Beneficial effects of medicinal plants in fish diseases
- Authors: Stratev, Deyan , Zhelyazkov, Georgi , Noundou, Xavier S , Krause, Rui W M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126177 , vital:35856 , https://doi.org/10.1007/s10499-017-0219-x
- Description: Fish are constantly in contact with pathogens inhabiting water. High populationdensity as well as poor hydrodynamic conditions and feeding lead to an increased sensitivitytowards infections. In order to prevent major economic losses due to diseases, variousmedications are used for treatment and prevention of infections. The use of antimicrobialdrugs in aquacultures could lead to emergence of resistance in pathogenic microorganisms.Alternatives are being sought over the last few years to replace antibiotics, and medicinalplants are one of available options for this purpose. These plants are rich in secondarymetabolites and phytochemical compounds, which have an effect against viral, bacterial, andparasitic diseases in fish. Their main advantage is their natural origin and most of these plantsdo not represent threat for human health, the fish, and the environment. The goal of this reviewis to present information on the treatment of viral, bacterial, and parasitic diseases in fishthrough medicinal plants, with focus on the mechanisms of action of the identified secondarymetabolites, fractions, or plant extracts.
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Biological activities of plant extracts from Ficus elastica and Selaginella vogelli: an antimalarial, antitrypanosomal and cytotoxity evaluation
- Authors: Meyer, Franck , Isaacs, Michelle , Noundou, Xavier S , Krause, Rui W M , Teinkela, J E M , Hoppe, Heinrich C , Mpondo, Albert E M , Azebaze, Anatole G B , Nguemfo, Edwige L , Wintjens, Rene
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126142 , vital:35853 , https://doi.org/10.1016/j.sjbs.2017.07.002
- Description: The cytotoxic, antiplasmodial, and antitrypanosomal activities of two medicinal plants traditionally used in Cameroon were evaluated. Wood of Ficus elastica Roxb. ex Hornem. aerial roots (Moraceae) and Selaginella vogelii Spring (Selaginellaceae) leaves were collected from two different sites in Cameroon. In vitro cell-growth inhibition activities were assessed on methanol extract of plant materials against Plasmodium falciparum strain 3D7 and Trypanosoma brucei brucei, as well as against HeLa human cervical carcinoma cells. Criteria for activity were an IC50 value 10 μg/mL. The extract of S. vogelii did not significantly reduce the viability of P. falciparum at a concentration of 25 μg/mL but dramatically affected the trypanosome growth with an IC50 of 2.4 μg/mL. In contrast, at the same concentration, the extract of F. elastica exhibited plasmodiacidal activity (IC50 value of 9.5 μg/mL) and trypanocidal (IC50 value of 0.9 μg/mL) activity. Both extracts presented low cytotoxic effects on HeLa cancer cell line. These results indicate that the selected medicinal plants could be further investigated for identifying compounds that may be responsible for the observed activities and that may represent new leads in parasitical drug discovery.
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Biological activity of plant extracts and isolated compounds from Alchornea laxiflora: Anti-HIV, antibacterial and cytotoxicity evaluation
- Authors: Ndinteh, Derek T , Olivier, D K , Noundou, Xavier S , Krause, Rui W M , Mnkandhla, D , Isaacs, Michelle , Hoppe, Heinrich C , Muganza, F M , Mbafor, J T , Van Vuuren, S F , Patnala, S
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126634 , vital:35907 , https://doi.org/10.1016/j.sajb.2018.08.010
- Description: This study was designed to assess the cytotoxicity, anti-HIV and antibacterial efficacy of various solvent extracts of roots, stem and leaves of Alchornea laxiflora, as well as five compounds isolated from its methanolic stem extract viz.; ellagic acid (1); 3-O-methyl-ellagic acid (2), 3-O-β-d-glucopyranosyl-β-sitosterol (3), 3-O-acetyl-oleanolic acid (4) and 3-O-acetyl-ursolic acid (5). The tested crude extracts were prepared from several solvent polarities including: hexane (Hex), chloroform (CHCl3), ethyl acetate (EtOAc), ethanol (EtOH), methanol (MeOH) and water (H2O). The anti-HIV properties were assessed on HIV-1 subtype C integrase while the cytotoxicity was tested against Hela cells. The antibacterial activity was studied on a panel of pathogens including gastrointestinal, skin, respiratory and urinary-tract infection causing Gram positive bacteria viz.; Bacillus cereus (ATCC 11778), Enterococcus faecalis (ATCC 29212), Staphylococcus aureus (ATCC 25923) and Staphylococcus saprophyticus (ATCC 15305)] and Gram-negative bacteria, i.e., Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 13883), Moraxella catarrhalis (ATCC 23246). All the tested samples were determined to be non-toxic due to the low inhibitions observed. The most potent anti-HIV activity was observed for the methanolic extract of A. laxiflora root (ALR4) with an IC50 value of 0.21 ng/ml, which was more active than chicoric acid used as reference drug (6.82 nM). Roots, stem and leaves of A. laxiflora extracts exhibited antibacterial activities against most of the Gram-positive bacteria with the minimum inhibitory concentrations (MIC) ranging between 50 and 63 μg/ml. Compounds 1–5 displayed antibacterial activities against S. saprophyticus with MIC values as low as 4 μg/ml. The results inferred from this study demonstrate the potential of A. laxiflora root as a source for new anti-HIV drugs and scientifically validate the traditional use of A. laxiflora in the treatment of gastrointestinal, skin, respiratory and urinary tract related infections. These results reaffirm the ethnopharmacological significance of African traditional medicines.
