苦瓜多糖的树脂纯化及其对MCF-7增殖抑制作用

采用LSA-21作为纯化苦瓜多糖的大孔吸附树脂,以多糖纯度为指标,考察多糖上样浓度和体积、乙醇溶液洗脱剂浓度及体积对苦瓜多糖纯化效果的影响。结果表明:在室温条件下多糖上样的质量浓度为2.0mg/mL,多糖上样体积为2.96BV,洗脱剂浓度为52.34%,洗脱剂体积为2.22BV时,多糖含量从26.01%提高到66.5%,其中蛋白质含量分别为4.12%和5.60%,水分含量分别为19.2%和18.9%。抑制MCF-7增殖试验结果表明:多糖纯度为26.01%,多糖作用剂量为5.40μg时,对MCF-7的抑制率达到最大值,为49.5%;多糖纯度为66.5%,多糖作用剂量仅为0.382μg,对MCF-7的抑制率可达到最大值,为46.5%,纯化后的苦瓜多糖用量比纯化前的用量显著降低。     

Screening of antioxidant activity and antioxidant compounds of some edible plants of Thailand

A large number of plants, which have been used as food and herbs in Thailand, were investigated for their antioxidant activity by using a β-carotene bleaching method. The contents of plant chemicals, such as vitamin C, vitamin E, carotenoids, tannin, and total phenolics, were also determined. The results showed that the highest antioxidant activity was found in the plant Gymnema inodorum, followed by Piper sarmentosum and Mentha arvensis, respectively. G. inodorum also contained the highest amount of vitamin E, and M. arvensis contained the highest amount of total xanthophylls. Correlations between the chemical content of each plant and the antioxidant index were observed. The results suggest that chemicals such as vitamin C, vitamin E, carotenoids, and phenolic compounds are the contributors to the antioxidant activity in the plants.     

4种野生菌多酚的体外抗氧化活性

测定了黄皮疣柄牛肝菌、马勃菌、黑牛肝菌及鸡枞等4种野生菌多酚含量并研究了粗多酚的抗氧化活性。结果表明:4种野生菌的60%(体积分数)乙醇提取物对DPPH自由基、ABTS自由基和羟自由基都具有很好的清除能力,且该清除能力与多酚浓度呈现良好的剂量相关性。4种野生菌都具有较好的铁离子还原能力,EC_(50)值介于0.02~0.04。总体来说,在4种野生菌中,黄皮疣柄牛肝菌多酚抗氧化活性最好,黑牛肝菌相对其他野生菌抗氧化活性较差。     

Antimicrobial activity and bioactive compounds of Portuguese wild edible mushrooms methanolic extracts

The antimicrobial properties of phenolic extracts of Portuguese wild edible mushroom species (Lactarius deliciosus, Sarcodon imbricatus and Tricholoma portentosum) against pathogens were investigated. The minimal inhibitory concentrations (MICs) were evaluated for the entire mushroom, the cap and the stipe, separately; the portion of the mushroom used proved to be influenced in the results obtained, which are directly correlated with the content of total phenols and flavonoids in the extracts. The growth of Gram-positive bacteria (Bacillus cereus, B. subtilis,) was well inhibited by these mushrooms, while Escherichia coli (Gram-negative bacteria) was resistant. The study on the antifungal effect of these mushrooms revealed that Candida albicans and Cryptococcus neoformans were differently inhibited for the mushrooms used.     

Lipids classes, fatty acids and carotenes of the leaves of six edible wild plants

 α-Linolenic acid and unusual fatty acids of the ω3 and ω6 series play an important role in the modulation of human metabolism. The presence of these acids in the leaves of several edible wild plants has recently been reported. In this study, six edible wild species were selected in order to establish the fatty acid compositions in their leaf lipids. Thus, young leaves from Amaranthus viridis L.(blet), Chenopodium album L. (goosefoot), Crithmum maritimum L. (rock samphire), Plantago major L. (plantain), Portulaca oleracea L. (purslane) and Verbena officinalis L. (vervain) yielded 1.50, 2.20, 3.02, 1.46, 3.81, and 2.28 g of lipids per 100 g dry plant material. Silica gel chromatography yielded 0.64 g (Plantago major) to 2.19 g (Crithmum maritimum) neutral lipids, 0.37 g (Plantago major) to 1.60 g (Portulaca oleracea) glycolipids, and 0.26 g (Crithmum maritimum) to 0.57 g (Verbena officinalis) phospholipids per 100 g (dry weight). Gas chromatography (GC) showed the major fatty acids to be 18 : 3ω3, 18 : 2ω6 and 16 : 0 in all fractions, with high concentrations of 18 : 3ω3 in the glycolipid fraction. GC-mass spectrometric analyses did not reveal the presence of unusual fatty acids. Carotenes were found in high concentrations, ranging from 30.5 mg/100 g (Chenopodium album) to 89.2 mg/100 g (Portulaca oleracea). The analyzed plants are rich sources of essential fatty acids (18 : 2ω6 and 18 : 3ω3) and also of carotenes. Received: 29 October 1998     

