Antiparasitic and antimicrobial isoflavanquinones from Abrus schimperi.
The EtOH extract of Abrus schimperi (Fabaceae), collected in Kenya, demonstrated significant activity against Leishmania donovani promastigotes with IC50 value of 3.6 microg/mL. Bioassay-guided fractionation of CHCl3 fraction using Centrifugal Preparative TLC afforded two antiparasitic isoflavanquinones, namely amorphaquinone (1) and pendulone (2). They displayed IC50 values of 0.63 microg/mL and 0.43 microg/mL, respectively, against L. donovani promastigotes. Both the compounds were also evaluated against L. donovani axenic amastigotes and amastigotes in THPI macrophage cultures. In addition, compounds 1 and 2 showed antiplasmodial activity against Plasmodium falciparum D6 and W2 strains, while 2 displayed antibacterial activity against Staphylococcus aureus and methicillin-resistant S. aureus (each IC50 1.44 microg/mL). The 1H and 13C data of 1, not fully assigned previously, were unambiguously assigned using 1D and 2D NMR HMBC and HMQC experiments. In addition, the absolute stereochemistry of the isolated compounds 1 and 2 was revised as C-(3S) based on Circular Dichroism experiments. This appears to be the first report of amorphaquinone (1) and pendulone (2) from the genus Abrus.
National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy, University of Mississippi, Mississippi 38677, USA.
Aziz A
AA
Rahman
Volodymyr
V
Samoylenko
Surendra K
SK
Jain
Babu L
BL
Tekwani
Shabana I
SI
Khan
Melissa R
MR
Jacob
Jacob O
JO
Midiwo
John P
JP
Hester
Larry A
LA
Walker
Ilias
I
Muhammad
D029912:Abrus / Q000737:chemistry*; D000890:Anti-Infective Agents / Q000737:chemistry / Q000302:isolation & purification*; D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification*; D045744:Cell Line, Tumor; D002942:Circular Dichroism; D006801:Humans; D007529:Isoflavones / Q000737:chemistry / Q000302:isolation & purification*; D009682:Magnetic Resonance Spectroscopy; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000737:chemistry; D011809:Quinones / Q000737:chemistry / Q000302:isolation & purification*
D000890:Anti-Infective Agents; D000972:Antineoplastic Agents, Phytogenic; D007529:Isoflavones; D010936:Plant Extracts; D011809:Quinones; C569897:amorphaquinone; C569898:pendulone