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Mbah GE, Ayiseh RB, Monya E, Ndi EM, Njotu FN, Kulu TK, Sakanari J, Lustigman S, Cho-Ngwa F. Differential susceptibility of Onchocerca ochengi adult male worms to flubendazole in gerbils and hamsters. Parasitol Res 2024; 123:186. [PMID: 38634933 DOI: 10.1007/s00436-024-08207-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 04/09/2024] [Indexed: 04/19/2024]
Abstract
Onchocerciasis is a devastating skin and eye disease that afflicts about 21 million people, most of whom live in sub-Saharan Africa. Its control with the microfilaricidal drug ivermectin is limited, thus necessitating the development of preclinical animal models to aid in the discovery of a macrofilaricide. Previously, we found that Onchocerca ochengi (the closest relative of the human O. volvulus) worm masses survive better in hamsters than in gerbils. The aim of this study was to compare the survival of O. ochengi adult male worms and their susceptibility to flubendazole (FBZ, a macrofilaricide) in gerbils and hamsters. The animals were intraperitoneally implanted with O. ochengi male worms, treated with FBZ, and sacrificed 35 days post-implantation. Unlike gerbils which had some worms moving freely in the peritoneum and some in newly formed nodules (neo-nodules), all the worms in the hamsters were found in neo-nodules. FBZ significantly decreased worm burden, motility, and viability in gerbils whereas it had no significant effect in hamsters. These results highlight a major difference in how O. ochengi adult male worms are sustained and affected by FBZ in gerbils compared to hamsters. Understanding the difference between these two models is important in the development of effective macrofilaricides for onchocerciasis.
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Affiliation(s)
- Glory Enjong Mbah
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
- Department of Biology, Higher Teacher Training College (HTTC), The University of Bamenda, Bamenda, Cameroon
- National Higher Polytechnic Institute (NAHPI), The University of Bamenda, Bamenda, Cameroon
| | - Rene Bilingwe Ayiseh
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon.
- Department of Biochemistry and Molecular Biology, Faculty of Science, University of Buea, Buea, Cameroon.
| | - Elvis Monya
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Emmanuel Menang Ndi
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Fabrice Ngoh Njotu
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Tessy-Koko Kulu
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Judy Sakanari
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA
| | - Sara Lustigman
- New York Blood Center, Lindsley F. Kimball Research Institute, New York City, NY, USA
| | - Fidelis Cho-Ngwa
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon.
- National Higher Polytechnic Institute (NAHPI), The University of Bamenda, Bamenda, Cameroon.
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Ayiseh RB, Mbah GE, Manfo FPT, Kulu TK, Njotu FN, Monya E, Ndi EM, Tumanjong IM, Mainsah EN, Sakanari J, Lustigman S, Cho-Ngwa F. Survival of worm masses of Onchocerca ochengi in gerbils and hamsters: implications for the development of an in vivo macrofilaricide screening model. Parasitol Res 2023:10.1007/s00436-023-07859-7. [PMID: 37154921 DOI: 10.1007/s00436-023-07859-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 04/27/2023] [Indexed: 05/10/2023]
Abstract
Onchocerciasis, the second leading infectious cause of blindness, afflicts approximately 21 million people globally. Its control is limited to the use of the microfilaricidal drugs, ivermectin and moxidectin. Both drugs are unable to kill the adult worms which can survive for up to 15 years in patients, justifying the urgent need for potent and novel macrofilaricides that kill adult worms. The development of such drugs has been hindered by the lack of an appropriate small laboratory animal model to evaluate potential drug candidates in vivo. This study assessed the survival of O. ochengi female worms and their embryos over time in two laboratory rodents: gerbils and hamsters and tested using "proof-of-concept" studies, whether known macrofilaricidal drugs can kill these worms. Animals were surgically implanted with mechanical or collagenase-liberated O. ochengi worm masses, and necropsied at various time points to test for survival. Recovered worm masses were assessed for viability by biochemical analysis (MTT/formazan assay) or fecundity (embryogram). Flubendazole (FBZ) administered at 20 mg/kg body weight was used to validate both rodent models. By day 26 post-implantation of 15 worm masses, a median of 7.00 (4.00-10.00) was recovered from hamsters, and 2.50 (2.00-4.00) from gerbils. Worm masses recovered from gerbils were mostly disintegrated or fragmented, with significantly higher fragmentation observed with collagenase-liberated worm masses. FBZ had no significant effect on the number of worm masses recovered, but enhanced embryo degradation in gerbils and reduced worm mass viability in hamsters. This exploratory study has revealed the gerbil and hamster as permissible rodents to adult female worms of O. ochengi. The hamsters appeared to maintain the worms longer, compared to gerbils.