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Blending problem-based learning and peer-led team learning, in an open ended ‘home-grown’pharmaceutical chemistry case study
- Authors: Sewry, Joyce D , Veale, Clinton G L , Krause, Rui W M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125691 , vital:35809 , https://doi.org/10.1039/C7RP00180K
- Description: Pharmaceutical chemistry, medicinal chemistry and the drug discovery process require experienced practitioners to employ reasoned speculation in generating creative ideas, which can be used to evolve promising molecules into drugs. The ever-evolving world of pharmaceutical chemistry requires university curricula that prepare graduates for their role as designers with the capability of applying complex concepts in pharmaceutical chemistry, thereby improving the decision-making process. Common methods of teaching drug discovery, including the linear nature of the traditional case study model, do not provide a realistic picture of the underlying complexity of the process, nor do they equip students with the appropriate tools for personal sense making and abstraction. In this work, we discuss the creation of an open-ended, nonlinear case study for 3rd year pharmaceutical chemistry students, developed from drug discovery research conducted at Rhodes University. Furthermore, we discuss blending problem based learning (PBL) with peer-led team learning (PLTL) in the context of curriculum transformation, underpinned by the theory of semantic waves, to assist students in the early attainment of abstract concepts and answer questions of contextualisation, personal sense making, relatability, relevance and ultimately the skills for lifelong learning.
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Conjugation of isoniazid to a zinc phthalocyanine via hydrazone linkage for pH-dependent liposomal controlled release
- Authors: Nkanga, Christian , Krause, Rui W M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/194992 , vital:45517 , xlink:href="https://doi.org/10.1007/s13204-018-0776-y"
- Description: Tuberculosis (TB) remains the leading cause of mortality from infectious diseases. Extended TB treatment and frequent adverse effects, due to poor bioavailability of anti-tubercular drugs (ATBDs), represent the main rationales behind liposomal encapsulation for controlled delivery. Liposomes have been reported as potential vehicles for targeted delivery of ATBDs due to their rapid uptake by macrophages, which are known as the main host cells for TB causative agent (Mycobacterium tuberculosis). Additionally, the need for controlled release of ATBDs arises because leakage is part of the key liposome challenges for hydrophilic compounds like isoniazid (INH). In this study, INH was conjugated to a highly hydrophobic photosensitizer, zinc (II) phthalocyanine (PC), through hydrazone bonding. The obtained conjugate (PC–INH) was encapsulated in liposomes by film hydration method. PC–INH loaded liposomes (PILs) were characterized using dynamic light scattering, transmission electron microscopy, energy-dispersive X-ray spectrometry and UV–Vis absorption spectrometry, which was used also for estimation of encapsulation efficiency (%EE). INH release was evaluated in different pH media using dialysis. Particle size, zeta potential and %EE of PILs were about 506 nm, − 55 mV and 72%, respectively. Over 12 h, PILs exhibited 22, 41, 97 and 100% of INH, respectively, released in pH 7.4, 6.4, 5.4 and 4.4 media. This pH-dependent behavior is attractive for site-specific delivery. These findings suggest the conjugation of chemotherapeutics to phthalocyanines using pH-labile linkages as a potential strategy for liposomal controlled release.
