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[en] The application of multi-analyte methods for pesticides carrying chromophoric structures by HPLC is described. Details are given on the materials and methods used. Recorded UV spectra of active substances are presented for allowing the verification of purity and the confirmation of substances eluting from the HPLC column. (author)
[en] Bio-pesticides are becoming increasingly important as pest management tools in various cropping systems in the tropics essentially to remedy problems associated with the indiscriminate use of hard and non-environmental friendly inorganic pesticide. In these past few decades, many bio-pesticidal products, both microbial-based (bacteria, fungi, microsprodia, entomopathogenic nematodes and viruses) and plant-based botanicals (rotenone and azadiracthin) have been studied for their use against insect pests in the tropics. In this study, the effects of the concentration process with respect to the yield of rotenone (mg) and its concentration (mg/mL) are presented extensively. The raw plants were collected from Kota Johor Lama, Johor and sorted to obtain the roots and stems. Only the roots and stems were utilized as raw materials of the extraction process. The rotenone from roots and stems was extracted using the normal soaking extraction (NSE) at 28 to 30 degree Celsius with 95 % (v/v) of acetone as a solvent and the solvent-to-solid ratio of 10 mL/ g. The extraction was carried out for 24 h. Next, the liquid crude extract was concentrated using the rotary evaporator at 50 degree Celsius and 80 mbar of vacuum pressure to remove approximately 90 % of solvent. The fractions of the liquid crude extract were collected (15 min/ mL/ fraction), diluted (1/100 with acetone) and cleaned up (to remove any fine debris) prior to determination of rotenone content (mg) and concentration (mg/mL) by using the reverse-phase high performance liquid chromatography (RP-HPLC). Finally, the results showed that there was a significant effect of thermal degradation or dissipation of rotenone content at higher operating temperature (greater than 40 degree Celsius) with a rapid rotenone reduction for the first 15 min of exposure. The possibilities for better exploitation and identification of the effective operating parameters based on the above mentioned results will be perhaps discussed in the future. (author)
[en] Multi-wavelength fingerprints of Cassia seed, a traditional Chinese medicine (TCM), were collected by high-performance liquid chromatography (HPLC) at two wavelengths with the use of diode array detection. The two data sets of chromatograms were combined by the data fusion-based method. This data set of fingerprints was compared separately with the two data sets collected at each of the two wavelengths. It was demonstrated with the use of principal component analysis (PCA), that multi-wavelength fingerprints provided a much improved representation of the differences in the samples. Thereafter, the multi-wavelength fingerprint data set was submitted for classification to a suite of chemometrics methods viz. fuzzy clustering (FC), SIMCA and the rank ordering MCDM PROMETHEE and GAIA. Each method highlighted different properties of the data matrix according to the fingerprints from different types of Cassia seeds. In general, the PROMETHEE and GAIA MCDM methods provided the most comprehensive information for matching and discrimination of the fingerprints, and appeared to be best suited for quality assurance purposes for these and similar types of sample.
[en] In order to investigate potential therapeutically agents, novel products of Biginelli reaction (4a-l) were synthesized and exposed to cytotoxic and caspase activities, angiogenesis, cell cycle distribution, gene and microRNA expression levels, lipophilicity assessment and docking study. Among the twelve novel compounds (4a-l) evaluated for the cytotoxic activity, five of them (4c, 4d, 4f, 4k and 4l) that showed excellent activity on the tested cell lines (HeLa, LS174 and A549) were selected for further evaluation. Interestingly, compound 4f has up to three times higher selectivity index (SI) towards cancer cells than cisplatin (on HeLa, LS174 and A549 SI = 18.2, 13.5 and 11.2, respectively). The obtained results from cell cycle distribution and caspase activity indicate that tested compounds (4c, 4d, 4f, 4k and 4l) promoted caspase-9 activation, implicated in the intrinsic pathway of apoptosis. Lipophilicity of 4a-l was determinate by using reversed-phase high-performance liquid chromatography. © 2019 Elsevier Inc.
