Fabrication of three-dimensionally printed polylactic acid nasal stent prosthesis for postnasal reconstruction using extraoral scanning and photogrammetry techniques: A report on two patients

Severe and combined nasal defects associated with trauma or neoplasm excision can cause significant functional and esthetic problems. To avoid nasal synechia following reconstructive surgeries, a nasal stent prosthesis is required to act as an internal scaffold to support the graft and residual tissues. The purpose of the stent is to maintain internal airway patency and to prevent collapse and contracture of the donor tissues. A conventional nasal stent prosthesis has disadvantages, including the difficulty in maintaining adequate thickness and internal patency during fabrication. Hence, this clinical report introduces the fabrication technique for 3- dimensionally printed polylactic acid nasal stent prostheses using extraoral scanning and photogrammetry methods.

Rehabilitation Using Hybrid Technique for Feeding Plate Fabrication in a 3-Month-Old Infant with Cleft Palate Defect Utilising Digital and Conventional Method: A Case Report

ABSTRACT

Cleft palate leads to difficulty in suckling, speech abnormalities, dental problems, hearing loss and middle ear infections. Feeding plate acts as a barrier between the oral and nasal cavities allowing the normal development of jaws and enhanced nutritional supply to the patient. Fabrication of the feeding plate using digital means provide better adaptability due to the engagement of all the possible favourable anatomic undercuts, thereby, providing better retention. This case report discusses the hybrid technique including both the digital and conventional means for fabrication of a feeding plate to obturate the defect between the oral and nasal cavity.

Rational design of thiazolidine-4-one-gallic acid hybrid derivatives as selective partial PPARγ modulators: an in-silico approach for type 2 diabetes treatment

Type 2 diabetes mellitus is a bipolar metabolic disorder characterized by abnormalities in insulin production from β-cells and insulin resistance. Thiazolidinediones are potent anti-diabetic agents that act through the modulation of the peroxisome proliferator-activated receptor γ (PPARγ), a nuclear receptor. However, their full agonistic activity leads to severe side effects by stabilizing Helix12 through strong hydrogen bonding with the TYR473 residue. Partial and selective PPARγ modulators (GW0072, GQ16, VSP-51, MRL-20, MBX-213, INT131) have demonstrated superior results compared to full agonists without causing adverse effects, as reported in existing data. To address this uncertainty and advance therapeutic options, we identified and designed a novel class of compounds (A1-A23) based on a hybrid structure combining phenolic and Thiazolidine-4-one's moieties. Our rational drug design strategy incorporated structural-activity relationship principle, and validated the docking studies through calculated the root mean square deviation. Additionally, we conducted molecular docking, binding energy, molecular dynamics simulations, and post-molecular dynamics calculations to evaluate the dynamics behavior between the ligands and protein. The selected ligands demonstrated highly favorable docking scores and binding energies, comparable to the co-crystal (rosiglitazone) such as A12 (-13.9 kcal/mol and -86.2 kcal/mol), A1 (-11.1 kcal/mol and -79.5 kcal/mol), A13 (-11.3 kcal/mol and -91.4 kcal/mol), and the co-crystal itself (-9.8 kcal/mol and -76 kcal/mol), respectively. Finally, the MD revealed that, the selected ligands were equally contributed for stabilization of Helix12 and β-sheets. It was concluded, the designed ligands (A12, A1, and A13) exhibited weaker hydrogen-bond interactions with specific residue TYR473 which partially modulated the PPARγ protein.Communicated by Ramaswamy H. Sarma.

Validation of candidate gene-based EST-SSR markers for sugar yield in sugarcane

Sugarcane (Saccharum spp.) is a widely cultivated crop that fulfils approximately 75% of the sucrose demand worldwide. Owing to its polyploidy and complex genetic nature, it is difficult to identify and map genes related to complex traits, such as sucrose content. However, association mapping is one of the alternatives for identifying genes or markers for marker-assisted selection. In the present study, EST-SSR primers were obtained from in silico studies. The functionality of each primer was tested using Blast2Go software, and 30 EST-SSR primers related to sugar content were selected. These markers were validated using association analysis. A total of 70 F1 diverse genotypes for sugar content were phenotypes with two check lines. All parameters related to sugar content were recorded. The results showed a significant variation between the genotypes for sugar yield traits such as Brix value, purity, and sucrose content, etc. Correlation studies revealed that the Brix%, sucrose content, and sucrose recovery were significantly correlated. An association analysis was performed using mixed linear model to avoid false positive associations. The association analysis revealed that the SEM 407 marker was significantly associated with Brix% and sucrose content. The SEM 407 primers are putatively related to diphosphate-fructose-6-phosphate 1-phosphotransferase which is associated with Brix% and sucrose content. This functional marker can be used for marker-assisted selection for sugar yield traits in sugarcane that could accelerate the sugarcane breeding program.

