title: The single and synergistic effects of the major tea components caffeine, epigallocatechin-3-gallate and L-theanine on rat sperm viability.
abstract: Caffeine, epigallocatechin-3-gallate (EGCG) and L-theanine are the major components of tea (Camellia sinensis L.) and the main representatives of the classes of methylxanthines, catechins and free amino acids present in this beverage. There are many studies reporting tea's health benefits, however it is not clear if those effects are mediated by a single component or a synergistic action. This study aimed to evaluate the individual and synergistic effects of tea's major components on rat epididymal spermatozoa survival and oxidative profile during 3-day storage at room temperature (RT). For that, spermatozoa were incubated with caffeine (71 μg mL(-1)), EGCG (82 μg mL(-1)), or L-theanine (19 μg mL(-1)), alone or in combination. Spermatozoa viability was assessed by the eosin-nigrosin staining technique. The oxidative profile was established by evaluating the levels of carbonyl groups, protein nitration and lipid peroxidation. Supplementation of sperm storage medium with the three compounds together improved sperm viability, after 24, 48 and 72 h of incubation, relative to the control and the groups incubated with each component individually. However, at the end of the 72 h of incubation, there was an increase in protein oxidation in the group exposed to the three compounds, illustrating that the combined treatment triggers different alterations in sperm proteins during their maturational process in the epididymis. This study highlights the importance of the synergism between tea components for the beneficial effects usually attributed to this beverage, particularly in sperm storage at RT.
authors.affiliation: Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal. bmcms@gmail.com and Department of Microscopy, Laboratory of Cell Biology, Institute of Biomedical Sciences Abel Salazar (ICBAS) and Unit for Multidisciplinary Research in Biomedicine (UMIB), University of Porto, 4050-313 Porto, Portugal.
authors.forename: Tânia R
authors.initials: TR
authors.lastname: Dias
authors.affiliation: Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal. bmcms@gmail.com.
authors.forename: Marco G
authors.initials: MG
authors.lastname: Alves
authors.affiliation: LAQV/REQUIMTE - Laboratory of Bromatology and Hydrology, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal.
authors.forename: Susana
authors.initials: S
authors.lastname: Casal
authors.affiliation: Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal. bmcms@gmail.com.
authors.forename: Branca M
authors.initials: BM
authors.lastname: Silva
authors.affiliation: Department of Microscopy, Laboratory of Cell Biology, Institute of Biomedical Sciences Abel Salazar (ICBAS) and Unit for Multidisciplinary Research in Biomedicine (UMIB), University of Porto, 4050-313 Porto, Portugal and I3S - Institute for Innovation and Health Research, University of Porto, 4050-313 Porto, Portugal.
authors.forename: Pedro F
authors.initials: PF
authors.lastname: Oliveira
mesh_terms: D000818:Animals; D002110:Caffeine / Q000494:pharmacology*; D028241:Camellia sinensis / Q000737:chemistry; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D005971:Glutamates / Q000494:pharmacology*; D008297:Male; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013094:Spermatozoa / Q000166:cytology* / Q000187:drug effects*
chemical_list: D005971:Glutamates; D010936:Plant Extracts; D002110:Caffeine; C026166:theanine; D002392:Catechin; C045651:epigallocatechin gallate