Abstract:
In the present research project, black cumin seed oil (fixed & essential) was
characterized, used in cookies formulation, and tested for its nutraceutical potential
against oxidative stress, diabetes and dyslipidemia through rat modeling studies.
Compositional analysis revealed that fixed oil is a rich source of polyunsaturated
fatty acids, tocopherols and to some extent thymoquinone, whilst essential oil was
abundant in bioactive molecules like thymoquinone, p-cymene, carvacrol, α-thujene
and thymol. Both oils inhibited in vitro lipid peroxidation and scavenged DPPH
radicals significantly. Afterwards, fixed and essential oils were added in the cookies
at varying levels to enrich the formulation. The functional ingredients of the
respective oils improved the oxidative stability of the cookies with better hedonic
response over control. Considering the results of characterization and product
development; fixed oil @ 4% and essential oil @ 0.3% were selected for further use in
efficacy study. The experimental rats modeling comprised of four segments
including normal, oxidative stressed, diabetic and hypercholesterolemic Sprague
Dawley rats. Initial trials were conducted in normal rats; indicated that diets
prepared with fixed and essential oils hold hypoglycemic and hypocholesterolemic
perspectives. Moreover, reduction in oxidative damage, improvements in
antioxidant status and modulation of hepatic antioxidant enzymes were also
observed in groups fed on diet containing fixed and essential oils. In oxidative
stressed rats, serum MDA and conjugated dienes levels were significantly reduced
by 20.58 and 51.62% in black cumin fixed and essential oils groups, respectively.
Moreover, experimental diets enhanced the total antioxidant capacity and
antioxidant status as compared to the control. Similarly, activities of hepatic enzyme
and parameters associated with immunity were modulated significantly. Allied
discrepancies like elevated cholesterol and glucose during stress were markedly
reduced as a function of black cumin fixed and essential oils diets however, essential
oil gave better performance and can be used as safeguard against the menace. In the
third section, streptozotocin injection was used to induce diabetes mellitus in rats.
There observed decrease of 4.10 and 10.23% for glucose in fixed and essential
groups, respectively, as compared to 33.21% rise in control. Furthermore, insulin
level decreased significantly in control group i.e. 51.72% as compared to increasing
trend in fixed and essential oils groups i.e. 5.63 and 10.43%, respectively, indicated
that experimental diets hold insulinotropic potential. It was noted that management
of antioxidant status and lipid profile were cardinal in controlling diabetic
complications.
Finally,
efficacy
trials
were
conducted
involving
hypercholesterolemic rats. In control group, momentous increase in serum
cholesterol, triglycerides and LDL levels was observed, whereas fixed and essential
oils attenuated the cholesterol 10.70 & 5.44%, triglycerides 19.35 & 5.45% and LDL
15.38 & 12.79%, respectively. Improvements in antioxidant status and reduced
oxidative damage were also observed. Both oils reduced the serum glucose
significantly by enhancing insulin secretion. Correlation matrix indicated significant
association among indices of oxidative damage, lipid profile and glucose response.
From the present study, it is deduced that black cumin fixed and essential oils can be
supplemented in food products for the management of these maladies.