Pediculicidal activity of certain plant essential oils against head lice Pediculus humanus capitis

This paper reports the pediculicidal activity of certain monoterpenoids of plant essential oils compared to several anti-head lice formulations. It also reports the molecular features required for a chemical to kill head lice. Live adult Pediculus humanus capitus were collected from children living in the Qabary area, Alexandria, Egypt and used in in vitro bioassays. The data demonstrated that the commercial formulation, Quick (0.5% malathion) was the most potent formulation against head lice, while Para plus was the least potent. It was clear that the potency of the tested monoterpenoids was at least similar to Quick. The data also revealed that, monoterpenoid phenols and alcohols were more potent against head lice than monoterpenoid aldehydes, esters and acyclic monoterpenoids. One of the molecular features that is evidently important for monoterpenoid toxicity against head lice is the presence of electronegative group such as a hydroxyl group. In conclusion, this study reports an alternative chemical control that is safer, and more effective against head lice.