野葛内生真菌的分离、鉴定及体外细胞毒活性

目的:药用植物内生真菌是一类重要的微生物资源,其代谢产物有着广泛的生物学活性。该研究拟从野葛(Pueraria lobata(Willd.)Ohwi)中分离有细胞毒活性的内生真菌。方法:组织块改良法分离内生真菌;细胞毒活性测定采用Alamar blue法;结合形态学和分子生物学方法进行菌种鉴定。结果:获得的34株内生真菌中菌株KLBMP f0027对HepG2、HO-8910、NCI-H460、SGC-7901等细胞株均有显著活性,ID50分别为437.4、460.0、542.5、771.2。而且活性产物相对稳定,对温度、pH变化及蛋白酶不敏感。代谢过程研究显示菌株KLBMP f0027的活性产物合成与细胞生长属于部分耦联关系类型。形态学和ITS-rDNA序列分析鉴定菌株为Aspergillus ostianus strain KLBMP f0027。结论:野葛内生真菌A.ostianus strain KLBMP f0027可作为细胞毒活性候选菌株进行深入研究。     

Endophytic Actinobacteria from the Brazilian Medicinal Plant Lychnophora ericoides Mart. and the Biological Potential of Their Secondary Metabolites

Endophytic actinobacteria from the Brazilian medicinal plant Lychnophora ericoides were isolated for the first time, and the biological potential of their secondary metabolites was evaluated. A phylogenic analysis of isolated actinobacteria was accomplished with 16S rRNA gene sequencing, and the predominance of the genus Streptomyces was observed. All strains were cultured on solid rice medium, and ethanol extracts were evaluated with antimicrobial and cytotoxic assays against cancer cell lines. As a result, 92% of the extracts showed a high or moderate activity against at least one pathogenic microbial strain or cancer cell line. Based on the biological and chemical analyses of crude extracts, three endophytic strains were selected for further investigation of their chemical profiles. Sixteen compounds were isolated, and 3‐hydroxy‐4‐methoxybenzamide ( 9 ) and 2,3‐dihydro‐2,2‐dimethyl‐4(1H)‐quinazolinone ( 15 ) are reported as natural products for the first time in this study. The biological activity of the pure compounds was also assessed. Compound 15 displayed potent cytotoxic activity against all four tested cancer cell lines. Nocardamine ( 2 ) was only moderately active against two cancer cell lines but showed strong activity against Trypanosoma cruzi. Our results show that endophytic actinobacteria from L. ericoides are a promising source of bioactive compounds.     

3-hydroxypropionic acid as a nematicidal principle in endophytic fungi

3- Hydroxypropionic acid was isolated by bioactivity-guided fractionation of extracts obtained from submerged cultures of several endophytic fungi isolated from above-ground plant organs. This compound showed selective nematicidal activity against the plant-parasitic nematode Meloidogyne incognita with LD50 values of 12.5-15 microg/ml. Activity against the saprophytic Caenorhabditis elegans was fivefold lower. No antimicrobial, cytotoxic or phytotoxic effects were observed. Propionic acid and D- and L-lactic acids were not active against either nematode species. Based on morphological features and ITS, 18S and 28S rDNA analyses, the producing strains were identified as Phomopsis phaseoli isolated from the leaf of a tropical tree, and four strains of Melanconium betulinum isolated from twigs of Betula pendula and B. pubescens in Germany. This is the first report of 3-hydroxypropionic acid in fungi, and of the nematicidal activity of this metabolite.     