Anterior esthetic rehabilitation with full and partial veneers using conventional and digital techniques: A case series

Effective esthetic rehabilitation requires a proper treatment planning in addition to the associated diagnostic wax-up. For anterior rehabilitation, most dentists favor conservative and esthetic treatments, such as indirect laminate veneer restorations which can be partial- or full-ceramic anterior crowns according to the clinical situations. After the introduction of technologies such as intraoral scanners, dental software for digital restoration design, and additive manufacturing (three-dimensional printing), these techniques further enhanced the digital workflow of restorative therapy. These technologies also fabricate prosthesis with natural esthetics and marginal integrity. This case series discusses the conventional and digitally fabricated full- and partial-ceramic veneers for discolored and misaligned anterior teeth after the fabrication of corresponding diagnostic wax-up.

Surgical Rehabilitation of a Continuous Orbital and Maxillary Defect from Rhino-Orbital Mucormycosis Utilising Digital Technology - A Case Report

Rationale

COVID-19 has led to a resurgence in cases of mucormycosis, especially the rhino-orbital form affecting the oral cavity, nasal, orbital and cerebral regions.

Patient Concerns

The surgical treatment in this patient led to the exenteration of orbital contents and segmental maxillectomy of the affected side leading to facial disfigurement and inability to masticate.

Diagnosis

A combined mucormycosis-associated oro-orbital defect was present leading to a communication between oral and orbital cavities.

Treatment

Rehabilitation utilising digital technology for removable prosthesis was planned for the combined orbital and oral defect.

Outcomes

The independent intraoral and orbital prosthesis reduced the mobility of the orbital prosthesis while performing functional movements. The advancements in digital technology led to the convenient and resilient fabrication of prostheses for large facial defects.

Take-away Lessons

The prosthetic rehabilitation of a continuous orbital and oral defect with a hybrid of both digital and conventional means provided an aesthetic, feasible and financially sound solution to the patient.

Magnet-Retained closed bulb hollow obturator and orbital prosthesis for patient with maxillectomy and orbital exenteration following COVID-Associated mucormycosis

The rehabilitation of facial deformities is a challenging endeavour that necessitates customising the procedure for each patient. Significant physical and psychological impacts might arise as a result of the deformity in the orofacial region. Post-COVID rhino-orbital mucormycosis has led to rise in extraoral and intraoral defects since 2020. To avoid further surgery, an economical maxillofacial prosthesis is an excellent choice as it is aesthetic, durable, long-lasting and retentive. This case report describes the prosthetic rehabilitation of the patient with post-COVID mucormycosis maxillectomy and orbital exenteration using a magnet-retained closed bulb hollow acrylic obturator and room-temperature vulcanising silicone orbital prosthesis. To enhance retention, a spectacle and medical-grade adhesive were also used.

Prosthetic Rehabilitation Following Segmental Maxillectomy Confluent with an Orbital Defect Using a Hollow Orbital Prosthesis Retained Magnetically with an Obturator: A Case Report

Loss of a sense organ, such as an eye in situations of orbital involvement, or any other bodily part, such as the maxilla or palate, might make one more dependent on others for care and affect how they perceive themselves in society. The prosthetic rehabilitation of large mid-facial defects is a challenging task due to the varied size and shape of the defect. Confluent maxillary and orbital abnormalities are best restored with prosthetic means by creating a comfortable, aesthetically pleasing prosthesis that allows for the restoration of speech, deglutition, and mastication. The retention of any prosthesis is must for it to be successful. The hollow orbital conformer described in this case presentation aids in reducing the weight of the prosthesis, thereby enhancing the retention of the prosthesis. This clinical case presentation highlights the aesthetic and functional rehabilitation using a combined obturator-orbital prosthesis connected using intraoral magnets.

