Biotransformation of Sesquiterpenoids, Ionones, Damascones, Adamantanes, and Aromatic Compounds by Green Algae, Fungi, and Mammals
K. Hüsnü Can Başer, Gerhard Buchbauer in Handbook of Essential Oils, 2020
(+)-Valencene (1) (20 mg/50 mL) isolated from the essential oil of Valencia orange was added to the medium and biotransformed by Chlorella fusca for a further 18 days to afford nootkatone (2) (gas chromatography–mass spectrometry [GC-MS] peak area, 89%; isolated yield, 63%) (Figure 23.2) (Noma et al., 2001b; Furusawa et al., 2005a,b). The reduction of 2 with NaBH4 and CeCl3 gave 2α-hydroxyvalencene (3) in 87% yield, followed by Mitsunobu reaction with p-nitrobenzoic acid, triphenylphosphine, and diethyl azodicarboxylate to give nootkatol (2β-hydroxyvalencene) (4)—possessing calcium antagonistic activity—isolated from Alpinia oxyphylla (Shoji et al., 1984) in 42% yield. Compounds 3 and 4 thus obtained were easily biotransformed by C. fusca and Chlorella pyrenoidosa for only 1 day to give nootkatone (2) in good yield (80%–90%), respectively. The biotransformation of compound 1 was further carried out by C. pyrenoidosa and Chlorella vulgaris (Furusawa et al., 2005a,b) and soil bacteria (Noma et al., 2001a) to give nootkatone in good yield (Table 23.1).
Affinity Modification — Organic Chemistry
Dmitri G. Knorre, Valentin V. Vlassov in Affinity Modification of Biopolymers, 1989
At the same time, 5′-terminal phosphomonoester group and 3′-terminal cis-diol group of RNAs, ribonucleotides, and oligodeoxyribonucleotides with a 3′-terminal ribonucleotide fragment are widely used for the preparation of reactive derivatives. Thus, oligonucleotides with an activated 5′-terminal phosphate were already described in Section II.B. Alkylating derivatives of oligonucleotides CXXV are easily obtained by the treatment of oligonucleotides with p-(N-2-chloroethyl-N-methylamino)benzylamine in the presence of triphenylphosphine and dipyridyldisulfide.257
Toxic Effects and Biodistribution of Ultrasmall Gold Nanoparticles *
Valerio Voliani in Nanomaterials and Neoplasms, 2021
In accordance with the previous findings, for the 1.4 nm AuNP IC50 values ranging from 30 to 46 µM were obtained. Hence, this is the most toxic particle, as the IC50 values of the particles with 0.8 nm (Au9 cluster) [31], 1.2 and 1.8 nm were 250, 140, and 230 µM, respectively. These experiments also included reference measurements on pure ligands, as well as on a 1.4 nm sized AuNP with sodium 3,3′,3″-triphenylphosphine sulfonate (TPPTS) as ligand, which is the threefold sulfonated derivative of tri-phenylphosphine, thus being higher negatively charged, as compared to the monosulfonated TPPMS. These particles (labeled as Au1.4TPPTS in Fig. 15.16) showed similar IC50 values as Au1.4MS. In contrast, the 15 nm AuNPs were found to be non-toxic even at concentrations above 6300 µM than the smaller particles, indicating a clear trend of decreasing cytotoxicity with increasing particle size. Another interesting outcome of this study was that also the cellular response is size dependent, in that 1.4-nm particles cause predominantly rapid cell death by necrosis within 12 h, while closely related AuNP with 1.2 nm in diameter affects predominantly programmed cell death by apoptosis. These data were complemented in a very recent study, which analyzed the cytotoxicity of AuNP in the size range between 1.4 and 15 nm, and thus fill the size gap between these two cornerstones of the highest and lowest cytotoxicity [10]. Besides Au1.4MS, AuNPs with 4.7, 10, 12, and 15 nm, all stabilized with either TPPMS or TPPTS, respectively, were tested regarding their cytotoxicity towards HeLa cells. Again, Au1.4MS was found to be the most cytotoxic species (IC50 value of 43 µM), while all other particles showed decreasing toxicity with increasing size up to 15 nm, which corroborates the clear trend of size-dependent cytotoxicity. Furthermore, these studies disclosed that all TPPTS-stabilized AuNPs were found to be less toxic than TPPMS-stabilized ones.