Biological activities from extracts of endophytic fungi isolated from Viguiera arenaria and Tithonia diversifolia

A total of 39 endophytic fungi have been isolated from Viguiera arenaria and Tithonia diversifolia, both collected in S?o Paulo State, Brazil. The isolates were identified based on their ribosomal DNA sequences. The ethyl acetate (EtOAc) extracts of all endophytic fungi were evaluated for their antimicrobial, antiparasitic and antitumoral activity. Antimicrobial screening was conducted using an agar diffusion assay against three pathogenic microorganisms: Staphylococcus aureus, Escherichia coli and Candida albicans. Antiparasitic activity was determined by enzymatic inhibition of gGAPDH of Trypanosoma cruzi and adenine phosphorybosiltransferase (APRT) of Leishmania tarentolae. Antitumoral activity was tested against human T leukemia cells by the Mosmann colorimetric method. All extracts showed activity in at least one assay: 79.5% of the extracts were cytotoxic against leukemia cells, 5.1% of the extracts were active against S. aureus, 25.6% against E. coli and 64.1% against Candida albicans. Only one extract showed promising results in the inhibition of parasitic enzymes gGAPDH (95.0%) and three were found to inhibit APRT activity. The cytotoxic extract produced by the strain VA1 (Glomerella cingulata) was fractionated and yielded nectriapyrone and tyrosol. Nectriapyrone showed relevant cytotoxic activity against both human T leukemia and melanoma tumor cell lines.     

蛇足石杉中的新内生真菌及其代谢产物的分离与鉴定

从蛇足石杉内生菌的次级代谢产物中寻找活性成分,为进一步开发利用蛇足石杉药用植物资源提供了新途径,但至今其内生菌代谢产物的系统性研究较为少见。种类丰富的内生真菌普遍存在于各种植物中,但蕨类植物中内生真菌的研究较少。为了寻找蛇足石杉内生菌中的细胞毒活性成分,该研究从蛇足石杉根部分离得到一株球毛壳属(Chaetomium sp.)真菌M336,对其化学成分进行了研究。对蛇足石杉内生真菌M336采用PDA固体培养基扩大发酵,发酵物经提取及乙酸乙酯萃取后,通过正相硅胶柱色谱法、Sephadex LH-20凝胶柱色谱法、薄层制备、高效液相色谱等色谱手段对其发酵物中的化学成分进行分离纯化,利用理化性质、质谱、核磁等波谱分析技术,并结合相关文献数据鉴定化合物的结构。结果表明：从内生真菌M336发酵提取物的乙酸乙酯萃取部分分离并鉴定出8个化合物,分别为chaetoviridines F、chaetoviridines E、5′-epichaetoviridin A、5′-epichaetoviridin A、xanthoquinodins Al、xanthoquinodins A2、xanthoquinodins B1和毛壳菌素。从M336中分离得到8个化合物,化合物3有一定的抑菌作用,其余化合物有一定的细胞毒活性。该研究结果丰富了蛇足石杉内生真菌球毛壳属中的天然细胞毒活性的化合物。     

一株产紫杉醇罗汉松内生真菌的分离和鉴定

[目的]紫杉醇是重要的抗癌药物,主要从罗汉松等植物中提取,为了保护罗汉松等种质资源,本文从罗汉松植株中分离产紫杉醇内生真菌,并对内生真菌所产紫杉醇的抗肿瘤活性进行了分析.[方法]采用组织块法自罗汉松的根、茎、叶等组织中分离内生真菌;通过四唑蓝(Methyl ThiazolylTetrazolium,MTT)比色法筛选有抗肿瘤活性的内生真菌菌株,通过薄层层析(Thin Layer Chro-matography,TLC)和高效液相色谱(High Performance Liquid Chromatography,HPLC)对内生真菌所产活性物质进行鉴定;采用抽提法抽提内生真菌所产紫杉醇,应用Vero细胞对抽提的紫杉醇的活性进行了分析.[结果]从罗汉松属(Podocrapus)植物中分离到155株内生真菌,其中28株内生真菌具有较高的抑癌活性.将其中一株菌株A2命名为EPTP-1,经形态学和分子分类学分析鉴定为烟曲霉(Aspergillus fumigatus).菌株EPTP-1中抽提的紫杉醇5.553μg/L～555.3 μg/L作用24h表现出明显的致细胞凋亡作用.菌株EPTP-1发酵5天时紫杉醇的产率为0.5578±0.0294 mg/L.[结论]从罗汉松中分离到了一株产紫杉醇内生真菌EPTP-1,可作为紫杉醇类药物工业化生产的候选菌株.     

