Browsing by Author "Osei-Safo, D."

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Analgesic effects of a hydro-ethanolic whole plant extract of Synedrella nodiflora (L.) Gaertn in paclitaxel-induced neuropathic pain in rats
(BioMed Central Ltd., 2017) Amoateng, P.; Adjei, S.; Osei-Safo, D.; Kukuia, K.K.E.; Kretchy, I.A.; Sarkodie, J.A.; N'Guessan, B.B.
Background: Synedrella nodiflora is used by traditional healers in Ghana for the management of epilepsy and pain. The hydro-ethanolic extract of the whole plant has demonstrated antinociceptive effect in various animal models of pain. This study investigated the potential benefit of the hydro-ethanolic extract in a rat model of paclitaxel-induced neuropathic pain. Methods: Neuropathy was induced in rats by a continuous intraperitoneal administration of paclitaxel (2 mg/kg) for 5 days. Baseline latencies to thermal pain were recorded before the first injection of paclitaxel and during the 5 day induction period. Following the induction, the rats in designated treatment group were treated with the hydro-ethanolic extract (100, 300 and 1000 mg/kg, p.o) or pregabalin (10, 30 and 100 mg/kg) or vehicle (distilled water) and their responses to thermal hyperalgesia measured every 30 for a total period of 3 h. Results: There was a significant difference between the baseline reaction latency and what was observed on the 5th day of the induction of neuropathy. Two days after the induction of neuropathy, the extract and pregabalin significantly and dose-dependently produced antinociceptive effect during the 3-h test period. Conclusion: The hydro-ethanolic extract of the whole plant of Synedrella nodiflora possess analgesic effect in paclitaxel-induced neuropathy in rats.
Antischistosomal, antionchocercal and antitrypanosomal potentials of some Ghanaian traditional medicines and their constituents
(PLOS, 2020) Osei-Safo, D.; Twumasi, E.B.; Akazue, P.I.
Background Ghana is endemic for some neglected tropical diseases (NTDs) including schistosomiasis, onchocerciasis and lymphatic filariasis. The major intervention for these diseases is mass drug administration of a few repeatedly recycled drugs which is a cause for major concern due to reduced efficacy of the drugs and the emergence of drug resistance. Evidently, new treatments are needed urgently. Medicinal plants, on the other hand, have a reputable his- tory as important sources of potent therapeutic agents in the treatment of various diseases among African populations, Ghana inclusively, and provide very useful starting points for the discovery of much-needed new or alternative drugs. Methodology/Principal findings In this study, extracts of fifteen traditional medicines used for treating various NTDs in local communities were screened in vitro for efficacy against schistosomiasis, onchocerciasis and African trypanosomiasis. Two extracts, NTD-B4-DCM and NTD-B7-DCM, prepared from traditional medicines used to treat schistosomiasis, displayed the highest activity (IC50 = 30.5 μg/mL and 30.8 μg/mL, respectively) against Schistosoma mansoni adult worms. NTD-B2-DCM, also obtained from an antischistosomal remedy, was the most active against female and male adult Onchocera ochengi worms (IC50 = 76.2 μg/mL and 76.7 μg/mL, respectively). Antitrypanosomal assay of the extracts against Trypanosoma brucei brucei gave the most promising results (IC50 = 5.63 μg/mL to 18.71 μg/mL). Incidentally, NTD-B4- DCM and NTD-B2-DCM, also exhibited the greatest antitrypanosomal activities (IC50 = PLOS NEGLECTED TROPICAL DISEASES PLOS Neglected Tropical Diseases | https://doi.org/10.1371/journal.pntd.0008919 December 31, 2020 1 / 21 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Twumasi EB, Akazue PI, Kyeremeh K, Gwira TM, Keiser J, Cho-Ngwa F, et al. (2020) Antischistosomal, antionchocercal and antitrypanosomal potentials of some Ghanaian traditional medicines and their constituents. PLoS Negl Trop Dis 14(12): e0008919. https://doi.org/ 10.1371/journal.pntd.0008919 Editor: Sabine Specht, University of Zurich, SWITZERLAND Received: April 20, 2020 Accepted: October 26, 2020 Published: December 31, 2020 Peer Review History: PLOS recognizes the benefits of transparency in the peer review process; therefore, we enable the publication of all of the content of peer review and author responses alongside final, published articles. The editorial history of this article is available here: https://doi.org/10.1371/journal.pntd.0008919 Copyright: © 2020 Twumasi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the manuscript and its Supporting Information files. 5.63 μg/mL and 7.12 μg/mL, respectively). Following the favourable outcome of the antitry- panosomal screening, this assay was selected for bioactivity-guided fractionation. NTD-B4- DCM, the most active extract, was fractionated and subsequent isolation of bioactive con- stituents led to an eupatoriochromene-rich oil (42.6%) which was 1.3-fold (IC50 <0.0977 μg/ mL) more active than the standard antitrypanosomal drug, diminazene aceturate (IC50 = 0.13 μg/mL). Conclusion/Significance These findings justify the use of traditional medicines and demonstrate their prospects towards NTDs drug discovery.
