of this plant.Item Open Access Chemical composition and antimicrobial activity of different root extracts of Hermannia geniculata against human pathogens of medical importance(University of the Free State (Qwaqwa Campus), 2015-12) Mojau, Pheello Jeremia; Ashafa, A. O. T.Hermannia geniculata has been used widely as traditional medicine for treatment agai nst infectious human pathogens. The aim of the study was to determine the antibacterial and anti fungal activities of H. geniculata root extracts and their fractio ns against 16 microbial strains. The dried plant materials were extracted separately in 150 ml of methanol, acetone, ethanol, water and 150 ml (50/50) of hydro-ethanol. Acetone extract inhibited the growth of microorganisms with minimum inhibitory concentration (MIC) values of 1.56 mg/ml against all the tested strains except for Salmonella typhimurium and Candida rugosa at the concentration of 6.25 mg/ml. The ethanol, hydro-ethanol and methanol extracts inhibited bacterial growth with MIC values ranging from3. l 3 mg/ml to 12.50 mg/ml, while water extract had MIC of 12.50 mg/ml against all tested bacterial and fungal strains. Acetone extract had maximum bactericidal concentration (MBC) values ranging from 1.56 to 3.13 mg/ml against most microorganisms. Butanol fraction of acetone extract had MIC of 0.78 mg/ml against Staphylococcus aureus (OK.2b) and Staphylococcus a11re11s (ATCC 6538), whilst the ethyl acetate had the lowest MBC of 1.56 mg/ ml against S. aureus (OK.lb), S. aureus (ATCC 6538), and Streptococcus .faecalis. The extracts and their respective fractions displayed similar inhibitory properties which are indica tions that either the crude extract or their fractions could be used to manage infections assoc iated with bac teria and fungi.Item Open Access Comparative insecticidal properties of Basotho medicinal plants against Culex quinquefasciatus (Diptera: Culicidae) mosquitoes from the Eastern Free State Province of South Africa(University of the Free State (Qwaqwa Campus), 2015-01) Modise, S. A.; Ashafa, A. O. T.Culex quinquefasciatus is a vector of human and animal disease causing pathogens that are of socioeconomic problem in developing countries. The mosquitoes have developed resistance against synthetic insecticides, hence the search for natural botanical insecticides. The present study was aimed at investigating the secondary plant metabolites, cytotoxicity, larvicidal, pupicidal and insecticidal potential of Artemisia absinthium, Artemisia afra, Cosmos bipinnatus, Foeniculum vulgare, Mentha longifolia and Tagetes minuta against C. quinquefasciatus. The leaf extracts contained mostly saponins, alkaloids, terpenoids, steroids and flavonoids. Plant aqueous and ethanol extracts exhibited cytotoxic effects for T. minuta (LC50 = 0.10 mg/ml; LC50 = 3.16 mg/ml), A. absinthium (LC50 = 2.89 mg/ml), C. bipinnatus (LC50 = 5.66 mg/ml; LC50 = 4.81 mg/ml), and A. afra (LC50 = 5.39 mg/ml) against brine shrimp nauplii. Ethanolic extract mortality and concentration doses had was significant difference (F5,5 = 13.69; P < 001) towards nauplii mortality. Most larvicidal bioactivities were observed in ethanolic and hexane extracts for F. vulgare (LC50 = 0.10 mg/ml; LC50 = 1.03 mg/ml), M. longifolia (LC50 = 1.05 mg/ml; LC50 = 0.10 mg/ml), T. minuta (LC50 = 1.17 mg/ml; LC50 = 1.01 mg/ml) and A. afra (LC50 = 1.02 mg/ml; LC50 = 1.14 mg/ml), and while larvae mortality and extract concentrations showed significant difference (F5,5 = 9.95; P < 0.01). Pupicidal bioactivity was displayed by both ethanolic and hexane extracts of A. afra (LC50 = 1.10 mg/ml; LC50 = 1.04 mg/ml), T. minuta (LC50 = 1.11 mg/ml; LC50 = 1.12 mg/ml), C. bipinnatus (LC50 = 1.14 mg/ml; LC50 = 1.16 mg/ml) and M. longifolia (LC50 = 1.13 mg/ml; LC50 = 1.21 mg/ml). The extract concentration level were directly proportional to pupa mortality percentage with M. longifolia (R2 = 0.85) and A. afra (R2 = 0.74). The aqueous extracts had no fatal effect on larvae and pupa at all the concentrations tested. The rate of knock-down was highest for M. longifolia (KD50 = 4.91 min-1) followed by F. vulgare (KD50 = 9.87 min-1), T. minuta (KD50 = 12.39 min-1), and A. afra (KD50 = 19.02 min-1). The insecticidal activity was greater in M. longifolia (LD99 = 0.25 g) followed by F. vulgare (LD99 = 0.25 g), T. minuta (LD99 = 0.25 g) and A. afra (LD99 = 0.25 g). The insecticidal mortality ratio between evaluated plants had significant difference (F5,4 = 283.11; P < 0.01). In this study, ethanolic and aqueous extracts had more cytotoxic activity against A. salina nauplii than the hexane