Investigation of a wild pear species (Pyrus elaeagnifolia subsp. Elaeagnifolia Pallas) from Antalya, Turkey: polyphenol oxidase properties and anti-xanthine oxidase, anti-urease, and antioxidant activity

Figures & data

Table 1. Substrate specificity of the PePPO.

Substrate	Type of phenolic compound	Relative activity (%)
4-Methylcatechol	Dihydroxy	100
Catechol	Dihydroxy	65.01 ± 0.92
3-(3,4-Dihydroxyphenyl) propionic acid (DHPPA)	Dihydroxy	23.74 ± 0.25
Gallic acid	Trihydroxy	25.79 ± 0.71
L-3,4-Dihydroxyphenylalanine (L-DOPA)	Dihydroxy	12.82 ± 0.12
L-Tyrosine	Monohydroxy	1.04 ± 0.03
3-(4-Hydroxyphenyl) propionic acid (PHPPA)	Monohydroxy	0.74 ± 0.07

Figure 1. Gel revealed by incubating with 100 mM of L-Dopa as a substrate of polyphenol oxidase.

Figure 2. (a) pH-activity profile for PePPO; (b) pH stability of PePPO; (c) Optimum temperature of PePPO; and (d) Thermal stability of PePPO.

Table 2. The IC₅₀ values of some inhibitors.

Inhibitor	IC50 (mM)
Sodium metabisulphite	0.0185 ± 0.0013
Ascorbic acid	0.0036 ± 0.0002
Sodium azide	4.0231 ± 0.0112
Benzoic acid	0.4653 ± 0.0074

Table 3. Effect of various metal ions on PePPO activity.

Metal ion (1 mM)	Residual activity (%)	Metal ion (1 mM)	Residual activity (%)
None	100	Mg^2^+	106.3
Ca^2^+	101.5	Co^2^+	155.3
Mn^2^+	126.2	Sr^2^+	97.1
Ba^2^+	106.8	Cd^2^+	93.7
Na^1^+	91.3	Ni^2^+	151.9
Fe^2^+	70.4	Zn^2^+	155.3
Hg^2^+	40.3	Al^3^+	112.6
K^1^+	126.2

Table 4. Antioxidant activity values of AePep.

	CUPRAC method	Total phenolic content	DPPH method	ABTS method
Sample	mg TEAC/g FW	mg GAE/g FW	SC50 (mg/mL)	SC50 (mg/mL)
^aAePep	104.05 ± 2.47	4.98 ± 0.06	3.49 ± 0.07	5.01 ± 0.03
^bBHT	—	—	13.87 ± 0.09	12.20 ± 0.06

Results are expressed as the mean ± SD in triplicate.

^aIC₅₀ values were given in terms of mg/mL.

^bIC₅₀ values were given in terms of µg/mL.

Table 5. Each enzyme IC₅₀ and % inhibition values of the AePep samples.

	Inhibition XO activity %		Inhibition urease activity %
Sample	(62.50 mg/mL)	IC50	(10.94 mg/mL)	IC50
^aAePep	98.51 ± 0.69	10.75 ± 0.11	99.93 ± 0.11	0.97 ± 0.03
^bAllopurinol (7.81 µg/mL)	97.89 ± 0.43	0.52 ± 0.02
^bThiourea (50 µg/mL)			85.67 ± 0.17	12.09 ± 0.13

IC₅₀ values and inhibition activities are expressed as the mean ± SD in triplicate.

^aIC₅₀ values were given in terms of mg/mL.

^bIC₅₀ values were given in terms of µg/mL.