• Applied Biological Chemistry
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• v.48 no.1
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• pp.1-15
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• 2005

Pathogens, insects and weeds have significantly reduced agricultural productivity. Thus, to increase the productivity, synthetic agricultural chemicals have been overused. However, these synthetic compounds that are different from natural products cannot be broken down easily in natural systems, causing the destruction of soil quality and agricultural environments and the gradually difficulty in continuous agriculture. Now agriculture is faced with the various problems of minimizing the damage in agricultural environments, securing the safety of human health, while simultaneously increasing agricultural productivity. Meanwhile, plants produce secondary metabolites to protect themselves from external invaders and to secure their region for survival. Plants infected with pathogens produce antibiotics phytoalexin; monocotyledonous plants produce flavonoids and diterpenoids phytoalexins, and dicotylodoneous plant, despite of infected pathogens, produce family-specific phytoalexin such as flavonoids in Leguminosae, indole derivatives in Cruciferae, sesquitepenoids in Solanaceae, coumarins in Umbelliferae, making the plant resistant to specific pathogen. Growth inhibitor or antifeedant substances to insects are terpenoids pyrethrin, azadirachtin, limonin, cedrelanoid, toosendanin and fraxinellone/dictamnine, and terpenoid-alkaloid mixed compounds sesquiterpene pyridine and norditerpenoids, and azepine-, amide-, loline-, stemofoline-, pyrrolizidine-alkaloids and so on. Also plants produces the substances to inhibit other plant growths to secure the regions for plant itself, which is including terpenoids essential oil and sesquiterpene lactone, and additionally, benzoxazinoids, glucosinolate, quassinoid, cyanogenic glycoside, saponin, sorgolennone, juglone and lots of other different of secondary metabolites. Hence, phytoalexin, an antibiotic compound produced by plants infected with pathogens, can be employed for pathogen control. Terpenoids and alkaloids inhibiting insect growth can be utilized for insect control. Allelochemicals, a compound released from a certain plant to hinder the growth of other plants for their survival, can be also used directly as a herbicides for weed control as well. Therefore, the use of the natural secondary metabolites for pest control might be one of the alternatives for environmentally friendly agriculture. However, the natural substances are destroyed easily causing low the pest-control efficacy, and also there is the limitation to producing the substances using plant cell. In the future, effects should be made to try to find the secondary metabolites with good pest-control effect and no harmful to human health. Also the biosynthetic pathways of secondary metabolites have to be elucidated continuously, and the metabolic engineering should be applied to improve transgenics having the resistance to specific pest.

• The Plant Pathology Journal
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• v.36 no.5
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• pp.491-496
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• 2020

An understanding of the contribution of secondary metabolites (SMs) to the antagonistic and biocontrol activities of bacterial biocontrol agents serves to improve biocontrol potential of the strain. In this study, to evaluate the contribution of each SM produced by Pseudomonas fluorescens NBC275 (Pf275) to its antifungal and biocontrol activity, we combined in silico analysis of the genome with our previous study of transposon (Tn) mutants. Thirteen Tn mutants, which belonged to 6 biosynthetic gene clusters (BGCs) of a total 14 BGCs predicted by the antiSMASH tool were identified by the reduction of antifungal activity. The biocontrol performance of Pf275 was significantly dependent on 2,4-diacetylphloroglucinol and pyoverdine. The clusters that encode for arylpolyene and an unidentified small linear lipopeptide influenced antifungal and biocontrol activities. To our knowledge, our study identified the contribution of SMs, such as a small linear lipopeptide and arylpolyene, to biocontrol efficacy for the first time.

• Preventive Nutrition and Food Science
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• v.11 no.2
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• pp.133-139
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• 2006

There is great demand of nutraceutical secondary metabolites in the world so as to feed the population by improving agricultural production with new varieties of food crops but what is still more important is to add nutrition into the food. Physalis minima, plant of Solanaceae family, contain certain secondary metabolites which enhance the over all metabolic functions of the body. Withasteroids are one of such phytochemicals that are generally regarded as safe. These chemicals are almost monopoly of the plants of Solanaceae. The leaves, stem and roots of P. minima have been examined to yield several steroids, identification of which has been discussed in this paper. These withasteroids contribute to the potential nutraceutical and health function value since incorporation of withanolides in the diet may prevent or decrease the growth of tumors in humans.

• Mycobiology
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• v.40 no.3
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• pp.147-150
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• 2012

This paper provides a description of Opegrapha herbarum, Opegrapha viridis and Phaeographis subdividens, all newly identified in the Republic of Korea. The characteristic features of O. herbarum include Varia-type asci, Subelevata-type ascospores, a lack of secondary metabolites and a saxicolous habitat. O. viridis possesses Calcarea-type asci, Vulgata-type ascospores and no chemicals in the thallus. P. subdividens is recognizable by its curved to sinuous lirellae, divergent labia, a brown and uniformly thick proper exciple which is open at its base, 3~4-septate ascospores, and lack of secondary metabolites. All three taxa are now reported to exist on Bogil Island in the Republic of Korea.

