Felix Muema

Mr. Felix Muema


Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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19 February 2023 in Pharmaceutics
Verified
Journal Article
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Tojofaniry Fabien RakotondrabeTojofaniry Fabien Rakotondrabe
Tojofaniry Fabien Rakotondrabe
Minxia FanMinxia Fan
Minxia Fan
FMFelix Muema
Felix Muema
MGMingquan Guo
Mingquan Guo
The global increase and prevalence of inflammatory-mediated diseases have been a great menace to human welfare. Several works have demonstrated the anti-inflammatory potentials of natural polyphenolic compounds, including flavonoid derivatives (EGCG, rutin, apigenin, naringenin) and phenolic acids (GA, CA, etc.), among others (resveratrol, curcumin, etc.). In order to improve the stability and bioavailability of these natural polyphenolic compounds, their recent loading applications in both organic (liposomes, micelles, dendrimers, etc.) and inorganic (mesoporous silica, heavy metals, etc.) nanocarrier technologies are being employed. A great number of studies have highlighted that, apart from improving their stability and bioavailability, nanocarrier systems also enhance their target delivery, while reducing drug toxicity and adverse effects. This review article, therefore, covers the recent advances in the drug delivery of anti-inflammatory agents loaded with natural polyphenolics by the application of both organic and inorganic nanocarriers. Even though nanocarrier technology offers a variety of possible anti-inflammatory advantages to naturally occurring polyphenols, the complexes’ inherent properties and mechanisms of action have not yet been fully investigated. Thus, expanding the quest on novel natural polyphenolic-loaded delivery systems, together with the optimization of complexes’ activity toward inflammation, will be a new direction of future efforts.

15 March 2021 in Pharmaceuticals
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Journal Article
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Moses MutungiMoses Mutungi
Moses Mutungi
FMFelix Muema
Felix Muema
FKFestus Kimutai
Festus Kimutai
XYXu Yongbing
Xu Yongbing
HZhui zhang
hui zhang
MGMingquan Guo
Mingquan Guo
Ficus glumosa Delile (Moraceae), a reputed plant that is used in herbal medicine, is of high medicinal and nutritional value in local communities primarily ascribed to its phytochemical profile. Currently, there are hardly any fine details on the chemical profiling and pharmacological evaluation of this species. In this study, the flavonoids and phenolics contents of the ethanol extracts and four extracted fractions (petroleum ether (PE), ethyl acetate (EA), n-butanol, and water) of the stem bark of Ficus glumosa were firstly quantified. Further, their antioxidant and antiproliferative potentials were also evaluated. The quantitative determination indicated that the EA and n-butanol fractions possessed the highest total flavonoids/phenolics levels of 274.05 ± 0.68 mg RE/g and 78.87 ± 0.97 mg GAE/g, respectively. Similarly, for the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and ferric-reducing antioxidant power (FRAP) assays, the EA fraction exhibited high potency in both DPPH and ABTS+ scavenging activities with IC50 values of 0.23 ± 0.03 mg/mL, 0.22 ± 0.03 mg/mL, and FRAP potential of 2.81 ± 0.01 mg Fe2+/g, respectively. Furthermore, the EA fraction displayed high cytotoxicity against human lung (A549) and colon (HT-29) cancer cells. Additionally, the liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) was employed in order to characterize the chemical constituents of the EA fraction of Ficus glumosa stem bark. Our findings revealed 16 compounds from the EA fraction that were possibly responsible for the strong antioxidant and anti-proliferative properties. This study provides edge-cutting background information on the exploitation of Ficus glumosa as a potential natural antioxidant and anti-cancer remedy.

17 June 2022 in Antioxidants
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Journal Article
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FMFelix Muema
Felix Muema
YLYe Liu
Ye Liu
YZYongli Zhang
Yongli Zhang
GCGuilin Chen
Guilin Chen
MGMingquan Guo
Mingquan Guo
Selaginella doederleinii Hieron. (S. doederleinii) is a traditional herb that is widely used in China to treat several ailments, but mainly cancer. Studies have been carried out to determine the phytochemicals ascribed to its pharmacological activity. However, both phytochemical and pharmacological profiles have not been fully explored as few compounds have been reported. This study evaluated the flavonoid content of the ethanol extract and its four fractions (petroleum ether, dichloromethane, ethyl acetate, and n-butanol) together with their antioxidant activity (DPPH and FRAP assays). Further, the antiproliferative activity was evaluated. Two new secondary metabolites (1 and 3) were isolated from S. doederleinii, which comprised of an apigenin skeleton with a phenyl attached at C-8 of ring A and an acetyl group. Additionally, other known metabolites 2 and 4–16 were isolated, whereby compounds 2, 4, 5, 8, 12, 15, and 16 were reported for the first time in this species. These compounds were evaluated for their antioxidative potentials by both DPPH and FRAP assays, and for their antiproliferative activities by the MTT assay on three human cancer cell lines: colon cancer (HT-29), cervical cancer (HeLa), and lung cancer (A549). Compound 7 exhibited the best activity on the three cancer cell lines (HT-29, HeLa, A549) by inhibiting the rate of growth of the cancer cells in a dose-dependent manner with IC50 values of 27.97, 35.47, and 20.71 µM, respectively. The structure–activity relationship of the pure compounds was highlighted in this study. Hence, the study enriched both the phytochemical and pharmacological profiles of S. doederleinii.