Biochemical and haematological changes following an acute toxicity study of a hydro-ethanolic whole plant extract of Synedrella nodiflora (L) Gaertn in male Sprague-Dawley rats.
(Journal of Medical and Biomedical Sciences, 3(1):31-37., 2014) Adjei, S.; Amoateng, P.; Osei-Safo, D.; Ahedor, B.; N’guessan, B.B.; Addo, P.; Asiedu-Gyekye, I.J.
Synedrella nodiflora (L) Gaertn (family Asteraceae), a common weed in Ghana, is traditionally used for the management of epilepsy, hiccup and threatened abortion. To further promote the ethno-pharmacological uses of the plant, an acute toxicity of a hydro-ethanolic whole plant extract was assessed in male Sprague-Dawley rats. The lethal dose (LD50) and effects of a single oral admin-istration of the extract (1600, 3200 and 6400 mg kg-1) on haematological and serum biochemical parameters were measured. The extract produced no mortality in the rats treated during a 48-hour examination and after a subsequent 12-day assessment. Thus the LD50 was indicated as being greater than 6400 mg kg-1. The extract also did not significantly affect any of the haematological and serum biochemical indices. This result suggests that acute oral administration of the hydro-ethanolic extract of Synedrella nodiflora is virtually non-toxic in male Sprague-Dawley rats under normal laboratory conditions.
Chemical and Biological Investigation of the Stem of Dichapetalum Crassifolium
(University of Ghana, 2015-06) Onyame, H. A.; Osei-Safo, D.; Chama, M. A.; University of Ghana, College of Basic and Applied Sciences, School of Physical and Mathematical Sciences, Department of Chemistry
In the present study, the stem of Dichapetalum crassifolium was investigated for its phytochemical constituents and their biological properties. The petroleum ether extract yielded friedelan-3-one, friedelan-3β-ol and a mixture of friedelan-3-one and friedelan-3β-ol. The ethyl acetate extract yielded pomolic acid, dichapetalin M and maslinic acid as well as the friedelins and a mixture of β-sitosterol and stigmasterol. No solid was isolated from the methanol extract. These compounds were identified and characterized using comparative thin-layer chromatography, comparative melting point, mixed melting point, IR, 1H and 13C NMR spectroscopy. In the light of recent investigations suggesting that the dichapetalins and some other triterpenoids have a broad spectrum of biological activities coupled with the urgent need of potential anti-schistosomal agents, the crude extracts as well as three isolates; friedelan-3-one, β-sitosterol/stigmasterol and dichapetalin M were screened for their potential egg hatch inhibition activity against Schistosoma mansoni and Schistosoma haematobium. The petroleum ether, ethyl acetate and methanol crude extracts gave IC50 values of 443.7 ± 0.04, 638.0 ± 0.08 and 893.7 ± 0.08 μg/ml respectively. Among the tested isolates, friedelan-3-one, β-sitosterol/stigmasterol and dichapetalin M gave IC50 values of 378.1 ± 0.23, 177.9 ± 0.10 and 191.0 ± 0.12 μg/ml respectively. The observed egg hatch inhibition activity of the most active isolates, the mixture of β-sitosterol/stigmasterol and dichapetalin M, were however found to be about 11 and 12-fold respectively less potent compared to that of the standard drug, praziquantel (IC50 = 15.47 ± 0.06 μg/ml), used in the study. This study constitutes the first report of the chemical and biological investigation of this member of the family Dichapetalaceae. Among the compounds isolated, maslinic acid is reported for the first time from the plant family.
A comparative study of the antimicrobial activity of the leaf essential oils of chemo-varieties of Clausena anisata (Willd.) Hook. F. Benth.
(Elsevier B.V., 2010-11) Osei-Safo, D.; Addae-Mensah, I.; Garneau, F-X; Koumaglo, H.K.