Resin-bonded bridge as a simplified approach to restore missing teeth in esthetic zone by conventional and digital techniques

One of the most challenging esthetic concerns in dentistry is conservative replacement of the missing anterior teeth. Although implants are considered to be a better treatment option for rehabilitation of such patients, resin-bonded bridges (RBBs) can conservatively restore the missing teeth and have thus gained popularity over the years. It consists of an artificial tooth with a wing-like extension that is cemented to the adjacent teeth. There are various types of RBBs among which Maryland bridge is the simplest and the popular most due to its micromechanical retention enabled by acid etching of both tooth and metal retainer. It can be fabricated by various techniques and materials. In this case reports, we have discussed about two unique designs of Maryland bridge fabricated by two different materials (Porcelain-fused metal and Graphene) and utilizing two different techniques (conventional and digital).

Aesthetic rehabilitation of amputated phalanx by three part mould technique using silicone elastomer – case report

The unfortunate loss of all or part of a finger caused by traumatic amputation has a negative impact on physical and psychological well-being of a person. Thus an aesthetic prosthesis can offer psychological, functional and rehabilitative advantages. One of the major problems with the prosthetic replacement of a partially amputated finger is inadequate retention of the prosthesis and there are numerous means to enhance the retention. The most routinely used are adhesives, adhesive tape, magnets and implants. The present article describes a technique which utilizes room temperature vulcanizing silicone (RTV) as a prosthetic material retained by preformed artificial rings. Such treatment can be opted for in cases of financial constraints.

Implant-Supported Hybrid Prosthesis using All on Six Concept for Atrophic Ridges with Severe Gag Reflex: A Case Report

Aims: Edentulism is correlated to poor self-esteem and depression in both young and old individuals due to social rejection. For edentulous patients who are not interested in removable prosthesis, implant-supported fixed prosthesis might be an appropriate treatment modality. The aim of this case report is to rehabilitate the completely edentulous patient with severe gag reflex by maxillary implant supported hybrid prosthesis and mandibular conventional complete denture. Presentation of case: A 58 years old female patient had reported to the outpatient wing of department of prosthodontics with chief complaint of missing teeth in maxillary and mandibular arches. Patient had a history of severe gagging and discomfort with old denture. The treatment progresses as six implant placed and hybrid prosthesis was fabricated in maxillary arch and conventional complete denture was fabricated in mandibular arch and delivered to the patient. Discussion: Implant-supported complete arch rehabilitation can be accomplished with either a fixed or removable prosthesis. For a satisfactory outcome, proper patient selection, accurate surgical procedure, and meticulous prosthetic planning are required. Cement-retained implant restorations are becoming more popular because they are simple, aesthetic, and cost-effective. However, such restorations are hard to retrieve, and any residual cement in the soft tissue around the implant might cause peri-implant illness. Conclusion: A screw retained fixed prosthesis was planned for this patient in maxillary arch and conventional complete denture in mandibular arch which gave a successful outcome and avoid gag reflex.

Ropinirole, a potential drug for systematic repositioning based on side effect profile for management and treatment of breast cancer

Drug repositioning offers two main advantages in drug discovery - the process is less tedious and less costly. In the past, many drugs like thalidomide and sildenafil were successfully repositioned but the process was entirely serendipitous. These days drug repositioning is widely accepted as an alternate method of drug discovery and the process is based on building a strong hypothesis guided by systematic computational and experimental methods. One of the methods used in drug repositioning is based on shared side effects by drugs of different pharmacological categories. This method rests on the principle that drugs that share side effects might also share common biological targets and therefore same pharmacological indications. Old drugs can be repositioned for new uses by identifying the shared side effects of existing drugs and by modulating their chemical structure if required. Breast cancer is the most common type of cancer in women and the second leading cause of death worldwide after lung cancer in both men and women. Letrozole, an aromatase inhibitor, is used in the treatment of advanced, recurrent and metastatic breast cancer in post-menopausal women. Identification of drugs that share side effects with letrozole might help us to identify a potential drug for repositioning in the treatment of breast cancer. Ropinirole, a dopaminergic agonist was found to share the maximum number of side effects with letrozole. Studies have proposed that dopaminergic agonists induce apoptosis in breast, colon, ovarian cancer cells and leukemia neuroblastoma. This is consistent with our hypothesis that ropinirole that shares the maximum number of side effects with letrozole might be effective in the management of breast cancer. This hypothesis was further validated by preliminary molecular docking and in-vitro cell-line studies.

