The Use of Some Polyphenols in the Modulation of Muscle Damage and Inflammation Induced by Physical Exercise: A Review

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TL;DR

This narrative review examines how six classes of polyphenols (cocoa flavanols, anthocyanins, green tea catechins, curcumin, quercetin, and resveratrol) modulate muscle damage, oxidative stress, and inflammation after strenuous exercise. Several studies show that cocoa, anthocyanins, and quercetin can increase total antioxidant capacity and attenuate markers of injury and pro-inflammatory cytokines such as IL-6, while curcumin reduced creatine kinase (CK) and tumor necrosis factor-alpha (TNF-α). The clinical significance is that polyphenol supplementation may accelerate post-exercise recovery, but results remain controversial due to low bioavailability, methodological heterogeneity, and the risk that chronic antioxidant intake could blunt beneficial training adaptations.

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**Background:** Physical exercise, particularly strenuous or unaccustomed bouts, induces skeletal muscle microdamage and a subsequent inflammatory response that is essential for tissue repair and adaptation. However, excessive muscle damage and prolonged inflammation can impair performance and delay recovery. Food bioactive compounds (FBCs), especially polyphenols, have attracted attention for their anti-inflammatory, antioxidant, and immunoregulatory properties. This narrative review synthesizes evidence on six polyphenol classes—cocoa flavanols, anthocyanins, green tea catechins, curcumin, quercetin, and resveratrol—in the context of exercise-induced muscle damage, inflammatory profile, and recovery.

**Methods:** The authors conducted a narrative review of the literature, selecting studies that investigated oral supplementation of the six polyphenol classes in conjunction with acute or chronic exercise protocols. Outcomes of interest included markers of muscle damage (creatine kinase [CK], lactate dehydrogenase [LDH]), oxidative stress (malondialdehyde [MDA], thiobarbituric acid reactive substances [TBARS], total antioxidant capacity), inflammatory cytokines (IL-6, IL-8, IL-10, TNF-α), and subjective measures of muscle soreness (visual analog scale [VAS]). The review includes both human trials and selected in vitro experiments.

**Key Results:** - **Cocoa flavanols:** Acute supplementation of 900 mg cocoa flavanols improved total plasma antioxidant capacity after a time trial (Decroix et al.). Chronic supplementation (40 g dark chocolate, 85% cocoa, for 30 days) in elite soccer players lowered CK and LDH (Cavaretta et al.). However, 10 weeks of 425 mg/day cocoa flavanols inhibited ROS formation and reduced mitochondrial biogenesis, negatively impacting aerobic adaptation (Garcia-Merino et al.). - **Anthocyanins:** Lima et al. reported that 116 mg/day anthocyanins for 9 days reduced muscle soreness (VAS) and CK at 48 h and 96 h post-downhill running. Drummer et al. found no differences in muscle soreness, IL-6, or monocyte subsets with 640 mg/day Montmorency cherry juice for 10 days. - **Green tea catechins:** Chi-Kuo et al. observed increased run time to exhaustion, improved total antioxidant capacity, and decreased CK after 250 mg/day green tea extract for 4 weeks. Jajtner et al. reported increased CK but decreased intramuscular IL-8 after 1 g/day for 28 days. Hadi et al. found decreased MDA but no differences in muscle damage indices after 450 mg/day for 6 weeks. - **Curcumin:** McFarlin et al. found a ~69% reduction in CK, ~23% reduction in TNF-α, and ~18% reduction in IL-8 after 400 mg/day for 6 days. Tanabe et al. reported ~56% lower CK at 96 h post-exercise with 300 mg curcumin. Mallard et al. observed decreased muscle soreness at 48 h and 72 h and increased IL-10 and IL-6 after 450 mg curcumin. - **Quercetin:** Bazzucchi et al. (2019) reported decreases in CK (52.7% at 48 h, 78.6% at 72 h) and LDH (19.6% at 24 h, 12.5% at 48 h, 17.5% at 72 h) after 1 g/day for 14 days. Sgrò et al. found lower IL-6 at 48 h and 72 h post-exercise. Duranti et al. showed improved GSH/GSSG ratio and decreased TBARS. - **Resveratrol:** Goulart et al. reported 10% lower lipid peroxidation, 19% lower DNA damage, and 80% lower SOD activity after 400 mL/day grape juice for 14 days in Judo athletes. Scribbans et al. found decreased PGC-1α mRNA, SIRT1 mRNA, and SOD2 mRNA after 150 mg/day resveratrol for 28 days, suggesting potential blunting of training adaptations.

**Clinical Implications:** Polyphenol supplementation shows promise for attenuating exercise-induced muscle damage and oxidative stress, with some evidence for reduced inflammatory cytokines and faster recovery of muscle function. However, the evidence is limited by small sample sizes, heterogeneous protocols, and the low bioavailability of many polyphenols (<2% for anthocyanins). Importantly, chronic antioxidant supplementation may interfere with the ROS-mediated signaling required for optimal training adaptations, as seen with cocoa flavanols and resveratrol. The synergy between multiple FBCs in whole foods (e.g., cocoa, grape juice) may produce different effects than isolated compounds. Future research should standardize dosing, duration, and outcome measures, and investigate the impact on muscle regeneration at the cellular level.