Electrochemistry

Publication Title: 
Phytochemistry

Four aqueous extracts from different parts of medicinal plants used in Ayurveda (an ancient Indian Medicine) viz., Momardica charantia Linn (AP1), Glycyrrhiza glabra (AP2), Acacia catechu (AP3), and Terminalia chebula (AP4) were examined for their potential as antioxidants. The antioxidant activity of these extracts was tested by studying the inhibition of radiation induced lipid peroxidation in rat liver microsomes at different doses in the range of 100-600 Gy as estimated by thiobarbituric acid reactive substances (TBARS).

Author(s): 
Naik, G. H.
Priyadarsini, K. I.
Satav, J. G.
Banavalikar, M. M.
Sohoni, D. P.
Biyani, M. K.
Mohan, H.
Publication Title: 
Antimicrobial Agents and Chemotherapy

Six patients with uncomplicated falciparum malaria received artesunate for 5 days. Plasma concentrations of artesunate and dihydroartemisinin were determined by high-performance liquid chromatography with electrochemical detection. The concentrations of dihydroartemisinin in plasma 2 h after a dose showed a time-dependent decline. Concentrations of artesunate in plasma especially after the last dose, were very low. Despite this, all patients responded with a fast recovery.

Author(s): 
Khanh, N. X.
de Vries, P. J.
Ha, L. D.
van Boxtel, C. J.
Koopmans, R.
Kager, P. A.
Publication Title: 
Antimicrobial Agents and Chemotherapy

The pharmacokinetic properties of oral and intravenous artesunate (2 mg/kg of body weight) were studied in 19 adult patients with acute uncomplicated Plasmodium falciparum malaria by using a randomized crossover design. A sensitive bioassay was used to measure the antimalarial activity in plasma which results from artesunate and its principal metabolite, dihydroartemisinin. The oral study was repeated with 15 patients during convalescence. The mean absolute oral bioavailability of the antimalarial agent in patients with acute malaria was 61% (95% confidence interval [CI], 52 to 70%).

Author(s): 
Newton, P.
Suputtamongkol, Y.
Teja-Isavadharm, P.
Pukrittayakamee, S.
Navaratnam, V.
Bates, I.
White, N.
Publication Title: 
Antimicrobial Agents and Chemotherapy

Artemisinin and its derivatives, artesunate and artemether, are rapidly acting antimalarials that are used for the treatment of severe and uncomplicated multidrug-resistant falciparum malaria. To optimize treatment regimens that use this new class of antimalarials, there is a need for readily available and reproducible assays to monitor drug levels closely in patients. A sensitive and reproducible bioassay for the measurement of the concentrations of artemisinin derivatives in plasma and serum is described.

Author(s): 
Teja-Isavadharm, Paktiya
Peggins, James O.
Brewer, Thomas G.
White, Nicholas J.
Webster, H. Kyle
Kyle, Dennis E.
Publication Title: 
Antimicrobial Agents and Chemotherapy

A simple, nonisotopic, semiautomated bioassay for the measurement of antimalarial drug levels in plasma or serum based on the quantitation of histidine-rich protein II in malaria culture is presented. The assay requires only small sample volumes and was found to be highly sensitive and reproducible. The results closely paralleled those obtained with isotopic bioassays (R = 0.988, P < 0.001) and high-performance liquid chromatography-electrochemical detection (R = 0.978, P < 0.001).

Author(s): 
Noedl, Harald
Teja-Isavadharm, Paktiya
Miller, Robert Scott
Publication Title: 
Analytical Sciences: The International Journal of the Japan Society for Analytical Chemistry

A wax-impregnated carbon paste electrode with mercury oxalate as the bulk modifier is found to be suitable for the determination of heavy metal ions by differential pulse anodic stripping voltammetry. The contents of binder and modifier have been optimized, until they showed low background current and easy renewability. The bulk-modified electrode is applied for the simultaneous determination of Zn, Cd, Pb and Cu in medicinal plants and Ayurvedic tablets (Liv 52). The results obtained have been validated with HMDE and AAS and are found to be comparable.

Author(s): 
Mascarenhas, Ronald J.
Satpati, Ashis K.
Yellappa, Shivaraj
Sherigara, Bailure S.
Bopiah, Ajjikuttira K.
Publication Title: 
Phytochemistry

Four aqueous extracts from different parts of medicinal plants used in Ayurveda (an ancient Indian Medicine) viz., Momardica charantia Linn (AP1), Glycyrrhiza glabra (AP2), Acacia catechu (AP3), and Terminalia chebula (AP4) were examined for their potential as antioxidants. The antioxidant activity of these extracts was tested by studying the inhibition of radiation induced lipid peroxidation in rat liver microsomes at different doses in the range of 100-600 Gy as estimated by thiobarbituric acid reactive substances (TBARS).

Author(s): 
Naik, G. H.
Priyadarsini, K. I.
Satav, J. G.
Banavalikar, M. M.
Sohoni, D. P.
Biyani, M. K.
Mohan, H.
Publication Title: 
Analytical Sciences: The International Journal of the Japan Society for Analytical Chemistry

A wax-impregnated carbon paste electrode with mercury oxalate as the bulk modifier is found to be suitable for the determination of heavy metal ions by differential pulse anodic stripping voltammetry. The contents of binder and modifier have been optimized, until they showed low background current and easy renewability. The bulk-modified electrode is applied for the simultaneous determination of Zn, Cd, Pb and Cu in medicinal plants and Ayurvedic tablets (Liv 52). The results obtained have been validated with HMDE and AAS and are found to be comparable.

Author(s): 
Mascarenhas, Ronald J.
Satpati, Ashis K.
Yellappa, Shivaraj
Sherigara, Bailure S.
Bopiah, Ajjikuttira K.
Publication Title: 
Analytical Sciences: The International Journal of the Japan Society for Analytical Chemistry

Capillary electrophoresis with electrochemical detection has been employed for the separation and determination of the three active constituents (paeonol, benzoyloxypaeoniflorin, and oxypaeoniflorin) in traditional Chinese medicine, Moutan Cortex (root cortex of Paeonia suffruticosa Andrews). The effects of several important factors, such as the concentration of running buffer, the separation voltage, the injection time, and the detection potential, were investigated to determine the optimum conditions.

Author(s): 
Chen, Gang
Zhang, Luyan
Yang, Pengyuan
Publication Title: 
Biosensors & Bioelectronics

An albumin biosensor based on a potentiometric measurement using Biofield-effect-transistor (BioFET) has been designed and fabricated, and its characteristics were investigated. The BioFET was fabricated using semiconductor integrated circuit (IC) technology. The gate surface of the BioFET was chemically modified by newly developed self-assembled monolayer (SAM) synthesized by a thiazole benzo crown ether ethylamine (TBCEA)-thioctic acid to immobilize anti-albumin. SAM formation, antibody immobilization, and antigen-antibody interaction were verified using surface plasmon resonance (SPR).

Author(s): 
Park, Keun-Yong
Sohn, Young-Soo
Kim, Chang-Kyu
Kim, Hong-Seok
Bae, Young-Seuk
Choi, Sie-Young
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