Repellent activity of Vitex negundo and Curcuma longa herbal extract against Simulium species in India.

Abstract

At present, use of synthetic pesticides to manage insects and other arthropods creates a number of issues that are related to the environment and public health. The goal of the present study is to find repellent activity of Vitex negundo and Curcuma longa herbal extracts against the wild species Simulium (blackfly) bite. We have studied Simulium biting behavior and tested the repellency of herbal extract obtained from Vitex negundo L. (Lamiales: Lamiaceae) and Curcuma longa L. (Zingiberal: Zingiberaceae) along with their essential oils in three locations in Arunachal Pradesh, India on human volunteers' resistance to Simulium (blackflies). The reported herbal extracts were incorporated to topical drug delivery vehicle as a cream and gel. The methanolic extract of Vitex negundo cream and gel formulation showed >2 h safety at 5% concentration and >5 h safety at 10% concentration in all the testing sites followed by ethyl acetate extract. Whereas, chloroform extract of Curcuma longa cream and gel formulation provided >1 h safety at 5% concentration and >4 h safety at 10% concentration. At an optimum concentration of 10%, the methanolic extract of Vitex negundo cream provided complete protection times (CPTs) 320.4, 358.6, and 346.4 min, respectively. These findings offer confirmation of the methanolic extract and chloroform extract potential for use in new blackfly repellents.