荔枝果皮总花色苷及降解指数的测定

本文研究了荔枝果皮总花色苷及其降解指数的含量测定。结果表明,当荔枝果皮发生褐变时,1％盐酸甲醇提取液花色苷及降解指数含量显著偏高。荔枝果皮总花色苷及花色苷降解指数可以很好地反映出提取液中花色苷的降解情况。     

Eudesmane sesquiterpene glucosides from lychee seed and their cytotoxic activity

Two new sesquiterpene glucosides, litchiosides A (1) and B (2), were obtained along with pumilaside A (3) and funingensin A (4) from lychee (Litchi chinensis Sonn.) seed. Their structures were elucidated on the basis of spectroscopic and chemical evidence. The in vitro antitumour activity of compounds 1–4 against A549, LAC, Hela, and Hep-G2 cell lines was determined using the MTT colourimetric assay. Pumilaside A (3) exhibited significant activity against all the tested cell lines with IC₅₀ values of 0.012–6.29 μM, and funingensin A (4) showed moderate activity against Hep-G2 cells (IC₅₀ = 39.27 μM), while litchiosides A (1) and B (2) were found to be inactive.     

广州亚运与城市更新的反思——以广州市荔湾区荔枝湾整治工程为例

广州市荔湾区荔枝湾整治工程采取建筑抽疏、拆违建绿、恢复河涌、调水补水、文塔广场恢复整治、建筑立面整饰与景观塑造等措施,规划打造"诗意广州",重现"一弯江水绿,两岸荔枝红"的岭南水乡风貌。在项目执行过程中,因亚运会对市场的激活有限、城市更新中行为与制度间存在矛盾冲突等,导致规划目的与实施产生脱节现象,因此要在服务公益、服务亚运的目标下进行制度创新,有效实现城市更新的多元目标。     

Antioxidant properties of various solvent extracts from lychee (Litchi chinenesis Sonn.) flowers

The antioxidant capacities of the acetone, methanol and water extracts of hot-air dried lychee (Litchi chinenesis Sonn.) flowers were estimated with Trolox equivalent antioxidant capacity (TEAC) assay, reducing power and 2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH) radical-scavenging assay. The contents of antioxidant components in these extracts were also determined. Results showed that the highest and lowest contents of these components including phenols, flavonoids and condensed tannins were found in acetone and water extracts, respectively. The antioxidant activities of the lychee flower extracts for all assays were in the order: acetone extract > methanol extract > water extract. The contents of antioxidant components in these extracts were correlated with antioxidant activities.     

真空冷冻干燥荔枝果肉工艺研究

对荔枝果肉真空冷冻干燥工艺作了初步研究。通过对荔枝果肉进行护色、速冻处理，探讨其最佳工艺参数。试验结果表明：用柠檬酸和抗坏血酸混合液(pH值＝3．0)处理的护色效果最好；速冻时间在2．5h为最好，经过护色、速冻处理后再真空冷冻干燥的荔枝果肉干基本保持原有的色、香、味、形状和营养成分，易于复水。     

γ-聚谷氨酸对荔枝常温货架保鲜效果研究

为提高荔枝贮藏保鲜质量、延长货架期,研究了生物高分子γ-聚谷氨酸在保鲜领域的应用情况。本论文通过对新鲜荔枝进行γ-聚谷氨酸涂膜处理保鲜实验,研究常温贮藏过程中荔枝的生理变化。结果表明:6g/Lγ-聚谷氨酸涂膜处理能够显著降低果实的二氧化碳释放率和乙烯释放率,防止水分散失,推迟花色素苷的降解,降低多酚氧化酶、过氧化物酶的活性变化,常温下能够有效延长荔枝保鲜期4d左右。     

荔枝核皂苷对老年痴呆大鼠的干预作用研究

目的: 建立老年痴呆(Alzheimer's disease, AD)大鼠模型,探讨荔枝核皂苷对AD大鼠的治疗作用及其机制。方法: 50只SD大鼠分为:对照组、模型对照组和低、中、高剂量荔枝核皂苷治疗组,共5组,每组10只;Morris水迷宫实验检测各组大鼠的逃避潜伏时间和平台跨越次数;Western blot实验检测各组脑组织β淀粉样蛋白(β-amyloid protein,Aβ)的表达变化;流式细胞仪检测各组脑组织活性氧(ROS)表达的改变。结果: AD大鼠模型组与对照组比较,逃避潜伏时间出现显著性地延长(P<0.01),平台跨越次数显著性地减少(P<0.01)。荔枝核皂苷治疗后AD大鼠的逃避潜伏时间和平台跨越次数得到显著性地改善(P<0.05)。AD大鼠脑组织Aβ的表达水平显著高于正常对照组,高、中、低剂量荔枝核皂苷治疗组可以剂量依赖性地降低模型鼠脑组织中Aβ的表达水平。对照组、模型对照组、低剂量荔枝核皂苷治疗组、中剂量荔枝核皂苷治疗组、高剂量荔枝核皂苷治疗组ROS表达水平的相对值分别为 6.12±0.61、9.54±1.42、8.33±1.26、7.68±1.14、7.23±0.73,模型组显著高于对照组(P<0.01),荔枝核皂苷治疗可以显著降低模型组脑组织中ROS的表达水平(P<0.05)。结论: 荔枝核皂苷具有抗AD大鼠痴呆的活性,减少AD大鼠脑组织Aβ和ROS的生成是其主要的作用机制。     

Lychee (Litchi chinensis Sonn.) seed water extract as potential antioxidant and anti-obese natural additive in meat products

The antioxidative properties of lychee seed water extract (LSWE) in raw meat paste during a storage period of 0–15 days at 4 °C were evaluated. The cytotoxic effects and the anti-obese effects of LSWE were evaluated using an in vitro 3T3-L1 preadipocyte cell model. The sensory properties of the cooked meat paste supplemented with different amount of LSWE were also evaluated. Results showed that LSWE was non-toxic and effective in inhibiting preadipocyte differentiation. These effects were attributable to down-regulation of several adipogenesis-specific genes, i.e., PPAR γ, C/EBP α, C/EBP β, C/EBP δ, and KLF9. Supplementation with LSWE was also effective in retarding lipid oxidation of meat paste. Sensory evaluation indicated that LSWE did not adversely affect the sensory properties of the meat paste. On the contrary, LSWE significantly improved the sensory properties of the meat paste during the late stage of the storage period. Based on the results, LSWE was determined to be effective in inhibiting adipogenesis and retarding lipid oxidation, which can improve the safety and quality of meat products.