Chemical Profiling, Larvicidal Activity and Antihemolytic Property of Allium sativum L. and Allium cepa L. Essential Oil

Essential oils are plant derived concentrates of the secondary metabolites responsible for the aromatic flavor attributing to its various medicinal properties. Fresh Allium sativum ( A. sativum ) and Allium cepa ( A. cepa ) were subjected to steam distillation for isolation of essential oil characterized by performing Gas Chromatography – Mass Spectroscopy (GC-MS). Chromatogram of the essential oil depicted the presence diallyl sulfide (5.35%), 2-(2’-carbamoylphenoxy)-butanoic acid (2.64%), 2-ethyl-5-methylthiophene (0.42%), diallyl disulphide (18.76%), 3-(2-thia-4-pentenyl)-1-thia-cyclohex-5-ene (1.09%) and dimethyl tetrasulphide (0.15%), 2,4-Thiazolidinedione (0.01%), 5-chloro-2-hydroxy-1,3-dinitrobenzene (5.93%), 6-Methoxy-1-methyl-3,4-dihydroisoquinoline (47.91%) in A. sativum and A.cepa respectively. Larvicidal activity against third instar larvae of Anopheles stephensi ( A. Stephensi ) was assessed by following the standard protocol of World Health Organization. The 50% lethality (LC 50 ) of A. stephensi larvae was observed at 265.96 ± 1.88 ppm and 357.14 ± 2.36 ppm of A. sativum and A. cepa essential oil correspondingly. The mortality rate of the larvae was both time and dose dependent. Besides, the in vitro antihemolytic activity of the essential oil was also assessed using Sheep erythrocytes. The erythrocyte lysis was inhibited by the essential oils of both A. sativum and A. cepa in a concentration dependent manner with an IC 50 of 427.35 ± 1.23 µl and 549.45 ± 1.38 µl respectively. On a comparative assessment between the essential oils of A. sativum and A. cepa , the former exhibited better larvicidal activity against the disease-causing vector, A. stephensi . Still, both could serve as potent insecticidal agents after further identification of the responsible chemical compound and its mode of action.