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Current trend in synthesis, Post-Synthetic modifications and biological applications of Nanometal-Organic frameworks (NMOFs)
- Authors: Baa, Ebenezer , Watkins, Gary M , Krause, Rui W M , Tantoh, Derek N
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127042 , vital:35946 , https://doi.org/10.1002/cjoc.201800407
- Description: Since the early reports of MOFs and their interesting properties, research involving these materials has grown wide in scope and applications. Various synthetic approaches have ensued in view of obtaining materials with optimised properties, the extensive scope of application spanning from energy, gas sorption, catalysis biological applications has meant exponentially evolved over the years. The far‐reaching synthetic and PSM approaches and porosity control possibilities have continued to serve as a motivation for research on these materials. With respect to the biological applications, MOFs have shown promise as good candidates in applications involving drug delivery, BioMOFs, sensing, imaging amongst others. Despite being a while away from successful entry into the market, observed results in sensing, drug delivery, and imaging put these materials on the spot light as candidates poised to usher in a revolution in biology. In this regard, this review article focuses current approaches in synthesis, post functionalization and biological applications of these materials with particular attention on drug delivery, imaging, sensing and BioMOFs.
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In vitro antimalarial, antitrypanosomal and HIV-1 integrase inhibitory activities of two Cameroonian medicinal plants: Antrocaryon klaineanum (Anacardiaceae) and Diospyros conocarpa (Ebenaceae)
- Authors: Fouokeng, Y , Feusso, H M Feumo , Noundou, Xavier S , Krause, Rui W M , Teinkela, Jean E Mb , Wintjens, R , Hoppe, Heinrich C , Azebaze, Anatole G B , Vardamides, Juliette C , Isaacs, Michelle
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126653 , vital:35908 , https://doi.org/10.1016/j.sajb.2018.10.008
- Description: Antiplasmodial, antitrypanosomal and anti-HIV-1 activities of crude extracts, fractions and some isolated compounds from two Cameroonian medicinal plants: Antrocaryon klaineanum Pierre (Anacardiaceae) and Diospyros conocarpa Gürke ex K. Schum. (Ebenaceae) were assessed. The phytochemical studies led to the isolation of eight compounds (1–8) from Diospyros conocarpa and six compounds (6, 9–13) from Antrocaryon klaineanum. These compounds were identified as mangiferolic acid (1), 3β, 22(S)-dihydroxycycloart-24E-en-26-oic acid (2), lupeol (3), aridanin (4), betulin (5), betulinic acid (6), bergenin (7), D-quercitol(8), entilin C(9), entilin A(10), antrocarine A(11), 7R,20(S)-dihydroxy-4,24(28)-ergostadien-3-one(12) and stigmasterol glucoside (13). The criteria for activity were set as follows: an IC50 value
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Isolation and Characterisation of Stigmasterol and β–Sitosterol from Anthocleista djalonensis A. Chev.
- Authors: Okoro, Ijeoma S , Tor-Anyiin, Terrumun A , Igoli, John O , Noundou, Xavier S , Krause, Rui W M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126191 , vital:35857 , https://doi.org/10.9734/AJOCS/2017/37147
- Description: Aim: Anthocleista djalonensis A. Chev. is a plant with several chemical constituents whichaccounts for its ethno-pharmacological uses. The present study is aimed at identifying and characterizing the active principles from the roots of the plant. Place and Duration of Study: The study was carried out at the Department of Organic Chemistry,Rhodes University, Grahamstown, South Africa between March and July 2016. Methodology: The root powder was subjected to maceration with methanol to obtain the crude extract. The methanol extract was fractionated using hexane, ethyl acetate and acetone successively. The acetone extract was thereafter subjected to column chromatography to isolate any pure components. Results: White needle-like crystals were obtained which on spectral analysis(IR, 1H NMR, 13C NMR, 2D- NMR, and ESI-MS ) were identified as a mixture of stigmasterol and β-sitosterol. Conclusion: The compounds isolated were identified as stigmasterol and β-sitosterol.
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pH-Dependent release of isoniazid from isonicotinic acid (4-hydroxy-benzylidene)-hydrazide loaded liposomes
- Authors: Nkanga, Christian I , Tor-Anyiin, Terrumun A , Igoli, John O , Noundou, Xavier S , Krause, Rui W M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126427 , vital:35884 , https://doi.org/10.9734/AJOCS/2017/37147
- Description: Liposomes are considered as potential vehicles for the delivery of anti-tuberculosis drugs (ATBD) due to their rapid uptake by alveolar macrophages, where the mycobacterium often resides. This may provide macrophage-targeting effects that would be key to site specific ATBD delivery using pH-sensitive liposomes, considering the pH-gradient found in the phagocytotic pathway. In this study, isoniazid (INH) was conjugated to 4-hydroxy-benzaldehyde via a hydrazone bond to yield isonicotinic acid (4-hydroxy-benzylidene)-hydrazide (INH-HB). This conjugate was encapsulated in crude soybean lecithin liposomes using film hydration method. INH-HB loaded liposomes (IHL) were characterized by means of dynamic light scattering, transmission electron microscopy, differential scanning calorimetry and X-ray diffraction. The release of INH from IHL was evaluated in media of different pH using a dialysis method. The particle size, Zeta Potential and encapsulation efficiency of IHL were about 945 nm, −62 mV and 89% respectively. In media of pH 7.4, 6.4, 5.4 and 4.4; the IHL exhibited respectively 22, 69, 83 and 100% of release over 12 h. In addition to possible targeted delivery, this pH-dependent release behavior may be suitable for minimizing the loss of INH by leakage from liposomes. The characteristics of IHL are promising for potential site-specific delivery of ATBD.
