Effects of maslinic acid supplementation on exercise-induced inflammation and oxidative stress in water polo athletes: A randomized, double-blind, crossover, and placebo-controlled trial

Figures & data

Table 1. Grouping condition and characteristics of participants.

Condition	Placebo		Maslinic Acid
	Before intervention	After intervention	Before intervention	After intervention
Age (years)		19.9±0.9
Height (cm)		177.2±7.6
Body weight (kg)	76.3 ± 12.5	75.5 ± 11.7	75.7 ± 11.9	75.9 ± 11.9
BMI (kg/m^2）	24.2 ± 3.0	24.1 ± 2.9	24.1 ± 2.9	24.3 ± 3.0
Muscle mass (kg)	36.0 ± 4.2	36.1 ± 4.6	36.0 ± 4.4	36.1 ± 4.6
Fat (%)	16.2 ± 5.5	15.0 ± 5.6	15.9 ± 5.2	15.9 ± 5.0

Table 2. Training schedule from Day 1 to Day 7 during intervention.

		Day 1	Day 2	Day 3	Day 4	Day 5	Day 6	Day 7
AM	Swim	Swim set (1200 m)	Swim set (1200 m)	Swim set (1200 m)	Swim set (1200 m)	Swim set (1200 m)	Game play	Testing
		Swim drills	Swim drills	Swim drills	Swim drills	Swim drills
		Medicine ball throwing	Medicine ball throwing	Medicine ball throwing	Medicine ball throwing	Medicine ball throwing
		tube pull	tube pull	tube pull	tube pull	tube pull
PM	Skill	Passing	Passing	N.A.	Passing	Passing	N.A.
		Shooting	Shooting		Shooting	Shooting
		One side game	One side game		One side game	One side game
		Match simulation	Match simulation		Match simulation	Match simulation
	Training	N.A.	Bench press	N.A.	Bentover row	N.A.	N.A.
			Side raise		Chin up
			Shoulder press		Dead lift
					Arm curl
S: Sets, R: Repetitions, RM: Repetition Maximum, BW: Body Weight
Bench press		6S × 10 R at 70 ~ 85% 1RM
Side raise		4S × 15 R at 20 kg
Shoulder press		6S × 10 R at 30 ~ 40 kg
Bentover row		6S × 10 R at 70 ~ 85% 1RM
Chin up		6S × 10 R at BW
Dead lift		4S × 10 R at 70 ~ 85% 1RM
Arm curl		6S × 10 R at ~30 kg
※Training excludes w-up.

Figure 1. Study design.

Figure 2. MA intake attenuates perceptual fatigue and muscle soreness during the one-week intervention. (a) whole body fatigue, (b) whole body muscle fatigue, (c) eye strain, (d) whole-body muscle soreness,(e) shoulder muscle soreness, (f) chest muscle soreness, (g) lower back muscle soreness and (h) femur muscle soreness. All data are expressed as the means and individual values (n = 12). Significant differences were assessed using a two-way ANOVA followed by Tukey’s multiple comparisons test. Significant differences: a: main effect of MA (P < 0.05); (a): main effect of MA (P < 0.1); b: main effect of time(P < 0.05); c: interaction of MA and time (P < 0.05); #: between placebo and MA after intervention (P < 0.05). Significant differences in AUC are shown individually.

Figure 3. MA intake inhibits the accumulation of inflammation in the blood during a one-week intervention. Levels of (A) TNF-α, (B) hs-CRP, (C) creatin and (D) creatinine concentration. All data are expressed as the means and individual values (n = 12). Paired data are connected with lines consistently across all figures where possible. Significant differences were assessed by a two-way ANOVA followed by Tukey’s multiple comparisons test. Significant differences: c: interaction of MA and time (P < 0.05); #: between placebo and MA after intervention (P < 0.05). Significant differences in the delta are shown individually.

Figure 4. MA intake inhibits oxidative stress accumulation in blood during a one-week intervention. All data are expressed as means and individual values (n = 12). Paired data are connected with lines. Significant differences were assessed by a two-way ANOVA followed by Tukey’s multiple comparisons test. Significant differences: c: interaction of MA and time (P < 0.05); #: between placebo and MA after intervention (P < 0.05). Significant differences in the delta are shown individually.

Figure 5. Inflammatory related proteins are decreased within myotubes treated with serum from MA-conditioned participants after intervention. (a) western blot band images, protein expression levels of (b) TNF-α, (c) NF-κB, and (d) COX2. All data are expressed as means and individual values (n = 12). Paired data are connected with lines consistently across in all figures. Significant differences were assessed by a two-way ANOVA followed by Tukey’s multiple comparisons test. Significant differences: b: main effect of time (P < 0.05); c: interaction of MA and time (P < 0.05); #: between placebo and MA after intervention (P < 0.05). Significant differences in the delta are shown individually.

Figure 6. Antioxidant factor-related proteins are also decreased within myotubes treated with serum from MA-conditioned participants after intervention. (a) western blot band images, protein expression levels of (b) SOD2, (c) Hmox1, (d) GPX, and (e) catalase. All data are expressed as means and individual values (n = 12). Paired data are connected with lines consistently across in all figures. Significant differences were assessed by a two-way ANOVA followed by Tukey’s multiple comparisons test. Significant differences: a: main effect of MA (P < 0.05); b: main effect of time (P < 0.05); c: interaction of MA and time (P < 0.05); #: between placebo and MA after intervention (P < 0.05). Significant differences in the delta are shown individually.

Data availability statement

The sharing of data in an open-access repository was not included in our participants consent. Thus, in accordance with standard ethical practice, data may only be available on request from the corresponding author.