The emergence of multiple drug resistance to human pathogenic organisms has necessitated a search for new antimicrobial substances from various sources including plants. The present study was carried out as part of this search using the essential oils of the leaves of three chemo-varieties of Clausena anisata (Willd.) Hook. f. ex Benth. namely, estragole, trans-anethole and feniculin-containing chemo-varieties. The oils were screened against six bacteria (Escherichia coli, Staphylococcus aureus, Salmonella typhi, Shigella sp., Proteus sp. and Pseudomonas aeruginosa) and three fungi (Candida albicans, Aspergillus niger and Aspergillus parasiticus) isolated from clinical specimen using the disc sensitivity test. Microbes which showed significant sensitivity were further assayed with various concentrations of the active extracts in a dilution sensitivity test. The microorganisms were also assayed against seven broad spectrum antibiotics: penicillin G, amoxycillin, ampicillin, tetracycline, ceftizoxime, fosfomycin and urotractin. Results from the disc sensitivity test showed that the estragole-rich oil exhibited significant antimicrobial activity against E. coli (16.3±0.3mm) and Shigella sp. (17.2±0.4 mm). The trans-anethole-rich oil exhibited less significant activity (11.4±0.7mm and 12.1±0.3mm respectively) whereas the feniculin-rich oil, acting alone and in combination with the trans-anethole-rich oil did not show any significant activity against the all microbes tested. Only the neat oils and their 1:2 dilutions showed visible inhibition of microbial growth in the dilution sensitivity test. The estragole-rich oil gave minimum inhibitory concentrations of 3.7, 6.7 and 13.2 mg/ml against C. albicans, S. aureus and E. coli respectively with corresponding ED50 values of 1.3, 2.1 and 1.2 mg/ml. The trans-anethole-rich oil gave a minimum inhibitory concentration of 1.8 mg/ml against C. albicans with an ED50 of 0.2 mg/ml. The findings suggest a significant antimicrobial activity of these plant essential oils though of lower efficacy compared to ampicillin. The results further suggest that such plant essential oils could potentially be exploited in the development of novel antibiotics.
Dichapetalin M from Dichapetalum madagascariense
(Elsevier B.V., 2008-08-08) Osei-Safo, D.; Chama, M.A.; Addae-Mensah, I.; Waibel, R.; Asomaning, W.A.; Oppong, I.V.
The roots of Dichapetalum madagascariensis have yielded the new dichapetalin M, together with the previously reported dichapetalin A. This brings to nine, the total number of dichapetalins so far isolated from the roots of the plant, and to thirteen, the total number of dichapetalins isolated from the Dichapetalaceae. Dichapetalin M exhibited greater toxicity towards brine shrimp larvae than dichapetalin A, which has demonstrated cell inhibition against various cancer cell lines.
The Dichapetalins - Unique Cytotoxic Constituents of the Dichapetalaceae, Phytochemicals as Nutraceuticals - Global Approaches to Their Role in Nutrition and Health
(InTech Publishers, 2012) Osei-Safo, D.; Chama, M.A.; Addae-Mensah, I.; Waibel, R.
Differential constituents in roots, stems and leaves of Newbouldia laevis Thunb. screened by LC/ESI-Q-TOF-MS
(Elsevier, 2020) Osei-Safo, D.; Amewu, R.K.; Dermane, A.; et al.
Newbouldia laevis (P. Beauv.) Seem. or “Boundary Tree” is a medium sized angiosperm in the Bignoniaceae family. It is native to tropical Africa, especially used in West Africa to mark property boundaries in rural areas. Despite its intensive use in folk medicine, the plant chemical composition is under investigated. The study is aimed at identifying the chemical constituents of N. laevis crude plant extracts by high-performance liquid chromatography (HPLC) on line with an untargeted high-resolution mass spectrometry. The used HPLC method showed to be suitable for the determination of withasomnine, newbouldine, and lapachol derivatives together with other known bioactive compounds like phytosterols and triterpenoids. The importance of these chemical constituents is discussed with respect to the role of N. laevis in West African ethnomedicine. © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).
Dual effect of Taraxacum officinale leaves: Anticholinergic and inhibitory effect on inflammatory cells in ovalbumin-sensitized guinea-pigs
(2011-12) Awortwe, C.; Sackeyfio, A.C.; Osei-Safo, D.; Bugyei, K.A.; Asiedu-Gyekye, I.J.