Phytoestrogenic activity of ethanol extract from Korean wild vegetable Disporum uniflorum

The aim of this study was to examine the estrogenic effect of a Korean wild vegetable, Disporum uniflorum Baker. The ethanolic extract from D. uniflorum (DUE) showed a potent estrogenic activity in MCF-7 cells. After the bioassay-guided fractionation from DUE, the ethyl acetate fraction (DUF) was discovered as the active fraction responsible for the estrogenic activity. Luteolin was one of major active components of DUF, and it could be considered as a marker compound for standardization of the activity. Both DUE and DUF induced the transactivation of estrogen response element (ERE) and cell proliferation in MCF-7 cells. DUF also exerted the estrogen signaling via the phosphorylations of estrogen receptor (ER) α at Ser¹¹⁸ and extracellular signal-regulated kinase 1/2 (ERK1/2). Based on this study, therefore, DUE and DUF could be potential candidates of functional food materials for the prevention and alleviation of postmenopausal symptoms.     

Inhibitory effects of fruit extracts on nitric oxide-induced proliferation in MCF-7 cells

Nitric oxide is a free radical involved in the pathogenesis of cancer by increasing tumour vascularization and metastasis. Studies using nitric oxide inhibitors have shown decrease in tumour growth and a role in cancer therapy. To analyse the effect of fruits on nitric oxide, we carried out experiments using a nitric oxide donor on the breast cancer cell line, MCF-7. Proliferating MCF-7 cells were treated with the methanolic extract of the fruits. The inhibitory activity of fruit extracts on cell proliferation was measured using the MTT assay. Chiku and dragon fruit showed high inhibitory activity when compared to the other fruits tested. The total polyphenol and flavonoid content and nitric oxide scavenging activity were found to be high in pomegranate, chiku, litchi, durian, grape and apple. This study shows that phytochemicals present in fruits scavenge nitric oxide and inhibit MCF-7 cell proliferation.     

食药用大型真菌抗氧化活性菌株的筛选及其培养条件优化

对10种野生食药用大型真菌进行具有抗氧化活性菌株的筛选,并对高效抗氧化活性菌株进行发酵培养条件的优化,为将其投入工业化生产提供依据。以发酵粗提液的DPPH自由基清除率为指标,采用单因素和正交试验法优化大型真菌液体发酵的培养条件,并验证。结果表明,在供试的10种真菌中,有4株具有良好的抗氧化活性,占40%,其中以木耳Auricuiaria auricular CZSWXY0012的抗氧化活性为最高。最优的发酵培养条件为:葡萄糖25g/L,酵母膏2g/L,MgSO40.2g/L,CuSO4 6 mg/L,K2HPO4 3.2g/L,pH 6.0,温度27℃,装液量100mL/250mL,发酵培养8d。野生食药用大型真菌为天然抗氧化剂的开发和利用提供了宝贵的资源。     

Antibacterial activity of extracts from some edible plants commonly consumed in Asia

Extracts of edible plants (26 species) from China, Japan, Thailand and Yemen were screened for their antibacterial activity against Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Escherichia coli and Salmonella infantis. Buffered methanol (80% methanol and 20% PBS) and acetone extracted inhibitory substances against tested bacteria from 16 plants, as revealed by the disc assay. The minimum inhibitory concentrations (MICs) of extracts determined by the agar dilution method ranged from 165 to 2640 mg l⁻¹. The most sensitive microorganism to extracts from Azadirachta indica, Cinnamomum cassia, Rumex nervosus, Ruta graveolens, Thymus serpyllum and Zingiber officinale was B. cereus, with MIC of 165 to 660 mg l⁻¹. E. coli and S. infantis were only inhibited by Cinnamomum cassia extracts at the highest MIC (2640 mg l⁻¹). L. monocytogenes (Tottori) was more resistant than the ATCC 7644 strain to extracts from Ruta chalepensis, Artemisia absinthium and Cissus spp. EDTA (0.85 mM) reduced the MICs of Cinnamomum cassia and Cissus rotundifolia by at least 50% when tested against E. coli, S. infantis, S. aureus and L. monocytogenes.     

