海星化学成分的生物活性及应用研究进展

海星中含有脂类、多糖、多肽及氨基酸、胶原蛋白、皂苷、甾醇、生物碱等多种营养成分和活性物质,具有广泛的生物活性和药理作用,在功能食品等领域具有巨大的开发潜力和广阔的市场前景。目前对海星的开发利用还十分局限,因此拓展开发思路,加强对海星的开发利用,具有重要的现实意义。通过综述国内外近10年来从海星中发现的一些新化学成分的生物活性和应用,为进一步开发利用海星提供理论依据。     

In Vitro Anticancer and Cancer-Preventive Activity of New Triterpene Glycosides from the Far Eastern Starfish Solaster pacificus

Sea stars or starfish (class Asteroidea) and holothurians or sea cucumbers (class Holothuroidea), belonging to the phylum Echinodermata (echinoderms), are characterized by different sets of glycosidic metabolites: the steroid type in starfish and the triterpene type in holothurians. However, herein we report the isolation of eight new triterpene glycosides, pacificusosides D–K (1–3, 5–9) along with the known cucumarioside D (4), from the alcoholic extract of the Far Eastern starfish Solaster pacificus. The isolated new compounds are closely related to the metabolites of sea cucumbers, and their structures of 1–3 and 5–9 were determined by extensive NMR and ESIMS techniques. Compounds 2, 5, and 8 have a new type of tetrasaccharide chain with a terminal non-methylated monosaccharide unit. Compounds 3, 6, and 9 contain another new type of tetrasaccharide chain, having 6-O-SO₃-Glc as one of the sugar units. The cytotoxic activity of 1–9 against non-cancerous mouse epidermal cells JB6 Cl41 and human melanoma cell lines SK-MEL-2, SK-MEL-28, and RPMI-7951 was determined by MTS assay. Compounds 1, 3, 4, 6, and 9 showed potent cytotoxicity against these cell lines, but the cancer selectivity (SI > 9) was observed only against the SK-MEL-2 cell line. Compounds 1, 3, 4, 6, and 9 at the non-toxic concentration of 0.1 μM significantly inhibited neoplastic cell transformation of JB6 Cl41 cells induced by chemical carcinogens (EGF, TPA) or ionizing radiation (X-rays and UVB). Moreover, compounds 1 and 4 at the non-toxic concentration of 0.1 µM possessed the highest inhibiting activity on colony formation among the investigated compounds and decreased the colonies number of SK-MEL-2 cells by 64% and 70%, respectively. Thus, triterpene glycosides 1 and 4 can be considered as prospective cancer-preventive and anticancer-compound leaders.     

Anti-Inflammatory Components of the Starfish Astropecten polyacanthus

Inflammation is important in biomedical research, because it plays a key role in inflammatory diseases including rheumatoid arthritis and other forms of arthritis, diabetes, heart disease, irritable bowel syndrome, Alzheimer’s disease, Parkinson’s disease, allergies, asthma, and even cancer. In the present study, we describe the inhibitory effect of crude extracts and steroids isolated from the starfish Astropecten polyacanthus on pro-inflammatory cytokine (Interleukin-12 (IL-12) p40, interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α)) production in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells (BMDCs). Among those tested, compounds 5 and 7 showed potent inhibitory effects on the production of all three pro-inflammatory cytokines with IC₅₀ values ranging from 1.82 ± 0.11 to 7.00 ± 0.16 μM. Potent inhibitory activities were also observed for compound 1 on the production of IL-12 p40 and IL-6 with values of 3.96 ± 0.12 and 4.07 ± 0.13 μM, respectively, and for compounds 3 and 4 on the production of IL-12 p40 with values of 6.55 ± 0.18 and 5.06 ± 0.16 μM, respectively. Moreover, compounds 2 (IC₅₀ = 34.86 ± 0.31 μM) and 6 (IC₅₀ = 79.05 ± 2.05 μM) exhibited moderate inhibitory effects on the production of IL-12 p40, whereas compounds 3 (IC₅₀ = 22.80 ± 0.21 μM) and 4 (IC₅₀ = 16.73 ± 0.25 μM) moderately inhibited the production of TNF-α and IL-6, respectively.     

Structure-Activity Relationship Study of the Neuritogenic Potential of the Glycan of Starfish Ganglioside LLG-3

LLG-3 is a ganglioside isolated from the starfish Linchia laevigata. To clarify the structure-activity relationship of the glycan of LLG-3 toward rat pheochromocytoma PC12 cells in the presence of nerve growth factor, a series of mono- to tetrasaccharide glycan derivatives were chemically synthesized and evaluated in vitro. The methyl group at C8 of the terminal sialic acid residue was crucial for neuritogenic activity, and the terminal trisaccharide moiety was the minimum active motif. Furthermore, the trisaccharide also stimulated neuritogenesis in human neuroblastoma SH-SY5Y cells via mitogen-activated protein kinase (MAPK) signaling. Phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 was rapidly induced by adding 1 or 10 nM of the trisaccharide. The ratio of phosphorylated ERK to ERK reached a maximum 5 min after stimulation, and then decreased gradually. However, the trisaccharide did not induce significant Akt phosphorylation. These effects were abolished by pretreatment with the MAPK inhibitor U0126, which inhibits enzymes MEK1 and MEK2. In addition, U0126 inhibited the phosphorylation of ERK 1/2 in response to the trisaccharide dose-dependently. Therefore, we concluded that the trisaccharide promotes neurite extension in SH-SY5Y cells via MAPK/ERK signaling, not Akt signaling.     