Bronchospasm is an important characteristic of allergen-induced airway inflammation. Taraxacum officinale herb is believed to have several therapeutic effects including anti-inflammatory properties. The anticholinergic effect of the T. officinale leaves extract (TOLE) was determined in ovalbumin (OA)-sensitized guinea-pig trachea. The test drugs (TOLE or prednisolone) were administered orally 1 h prior to aerosolized 2% ovalbumin challenge. Isolated ovalbumin-sensitized guinea-pig tracheal was challenged with acetylcholine and OA in the absence and presence of TOLE. The blood samples were collected and neutrophils, lymphocytes and monocytes (eosinophils, basophils and macrophages) counts assayed. Prednisolone (2.5 mg/kg body weight (BW) orally) was used as reference standard. TOLE application showed significant antagonistic effect on contraction of trachea to both acetylcholine (35.10 ± 0.04) and OA (18.6 ± 1.5). Also, the extract reduced monocytes (0.62 ± 0.23), lymphocytes (3.4 ± 0.59) and neutrophils (3.65 ± 0.20) counts in OA-sensitized guinea-pigs. Thus, TOLE possesses anticholinergic and reduces neutrophil, eosinophil and basophil counts in ovalbumin-sensitized guinea-pigs.
Evaluation of the quality of artemisinin-based antimalarial medicines distributed in Ghana and Togo.
(Malaria Research and Treatment, Article ID 806416, 2014) Osei-Safo, D.; Agbonon, A.; Konadu, D.Y.; Harrison, J.J.E.K.; Edoh, M.; Gordon, A.; Gbeassor, M.; Addae-Mensah, I.
This study, conducted as part of our overall goal of regular pharmacovigilance of antimalarial medicines, reports on the quality of 132 artemisinin-based antimalarial medicines distributed in Ghana and Togo. Three methods were employed in the quality evaluation – Basic (colorimetric) Tests for establishing the identity of the requisite Active Pharmaceutical Ingredients (APIs), semi-quantitative TLC assay for the identification and estimation of API content and HPLC assay for a more accurate quantification of API content. From the basic tests, only one sample totally lacked API. The HPLC assay, however, showed that 83.7% of the ACTs and 57.9% of the artemisinin-based monotherapies failed to comply with International Pharmacopoeia requirements due to insufficient API content. In most of the ACTs, the artemisinin component was usually the insufficient API. Generally, there was a good correlation between the HPLC and SQ-TLC assays. The overall failure rates for both locally-manufactured (77.3%) and imported medicines (77.5%) were comparable. Similarly the unregistered medicines recorded a slightly higher overall failure rate (84.7%) than registered medicines (70.8%). Only two instances of possible cross-border exchange of medicines were observed and there was little difference between the medicine quality of collections from border towns and those from inland parts of both countries.
An extract of Synedrella nodiflora (L) Gaertn exhibits antidepressant properties through monoaminergic mechanisms
(Metabolic Brain Disease, 2018-08) Amoateng, P.; Kukuia, K.K.E.; Mensah, J.A.; Osei-Safo, D.; Adjei, S.; Eklemet, A.A.; Vinyo, E.A.; Karikari, T.K.
Synedrella nodiflora (SNE) has been used traditionally for many neurological conditions and some of these neuroactive effects have been scientifically substantiated. The usefulness of SNE in depression has however not been investigated despite the availability of data in other disease models indicating it may be useful. The present study therefore examined the effect of SNE in acute murine models of depression and the possible mechanisms mediating its activities in these models. Preliminary qualitative phytochemical and high performance liquid chromatography (HPLC) screening were conducted on SNE. The behavioural effects of SNE (100, 300 and 1000 mg/kg) pre-treated mice were examined in the forced swimming (FST) and tail suspension (TST) tests. Behavioural events such as mobility (swimming, climbing, curling and climbing), and immobility, were scored. The possible involvement of monoamines in the effects of SNE was assessed in the TST by pre-treating mice with α-methyldopa, reserpine and para-chlorophenylalanine (pCPA) in separate experiments. Flavonoids, tannins, saponins, alkaloids, cardiac glycosides, coumarins, triterpenes, sterols, anthraquinones and phenolic compounds were present in SNE. HPLC analysis revealed the presence of two major constituents observed at retention times 42.56 and 46.51 min, with percentage composition of 45.72% and 36.88% respectively. SNE significantly reduced immobility scores in both FST and TST, suggesting antidepressant effects. The antidepressant properties of SNE were reversed by the pre-treatment of α-methyldopa, reserpine and pCPA, suggesting a possible involvement of monoamines (noradrenaline and serotonin) in its mechanism(s) of actions. SNE exhibits antidepressant effects, possibly mediated through an interplay of enhancement of noradrenergic and serotoninergic mechanisms. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
Further Validation of a Rapid Screening Semiquantitative Thin-Layer Chromatographic Method for Marketed Antimalarial Medicines for Adoption in Malawi
(Journal of Analytical Methods in Chemistry, 2018-05) Osei-Safo, D.; Chikowe, I.; Harrison, J.J.E.K.; Yeboah, D.K.; Addae-Mensah, I.