Cerebral ischemia induced inflammatory response and altered glutaminergic function mediated through brain AT1 and not AT2 receptor

In the present study, we investigated the effects of angiotensin (Ang II) receptor blockers in cerebral ischemia by administration of telmisartan (AT₁ blocker) and/or PD123319 (AT₂ blocker) in global ischemic mice model. The neuroprotective effect of AT antagonists was evaluated through monitoring muscle co-ordination and cerebral blood perfusion in ischemic mice. Gene expression studies (NF-κB, GSK-3β, EAAT-2, AT₁ & AT₂ receptors) and staining of brain regions with cresyl violet, GFAP, synaptophysin and NSE methods were carried out in to understand the molecular mechanisms. Further, the brain glutamate, cytokines, and Ang II peptide levels were evaluated and their correlation with EAAT-2 mRNA expression was performed. Our results indicate that the induction of ischemia elevates brain Ang II, cytokines, and glutamate levels and reduced muscle co-ordination and cerebral blood perfusion. The expressions of NF-κB, GSK-3β and AT₁ were significantly increased, whereas, EAAT-2 expression was decreased. Blocking of AT₁ receptors by telmisartan (TM) reversed the detrimental responses of cerebral ischemia and restored the cerebral blood flow denoting blockade of Ang II/AT₁ pathway is beneficial in ischemia, whereas, blockade of AT₂ receptors by PD123319 (PD) increased the ischemic injury in mice. This vulnerable effect of PD may be attributed through augmenting the Ang II/AT₁ dependent cytokines mediated glutamate transporter (EAAT-2) dysfunction. Interestingly, the beneficial effects of AT₁ blocker was remarkably antagonized by AT₂ blocker in most of the parameters studied in ischemic conditions. Also, the expression of AT₂ receptors was significantly increased compared to that of AT₁ receptors upon ischemic induction. It denotes that the endogenous Ang II predominantly acts on AT₂ receptor, thereby promoting its own mRNA transcription. Hence, the increased expression of AT₂ receptors in ischemic condition could be used as target protein for therapeutic benefit.

Iminoenamine based novel androgen receptor antagonist exhibited anti-prostate cancer activity in androgen independent prostate cancer cells through inhibition of AKT pathway

Treatment by androgen receptor (AR) antagonists is one of the regimens for prostate cancer. The prolonged treatment with AR antagonist leads to the expression of point mutation in the ligand binding domain of the AR. This point mutation causes resistance to AR antagonist by converting them into an agonist. The T887A mutated AR was frequently expressed in androgen independent prostate cancer (AIPC) patients. Through literature survey and molecular modelling, we have identified a novel AR antagonist having a bulky β-iminoenamine BF2 complex scaffold. The tested and standard ligands were screened in AR positive (LNCaP, MCF-7 and MDA-MB-453), AR negative (PC3), and non-cancerous (3T3) cell lines through anti-proliferation assay. The ligand, ARA3 was the most potent molecule among all the tested ligands and was 7.6 folds selective for AR positive cell lines. The mechanism of anti-prostate cancer activity of ARA3 was confirmed by western blot, qPCR, and apoptotic assays in LNCaP (T887A positive AR) cells. Structural activity relationship was derived by correlating the in-vitro and in-silico data. Consequently, we have identified the essential functional groups that could prevent the resistance concerning mutant AR. The ARA3 induces the apoptosis in AIPC cells by preventing the AR mediated activation of AKT pathway. The bicalutamide did not induce the apoptosis because it failed to prevent the AR mediated activation of AKT.

4-[2-(1,3-Dioxoisoindolin-2-yl)-1,3-thiazol-4-yl]benzonitrile

The title isoindole, C18H8N3O2S, crystallizes with two independent molecules (AandB) in the asymmetric unit whose geometrical features are similar. The benzonitrile ring is oriented at an angle of 2.1 (1)° (moleculeA) and 16.0 (1)° (moleculeB), with respect to the isoindole ring system. In the crystal,Amolecules are linkedviaC—H...N hydrogen bonds, formingC(15) chains propagating along along thecaxis.Bmolecules are linkedviaC—H...O interactions, forming dimers with anR22(10) graph-set motif. C—H...O and C—H...N interactions, charcterized byR22(15) andR21(7) motifs, are observed between moleculesAandB.

