Topical Capsaicin in Poly(lactic-co-glycolic)acid (PLGA) Nanoparticles Decreases Acute Itch and Heat Pain

Background: Capsaicin, the hot pepper agent, produces burning followed by desensitization. To treat localized itch or pain with minimal burning, low capsaicin concentrations can be repeatedly applied. We hypothesized that alternatively controlled release of capsaicin from poly(lactic-co-glycolic acid) (PLGA) nanoparticles desensitizes superficially terminating nociceptors, reducing burning. Methods: Capsaicin-loaded PLGA nanoparticles were prepared (single-emulsion solvent evaporation) and characterized (size, morphology, capsaicin loading, encapsulation efficiency, in vitro release profile). Capsaicin-PLGA nanoparticles were applied to murine skin and evaluated in healthy human participants (n = 21) for 4 days under blinded conditions, and itch and nociceptive sensations evoked by mechanical, heat stimuli and pruritogens cowhage, β-alanine, BAM8-22 and histamine were evaluated. Results: Nanoparticles (loading: 58 µg capsaicin/mg) released in vitro 23% capsaicin within the first hour and had complete release at 72 h. In mice, 24 h post-application Capsaicin-PLGA nanoparticles penetrated the dermis and led to decreased nociceptive behavioral responses to heat and mechanical stimulation (desensitization). Application in humans produced a weak to moderate burning, dissipating after 3 h. A loss of heat pain up to 2 weeks was observed. After capsaicin nanoparticles, itch and nociceptive sensations were reduced in response to pruritogens cowhage, β-alanine or BAM8-22, but were normal to histamine. Conclusions: Capsaicin nanoparticles could be useful in reducing pain and itch associated with pruritic diseases that are histamine-independent.     

含辣椒碱的抗菌高吸水树脂的合成

以过硫酸铵、亚硫酸氢钠作引发剂,N,N’-亚甲基双丙烯酰胺作交联剂,将木薯淀粉与丙烯酸、辣椒碱在水溶液中接枝共聚,合成了具有抗菌性的高吸水性树脂。考察了添加辣椒碱形式、反应温度、反应时间、丙烯酸中和度、引发剂和交联剂用量对产物吸水性能的影响,结果表明,添加辣椒碱提取母液,在70℃下反应2．5h,丙烯酸中和度85％,引发剂和交联剂用量分别为0．6％和0．04％时,合成的吸水树脂有较高的吸水倍率。     

油温对辣椒油品质的影响

利用色差仪、气相色谱-质谱联用和紫外可见光分光光度计等仪器对不同油温浸提辣椒油的色泽、挥发性成分及辣椒素进行分析.结果表明:油温为140℃时辣椒油色泽鲜红,随着油温上升,辣椒油的色泽逐渐变亮,红色程度降低;当油温超过180℃后,辣椒油色泽明显变暗变黑.辣椒油中挥发性成分共有58种,分为13类,分别为醛类化合物、醇类化合...     

云南丘北辣椒中辣椒素酶法提取条件的优化

利用响应面分析法优化了酶法提取辣椒素的条件,在统计分析后得出了果汁专用复合酶作用于云南丘北辣椒提取辣椒素的酶解方程,精确地预测了辣椒素的提取率。     

NGF Enhances CGRP Release Evoked by Capsaicin from Rat Trigeminal Neurons: Differential Inhibition by SNAP-25-Cleaving Proteases

Nerve growth factor (NGF) is known to intensify pain in various ways, so perturbing pertinent effects without negating its essential influences on neuronal functions could help the search for much-needed analgesics. Towards this goal, cultured neurons from neonatal rat trigeminal ganglia—a locus for craniofacial sensory nerves—were used to examine how NGF affects the Ca²⁺-dependent release of a pain mediator, calcitonin gene-related peptide (CGRP), that is triggered by activating a key signal transducer, transient receptor potential vanilloid 1 (TRPV1) with capsaicin (CAP). Measurements utilised neurons fed with or deprived of NGF for 2 days. Acute re-introduction of NGF induced Ca²⁺-dependent CGRP exocytosis that was inhibited by botulinum neurotoxin type A (BoNT/A) or a chimera of/E and/A (/EA), which truncated SNAP-25 (synaptosomal-associated protein with Mr = 25 k) at distinct sites. NGF additionally caused a Ca²⁺-independent enhancement of the neuropeptide release evoked by low concentrations (<100 nM) of CAP, but only marginally increased the peak response to ≥100 nM. Notably, BoNT/A inhibited CGRP exocytosis evoked by low but not high CAP concentrations, whereas/EA effectively reduced responses up to 1 µM CAP and inhibited to a greater extent its enhancement by NGF. In addition to establishing that sensitisation of sensory neurons to CAP by NGF is dependent on SNARE-mediated membrane fusion, insights were gleaned into the differential ability of two regions in the C-terminus of SNAP-25 (181–197 and 198–206) to support CAP-evoked Ca²⁺-dependent exocytosis at different intensities of stimulation.     

辣椒碱合成方法的改进

以6-溴己酸为起始原料,经Wittig反应、胺化还原反应、N-酰化反应,制备了N-[（4-羟基-3-甲氧基苯基）-甲基]-8-甲基-6-壬烯酰胺,经EI-MS、1H NMR等测试技术分析确定了目标化合物的分子结构。     

辣椒碱的合成研究进展

辣椒碱广泛应用于医药、农药等领域。本文综述了辣椒碱的合成研究进展,指出了辣椒碱合成研究中存在的主要问题一一如何立体选择性地合成出反式双键,以及烯烃的顺式结构转变为反式结构的异构化反应。最后展望了辣椒碱合成研究的发展方向。     

辣椒碱的应用研究进展

介绍了国内外有关辣椒碱在医药、生物农药、涂料、食品添加剂及军事领域的应用研究进展,并预期辣椒碱的新用途会随着科学技术的进步得到不断开发,其应用前景相当广阔。     

辣椒碱在不同溶剂中溶解度的测定与关联

应用平衡法,以辣椒碱晶体(含辣椒碱50.4%,二氢辣椒碱37.1%,降二氢辣椒碱7.9%)为原料,在262~333 K温度下测定了辣椒碱在甲醇、乙醇、正丁醇等9种溶剂中的溶解度曲线,分别采用理想溶液模型、Apelblat模型和多项式经验方程对实验数据进行关联. 结果表明,9种溶剂中,辣椒碱的溶解度均随温度升高而增大,辣椒碱在正丁醇中的溶解度最大,在水中的溶解度最小. 计算表明,乙醚适合作为辣椒碱的冷却结晶溶剂,产率为51.23%. 模型关联结果为理想溶液模型的误差较大,多项式经验方程的误差最小.