In vitro antiprotozoal activity of abietane diterpenoids isolated from Plectranthus barbatus Andr.
Chromatographic separation of the n-hexane extract of the aerial part of Plectranthus barbatus led to the isolation of five abietane-type diterpenes: dehydroabietane (1); 5,6-didehydro-7-hydroxy-taxodone (2); taxodione (3); 20-deoxocarnosol (4) and 6α,11,12,-trihydroxy-7β,20-epoxy-8,11,13-abietatriene (5). The structures were determined using spectroscopic methods including one- and two-dimensional NMR methods. Compounds (1)-(3) and (5) are isolated here for the first time from the genus Plectranthus. The isolated abietane-type diterpenes tested in vitro for their antiprotozoal activity against erythrocytic schizonts of Plasmodium falciparum, intracellular amastigotes of Leishmania infantum and Trypanosoma cruzi and free trypomastigotes of T. brucei. Cytotoxicity was determined against fibroblast cell line MRC-5. Compound (2) 5,6-didehydro-7-hydroxy-taxodone showed remarkable activity with acceptable selectivity against P. falciparum (IC50 9.2 µM, SI 10.4) and T. brucei (IC50 1.9 µM, SI 50.5). Compounds (3)-(5) exhibited non-specific antiprotozoal activity due to high cytotoxicity. Compound (1) dehydroabietane showed no antiprotozoal potential.
Department of Pharmacognosy, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia. rmothana@ksu.edu.sa.
Ramzi A
RA
Mothana
Department of Pharmacognosy, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia. msalsaid@ksu.edu.sa.
Mansour S
MS
Al-Said
Department of Pharmacognosy, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia. nalmusayeib@ksu.edu.sa.
Nawal M
NM
Al-Musayeib
Department of Pharmacognosy, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia. aelgamal00@yahoo.com.
Ali A
AA
El Gamal
Department of Pharmacognosy, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia. salmassarani@ksu.edu.sa.
Shaza M
SM
Al-Massarani
Department of Pharmacognosy, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia. ajalreha@ksu.edu.sa.
Adnan J
AJ
Al-Rehaily
Department of Pharmacognosy, College of Pharmacy, Salman Abdulaziz University, Alkharj 11942, Saudi Arabia. mpharm101@hotmail.com.
Majed
M
Abdulkader
Laboratory for Microbiology, Parasitology and Hygiene (LMPH), Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Antwerp University, Universiteitsplein 1, B-2610 Antwerp, Belgium. louis.maes@uantwerpen.be.
Louis
L
Maes
D045784:Abietanes / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D000981:Antiprotozoal Agents / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D006801:Humans; D018314:Leishmania infantum / Q000187:drug effects; D007898:Leishmaniasis, Visceral / Q000188:drug therapy; D016778:Malaria, Falciparum / Q000188:drug therapy; D010963:Plasmodium falciparum / Q000187:drug effects; D031346:Plectranthus / Q000737:chemistry*; D014345:Trypanosoma / Q000187:drug effects
D045784:Abietanes; D000981:Antiprotozoal Agents