Browsing by Author "Kino, H"

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    PublicationOpen Access
    Antimalarial activity of methanolic extracts from plants used in Kenyan ethnomedicine and their interactions with chloroquine (CQ) against a CQ-tolerant rodent parasite, in mice.
    (Mount Kenya University, 2007-04) Muregi, FW; Ishih, A; Miyase, T; Suzuki, T; Kino, H; Amano, T; Mkoji, GM; Terada, M
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    PublicationOpen Access
    Chromosomal mapping of host resistance loci to Trichinella spiralis nematode infection in rats.
    (Mount Kenya University, 2006-02) Suzuki, T; Ishih, A; Kino, H; Muregi, FW; Takabayashi, S; Nishikawa, T; Takagi, H; Terada, M
    The differences in host response among strains of rats to intestinal nematode parasite Trichinella spiralis infection could provide a powerful benefit for further elucidation of molecular interactions between the host and the parasite. Using several strains of rats, we previously observed that DA strain is a strong responder and F344 strain is a weak responder with respect to expulsion of the adult worm. To identify the host resistance loci, quantitative trait loci (QTLs) analysis in F2 population from crosses between DA and F344 strains was performed. One significant QTL (designated as Tspe) was mapped to the middle region of chromosome 9. In addition, the effect of DA allele at Tspe locus could act recessively and lead to the rejection of more adult worms from the gut. The results from the present study provide more insights on host-parasite interactions, which may be useful in facilitating the development of novel approaches for treatment and control of intestinal parasites in human and domestic livestock.
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    PublicationOpen Access
    In Vivo antimalarial activity of aqueous extracts from Kenyan medicinal plants and their chloroquine (CQ) potentiation effects against a blood-induced CQ-resistant rodent parasite in mice.
    (Mount Kenya University, 2007-04) Muregi, FW; Ishih, A; Suzuki, T; Kino, H; Amano, T; Mkoji, GM; Miyase, T; Terada, M
    Hot water extracts from eight medicinal plants representing five families, used for malaria treatment in Kenya were screened for their in vivo antimalarial activity in mice against a chloroquine (CQ) resistant Plasmodium berghei NK65, either alone or in combination with CQ. Extracts of three plants, Toddalia asiatica (root bark), Rhamnus prinoides (leaves and root bark) and Vernonia lasiopus (root bark) showed high chemosuppression in the range 51%-75%. Maytenus acuminata, M. heterophylla, M. senegalensis and Rhamnus staddo had moderate activities of 33%-49% parasitaemia suppression in the root bark and/or leaf extracts, while Withania somnifera (root bark) had a non-significant suppression (21%). In combination with CQ, extracts of V. lasiopus (all parts), leaf extracts of M. senegalensis, R. prinoides and T. asiatica as well as root barks of M. heterophylla, R. staddo and T. asiatica had improved parasitaemia suppression in the range 38%-66%, indicating synergistic interactions. Remarkable parasitaemia suppression by the extracts, either alone or in combination with CQ resulted into longer survival of mice relative to the controls, in some cases by more than 2 weeks. Plants, which showed significant antimalarial activity including V. lasiopus, T. asiatica and R. prinoides, should further be evaluated in the search for novel agents against drug-resistant malaria.
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    PublicationOpen Access
    Plasmodium berghei: lack of antimalarial activity of an analogue of folate precursor, 2,4-diamino-6-hydroxymethylpteridine in a mouse model.
    (Mount Kenya University, 2008-11) Muregi, FW; Kino, H; Ishih, A
    It was earlier hypothesized that the malarial parasite may convert precursors of folate analogues to synthesize de novo inhibitors toxic to itself, but not to the mammalian cell. It was suggested that one such analogue, 2,4-diamino-6-hydroxymethylpteridine (DAP) may be converted to aminopterin (AMP), a known dihydrofolate reductase inhibitor. In the present study, we evaluated the ability of DAP to inhibit proliferation of Plasmodium berghei NK65 in mice, with(out) folinic acid rescue. Cumulative dosages of DAP ranging from 0.1 to 20mg/kg bw. administered either orally or intraperitoneally showed no suppression of parasite growth, or gave mild activities that were not statistically significant (P>0.05). Our findings do not seem to support the hypothesis of selective de novo metabolism of DAP to AMP by the malarial parasite.