Antimicrobial activity of extracts of edible wild and cultivated mushrooms against foodborne bacterial strains

The antimicrobial activity of aqueous, methanol, hexane, and ethyl acetate extracts from edible wild and cultivated mushrooms against nine foodborne pathogenic bacterial strains (Escherichia coli O157:H7, Salmonella Enteritidis, Shigella sonnei, Vibrio parahaemolyticus, Yersinia enterocolitica, Bacillus cereus, Clostridium perfringens, Listeria monocytogenes, and Staphylococcus aureus) was screened with a disk diffusion assay. Twenty-nine of the 48 species tested had antimicrobial activity. Methanol, ethyl acetate, and aqueous extracts accounted for 92.8% of the positive assays, whereas the hexane extracts accounted for only 7.2%. Gram-positive bacteria were more sensitive than gram-negative bacteria to fungal extracts, and C. perfringens was the most sensitive microorganism. Aqueous extracts from Clitocybe geotropa and Lentinula edodes had the highest antimicrobial activity against all the bacterial strains tested.     

植物性食品原料中单萜类化合物形成机理及生物活性综述

单萜类化合物具有独特的香味和生物活性,其广泛应用于食品、化妆品、医药等众多领域,但是目前天然存在的含量较少,因此,单萜类化合物的形成机理成为急需解决的问题。该文对植物性食品原料中单萜类化合物的分类、香气特征、形成机理及其生物活性进行了综述。对其应用前景进行了展望,以期为单萜类化合物的应用和生产提供理论基础。     

Antioxidant activity of some edible plants of the Turkmen Sahra region in northern Iran

The antioxidant properties of 10 edible plants of the Turkmen Sahra region in Golestan province in northern Iran, including Allium paradoxum, Allium rubellum, Foeniculum vulgare, Mentha longifolia, Origanum vulgare, Prunus divaricata, Rubus sanctus, Rumex tuberosus, Satureja mutica and Spinacia turkestanica were evaluated by four different methods; free radical scavenging using 2,2-diphenyl-1-picrylhydrazyl (DPPH), evaluation of xanthine-oxidase activity, inhibition of lipid peroxidation by the ferric thiocyanate method, and the deoxyribose degradation assay. All species tested except A. paradoxum and P. divaricata showed antioxidant activity at least in one assay.     

Antiproliferative activity of peptides prepared from enzymatic hydrolysates of tuna dark muscle on human breast cancer cell line MCF-7

To produce and identify antiproliferative peptides, two commercial enzymes, papain (PA) and Protease XXIII (PR) were used to hydrolyse tuna dark muscle byproduct, and the protein hydrolysates were purified, before being evaluated for antiproliferative activities against human breast cancer cell line MCF-7. The results showed that the peptide fractions with the molecular weight ranging from 390 to 1400 Da possessed the greatest antiproliferative activity. The amino acid sequences of the two antiproliferative peptides isolated from PA and PR hydrolysates were Leu-Pro-His-Val-Leu-Thr-Pro-Glu-Ala-Gly-Ala-Thr (1206 Da) and Pro-Thr-Ala-Glu-Gly-Gly-Val-Tyr-Met-Val-Thr (1124 Da), whilst they show the dose-dependent inhibition effect of the MCF-7 cells with IC₅₀ values of 8.1 and 8.8 μM, respectively. We thus conclude that antiproliferative hydrolysates from tuna dark muscle byproduct may be useful ingredients in food and nutraceutical applications.     