extracts, whereas, ethanolic and hexane extracts exhibited stronger larvicidal and pupicidal activities than the aqueous extracts. The selected Basotho medicinal plants possessed convincing insecticidal, pupicidal and larvicidal activities and therefore can be recommended for mosquito control at Kroonstad as well as in nearby communities of the eastern Free State Province.Item Open Access Isolation of bioactive compounds and in vitro studies on Pentanisia prunelloides (Klotzsch ex Eckl. & Zeyh.) Walp. used in the eastern Free State for the management of diabetes mellitus(University of the Free State (Qwaqwa Campus), 2017-01) Makhubu, F. N.; Ashafa, A. O. T.; Fouchè, G.The pravelence of diabetes mellitus is increasing and it is one of the major health problems affecting the world. The challenges with synthetic drugs used in the treatment of hyperglycemia such as acarbose and miglitol include abdominal discomfort, bloating and diarrhoea. The present study isolated and evaluated the active antidiabetic constituents from the roots of Pentanisia prunelloides (Rubiaceae) from the eastern Free State Province of South Africa using in vitro models. The antidiabetic potential of the water, ethanol, aqueous-ethanol and hexane root extracts of P. prunelloides was investigated against the specific activities of α-amylase, α-glucosidase, sucrase and maltase. Furthermore, the antioxidant activity of the extracts was determined using iron chelation, 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and superoxide anion radical scavenging assays. For the fractions and the isolated compounds, only α-amylase and α-glucosidase assays were used. Fractionation of the ethanol extract was done by vacuum liquid chromatography (VLC), fractions were combined according to thin layer chromatography (TLC) profiles, and further purification of semi-pure compounds was achieved using preparative thin layer chromatography (pTLC) to obtain pure compounds. Isolated compounds were characterised using nuclear magnetic resonance (NMR) (1D and 2D data) and mass spectroscopy (MS). The ethanol extract displayed significantly higher (p < 0.05) inhibition of α-amylase (18.51 μg/mL), hexane (18.08 μg/mL) and ethanol (19.73 μg/mL) extract exhibited strongest inhibition of α-glucosidase. Water extract demonstrated strong inhibition of sucrase (3.85 μg/mL), and aqueous-ethanol extract (26.03 μg/mL) on maltase. Kinetic studies showed that the mode of inhibition of α-amylase and α-glucosidase by ethanol extract was mixed non-competitive and non-competitive respectively. Water and ethanol extract displayed higher DPPH (75.42 μg/mL) and (77.06 μg/mL) scavenging abilities than other extracts but not higher than gallic acid. Hexane extract demonstrated significantly higher (p < 0.05) superoxide (0.33 μg/mL) and hydroxyl radical (0.51 μg/mL) scavenging abilities while aqueous-ethanol exhibited the strongest iron chelation activity 4.24 μg/mL. Phytochemical analysis of the extract revealed the presence of tannins, terpenoids, alkaloids, saponins, flavonoids and cardiac glycosides. Quantification of phytochemicals revealed total flavonoids of 15.40 mg quercetin equivalent (QE)/g in hexane extract which was not significant (p > 0.05) and from water it was 14.70 mg QE/g. The highest tannin concentration of 45.60 mg gallic acid equivalent (GAE)/g was from aqueous-ethanol which was significantly higher than other extracts (p < 0.05). Total phenol from water and aqueous extracts was 0.07 mg GAE/g; alkaloids and saponins were found to be low in the roots of P. prunelloides, at 0.6 and 13.9% respectively. Of the 21 fractions obtained, acetylated fraction displayed significantly higher (p < 0.05) inhibition of α-amylase 48.06 μg/mL while fraction PP-I-101835BII exhibited strongest inhibition of α-glucosidase (19.53 μg/mL). Three compounds were isolated, two sucrose (acetylated and non-acetylated) and tormentic acid. Tormentic acid inhibited α-amylase and α-glucosidase at 70.45 μg/mL and 28.21 μg/mL respectively. Kinetic analysis revealed that tormentic acid inhibited α-amylase in un-competitive manner and α-glucosidase competitively. The ethanol extract and the isolated tormentic acid exhibited best inhibitory activity on the two enzymes studied, and the presence of phytochemicals in the roots of P. prunelloides in this study may be suggested to have contributed greatly to the biological activities of the plant. Tormentic acid appears to be a potential anti-diabetic drug thus supporting usage of the root extract of P. prunelloides in the management and treatment of diabetes mellitus in the eastern Free State Province.