Browsing by Author "Oyweri Job"

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    Antimalarial Activity of Nigella sativa L. Seed Extracts and Selection of Resistance in Plasmodium berghei ANKA in a Mouse Model
    (Journal of Pathogens, 2021-02-03) Yusuf Rahma Udu; Oyweri Job; Gathirwa Jeremiah
    Chemotherapy plays a crucial role in malaria control. However, the main obstacle to treatment has been the rise of parasite resistance to most antimalarial drugs. Artemisinin- based combination therapies (ACTs) remain the most effective antimalarial medicines available today. However, malaria parasite tolerance to ACTs is now increasingly prevalent especially in Southeast Asia presenting the danger of the spread of ACTs resistance to other parts of the world. Consequently, this creates the need for alternative effective antimalarials. (erefore, this study sought out to determine antimalarial potential, safety, and resistance development of the extracts in a mouse model. Method. Methanolic and ethyl acetate extracts were obtained by solvent extraction. (e extracts were assayed for acute toxicity in vivo. Additionally, the two extracts were evaluated for antimalarial activity in vivo against Plasmodium berghei ANKA strain by the 4-day suppressive test at 500, 250, and 125 mg/kg/day. Packed cell volume was evaluated to determine anemia manifestation. Finally, continuous drug pressure experiment at 500 mg/kg and DNA amplification via PCR were conducted. (e amplicons underwent through Sanger sequencing. Results. (ere was no toxicity realized in the animals at 2000 mg/kg. Importantly, high parasitemia suppression of 75.52% and 75.30% using a dose of 500 mg/kg of methanolic and ethyl acetate extracts, respectively, was noted. (e extracts were able to reverse packed cell volume reduction. Nigella sativa-resistant phenotype was selected as delayed parasite clearance. However, there was no change in the nucleotide sequences of PbMDR1 and PbCRT genes. Conclusion. (e results provide room for future exploitation of the plant as an antimalarial
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    In Vitro and In Vivo Antimalarial Activity of Nigella Sativa L. Extracts
    (Journal of Medicinal Plants Research, 2019-12) Oyweri Job; Mohammed Awadh; Udu Rahma; Gathirwa Jeremiah; Too Edwin; Omondi Protus; Kimani Francis; Hashim Suhaila; Abubakar Laila
    The Arabs, Asians and, Traditional Health Practitioners in Mombasa county found in Kenya have been using Nigella sativa L. seeds to traditionally manage malaria associated symptoms that is, headache, fever, chills, loss of appetite among others. The present study investigated in vitro antiplasmodial, in vivo antimalarial activities and safety of different extracts of N. sativa. Five extracts obtained via aqueous extraction and sequential extraction using hexane, dichloromethane, ethyl acetate and methanol were tested against in vitro cultures of Plasmodium falciparum. The most active extracts (methanolic and ethyl acetate) were assessed for cytotoxicity and toxicity. The two active extracts were evaluated in vivo against Plasmodium berghei ANKA strain at 500, 250 and 125 mg/kg/day. On in vitro assay, methanolic and ethyl acetate extracts showed good activity with IC50 of 80.48±12.29 and 69.81±5.24 µg/ml against W2 strain and 31.93±4.31 and 53.79±6.02 µg/ml against D6 strain, respectively. The extracts exhibited weak cytotoxicity on Vero cells and high parasitemia suppression of 75.52 and 75.30% at 500 mg/kg dose of methanolic and ethyl acetate extracts respectively. Notably, there was significant decrease (p<0.001) in activity with lower doses of the extracts. The results explain thetraditional use of this plant in the Middle East and Mombasa County