Planta Med 2018; 84(01): 59-64
DOI: 10.1055/s-0043-114426
Natural Product Chemistry and Analytical Studies
Original Papers
Georg Thieme Verlag KG Stuttgart · New York

Three New Abietane-Type Diterpenoids from Plectranthus africanus and Their Antibacterial Activities

Raïssa T. Nzogong
Laboratory of Natural Products Chemistry, Department of Chemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
,
Blaise K. Nganou
Laboratory of Natural Products Chemistry, Department of Chemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
,
Alex T. Tedonkeu
Laboratory of Natural Products Chemistry, Department of Chemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
,
Maurice D. Awouafack
Laboratory of Natural Products Chemistry, Department of Chemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
Institute of Natural Medicine, University of Toyama, Toyama, Japan
,
Mathieu Tene
Laboratory of Natural Products Chemistry, Department of Chemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
,
Takuya Ito
Institute of Natural Medicine, University of Toyama, Toyama, Japan
,
Pierre Tane
Laboratory of Natural Products Chemistry, Department of Chemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
,
Hiroyuki Morita
Institute of Natural Medicine, University of Toyama, Toyama, Japan
› Author Affiliations
Further Information

Publication History

received 27 April 2017
revised 04 June 2017

accepted 18 June 2017

Publication Date:
29 June 2017 (eFirst)

Abstract

Three new abietane-type diterpenoids, plectranthroyleanones A – C (1 – 3), together with five known compounds (4 – 8) were isolated from the methanol extract of the whole plant of Plectranthus africanus using column chromatography techniques. The structures of the new compounds were elucidated using a combination of 1D and 2D NMR and HRESIMS analyses. Compound 1 exhibited weak activities with minimal inhibitory concentration values of 75 µg/mL against gram-positive bacteria, Bacillus subtilis and Staphylococcus aureus, and 150 µg/mL against two gram-negative bacteria, Pseudomonas aeruginosa and Klebsiella pneumoniae, respectively, while 2 and 3 had moderate antibacterial activity against K. pneumoniae with a minimal inhibitory concentration value of 37.5 µg/mL.

Supporting Information