羽扇豆醇通过抑制RhoA-ROCK1信号通路抑制结肠癌细胞增殖

该文探讨了羽扇豆醇(Lupeol)对人结肠癌HCT116和SW620细胞增殖的影响及相关作用机制。使用不同浓度的Lupeol处理HCT116和SW620细胞后,用MTT法检测细胞活性,CCK8法检测细胞增殖能力,平板克隆实验检测细胞克隆形成能力,流式细胞术检测细胞周期和细胞凋亡,(quantitative real-time PCR,qPCR)和Western blot检测相应mRNA和蛋白表达水平,免疫荧光检测β-Catenin蛋白细胞内分布情况。通过构建shRNA敲低两种结肠癌细胞中RhoA,进一步研究Lupeol影响细胞增殖的分子机制。结果显示,Lupeol处理后,HCT116和SW620细胞增殖能力明显下降,克隆形成能力受到抑制,细胞周期阻滞于G0/G1期,细胞内RhoA、ROCK1、β-Catenin、Cyclin D1 mRNA和蛋白表达水平均显著下降,β-Catenin蛋白胞质和胞膜上分布减少。敲低RhoA后抑制了细胞增殖,同时使得RhoA-ROCK1-β-Catenin信号通路蛋白受到抑制,β-Catenin蛋白胞质和胞膜上分布减少。综上所述,Lupeol可通过抑制RhoA-ROCK1信号通路,抑制β-Catenin蛋白表达,进而抑制HCT116和SW620细胞增殖,Lupeol有望成为临床结肠癌治疗的新药物。     

Molecular cloning and functional expression of a multifunctional triterpene synthase cDNA from a mangrove species Kandelia candel (L.) Druce

Homology based PCRs with degenerate primers designed from the conserved sequences among the known oxidosqualene cylases (OSCs) have resulted in cloning of a triterpene synthase (KcMS) from the young roots of Kandelia candel (L.) Druce (Rhizophoraceae). KcMS consists of a 2286 bp open reading frame, which codes for 761 amino acids. The deduced amino acid sequence showed 79% homology to a lupeol synthase from Ricinus communis suggesting it to be a lupeol synthase of K. candel. KcMS was expressed in a lanosterol synthase deficient yeast with the expression vector pYES2 under the control of GAL1 promoter. GC-MS analysis showed that the transformant accumulated a mixture of lupeol, beta-amyrin and alpha-amyrin in a 2:1:1 ratio, indicating that KcMS encodes a multifunctional triterpene synthase, although it showed high sequence homology to a R. communis lupeol synthase. This is the first OSC cloning from mangrove tree species.     

A case of mistaken identity: Lupeol-3-(3′R)-hydroxy-stearate can be mistakenly identified as lupeol acetate when only analyzed by GC–MS

Lupeol-3-(3′R-hydroxy)-stearate, also known as procrim b (1), was isolated from the methanolic stem extract of Pentalinon andrieuxii and initially mistaken as lupeol acetate when analyzed by GC–MS only. The correct structure of 1 was established following a careful analysis of its NMR and MS data.     

Synthesis of new heterocyclic lupeol derivatives as nitric oxide and pro-inflammatory cytokine inhibitors

A series of heterocyclic derivatives including indoles, pyrazines along with oximes and esters were synthesized from lupeol and evaluated for anti-inflammatory activity through inhibition of lipopolysaccharide (LPS) induced nitric oxide (NO) production in RAW 264.7 and J774A.1 cells. All the synthesized molecules of lupeol were found to be more active in inhibiting NO production with an IC₅₀ of 18.4–48.7 μM in both the cell lines when compared to the specific nitric oxide synthase (NOS) inhibitor, L-NAME (IC₅₀ = 69.21 and 73.18 μM on RAW 264.7 and J774A.1 cells, respectively). The halogen substitution at phenyl ring of indole moiety leads to potent inhibition of NO production with half maximal concentration ranging from 18.4 to 41.7 μM. Furthermore, alkyl (11, 12) and p-bromo/iodo (15, 16) substituted compounds at a concentration of 20 μg/mL exhibited mild inhibition (29–42%) of LPS-induced tumor necrosis factor alpha (TNF-α) and weak inhibition (10–22%) towards interleukin 1-beta (IL-1β) production in both the cell lines. All the derivatives were found to be non-cytotoxic when tested at their IC₅₀ (μM). These findings suggest that the derivatives of lupeol could be a lead to potent inhibitors of NO.     

