Browsing by Author "Christine, Kyarimpa"

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Lacustrine cyanobacteria, algal blooms and cyanotoxins in east Africa: implications for human and ecological health protection
(Phycology, 2023-02) Timothy, Omara; Christine, Betty Nagawa; Christine, Kyarimpa; Stefan, Böhmdorfer; Thomas, Rosenau; Solomon, Omwoma Lugasi; Henry, Matovu; Silver, Odongo; Patrick, Ssebugere
Advected cyanobacteria, algal blooms and cyanotoxins have been increasingly detected in freshwater ecosystems. This review gives an insight into the present state of knowledge on the taxonomy, dynamics, toxic effects, human and ecological health implications of cyanobacteria, algal blooms and cyanotoxins in the East African Community lakes. The major toxigenic microalgae in East African lakes include Microcystis, Arthrospira, Dolichospermum, Planktolyngbya and Anabaenopsis species. Anatoxin-a, homoanatoxin-a, microcystins (MCs), cylindrospermopsin and nodularin have been quantified in water from below method detection limits to 81 μg L−1, with peak concentrations characteristically reported for the wet season. In whole fish, gut, liver and muscles, MCs have been found at concentrations of 2.4 to 1479.24 μg kg−1, which can pose human health risks to a daily consumer. While there have been no reported cases of cyanotoxin-related poisoning in humans, MCs and anatoxin-a (up to 0.0514 μg kg−1) have been identified as the proximal cause of indiscriminate fish kills and epornitic mortality of algivorous Phoeniconaias minor (lesser flamingos). With the unequivocal increase in climate change and variability, algal blooms and cyanotoxins will increase in frequency and severity, and this will necessitate swift action towards the mitigation of nutrient-rich pollutants loading into lakes in the region.
Medicinal plants used in the management of sexual dysfunction, infertility and improving virility in the east African community: a systematic review
(Evidence-Based Complementary and Alternative Medicine, 2023-08) Christine, Kyarimpa; Christine, Betty Nagawa; Timothy, Omara; Silver, Odongo; Patrick, Ssebugere; Solomon, Omwoma Lugasi; Ivan, Gumula
Sexual disorders such as erectile dysfunction (ED), sterility, and sexual inappetence represent some of the complex reproductive challenges that require addressing the underlying causes. Te aim of this paper was to systematically synthesize literature on the ethnobotany, phytochemistry, bioactivities, and safety of plants used as remedies for managing sexual dysfunction and infertility, and improving fertility and virility in the EAC. Trough an extensive review conducted in multidisciplinary electronic databases, 171 plant species were identifed to have been reported for the management of sexual inappetence (i.e., used as aphrodisiacs, 39.4%), ED (35.9%), infertility (18.7%), and increasing fertility (6.0%). Te most used plants are Mondia whitei, Acalypha villicaulis, Combretum illairii, Erythrina abyssinica, Pappea capensis, Rhus vulgaris, and Warburgia ugandensis while roots (44.9%), leaves (21.8%), stem and root barks (16.7%) of shrubs (35%), trees (31%), herbs (26%), and climbers (8%) are the preferred organs for making decoctions (69%). Te research strides to date indicate that Citropsis articulata, Cola acuminata, Ekebergia capensis, Plumbago zeylanica, Tarenna graveolens, Urtica massaica, and Zingiber ofcinale have been assessed for their bioactivity. Te majority (71.4%) of the plants either increased testosterone levels and mounting frequency or elicited prosexual stimulatory efects in male rats. More studies investigating the relevant pharmacological activities (aphrodisiac, fertility, and phosphodiesterase-5 inhibitory activities), safety aspects, responsible compounds, and clinical studies are warranted to establish the pharmacological potential of the unstudied species and elucidate the mechanism of action of the bioactive compounds.
Sorption mechanisms and enhancement of selected organochlorine pollutants in water on zeolites
(Journal of Chemistry, 2024-01) Timothy, Manda; Solomon, Omwoma; Godfrey, Okumu Barasa; Anthony, M. Pembere; Douglas, Sifuna; Livingstone, Ochilo; Silas, Lagat; Emily, Ngeno; Patrick, Ssebugere; Christine, Betty Nagawa; Christine, Kyarimpa
Tis study investigates the adsorption capacities of selected organochlorines on zeolites, focusing on hexachlorobenzene (HCB), hexachlorotetradecane (HCTD), hexachlorodecane (HCD), hexachlorocyclohexane (HCH), heptachlorodecane (HPCD), octachlorodecane (OCD), dichlorodiphenyltrichloroethane (DDT), and octachlorotetradecane (OCTD). Te structures of the organochlorines were optimized and their Frontier molecular orbitals were calculated. Te analysis of HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energies provided insights into the molecules’ electron-donating and -accepting capabilities. Te present research identifed the universal force feld as suitable for the investigation and used it to evaluate the adsorption capacities of the pollutants on various zeolites. It was found that CLO (a cubic microporous gallophosphate) demonstrated the highest adsorption capacity for HCB among 245 zeolites, with a loading capacity of 65.84 wt%. In terms of molecules adsorbed per cell, CLO remained the highest with 120 molecules per cell for HCB, 113 molecules per cell for HCH, 43 molecules per cell for DDT, 21 molecules per cell for HCTD, 19 molecules per cell for OCTD, 47 molecules per cell for HCD, 30 molecules per cell for HPCD, and 22 molecules per cell for OCD. Te analysis revealed correlations between the structural parameters of zeolites (mass, density, HVF, APV, VSA, GSA, DPS, and Di) and their adsorption capacities. Te investigation delved into cluster models to understand the interaction of organochlorines with the zeolite framework. Te study explored the impact of doping CLO zeolite with diferent atoms (Al, Si, and Na) on adsorption capacity. Te results showed that doping with aluminum improved both loading capacity and adsorption energy and dissociate the chlorinated compounds during adsorption. Quantum chemical calculations show that hydrogen-based bonding of the organochlorides on the CLO is thermodynamically favorable compared to dissociative adsorption. In addition, oxygen atoms in the zeolites provide active adsorption sites. In the present work, laboratory adsorption experiments were performed, treating zeolites with heat at 400 °C. Surprisingly, untreated zeolites outperformed treated ones, adsorbing up to 91% of HCB, while treated zeolites reached saturation after the third run. Te study attributed the better performance of untreated zeolites to the presence of interstitial water and hydrogen atoms, which are critical for electrostatic interactions with organic compounds. In general, this research provides a comprehensive analysis of the adsorption capacities of organochlorines on zeolites, combining computational simulations and laboratory experiments. Tis work’s distinctive quality is its methodology that combines molecular simulations, experimental verifcation, doping, and interstitial water efects. Te fndings emphasize the importance of zeolite (a high-porosity nanostructured material) structure, composition, and treatment methods in determining their efectiveness as adsorbents for environmental pollutants.