Enzymatic Synthesis of 3-O-Acylbetulinic Acid Derivatives and Prediction of Acylation Using Response Surface Methodology and Artificial Neural Network Analyses

In this study, 3-O-acyl-betulinic acid derivatives were synthesized by the reaction of betulinic acid with various anhydrides using lipase as a biocatalyst in organic solvents. The reaction between betulinic acid and phthalic anhydride was chosen as the model reaction for optimization studies. The immobilized lipase from Candida antarctica (Novozym 435) was selected as a biocatalyst. The effects of different reaction parameters were investigated and optimized in the model reaction using one-variable-ata- time technique for the first time. Optimum conditions to produce 3-O-phthalylbetulinic acid up to 61.8% were observed at a reaction time of 24 hours; amount of enzyme, 176 mg; betulinic acid to phthalic anhydride molar ratio of 1:1; amount of celite, 170 mg and 6 mg of K2CO3 in a mixture of n-hexane-chloroform (1:1, v/v) as organic solvent at 55'C. The response surface methodology (RSM), based on a five-level, four-variable central composite rotatable design (CCRD), was employed to evaluate the effects of synthesis parameters of the model reaction. Using the RSM analysis, it was observed that the maximum yield of 3-O-phthalyl-betulinic acid (65.8%) could be obtained using 145.6 mg of enzyme, reaction temperature of 53.9°C, reaction time of 20.3 hours and betulinic acid to phthalic anhydride molar ratio of 1:1.11. The actual experimental value obtained was at 64.7%. Artificial neural network (ANN) was successfully developed to model and predict the enzymatic synthesis of 3-O-phthalyl-betulinic acid. The network consists of an input layer, a hidden layer and an output layer. Inputs for the network were reaction time, reaction temperature, enzyme amount and substrate molar ratio, while the output was percentage isolated yield of ester. Four different training algorithms, belonging to two classes, namely gradient descent and Levenberg-Marquardt, were used to train ANN. The best results were obtained from the quick propagation algorithm (QP) with 4-9-1 topology. Based on the ANN analysis, the optimal conditions to obtain the highest yield were 148.3 mg enzyme, reaction temperature of 53.1°C, reaction time of 20.3 hours and betulinic acid to phthalic anhydride molar ratio of 1:1.24. The predicted and actual yields were 64.9 and 64.3%, respectively. In this work, the ANN and RSM analysis were investigated on the enzymatic synthesis of 3-O-phthalyl-betulinic acid for the first time. Finally, several betulinic acid esters (compounds 57-66) were synthesized using the optimal operation conditions which were obtained by the RSM technique. Esterification of betulinic acid with various anhydrides was performed at 54ºC in a mixture of n-hexane- chloroform (1:1, v/v) for 20.3 hours, catalyzed by Novozym 435, gave 24.7 to 79.3% yield. Five new compounds (58, 62, 64, 65 and 66) were synthesized for the first time in the present study. In brief, the anti-cancer activity of betulinic acid (1) and its 3-O-acylated derivatives (compounds 57-66) were evaluated against human lung carcinoma (A549) and human ovarian (CAOV3) cancer cell lines. In particular, compounds (59), (61) and (63) were found to show IC50 < 10 μg/ml against A549 cancer cell line tested and showed better cytotoxicity than betulinic acid. In the ovarian cancer cell line, all betulinic acid derivatives prepared revealed weaker cytotoxicity than betulinic acid

Do pre-adenotonsillectomy echocardiographic findings change postoperatively in children with severe adenotonsillar hypertrophy

AbstractPurposeHypertrophy of adenotonsillar tissue is one of the most common problems in childhood age and causes upper airway obstruction and even obstructive sleep apnea symptoms in severe forms. The aim of this study is to evaluate the changes of pre-adentonsillectomy echocardiographic findings after operation.Material and methodsFrom August 2007 to November 2008, 55 children with adenotonsillar hypertrophy and obstructive-sleep symptoms (aged 3–11years old of which 35 were males and 20 females) were randomly selected. Preoperatively echocardiography was performed for all patients by the pediatric cardiologist.In control group 55 children who referred to otolaryngology clinic because of non adenotonsillar related disease evaluated. One month and six months after operation, patients with positive findings were followed up and again echocardiography was performed separately.ResultsNo complaints of apnea were reported. Tonsillar grades of all cases were type III or IV. The preoperative mean pulmonary arterial pressure levels of the 4 (7.3%) children were higher than normal range (25mmHg) and it decreased significantly after operation (P<0.000) (Preoperative MPAP=32±3mmHg, and six months postoperative follow up, MPAP=11±5mmHg). All the patients’ parents complained about severe open mouth snoring, agitated sleep and hyperpnoea of their children.The preoperative tricuspid regurgitation pressure level of 7 children was higher than normal range and it decreased significantly after operation (P<0.000 preoperative TR=34±8mmHg postoperative TR=19±6mmHg). AC/ET in these seven patients were lower than 0.4. In control group echocardiography findings are normal.ConclusionSevere chronic hypertrophic adenotonsillar tissue caused higher tricuspid regurgitation pressure and mean pulmonary arterial pressure

