Browsing by Author "Malebo, Hamisi"

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Chitosan-coated liposomes of Carrisa spinarum extract: synthesis, analysis and anti-pneumococcal potency
(ICE Publishing, 2023-02-16) Rubaka, Clarence; Gathirwa, Jeremiah; Malebo, Hamisi; Swai, Hulda; Sibuyi, Nicole; Hilonga, Askwar; Dube, Admire
In the present study, a chitosan (CS)-coated liposome (LipCsP-Chitosan) nanocarrier was fabricated for the delivery of Carissa spinarum (CsP) polyphenols to improve bioavailability and anti-pneumococcal potential against Klebsiella pneumoniae. LipCsP-Chitosan was synthesized by the ion gelation method and characterized by using a Malvern zetasizer and Fourier Transform Infrared (FTIR); CsP encapsulation and release kinetics were investigated. Anti-pneumococcal activity of the nanoformulations was accessed by agar-well diffusion and microdilution assays. LipCsP-chitosan exhibited a hydrodynamic size and zeta potential of 365.22 ± 0.70 nm and +39.30 ± 0.61 mV, respectively. CsP had an encapsulation efficiency of 81.5%. FTIR analysis revealed the interaction of the liposomes with chitosan and the CsP. A biphasic CsP release profile followed by a sustained release pattern was observed. LiPCsP-Chitosan presented a higher bioaccessibility of polyphenols in the simulated gastric phase (74.1% ± 1.3) than in the simulated intestinal phase (63.32% ± 1.00). LipCsP-chitosan had a relative inhibition zone diameter of 84.33% ± 2.51 when compared to CsP. At minimum inhibition concentration of 31.25 mg/mL, LipCsP-Chitosan reduced the viability of Klebsiella pneumoniae by 57.45% ± 3.76 after 24 h. The results obtained from the current study offer a new approach to the utilization of LipCsP-Chitosan as nanocarriers for candidate anti-pneumococcal agents.
Development and Characterization of Nanovesicles Containing Phenolic Compounds of Carissa spinarum: Encapsulation, Release Kinetics, Antimicrobial Activity and Mathematical Modeling
(Trans Tech Publications Ltd, 2023-05) Rubaka, Clarence; Gathirwa, Jeremiah; Malebo, Hamisi; Swai, Hulda; Hilonga, Askwar
The aim of this study was to develop and characterize a delivery system for polyphenols from an extract of Carissa spinarum leaves, based on liposomes. Liposomes loaded with Carissa spinarum polyphenols (nanoliposomal CsP) were prepared by ethanol-solvent injection method and characterized in terms of zeta potential, size, and polydipersity index by using Zeta sizer and Fourier Transform Infrared spectrum analysis. Total Phenolic content was measured by using Folin-Ciocalteu method and entrapment efficiency was evaluated. The release behavior was conducted in Phosphate Buffer Saline (PBS) solution at pH, 7.4 and Kinetic model fitted to evaluate mechanism of release. Disc diffusion sensitivity test was used to evaluate antimicrobial activity of free extract and nanoliposomal CsP. The mean diameter of nanoliposomal CsP was 181 ± 1.02 nm and had 0.345 ± 0.014 polydipersity index. Zeta potential value for nanoliposomal CsP was-45.6 ± 8.84 mV. Entrapment efficiency under the optimum conditions was 66.11 ± 1.11%. and the nanoliposomal CsP was stable over 30 days. The antibacterial activity of nanoliposomal CsP exhibited inhibition zone diameter of 14.33 ± 1.53 mm and 12.00 ± 1.23 mm against S. aureus and E. coli respectively The results reveal the Carrisa spinarum liposome can be applied as potential carrier for delivery of polyphenols to improves therapeutic action against bacterial strain.
Inorganic Nanocarriers: Surface Functionalization, Delivery Utility for Natural Therapeutics - A Review
(Scientific.Net, 2022-08) Rubaka, Clarence; Gathirwa, Jeremiah; Malebo, Hamisi; Swai, Hulda; Hilonga, Askwar
Inorganic nanocarriers for a decade have increased interest in nanotechnology research platform as versatile drug delivery materials. The utility of the inorganic nanocarriers for delivery of therapeutic agents is attributed to their unique properties such as magnetic, photocatalytic nature and the ability to exhibit surface functionalization. Herein, we review the surface functionalization and delivery utility for natural therapeutics exhibited by inorganic nanocarriers mostly focusing on their magnetic, photocatalytic and the plasmonic properties. The review also highlights the influence of electronic property of inorganic surface on functionalization of ligand based natural therapeutic agents. Improvement of stability and therapeutic potential by formation of nanocomposites are detailed. Furthermore, we suggest improvement strategies for stability and toxicity reduction of inorganic nanoparticles that would potentially make them useful for clinical application as therapeutic delivery tools for treatment of various diseases.
Recovery of acetyl cholinesterase inhibition by Methanolic Bark Extract of Acacia nilotica from Organophosphate Pesticides Exposure in mice model
(International Journal of Biosciences, 2020-01-15) Mwezi, Raphael; Machunda, Revocatus; Malebo, Hamisi
Organophosphates (OPs) pesticides are reported to cause acute poisoning because of their ability to inhibit acetyl cholinesterase enzyme (AChE). Available antidotes drugs are atropine sulfur, Pralidoxime (2-pyridine aldoxime methyl chloride) and diazepam, which act to recover OP-AChE inhibition. These are controlled drugs not easily accessed and very expensive. In this present study Acacia nilotica was assessed for its antioxidant activity, and in vivo AChE depression and recovery from OP-AChE inhibition. The mice were exposed in three different OPs including chlorpyrifos 480g/l (CPF), Fenitrothion 10g/l (FNT) and Profenophos 720g/l (PFP). The methanolic bark extract of A. nilotica had a substantial increase of absorbance readings from 2.895±0.0032 to 3.716±0.0259 compared to standard (ascorbic acid) from 0.108±0.0033 to 1.468±0.0297 at P<0.05. AChE depression and recovery were assessed by using the AChE test mate kit to analyze blood collected from the mice’s tail. Recovery effect under crude methanolic extract from A. nilotica, ascorbic acid and normal feeding were compared with the untreated group. Results have shown that there is a significant decrease of AChE level from Day zero to 14th day in all treated groups of CPF, PFP and FNT which indicate poisoning. Significance of AChE recovery observed only in male mice in all treatment groups. This is a first study to assess and report the antioxidant activity of stem bark methanolic extracts of A. nilotica in controlling organophosphate pesticide toxicity in mice, hence further studies on isolation of active compounds are recommended.