23 April 2021 in Antioxidants
Verified
Journal Article
Open access
PDF file
YLYe Liu
Ye Liu
YZYongli Zhang
Yongli Zhang
FMFelix Muema
Felix Muema
FKFestus Kimutai
Festus Kimutai
GCGuilin Chen
Guilin Chen
MGMingquan Guo
Mingquan Guo
Carissa spinarum has been traditionally used for the treatment of various diseases due to its different pharmacological activities. However, the active compounds responsible for its potentially specific activities have rarely been explored. To this end, the ethyl acetate (EA) fraction was screened out and selected for further phytochemical isolation because of its promising activities in preliminary 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and COX-2 inhibition assays. As a result, 10 compounds (1−10), including a new one (5), were isolated, with eight of these being identified as phenolic compounds, as expected. Compound 9 possessed an IC50 value of 16.5 ± 1.2 µM, which was lower than that of positive control (vitamin C, 25.5 ± 0.3 µM) in the DPPH assay, and compounds 2, 6, 7 and 9 showed better total antioxidant capacity than vitamin C in the FRAP assay. Meanwhile, compounds 1−6 and 9 also had IC50 values of less than 1.0 µM, which was even better than the positive control indomethacin in the COX-2 inhibition assay. In this context, compounds 2 and 9 were further evaluated to exhibit clear hepatoprotective activities by improving the L02 cell viability and reducing ROS production using a H2O2-induced L02 cell injury model. This study provides initial evidence revealing the most potent phenolic compounds from the root bark of C. spinarum responsible for its antioxidant, anti-inflammatory and hepatoprotective activities.

18 August 2021 in Antioxidants
Verified
Journal Article
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YLYe Liu
Ye Liu
FMFelix Muema
Felix Muema
YZYongli Zhang
Yongli Zhang
MGMingquan Guo
Mingquan Guo
Carissa spinarum Linn. has been utilized both in the food industry and as a traditional medicine for various ailments, while the responsible chemical components and action mechanisms of its antioxidative and hepatoprotective activities remain unclear. In this work, at least 17 quinic acid derivatives as potential ligands for the superoxide dismutase (SOD) enzyme from Carissa spinarum L. were screened out using the bio-affinity ultrafiltration with liquid chromatography mass spectrometry (UF–LC/MS), and 12 of them (1–12), including, three new ones (1–3), were further isolated by phytochemical methods and identified by high resolution electrospray ionization mass spectrometry (HR-ESI-MS) and extensive nuclear magnetic resonance (NMR) spectroscopic analysis. All of these isolated compounds were evaluated for their antioxidant activities by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric-reducing antioxidant power (FRAP) methods. As a result, compounds 4 and 6–11 displayed similar or better antioxidant activities compared to vitamin C, which is in good agreement with the bio-affinity ultrafiltration with SOD enzyme. Then, these compounds, 4 and 6–11, with better antioxidant activity were further explored to protect the L02 cells from H2O2-induced oxidative injury by reducing the reactive oxygen species (ROS) and Malondialdehyde (MDA) production and activating the SOD enzyme. To the best of our knowledge, this is the first report to use an efficient ultrafiltration approach with SOD for the rapid screening and identification of the SOD ligands directly from a complex crude extract of Carissa spinarum, and to reveal its corresponding active compounds with good antioxidative and hepatoprotective activities.

21 July 2022 in Pharmaceuticals
Verified
Journal Article
Open access
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Emmanuel WaswaEmmanuel Waswa
Emmanuel Waswa
FMFelix Muema
Felix Muema
WOwyclif Ochieng odago
wyclif Ochieng odago
Elizabeth MutindaElizabeth Mutinda
Elizabeth Mutinda
CNConsolata Nanjala
Consolata Nanjala
Guangwan HuGuangwan Hu
Guangwan Hu
Blechnum L. is a genus belonging to the Blechnaceae family with 236 accepted species that grow in intertropical, subtropical, and southern temperate regions. Several species of the genus have long been used in folk medicines to treat a broad spectrum of ailments, including typhoid, urinary infections, influenza, wounds, pulmonary complaints, blisters, boils, and antihelmintic-related complications. So far, about 91 chemical compounds have been isolated from different parts of 20 Blechnum species. Among these metabolites, phenolic compounds, sterols, and fatty acids are the main constituents. Modern pharmacological investigations revealed several isolated compounds and extracts to exhibit exceptional biological properties including the antioxidant, antimicrobial, anti-inflammatory, anticancer, insecticidal, antitrematocidal and wound healing. In various tests, both quercetin-7′,3′,4′-trimethoxy and phytol metabolites showed potential antioxidant and antitrematocidal properties, while ponasterone exhibited insecticidal activity. Despite having a broad range of traditional medicinal benefits and biological properties, understanding the scientific connotations based on the available data is still challenging. This article presents a comprehensive review of the traditional uses, phytochemical compounds, and pharmacological aspects of the Blechnum species.