2-Chloro-N-(4-phenyl-1,3-thiazol-2-yl)acetamide

The title acetamide, C11H9ClN2OS, crystallizes with two independent molecules in the asymmetric unit whose geometrical features are similar. The phenyl ring is oriented at angles of 2.5 (1) and 6.2 (1)° with respect to the thiazole ring in the two molecules. In the crystal, molecules are linkedviaC—H...N hydrogen bonds which formC(10) chains along the [-100] direction. The chains are linked by N—H...O and C—H...O hydrogen bonds, formingC(8) chains along the [100] direction.

Intracellular mannose binding lectin mediates subcellular trafficking of HIV-1 gp120 in neurons

Human immunodeficiency virus-1 (HIV-1) enters the brain early during infection and leads to severe neuronal damage and central nervous system impairment. HIV-1 envelope glycoprotein 120 (gp120), a neurotoxin, undergoes intracellular trafficking and transport across neurons; however mechanisms of gp120 trafficking in neurons are unclear. Our results show that mannose binding lectin (MBL) that binds to the N-linked mannose residues on gp120, participates in intravesicular packaging of gp120 in neuronal subcellular organelles and also in subcellular trafficking of these vesicles in neuronal cells. Perinuclear MBL:gp120 vesicular complexes were observed and MBL facilitated the subcellular trafficking of gp120 via the endoplasmic reticulum (ER) and Golgi vesicles. The functional carbohydrate recognition domain of MBL was required for perinuclear organization, distribution and subcellular trafficking of MBL:gp120 vesicular complexes. Nocodazole, an agent that depolymerizes the microtubule network, abolished the trafficking of MBL:gp120 vesicles, suggesting that these vesicular complexes were transported along the microtubule network. Live cell imaging confirmed the association of the MBL:gp120 complexes with dynamic subcellular vesicles that underwent trafficking in neuronal soma and along the neurites. Thus, our findings suggest that intracellular MBL mediates subcellular trafficking and transport of viral glycoproteins in a microtubule-dependent mechanism in the neurons.

SU-E-T-649: Evaluation of RapidArc- Based Stereotactic Cranial Radiotherapy Plans with MU Objective Using Multiple Non Coplanar Arcs in Comparison with Conventional Dynamic Conformal Arc Technique

PURPOSE

Previous researches reported that RapidArc plans for stereotactic cranial radiotherapy have two to three times more MUs as compared to Conventional Dynamic Conformal Arc (DCA) Technique. This study aims to evaluate RapidArc plans using multiple non- coplanar arcs, developed with MU objective constraint in the optimization stage.

METHODS

Five single brain metastasis and three multiple metastases cases previously planned using DCA techniques in BrainLab iPlan Version 4.1 were investigated in this study. For each case, the target was defined on CT-MR fused images in iPlan. The CT images and contours of these patients were exported from iPlan to Varian Eclipse TPS Version 8.6. For each case, a DCA plan and a RapidArc plan with multiple non-coplanar arcs with and without using MU objective in the optimization stage were generated using Varian Trilogy machine with Millennium 120 MLC keeping the same prescription and critical structure dose limits. All plans were evaluated according to Conformity Index (CI-modified Paddick) Homogeneity Index (HI), and the normal tissue volume receiving various dose levels (V80%, V50%, V25% and V10%).

RESULTS

In all the plans, the target objectives were met and dose to OARs was within tolerance dose constraints. RapidArc plans with and without MU objective showed better CI and HI as supposed to DCA plans. V80%, V50%, V25% and V10% of normal tissue for RapidArc plans are equal or lesser than DCA plans. Single isocentre RapidArc plan for closely spaced multiple metastases cases showed better dose fall off between the lesions as supposed to DCA plans. RapidArc plans with MU objective resulted in comparable MUs as that of DCA plans.

CONCLUSIONS

Our study showed RapidArc plans done with and without MU objective have no significant dosimetric difference in plan objectives. Therefore, multiple non-coplanar RapidArc plans with MU objective is clinically feasible and can provide better treatment plans than conventional DCA plans, especially for complicated cases.

