Bio

Dr. Kefa Ogonyo Bosire

Kefa Bosire is a lecturer in the Department of Pharmacology and Pharmacognosy at the School of Pharmacy. He previously worked at the Ministry of Health National Quality Control Laboratories as an analyst before joining University of Nairobi in 2003. Since then, he has been teaching undergraduate and postgraduate classes.

DR. BOSIRE KEFA OGONYO CV

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Publications


2005

OGONYO, DRBOSIREKEFA.  2005.  Asiatic acid induces apoptosis in SK-MEL-2 human melanoma cells.Park BC, Bosire KO, Lee ES, Lee YS, Kim JA. Cancer Lett. 2005 Jan 31;218(1):81-90.. Cancer Lett. 2005 Jan 31;218(1):81-90.. : Folio Morphol Abstract
Asiatic acid (AA) is a pentacyclic triterpene found in Centella asiatica. In the present study, the mechanism of anticancer effect of AA on skin cancer was investigated. AA decreased viability and induced apoptosis in human melanoma SK-MEL-2 cells in a time- and dose-dependent manner. AA also markedly increased intracellular reactive oxygen species (ROS) level and enhanced the expression of Bax but not Bcl-2 protein in the cells. In addition, AA-induced activation of caspase-3 activity in a dose-dependent manner. Pretreatment with Trolox, an antioxidant, significantly blocked the induction of Bax and activation of caspase-3 in AA-treated cells. Furthermore, Ac-DEVD-CHO, a specific caspase-3 inhibitor, and Trolox prevented the AA-induced apoptosis. AA did not elevate p53 nuclear protein levels that are present in a mutant form in SK-MEL-2 cells. These results suggest that AA-induced apoptosis may be mediated through generation of ROS, alteration of Bax/Bcl-2 ratio and activation of caspase-3, but p53-independent. These results further suggest that AA may be a good candidate for the therapeutic intervention of human skin cancer.

2004

OGONYO, DRBOSIREKEFA.  2004.  Jae Sung Lee, Jong Suk Lee, Jae Don Yoon, Sung-Mok Beak, Kefa O. Bosire, Yong Soo Lee, Jung-Ae: Production of lignin Peroxidase by Phellinus igniarius and Cytotoxic effects of Ligin hydrolysates derived from wood biomass on cancer cells. J. Appl. Pharmaco. J. Appl. Pharmacol. 12, 3, (2004) 189-193. : Folio Morphol Abstract
Asiatic acid (AA) is a pentacyclic triterpene found in Centella asiatica. In the present study, the mechanism of anticancer effect of AA on skin cancer was investigated. AA decreased viability and induced apoptosis in human melanoma SK-MEL-2 cells in a time- and dose-dependent manner. AA also markedly increased intracellular reactive oxygen species (ROS) level and enhanced the expression of Bax but not Bcl-2 protein in the cells. In addition, AA-induced activation of caspase-3 activity in a dose-dependent manner. Pretreatment with Trolox, an antioxidant, significantly blocked the induction of Bax and activation of caspase-3 in AA-treated cells. Furthermore, Ac-DEVD-CHO, a specific caspase-3 inhibitor, and Trolox prevented the AA-induced apoptosis. AA did not elevate p53 nuclear protein levels that are present in a mutant form in SK-MEL-2 cells. These results suggest that AA-induced apoptosis may be mediated through generation of ROS, alteration of Bax/Bcl-2 ratio and activation of caspase-3, but p53-independent. These results further suggest that AA may be a good candidate for the therapeutic intervention of human skin cancer.

2003

Bosire, KO.  2003.  An investigation of a traditional herbal therapy used to treat malaria in Kisii. Abstract

The plant Rhamnus prinoides L. Herit (Rhamnaceae) IS used in
traditional medicine for the treatment of malaria among other diseases
by the Kisii community. By using column chromatographic methods,
geshoidin was isolated and tentatively identified. Other isolates were also
obtained but were not identified.
Allextracts were found to have in vitro antimalarial activity. The highest
activitywas in the hexane and dichloromethane extracts with ICso values
of 19.9 /lgjml and 30.3 /lgjml,respectively. None of the extracts showed
toxicityin the brine shrimp test.
This study provides scientific basis for the use of the plant part in the
treatment ofmalaria by the herbalist in Kisii

1998

OGONYO, DRBOSIREKEFA.  1998.  Abuga K.O., Bosire K.O., Kokwaro G.O.: Concomitant administration of Theophylline and Oxamniquine in rats: Effects on Theophylline clearance. E.A.J.P.Sc. 1 (1998) 1-27.. E.A.J.P.Sc. 1 (1998) 1-27.. : Folio Morphol Abstract
Asiatic acid (AA) is a pentacyclic triterpene found in Centella asiatica. In the present study, the mechanism of anticancer effect of AA on skin cancer was investigated. AA decreased viability and induced apoptosis in human melanoma SK-MEL-2 cells in a time- and dose-dependent manner. AA also markedly increased intracellular reactive oxygen species (ROS) level and enhanced the expression of Bax but not Bcl-2 protein in the cells. In addition, AA-induced activation of caspase-3 activity in a dose-dependent manner. Pretreatment with Trolox, an antioxidant, significantly blocked the induction of Bax and activation of caspase-3 in AA-treated cells. Furthermore, Ac-DEVD-CHO, a specific caspase-3 inhibitor, and Trolox prevented the AA-induced apoptosis. AA did not elevate p53 nuclear protein levels that are present in a mutant form in SK-MEL-2 cells. These results suggest that AA-induced apoptosis may be mediated through generation of ROS, alteration of Bax/Bcl-2 ratio and activation of caspase-3, but p53-independent. These results further suggest that AA may be a good candidate for the therapeutic intervention of human skin cancer.

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