Effects of aqueous crude extract of Echeveria gibbiflora on mouse sperm function

The present study evaluates the possible antifertility effect of aqueous crude extract (OBACE) of Echeveria gibbiflora, a plant that belongs to the crassulaceae family, used in traditional Mexican medicine as a vaginal post coital rinse to prevent pregnancy and shown to have an immobilization/agglutination effect on sperm of different mammal species. We evaluated the effect of OBACE on functional parameters of mouse sperm, such as viability, capacitation, and acrosome reaction. In addition, due to the high concentrations of calcium bis-(hydrogen-1-malate) hexahydrate [Ca (C₄H₅O₅)₂?6H₂O] present in this plant extract, we evaluated its effect on Ca²⁺ influx in mouse sperm under capacitating conditions. Moreover, we determined the acute toxicity of OBACE and its in vivo effect in mouse sperm motility administering a single daily dose of 50 and 100 mg/kg during seven days, intraperitoneally. The sperm viability was not affected by the presence of different concentrations of OBACE, however, the capacitation and acrosome reaction suffered a significant decrease in a concentration-dependent manner, coinciding with the reduction of Ca²⁺ influx. Furthermore, OBACE displayed an LD₅₀ of 3,784.42 mg/kg and can be classified as a low toxic substance. Also, in vivo OBACE showed an inhibition of total and progressive motility on mouse sperm alongside a significant decrease of motility kinematic parameters and IVF rates. The results confirm the antifertility effect of this plant used in Mexican folk medicine. Further study on OBACE as a possible contraceptive treatment is warranted because of its activity and low in vivo toxicity.

Abbreviations: ALH: lateral amplitude; AP: acid phosphatase; BCF: beat frequency; BSA: bovine serum albumine; CTC: chlortetracycline; FDA: fluorescein diacetate; Fura-2 AM: fura-2-acetoxymethyl ester; HIV: human immunodeficiency virus; IVF: in vitro fertilization; OBACE: aqueous crude extract of Echeveria gibbiflora; PI: propidum iodide; SN: supernatant; VAP: average path velocity; VCL: track speed; VSL: straight line velocity