Kenyatta University Repository
Kenyatta University Institutional Repository is a digital archive that collects, preserves and disseminates scholarly outputs of the Institution
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Therapeutic Promise of Aqueous Extract of Portulaca oleracea L.: Antioxidant and Anti-Inflammatory Effects
(Kenyatta University, 2025-08) Wanderi, Gladys Wamaitha
Oxidative stress is an imbalance in which oxidants exceed antioxidants in the body's
defense system. Several chronic diseases, including rheumatoid arthritis, cardiovascular
disorders and cancer are caused by oxidative stress. Inflammation refers to biological
responses caused by oxidative stress, toxic substance, irradiation and pathogens. Synthetic
antioxidant and anti-inflammatory drugs already on the market are linked to adverse
effects, necessitating the need for an alternative medicinal approach. Portulaca oleracea is
used by communities living in Embu County to manage inflammation. Nevertheless, the
scientific data to confirm this claim was lacking. This study aimed to assess in vitro
antioxidant and ex vivo anti-inflammatory effects, including qualitative phytochemical
analysis of Portulaca oleracea. Fresh plant sample was obtained from Embu County,
Kenya. The sample was air-dried, milled, macerated with water and then freeze dried to
obtain a solid extract. The 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging,
H2O2 radical scavenging, ferric reducing antioxidant power (FRAP), total phenolic content
(TPC) and total flavonoid content (TFC) were among the antioxidant assays that were
performed according to standard methods. The antioxidant assays used the extract at
concentrations of 7, 15, 31, 62, 125, 250, 500 and 1000 µg/ml. In antioxidant assays,
ascorbic acid was utilized as the standard. The standards that were used in TFC and TPC
assays were rutin and gallic acid, respectively. The ex vivo anti- inflammatory assays
included hypotonicity-induced hemolysis, heat-induced hemolysis, albumin denaturation
and anti-proteinase activity. Indomethacin was utilized as reference drug in the ex vivo antiinflammatory assays. The extract and reference drug used concentrations of 7, 15, 31, 62,
125, 250, 500 and 1000 µg/ml. Standard procedures were used to conduct a qualitative
phytochemical analysis. Analyzed data was summarized using mean and the standard error
of the mean. Statistical differences between the different concentrations were evaluated
using one-way analysis of variance and Tukey's multiple comparisons. Effects of ascorbic
acid/Indomethacin and the extract were compared statistically using independent T-test. If
p value was <0.05, statistical results were deemed significant. This study found that
Purslane oleracea extract possesses potent in vitro antioxidant effect through FRAP, as
well as DPPH radical scavenging and H2O2 radical scavenging activities. The extract also
revealed considerable amount of TPC and TFC, which are linked with antioxidant effects.
The extract also demonstrated ex vivo anti-inflammatory effect via inhibitions of:
hypotonicity-induced hemolysis, heat-induced hemolysis, albumin denaturation, as well
anti-proteinase activity. A concentration- dependent response was seen in the extract's in
vitro antioxidant and ex vivo anti- inflammatory activities. For instance, at the highest
concentration of extract(1000 µg/ml), the extract had its highest percentage inhibition on
heat-induced hemolysis (72.65%) and its lowest inhibitory percentage (27.14%) at the
lowest concentration of(7µg/ml) Phytocompounds including flavonoids, alkaloids,
steroids, saponins, terpenoids, cardiac glycosides, tannins, and phenolic acids were
detected in the extract according to a qualitative phytochemical analysis. These
phytocompounds were linked to the two activities mentioned in this study. The current
study concluded that the extract possesses potent in vitro antioxidant and ex vivo antiinflammatory effects. The study recommends that the aqueous extract of Purslane oleracea
can be used to develop alternative anti- inflammatory and antioxidant agents.
Exploring the Population Structure and Genetic Diversity of Moringa oleifera Using DArTseq-Derived SNP Markers
(Kenyatta University, 2025-11) Ndalo, Jantor
Moringa oleifera is a versatile tree native to the foothills of the Himalayas and now naturalized in the tropics. Moringa is nutritionally significant owing to its high nutrient and antioxidant content. Despite its increasing use as a fodder crop, wood fuel, medicine, an anticoagulant and a potential source of biodiesel, the genetic diversity of Moringa across the tropics remains a subject of intense investigation. Previous studies have used hybridization-based methods such as microsatellites which have not fully resolved its genetic diversity. In this study, genetic diversity and structure of 95 accessions of Moringa from tropical regions were analyzed using single nucleotide polymorphisms. Genomic DNA was extracted from 19 provenances collected from Africa, Caribbean and Southeast Asia. 3968 SNP markers were identified using DArTSEQ technology, which combines complexity reduction methods with next-generation sequencing. These were culled to a final set of 1913 informative markers that were then used for population structure and genetic diversity analysis. Unweighted neighbour joining phylogeny and principal coordinate analysis revealed four distinct clusters related to the geographic origin: Caribbean (Haiti/Jamaica) and East African (Kenya/Tanzania) were identified to be a subset of the West African (Mali/Ghana) population while the Southern African (Malawi) segregated distinctly. Philippines samples clustered separately and farthest as expected. Analysis of molecular variance revealed high gene flow within populations (77 %) compared to among populations (23 %). Bayesian modelling in structure with best k being two still distinctly segregated the Southern African (Malawi) population from the other African regions suggesting a distinct introduction. The significant admixture of individuals noted in structure is typical of unnatural introductions possibly through anthropogenic events. This study highlights the power of SNP markers from DArTSEQ technology in elucidating the genetic structure and molecular diversity of Moringa oleifera. Malawi and Philippines being the most diverse should be considered as candidates for conservation improvement and utilization since they have higher ecosystem functioning. The discovered SNPs enable genome-wide association studies to accelerate marker-assisted breeding. These results too have implications for germplasm collection, improvement, conservation, utilization strategies and policies. Further research utilizing advanced genomic tools will enhance our knowledge of Moringa oleifera and support its sustainable utilization for various applications.
