Chemical Composition Analysis Using HPLC-UV/GC-MS and Inhibitory Activity of Different Nigella sativa Fractions on Pancreatic α-Amylase and Intestinal Glucose Absorption

Abstract

Nigella sativa (NS) is a well-known plant for its various benefits and multiuse in traditional medicine. This study is aimed at investigating the chemical composition of the different NS fractions by using GC-MS for the esterified fatty acids or HPLC-UV for organic fraction and at evaluating the inhibitory effect on pancreatic α-amylase (in vitro, in vivo) and intestinal glucose absorption. Among all the investigated fractions, it was shown that they are rich with different molecules of great interest. The n-hexane fraction was characterized by the presence of linoleic acid (44.65%), palmitic acid (16.32%), stearic acid (14.60%), and thymoquinone (8.7%), while among the identified peaks in EtOH fraction we found catechin (89.03 mg/100 g DW), rutin (6.46 mg/100 g DW), and kaempferol (0.032 mg/100 g DW). The MeOH fraction was distinguished with the presence of gallic acid (19.91 mg/100 g DW), catechin (13.79 mg/100 g DW), and rutin (21.07 mg/100 g DW). Finally, the aqueous fraction was marked by the existence of different molecules; among them, we mention salicylic acid (32.26 mg/100 g DW), rutin (21.46 mg/100 g DW), and vanillic acid (3.81 mg/100 g DW). Concerning the inhibitory effect on pancreatic α-amylase, it was found that in the in vitro study, the best IC50 registered were those of EtOH (0.25 mg/ml), MeOH (0.10 mg/ml), aqueous (0.031 mg/ml), and n-hexane fraction (0.76 mg/ml), while in the in vivo study an important inhibition of α-amylase in normal and diabetic rats was observed. Finally, the percentage of intestinal glucose absorption was evaluated for all tested extracts and it was ranging from 24.82 to 60.12%. The results of the present study showed that the NS seed fractions exert an interesting inhibitory effect of α-amylase and intestinal glucose absorption activity which could be associated with the existent bioactive compounds. Indeed, these compounds can be used as antidiabetic agents because of their nontoxic effect and high efficacy.

Nigella sativa L. Phytochemistry and Pharmacological Activities: A Review (2019–2021)

“…The results obtained show that this extract can decrease fasting blood glucose [ 95 ]. As reported by Dalli et al [ 19 ], the different fractions obtained by the soxhlet apparatus (Aqueous, MeOH, EtOH, Hex) induced important inhibition not only for the α-amylase (in vitro) but also for the intestinal glucose absorption (in situ) ( Table 6 ). The combination of TQ and metformin (50/200 mg/kg) caused a decrease in blood glucose level by 41.3%.…”

“…Inhibition of peroxidase activity is another benefit of flavonoids, which allows the prevention from oxygen reactive species [ 18 ]. Among the extracted phenolic compounds from the NS seeds ( Figure 2 ), we mention gallic acid, ferulic acid, vanillic acid, p-coumaric acid, chlorogenic acid, catechin, quercetin, apigenin, rutin, nigelflavonoside B, and flavone [ 19 , 20 ].…”

“…The black cumin seeds were found to contain crude fiber, minerals (Na, Cu, Zn, P, and Ca), and vitamins such as thiamine, niacin and folic acid [ 26 ]. Furthermore, the NS possesses different types of fatty acids that were determined using the GC-MS technique [ 19 , 27 ] ( Figure 5 ). The linoleic acid (55.6%) was among the most abundant fatty acids present in the NS seeds, followed by oleic acid (23.4%), and palmitic acid (12.5%).…”

“…While the intraperitoneal administration gave an LD 50 of 2.06 mL/kg body weight [ 113 ]. The acute toxicity of the different fractions obtained using the soxhlet apparatus showed no toxic effect even at higher doses (5 g/kg) [ 19 ]. Meanwhile, TQ administration to albino mice at a dose of 870 mg/kg body weight was highly toxic.…”

Loaded n-Hydroxyapatite/SSG 3D Scaffolds as a Drug Delivery System of Nigella sativa Fractions for the Management of Local Antibacterial Infections

“…It was also noted that black cumin has a large spectrum of pharmacological activities. It was found that the plant extracts exert an antibacterial [ 24 ], antifungal [ 25 ], antidiabetic [ 26 ], immunomodulatory [ 27 ], and analgesic effect [ 28 ].…”