[en] Hibiscus rosa-sinensis or commonly known as 'Hibiscus' is a kind of decorative flowers which often grown in a subtropical countries. This plant is often used in the preparation of traditional medicine because of its pharmacological properties that are capable of treating number of health problems. The plant contains several essential bio-active substances and nutrients especially in its flowers and leaves. One of the bioactive substances is β-sitosterol which is abundant in the leaf crude extract. Hibiscus leaves water extract yielded mucilage which is widely used in lowering high body temperature due to fever (antipyretic). Therefore, the main objective of this paper was to determine the maximum concentration of mucilage and time of exhaustive extraction from fresh and dried leaves using a Peleq's mathematical model. Moreover, several analyses were conducted such as qualitative analysis to determine the presence of bioactive substances using high performance liquid chromatography (HPLC) and determination of functional groups by means of fourier transform infrared method (FTIR). Physical properties of the extracts were evaluated to determine its acidity and viscosity of the mucilage with respect to different shear stress. The result show that the extract of dried Hibiscus leaves exhibited high in its concentrations even though the achieved exhaustive extraction was relatively slow as compared to fresh leaves (p < 0.05). Based on the HPLC analysis, the main bio-active substances of β-sitosterol was only existed in fresh leaves samples. The absence of β-sitosterol in dried leaves extract was caused by the loss of other important bio-active substances which possess surfactant capability, due to thermal degradation of drying process or the component itself was deteriorated during the pre-preparation drying process. Furthermore, the FTIR analysis shows that the same composition of the absorption peaks for both extracts with the highest absorption of O-H bonds was observed. This proves that the content of β-sitosterol in both extracts was too small and the composition of other phytosterols was observed to dominate and influence the availability of β-sitosterol in the crude extract. Meanwhile, physical properties analysis of the both extracts was carried to show the effect of drying process on the observed bio-active components. The high acidity of the fresh leaf extract was attributed to the presence of all bio-active ingredients. Meanwhile for the dried leaf extract, a close neutral pH value was observed due to the bio-active decomposition which is acidic in nature and sensitive to heat. (author)
[en] A valid method was developed to assess 2 mg Clonazepam tablets disolution without lactose by high-performance liquid chromatography by UV detection to 254 nm. Establishment of Clonazepam in dissolution medium was confirmed, and parameters of specificity, linearity, and accuracy were assessed, as well as influence of filtration and stability or active principle. Linearity curve was drawed in rank of 1, 2-2,6 μg/mL, with a correlation coefficient similar to 0,99418; statistical test wasn't statistically significant for interceptor and slope. In study, it was possible to demonstrate that stability or active principle in dissolution was maintained in more than double of duration of dissolution assay. (Author)
[en] The octanol/ water partition coefficient (P_o_w) and water solubility (S_w) are important physico-chemical properties for an environmental risk assessment of a chemical substance, as well as ecotoxicity. It can be an indication of the extent to which the chemical might bioaccumulate in aquatic organisms. The log P_o_w of palm-based fatty acids was estimated using high performance liquid chromatography (HPLC) method, while the S_w value was determined using linear correlation between S_w and log P_o_w of reference compounds. The ecotoxicity of palm-based fatty acids was measured using test method OECD 203, Fish Acute Toxicity with common carp (Cyprinos carpio) as the test species. The short-chained C6 to C10 palm fatty acids were chosen for this study because they are generally toxic and can cause irritation to human and may have an adverse effect towards aquatic organisms. The log P_o_w values showed that both C6 and C8 fatty acids had low affinity towards aquatic organisms, but C10 fatty acid showed medium affinity towards these organisms. As for water solubility, C6 fatty acid had high affinity towards water, while both C8 and C10 fatty acids showed medium affinity towards water. The LC_5_0 value of C6, C8 and C10 palm FAs are 7 mg litre"-"1, 7 mg litre"-"1 and 20 mg litre"-"1, respectively. It can be concluded that, the higher the carbon chain number of the fatty acid, the higher is the partition coefficient value, the water solubility decreases. The palm-based fatty acid can be considered as moderately toxic to aquatic organisms. These data can be used by the palm-based oleochemical manufacturers for product registration, preparation of product dossier or for marketing purposes. (author)