两株海洋真菌的鉴定及其次级代谢产物抑制烟草花叶病毒及抗肿瘤活性

摘要：【目的】通过对2株活性海洋真菌发酵产物提取物抑制烟草花叶病毒和抗肿瘤活性进行研究,为进一步得到活性纯品化合物作为抗病毒及抗肿瘤的先导化合物奠定基础。【方法】菌株发酵产物的粗提物是通过甲醇浸取并在真空条件下蒸干得到的。粗提物中溶于水的部分为水溶性部分,不溶于水的部分为脂溶性部分。通过间接酶联免疫法检测样品抑制烟草花叶病毒的活性,通过四甲基偶氮唑盐微量酶反应比色法（MTT法）检测样品抗肿瘤活性,通过形态及ITS rDNA序列法进行菌株鉴定。【结果】两株海洋真菌抑制烟草花叶病毒活性和抗肿瘤的活性均较高。分子鉴定结果显示,两株真菌分别与Penicillium oxalicum 和 Neosartorya fischeri 的同源性极高。菌株0312F1发酵液的水溶性部分具有抗病毒及抗肿瘤活性,菌株1008F1发酵液的脂溶性部分具有抑制烟草花叶病毒活性,而水溶性部分具有抗肿瘤活性。【结论】菌株0312F1和菌株1008F1发酵液的提取物抑制烟草花叶病毒的活性部位不同,而抗肿瘤活性部位相同。菌株0312F1发酵液提取物的水溶性活性部位对肝癌细胞BEL-7404的抑制效果比对胃癌细胞SGC-7901的抑制效果明显,而菌株1008F1发酵液提取物的水溶性活性部位对胃癌细胞SGC-7901的抑制效果比对肝癌细胞BEL-7404的抑制效果明显。     

Hormonemate,a new cytotoxic and apoptosis-inducing compound from the endophytic fungus Hormonema dematioides. I. Identification of the producing strain,and isolation and biological properties of hormonemate

In a search for new fungal compounds inducing apoptosis of the colon cancer derived cell line COLO-320, hormonemate (1) was purified from fermentations of an endophytic fungus isolated from living needles of a Pinus species. The producing strain was identified as Hormonema dematioides by microscopy and ITS rDNA sequence analysis. The structure of hormonemate was determined by spectroscopic methods. The compound exhibited cytotoxic effects against the human colon tumor cell lines COLO-320, DLD-1 and HT-29 as well as five other human cell lines (HL-60, JURKAT, HEP-G2, MCF-7, HeLa S3). It also induced apoptosis in COLO-320 cells as detected by a caspase-activity assay and morphological changes, and it triggered morphological and physiological differentiation of HL-60 cells into granulocytes, which subsequently died by apoptosis.     

盐角草内生真菌分离鉴定及抑制水产腐败细菌菌株的筛选

盐角草是一种耐盐植物,有重要的食用、药用价值.为研究盐角草的内生真菌及其活性次生代谢产物的多样性,该文对采集于广西北部湾沿海盐角草的内生真菌进行分离纯化,采用RAPD对内生真菌多样性进行分析,采用ITS基因序列对内生真菌进行鉴定,并对内生真菌提取物抑制等3种水产腐败细菌的活性进行筛选.结果表明:(1)从北部湾盐角草植物...     