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Affiliation(s)
- Rene Bilingwe Ayiseh
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon.
| | - Glory Enjong Mbah
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
- Department of Biology, Higher Teacher Training College (HTTC), The University of Bamenda, Bambili, Cameroon
- National Higher Polytechnic Institute (NAHPI), The University of Bamenda, Bambili, Cameroon
| | - Faustin Pascal Tsague Manfo
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Tessy-Koko Kulu
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Fabrice Ngoh Njotu
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Elvis Monya
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Emmanuel Menang Ndi
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Irene Memeh Tumanjong
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Evans Ngandung Mainsah
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Judy Sakanari
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA
| | - Sara Lustigman
- New York Blood Center, Lindsey F. Kimball Research Institute, New York City, NY, USA
| | - Fidelis Cho-Ngwa
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon.
- National Higher Polytechnic Institute (NAHPI), The University of Bamenda, Bambili, Cameroon.
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Ayiseh RB, Mbah GE, Monya E, Ndi EM, Sakanari J, Lustigman S, Cho-Ngwa F. Development and validation of small animal models for onchocerciasis and loiasis microfilaricide discovery. PLoS Negl Trop Dis 2023; 17:e0011135. [PMID: 36827447 PMCID: PMC9994675 DOI: 10.1371/journal.pntd.0011135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 03/08/2023] [Accepted: 02/01/2023] [Indexed: 02/26/2023] Open
Abstract
BACKGROUND Onchocerciasis (river blindness) caused by the filarial worm Onchocerca volvulus is a neglected tropical disease that affects the skin and eyes of humans. Mass drug administration with ivermectin (IVM) to control the disease often suffers from severe adverse events in individuals co-injected with high loads of Loa loa microfilariae (mf). Thus loiasis animal models for counter-screening of compounds effective against onchocerciasis are needed, as are the corresponding onchocerciasis screening models. The repertoire of such models is highly limiting. Therefore, this study was aimed at developing and validating mf immunocompetent small animal models to increase tools for onchocerciasis drug discovery. METHODOLOGY/PRINCIPAL FINDINGS O. ochengi mf from cattle skin and L. loa mf from human blood were used to infect BALB/c mice and Mongolian gerbils, and IVM was used for model validation. O. ochengi mf were given subcutaneously to both rodents while L. loa mf were administered intravenously to mice and intraperitoneally to gerbils. IVM was given orally. In an 8-day model of O. ochengi mf in BALB/c mice, treatment with IVM depleted all mf in the mice, unlike the controls. Also, in a 2.5-day model of L. loa mf in BALB/c, IVM significantly reduced mf in treated mice compared to the untreated. Furthermore, the gerbils were very susceptible to O. ochengi mf and IVM eradicated all mf in the treated animals. In the peritoneal L. loa mf gerbil model, IVM reduced mf motility in treated animals compared to the controls. In a 30-day gerbil co-injection model, IVM treatment cleared all O. ochengi mf and reduced motility of L. loa mf. Both mf survived for up to 50 days in a gerbil co-injection model. CONCLUSIONS/SIGNIFICANCE We have developed two immunocompetent small animal models for onchocerciasis and loiasis that can be used for microfilaricide discovery and to counter-screen onchocerciasis macrofilarides.