[en] Authors developed a stability study of 50 mg Propylthiouracil tablets and determination of its expiry date. This study was conducted by fixed life methods and of accelerated stability by high-performance liquid chromatography, validated in Drugs Research and Development Center. Fixed life study was conducted during 24 months at room temperature; whereas the accelerated stability study was conducted exposing the product to light influence, humidity and temperature; during 3 months a analysis was performed for the two first ones and over 6 months in the case of temperature study. Propylthiouracil formula (50 mg tablets) fulfilled the quality specifications described in Pharmacopeia. Results of stability study by fixed life after 24 months showed that thr product maintain the parameter determining its quality during this period, and in the accelerated studies there was not a significant degradation of product. Two years was the expity date established in above mentioned conditions
[en] A rapid method for quantification of vitamin E isomers (α-, β-, γ-, δ- tocopherol and tocotrienol) was developed by using ultra performance liquid chromatography (UPLC) from human plasma. This method involved liquid-liquid extraction of plasma sample to extract the lipophilic portion for injection into UPLC system. The UPLC system was equipped with fluorescent detector (296 nm excitation, 330 nm emissions) and C18 column with 1.7 μm particle size (2.1 x 110 mm column) for particle separation. The mobile phase comprises of 1.0 % of H2O and 99.0 % of methanol (HPLC grade) with flow rate adjusted at 0.4 ml min-1. Peak separations were accomplished after 3.50 minutes and 5 μl treated samples were required for injection. Results obtained showed that the UPLC system was able to separate, detect and quantitate six peaks, namely α-, γ-, δ- tocopherol and tocotrienol, respectively. However, it failed to separate and quantification both, β- tocopherol and tocotrienol due to low amount in nature. The calibration curve was linear for a concentration ranging from 1 μg ml-1 - 10 μg ml-1 of total vitamin E standard which r2 > 0.9996 for all isomers. The within day and between day coefficients of variation were less than 10.29 % (n=4) and 10.73 % (n=4) for all isomers. The accuracy of isomers quantification for 1 μg ml-1 (n=4) and 10 μg/ ml (n=4) vitamin E stocks were 93.52 % - 98.13 %. The within day and between day coefficients of variation for vitamin E standard were less than 7.59 % (n=4) and 9.74 % (n=4) for all isomers while for plasma sample were less than 10.29 % (n=4) and 10.73 % (n=4) for all isomers. The recovery rates for all isomer were ranging from 98.96 ± 7.22 and 107.50 ± 1.19 and the limit of detection was 2.53 ng. The present data suggested that this method required extremely short analysis time for example 2.50 min, required less samples for injection and excellent chromatographic reproducibility. (author)
[en] This chromatographic study deals with the development of a convenient and versatile method to separate Room Temperature Ionic Liquids. Different modes of chromatography were studied. The study attempts to answer the following question: 'what were the most important interactions for the separation of ionic liquids?'. The results show that the essential interactions to assure a good retention of RTILs are the ionic ones and that hydrophobic interactions play a role in the selectivity of the separation. The separation of five imidazolium salt with a traditional dial columns in Hydrophilic Interaction Chromatography (HILIC) was demonstrated. It shows that neutral diol grafted column allows an important retention that we assume is due to the capability of diol to develop a thick layer of water. Furthermore, stationary phase based on mixed interaction associating ion exchange and hydrophobic properties were studied. Firstly, it will be argued that it is possible to separate RTILs with a convenient retention and resolution according to a reverse phase elution with the Primesep columns made of a brush type long alkyl chain with an embedded negatively charged functional group. Secondly, a successful separation of RTILs in HILIC mode with a mixed phase column containing a cationic exchanger and a hydrophobic octyl chain length will be demonstrated. (author)