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Synthesis and Antimicrobial Activity of 1,2,3-Triazoles Containing Quinoline Moiety
V. Sumangala,N. Chidananda,Jennifer Fernandes,N. Suchetha Kumari,Boja Poojary 대한약학회 2010 Archives of Pharmacal Research Vol.33 No.12
A new series of substituted 1,2,3-triazoles (4a-n) were synthesized from 4-azido-2,8-bistrifluoromethylquinoline 2. The 1,3-dipolar cycloaddition reaction of 2 with ethyl acetoacetate afforded 1-(2,8-Bistrifluoromethylquinolin-4-yl)-5-methyl-1,2,3-triazole-4-carboxylic acid 3, which was then converted into its corresponding acid hydrazide 3a. Condensation of this hydrazide with different aromatic aldehydes resulted in the formation of Schiff’s bases, N-[1-Arylmethylene]-1-[2,8-bistrifluoromethylquinoline-4-yl]-5-methyl-1H-1,2,3-triazole-4-carbohydrazides (4a-n). These newly synthesized 1,2,3-triazole derivatives were characterized by analytical and spectral data. All the synthesized compounds were evaluated in vitro for their antibacterial and antifungal activity. A brief investigation of the structure activity relationships revealed that the nature of the substituent on position 4 of the triazole ring influences the antimicrobial activity. Among the newly synthesized compounds, the most active compound was 4n, which contained the 3-methylthien-2-yl moiety and showed a broad spectrum of antimicrobial activity against all the strains used for testing. Compounds 4b, 4c, 4e, 4f, 4h and 4l showed significant antimicrobial activity at the concentration of 6.25 μg/mL.
Darsandhari, Sumangala,Pandey, Ramesh Prasad,Shrestha, Biplav,Parajuli, Prakash,Liou, Kwangkyoung,Sohng, Jae Kyung American Chemical Society 2018 Journal of agricultural and food chemistry Vol.66 No.30
<P>A one-pot multienzyme cofactors recycling (OPME-CR) system was designed for the synthesis of UDP-α-<SMALL>D</SMALL>-galactose, which was combined with LgtB, a β-(1,4) galactosyltransferase from <I>Neisseria meningitidis</I>, to modify various polyphenol glycosides. This system recycles one mole of ADP and one mole of UDP to regenerate one mole of UDP-α-<SMALL>D</SMALL>-galactose by consuming two moles of acetylphosphate and one mole of <SMALL>D</SMALL>-galactose in each cycle. The ATP additionally used to generate UDP from UMP was also recycled at the beginning of the reaction. The engineered cofactors recycling system with LgtB efficiently added a <SMALL>D</SMALL>-galactose unit to a variety of sugar units such as <SMALL>D</SMALL>-glucose, rutinose, and 2-deoxy-<SMALL>D</SMALL>-glucose. The temperature, pH, incubation time, and divalent metal ions for the OPME-CR system were optimized. The maximum number of UDP-α-<SMALL>D</SMALL>-galactose regeneration cycles (RC<SUB>max</SUB>) was 18.24 by fed batch reaction. The engineered system generated natural and non-natural polyphenol saccharides efficiently and cost-effectively.</P> [FIG OMISSION]</BR>
Darsandhari, Sumangala,Dhakal, Dipesh,Shrestha, Biplav,Parajuli, Prakash,Seo, Joo-Hyun,Kim, Tae-Su,Sohng, Jae Kyung Elsevier 2018 Enzyme and microbial technology Vol.113 No.-
<P>A flavonoid comprises polyphenol compounds with pronounced antiviral, antioxidant, anticarcinogenic, and anti-inflammatory effects. The flavonoid modification by methylation provides a greater stability and improved pharrnacokinetic properties. The methyltransferase from plants or microorganisms is responsible for such substrate modifications in a regiospecific or a promiscuous manner. GerMIII, originally characterized as a putative methyltransferase in a dihydrochalcomycin biosynthetic gene cluster of the Streptomyces sp. KCTC 0041BP, was tested for the methylation of the substrates of diverse chemical structures. Among the various tested substrates, flavonoids emerged as the favored substrates