A recently developed semiquantitative thin-layer chromatographic (SQ-TLC) assay has been employed in postmarketing surveillance of antimalarial medicines used in Malawi prior to HPLC assay. Both methods gave analogous results in a significant majority of the samples, with a good correlation ( r = 0.9012) for the active pharmaceutical ingredients of the dosage forms assayed. Artemether-containing medicines had the highest percentage (92.67%) of samples with comparable results for both assays. The lowest percentage (66.67%) was observed in artesunate-containing medicines. The SQ-TLC method was validated for specificity, accuracy, precision, linearity, and stability according to the International Conference on Harmonisation guidelines, with the results falling within acceptable limits. For specificity, retention factor values of the test samples and reference standards were comparable, while accuracy and precision of 91.1 ± 5.7% were obtained for all samples. The method was linear in the range 1.0–2.0 µ g/spot with a correlation coefficient of r = 0.9783. Stability tests also fell within acceptable limits. In this study, we present the validation of the SQ-TLC method and propose its adoption as a rapid screening tool for field estimation of the quality of antimalarial and other essential medicines in Malawi and other parts of the developing world prior to a more accurate HPLC assay.
Glycine/NMDA Receptor Pathway Mediates the Rapid-onset Antidepressant Effect of Alkaloids From Trichilia Monadelpha
(2021) Kukuia, K.K.E.; Mensah, J.A.; Amoateng, P.; Osei-Safo, D.; Koomson, A.E.; Torbi, J.; Adongo, D.W.; Ameyaw, E.O.; Ben, I.O.; Amponsah, S.K.; Bugyei, K.A.
Introduction: Major depressive disorder is often associated with suicidal tendencies, and this condition accentuates the need for rapid-acting antidepressants. We previously reported that Alkaloids (ALK) from Trichilia monadelpha possess antidepressant action in acute animal models of depression and that this effect is mediated through the monoamine and L-arginine NO-cGMP pathways. This study investigated the possible rapid-onset antidepressant effect of ALK from T. monadelpha and its connection with the glycine/NMDA receptor pathway. Methods: The onset of ALK action from T. monadelpha was evaluated using the Open Space Swim Test (OSST), a chronic model of depression. The modified forced swimming and tail suspension tests were used to assess the effect of the ALK on the glycine/NMDA receptor pathway. The Instutute of Cancer Research (ICR) mice were treated with either ALK (30–300 mg/kg, orally [PO]), imipramine (3–30 mg/kg, PO), fluoxetine (3–30 mg/kg, PO), or saline. To identify the role of glycine/NMDA receptor pathway in the effect of ALK, we pretreated mice with a partial agonist of the glycine/NMDA receptor, D-cycloserine (2.5 mg/ kg, intraperitoneally [IP]), and an agonist of glycine/NMDA receptor, D-serine (600 mg/kg, IP), before ALK administration. Results: ALK reversed immobility in mice after the second day of drug treatment in the OSST. In contrast, there was a delay in the effects induced by fluoxetine and imipramine. ALK also increased mean swimming and climbing scores in mice. ALK was more efficacious than imipramine and fluoxetine in reducing immobility and increasing distance traveled. It is noteworthy that ALK was less potent than fluoxetine and imipramine. D-cycloserine potentiated mobility observed in the ALK- and fluoxetine-treated mice. In contrast, D-serine decreased mobility in the ALK-treated mice. Conclusion: The study results suggest that ALK from T. monadelpha exhibits rapid antidepressant action in mice, and the glycine/NMDA receptor pathway possibly mediates the observed effect.