脱毒海星微波真空干燥工艺优化

为了提高脱毒海星干燥效率、品质及降低能耗,选择微波真空干燥方法进行试验研究。通过单因素试验研究了微波功率密度、脉冲时间及真空度对干燥特性、能耗及蛋白质保留率的影响。结果表明,在3~7 W/g、20~60 s和-0.070~-0.090 MPa范围内,较高的微波功率密度、较长的脉冲时间和较高的负压会缩短干燥时间、提高干燥平均速率、降低能耗;提高微波功率密度不利于蛋白质的保留,缩短脉冲时间和提高负压可提高脱毒海星的蛋白质保留率。利用响应面法探讨了微波功率密度、脉冲时间及真空度对脱毒海星微波真空干燥工艺的综合影响,建立了二次多项式回归模型,并对干燥工艺参数进行了优化。通过分析得出各因素影响的显著性依次为微波功率密度脉冲时间真空度,微波功率密度、脉冲时间对脱毒海星微波真空干燥有极显著性影响(P0.01),且微波功率密度与脉冲时间的交互作用比较明显(P0.05);脱毒海星的最佳微波真空干燥条件为微波功率密度为4 W/g,脉冲时间为60 s和真空度为-0.090 MPa,在此条件下脱毒海星微波真空干燥的综合评分最高,为0.751。研究结果可为脱毒海星干燥的工业化生产和有效利用提供参考。     

Violapyrones H and I,New Cytotoxic Compounds Isolated from Streptomyces sp. Associated with the Marine Starfish Acanthaster planci

Two new α-pyrone derivatives, violapyrones H (1) and I (2), along with known violapyrones B (3) and C (4) were isolated from the fermentation broth of a marine actinomycete Streptomyces sp. The strain was derived from a crown-of-thorns starfish, Acanthaster planci, collected from Chuuk, Federated States of Micronesia. The structures of violapyrones were elucidated by the analysis of 1D and 2D NMR and HR-ESIMS data. Violapyrones (1–4) exhibited cytotoxicity against 10 human cancer cell lines with GI₅₀ values of 1.10–26.12 μg/mL when tested using sulforhodamine B (SRB) assay. This is the first report on the cytotoxicity of violapyrones against cancer cell lines and the absolute configuration of violapyrone C.     

几种海洋药用动物中重金属元素的含量分析

对我国几种传统海洋药用动物中重金属元素的含量进行了测定,并对同产地的陆生药用动物蛤蚧进行比较研究,其中Hg和As利用原子荧光光度计测定,Pb、Cd、Cu、Fe、Mn、Zn利用原子吸收光度计测定,样品采用微波消解仪消解。结果表明:海钱、海蛇、海马、海星的镉含量较高,海燕、海马、海星的铅含量较高,除个别样品微量元素未检出外,样品中Fe、Mn、Zn的含量相对较高。最后对金属元素含量较高的原因及对所含微量元素的食用安全性和营养学评价进行了探讨。     

Four New Sulfated Polar Steroids from the Far Eastern Starfish Leptasterias ochotensis: Structures and Activities

Three new sulfated steroid monoglycosides, leptaochotensosides A–C (1–3), and a new sulfated polyhydroxylated steroid (4) were isolated from the alcoholic extract of the Far Eastern starfish Leptasterias ochotensis. The structures of compounds 1–4 were established by extensive nuclear magnetic resonance (NMR) and electrospray ionization mass spectrometry (ESIMS) analyses and chemical transformations. Although the isolated compounds did not show any apparent cytotoxicity against melanoma RPMI-7951 and breast cancer T-47D cell lines, leptaochotensoside A (1) demonstrated inhibition of T-47D cell colony formation in a soft agar clonogenic assay at nontoxic doses. In addition, this compound decreased the epidermal growth factor (EGF)-induced colony formation of mouse epidermal JB6 Cl41 cells. The cancer preventive action of 1 is realized through regulation of mitogen-activated protein kinase (MAPK) signaling pathway.     

Structural characterization of plancitoxin I, a deoxyribonuclease II-like lethal factor from the crown-of-thorns starfish Acanthaster planci , by expression in Chinese hamster ovary cells

Plancitoxin I, the major lethal factor from the spines of crown-of-thorns starfish Acanthaster planci, is a 37 kDa protein composed of two different subunits, and it has potent hepatotoxicity. It is homologous with mammalian deoxyribonuclease II (DNase II) and exhibits DNase activity responsible for the hepatotoxicity. To obtain information on the structure–activity relationship of plancitoxin I, various mutants were expressed in Chinese hamster ovary cells and examined for DNase activity. The results with deletion mutants revealed the requirement of the signal peptide for the expression of intact plancitoxin I and the inability of each subunit to hydrolyze DNA. Mutation at the N-glycosylation site (Asn-274) did not reduce DNase activity, supporting the absence of carbohydrate moieties in the molecule. The mutant H303A exhibited no DNase activity, suggesting the importance of His-303 for the enzymatic activity. No DNase activity was detected in C29A, C169A, C318A and C337A, indicating that four Cys residues are critical to the enzymatic activity. However, DNase activity was completely maintained in C263A and somewhat reduced in C277A and C357A. Based on the results with the Cys-specific mutants, plancitoxin I was assumed to contain three disulfide bridges (29–169, 277–357 and 318–337) and one free Cys-263.