Department of Reproductive Biology, Indian Institute of Chemical Biology (Council of Scientific and Industrial Research), Kolkata, India.
Reprod Sci. 2010 May;17(5):454-64. doi: 10.1177/1933719110361378. Epub 2010 Mar 10.
The seed extracts of Madhuca latifolia were reported to have spermicidal activity. The current investigation identified the spermicidal component of the extracts and evaluated its spermicidal potential in vitro. As characterized by infrared, mass, and nuclear magnetic resonance (NMR) spectral analyses, Mi-saponin A (MSA) was found to be the most potent component among a mixture of saponins. The mean effective concentrations of MSA that induced irreversible immobilization were 320 microg/mL for rat and 500 microg/mL for human sperm, as against the respective concentrations of 350 and 550 microg/mL of nonoxynol 9 (N-9). The mode of spermicidal action was evaluated by a battery of tests including (a) double fluoroprobe staining for sperm viability, (b) hypoosmotic swelling test and, assays for 5' nucleotidase and acrosin for physiological integrity of sperm plasma membrane, (c) scanning and transmission electron microscopy for sperm membrane ultrastructure, and (d) plasma membrane lipid peroxidation (LPO). The observations, taken together, were interpreted to mean that the spermicidal effect of MSA involved increased membrane LPO leading to structural and functional disintegration of sperm plasma membrane and acrosomal vesicle. A comparative in vitro cytotoxicity study in human vaginal keratocyte (Vk2/E6E7) and endocervical (End/E6E7) cell lines demonstrated that the 50% cell cytotoxicity (CC(50)) values, and consequently the safety indices, for MSA were >or= 8-fold higher as compared to those of N-9. In conclusion, MSA is a potent spermicidal molecule that may be explored further for its suitability as an effective component of vaginal contraceptive.
厚叶破布木的种子提取物被报道具有杀精活性。目前的研究鉴定了提取物中的杀精成分，并评估了其在体外的杀精潜力。红外、质谱和核磁共振（NMR）谱分析表明，米皂素 A（MSA）是皂素混合物中最有效的成分。MSA 诱导精子不可逆失活的平均有效浓度，大鼠为 320μg/mL，人精子为 500μg/mL，而非诺孕醇 9（N-9）的相应浓度分别为 350μg/mL 和 550μg/mL。通过一系列试验评估杀精作用模式，包括（a）双荧光探针染色检测精子活力，（b）低渗肿胀试验和 5'核苷酸酶和顶体酶测定检测精子质膜的生理完整性，（c）扫描和透射电子显微镜检查精子质膜超微结构，以及（d）质膜脂质过氧化（LPO）。综合观察结果表明，MSA 的杀精作用涉及增加质膜 LPO，导致精子质膜和顶体囊泡的结构和功能解体。在人阴道角质细胞（Vk2/E6E7）和宫颈内细胞（End/E6E7）细胞系中的体外细胞毒性比较研究表明，MSA 的 50%细胞毒性（CC（50））值和相应的安全指数比 N-9 高 8 倍以上。总之，MSA 是一种有效的杀精分子，可能进一步探索其作为阴道避孕药的有效性成分。