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Affiliation(s)
- Rene Bilingwe Ayiseh
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Glory Enjong Mbah
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Elvis Monya
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Emmanuel Menang Ndi
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Judy Sakanari
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California, United States of America
| | - Sara Lustigman
- Lindsley F. Kimball Research Institute, New York Blood Center, New York City, New York, United States of America
| | - Fidelis Cho-Ngwa
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
- * E-mail:
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Babiaka SB, Simoben CV, Abuga KO, Mbah JA, Karpoormath R, Ongarora D, Mugo H, Monya E, Cho-Ngwa F, Sippl W, Loveridge EJ, Ntie-Kang F. Alkaloids with Anti-Onchocercal Activity from Voacanga africana Stapf (Apocynaceae): Identification and Molecular Modeling. Molecules 2020; 26:E70. [PMID: 33375687 PMCID: PMC7795662 DOI: 10.3390/molecules26010070] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 12/16/2020] [Accepted: 12/22/2020] [Indexed: 12/13/2022] Open
Abstract
A new iboga-vobasine-type isomeric bisindole alkaloid named voacamine A (1), along with eight known compounds-voacangine (2), voacristine (3), coronaridine (4), tabernanthine (5), iboxygaine (6), voacamine (7), voacorine (8) and conoduramine (9)-were isolated from the stem bark of Voacangaafricana. The structures of the compounds were determined by comprehensive spectroscopic analyses. Compounds 1, 2, 3, 4, 6, 7 and 8 were found to inhibit the motility of both the microfilariae (Mf) and adult male worms of Onchocerca ochengi, in a dose-dependent manner, but were only moderately active on the adult female worms upon biochemical assessment at 30 μM drug concentrations. The IC50 values of the isolates are 2.49-5.49 µM for microfilariae and 3.45-17.87 µM for adult males. Homology modeling was used to generate a 3D model of the O. ochengi thioredoxin reductase target and docking simulation, followed by molecular dynamics and binding free energy calculations attempted to offer an explanation of the anti-onchocercal structure-activity relationship (SAR) of the isolated compounds. These alkaloids are new potential leads for the development of antifilarial drugs. The results of this study validate the traditional use of V. africana in the treatment of human onchocerciasis.
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Affiliation(s)
- Smith B. Babiaka
- Department of Chemistry, Faculty of Science, University of Buea, P.O. Box 63, Buea CM-00237, Cameroon;
- AgroEco Health Platform, International Institute of Tropical Agriculture, Cotonou, Abomey-Calavi BEN-00229, Benin
| | - Conrad V. Simoben
- Institute for Pharmacy, Martin-Luther-Universität Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle, Germany; (C.V.S.); (W.S.)
| | - Kennedy O. Abuga
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Nairobi, Nairobi P.O. Box 19676–00202, Kenya; (K.O.A.); (D.O.); (H.M.)
| | - James A. Mbah
- Department of Chemistry, Faculty of Science, University of Buea, P.O. Box 63, Buea CM-00237, Cameroon;
| | - Rajshekhar Karpoormath
- Department of Pharmaceutical Chemistry, School of Chemistry, University of KwaZulu-Natal, Durban 4001, South Africa;
| | - Dennis Ongarora
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Nairobi, Nairobi P.O. Box 19676–00202, Kenya; (K.O.A.); (D.O.); (H.M.)
| | - Hannington Mugo
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Nairobi, Nairobi P.O. Box 19676–00202, Kenya; (K.O.A.); (D.O.); (H.M.)
| | - Elvis Monya
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, P.O. Box 63, Buea CM-00237, Cameroon; (E.M.); (F.C.-N.)
| | - Fidelis Cho-Ngwa
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, P.O. Box 63, Buea CM-00237, Cameroon; (E.M.); (F.C.-N.)
| | - Wolfgang Sippl
- Institute for Pharmacy, Martin-Luther-Universität Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle, Germany; (C.V.S.); (W.S.)
| | - Edric Joel Loveridge
- Department of Chemistry, Swansea University, Singleton Park, Swansea SA2 8PP, UK
| | - Fidele Ntie-Kang
- Department of Chemistry, Faculty of Science, University of Buea, P.O. Box 63, Buea CM-00237, Cameroon;
- Institute for Pharmacy, Martin-Luther-Universität Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle, Germany; (C.V.S.); (W.S.)
