Abstract:
The basic aim of this placebo control study was to investigate the effects of three
different preparations of Nigella sativa especially on glucose and lipid metabolism in
type 2 diabetes mellitus (DM2) patients (group-A); however normal individuals (group-
B) was also studied. Both groups were treated with N. sativa Seed Powder (NsP), N.
sativa Aqueous Extract (NsE) and N. sativa Oil (NsO), in addition to a placebo in
phases 1, 2 and 3 respectively. Each phase was of 80 days (40 days of treatment with N.
sativa preparation followed by 40 days of placebo administration). Levels of 0 day
were taken as base line (concurrent control) in each phase. Fasting blood levels of
glucose, insulin, total cholesterol (TC), LDL & HDL cholesterols, triglycerides (TG),
total leukocyte & platelet counts, hepatic profile and blood urea were determined in
subjects of both groups on 0, 40 and 80 th day of each phase of the study. In phase-1 a
highly significant fall in fasting blood glucose, TC, LDL cholesterol and TG while an
increase in insulin and HDL was observed in group-A after treatment with NsP as
compared to concurrent control. These levels significantly reversed at the end of
placebo except the HDL cholesterol. Almost similar results were obtained in subjects of
group-B. In phase-2 although a decrease in glucose and increase in insulin levels was
observed in group-A after treatment with NsE; which reversed after the placebo yet the
changes were not significant. However a significant fall was observed in TC and TG
levels of diabetics after NsE treatment; which reversed after the placebo significantly in
TG but insignificantly in TC. In group B, results regarding glucose and insulin levels
were similar to that of group-A of this phase. Concerning lipid profile, a significant fall
in TG and insignificant decrease in TC and LDL cholesterol was observed after NsE
treatment. The changes reversed after the placebo, significantly in TG and LDL
cholesterol but insignificantly in TC. In phase-3, a significant fall in fasting blood
glucose and a rise in insulin levels was observed in group-A after treatment with NsO2
as compared to concurrent control levels. A significant decrease in LDL & increase in
HDL was observed while TC remained statistically unchanged; however a significant
increase was also recorded in TG after NsO treatment. LDL and TG levels reversed
significantly, while no significant change was observed in HDL and TC levels after the
placebo. Subjects of group-B behaved similar to group-A, as for glucose and insulin are
concerned. Regarding lipids, a decrease in LDL cholesterol (significant) and TC
(insignificant) while increase in HDL cholesterol and TG (insignificant) was observed
in group-B after the use of NsO. LDL and TC increased significantly after the placebo
while no significant change was recorded in HDL cholesterol and TG. Total leukocyte
and platelet counts remained statistically unchanged in both groups A and B, when
treated with NsP, NsE, NsO or administered with placeboes in phases 1, 2 and 3
respectively as compared to their base line levels Similarly no unpleasant effect of any
of the N. sativa preparation was observed regarding hepatic profile, blood urea and the
subjective feelings of the diabetic and normal individuals. In the light of foregoing facts
it can safely be concluded that all preparations of N. sativa had some or more
antidiabetic effect. However keeping in view the overall performance, NsP was found
more effective. Further large scale human studies with different dose schedules of NsP
are recommended.