A hydro-ethanolic extract of Synedrella nodiflora (L.) Gaertn ameliorates hyperalgesia and allodynia in vincristine-induced neuropathic pain in rats
(Journal of Basic and Clinical Physiology and Pharmacology, 2015-01) Amoateng, P.; Adjei, S.; Osei-Safo, D.; Ameyaw, E.O.; Ahedor, B.; N'Guessan, B.B.; Nyarko, A.K.
Background: The hydro-ethanolic extract of Synedrella nodiflora (L.) Gaertn whole plant has demonstrated analgesic effects in acute pain models. The extract has also demonstrated anticonvulsant effects in murine models of experimental epilepsy. The present study illustrates an evaluation of the hydro-ethanolic extract of the plant for possible analgesic properties in hyperalgesia and allodynia associated with vincristine-induced neuropathy in rats. Methods: Neuropathic pain was induced in Sprague-Dawley rats by injecting 100 μg/kg of vincristine sulphate on alternative days for 6 days (days 0, 2, 4, 8, 10 and 12). Vincristine-induced cold allodynia, mechanical hyperalgesia and thermal hyperalgesia were measured pre-vincristine administration and on days 15, 17 and 19 post-vincristine administration. The rats were then treated with S. nodiflora extract (SNE) (100, 300 and 1000 mg/kg), pregabalin (10, 30 and 100 mg/kg) and distilled water as vehicle daily for 5 days and pain thresholds were measured on alternate days for 3 days. Results: SNE and pregabalin produced analgesic properties observed as increased paw withdrawal latencies to mechanical, tactile, cold water stimuli and thermal hyperalgesic tests during the 5 days of treatment. Conclusions: The findings suggest that hydro-ethanolic extract of S. nodiflora possesses anti-hyperalgesic and anti-allodynic effects in vincristine-induced neuropathic pain in rats. © 2015 by De Gruyter 2015.
In Vitro Activity of Extract and Fractions of Natural Cocoa Powder on Plasmodium falciparum
(2012) Amponsah, S.K.; Bugyei, K.A.; Osei-Safo, D.; Addai, F.K.; Asare, G.; Tsegah, E.A.; Baah, J.; Ofori, M.; Gyan, B.A.
Several flavonoids isolated from certain plants have demonstrated antiplasmodial activity, after their initial indigenous use in malaria treatment. Cocoa has been found to be a rich food source of flavonoids in comparison with many common foods and beverages. The aim of this work was to investigate the in vitro activity of natural cocoa powder on the growth of Plasmodium falciparum. Prepared crude methanol extract was partitioned successively with petroleum ether, ethyl acetate, chloroform, and butanol. Total flavonoid concentration in the crude methanol extract and fractions was measured by the AlCl3 colorimetric assay. Direct inhibitory activity of the natural cocoa powder was assessed by culturing extract and fractions with P. falciparum in vitro. Greater antiplasmodial activity was observed in nonpolar solvent fractions (chloroform, ethyl acetate, and petroleum ether) compared with polar solvents. The chloroform fraction was most active, with mean – SEM 50% and 90% inhibition concentrations of 48.3 – 0.9 and 417 – 7.8 lg/mL, respectively. The study showed a weak association between total flavonoid concentration and antiplasmodial activity. Early trophozoite (ring-stage) synchronized cultures treated with the chloroform fraction of natural cocoa powder showed a decline in growth. Further reduction in parasitemia was also observed for other erythrocytic stages. These results suggest that natural cocoa powder has measurable direct in vitro inhibitory effect on P. falciparum and support the anecdotal reports of its ability to prevent malaria as a result of regular intake as a beverage.
Leishmanicidal Potential of Hardwickiic Acid Isolated From Croton sylvaticus
(Frontiers in Pharmacology, 2020-05-25) Crentsil, J.A.; Yamthe, L.R.T.; Anibea, B.Z.; Broni, E.; Kwofie, S.K.; Tetteh, J.K.A.; Osei-Safo, D.
