Full Length Research Paper

Comparative essential oils composition and insecticidal effect of different tissues of Piper capense L., Piper guineense Schum. et Thonn., Piper nigrum L. and Piper umbellatum L. grown in Cameroon

Tchoumbougnang François¹*, Jazet Dongmo Pierre Michel², Sameza Modeste Lambert¹, Fombotioh Ndifor¹, Wouatsa Nangue Arlette Vyry¹, Amvam Zollo Paul Henri³ and Menut Chantal³

¹Laboratory of Biochemistry, Faculty of Science, University of Douala, PO Box 24157 Douala, Cameroon.

²ENSAI-University of Ngaoundéré, PO Box 455 Ngaoundéré, Cameroun.

³Ecole Nationale Supérieure de Chimie de Montpellier, 34296 Montpellier Cedex 5, France.

*Corresponding author. E-mail: tchoumbougnang@yahoo.fr.

Accepted 9 September, 2008

This study compared the chemical composition of the essential oils obtained by hydrodistillation of different tissues of Piper capense, Piper guineense, Piper nigrum and Piper umbellatum grown in Cameroon. The GC and GC/MS analysis showed qualitative and quantitative differences between these oils. Oils from the fruits were rich in a-pinene (5.6 - 12.3%) and b-pinene (6.7 - 59.3%). The other major constituents were sabinene (14.7%) for P. capense, limonene (15.8%) and b-caryophyllene (20.8%) for P. guineense. The oil from the fruits of P. nigrum contained sabinene (11.2%), d-3-carene (18.5%), limonene (14.7%) and b-caryophyllene (12.8%) while that of P. umbellatum content linalool (14.4%) and (E)-nerolidol (10.0%) as major constituents. The essential oil obtained from the leaves of P. capense was largely composed of a-pinene (12.8%), β-pinene (50.1%) and b-caryophyllene (12.4%). The most abundant constituents identified in the oil from the leaves of P. guineense were limonene (10.3%) and germacrene B (25.1%) while that from P. nigrum was characterized by its high amount of a-selinene (16.5%) and β-selinene (14.6%). β-pinene (10.8%), β-caryophyllene (28.2%) and (E)-nerolidol (16.5%) were the quantitative important constituents of the essential oils from the leaves of P. umbellatum. The oils from the lianas of P. guineense was rich in (Z, E)-a-farnesene (28.7%), limonene (19.7%) and myristicine (10.9%), while those from P. nigrum contained d-3-carene (14.4%) and β-caryophyllene (36.0%). The oil from the stems of P. capense contained mostly a-pinene (14.3%) and β-pinene (61.4%). The distillation of those from P. umbellatum did not produce any essential oil. Oils from the three fruits showed variable contact toxicity against Sitophilus zeamais with P. guineense being more toxic (LD₅₀ = 10.0 ± 0.3 µl/g) than P. capense (LD₅₀ = 16.1 ± 0.6 µl/g) and P. nigrum (LD₅₀ = 26.4 ± 1.5 µl/g). Poudrox (5%) used as a standard insecticide exhibited 100% mortality.

Key words: Piper capense L., P.guineense Schum. Et Thonn., P. nigrum L., P. umbellatum L, essential oils, a-pinene, b-pinene, b-caryophyllene, insecticidal, Sitophilus zeamais Motsch.