Prevention of prostate cancer through custom tailoring of chemopreventive regimen

One practical way to control cancer is through chemoprevention, which refers to the administration of synthetic or naturally occurring agents to block, reverse or delay the process of carcinogenesis. For a variety of reasons, the most important of which is human acceptance, for chemopreventive intervention naturally occurring diet-based agents are preferred over synthetic agents. For a long time, the prevailing mantra of cancer chemoprevention has been: "Find effective agents with acceptable or no toxicity and use them in preventing cancer in relatively healthy people or individuals at high risk for developing cancer". In pursuing this goal many naturally occurring phytochemicals capable of affording protection against carcinogenesis in preclinical settings in experimental animals have been described. However, clinical trials of single agents have yielded disappointing results. Since carcinogenesis is a multistage phenomenon in which many normal cellular pathways become aberrant, it is unlikely that one agent could prove effective in preventing cancer. This review underscores the need to build an armamentarium of naturally occurring chemopreventive substances that could prevent or slow down the development and progression of prostate cancer. Thus, the new effective approach for cancer prevention "building a customized mechanism-based chemoprevention cocktail of naturally occurring substances" is advocated.     

Triterpenoids from Parthenium argentatum x P. tomentosa

Four tetracyclic triterpenoids and lupeol were isolated from the hybrid Parthenium argentatum x P. tomentosa. The new triterpenoids were identified as 16, 24-epoxy-3α-hydroxylanost-8-ene (argentatin E); 16, 24-epoxy-25-hydroxycycloart-1, 11, 22-trien-3-one (argentatin F); 16,24-dihydroxycycloart-20, 25-dien-3-one (argentatin G) and 16, 24-dihydroxycycloart-25-en-3-one (argentatin H). The chemical identities of these compounds were confirmed by the different spectrometric measurements.     

LC-MS导向分离山壳骨中主成分及其生物活性研究

为了解山壳骨(Pseuderanthemum latifolium)的化学成分和生物活性,运用LC-MS联用技术分离得到羽扇豆醇(1)和豆甾醇(2)。体外活性评价结果表明,化合物1和2均具有中等的抗MRSA活性,但不具有神经保护作用。这是首次对山壳骨进行化学成分和生物活性研究,为综合开发与利用山壳骨提供科学依据。     

旋覆花提取物对朱砂叶螨的生物活性及酶活性的影响

本文研究了旋覆花石油醚提取物对朱砂叶螨的毒力作用及其对相关酶活性的影响。结果表明：旋覆花石油醚提取物的杀螨活性较高,浓度为2mg?mL-1 时,校正死亡率达到92.05％。通过对旋覆花石油醚提取物进一步萃取、柱层析分离、薄层层析,发现最终得到的38个流分中,杀螨效果较好的是流分7,其校正死亡率为85.53%。流分7经GC/MS鉴定为羽扇豆醇,其校正死亡率达到66.46%。进一步测定羽扇豆醇对朱砂叶螨谷胱甘肽-S-转移酶、Ca2 -ATPase、过氧化物歧化酶的活性以及总蛋白含量的影响,结果表明经羽扇豆醇处理后,螨体内过氧化物歧化酶被激活,而谷胱甘肽-S-转移酶和Ca2 -ATPase均受到不同程度的抑制,蛋白总量在这个过程中没有明显的变化。上述结果表明旋覆花提取物羽扇豆醇可以有效地杀死朱砂叶螨,这为旋覆花作为新型植物源农药提供一定的理论依据。