[1] Univ Vienna, Inst Pharmacognosy, Vienna, Austria
[2] Univ San Carlos, Fac Chem Sci & Pharm, Sch Biol Chem, Guatemala City, Guatemala
[3] Univ San Carlos, Fac Chem Sci & Pharm, Inst Chem & Biol Invest, Guatemala City, Guatemala
[4] Univ Salerno, Fac Pharm, Dept Phytochem, I-84100 Salerno, Italy
[5] Univ Dusseldorf, Dept Pharmaceut Biol, D-4000 Dusseldorf, Germany