TY  - JOUR
A1  - Muthaura, Charles N.
A1  - Keriko, Joseph M.
A1  - Mutai, Charles
A1  - Yenesew, Abiy
A1  - Heydenreich, Matthias
A1  - Atilaw, Yoseph
A1  - Gathirwa, Jeremiah W.
A1  - Irungu, Beatrice N.
A1  - Derese, Solomon
T1  - Antiplasmodial, cytotoxicity and phytochemical constituents of four maytenus species used in traditional medicine in Kenya
JF  - The natural products journal
N2  - Background: In Kenya, several species of the genus Maytenus are used in traditional medicine to treat many diseases including malaria. In this study, phytochemical constituents and extracts of Maytenus undata, M. putterlickioides, M. senegalensis and M. heterophylla were evaluated to determine compound/s responsible for antimalarial activity. 
Objective: To isolate antiplasmodial compounds from these plant species which could be used as marker compounds in the standardization of their extracts as a phytomedicine for malaria. 
Methods: Constituents were isolated through activity-guided fractionation of the MeOH/CHCl3 (1:1) extracts and in vitro inhibition of Plasmodium falciparum. Cytotoxicity was evaluated using Vero cells and the compounds were elucidated on the basis of NMR spectroscopy.
Results: Fractionation of the extracts resulted in the isolation of ten known compounds. Compound 1 showed promising antiplasmodial activity with IC50, 3.63 and 3.95 ng/ml against chloroquine sensitive (D6) and resistant (W2) P. falciparum, respectively and moderate cytotoxicity (CC50, 37.5 ng/ml) against Vero E6 cells. The other compounds showed weak antiplasmodial (IC50 > 1.93 mu g/ml) and cytotoxic (CC50 > 39.52 mu g/ml) activities against P. falciparum and Vero E6 cells, respectively. 
Conclusion: (20 alpha)-3-hydroxy-2-oxo-24-nor-friedela-1(10),3,5,7-tetraen-carboxylic acid-(29)-methyl-ester (pristimerin) (1) was the most active marker and lead compound that warrants further investigation as a template for the development of new antimalarial drugs. Pristimerin is reported for the first time in M. putterlickioides. 3-Hydroxyolean-12-en-28-oic acid (oleanolic acid) (5), stigmast-5-en-3-ol (beta-sitosterol) (6), 3-oxo-28-friedelanoic acid (7), olean-12-en-3-ol (beta-amyrin) (8), lup-20(29)-en-3-ol (lupeol) (9) and lup-20(29)-en-3-one (lupenone) (10) are reported for the first time in M. undata.
KW  - Antimalarial plants
KW  - antiplasmodial
KW  - cytotoxicity
KW  - marker compound
KW  - Maytenus spp.
KW  - phytomedicine
KW  - pristimerin
Y1  - 2017
U6  - https://doi.org/10.2174/2210315507666161206144050
SN  - 2210-3155
SN  - 2210-3163
VL  - 7
IS  - 2
SP  - 144
EP  - 152
PB  - Bentham Science Publ.
CY  - Sharjah
ER  - 
TY  - JOUR
A1  - Atilaw, Yoseph
A1  - Duffy, Sandra
A1  - Heydenreich, Matthias
A1  - Muiva-Mutisya, Lois
A1  - Avery, Vicky M.
A1  - Erdelyi, Mate
A1  - Yenesew, Abiy
T1  - Three Chalconoids and a Pterocarpene from the Roots of Tephrosia aequilata
JF  - Molecules
N2  - In our search for new antiplasmodial agents, the CH2Cl2/CH3OH (1:1) extract of the roots of Tephrosia aequilata was investigated, and observed to cause 100% mortality of the chloroquine-sensitive (3D7) strain of Plasmodium falciparum at a 10 mg/mL concentration. From this extract three new chalconoids, E-2,6-dimethoxy-3,4-(2,2-dimethyl)pyranoretrochalcone (1, aequichalcone A), Z-2,6-dimethoxy-3,4-(2,2-dimethyl)pyranoretrochalcone (2, aequichalcone B), 4-ethoxy-3-hydroxypraecansone B (3, aequichalcone C) and a new pterocarpene, 3,4:8,9-dimethylenedioxy-6a,11a-pterocarpene (4), along with seven known compounds were isolated. The purified compounds were characterized by NMR spectroscopic and mass spectrometric analyses. Compound 1 slowly converts into 2 in solution, and thus the latter may have been enriched, or formed, during the extraction and separation process. The isomeric compounds 1 and 2 were both observed in the crude extract. Some of the isolated constituents showed good to moderate antiplasmodial activity against the chloroquine-sensitive (3D7) strain of Plasmodium falciparum.
KW  - Tephrosia aequilata
KW  - chalcone
KW  - retrochalcone
KW  - aequichalcone A
KW  - aequichalcone B
KW  - aequichalcone C
KW  - pterocarpene
KW  - antiplasmodial
Y1  - 2017
U6  - https://doi.org/10.3390/molecules22020318
SN  - 1420-3049
VL  - 22
IS  - 2
PB  - MDPI
CY  - Basel
ER  -