An alternative medicine study of herbal effects on the penetration of zona-free hamster oocytes and the integrity of sperm deoxyribonucleic acid

Objective: To analyze the effects of certain herbs on sperm DNA and on the fertilization process. Design: Prospective comparative study. Setting: Clinical and academic research environment. Patient(s): Donor sperm specimens. Intervention(s): Zona-free hamster oocytes were incubated for 1 hour in saw palmetto ( Serenoa repens ), echinacea purpura, ginkgo biloba, St. John's wort ( Hypericum perforatum ), or control medium before sperm-oocyte interaction. The DNA of herb-treated sperm was analyzed with denaturing gradient gel electrophoresis. Main Outcome Measure(s): Oocyte penetration and integrity of the sperm BRCA1 exon 11 gene. Result(s): Pretreatment of oocytes with 0.6 mg/mL of St. John's wort resulted in zero penetration. A lower concentration (0.06 mg/mL) had no effect. High concentrations of echinacea and ginkgo also resulted in reduced oocyte penetration. Exposure of sperm to echinacea purpura and St. John's wort resulted in DNA denaturation. In contrast, saw palmetto and ginkgo had no effect. Sperm exposed to 0.6 mg/mL of St. John's wort showed mutation of the BRCA1 exon 11 gene. Conclusion(s): High concentrations of St. John's wort, echinacea, and ginkgo had adverse effects on oocytes. Saw palmetto had no effect. The data suggested that St. John's wort, ginkgo, and echinacea at high concentrations damage reproductive cells. St. John's wort was mutagenic to sperm cells.