Rooibos (Aspalathus linearis) extract enhances boar sperm velocity up to 96 hours of semen storage

Abstract

Rooibos (Aspalathus linearis) is a native shrub from South African fynbos and has become very popular in the last decades for its antioxidant and medicinal attributes. Several studies have shown its beneficial properties in numerous cell lines, but to date, the in vitro effects of rooibos extract on sperm cells are still unknown. In this study, boar semen was supplemented with four concentrations both of fermented and unfermented rooibos extracts during 96 h of liquid storage at 17°C. The effects of rooibos extracts on sperm velocity, membrane integrity, and acrosomal status were evaluated at 2 h, 48 h, and 96 h of semen storage. Overall our results indicate that rooibos extract enhances sperm velocity, protects the acrosome structure, and tends to preserve the membrane integrity during semen storage. Although the unfermented rooibos showed higher total polyphenol content and total antioxidant capacity than the fermented one, the latter had better effects on sperm velocity leading to, for instance, an increase of 30% in the rectilinear velocity (VSL) at 48 h compared to the control group. Taking into account the different storage times, we established a suitable range of extracts concentrations to be used in boar semen. The rooibos extract ought to be considered as a powerful and natural source of antioxidants for the preservation of boar semen.

Pharmacological Activity of Honeybush (Cyclopia intermedia) in Boar Spermatozoa during Semen Storage and under Oxidative Stress

“…We found that the suitable concentrations of honeybush for boar semen are similar to those of rooibos [12], although the latter shows a higher TPC and TAC, which is supported by other studies [2,23]. These differences in the TPC between the plant extracts suggest that the protective effects of honeybush on boar sperm may be related to its polyphenol profile, rather than the TPC per se.…”

“…Interestingly, the honeybush extract (HB3) maintained this sperm parameter unaltered until 120 h of semen storage, showing no differences compared with the CTR group at 0 h. Only the HB1 treatment (200 µg/mL) showed neither positive nor detrimental effects, when compared with the CTR samples, at the different incubation times, although some sperm parameters were enhanced but not significantly. In a previous study [12] using a related plant (rooibos) and at a similar concentration (170 µg/mL), we found a significant decrease in the percentage of motile sperm in comparison with the CTR group at 96 h of semen storage. These differences could be due to the higher TPC found in the rooibos extract.…”

“…Natural products, such as medicinal plants, could be employed as a cheap alternative to the common antioxidants used in boar semen extenders to reduce the negative effects of high levels of ROS on sperm cells. Recent studies have shown that the addition of plant extracts to extenders enhances sperm function during semen storage and in vitro fertility in boars [12,13].…”

Characterization of the Omija (Schisandra chinensis) Extract and Its Effects on the Bovine Sperm Vitality and Oxidative Profile during In Vitro Storage

“…As such, the addition of antioxidants to semen extenders has become a standard step in artificial reproduction technologies, although it often increases the final cost of semen doses [ 4 , 6 , 29 , 30 ]. As an alternative, medicinal plants and their products are increasingly recognized worldwide as an alternative source of efficient and cost-effective biomolecules that could be used as supplements during sperm storage [ 5 , 31 – 33 ].…”

Notoginsenoside R1 protects boar sperm during liquid storage at 17°C

“…Previous studies in which the extender was supplemented with different antioxidants reported different effective survival times during the liquid storage of sperms at 17°C. For example, supplementation with rooibos ( Aspalathus linearis ) yields an effective survival time of 96 hr (Ros‐Santaella & Pintus, 2017), whereas supplementation with α‐tocopherol yields an effective survival time of 72 hr (Zakošek Pipan, Mrkun, Nemec Svete, & Zrimšek, 2017). These results indicated that the addition of antioxidants was beneficial for semen quality during liquid storage at 17°C.…”