Spectroscopic data of 3-O-acetyl-betulinic acid: an antitumor reagent

In this paper, the spectroscopic data of the 3-O-acetyl betulinic acid is reported. This compound was prepared by enzymatic reaction of betulinic acid and acetic anhydride in the presence of lipase from Candida antarctica (Novozem® 435) at 54oC for 20 h in 79.3 % yield

Enzymatic synthesis of betulinic acid ester as an anticancer agent: optimization study

Immobilized Candida antarctica lipase, Novozym 435, was used to catalyze the esterification reaction between betulinic acid and phthalic anhydride to synthesize 3-O-phthalyl betulinic acid in n-hexane/chloroform. Response surface methodology based on a five-level, four-variable central composite rotatable design was employed to evaluate the effects of synthesis parameters such as reaction time, reaction temperature, enzyme amount and substrate molar ratio on the yield of ester. Based on the response surface model, the optimal enzymatic synthesis conditions were predicted to be: reaction time 20.3 h, reaction temperature 53.9°C, enzyme amount 145.6 mg, betulinic acid to phthalic anhydride molar ratio 1:1.11. The predicted yield was 65.8% and the actual yield was 64.7%

Controlling the Bullwhip Effect in a Supply Chain Network with an Inventory Replenishment Policy by a Robust Control Method

This paper develops a mathematical model using differential equations and considers a bullwhip effect in a supply chain network with multiple retailers and distributors. To ensure the stability of the entire system and reduce the bullwhip effect, a robust control method and an inventory replenishment policy are proposed. This shows that the choice of the output matrix may reduce the bullwhip effect. It has also observed in the inventory replenishment mechanism may be a negative impact on the robustness of the bullwhip effect. However, the inventory replenishment behavior may lead to the bullwhip effect on the presented model. This means that the complex supply relationships may have a significant role in controlling or reducing the bullwhip effect of fluctuations

Short-term and long-term monetary transmission policy based on structural vector auto regression model in Iran

The purpose of this article is to investigate the effects of monetary policy through monetary transmission channels (interest channel, exchange rate channel, credit channel and expectations channel) in the short and long term during the period 1386Q1-1396Q4. For this purpose, using the structural vector autoregression model of the effects Monetary policy was examined through channels. The experimental results obtained by estimating the relationships between variables using the SVAR approach based on statistical data show that in the short and long term, the exchange rate channel is the most effective channel in the transmission of monetary policy, so that the variable of expectations has both the most effect in the short term and long-term on this channel, after the exchange rate channel, there are expectations channel, and after that, credits and interest rate channel, which have the greatest impact in the short and long term, respectively.Finally, by examining the relative importance of monetary transfer channels to each other, it can be pointed out that with the passage of time, the influence of the channels will change, so that with price shocks, the expectations channel has the greatest impact in the short term, and the medium term of the effective money and the interest rate channel is effective in the long term

Insecticidal effects of zinc oxide nanoparticles and Beauveria bassiana TS11 on Trialeurodes vaporariorum (Westwood, 1856) (Hemiptera: Aleyrodidae)

Greenhouse whitefly, Trialeurodes vaporariorum is a major pest of horticultural and ornamental plants and is usually controlled with insecticides or biological control agents. In the current study, we examined the effects of synthesized zinc oxide nanoparticles (ZnO NPs) and Beauveria bassiana TS11 on T. vaporariorum adults. ZnO NPs were synthesized by precipitation method. Field emission scanning electron microscope images indicated that ZnO NPs were non-compacted uniformly. X-ray diffraction results confirmed the hexagonal wurtzite structure of ZnO NPs. Fourier transform infrared analysis showed an intense absorption peak at a range of 434-555 cm-1 related to Zn-O bond. In bioassays, adults were exposed to different concentrations of ZnO NPs (3, 5, 10, 15, 20 mg l-1) and fungi (104, 105, 106, 107, 108 spores ml-1). LC50 values for ZnO NPs and fungi were 7.35 mg l-1and 3.28×105 spores ml-1, respectively. Mortality rates obtained with ZnO NPs and fungi at the highest concentration were 91.6 % and 88.8 %, respectively. The results indicate a positive effect of ZnO NPs and B. bassiana TS11on adults. The current study was conducted under laboratory conditions, therefore, more studies are needed in field.</p

Growth and chondrogenic differentiation of mesenchymal stem cells derived from human adipose tissue on chitosan scaffolds