Leishmania is a parasitic protozoon responsible for the neglected tropical disease Leishmaniasis. Approximately, 350 million people are susceptible and close to 70,000 death cases globally are reported annually. The lack of effective leishmanicides, the emergence of drug resistance and toxicity concerns necessitate the pursuit for effective antileishmanial drugs. Natural compounds serve as reservoirs for discovering new drugs due to their chemical diversity. Hardwickiic acid (HA) isolated from the stembark of Croton sylvaticus was evaluated for its leishmanicidal potential against Leishmania donovani and L. major promastigotes. The susceptibility of the promastigotes to HA was determined using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide/phenazine methosulfate colorimetric assay with Amphotericin B serving as positive control. HA showed a significant antileishmanial activity on L. donovani promastigotes with an IC50 value of 31.57± 0.06 µM with respect to the control drug, amphotericin B with IC50 of 3.35 ± 0.14 µM). The cytotoxic activity was observed to be CC50 = 247.83 ± 6.32 µM against 29.99 ± 2.82 µM for curcumin, the control, resulting in a selectivity index of SI = 7.85. Molecular modeling, docking and dynamics simulations of selected drug targets corroborated the observed antileishmanial activity of HA. Novel insights into the mechanisms of binding were obtained for trypanothione reductase (TR), pteridine reductase 1 (PTR1), and glutamate cysteine ligase (GCL). The binding affinity of HA to the drug targets LmGCL, LmPTR1, LdTR, LmTR, LdGCL, and LdPTR1 were obtained as -8.0, -7.8, -7.6, -7.5, -7.4 and -7.1 kcal/mol, respectively. The role of Lys16, Ser111, and Arg17 as critical residues required for binding to LdPTR1 was reinforced. HA was predicted as a Caspase-3 stimulant and Caspase-8 stimulant, implying a possible role in apoptosis, which was shown experimentally that HA induced parasite death by loss of membrane integrity. HA was also predicted as antileishmanial molecule corroborating the experimental activity. Therefore, HA is a promising antileishmanial molecule worthy of further development as a biotherapeutic agent
Long-term continuous administration of a hydro-ethanolic extract of Synedrella nodiflora (L) Gaertn in male Sprague-Dawley rats: Biochemical, haematological and histo-pathological changes
(Ghana Medical Journal, 2016-09) Amoateng, P.; Adjei, S.; Osei-Safo, D.; Ahedor, B.; Mahmood, S.A.; N’guessan, B.B.; Asiedu-Gyekye, I.J.; Nyarko, A.K.
Background: Conflicting reports about the toxicity of Synedrella nodiflora (L) Gaertn (family Asteraceae), a plant traditionally used in Ghana for the management of epilepsy, abound in literature. The present study evaluates the effect of a 90-day continuous oral administration of a hydro-ethanolic whole plant extract of Synedrella nodiflora (SNE) in male Sprague-Dawley rats. Methods: The toxicological evaluation of the extract (100, 300 and 1000 mgkg-1) was focused on haematological, serum biochemical parameters and histopathological changes of some isolated organs. Results: The extract produced no mortality in the rats treated during the study period. Only SNE 100 mgkg-1 produced significant decrease in white blood cell and neutrophil counts and an increase in albumin, globulin, total bilirubin, total protein and potassium levels. The higher doses (SNE 300 and 1000 mgkg-1) had no significant effect on all the haematological and biochemical parameters measured. Histopathological assessment of the liver, kidney and heart revealed no abnormalities in rats treated with the extracts. Only the SNE 1000 mgkg-1 produced distortions of the branching arrangements of the myocardial fibres and a congested vessel which indicates a healed infarction. Conclusions: The findings suggest hydro-ethanolic extract of Synedrella nodiflora (L) Gaertn generally has a low toxicity profile following a 90-day continuous oral administration in male Sprague-Dawley rats under the present laboratory conditions. However patients with renal or cardiac problems should use the plant with caution.
Making North–South Collaborations Work: Facilitating Natural Product Drug Discovery in Africa
(Springer link, 2019) Osei-Safo, D.; Kyeremeh, K.; Amewu, R.; et al.
Many global North–South collaborations seek to address different aspects of the Sustainable Development Goals (SDGs) for Africa . The role of the North in these collaborations is crucial from a funding point of view. However, the realisation of the SDG objectives for Africa will depend largely on strategies that are guided by the successes and challenges of previous and existing collaborative efforts. Globally, Africa has the highest disease burden with the leading causes of morbidity and mortality being malaria, tuberculosis, HIV and AIDS and more recently, cardiovascular diseases , diabetes and cancer. Neglected tropical diseases are also causing long-term detrimental health effects, resulting in huge social and economic losses. Ironically, the continent is endowed with a huge biodiversity resource that has the potential to provide novel and potent drug candidates but remains largely unexplored partly due to financial and infrastructural challenges. Developing the scientific research capabilities of African institutions towards drug discovery through global networks is, therefore, an important component of improving health systems on the continent. This chapter examines experiences from three North–South collaborations—the Royal Society’s Leverhulme Trust Africa Award (LTAA), Newton Advanced Fellowships (NAF) and Cambridge-Africa Partnership for Research Excellence (CAPREx)—and proposes the adoption of structures that extend the current focus on skill transfer to include the building and maintenance of sustainable infrastructure. It is believed that these thoughts and suggestions could promote sustainable collaborative research to provide good health and well-being (SDG3), quality education (SDG4), relevant infrastructure (SDG9) and reduced inequalities (SDG10) in Africa .