- Institute of Botany, Technical University of Dresden, 01217 Dresden, Germany
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Cho-Ngwa F, Mbah GE, Ayiseh RB, Ndi EM, Monya E, Tumanjong IM, Mainsah EN, Sakanari J, Lustigman S. Development and validation of an Onchocerca ochengi adult male worm gerbil model for macrofilaricidal drug screening. PLoS Negl Trop Dis 2019; 13:e0007556. [PMID: 31260456 PMCID: PMC6625737 DOI: 10.1371/journal.pntd.0007556] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 07/12/2019] [Accepted: 06/18/2019] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Onchocerciasis currently afflicts an estimated 15 million people and is the second leading infectious cause of blindness world-wide. The development of a macrofilaricide to cure the disease has been hindered by the lack of appropriate small laboratory animal models. This study therefore, was aimed at developing and validating the Mongolian gerbil, as an Onchocerca ochengi (the closest in phylogeny to O. volvulus) adult male worm model. METHODOLOGY/PRINCIPAL FINDINGS Mongolian gerbils (Meriones unguiculatus) were each implanted with 20 O. ochengi male worms (collected from infected cattle), in the peritoneum. Following drug or placebo treatments, the implanted worms were recovered from the animals and analyzed for burden, motility and viability. Worm recovery in control gerbils was on average 35%, with 89% of the worms being 100% motile. Treatment of the gerbils implanted with male worms with flubendazole (FBZ) resulted in a significant reduction (p = 0.0021) in worm burden (6.0% versus 27.8% in the control animals); all recovered worms from the treated group had 0% worm motility versus 91.1% motility in control animals. FBZ treatment had similar results even after four different experiments. Using this model, we tested a related drug, oxfendazole (OFZ), and found it to also significantly (p = 0.0097) affect worm motility (22.7% versus 95.0% in the control group). CONCLUSIONS/SIGNIFICANCE We have developed and validated a novel gerbil O. ochengi adult male worm model for testing new macrofilaricidal drugs in vivo. It was also used to determine the efficacy of oxfendazole in vivo.
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Affiliation(s)
- Fidelis Cho-Ngwa
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Glory Enjong Mbah
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Rene Bilingwe Ayiseh
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Emmanuel Menang Ndi
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Elvis Monya
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Irene Memeh Tumanjong
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Evans Ngandung Mainsah
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, Buea, Cameroon
| | - Judy Sakanari
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California, United States of America
| | - Sara Lustigman
- Lindsley F. Kimball Research Institute, New York City, New York, United States of America
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Ngemenya MN, Djeukem GGR, Nyongbela KD, Bate PNN, Babiaka SB, Monya E, Kanso RK. Microbial, phytochemical, toxicity analyses and antibacterial activity against multidrug resistant bacteria of some traditional remedies sold in Buea Southwest Cameroon. BMC Complement Altern Med 2019; 19:150. [PMID: 31242939 PMCID: PMC6595550 DOI: 10.1186/s12906-019-2563-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 06/13/2019] [Indexed: 11/17/2022]
Abstract
Background Traditional medicine remedies are commonly used for treatment of diverse ailments including bacterial infections. The activity against resistant bacteria and safety of some remedies sold as anti-infective treatments in market places in Buea, Southwest Cameroon were investigated as potential alternative treatment to counter increasing antibiotic resistance. Methods Ten remedies were purchased, their components documented and microbial load estimated. Methanol extracts of the remedies were tested for antibacterial activity by disc diffusion and microdilution. Cytotoxicity was evaluated on monkey kidney epithelial cells (LLC-MK2) while acute oral toxicity was done in BALB/c mice for the bactericidal extract. Extracts were further analysed using phytochemical tests. Results All the remedies had microbial loads above the acceptable limit of 105 CFU/g. The highest activity was produced by extracts of four remedies (TP 1, 2, 4, 6a, 6b) against all clinical isolates among which three were active against four control strains. Zones of inhibition ranged from 8 to 27 mm. Two of the four extracts produced zones ≥20 mm against multidrug resistant clinical isolates of Citrobacter freundii and Escherichia coli but were less active compared to Gentamycin positive control (P < 0.0001–0.0014). The most active extracts also recorded minimum inhibitory concentrations of 1 to 4 mg/mL. One of them (TP2) was bactericidal against a clinical isolate of methicillin–resistant Staphylococcus aureus with a minimum bactericidal concentration of 8 mg/mL. Extracts of six remedies did not show cytotoxicity and no mortality or adverse effect was recorded in the acute oral toxicity test. Phytochemical screening showed the most active extracts contained relatively high amounts of alkaloids and flavonoids. Conclusion Only four of the eight remedies tested showed activity against multidrug resistant bacteria suggesting some of these remedies may not be effective against bacterial infections. Production and handling methods should be improved and the product quality controlled to ensure biosecurity. The remedies which were both active and non-toxic should be further investigated including in vivo experiments to assess their efficacy.
