Abstract
The Moroccan flora abounds and is an important reserve of medicinal plants.
Nigella sativa
and
Lepidium sativum
are plants that are widely used in traditional medicine for their multiple therapeutic properties. The current study aims to highlight the biological activities that can justify and valorize the use of these plants. Flavonoids, total phenols, condensed tannins, and sugars were determined. The biological activities tested were antioxidant by determining the IC
50
(defined as the concentration of an antioxidant required to decrease the initial concentration by 50%; inversely related to the antioxidant capacity), hemagglutination, and hemolytic activities. Phytochemical quantification of the seed extracts indicated that the total phenol content was largely similar for both plants and in the order of 10 mg GAE (Gallic acid equivalent)/g. On the other hand,
L. sativum
seeds registered a higher content of flavonoids (3.09 ± 0.04 mg QE (quercetin equivalent)/g) as compared to
Nigella saliva
(0.258 ± 0.058). Concerning condensed tannins,
N. saliva
seeds present a higher amount with a value of 7.2 ± 0.025 mg/g as compared to
L. sativum
(1.4 ± 0.22 mg/g). Concerning the total sugar content,
L. sativum
shows a higher content (67.86 ± 0.87 mg/g) as compared to
N. sativa
(58.17 ± 0.42 mg/g); it is also richer in mucilage with a content of 240 mg as compared to 8.2 mg for
N. saliva
. Examination of the antioxidant activity using a DPPH (2.2-diphenyl 1-pycrilhydrazyl) test revealed that the EButOH (n-butanol extract) and EAE (ethyl acetate extract) extracts were the most active, with IC
50
values of 48.7 and 50.65 μg/mL for the
N. sativa
extracts and 15.7 and 52.64 μg/mL for the
L. sativum
extracts, respectively. The results of the hemagglutination activity of the different extracts of the two plants prepared in the PBS (phosphate-buffered saline) medium showed significant agglutination for the
L. sativum
extract (1/50) compared to the
N. sativa
extract (1/20). An evaluation of the hemolytic effect of the crude extract of the studied seeds on erythrocytes isolated from rat blood incubated in PBS buffer compared to the total hemolysis induced by distilled water showed a hemolysis rate of 54% for
Nigella sativa
and 34% for
L. sativum
. In conclusion, the two plants studied in the current work exhibited high antioxidant potential, which could explain their beneficial properties.