Chemical Composition and Bioactivity of Four Plant Essential Oils from Nigeria against Macrotermes subhyalinus (Rambur)

The present study was carried out to determine the anti-termitic activity of four plants essential oils (Monondora myristica seed, Piper umbellatum seed, Pinus sylvestry leaves and Piper nigrum seed) from Nigeria against Macrotermes subhyalinus (Rambus). The essential oils were extracted by steam distillation and graded into different concentrations (0.5, 1, 1.5, 2, 2.5 mL/L). The chemical composition of the oil was analyzed by GC-MS. The result of the contact and repellence test showed that, the activities of the essential oils against Macrotermes subhyalinus increases with dose and time. The results revealed that during contact test, all essential oils showed toxicity against Macrotermes subhyalinus but the effectiveness of the essential oils differs, the essential oil of Monondora myristica had the lowest contact activity for all doses administered,100% mortality of M. subhyalinus was observed with a dose of 0.5 mL/L of the essential oil after 10 minutes of exposure, while with the same dose, 100% mortality was observed with P. nigrium and P. umbellatum after 20 minutes and 5 minutes respectively. All the essential oils proved to be repellent against Macrotermes subhyalinus with the essential oil of Monondora myristica having the least repellency. From the GC-MS analysis, the major components of the essential oils of Monondora myristica, Piper umbellatum, Pinus syvestry and Piper nigrum are trans-13-octtadecenoic acid (25.18%), aromadendrene (13.74%), α- terpineol (27.17%) and linalool (21.73%) respectively. Therefore, significant variation was observed in repellence, and contact activities between different doses and time of exposure (P<0.05). The result shows that the essential oils had termicite activity against M. subhyalinus and it was dose and time dependent.