Essential oils rich in monoterpenes are unsuitable as additives to boar semen extender

Abstract

Despite the development of efficient boar semen extenders, there is still room for improvement of new formulas using new molecules that could increase fertilisation outcomes and substitute cryoprotectants and antibiotics. The goal of this work was to evaluate if the essential oils from the leaves of Myrrhinium atropurpureum and Cymbopogon citratus are suitable as additives in boar semen extender. The major compounds found in the essential oils from M. atropurpureum were 1,8-cineole (37.37%) and terpinolene (19.18%); and geranial (49.8%) and neral (33.24%) in essential oil of C. citratus. The addition of 1% and 0.1% of both essential oils to extended semen had immediate spermicidal effects (p < 0.05). Lower concentrations were tested and no cytotoxic effect was observed when M. atropurpureum essential oil was added at 0.001%. Differently, essential oil from C. citratus reduced sperm motility, membrane functionality and integrity and mitochondrial membrane potential even in concentrations as low as 0.001%. Also, addition of essential oils in low concentrations had no inhibitory effect against Escherichia coli and Pseudomonas aeruginosa growth. We conclude that the essential oils from C. citratus and M. atropurpureum, rich in monoterpenes, are cytotoxic to swine spermatozoa, therefore unsuitable as semen extender additives.

Three chemotypes of thyme (Thymus vulgaris L.) essential oil and their main compounds affect differently the IL-6 and TNFα cytokine secretions of BV-2 microglia by modulating the NF-κB and C/EBPβ signalling pathways

“…According to the GC-MS, geraniol (54.9%), thujanol (33.9%) and linalool (69.2%) were detected as main compounds in the three thyme oil chemotypes. Treatments with essential oils might be harmful to the cells [ 35 – 37 ], therefore their effects on cell viability in different dilutions (200-fold, 500-fold and 1000-fold) at 6 h and 24 h long treatments were examined DMSO was used as a carrier in the stock solutions, therefore, the effect of DMSO on the cells was also determined. DMSO did not affect significantly the cell viability (Fig.…”

“…The alterations of the NF-κB signalling pathway could not explain completely the changes in the TNFα expression; therefore, the level of the P-C/EBPβ transcription factor, which has been described as a possible TNFα regulator in myelomonocytic cell lines [ 37 ] was also examined. All of the essential oil standards and among the chemotypes geraniol and thujanol could attenuate the effect of LPS pretreatment on P-C/EBPβ transcription factor (Fig.…”

Plant Extracts as Alternative Additives for Sperm Preservation

“…The extract of this plant was added to the extender for boar semen storage [76] at 17 • C. Among the four concentrations used, two of them (0.1% and 1%) showed cytotoxic effects immediately after their addition to the culture media. A concentration of 0.01% had deleterious effects on sperm parameters after 2 h of semen incubation.…”

“…The essential oil of this plant has been tested on boar sperm during 2 days of semen storage at 17 °C [ 76 ]. All the concentrations used (0.001-1%) were detrimental for sperm parameters.…”

Preliminary Assessment of the Mucosal Toxicity of Tea Tree (Melaleuca alternifolia) and Rosemary (Rosmarinus officinalis) Essential Oils on Novel Porcine Uterus Models

“…During the last decades, physical approaches were developed such as bacteria removal by colloid centrifugation [10] and microfiltration of seminal plasma [11], or the use of antimicrobial peptides [12,13]. At the same time, natural compounds, and in particular essential oils (EOs) were evaluated on semen of different species for their antioxidant and antimicrobial proprieties [14][15][16][17].…”