Inhibition of key enzymes linked to type 2 diabetes and sodium nitroprusside-induced lipid peroxidation in rat pancreas by water extractable phytochemicals from some tropical spices

Figures & data

Table 1.  Description of some commonly consumed Nigerian species.

Sample & code	Common name	Part used
Xylopia aethiopica (XA)	African/ethiopia pepper	Fruit
Piper guineense (PG)	Ashanti/black pepper	Seed
Aframomum melegueta (AM)	Alligator pepper or grains of paradise	Seed
Monodora myristica (MM)	African nutmeg	Seed
Aframomum danielli (AD)	Bastered melegueta	Seed
Syzygium aromaticum (SA)	Clove	Bud

Figure 1.  α-Amylase inhibitory activities of aqueous extracts of some tropical spices. Values represent mean ± standard deviation, n = 3. AD, A. danielli; AM, A. melegueta; MM, M. myristica; PG, P. guineense; SA, S. aromaticum; XA, X. aethiopica.

Table 2.  EC₅₀ /IC₅₀ values of DPPH radical scavenging ability, α-amylase and α-glucosidase inhibitory activity of aqueous extract of some tropical spices

Samples	EC50 of DPPH radical scavenging ability (mg/mL)	IC50 of α-amylase inhibitory activity (mg/mL)	IC50 of α-glucosidase inhibitory activity (mg/mL)
XA	16.77 ± 2.10	2.81 ± 0.79	2.57 ± 1.15
PG	17.05 ± 3.70	3.23 ± 1.05	2.49 ± 0.96
MM	16.88 ± 1.70	3.80 ± 1.00	3.52 ± 1.22
AM	17.38 ± 2.00	4.83 ± 0.56	2.14 ± 1.08
AD	16.39 ± 2.50	4.30 ± 1.04	2.02 ± 1.13
SA	15.47 ± 2.25	3.34 ± 0.95	2.69 ± 0.75

Values represent mean ± standard deviation, number of samples n = 3.

AD, A. danielli; AM, A. melegueta; MM, M. myristica; PG, P. guineense; SA, S. aromaticum; XA, X. aethiopica.

Figure 2.  α-Glucosidase inhibitory activities of aqueous extracts of some tropical spices. Values represent mean ± standard deviation, n = 3. AD, A. danielli; AM, A. melegueta; MM, M. myristica; PG, P. guineense; SA, S. aromaticum; XA, X. aethiopica.

Figure 3.  Inhibition of sodium nitroprusside (SNP) induced lipid peroxidation in rat pancreas by aqueous extracts of some commonly consumed spices. Values represent mean ± standard deviation, n = 3; Basal = lipid peroxidation without SNP as prooxidants and no spice extracts; Induced = Lipid peroxidation with SNP as prooxidants and no spice extracts. AD, A. danielli; AM, A. melegueta; MM, M. myristica; PG, P. guineense; SA, S. aromaticum; XA, X. aethiopica.

Figure 4.  DPPH free radical scavenging ability of aqueous extract of some tropical spices. Values represent mean ± standard deviation, n = 3. AD, A. danielli; AM, A. melegueta; MM, M. myristica; PG, P. guineense; SA, S. aromaticum; XA, X. aethiopica.

Table 3.  Phytochemical constituents of some tropical spices.

Spices	Alkaloids	Saponins	Tannins	Phlobatanins	Anthraquinones	Flavonoids	Cardiac glycosides
							Legal	Liebamans	Salkowki	Keller killani
XA	−	+	+	−	−	+	+	+	+	+
PG	−	+	−	−	−	+	+	−	+	+
MM	−	−	−	−	−	+	+	−	+	−
AM	−	+	−	−	−	+	+	−	+	+
AD	−	+	−	−	−	+	+	−	+	−
SA	−	+	+	+	+	+	+	−	+	+

+ signifies present; - signifies absent.

AD, A. danielli; AM, A. melegueta; MM, M. myristica; PG, P. guineense; SA, S. aromaticum; XA, X. aethiopica.

Table 4.  Phenolic distribution of some tropical spices (mg/g).

Sample	Total phenol	Total flavonoid
Xylopia aethiopica (XA)	1.38 ± 0.20	0.24 ± 0.03
Piper guineense (PG)	1.25 ± 0.12	0.41 ± 0.05
Monodora myristica (MM)	0.60 ± 0.09	0.21 ± 0.05
Aframomum melegueta (AM)	2.28 ± 0.02	0.55 ± 0.00
Aframomum danielli (AD)	1.65 ± 0.05	0.29 ± 0.07
Syzygium aromaticum (SA)	0.88 ± 0.30	0.26 ± 0.07

Note: + signifies present; − signifies absent.