Evaluation of in vitro alpha-glucosidase inhibitory,antimicrobial, and cytotoxic activities of secondary metabolites from the endophytic fungus,Nigrospora sphaerica,isolated from Helianthus annuus

This study aimed to evaluate alpha-glucosidase inhibition and antimicrobial activity as well as cytotoxic activity of extracts from the endophytic fungus, Nigrospora sp., isolated from leaves of Helianthus annuus, which is widely cultivated for food and used as a medicinal plant. The fungus (TSU-CS003) was identified based on internal transcribed spacer ribosomal DNA sequences and fungal biomass, and fermentation broth was subjected to extraction by solvents (hexane and ethyl acetate). All extracts were tested for their antimicrobial activity, alpha-glucosidase inhibition, and cytotoxicity activity. In addition, the active extract was analyzed by using gas chromatography mass spectrometry (GC-MS) TSU-CS003 was identified as Nigrospora sphaerica. The fermentation broth extract (BE) showed strong antimicrobial activity against Staphylococcus aureus and methicillin-resistant S. aureus (Gram-positive bacteria) with minimum inhibitory concentration (MIC) values in the range of 16–32 μg/mL and a few yeasts with MIC values ranging from 64 to 128 μg/mL, especially Talaromyces marneffei with an MIC value of 4 μg/mL. The effects of BE were observed by SEM. The results showed that this extract affected the cell morphology of T. marneffei. The half-maximal inhibitory concentration (IC50) of BE from alpha-glucosidase inhibition was recorded as 17.25 μg/mL and also showed significant cytotoxicity against A549 human cancer cell lines with an IC50 value of 22.41 μg/mL. Furthermore, BE was analyzed by using GC-MS and divided into three main compounds, including 5-pentyldihydrofuran-2(3H)-one, (Z)-methyl 4-(isobutyryloxy)but-3-enoate, and 2-phenylacetic acid. This was the first report of the endophytic fungus N. sphaerica from H. annuus. It is a potential source of active metabolites, which gave the strong antifungal activity, antioxidant activity, and cytotoxicity to A549 cancer cell lines.     

广西柳树桑寄生内生真菌的分离鉴定与抗肿瘤活性菌株筛选

该研究从广西钦州市采集健康的柳树桑寄生的根、茎和叶中分离并纯化内生真菌,对真菌进行形态学鉴定,提取内生真菌的DNA,采用真菌ITS序列对内生真菌进行分子鉴定。利用A549和H460细胞作为抗肿瘤活性指示细胞,采用MTT法测定真菌乙酸乙酯提取物的抗肿瘤活性。经过初步分离分析,从柳树桑寄生中纯化出27株内生真菌,经鉴定它们分别属于7个目9个属15个种。拟盘多毛孢属和间座壳属为优势属,其中拟盘多毛孢属全部定植于寄生根;其次为新壳梭孢属、拟茎点霉属和球座菌属,各分离到3株;其他包括青霉属、镰刀菌属、炭疽菌属和派伦霉属,各分离到1株。抗肿瘤活性研究表明,有一株与Pestalotiopsis protearum的ITS序列相似性达100%的拟盘多毛孢属菌株Gen24表现有抑制肿瘤细胞A549和H460生长的特性,在真菌乙酸乙酯浸提物浓度为800μg·mL~(-1)时,对A549细胞的抑制率达到了56.92%,对H460细胞的抑制率达到了70.11%。该研究结果表明广西柳树桑寄生内生真菌较丰富,在寄主中的分布表现了一定的组织特异性,而且还存在一些具有抗肿瘤活性的菌株及其活性物质可供进一步深入研究。     

Molecular profiling of marine endophytic fungi from green algae: Assessment of antibacterial and anticancer activities

Bioactive natural metabolites, especially from the marine endophytic fungi, are largely unexplored. Endophytic fungi are being increasingly recognized as a group of organisms that produce novel metabolites of industrial importance. This study investigated the anticancer and antibacterial potential of the marine algal endophyte, Penicillium chrysogenum. The different organic solvent extracts of the endophytic fungi grown on different growth medium were analyzed for anticancer and antibacterial activities. The highest inhibitory activity was observed for the ethyl acetate (EA) extract of the culture filtrate grown in potato dextrose broth (PDB) for 21 days, against the tested human breast cancer cell (MCF-7) line. Similarly, the PDB-EA extract showed an appreciable activity against the human pathogens. The biochemical analysis of the Cha EA metabolites revealed terpenoids, steroids, phenolics and flavones. Gas Chromatography (GCMS) data revealed several bioactive compounds such as anthraquinone and cinnamic acid. The Cha EA extract induced membrane damage and thus, apoptosis in MCF-7cells. The secondary metabolites produced by these marine endophytic fungi have contributed to considerable anticancer and antimicrobial activities and hence, this study is an evidence of potential sources of antimicrobial and anticancer compounds from Penicillium chrysogenum.     

