Comparative study of the effect of green and roasted water extracts of mate (Ilex paraguariensis) on glucosyltransferase activity of Streptococcus mutans

Figures & data

Figure 1.  Effect of roast and green mate extracts on the activity of the glucosyltransferase (GTF) of S. mutans. The GTF activity was calculated by considering the control as having maximum GTF activity (100%). The results are expressed as the mean ± standard deviation (SD) of three determinations. *Significant difference at the level of P < 0.05 as compared with the control.

Figure 2.  Effect of the time of incubation of the crude glucosyltransferase (GTF) extract with the roast (•) and green (○) mate extracts (10 mg/mL) on the activity of the GTF of S. mutans. The results are expressed as the mean ± standard deviation (SD) of three determinations.

Table 1.  Kinetic parameters of the inhibitory effect of green and roast mate extracts on the activity of glucosyltransferase (GTF) and growth of S. mutans.

Treatment	Concentration (mg/mL)	Km (mM)	Vmax^a	Ki (mM)	MIC^b
Control		20.5 ± 0.8^a	25.2 ± 0.4^a
Roast mate extract	8	31.3 ± 0.4^b	25.8 ± 1.2^a	15.1^a	(−)
	16	43.0 ± 1.3^c	23.0 ± 0.6^a	14.5^a	(+)
Green mate extract	8	25.7 ± 0.6^d	24.6 ± 2.1^a	34.5^b	(−)
	16	29.8 ± 0.5^b,e	23.4 ± 1.7^a	35.1^b	(−)

Results are expressed as the mean ± standard deviation (SD) of three determinations.

Means within a column with different superscript letters are significantly different P ≤ 0.05.

^aV_max: μmol glucose per minute.

^bMinimum inhibitory concentration (MIC): (+) and (−) when inhibited or not inhibited growth of S. mutans.

Figure 3.  Lineweaver–Burk double reciprocal plot of the glucosyltransferase (GTF) activity. V is the initial velocity and [S] is the concentration of sucrose. The values are shown for the absence (▪), 8 mg/mL (•) and 16 mg/mL (▴) of roast mate extract. The values are means of triplicate determinations and the error bars indicate SD (n = 3).

Table 2.  Phenolic compounds identified and quantified by UPLC-MS in green and roast mate.^a

Compounds	m/z	Green mate extract (μg/mL)	Roasted mate extract (μg/mL)
Caffeic acid	179	3.9 ± 0.1	5.1 ± 0.3
Quinic acid	191	2.8 ± 0.3	25.1 ± 0.1
Caffeine	194	113.6 ± 3.7	98.5 ± 1.3
Caffeoylshikimic acid isomers	335	5.5 ± 0.7	36.0 ± 0.5
Caffeoyl glucose	341	180.0 ± 8.9	34.4 ± 2.5
Caffeoylquinic acid isomers	353	335.4 ± 4.5	215.7 ± 3.5
Feruloylquinic acid	367	33.1 ± 0.2	21.7 ± 0.2
Dicaffeoylshikimic acid isomers	497	1.7 ± 0.1	4.6 ± 0.3
Dicaffeoylquinic acid isomers	515	1414.9 ± 182.8	878.3 ± 96.7
Rutin	609	937.7 ± 80.6	145.1 ± 4.3

^aResults are expressed as the mean ± standard deviation (SD) of three determinations. All differences between the roasted and green mates are significantly different P < 0.05 (two-tailed unpaired t-test).

^bCaffeoylquinic acid isomers: 4-O-caffeoylquinic acid (crypto-chlorogenic acid), 5-O-caffeoylquinic acid (neo-chlorogenic acid), 3,4-dicaffeoylquinic acid and 3,5-dicaffeoylquinic acid.

Figure 4.  ESI-MS fingerprints of water extracts of: (A) green mate and (B) roasted mate. For the compounds identified, see Table 2.

Table 3.  Total phenolic and flavonoid contents of the aqueous extracts of green and roasted mate.

Aqueous extract	Total phenolics (mg GAE/g extract)	Total flavonoids (mg CE/g extract)
Roast mate	98.7 ± 4.1^a	74.6 ± 4.7^a
Green mate	154.0 ± 8.4^b	125.9 ± 6.3^b

Means within a column with different superscript letters are significantly different P ≤ 0.05.

Table 4.  Effects of several selected polyphenols on the glucosyltransferase (GTF) activity of S. mutans.

Compounds and concentration (μM)	Structure	% Inhibition*
Caffeine (purine alkaloids)
125		3.8 ± 2.5
250		7.5 ± 3.1
500		7.8 ± 1.2
Caffeic acid (cinnamic acid derivatives)
125		5.3 ± 3.1
250		4.7 ± 3.4
500		8.8 ± 5.1
Chlorogenic acid (caffeoylquinic acid derivatives)
125		23.4 ± 2.4
250		26.6 ± 4.1
500		34.7 ± 4.9
5-O-Caffeoylshikimic acid
125		21.5 ± 3.2
250		32.4 ± 6.1
500		41.1 ± 3.5
Quinic acid
125		4.7 ± 1.7
250		9.1 ± 3.5
500		10.9 ± 3.2
Rutin (flavonols)
125		42.3 ± 4.2
250		51.7 ± 3.9
500		68.8 ± 5.5

*Results are expressed as the mean ± standard deviation (SD) of four determinations. Percent inhibition was calculated considering the control as having maximum GTF activity (100%).