• Microbiology and Biotechnology Letters
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• v.22 no.5
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• pp.459-466
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• 1994

Virginiae butanolide C(VB-C) is one of the butyrolactone autoregulators, which triggers the production of virginiamycin in Streptomyces virginiae. Streptomyces longwoodensis was selected as a test strain to investigate new VB-C functions. When 100 ng/ml of the synthetic VB-C was added into the culture at 5 hour and 0 hour, the initial production time of antibiotics and a dark blue pigment were shortened by 4~6 hours and 2~4 hours, respectively. HPLC analysis revealed the production of several new antibiotics by VB-C addition. In the SDS-PAGE analysis of the total protein from mycelium several new protein bands showed up and the amounts of certain protein bands increased in the presense of VB-C. The existence of specific VB-C binding protein was confirmed from S. longwoodensis in relation to VB-C signal transduction. These results suggest that the VB-C might have an ability to induce the production of secondary metabolites in Streptomy- ces longwoodensis.

• Plant Biotechnology Reports
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• v.2 no.2
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• pp.93-112
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• 2008

Medicinal and aromatic plants (MAPs) are important sources for plant secondary metabolites, which are important for human healthcare. Improvement of the yield and quality of these natural plant products through conventional breeding is still a challenge. However, recent advances in plant genomics research has generated knowledge leading to a better understanding of the complex genetics and biochemistry involved in biosynthesis of these plant secondary metabolites. This genomics research also concerned identification and isolation of genes involved in different steps of a number of metabolic pathways. Progress has also been made in the development of functional genomics resources (EST databases and micro-arrays) in several medicinal plant species, which offer new opportunities for improvement of genotypes using perfect markers or genetic transformation. This review article presents an overview of the recent developments and future possibilities in genetics and genomics of MAP species including use of transgenic approach for their improvement.

• Natural Product Sciences
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• v.21 no.4
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• pp.261-267
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• 2015

Compared to their terrestrial and marine counterparts, little is known about the capacity of freshwater-derived actinomycete bacteria to produce novel secondary metabolites. In the current study, we highlight the disparities that exist between cultivation-independent and -dependent analyses of actinomycete communities from four locations in Lake Michigan sediment. Furthermore, through phylogenetic analysis of strains isolated from these locations, we identified a Streptomyces sp., strain B025, as being distinct from other Streptomyces spp. isolated from sediment. Upon fermentation this strain produced a rare class of eight-membered lactone secondary metabolites, which have been for their antitumor properties. We used spectroscopic and chemical derivitization techniques to characterize octalactin B (1) in addition to its corresponding novel, unnatural degradation product (2).

• Journal of Plant Biotechnology
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• v.49 no.1
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• pp.3-14
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• 2022

Leonotis nepetifolia (L.) R. Br, commonly called dagga, klip dagga, or lion's ear, has been used to effectively treat various diseases and other health problems for a long time because of its antimicrobial, anti-inflammatory, antioxidant, and analgesic activities. Several studies have attributed these biological activities to L. nepetifolia's constituent secondary metabolites, such as alkaloids, phenolics, flavonoids, tannins, steroids, glycosides, coumarins, anthocyanins, and saponins. This review aims to examine the evidence-based ethnopharmacological uses of L. nepetifolia in the treatment of bronchial asthma, diarrhea, skin diseases, malaria, burns, cancer, diabetes mellitus, and rheumatism. However, although L. nepetifolia has great potential to treat these diseases, further isolation and identification of its therapeutic phytochemical constituents are required. In addition, the performance of its extracts and phytochemicals should be thoroughly tested in preclinical and clinical trials in order to ascertain their safety and efficacy, which will prove valuable in developing new medicines.

• Mass Spectrometry Letters
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• v.14 no.2
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• pp.25-35
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• 2023

Plants are a traditional source of many chemicals used as biochemical, flavors, food, color, and pharmaceuticals in various countries, especially India. Most herbal medicines and their derivatives are often made from crude extracts containing a complex mixture of various phytochemical chemical components (secondary metabolites of the plants). This study aimed to identify bioactive compounds from the different parts of the plant from the ethanolic extract of Gymnema sylvestre, Senna auriculata, and Cissus quadrangularis (leaves, flower, stem) by gas chromatography-mass spectroscopy (GC-MS). The gas chromatography - mass spectrometry analysis revealed the presence of various compounds like 3,4-dimethylcyclohexanol, hexanoic acid, D-mannose, and N-decanoic acid. Hence, the Gymnema sylvestre, Senna auriculata, and Cissus quadrangularis may have chemopreventive, anti-cancer, anti-microbial activity, antioxidant, anti-diabetic activity, anti-inflammatory, and antifungal due to the presence of secondary metabolites in the ethanolic extract. These phytochemicals are supported for traditional use in a variety of diseases.

• Mycobiology
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• v.51 no.6
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• pp.436-444
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• 2023

Aspergillus species play a crucial role in terrestrial environments as degraders and are well known for producing various secondary metabolites. Recently, Aspergillus species have been discovered in marine environments, exhibiting adaptability to high salinity and producing diverse secondary metabolites with valuable properties. However, limited research has focused on their marine diversity, leading to inaccurate species identification. The current study addresses this gap by investigating diverse marine habitats in the Republic of Korea, including sediment, seawater, seaweed, and marine animals. From three coasts of the Korean Peninsula, 472 Aspergillus strains were isolated from the various marine habitats. A total of 41 species were accurately identified using multigenetic markers: internal transcribed spacer, calmodulin, and b-tubulin. The findings underscore the importance of accurate identification and provide a basis for elucidating the functional role of marine-derived Aspergillus species in marine ecosystems.