Qualitative HPLC‐DAD/ESI‐TOF‐MS Analysis,Cytotoxic, and Apoptotic Effects of Croatian Endemic Centaurea ragusina L. Aqueous Extracts

Centaurea ragusina L., an endemic Croatian plant species, revealed a good cytotoxic activity of aqueous extracts (AE) on human bladder (T24) and human glioblastoma (A1235) cancer cell lines. The chemical constituents were tentatively identified using high performance liquid chromatography HPLC‐DAD/ESI‐TOF‐MS in negative ionization mode. The main compounds of herba extract were sesquiterpene lactones: solstitialin A 3,13‐diacetate and epoxyrepdiolide; organic acid: quinic acid. The main compounds of flower extract were organic acids: quinic acid, citric acid, and malic acid; sesquiterpene lactone: cynaropicrin; phenolic compounds: chlorogenic acid and phenylpropanoid: syringin. The AE of C. ragusina were investigated for correlation of their effects on human bladder (T24) and human glioblastoma (A1235) cancer cell lines using the MTT assay. Although both extracts showed significant dose‐ and time‐dependent cytotoxic activity against both cancer cell lines, the flower extract exhibited slightly higher activity. In order to determine type of cell death induced by treatment, cell lines were exposed subsequently to a treatment with both flower and herba AE. The majority of the cells died by induced apoptosis treatment. Flower AE (26.25%), compared to a leaf AE (22.15%) showed slightly higher percentage of an apoptosis in T24 cells, when compared to a non‐treated cells (0.04%).     

Cytotoxicity and apoptosis induction of some selected marine bacteria metabolites

AIMS: To study the potential apoptosis effects of cytotoxic marine bacterial metabolites on human HeLa cell line. METHODS AND RESULTS: After HeLa cells were routinely cultured, tetrazolium-based colorimetric assay for cytotoxicity was performed to screen the marine bacteria extracts showing 12 strains active. To find the potential active strain with apoptosis mechanism, a battery of apoptosis assays, including AO/EB staining, TUNEL assay (terminal-deoxynucleotidyl transferase mediated nick end labelling), gel electrophoresis and flow cytometry, were used to determine whether apoptosis was involved in HeLa cell cytotoxicity of marine bacterial extracts. The results indicated that four strains could induce cell shrinkage, cell membrane blebbing, formation of apoptotic body and DNA fragmentation. CONCLUSIONS: Crude extracts of 12 of 153 strains of marine bacteria showed cytotoxic effects with ID50 ranged from 77.20 to 199.84 microg ml(-1), in which eight strains of bacteria were associated bacteria. The metabolites in the strains of QD1-2, NJ6-3-1, NJ1-1-1 and SS6-4 were able to induce HeLa cells apoptosis. Furthermore, the assessment by flow cytometry indicated that the hypodiploid apoptotic cells increased in a time-dependent manner, suggesting that induced apoptosis occurred from 24 h to 48 h after the extracts treatment. SIGNIFICANCE AND IMPACT OF THE STUDY: Our results suggested that the compounds from fermentation in these four marine bacterial strains could be candidates for developing apoptosis specific anti-tumour agents with lower toxicity. This study indicated that associated marine bacteria could be good source to find cytotoxic metabolites, and some cytotoxic marine bacterial metabolites could have apoptosis mechanisms.     