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Synthesis, antiplasmodial and antitrypanosomal evaluation of a series of novel 2-oxoquinoline-based thiosemicarbazone derivatives
- Authors: Darrell, Oliver T , Hulushe, Siyabonga T , Mtshare, Thanduxolo Elihle , Beteck, Richard M , Isaacs, Michelle , Laming, Dustin , Khanye, Setshaba D , Hoppe, Heinrich C , Krause, Rui W M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123117 , vital:35407 , https://doi.org/10.17159/0379-4350/2018/v71a25
- Description: Herein a series of novel thiosemicarbazones (TSCs) derived from 2-oxoquinoline scaffold is reported, and the target compounds have been successfully synthesized and characterized using standard spectroscopic techniques. The in vitro biological activities of synthesized molecules were evaluated against Plasmodium falciparum malaria parasites (strain 3D7), Trypanosoma brucei brucei parasites (strain 427) and HeLa cells. All the compounds displayed modest or no activity at a concentration of 20 μM and percentage viability of >50 % was often observed. Except for compound 9o, none of the final compounds exhibited cytotoxic effects against HeLa cells at 20 μM.
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Three new pentacyclic triterpenoids from twigs of Manniophyton fulvum (Euphorbiaceae)
- Authors: Mbeunkeu, Ahri B D , Noundou, Xavier S , Krause, Rui W M , Teinkela, Jean E M , Laatsch, Hartmut , Azebaze, Anatole G B , Vardamides, Juliette C , Tala, Michel F
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126782 , vital:35922 , https://doi.org/10.1016/j.phytol.2018.06.019
- Description: Phytochemical investigation of the methanol extracts of the twigs of Manniophyton fulvum has led to the isolation and characterization of three new pentacyclic triterpenoids, designated as 3α,28-dihydroxyfriedelan-1-one (1), manniotaraxerol A (3) and manniotaraxerol B (4), along with fourteen known compounds, 3α-hydroxy-1-oxofriedelane (2), betulinic acid (5), friedelin (S1), taraxerol (S2), a mixture of stigmasterol (S3) and β-sitosterol (S4), herranone (S5), docosanoic acid (S6), ursolic acid (S7), nasutin B (S8), bergenin (S9), stigmasterol-3-O-β-Dglucopyranoside (S10), 1,2-di-O-palmitoyl-3-O-(6-sulfo-α-D-quinovopyranosyl)glycerol (S11), and aridanin (S12). The structures of all compounds were determined by comprehensive spectroscopic analyses (1D and 2D NMR, EI and ESI-MS). 3α,28-Dihydroxyfriedelan-1-one (1), 3α-hydroxy-1-oxofriedelane (2), manniotaraxerol A (3), manniotaraxerol B (4), and betulinic acid (5) were evaluated against HeLa (human cervix adenocarcinoma) cancer cells. Manniotaraxerol A (3) showed weak in vitro cytotoxicity with a cell viability value of 49.3%. Betulinic acid (5) also showed significant cytotoxicity against HeLa cell with a cell viability value of 4.0%; the other compounds were inactive in this test.
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Beneficial effects of medicinal plants in fish diseases
- Authors: Stratev, Deyan , Zhelyazkov, Georgi , Noundou, Xavier Siwe , Krause, Rui W M
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123487 , vital:35447 , https://doi.org/10.1007/s10499-017-0219-x
- Description: Fish are constantly in contact with pathogens inhabiting water. High population density as well as poor hydrodynamic conditions and feeding lead to an increased sensitivity towards infections. In order to prevent major economic losses due to diseases, various medications are used for treatment and prevention of infections. The use of antimicrobial drugs in aquacultures could lead to emergence of resistance in pathogenic microorganisms. Alternatives are being sought over the last few years to replace antibiotics, and medicinal plants are one of available options for this purpose. These plants are rich in secondary metabolites and phytochemical compounds, which have an effect against viral, bacterial, and parasitic diseases in fish. Their main advantage is their natural origin and most of these plants do not represent threat for human health, the fish, and the environment. The goal of this review is to present information on the treatment of viral, bacterial, and parasitic diseases in fish through medicinal plants, with focus on the mechanisms of action of the identified secondary metabolites, fractions, or plant extracts.
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