光对马卡愈伤组织生长、丛生芽诱导和存活的影响

马卡属于十字花科独行菜属,具有极高的营养价值和药用价值。在快繁过程中,光对马卡愈伤组织生长,丛生芽的诱导和存活有显著的影响。绿光和蓝光既不利于愈伤组织的生长也不利于丛生芽的诱导和存活。白光、红光和黄光能明显促进愈伤组织的生长,在这些光照条件下丛生芽的诱导率为60%～80%,丛生芽存活率为29%～36%。适当延长光照时间可提高丛生芽的存活率,合适的光照时间为16h/d。但是过强的光照可使丛生芽的存活率降低,合适的光照强度为24～41μmol/m2.s。     

The in vitro biological activity of Lepidium meyenii extracts

The biological activity of methanolic and aqueous extracts from dehydrated hypocotyls of Lepidium meyenii (Brassicaceae, vernacular name “maca”), was studied on rat hepatocytes and human breast cancer MCF-7 cells. The extracts did not exhibit cytotoxicity in hepatocyte primary cultures up to 10 mg/ml as measured by the MTT viability test, and lactate dehydrogenase (LDH) and aspartate aminotransferase (AST) leakage. Moreover, after 72 h, extracts inhibited LDH and AST leakage from the hepatocytes. When hepatocytes were intoxicated by t-butyl hydroperoxide, neither extract prevented oxidative damage. Both extracts showed weak antioxidant activity in the DPPH radical scavenging test with IC₅₀ values of 3.46 ± 0.16 and 0.71 ± 0.10 mg/ml, for aqueous and methanolic extracts, respectively. Thus, the observed effect on spontaneous enzyme leakage is probably mediated through mechanisms other than antioxidant activity. Both methanolic and aqueous extracts have shown estrogenic activity comparable with that of silymarin in MCF-7 cell line. Maca estrogenicity was exhibited in the range from 100 to 200 μg of extract per ml. The findings in the present study show that maca does not display in vitro hepatotoxicity. In contrast, a slight cytoprotective effect, probably not mediated by antioxidant capacity, was noted. Maca extracts exhibited estrogenic activity comparably to the effect of silymarin in MCF-7 cells.     

玛咖提取物对运动耐力和脊神经元线粒体超微结构的影响

目的：探索玛咖提取物对运动耐力和脊神经元线粒体超微结构的影响。方法：50只Wistar大鼠随机分为5组。对照组：不进行游泳,灌胃等量蒸馏水;单纯游泳组：游泳,灌胃等量蒸馏水,玛咖提取物组（设4.0,5.3,8.0 g/kg 3个剂量组）：游泳,给予相应剂量的玛咖提取物。游泳大鼠在游泳池内循环水流自由游泳,连续游泳并给药15 d,第16天游泳耐力测试后无痛处死大鼠,用投射电子显微镜观察脊髓神经元线粒体超微结构,放免法测定肌肉肌糖元、检测肌肉中丙二醛（MDA）、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）和游离钙水平。结果：与单纯游泳组比,沉下前游泳时间和游泳总时间分别延长了（%）19.83、60.28、77.55和55.34、73.91、94.47,差异均有统计学意义（P均<0.01）;沉下次数分别减少了（%）34.35、51.18、57.96,差异有统计学意义（P<0.01）;MDA和游离钙含量分别降低了（%）20.10、31.49、38.72,差异有统计学意义（P<0.01）和6.42、17.58、26.35;SOD、GSH-Px和肌糖原含量分别升高了（%）5.12、22.74、52.53、44.22、77.79、98.45,差异有统计学意义（P<0.01）和35.08、47.83、81.88,差异有统计学意义（P<0.01）;脊神经元线粒体的体密度（VD）、面密度（SD）和数密度（ND）分别减小了（%）7.79、18.18、31.17,16.95、27.34、43.31和13.51、23.19、43.15。结论：玛咖提取物具有保护脊髓神经元线粒体结构、抗氧化、增加肌糖原和提高运动能力等作用。