Molecular and functional characterization of endophytic fungi from traditional medicinal plants

This study reports the isolation of 63 endophytic fungal isolates from two traditional medicinal plants, Ocimum sanctum and Sapindus detergens from different locations of Amritsar, India. The functional characterization of the fungi for their ability to produce anti bacterial and anti cancer agent was carried out. Sixteen strains were characterized at molecular level by sequencing the amplified ITSI-5.8-ITSII region of rDNA. The phylogenetic tree resolved the endophytic fungi into different clades. The fungal endophytes belonging to order Pleosporales (Alternaria sp., Phoma sojicola and Exserohilum sp.) were functionally versatile as they produced diverse biomolecules including antibacterial agent active against Mycobacterium smegmatis, as well as cytotoxic activity against different human cancer cell lines of lung, ovary, breast, prostrate, neuroblastoma and colon.     

Antibacterial, antifungal and cytotoxic activity of terrestrial cyanobacterial strains from Serbia

Cyanobacteria are known to be a rich source of biologically active compounds some of which can have pharmaceutical importance. In this work we present the screening results of cyanobacterial strains for their antibacterial, antifungal, and cytotoxic activity. Cyanobacterial strains were isolated from various soil types in province of Vojvodina and Central Serbia, Republic of Serbia. The screening included 9 strains of Anabaena and 9 strains of Nostoc. Both, extracellular products (from the culture liquid) and cellular crude lipophilic extracts were tested against 13 bacterial strains and 8 fungal strains. Cytotoxic activity was tested against three human cell lines. Methanol extracts were prepared according to ?stensvik. Antibacterial and antifungal activities were determined measuring inhibition zone, 48 h after inoculation. The cytotoxic activity was determined by sulforhodamine B (SRB) colorimetric assay. Of all cyanobacterial strains tested, 52% showed some antifungal and 41% antibacterial activity. Two out of six tested strains possessed cytotoxic activity. The cytotoxic activity of Anabaena strain S12 was found both in culture liquid and crude cell extract. It occurred specifically between the 21st and 42nd day of cultivation against HeLa and MCF7 cells, but had no activity against cell line derived from a healthy tissue. A high percentage of the active strains among the tested strains justify the effort of screening cyanobacteria that are isolated from terrestrial environments. The most promising strains for the fur- ther study are Anabaena strain S12 which showed strong cytotoxic and antibacterial activity and Ana- baena strain S20 which produces a potent antifungal compound. The future work, besides further screening and chemical identification of the active compounds, should also include the development of culture techniques that would lead to more efficient production of biologically active compounds.     

Comparative analysis of the cytotoxic activity of extracts from different parts of A. absinthium L. on breast cancer cell lines and correlation with active compounds concentration

The aim of the present study was to compare the cytotoxicity of different extracts of the plant Artemisia absinthium on breast cancer cell lines and to establish the correlation between the cytotoxicity and the active constituent’s level in these extracts. The cytotoxicity of the extracts was evaluated on the breast cancer cell lines, MCF-7 and MDA MB-231 by MTT assay and LDH release assay. An HPTLC method was developed for the simultaneous estimation of active constituents, that is, artemisinin, artemisinic acid, and alpha-thujone in different parts of A. absinthium. The whole extract was best among all the extracts tested with least IC₅₀ value and high LDH release that is, 491.19?µg/µL with 27.92% for MCF-7 and 459.97?µg/µL with 29.43% for MDA MB-231 cell lines respectively. Although, the concentration of all three quantified active compounds was higher in the extract from aerial part; however, the whole extract showed the best cytotoxicity among all extracts evaluated on the breast cancer cell lines. Surprisingly, our results demonstrate that the quantified active compounds were not solely responsible for the cytotoxic activity of the plant parts and further studies may be conducted to identify the compounds with synergistic, allosteric or antagonistic effects.     