The role of wild edible plants in household food security among transitioning hunter-gatherers: evidence from the Philippines

The Ati Negrito people, a recently settled hunter-gatherer indigenous group in the Philippines, are faced once more with the challenge of adapting to new settlements and gradually declining areas of prime food sources. The research is a documentation of uses and importance of wild edible plants the group collects and consumes as a transitioning hunter-gatherer community. Interviews were conducted with 44 female key informants representing 40 households. A total of 69 wild edible plant taxa in 31 plant families were recorded. Informant consensus revealed that many wild food plants are prioritized for their caloric content and dietary structure to complement oftentimes monotonous diets. Some of the recorded edibles were found to be non-native weedy introductions, signs of mechanisms for coping with environmental and socio-cultural changes. Preferences for certain wild edible plants also revealed that non-food factors underlay food choices. Significant factors that influence food knowledge and selection appeared to be household income, acculturation and past experiences of food scarcity. Further studies, however, have yet to provide concrete evidence that there is erosion of traditional knowledge. Regardless, determining informant confidence in selecting wild food plants has emphasized that preferences are decided based on socio-economic, cultural and ecological conditions.     

Screening procedures for clenbuterol residue determination in raw swine livers using lateral-flow assay and enzyme-linked immunosorbent assay

Clenbuterol, which may cause symptoms of increased heart rate, muscular tremors, headache, nausea, and muscular cramps in patients, has been prohibited for consumption in many countries including the European Union, the United States, and China. A rapid lateral-flow strip assay was developed in our laboratory, and results obtained with this assay were compared with those obtained with a commercial enzyme-linked immunosorbent assay (ELISA) kit for the screening of clenbuterol in raw swine liver. A total of 128 swine livers were acquired from five local markets and prepared for analysis by the lateral-flow strip assay and ELISA. Analysis was completed in 10 min with the lateral-flow strip assay and in 90 min with the ELISA. In parallel with the ELISA, the rapid detection strip produced no false-negative results but had a false-positive rate of 6.3%. Cross-reactivity of the strip was assessed and was negative after tests with clenbuterol analogues such as terbutaline, salbutamol, ractopamine, ritodrine, and fenoterol. These data suggest that a lateral-flow strip assay can be used safely as a screening method as part of a clenbuterol residue surveillance program and should be a valuable tool in the food safety field, especially in developing countries.     

Screening of some Algerian medicinal plants for the phenolic compounds and their antioxidant activity

Since recent times, there is a growing interest in the food industry and in preventive health care for the development and evaluation of natural antioxidants from medicinal plant materials. In the present work we have investigated the antioxidant potency of phenolic compounds of 11 indigenous wild plant species from the Algerian Atlas commonly used in Arab folk medicine for a wide range of conditions. The antioxidant activity of each phenolic extracts has been assessed by using the Trolox Equivalent Antioxidant Capacity (TEAC) as a chemical test, and in a dynamic way by a biological assay based on whole blood resistance to free radical aggression. Of the 11 tested plants, 2 showed prominent antioxidant activity: Anthemis arvensis and Artemisia campestris. These plants had a very high level of Trolox equivalents and induced a strong delay of free radical-induced red blood cells hemolysis compared to antioxidant references. Artemisia campestris was the best inhibitor, its effect was far stronger than that of caffeic acid and was more than three times as high as ascorbic acid and two times higher than α-tocopherol efficiency. HPLC analysis showed a good correlation between the antioxidant activity and hydroxycinnamic derivatives. These preliminary results on the in vitro protection of blood against oxidative stress emphasized the benefit of the phenolic compounds of these medicinal plants. Our results enable us to proceed towards more detailed chemical and pharmacological understanding of these plant materials and show the interest of natural antioxidant in medicinal plants for the prevention of much free radical-mediated pathology.     

A systematic survey of antioxidant activity of 30 Chinese medicinal plants using the ferric reducing antioxidant power assay

The antioxidant activities and total phenolic contents of 30 Chinese medicinal plants were evaluated using the ferric reducing antioxidant power assay and the Folin–Ciocalteu method, respectively. The Chinese medicinal plants were extracted by the traditional method, boiling in water and also in 80% methanol. A significant and linear correlation coefficient between the antioxidant activity and the total phenolic content was found in both aqueous (R² = 0.7917) and methanol (R² = 0.7584) extracts. Phenolic compounds are thus a major contributor of antioxidant activity. Comparing the extraction efficiency of the two methods, the boiling water method extracted phenolic compounds more efficiently, and antioxidant activity of the extract was higher. It was found that the Chinese medicinal plants Rhodiola sacra Fu, the stem of Polygonum multiflorum Thunb. and the root of P. multiflorum Thunb. possessed the highest antioxidant activities and thus could be potential rich sources of natural antioxidants.