Planta Med 2005; 71(12): 1145-1151
DOI: 10.1055/s-2005-873164
Original Paper
Natural Product Chemistry
© Georg Thieme Verlag KG Stuttgart · New York

Novel Antimicrobial Diterpenoids from Turraeanthus africanus

Simplice Joel N. Tatsimo1 , Pierre Tane2 , Pullela V. Srinivas3 , Beibam L. Sondengam1 , Jacob Melissa3 , Christopher O. Okunji4 , 5 , 6 , Brian M. Schuster6 , Maurice M. Iwu4 , 5 , 6 , Ikhlas A. Khan3
  • 1Department of Organic Chemistry, University of Yaounde, Yaounde, Cameroon
  • 2Department of Chemistry, University of Dschang, Dschang, Cameroon
  • 3National Center for Natural Products Research, The University of Mississippi, University, MS, USA
  • 4International Centre for Ethnomedicine and Drug Development, Nsukka, Nigeria
  • 5Bioresources Development & Conservation Programme, Silver Spring, MD, USA
  • 6Division of Experimental Therapeutics, Walter Reed Army Institute of Research, Washington, DC, USA
Further Information

Publication History

Received: December 2, 2004

Accepted: June 20, 2005

Publication Date:
10 November 2005 (online)


The dichloromethane-methanol (1/1) extract of the stem bark of Turraeanthus africanus (Meliaceae) showed remarkable antimicrobial activity against Cryptococcus neoformans, Staphylococcus aureus and methicillin-resistant S. aureus. Phytochemical investigation of this extract afforded six new diterpenoid derivatives, (+)-16-acetoxy-12,15-epoxylabda-8(17),12,14-triene (3), [16(E),12S,15R]-16-acetoxy-12,15-epoxy-15-isopropoxy-ent-labda-8(17),13(16)-diene (turraeanin A, 4), [16(E),12R,15S]-16-acetoxy-12,15-epoxy-15-isopropoxy-ent-labda-8(17),13(16)-diene (turraeanin B, 5), [16(E),12S,15R]-16-acetoxy-12,15-epoxy-15-methoxy-ent-labda-8(17),13(16)-diene (turraeanin C, 6), [16(E),12R,15S]-16-acetoxy-12,15-epoxy-15-methoxy-ent-labda-8(17),13(16)-diene (turraeanin D, 7) and (12S,13S,15R)-12,15-epoxy-15-methoxy-ent-labd-8(17)-en-16-al (turraeanin E, 9) together with the known compounds, 15,16-epoxy-ent-labda-8(17),13(16),14-triene (1), (+)-pumiloxide (2), ent-labda-8(17),12 (E)-diene-15,16-dial (8) and 16-acetoxy-12(R),15-epoxy-15β-hydroxylabda-8(17),13 (16)-diene (10). Compound 10 was obtained as its acetoxy derivative (10a) and compound 11 was the product of hydrolysis of 6. Antimicrobial activity of the isolates was assayed and compounds 8, 9, 10a and 11 exhibited significant activities.


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