Identification of difurocumenonol, a new antimicrobial compound from mango ginger (Curcuma amada Roxb.) rhizome

AIM

The aim of the present work was to purify and characterize potential natural antibacterial compound from mango ginger (Curcuma amada Roxb.) rhizome.

METHODS AND RESULTS

The mango ginger rhizome powder was sequentially extracted and screened for antibacterial activity by agar well diffusion method and broth dilution method. Nonpolar extracts of mango ginger showed high antibacterial activity against gram-positive bacteria with low minimum inhibitory concentration (60-180 ppm). Among five extracts of mango ginger, the chloroform extract demonstrated highest antibacterial activity. Antibacterial activity-guided fractionation of the chloroform extract by repeated silica gel column chromatography yielded pure compound. The purified antibacterial compound was analysed by UV, IR, LC-MS and 2D-HMQCT NMR spectra and was identified as a difurocumenonol, a novel compound not reported previously.

CONCLUSIONS

Mango ginger extracts and isolated difurocumenonol demonstrated high antibacterial activity against gram-negative and gram-positive bacteria.

SIGNIFICANCE AND IMPACT OF THE STUDY

A novel and natural antibacterial compound as well as mango ginger extracts can be used as food preservative to control the growth of food-borne pathogens and as a source of mango flavour.

Isolation and characterization of dihydromonacolin-MV from Monascus purpureus for antioxidant properties

The methanolic extract of Monascus purpureus cultivated by solid-state fermentation on rice showed strong 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and better yield as compared to other polarity based extracted fractions. It was selected for further purification of the antioxidant. The activity-guided repeated fractionation of methanolic extract on a silica gel column chromatography yielded a compound that exhibited strong antioxidant activity. Based on the spectroscopic analysis by UV, IR, 1H NMR, 13C NMR, 2D-HSQCT NMR, and MS, the antioxidant isolated was elucidated as a derivative of dihydromonacolin-K, where the ester group is 2-methyl propionate, designated as dihydromonacolin-MV. The DPPH radical was significantly scavenged by the dihydromonacolin-MV (IC50 20+/-1 microg ml-1). The dihydromonacolin-MV showed strong inhibition of lipid peroxidation in a liposome model with an IC50 value of 5.71+/-0.38 microg ml-1 and superoxide radical scavenging activity with an IC50 value of 163.97+/-2.68 microg ml-1.

Glycosides and amino acyl esters of carbohydrates as potent inhibitors of angiotensin converting enzyme

About 12 glycosides prepared through amyloglucosidase catalysis and 23 amino acyl esters of carbohydrates prepared through lipase catalysis in organic solvents showed angiotensin converting enzyme (ACE) inhibition activity. Both amino acyl esters of carbohydrates and glycosides exhibited IC50 values for ACE inhibition in the 0.5 mM to 15.7 mM range. Eugenyl-D-glucoside (IC50: 0.5+/-0.04 mM), L-isoleucyl-D-glucose (IC50: 0.7+/-0.067 mM), vanillyl-D-sorbitol (IC50: 0.8+/-0.09 mM), L-histidyl-D-fructose (IC50: 0.9+/-0.087 mM), L-tryptophanyl-D-fructose (IC50: 0.9+/-0.092 mM), octyl-D-glucoside (IC50: 1.0+/-0.093 mM), vanillyl-D-mannoside (IC50: 1.0+/-0.089 mM), L-valyl-D-mannitol (IC50: 1.0+/-0.092 mM) and L-phenylalanyl-D-glucose (IC50: 1.0+/-0.089 mM) were the compounds, which showed the best ACE inhibitory activities.

Angiotensin converting enzyme inhibitory activity of amino acid esters of carbohydrates