for methylation. Further, among the flavonoids, quercetin is the most favorable substrate, followed by luteolin, myricetin, quercetin 3-O-beta-D-glucoside, and fisetin, while only a single product was formed in each case. The products were confirmed by HPLC and mass-spectrometry analyses. A detailed NMR spectrometric analysis of the methylated quercetin and luteolin derivatives confirmed the regiospecific methylation at the 4'-OH position. Modeling and molecular docking provided further insight regarding the most favorable mechanism and substrate architecture for the enzymatic catalysis. Accordingly, a double bond between the C-2 and the C-3 and a single-ring-appended conjugate-hydroxyl group are crucial for the favorable enzymatic conversions of the GerMIII catalysis. Thus, in this study, the enzymatic properties of GerMill and a mechanistic overview of the regiospecific modification that was implemented for the acceptance of quercetin as the most favorable substrate are presented.</P>
Heterologous Production of Clavulanic Acid Intermediates in Streptomyces venezuelae
Biplav Shrestha,디페쉬,Sumangala Darsandhari,라메쉬,Anaya Raj Pokhrel,Hum Nath Jnawali,송재경 한국생물공학회 2017 Biotechnology and Bioprocess Engineering Vol.22 No.4
Heterologous expression can enhance production of diverse secondary metabolites by redirecting precursor pools towards compound of interest. In this study, Streptomyces venezuelae YJ028 was utilized as the heterologous host for the expression of four structural clavulanic acid biosynthesis genes, which encode carboxyethylarginine synthase (ceas2), β-lactam synthetase (bls2), clavaminate synthase (cas2), and proclavaminate amidinohydrolase (pah2). These genes were cloned into pIBR25 expression vector containing ermE* promoter to generate pBS4. The cas2 gene was also cloned into pSET152 to generate pCas2. It was then integrated into the genome of S. venezuelae YJ028. Upon metabolite profiling of recombinant strains by ultra-pressure liquid chromatography-photodiode array (UPLC-PDA) and high resolution liquid chromatography quadruple time-offlight electrospray ionization mass spectrometry (HR-LCQTOF- ESI/MS), the production of following clavulanic acid intermediates in S. venezuelae recombinant were confirmed: deoxygaunidinoproclavaminic acid, guanidinoproclavaminic acid, and dihydroclavaminic acid. This work demonstrates the production of β-lactam intermediates of the clavulanic acid pathway by heterologous expression in S. venezuelae YJ028.
In vitro glycosylation of Compound K using galactosyltrasferase, lgtB from Neisseriameningitidis
Su bin Lim,Sumangala Darsandhari,Jae Kyung Sohng 한국당과학회 2016 한국당과학회 학술대회 Vol.2016 No.07
Compound K (CK) is formed by bio-deglycosylation of major protopanaxadiol (PPD)-type ginsenosides (mainly Rb1, Rb2, Rd and Rc). Although it has never been identified in Panax plants, it is the main functional component detected in mammalian blood or organs after oral administration of ginseng or ginsenosides. It possesses remarkable bioactivities like anti-inflammation, hepatoprotection, antidiabetes and anti-cancer activities. It has even been approved by the China Food and Drug Administration to commence clinical trials for arthritis prevention and treatment. Neisseria β (1,4) galactosyltransferase, LgtB introduces galactose into glucose at its 1 position to form lactose. In the present study, we performed the in vitro enzymatic reaction of CK using UDP-D-galactose as a sugar donor and compound K as an acceptor substrate. Reaction products were analyzed by HPLC and TLC and the product was confirmed by high resolution LC-QTOF-ESI/MS, which revealed the addition of one galactose unit into compound K. This is the first study regarding the addition of galactose to protopanaxadiol type ginsenosides.