Lichens: a promising source of antibiotic and anticancer drugs

Lichens are symbiotic associations between fungi and a photosynthetic alga and/or cyanobacteria. Lichenized fungi have been found to produce a wide array of secondary metabolites, most of which are unique to the lichenized condition. These secondary metabolites have shown an impressive range of biological activities including antibiotics, antifungal, anti-HIV, anticancer, anti-protozoan, etc. This review focuses primarily on the antibiotic and anticancer properties of lichen secondary chemicals. We have reviewed various publications related to antibiotic and anticancer drug therapies emphasizing results about specific lichens and/or lichen compounds, which microbes or cancer cells were involved and the main findings of each study. We found that crude lichen extracts and various isolated lichen compounds often demonstrate significant inhibitory activity against various pathogenic bacteria and cancer cell lines at very low concentrations. There were no studies examining the specific mechanism of action against pathogenic bacteria; however, we did find a limited number of studies where the mechanism of action against cancer cell lines had been explored. The molecular mechanism of cell death by lichen compounds includes cell cycle arrest, apoptosis, necrosis, and inhibition of angiogenesis. Although lichens are a reservoir for various biologically active compounds, only a limited number have been tested for their biological significance. There is clearly an urgent need for expanding research in this area of study, including in depth studies of those compounds which have shown promising results as well as a strong focus on identifying specific mechanisms of action and extensive clinical trials using the most promising lichen based drug therapies followed by large scale production of the best of those compounds.     

Natural daucane sesquiterpenes with antiproliferative and proapoptotic activity against human tumor cells

Plants of the genera Ferula and Ferulago are known for their complex content in bioactive secondary metabolites such as coumarins, phenylpropanoids, and sesquiterpenes. We used the ground parts of Ferula communis subsp. communis, Ferula glauca subsp. glauca and Ferulago campestris as natural sources for the isolation of four coumarins (CU-1 to CU-4), two phenylpropanoids (PE-1 and PE-2), one polyacetylene (PA-1) and 16 daucane esters (DE-1 to DE-16). The cytotoxic activity of the isolated compounds was evaluated against a panel of seven human tumor cell lines. Fourteen of the daucane derivatives showed antiproliferative activity at least against one of the human tumor cell lines tested, four compounds (DE-5, DE-8, DE-11, and DE-16) were active against all the tested cell lines. Among them DE-11 was the most cytotoxic compound against HeLa (4.4 ± 0.7 μM), A549 (2.8 ± 1.4 μM), HL-60 (2.6 ± 0.4 μM), K562 (26.5 ± 6.0 μM) RS 4;11 (1.7 ± 0.3 μM) and SEM (2.4 ± 0.1 μM) cell lines, while DE-8 was the most active against Jurkat (3.3 ± 0.8 μM). Preliminary structure-activity relationship suggests that the most active compounds in the daucane series present the trans fusion of the penta- and hepta-atomic cycles, and lipophylic ester groups linked to position 6. Isomeric derivatives such as DE-8 and DE-9 or DE-3, DE-4, and DE-5 exhibited significant differences in their IC(50) supporting that the β orientation for the ester group in the position 2 enhances the cytotoxic activity. Furthermore, the pro-apoptotic effect of the most active compounds evaluated in Jurkat cell line showed that these compounds are able to induce apoptosis in a time and concentration-dependent manner. Our findings suggest the potential role of daucane derivatives as models for the development of proapoptotic compounds.     

Actinomycetes from Moroccan habitats: isolation and screening for cytotoxic activities

In our screening for actinomycetes showing cytotoxic activities, 8 samples were collected from various Moroccan habitats, 136 isolates were tested for their capacity to produce antibacterial compounds against gram positive bacteria. Thirty-seven strains of these isolates were active against Gram-positive bacteria. Using the following steps of primary screening: antibacterial activity, confrontation between the isolates and toxicity to Artemia salina; fifteen different isolates were used for further investigation. The aqueous extracts of Streptomyces sp. T5 and Streptomyces sp. AS8 were selected for their cytotoxic activity against Hep2, BSR and P815 cell lines, and two active compounds were observed on HPLC. The two isolates exhibited high activity against human cancer cell lines and were inactive on PBMC cell lines. Furthermore, the Streptomyces sp. T5 extract showed a proliferative activity.