Medicinal Plants Used in the Treatment of Mental and Neurological Disorders in Ghana
(Evidence-based Complementary and Alternative Medicine, 2018-12) Amoateng, P.; Quansah, E.; Karikari, T.K.; Asase, A.; Osei-Safo, D.; Kukuia, K.K.E.; Amponsah, I.K.; Nyarko, A.K.
Ethnopharmacological Relevance. Mental and neurological disorders are a serious public health challenge globally, particularly in developing countries where cultural factors and limited access to standard healthcare have led to a reliance on traditional medicines. However, ethnopharmacological characterization of traditional medicines used to treat these diseases is lacking. In this study, an ethnobotanical description of plant species used in treating mental and neurological disorders in Ghana and an update of their experimentally validated pharmacological relevance are provided. Materials and Methods. Two hundred herbalists agreed to participate but sixty-six specialized in treating mental and neurological disorders were interviewed on their traditional medical practice. Literature review was conducted to verify the experimentally validated pharmacological importance of the reported plants. Results. Thirty-two plant species belonging to twenty-eight families were identified. Most plant species had either analgesic (50%), anxiolytic (18.8%), or anticonvulsant (15.6%) properties. Others had reported sedative, anti-Alzheimer’s disease, motor coordination, antipsychotic, antidepressant, cognitive enhancement, and neuroprotective properties. While Ageratum conyzoides L. (Asteraceae) and Ocimum gratissimum L. (Lamiaceae) were the most commonly mentioned species with analgesic properties, Lantana camara L. (Verbenaceae) was the most-reported anxiolytic product, with Cymbopogon citratus DC. (Gramineae), Mangifera indica L., Tetrapleura tetraptera Schum Taub. (Fabaceae), and Persea Americana Mill (Lauraceae) being the most studied anticonvulsants. Conclusions. This study provides the first report specifically on medicinal plants used in treating mental and neurological disorders in Ghana. Most of the identified plants have been scientifically confirmed to possess neuro- and psychopharmacological properties and may serve as templates for drug development.
Mineral Fertilization Influences the Growth, Cryptolepine Yield, and Bioefficacy of Cryptolepis sanguinolenta (Lindl.) Schlt.
(MDPI, 2022) Amissah, J.N.; Alorvor, F.E.; Okorley, B.A.; Asare, C.M.; Osei-Safo, D.; Appiah-Opong, R.; Addae-Mensah, I.
Cryptolepis sanguinolenta (Lindl.) Schlt., the main source of cryptolepine alkaloid, is intensively exploited in the wild to treat malaria and Lyme disease. In this study, the influence of four inorganic fertilizers (supplying N, P, K, or NPK) and four growth periods (3, 6, 9, and 12 months after transplanting) on the herb’s root biomass, cryptolepine content and yield, and biological activities were investigated in a pot and field trial. The results showed the application of N (in the form of Urea or NPK) increased root biomass yield, cryptolepine content, and cryptolepine yield compared to unfertilized plants. The 9-month-old plants recorded the maximum cryptolepine content (2.26 mg/100 mg dry root) and cryptolepine yield (304.08 mg/plant), indicating the perfect time to harvest the herb. Plant age at harvest had a more significant influence (50.6–55.7%) on cryptolepine production than fertilizer application (29.2–33.3%). Cryptolepine extracts from 9- to 12-month-old plants had the highest antiplasmodial activity (IC50 = 2.56–4.65 g/mL) and drug selectivity index (2.15–3.91) against Plasmodium falciparum Dd2. These extracts were also cytotoxic to Jurkat leukaemia cell lines (CC50 < 62.56 g/mL), indicating the possible use of cryptolepine for cancer management. Growing the herb in the field increased cryptolepine yield 2.5 times compared to growth in a pot, but this did not influence the antiplasmodial activity of the extract. Commercial cultivation of C. sanguinolenta for 9 months combined with N application could be a promising solution to the sustainable use of this threatened medicinal species.