Capital Expenditure Announcements and Stock Returns of Firms Listed at the Nairobi Securities Exchange, Kenya
(Kenyatta University, 2025-11) Jackson Sankale Keton
Capital expenditure announcements by listed companies constitute one of several avenues through which rational investors seek to realize gains in the form of stock returns. Within the framework of market efficiency, such announcements would not be expected to generate excess returns, as the information should already be incorporated into prevailing stock prices. Empirical research conducted in both advanced and emerging economies has produced mixed evidence regarding the market response to capital expenditure announcements, with some studies reporting positive investor reactions while others find no statistically significant effects. At the Nairobi Securities Exchange (NSE), episodes of inconsistent stock return patterns suggest deviations from strict market efficiency. The aim of this study was to investigate the impact of capital expenditure announcements on stock returns of firms listed at the Nairobi Securities Exchange, Kenya. Specifically, the study sought to determine the effect of product diversification announcements, examine the effect of asset expenditure announcements, and investigate the effect of research and development announcements on stock returns at the NSE. The study was grounded on four key theories: Efficient Market Hypothesis (EMH), Random Walk Theory, Arbitrage Pricing Theory (APT), and the Theory of Rational Expectations. A causal research design was adopted, encompassing all sixty-three companies listed on the NSE between 2012 and 2025. From this population, a purposive and judgmental sampling strategy was applied to select six firms that had issued capital expenditure announcements during the study period. Secondary data were obtained from the NSE and Financial Times databases, and data collection was facilitated through a desk review instrument. Analytical procedures were undertaken using Microsoft Excel. The study employed an event study methodology, utilizing the market model to estimate abnormal stock returns within the event window surrounding announcement dates. The analyzed data were found to be normally distributed. The study found that product diversification announcements had an effect on stock returns, whereas asset expenditure and research and development announcements had no effect on stock returns at the NSE. Aggregation of the three categories revealed that, overall, capital expenditure announcements have no significant effect on stock returns at the NSE. The study recommends that organizations should strategically use product diversification announcements to boost investor confidence, supported by sound financial analysis. Investors and analysts should monitor these announcements closely while adopting a long-term view for asset expenditure and R&D disclosures. Regulators such as the CMA and NSE should enforce timely and transparent disclosure of material information to enhance market efficiency and reduce information asymmetry. Strengthening disclosure standards and best practices in investor communication will improve market integrity and optimize decision-making.
Immune Enhancing Potential of Moringa Oleifera Leaf Powder in Hiv/Aids Patients at Mbagathi County Hospital, Nairobi, Kenya
(Kenyatta University, 2025-10) Wasonga,Wilbroda
Human immunodeficiency virus (HIV) infection is managed by the use of ARVs,
which are expensive, cause side effects, and are associated with drug resistance and
drug failure. The use of nutritional remedies in the management of HIV/AIDS is
becoming popular. The purpose of the study was to investigate the immune
enhancing potential of Moringa oleifera in the treatment of HIV/AIDS patients. The
information obtained from this study will provide insight into alternative remedies
to reduce the burden of HIV/AIDS. A Quasi-Experiment of the regression
discontinuity type was carried out at the Comprehensive Care Center, Mbagathi
County Hospital, Nairobi, Kenya. One hundred and seventy-three HIV seropositive
participants on ARV treatment and also attending the regular clinic were allocated
to either the intervention group (n=99) supplemented with Moringa oleifera leaf
powder, or the control group (n=74), which was a separate comparative group not
supplemented. The participants were followed for six months from February 2019
to July 2019. Immune functions were assessed by CD4+ T cell counts, CD8+ T cell
counts, total lymphocyte counts, and viral load measurements. All these tests were
taken at baseline, at the end of the third and sixth months of the study period.
Hematological parameters were assessed by white blood cell (WBC) counts,
platelet (PLT) counts, red blood cell (RBC) counts, and hemoglobin (HB) levels.
