IN-VITRO LARVICIDAL ACTIVITY OF PEGNUM HARMALA EXTRACTS AGAINST LARVAE OF MALARIA VECTOR ANOPHELES STEPHENSI

Abstract

Malaria is a mosquito-borne parasitic disease affecting over 300 million people globally each year, causing high child mortality. It is primarily spread by female Anopheles mosquitoes, especially An. culicifacies and An. stephensi in Pakistan.The disease is caused by five Plasmodium species, with P. falciparum and P. vivax being the most dangerous. Despite medical advances, malaria still leads to around one million deaths annually, particularly in regions like Pakistan. Peganum harmala, a medicinal plant rich in alkaloids like harmine and harmaline, shows antibacterial and anti-protozoal activity. In currunt study larvae of Anopheles stephensi were collected from water bodies in Kohat, KPK, Pakistan for experimental studies. Leaves of Peganum harmala were gathered from the same region and processed into methanolic extracts using a rotary evaporator. The leaves were shade-dried, ground, and soaked in methanol for 21 days to obtain crude plant extracts. Stock solutions were prepared from the extract and diluted for in-vitro bioassays. Different concentrations of the extract were tested against mosquito larvae to observe mortality rates over 30 minutes. Result show that Peganum harmala crude extract caused the highest larval mortality (15.33 ± 2.51) at a concentration of 8ml/10ml, with an LD₅₀ value of 44.58, observed over a 5-hour period. The results indicate that the selected plant extracts, particularly in methanol, possess repellent and larvicidal properties, suggesting the presence of potent bioactive compounds. Although mortality was low in the first hour, it increased over time, peaking in the 4th hour at the highest concentration (8ml/10ml or 80%).