br Results br Qualitative assessment br The aerial parts
3.1. Qualitative assessment
The aerial parts of the four C. curetum solvent fractions contained a wide range of secondary metabolites, as shown in Table 1. The results show that the aqueous fraction was rich in secondary and primary metabolites including flavonoids, tannins, phenols, alkaloids, saponins and cardiac glycosides, protein, starch and reducing sugars. In addition, the methanol fraction contained flavonoids, terpenoids, tannins, phe-nols, alkaloids and reducing sugars. The acetone and hexane fractions contained only cardiac glycosides, alkaloids, terpenoids and steroids.
The qualitative results are expressed as (+) for the presence and (−) for the absence of these phytochemical classes
3.2. Quantitative analysis of TP, TF and TT
From the gallic 2303-35-7 calibration curve of (Fig. 1), the following equation was obtained and used to estimate the total phenol contents in the four C. curetum fractions.
where y is absorbance at 765 nm and x is the total phenol content of the plant fraction.
According to the standard calibration curve of Rutin, as presented in
Fig. 1. Standard calibration curve of Gallic acid.
Fig. 2. Standard calibration curve of Rutin.
According to the standard calibration curve of Catechin, as shown in Fig. 3, the equation y = 0.0011x + 0.0023, R2 = 0.991 was used to estimated total tannins contents in the four fractions, where Y is the absorbance at 500 nm and X is the total tannin content in the plant fraction.
In summary, Table 2 shows the quantitative test results of the C.
curetum hexane, acetone, methanol and aqueous fractions.
3.3. α-amylase inhibitory activity
Table 3 and Fig. 4 show the α-amylase inhibitory activities of the C. curetum hexane, acetone, methanol and aqueous fractions. The aqueous and methanol fractions showed strong anti-amylase activity compared with the reference anti-diabetic drug Acarbose. The IC50 values were 21.37 ± 0.31 μg/mL and 30.2 ± 0.42 μg/mL, respectively, while the IC50 of the anti-amylase compound Acarbose was 28.18 ± 0.42 μg/mL.
3.4. α-glucosidase inhibitory activity
Table 4 and Fig. 5 depict the α-glucosidase inhibitory activity and IC50 values of the C. curetum hexane, acetone, methanol and aqueous fractions in addition to the antidiabetic drug Acarbose. The results show that the C. curetum methanolic fraction had potent α-glucosidase in-hibitory activity with an IC50 value of 27.54 ± 4.28 μg/mL.
Fig. 3. Standard calibration curve of Catechin.
Table 2 Quantitative phenol, tannin and flavonoid contents.
Fractions Total flavonoids contents, mg of QUE/g of plant fraction, ± SD
Total phenol contents, mg of GAE/g of plant fraction, ± SD
Total Tannin contents, mg of CAE/g of plant fraction, ± SD
3.5. Anti-lipase potential
Porcine pancreatic lipase inhibitory activity assay was utilised to evaluate the anti-lipase activity of the C. curetum hexane, acetone, methanol and aqueous fractions in addition to the reference anti-lipase drug Orlistat, which is used as an anti-obesity agent. The porcine pancreatic lipase inhibitory activities and the IC50 values are shown in Table 5 and Fig. 6. The results indicate that the hexane fraction had the highest anti-lipase activity compared with Orlistat and had an IC50 value of 154.8 ± 1.86 μg/mL. Orlistat had an IC50 value of 12.3 ± 0.35 μg/mL, while the other fractions did not show any anti-lipase activity.
3.6. Cytotoxic eﬀect of C. Curetum fractions
Herbal products have been utilized for therapeutic purposes for time
Fig. 4. α-amylase inhibitory activity of the C. curetum hexane, acetone, me-thanol and aqueous fractions in addition to Acarbose.
immemorial, and to this day, many important and familiar medica-ments originate from plants . Throughout the phytochemical screening outcomes, it was observed that the polar fractions (methanol and aqueous) were rich in polyphenols. On the other hand, the hexane and acetone fractions contained steroidal metabolites. Moreover, the quantitative phytochemical tests results revealed the absence of phe-nolic, flavonoid and tannin contents in the hexane and acetone frac-tions, while the aqueous fraction contained the highest contents of flavonoids, tannins, and phenols.
Diabetes mellitus is a chronic disorder that becomes a dangerous global health problem and considered one of the main risks of neuro-pathy, stroke, nephropathy, retinopathy, and cataracts. Some natural and synthetic products may be used as potent inhibitors of carbohy-drate degrading enzymes such as α-amylase and α-glucosidase to de-crease the risk of diabetes, especially type 2 diabetes and its serious complications.