Toxicity was assessed by determination of liver and kidney functions by using the
Cock Croft formula (CGF). Data was analyzed using STATA 12.1. Estimates of
mean and standard deviation were obtained by descriptive analysis. The normality
test for the data was conducted by using the Shapiro-Wilk test. One-way Analysis
of variance tests (ANOVA) followed by Tukey’s post hoc tests were used to
determine the significance of the mean difference in immunological, hematological,
weight, body mass index (BMI), and creatinine levels between the two groups. The
study group was further subdivided into subsets based on their baseline immune
parameters and levels of immunity. All these tests were conducted at 95%
confidence intervals. Over the study period, the results showed no significant
difference in CD4+ T cell counts (p= 0.523), CD8+ T cell count (p= 0.908), total
lymphocyte counts (p= 0.185) WBC (p= 0.327), HB (p= 0.490), PLT (p= 0.250)
weight gain (p= 0.251), BMI (p= 0.868), and creatinine levels (p= 0.103) between
the two groups. The RBC count of the control group was significantly higher
compared to that of the intervention group (p= 0.003). It was observed that
supplementation with M. oleifera has no effect on the immune functions and
hematological parameters of HIV patients. It was also observed that consumption
of M. oleifera has no effect on the weight, BMI, and creatinine levels of HIV
patients. It was also observed that the number of participants with nondetectable
viral load in the intervention group increased while that of the control group
decreased. The study concluded that while supplementation with M. oleifera has no
effect on immune functions, hematological parameters, weight, and BMI, it
enhances the efficacy of ARVs in suppressing the viral load of HIV/AIDS patients
and is safe; therefore, nutritional supplementation with M. oleifera should form part
of the strategy to improve treatment outcomes.
Antagonistic Potential of Local Endophytic Fungi Against Root-Knot Nematodes (Meloidogyne Spp.) on Tree Tomato (Solanum Betaceum) In Nyandarua County, Kenya
(Kenyatta University, 2025-11) Waswa,Stanlous Juma
Tree tomato (Solanum betaceum Cav.) is a significant emerging horticultural
cash crop in Kenya with an estimated economic value of over KES 0.5 billion and has
many nutritional and health benefits. Root-knot nematode (RKNs) infestations which
results in significant yield losses, pose a threat to tree tomato growing in Kenya.
Chemical nematicides have been the main method of controlling RKNs. However,
chemical nematicides can be harmful to the environment and human health. Thus, safer
alternatives to current techniques of management are needed. The study's objectives
were: (i) to determine effects of the endophytic fungi associated with tree tomato roots
on second stage juveniles (J2s) of RKN in vitro; (ii) to characterize endophytic fungi
with potential against J2s of RKN; (iii) to ascertain whether Velum® Prime SC 500 (ai =
fluopyram 500g/L) is compatible with endophytic fungi in vitro and under greenhouse
conditions, and (iv) to assess the effectiveness of combining Velum® Prime, Lantana
camara L. leaf extract, and the most effective endophytic fungus (Colletotrichum
nigrum) against RKNs on tree tomatoes in both in vitro and in vivo settings. The
experiments were laid down in completely randomized and randomized complete block
designs in the greenhouse and in the field, respectively, with four replicates per
treatment and terminated 90 days after transplanting. Data on initial and final nematode
populations, total number of RKN J2s, the galling and egg mass indices, the nematode
reproduction factor, height of shoot, and weights of dry roots and shoots were all
recorded. The data were analysed using ANOVA with SAS software version 9.2, and
significant means were separated using Tukey's Honest Significant Difference test at a
5% level (P≤0.05). Regression and correlation analyses were performed to ascertain the
connections between RKN disease parameters. Forty four endophytic fungi isolated
from tree tomato roots belonged to nine genera (Fusarium sp., Colletotrichum sp.,
Aspergillus sp., Penicillium sp., Didymella sp., Periconia sp., Microsphaeropsis sp.,
Rhizoctonia sp. and Purpureocillium sp.). Fusarium sp. (37%) and Purpureocillium sp.
(34%) were most abundant in roots and eggs of RKNs respectively. Colletotrichum
nigrum caused the highest mortality of J2s of 87 % followed by Aspergillus ustus and
Fusarium solani with 63.5% each in-vitro. Velum® Prime did not inhibit colony growth
of C. nigrum on PDA media. Colletotrichum nigrum combined with Velum® Prime
significantly reduced J2s in soil and nematode reproduction factor in the greenhouse
and were therefore compatible. Undiluted Lantana leaf extract + 1 × 106 C. nigrum
caused mortality of J2s with 81% and 83 % in tests I and II, in-vitro. Colletotrichum
nigrum + Lantana leaf extract + Velum® Prime significantly reduced plant disease
parameters (J2s, gall and egg mass indices and nematode reproduction) and also
increased plant growth parameters (shoot height and dry weights) in the greenhouse and
in the field compared to control. New knowledge on integrated nematode management
using endophytic fungi and Lantana leaf extract against second stage juveniles of RKNs
will help farmers in adopting affordable and eco-friendly methods to improve tree
tomato production and increase yield. There is need to commercialize C. nigrum
product and promote use of safe strategies to manage RKNs.