Browsing by Author "Omonike, O. Ogbole"

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    Evaluation of multifunctional activity of bioactive peptide fractions from the leaves of Nauclea diderrichii (De Wild. and T. Durand) Merrill and Ixora brachypoda DC
    (Elsevier B.V., 2021-02) Omonike, O. Ogbole; Abraham, Nkumah; Toluwanimi, E. Akinleye; Fredrick, E. Olisaedu; Alfred, F. Attah
    Bioactive peptides are known for health-promoting properties due to several pharmacological effects they modulate in physiological systems. Herein, the presence of peptides particularly cyclic peptides, was investigated in two Rubiaceae members; Nauclea diderichii (De Wild. and T. Durand) Merrill and Ixora brachypoda DC by thin layer chromatography (TLC) chemical detection, and their multifunctional bioactivity evaluated. Crude and pre-purified peptides were obtained from both plants using aqueous and solid-phase extractions, respectively. The peptide fraction of N. diderrichii showed good DPPH scavenging activity (IC50 = 3.43 μg/mL) compared to the standard Gallic acid (IC50 = 1.44 μg/mL). Peptide fractions of both plants displayed inhibitory effects (MIC = 6.25 μg/mL) against bacteria and fungi strains except Escherichia coli, relative to standard drugs (MIC = 0.31 μg/mL). Both displayed significant toxicity to brine shrimp nauplii (LC50≤ 220.8 μgmL-1) as well as MCF-7 and RD cancer cells (IC50 ≤ 34.0 μgmL-1). The enterovirus species B and C tested were remarkably susceptible to the peptide fractions (IC50 ≤ 3.20 μg/mL).
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    Evaluation of peptide-rich root extracts of Calliandria portoriscensis (Jacq.) Benth (Mimosaceae) for in vitro antimicrobial activity and brine shrimp lethality
    (BMC Complementary Medicine and Therapies, 2020-02-03) Omonike, O. Ogbole; Nkiruka, C. Ndabai; Toluwanimi, E. Akinleye; Alfred, F. Attah
    Background Several Host defence peptides (HDPs) are low molecular weight (< 50 amino acids residues) peptides detected in several ethnomedicinal plants and have particularly gained research interest in recent times. Due to their wide range of bioactivity, occurrence, abundance and ability to induce very little resistance, they hold promising potentials in drug development. This study investigated the presence of bioactive peptides in the roots of Calliandra portoricensis (CPr) (Mimosaceae) and evaluated its antimicrobial activity against gram-negative and gram-positive bacteria. Methods The crude peptide extract was obtained and pre-purified on pre-loaded tube of RP-C18 solid phase cartridges (strata giga tube C18-E; 5 g, 20 mL, Phenomenex, Germany). Peptide enriched fraction was chemically analysed for arginine-rich/aromatic amino acid-rich peptides using a modified G-250 analytical stain and ninhydrin on thin layer chromatography (TLC) for a preliminary screening. Furthermore, MALDI TOF/TOF peptidomics was used to detect the presence and masses of the peptides. Extracts from CPr were used to test the ability to inhibit microbial growth using p-INT (Para-iodonitrotetrazolium violet) dye, with 0.1% gentamycin as positive control. The concentration that inhibits the growth of microorganisms by 50% (IC50) were determined. Toxicity of the two extracts was accessed using freshly hatched nauplii of Artemia salina. Data analysis were evaluated using Microsoft excel and GraphPad Prism5. Results Low molecular weight (LMW) peptides were detected in CPr using TLC and MALDI-TOF MS. Generally, the extracts exhibited good inhibition (70–95%) against the gram-negative and gram-positive bacteria, except MRSA6 typed strain. Enhanced activity was observed in the pre-purified peptide fraction than in the methanol crude, except on MRSA6. The greatest antimicrobial inhibition by pre-purified peptide fraction was against MRSA22 (IC50 = 0.69 ± 0.33 μg/mL). The crude methanol extract (LC50 = 5.13 μg/mL) was slightly more toxic than the peptide extract (LC50 = 6.12 μg/mL). Conclusions This is the first report on detection of bioactive LMW peptides in Mimosaceae family. These peptides appear to be rich in arginine and aromatic amino acids. The peptide extract, in its pre-purified form showed a lower Brine shrimp cytotoxicity and an enhanced antimicrobial activity against the tested gram-negative and gram-positive bacteria.
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    In vitro antiviral activity of peptide‑rich extracts from seven Nigerian plants against three non‑polio enterovirus species C serotypes
    (Virology Journal, 2021) Omonike, O. Ogbole; Toluwanimi, E. Akinleye; Abraham, O. Nkumah; Aminat, O. Awogun; Alfred, F. Attah; Moses, O. Adewumi; Adekunle, J. Adeniji
    Background: As frequent viral outbreaks continue to pose threat to public health, the unavailability of antiviral drugs and challenges associated with vaccine development underscore the need for antiviral drugs discovery in emergent moments (endemic or pandemic). Plants in response to microbial and pest attacks are able to produce defence molecules such as antimicrobial peptides as components of their innate immunity, which can be explored for viral therapeutics. Methods: In this study, partially purified peptide-rich fraction (P-PPf ) were obtained from aqueous extracts of seven plants by reverse-phase solid-phase extraction and cysteine-rich peptides detected by a modified TLC method. The peptide-enriched fractions and the aqueous (crude polar) were screened for antiviral effect against three non-polio enterovirus species C members using cytopathic effect reduction assay. Results: In this study, peptide fraction obtained from Euphorbia hirta leaf showed most potent antiviral effect against Coxsackievirus A13, Coxsackievirus A20, and Enterovirus C99 (EV-C99) with IC50 < 2.0 μg/mL and selective index ≥ 81. EV-C99 was susceptible to all partially purified peptide fractions except Allamanda blanchetii leaf. Conclusion: These findings establish the antiviral potentials of plants antimicrobial peptides and provides evidence for the anti-infective use of E. hirta in ethnomedicine. This study provides basis for further scientific investigation geared towards the isolation, characterization and mechanistic pharmacological study of the detected cysteine-rich peptides.