title: Bioactive steroidal alkaloids from Buxus macowanii Oliv.
abstract: Chemical investigation of the crude methanolic extract of Buxus macowanii resulted in the isolation of five new steroidal alkaloids, 31-hydroxybuxatrienone (1), macowanioxazine (2), 16α-hydroxymacowanitriene (3), macowanitriene (4), macowamine (5), along with five known steroidal bases, Nb-demethylpapillotrienine (6), moenjodaramine (7), irehine (8), buxbodine B (9) and buxmicrophylline C (10). Structures of compounds 1-10 were elucidated with the aid of spectroscopic methods including 1D and 2D NMR techniques and mass spectrometry. Compounds 1, 3, and 4 belong to a rare class of Buxus alkaloids having Δ(1,2) 9(10→19) abeo triene system. All isolates were evaluated for in vitro acetylcholinesterase (AChE) inhibitory activity and found to exhibit moderate to weak anti-AChE activity with IC50 values in the range of 10.8-98μM. Compounds 1 and 6 were also moderately active in BACE1 inhibitory assay.
authors.affiliation: Department of Chemistry, Richardson College for the Environmental and Science Complex, The University of Winnipeg, 599 Portage Avenue, Winnipeg, MB R3B 2G3, Canada; Department of Chemistry, The University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
authors.forename: Cheuk W
authors.initials: CW
authors.lastname: Lam
authors.affiliation: Department of Chemistry, Richardson College for the Environmental and Science Complex, The University of Winnipeg, 599 Portage Avenue, Winnipeg, MB R3B 2G3, Canada.
authors.forename: Andrew
authors.initials: A
authors.lastname: Wakeman
authors.affiliation: Department of Chemistry, Richardson College for the Environmental and Science Complex, The University of Winnipeg, 599 Portage Avenue, Winnipeg, MB R3B 2G3, Canada.
authors.forename: Abin
authors.initials: A
authors.lastname: James
authors.affiliation: Department of Chemistry, Richardson College for the Environmental and Science Complex, The University of Winnipeg, 599 Portage Avenue, Winnipeg, MB R3B 2G3, Canada. Electronic address: a.ata@uwinnipeg.ca.
authors.forename: Athar
authors.initials: A
authors.lastname: Ata
authors.affiliation: Department of Chemistry, Durban University of Technology, Durban, South Africa.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Gengan
authors.affiliation: National Center for Natural Products Research, Department of Pharmacognosy, School of Pharmacy, University of Mississippi, MS 38677, USA.
authors.forename: Samir A
authors.initials: SA
authors.lastname: Ross
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism; D000470:Alkaloids / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D053829:Amyloid Precursor Protein Secretases / Q000037:antagonists & inhibitors; D031235:Buxus / Q000737:chemistry*; D002800:Cholinesterase Inhibitors / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D020128:Inhibitory Concentration 50; D013256:Steroids / Q000737:chemistry*
chemical_list: D000470:Alkaloids; D002800:Cholinesterase Inhibitors; D013256:Steroids; D000110:Acetylcholinesterase; D053829:Amyloid Precursor Protein Secretases
keywords: 16α-Hydroxymacowanitriene; 31-Hydroxybuxatrienone; Acetylcholinesterase inhibitory activity; Buxus macowanii; Macowamine; Macowanioxazine