Antinociceptive effect, acute toxicity and chemical analysis of cold mechanically extracted N. Sativa seed oil

Pharmaceutical Science-Pharmacology for drug discovery

Abstract

Nigella  sativa  L. (Ranunculaceae),  seed  oil is traditionally  used  for pain,  stiffness  in the joints  and  eczema.  The  N. sativa  seed  oil (NSSO)  contains  an abundance  of monoterpenes  and essential  fatty acids of various  pharmacological actions.  The objective  of this study is to investigate  the antinociceptive  effect of single oral dose of NSSO on acetic acid-induced  writhing and hot plate induced algesia in mice. Further, the study also, aims to characterize  the chemical constituents  of NSSO by using GC/MS. Swiss albino mice were divided into two sets of three groups  consisting  of six animals  per group  for the assessment  of analgesic  effect  by hot plate  and by acetic  acid induced  writhing  methods. Group  I, received  distilled  water (10 ml/kg,  p.o.); group II, received  diclofenac  sodium  (2.5 mg/100g,  p.o.); and group III, received  NSSO (0.5 ml/100g,  p.o.).  After  NSSO  administration  the animals  were  placed  on the  hot  plate  and  their  response  was  noted  down  at different  time interval.  Further,  another  set of animals  of other  three  groups  were subjected  to acetic  acid induced  writhing  test after 30 minutes  of drug administration.  The results of the study showed that NSSO significantly  (p<0.05) increased  the latency to thermal stimulus,  and also, there was significant (p<0.01) reduction in the number of writhes induced by 0.07% acetic acid. The GC/MS chromatogram of NSSO showed a total of 50 compounds.  The  LD50   of NSSO  was  greater  than  5 g/kg.  Thus  in conclusion,  NSSO  (0.5ml/100g,  p.o.)  showed  a significant  analgesic  effect against acetic acid induced writhing and also in hot plate model in mice. The phytochemical  analysis  of NSSO showed the presence  of several active principles, primarily linoleic acid and thymoquinone.  The presence of linoleic acid and thymoquinone  in NSSO, possibly contributed  to its analgesic effect that needs further investigation  in other animal models of algesia.