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Ngwewondo A, Tsague Manfo FP, Samje M, Monya E, Cho-Ngwa F. Macro and microfilaricidal activities of extracts of Annona senegalensis and Milletia comosa against Onchocerca ochengi and Loa loa. Exp Parasitol 2019; 198:71-78. [DOI: 10.1016/j.exppara.2019.02.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 01/15/2019] [Accepted: 02/10/2019] [Indexed: 11/26/2022]
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Cho-Ngwa F, Monya E, Azantsa BK, Manfo FPT, Babiaka SB, Mbah JA, Samje M. Filaricidal activities on Onchocerca ochengi and Loa loa, toxicity and phytochemical screening of extracts of Tragia benthami and Piper umbellatum. BMC Complement Altern Med 2016; 16:326. [PMID: 27576736 PMCID: PMC5004253 DOI: 10.1186/s12906-016-1319-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 08/25/2016] [Indexed: 12/29/2022]
Abstract
BACKGROUND Onchocerciasis is the world's second leading infectious cause of blindness. Its control is currently hampered by the lack of a macrofilaricidal drug and by severe adverse events observed when the lone recommended microfilaricide, ivermectin is administered to individuals co-infected with Loa loa. Therefore, there is the need for a safe and effective macrofilaricidal drug that will be able to cure the infection and break transmission cycles, or at least, an alternative microfilaricide that does not kill L. loa microfilariae (mf). METHODS Fourteen extracts from two medicinal plants, Tragia benthami and Piper umbellatum were screened in vitro against Onchocerca ochengi parasite and L. loa mf. Activities of extracts on male worms and microfilariae were assessed by motility reduction, while MTT/Formazan assay was used to assess biochemically the death of female worms. Cytotoxicity and acute toxicity of active extracts were tested on monkey kidney cells and Balb/c mice, respectively. RESULTS At 500 μg/mL, all extracts showed 100 % activity on Onchocerca ochengi males and microfilariae, while 9 showed 100 % activity on female worms. The methylene chloride extract of Piper umbellatum leaves was the most active on adult male and female worms (IC50s: 16.63 μg/mL and 35.65 μg/mL, respectively). The three most active extracts on Onchocerca ochengi females were also highly active on Loa loa microfilariae, with IC50s of 35.12 - 13.9 μg/mL. Active extracts were generally more toxic to the worms than to cells and showed no acute toxicity to Balb/c mice. Phytochemical screening revealed the presence of saponins, steroids, tannins and flavanoids in the promising extracts. CONCLUSIONS These results unfold potential sources of novel anti-Onchocerca lead compounds and validate the traditional use of the plants in onchocerciasis treatment.
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Affiliation(s)
- Fidelis Cho-Ngwa
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon.
| | - Elvis Monya
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Boris K Azantsa
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Faustin Pascal T Manfo
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Smith B Babiaka
- Department of Chemistry, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon
| | - James A Mbah
- Department of Chemistry, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Moses Samje
- ANDI Centre of Excellence for Onchocerciasis Drug Research, Biotechnology Unit, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Bamenda, P.O. Box 39, Bambili, Cameroon
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