The improved antiviral activities of amino-modified chitosan derivatives on Newcastle virus
Published in Drug and Chemical Toxicology, 2021
Xiaofei He, Ronge Xing, Song Liu, Yukun Qin, Kecheng Li, Huahua Yu, Pengcheng Li
Chitosan (3 g) was dissolved in 60 mL dimethylformamide (DMF) (5% water), and then phthalic anhydride (PA) (8 g) was added and reacted at 120 °C for 8 h to synthesize N-phthaloyl chitosan (NPC) (Li et al. 2012, Meng et al. 2012). For the next step, the NPC (3.4 g) was dissolved in 337 mL N-methyl-2-pyrrolidone (NMP), and then added 20.5 g N-bromosuccinimide (NBS) and 30.3 g triphenylphosphine (PPh3). The substitution reaction was implemented at 80 °C for 2 h to get 6-deoxy-6-bromo-N-phthaloyl chitosan (6BrNPC). 6BrNPC (1 g) was introduced in 26 mL ethylenediamine (EDA) and reacted at 80 °C for 24 h for 6-aminoethylamino-6-deoxy-N-phthaloyl chitosan (6ANPC). Eventually, 6ANPC (0.5 g) was introduced in 25 mL N-methyl-2-pyrrolidone (NMP) and 25 mL hydrazine hydrate (HAH) (80%) to react at 100 °C for 4 h to get 6-aminoethylamino-6-deoxy chitosan (6AC).
Discovery of orally active chalcones as histone lysine specific demethylase 1 inhibitors for the treatment of leukaemia
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2021
Yang Li, Ying Sun, Yang Zhou, Xinyang Li, Huan Zhang, Guojun Zhang
Chalcone derivatives B were prepared by a condensation reaction from 1–(4-azidophenyl)ethan-1-one A and different benzaldehydes without purification. To a solution of triphenylphosphine (1 mmol), chalcone intermediates B (2 mmol), and tetrahydrofuran (12 ml) was added water (3 ml), the mixture was stirred for 4 h. Upon the completion, ethyl acetate and water were added. The organic layers were washed with water for several times to remove the tetrahydrofuran, and then evaporated to give the crude products. The crude product (1 mmol), chloroacetyl chloride (1.2 mmol), and triethylamine (0.5 mmol) were dissolved in acetone (10 ml) to stir for 8 h at room temperature. Upon completion, the system was purified with column chromatography (hexane: ethyl acetate = 9:1) to obtain analogues C1∼C4. Compound C4 was a reported chalcone intermediate from the previous reference [19].
Gemcitabine cationic polymeric nanoparticles against ovarian cancer: formulation, characterization, and targeted drug delivery
Published in Drug Delivery, 2022
Sankha Bhattacharya, Md Meraj Anjum, Krishna Kumar Patel
To load GTB into bio-adhesive chitosan nanoparticles, the ionotropic gelation technique was implemented (Sacco et al., 2021). To obtain a blank polymeric nanoparticle, 0.7 mg/mL triphenylphosphine (TPP) solution has been added to 2.25 mg/mL of chitosan aqueous solution maintaining the temperature at 25 °C. The presence of TPP, which has a phosphorus center and is an active Lewis's base, could keep the reaction temperature stable. Nevertheless, TPP has sp3 hybridization at the phosphorous center; this molecule can able to donate another molecule, and hence, the coupling is believed to happen between the positive amino group of chitosan and negative TPP; which ultimately leads to prepare nanoparticles. To prepare GTB-loaded chitosan nanoparticles, GTB was dissolved into TPP solution, which was preloaded with 30% of chitosan (CS) solution. The protocol for preparing blank nanoparticles was subsequently followed. The prepared nanoparticles were washed three times at 15,000 rpm for 45 min with centrifugation. The nanoparticle pallets formed in the centrifuge tube bottom were further dispersed into distilled water and filtered with a membrane filter of 0.45 μm.
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