Ovicidal and Pediculicidal Activity of Indigofera suffruticosa Mill. Leaf Oil on Pediculus humanus capitis Egg to Adult Stages

Purpose

Pediculosis capitis, commonly known as head lice infestation, represents a significant health 26 problem for school children worldwide. Repeated and long-term usages of highly toxic pediculicides have resulted in the development of increased levels of resistance and do not kill louse eggs. Alternative pediculicides, such as herbal products, have recently been proposed for the treatment of head lice infestation, thereby decreasing toxicity.

Methods

This study analyzed the chemical composition of I. suffruticosa leaf extracts using GC–MS and evaluated the effects of Indigofera suffruticosa Mill. (I. suffruticosa) leaf extract on the mortality of head lice and their eggs.

Results

The major five components of the tested oils identified were as follows: n-hexadecanoic acid, hexadecanoic acid, ethyl ester, oleic acid, (E)-9-octadecenoic acid ethyl ester, and linoleic acid ethyl ester. The effective pediculicide of the I. suffruticosa leaf extracts affected head lice in all stages (egg, nymph, and adults). The concentrations of I. suffruticosa leaf extracts at 500 mg/mL produced the highest effective ovicidal on egg with 96.6% unhatching and pediculicide on nymphs and adults with 96.7 ± 5.7% and 86.7 ± 5.7% mortality, respectively, at 60 min (LT₅₀ value < 10 min). The analysis of the external structure of the adult-stage head lice by SEM examination revealed that dead lice exposed to I. suffruticosa leaf extract displayed damage to the outer smooth architecture and obstructed the respiratory spiracles.

Conclusion

We may conclude that the application of I. suffruticosa leaf extract produces an effective herbal pediculicide capable of affecting all stages of head lice.

Graphic Abstract