Enzymatically modified isoquercitrin supplementation intensifies plantaris muscle fiber hypertrophy in functionally overloaded mice.

BACKGROUND: Enzymatically modified isoquercitrin (EMIQ) is produced from rutin using enzymatic hydrolysis followed by treatment with glycosyltransferase in the presence of dextrin to add glucose residues. EMIQ is absorbed in the same way as quercetin, a powerful antioxidant reported to prevent disused muscle atrophy by targeting mitochondria and to have ergogenic effects. The present study investigated the effect of EMIQ on skeletal muscle hypertrophy induced by functional overload. METHODS: In Study 1, 6-week-old ICR male mice were divided into 4 groups: sham-operated control, sham-operated EMIQ, overload-operated control, and overload-operated EMIQ groups. In Study 2, mice were divided into 3 groups: overload-operated whey control, overload-operated whey/EMIQ (low dose), and overload-operated whey/EMIQ (high dose) groups. The functional overload of the plantaris muscle was induced by ablation of the synergist (gastrocnemius and soleus) muscles. EMIQ and whey protein were administered with food. Three weeks after the operation, the cross-sectional area and minimal fiber diameter of the plantaris muscle fibers were measured. RESULTS: In Study 1, functional overload increased the cross-sectional area and minimal fiber diameter of the plantaris muscle. EMIQ supplementation significantly increased the cross-sectional area and minimal fiber diameter of the plantaris muscle in both the sham-operated and overload-operated groups. In Study 2, EMIQ supplementation combined with whey protein administration significantly increased the cross-sectional area and minimal fiber diameter of the plantaris muscle. CONCLUSION: EMIQ, even when administered as an addition to whey protein supplementation, significantly intensified the fiber hypertrophy of the plantaris muscle in functionally overloaded mice. EMIQ supplementation also induced fiber hypertrophy of the plantaris in sham-operated mice.

Administration of Piceatannol Complexed with α-Cyclodextrin Improves Its Absorption in Rats.

Piceatannol is polyphenolic antioxidant found in passion fruit (Passiflora edulis) seeds. The aim of this study was to improve the absorption of piceatannol using α-cyclodextrin (αCD). The solubility of piceatannol in neutral and acidic solutions increased in an αCD concentration-dependent manner. The maximum plasma concentration of intact piceatannol and the time-to-maximum plasma concentration of O-methylated piceatannol metabolites increased in rats administered αCD-piceatannol inclusion complexes (PICs). Administering the αCD inclusion complexes significantly increased the area under the concentration-time curve of total stilbene derivatives (0-3 h) in terms of the total amount of intact piceatannol, O-methylated piceatannol, conjugated piceatannol, and isorhapontigenin. Gastrointestinal ligation experiments demonstrated that substantially higher levels of piceatannol metabolites were present in the lower intestine (the ileum) at 1 h postintragastric αCD-PICs administration as compared to those observed following piceatannol administration only. These results suggested that αCD enhanced piceatannol movement and absorption in the small intestine.

Comparison of (-)-epigallocatechin-3-O-gallate (EGCG) and O-methyl EGCG bioavailability in rats.

(-)-Epigallocatechin-3-O-(3-O-methyl)gallate (EGCG3″Me) and (-)-epigallocatechin-3-O-(4-O-methyl)gallate (EGCG4″Me) are O-methyl derivatives of (-)-epigallocatechin-3-O-gallate (EGCG) present in tea cultivars such as Benifuuki. Although O-methyl EGCGs have various bioactivities, their bioavailabilities have not been determined. In this study, we compared the bioavailability of EGCG and O-methyl EGCGs in rats, and clarified the pharmacokinetics of O-methyl EGCGs. Following oral administration (100 mg/kg), the areas under the concentration-time curves (AUCs) for EGCG, EGCG3″Me, and EGCG4″Me were 39.6 ± 14.2 µg·h/L, 317.2 ± 43.7 µg·h/L, and 51.9 ± 11.0 µg·h/L, respectively. The AUC after intravenous administration (10 mg/kg) was 2772 ± 480 µg·h/L for EGCG, 8209 ± 549 µg·h/L for EGCG3″Me, and 2465 ± 262 µg·h/L for EGCG4″Me. The bioavailability of EGCG3″Me (0.38%) was the highest (EGCG: 0.14% and EGCG4″Me: 0.21%). The distribution volume of EGCG3″Me (0.26 ± 0.02 L/kg) was the lowest (EGCG: 0.94 ± 0.16 L/kg and EGCG4″Me: 0.93 ± 0.14 L/kg). These results suggested that the higher AUC of EGCG3″Me after oral administration was related to its high bioavailability and low distribution volume. These findings supported the stronger bioactivity of EGCG3″Me in vivo.