BACKGROUND AND OBJECTIVE: Treatment of cartilage damage for any reason is associated with temporary relief of joint pain. Providing the possibility of differentiating various stem cells into adult tissues can contribute to recovery and treatment of damaged cartilage tissue in skeletal system. In this study, chondrogenic potential of chitosan scaffold, CH-β-GP-HEC, with stem cells derived from human adipose tissue. METHODS: In this cross-sectional study, adipose tissue-derived stem cells were separated from abdomen of 15 patients who underwent inguinal hernia repair. 6-7×105 cells were cultured in plate one-dimensionally and on chitosan scaffold three-dimensionally for 21 days. MTT assay was run to evaluate the toxic effect of scaffold on cell viability. Proliferation and differentiation of cells were studied in the two types of culture after toluidine blue staining. To confirm the formation of cartilage, expression of collagen type II was assessed by immunohistochemistry. FINDING: In MTT assay, the average OD for cells cultured on scaffold is higher than 0. 8 compared with control group, which confirms the nontoxicity of scaffold for culturing stem cells (p>0. 05). Chondrogenic differentiation of cells on scaffold shows more glycosaminoglycan deposition in the extracellular matrix compared with one-layer culture. Moreover, in group with three-dimensional culture system, cells were spherical and the morphology of nucleus was different from one-layer culture. Regarding immunohistochemistry results, increased synthesis was observed in collagen type II as chondrogenesis markers in three-dimensional culture system compared with one-layer culture. CONCLUSION: Results of the study revealed that hydrogel scaffold, CH-β-GP-HEC, with porous structure provides a better environment for the growth of mesenchymal stem cells and their differentiation into cartilage tissue. © 2016, Babol University of Medical Sciences. All rights reserved

Paraoxonase phenotype distribution in a healthy Iranian population

Human serum paraoxonase (PON1) is a high-density lipoprotein-associated esterase that protects against organophosphate neurotoxicity, and is proposed to play a role in lipid metabolism and the onset of cardiovascular disease. In the present study, paraoxonase activities and phenotype distribution in serum of 132 healthy Iranian individuals aged 17-68 years were assessed using dual substrate method. In the study population, a wide interindividual variability (up to 15-fold) of paraoxonase activity was found. The mean of basal, salt-stimulated paraoxonase and arylesterase activities were 81.8 ± 57 U/ml, 153.1 ± 117.5 U/ml and 80.7 ± 12.8 kU/l, respectively. The ratio of salt-stimulated paraoxonase activity to arylesterase activity was used for definition of phenotypes. Based on the observed ratios, three distinct phenotypes AA (low activity), AB (intermediate activity) and BB (high activity) were determined. The PON1 ratio varied from 0.5 to 6.8. The paraoxonase phenotype frequencies were approximately 48 (AA), 41 (AB) and 11 (BB). In this work, serum triglycerides had significant positive correlation (r = 0.334, P < 0.05) with paraoxonase activity, whereas high-density lipoprotein did not. No significant decrease in paraoxonase activity by smoking was observed. Age and sex had no influences on PON1 activities. In conclusion, the distribution of paraoxonase phenotypes in this Iranian population was trimodal and comparable to that of Caucasians from North America; however, overall enzyme activity was lower than that reported for Caucasians. © 2007 The Authors

Synthesis and characterization of silver/montmorillonite/chitosan bionanocomposites by chemical reduction method and their antibacterial activity

Silver nanoparticles (AgNPs) of a small size were successfully synthesized using the wet chemical reduction method into the lamellar space layer of montmorillonite/chitosan (MMT/Cts) as an organomodified mineral solid support in the absence of any heat treatment. AgNO3, MMT, Cts, and NaBH4 were used as the silver precursor, the solid support, the natural polymeric stabilizer, and the chemical reduction agent, respectively. MMT was suspended in aqueous AgNO3/Cts solution. The interlamellar space limits were changed (d-spacing = 1.24–1.54 nm); therefore, AgNPs formed on the interlayer and external surface of MMT/Cts with d-average = 6.28–9.84 nm diameter. Characterizations were done using different methods, ie, ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray fluorescence spectrometry, and Fourier transform infrared spectroscopy. Silver/montmorillonite/chitosan bionanocomposite (Ag/MMT/Cts BNC) systems were examined. The antibacterial activity of AgNPs in MMT/Cts was investigated against Gram-positive bacteria, ie, Staphylococcus aureus and methicillin-resistant S. aureus and Gram-negative bacteria, ie, Escherichia coli, E. coli O157:H7, and Pseudomonas aeruginosa by the disc diffusion method using Mueller Hinton agar at different sizes of AgNPs. All of the synthesized Ag/MMT/Cts BNCs were found to have high antibacterial activity. These results show that Ag/MMT/Cts BNCs can be useful in different biological research and biomedical applications, including surgical devices and drug delivery vehicles