• Natural Product Sciences
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• 제13권3호
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• pp.180-185
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• 2007

Dichrostachys cinerea (Linn.) is commonly known as Vadatalla and used as phytotherapeutic agent. Tender shoots of the plant bruised and applied to the eyes in case of ophthalmia. The root is astringent and used in rheumatism, urinary calculi and renal troubles. The effect of the Ethanolic and aqueous extract of the root of D. cinerea were studied for its anti-urolithiatic and diuretic activity at 200 mg/kg dose level in male Wistar albino rats. Ethylene glycol feeding resulted in hyperoxaluria as well as increased renal excretion of calcium and phosphate. Supplementation with aqueous and ethanolic extract of the plant significantly reduced the elevated urinary oxalate, showing a regulatory action on endogenous oxalate synthesis. Compared to ethanolic extract, aqueous extract exhibited significant anti-urolithiatic activity. Both the extracts showed significant diuretic activity. The results of our present study supports folklore claim of D. cinerea.

• Natural Product Sciences
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• 제4권2호
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• pp.78-83
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• 1998

Chemical investigation on a sample of the needles of Himalayan Taxus baccata has resulted in the isolation of several taxoids including taxol (1) 10-deacetyl-baccatin III (2) and 2-deacetoxytaxinine J (3) along with different lignans (6 and 7) and simple phenolics (8, 9, 10, 11 and 12). The occurrence of 4-(4'-hydroxyphenyl)-butane-2-one and 4-(4'-hydroxyphenyl)-trans-but 3-ene-2-one (8) in Taxus species is reported for the first time. The $^{13}C-NMR$ spectral data of two rearranged taxiod constituents, brevifoliol (4) and 13-decinnamoyltaxchinin B (5) are presented. The acid-catalyzed decomposition of taxol has been discussed. The synthesis of other two constituents, rhododendrol (10) and hibalactone (7) has been described.

• Natural Product Sciences
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• 제28권3호
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• pp.93-104
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• 2022

Methicillin-resistant Staphylococcus aureus (MRSA) is a serious threat to the global healthcare system. Ineffective and resistance to antibiotic treatments have increased morbidity and mortality rates worldwide. New and effective antibiotics are needed to combat against bacterial resistance. Endophytic fungi are crucial reservoirs of novel bioactive metabolites. In particular, the secondary metabolites show promising therapeutic potential, notably, antibacterial. This review discussed the emerging potential of endophytic fungi as anti-MRSA agents. The ecological sources of endophytic fungi were discussed with the synthesis of bioactive metabolites. The mode of antibacterial actions was elucidated to give a better understanding of the mechanisms involved. This review may serve as an important reference for future discovery and developments of anti-MRSA agents from endophytic fungi.

• Natural Product Sciences
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• 제5권2호
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• pp.93-96
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• 1999

A new ergosteryl myristate (1) and ergosterol (2) have been isolated from the organic extract of the mycelium of unidentified marine algicolous fungus, isolate MF001. The structure of a new compound was assigned on the basis of comprehensive spectroscopic analyses and chemical synthesis.

• Parasites, Hosts and Diseases
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• 제43권3호
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• pp.123-126
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• 2005

Each diastereomer of 10-thiophenyl- and 10-benzenesulfonyl-dihydroartemisinin was synthesized from artemisinin in three steps, and screened against chloroquine-resistance and chloroquine-sensitive Plasmodium falciparum. Three of the four tested compounds were found to be effective. Especially, 10$\beta$-benzenesulfonyl-dihy-droartemisinin showed stronger antimalarial activity than artemisinin.

• 한국세라믹학회지
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• 제53권1호
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• pp.7-12
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• 2016

In this paper, we have developed a simple, new and economical carbonation method to synthesize a pure form of aragonite needles using dolomite raw materials. The obtained aragonite Precipitated Calcium Carbonate (PCC) was characterized by XRD and SEM, for the measurement of morphology, particle size, and aspect ratio (ratio of length to diameter of the particles). The synthesis of aragonite PCC involves two steps. At first, after calcinated dolomite fine powder was dissolved in water for hydration, the hydrated solution was mixed with aqueous solution of magnesium chloride at $80^{\circ}C$, and then $CO_2$ was bubbled into the suspension for 3 h to produce aragonite PCC. Finally, aragonite type precipitated calcium carbonate can be synthesized from natural dolomite via a simple carbonation process, yielding product with average particle size of $30-40{\mu}m$.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.253.2-253.2
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• 2002

Apicidin. a natural product HDAC inhibitor. is recently isolated from Fusarium sp. at Merk Research Laboratories, induces therapeutic applications as a broad spectrum antiprotozoal agent to muti-drug resistant malaria and a potential antitumor agent. The biological activity of apicidin appears to be apicocomplexan HDAC at low nanomolar concentrations. (omitted)

• Natural Product Sciences
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• 제4권3호
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• pp.136-142
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• 1998

Atratoxin $B_1$ which was found to inhibit the growth of Candida albicans caused structural and morphological alteration of the cells. Increased accumulation of vesicles and membranous bodies in the cytoplasm, and alterations of the cell membrane and cell wall were most obvious. Sequential lytic events of the cells eventually resulted in complete disintegration of the cytoplasmic structures. These results suggested that atratoxin $B_1$ functioned by either blocking the biosynthetic step during cell wall synthesis, altering cell wall metabolism or dissolution of the cell organelles. These changes caused a progressive destruction of the cell wall leading to cell lysis.

• Journal of Microbiology and Biotechnology
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• 제14권6호
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• pp.1280-1285
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• 2004

Retron is a prokaryotic genetic element, producing a short single-stranded DNA covalently linked to RNA (msDNA-RNA) by a reverse transcriptase (RT). In retron EC83, msDNA is further processed at between the 4th and the $5^{th}$ nucleotides, leaving a 79 nucleotide-long single-stranded DNA as a final product. To investigate this site-specific cleavage in msDNA synthesis, we purified the RT protein of retron EC83. Initially, RT ORF was cloned under the tac promoter, but the expression was very poor largely because of poor translation. In order to facilitate translation, the nucleotide sequence for the first nine amino acids was randomized with synonymous codons. This change of downstream sequence of translational initiation codon greatly affected the efficiency of translation. We could isolate clones which greatly increased RT production, and their sequences were compared to those of the low producers. The overproduced protein was purified and was shown to have RT activity.

• Bulletin of the Korean Chemical Society
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• 제9권6호
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• pp.379-381
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• 1988

Racemic nuciferal(1) and nuciferol(2), the terpenic natural perfumeries, have been synthesized by a simple procedure. The benzylic halide 6; 1-(1-chloroethyl)-4-methylbenzene, was prepared by converting p-tolualdehyde(4) into 1-(p-tolyl)-1-ethanol(5), followed by convertion of 5 into corresponding chloride. The Grignard reagent of 6 was reacted with the bromoacetal 7, 2-(2-bromoethyl)-1,3-dioxolane, to give a crosscoupling product 8, which was hydrolysed to 4-(p-tolyl)-pentanal (9). The Wittig reaction of isopropylide 10 with 9 yielded arcurcumen(11). The stereospecific allylic oxidation of the gem-dimethyl olefin 11 with selenium dioxide afforded a trans-aldehyde, (${\pm}$)-1, which was reduced to corresponding alcohol, (${\pm}$)-2.