Antiparasitic activity against headlice and headlouse nits of Annona squamosa seed preparation

Seeds of Annona squamosa L., Annonaceae have long been used as anti-headlice agents in humans. An active component against headlice is known to be a triglyceride with one oleate ester [1]. A petroleum ether extract of the seeds prepared as 20% w/w oil in water cream preparation is effective and biological stable formulation against headlice [2, 3]. However, the efficacy of Annona squamosa seed cream on headlouse nits has not been reported. The present study is focused on testing for the efficacy of freshly prepared 20% w/w Annona squamosa seed cream against human headlice and their nits in school girls. After 3 hours of hair exposure to 20g of the 20% Annona cream containing 9.4% w/w of the active component, triglyceride with one oleate ester, 92.4±12.3% of headlice in school girls were killed. For evaluation of the killing effect of Annona cream on headlouse nits, 20g of the cream was applied onto hair of each of 27 school girls for 3 hours, then shampooed off. After a week, subjects were investigated for amount of headlice and alive nits and found that 66.7% of the subjects still had young headlice (<26%) and medium amount of alive nits. After second treatment of the cream, 40.7% of the subjects contained <17% of young headlice and small amount of alive nits, while the third treatment provided 3.7% of the subjects who still have <7% of young headlice and none of alive nits. The results demonstrate that single treatment of 20% w/w freshly prepared Annona squamosa seed cream could kill 92% of headlice in school girls but could not kill their nits. The girls should be treated with the cream once a week for 3 weeks to kill young headlice developing from alive nits.

Acknowledgements: The author would like to thank The Royal Golden Jubilee PhD Program of The Thailand Research Fund for a contribution to the travel grant to present this work.

References: [1] Gritsanapan, W. et al. (2006) Planta Med. 72: 966. [2] Gritsanapan, W. et al. (1998) Abstract Book of 50^th IPC and 17^th FAPA Congress, Mumbai, India, p 1. [3] Tiengda, CH. et al. (2000) Southeast Asian J Trop Med Public Health 31 (Suppl 1): 174–7.