[1] Univ Yaounde 1, Fac Sci, Dept Organ Chem, Yaounde, Cameroon
[2] Univ Goettingen, Dept Organ & Biomol Chem, D-37077 Gottingen, Germany
[3] Univ Karachi, HEJ Res Inst Chem, Int Ctr Chem & Biol Sci, Karachi 75270, Pakistan
[4] Univ Quebec, Dept Chem, PharmaQAM, Montreal, PQ H3C 3P8, Canada
[5] Univ Quebec, PharmaQAM, Lab LASEVE, Chaire Rech Agents Anticancereux Origine Nat, Chicoutimi, PQ G7H 2B1, Canada