Fitoterapia 78 (2007) 470–473www.elsevier.com/locate/fitote

In-vitro pediculicidal activity of Hedychium spicatum essential oil

Varsha Jadhav ⁎, Anagha Kore, V.J. Kadam

Bharati Vidyapeeth's College of Pharmacy, Navi Mumbai, Maharashtra, India

Received 17 November 2006; accepted 14 February 2007Available online 24 May 2007

Abstract

The essential oil extracted from rhizomes of Hedychium spicatum was evaluated for in-vitro pediculicidal activity. At 5%, 2%and 1% concentration the essential oil showed more significant activity than 1% permethrin based product.© 2007 Published by Elsevier B.V.

Keywords: Hedychium spicatum; Essential oil; Pediculicidal activity

1. Introduction

The three major lice that infest humans are Pediculus humanus capitis (head louse), Pthirus pubis (crab louse), andPediculus humanus humanus (body louse), the most common of which is the head louse. Infestations of human lice arerampant worldwide, chiefly among schoolchildren in both developed and developing countries and are more commonbetween the ages of 5 and 11 years. Infestation rates are usually higher among girls than boys [1–4]. The head lice arenot a major health hazard or disease vector, but can cause considerable distress due to scalp erythema, itching andpotential secondary infections. Pruritis is the most common symptom of head lice infestation. Bite reactions,excoriations, cervical lymphadenopathy, and conjunctivitis are also common manifestations [2,5].

The adult louse is 2 to 3 mm long and usually pale gray, although color may differ. The female lives up to 3 to4 weeks. After mating, an adult female louse lays one to six eggs a day for up to one month until death. The eggsincubated by body heat, hatch in 10 to 14 days. Once the eggs hatch, nymphs leave the shell casing, breed for about 9 to12 days, and develop into an adult lice and mate, and then females lay eggs. If not treated, this cycle may repeat itselfevery 3 weeks. While living on the head, the louse feeds by injecting small amounts of saliva and taking tiny amountsof blood from the scalp every few hours [3,6].

The spread of head lice is thought to occur mainly through direct head to head (hair to hair) contact. Transmissioncan also occur through personal belongings of an infested individual (combs, brushes, hats) [6,7].

The basic treatments for head lice are manual removal, topical insecticides. Manual removal includes use of nitcombs and wet combing. Topical insecticides used are pyrethrins, permethrin, lindane. Oral agents such astrimethoprim-sulfamethoxazole and ivermectin have shown anti-louse activity [3].

⁎ Corresponding author. Tel.: +91 22 27571122.E-mail address: drvmjadhav_bvcop@rediffmail.com (V. Jadhav).

0367-326X/$ - see front matter © 2007 Published by Elsevier B.V.doi:10.1016/j.fitote.2007.02.016

Fig. 1. Comparison of essential oil concentrations.

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The repeated application of insecticides has resulted in the development of resistance to these products. This hasimpelled a revival of interest in plant-derived insecticides. Also, plant essential oils have been widely reported asinsecticides [8–10].

The rhizomes of Hedychium spicatum are considered to have insect repelling property. The use of the essential oilhas been suggested in soap, hair oil, face powder and incense. This prompted us to evaluate the essential oil ofH. spicatum rhizomes for pedicilicidal activity [11,12].

2. Experimental

2.1. Plant

The dried sliced rhizomes of H. spicatum (Zingiberaceae) were purchased from the local market. The authenticationof the herb was done in Zandu Pharmaceuticals.

2.2. Extraction

Extraction of essential oil was carried out by hydrodistillation using a Clavenger apparatus [13].

2.3. Animals

P. humanus capitis (Phthiraptera: Pediculidae) were collected from school children in Mumbai, India on twooccasions. The insects were collected by combing the children scalps. After collection the lice were pooled and held onhuman hair strands in Petri dishes. The in-vitro tests were started within 1 h after collection.

Fig. 2. 5% Essential oil.

Fig. 3. 2% Essential oil.

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2.4. Pediculicidal activity of H. spicatum essential oil

1, 2 and 5% solutions of essential oil of H. spicatum were tested for the pediculicidal activity. The dilutions wereprepared in coconut oil as base. As a positive control, a 1% permethrin based over the counter preparation was used.For the tests, the lice clasping hair strands were immersed completely in the test solutions and the marketed preparationfor 1 min. The lice were then placed on previously moistened Whatman filter paper in Petri dishes to prevent the licefrom desiccation. Negative control lice were placed directly on the filter paper without any treatment. To simulatetreatment on an infested host, head lice were washed in tap water after 20 min and placed into a new Petri dish [14,15].The number of lice was 10 each in the 1, 2 and 5% essential oil group, 12 in the permethrin group, and 11 in controlgroup. Lice on the filter paper were examined under dissecting microscope. Examinations were performed after 5, 10,15, 20, 30, 45, 60, 90, and 120 min. The criteria used for survival of lice were extremely strict. If any minor signs of life,such as movements of antennae or minimal leg movements were observed (with or without stimulation by a forceps),the lice were categorized as alive. The lice were judged as dead if there were no vital signs at all.

The test was done in duplicate and average considered. Percentage mortality was calculated and graphs ofpercentage mortality versus time were plotted.

3. Result and discussion

Percentage mortality at each time point was calculated for all the groups.All lice treated with 5% H. spicatum essential oil did not show any vital signs after 5 min. All the lice treated with

2% and 1% H. spicatum essential oil did not show any vital signs at 20 min. After 30 min minimal movements wereobserved giving mortality of 85%, 80% and 75% for the 5%, 2% and 1% H. spicatum essential oil respectively. After2 h 100% mortality was observed in 5% and 2% H. spicatum essential oil treated groups. The 1% H. spicatum essential

Fig. 4. 1% Essential oil.

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oil treated group showed 95% mortality at the end of 2 h. All 14 head lice in the negative control group survived duringthe 2 h observation period. In the permethrin group, the mortality increased steadily from 54% at 5 min to 79% at 2 h.

The graphs of mortality versus time (min) were plotted to compare the three different concentrations of H. spicatumessential oil (Fig. 1) and each concentration was compared with permethrin group and negative control group (5%essential oil: Fig. 2; 2% essential oil: Fig. 3; 1% essential oil: Fig. 4 ).

Therefore the essential oil of H. spicatum shows more significant pediculicidal activity than the marketedpreparation containing 1% permethrin.

4. Conclusion

An effective pediculicide is required for the treatment of head lice infection considering the increase in resistance toinsecticides due to their repeated application. The essential oil from rhizomes of H. spicatum has shown moresignificant activity than the OTC product containing 1% permethrin. From this it can be concluded that the essential oilmay be a good substitute for the synthetic compounds if there is a further increase in resistance to these.

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