L-alanyl-D-glucose, L-valyl-D-glucose, L-phenylalanyl-D-glucose and L-phenylalanyl-lactose esters were synthesized enzymatically using two lipases viz., Rhizomucor miehei lipase (RML) and porcine pancreas lipase (PPL) and tested for their potential as inhibitors of angiotensin converting enzyme (ACE) in vitro. The esters exhibited concentration related ACE inhibitory activity. The potency of the various esters measured in terms of IC50 values were as follows: L-phenylalanyl-D-glucose, IC50-0.121 mM (mixture of five diastereomeric esters: 6-O-24.1%; 3-O-23.3%; 2-O-19.2%; 2,6-di-O-16.6% and 3,6-di-O-16.8% from the total yield of 92.4%); L-phenylalanyl-lactose, IC50-0.229 mM (mixture of three diastereomeric esters: 6-O-42.1%; 6'-O-30.9%; and 6,6'-di-O-27.0% from the total yield of 50.58%); alanyl-D-glucose, IC50-0.23 mM (mixture of five diastereomeric esters: 6-O-46.7%; 3-O-11.5%; 2-O-19.9%; 2,6-di-O-6.6% and 3,6-di-O-15.3% from the total yield of 26.5%) and L-valyl-D-glucose, IC50-0.396 mM (mixture of five diastereomeric esters: 6-O-32.4%; 3-O-26.5%; 2-O-26.4%; 2,6-di-O-8.8% and 3,6-di-O-5.9% from the total yield of 68.2%). These in vitro data suggest a potential therapeutic role for the aminoesters of carbohydrates as inhibibitors of ACE.

Isolation of antioxidant compounds from the methanolic extract of the roots of Decalepis hamiltonii (Wight and Arn.)

The tuberous roots of Decalepis hamiltonii are consumed as pickles and beverages and are believed to possess health-promoting properties. We have investigated the antioxidant potential of the roots. The methanolic extract of the root showed a high antioxidant activity. The methanolic extract was fractionated on a silica gel column, which showed three major fractions with good antioxidant activity. The active fractions were further subjected to preparative thin layer and silica gel column chromatography, which yielded six pure compounds. The purified compounds were characterized by MS, 1H NMR, 13C NMR, and two-dimensional NMR spectroscopic techniques and identified as 2-hydroxy-4-methoxybenzaldehyde, p-anisaldehyde, vanillin, borneol, salicylaldehyde, and bis-2,3,4,6-galloyl-alpha/beta-D-glucopyranoside. The latter compound, named decalepin, is a new antioxidant molecule from the plant kingdom. The purified compounds showed antioxidant activities in in vitro assays such as inhibition of lipid peroxidation, hydroxyl radical, superoxide anion, and 1,1-diphenyl-2picrylhydrazyl radical scavenging. This is the first report of the antioxidant constituents of the roots of Decalepis hamiltonii.

Nigerloxin, a novel inhibitor of aldose reductase and lipoxygenase with Free radical scavenging activity from Aspergillus niger CFR-W-105

An enzyme inhibitor, nigerloxin, with inhibition against soy bean lipoxygenase-I (LOX-1), rat lens aldose reductase (RLAR) as well as free radical scavenging activity was isolated from the fermented wheat bran using Aspergillus niger CFR-W-105. Its chemical structure was identified as 2-amido-3-hydroxy-6-methoxy-5-methyl-4-(prop-1'-enyl) benzoic acid by NMR and GCEIMS data. The IC50 values against LOX-1 and RLAR were found to be 79 microM and 69 microM and ED50 against 1,1-diphenyl-2-picrylhydrazyl (DPPH) was 66 microM.

Hydrogen ions in microaqueous phase during lipase catalysed esterification in non-aqueous media

Lipase catalysed stearoyl lactic acid preparation in non-aqueous media was treated as a model system to study the microaqueous phase containing hydrogen ions arising from dissociation of water soluble lactic acid in it. The thermodynamic factors operating at the microaqueous enzyme-water-solvent phase on the lipase in non-polar solvents were investigated in terms of the water of reaction which constitutes the microaqueous phase, partitioning of acid between water of the microaqueous phase and the organic solvent, dissolution and dissociation of the acid and the resultant number of H+ present in the microaqueous phase and the extent of esterification for a given amount of enzyme at various substrate concentrations. Using mass transfer equations, the theoretical number of H+ at the microaqueous phase were calculated and expressed as hydrogen ion numbers to generate plots which indicated various thermodynamic processes operating at the microaqueous phase to maintain this concentration to a safe minimum.

Enzymatic synthesis of isoamyl acetate using immobilized lipase from Rhizomucor miehei

The effects of important reaction parameters for enhancing isoamyl acetate formation through lipase-catalyzed esterification of isoamyl alcohol were investigated in this study. Increase in substrate (acid) concentration led to decrease in conversions. A critical enzyme concentration of 3 g l(-1) was detected for a substrate concentration of 0.06 M (each of alcohol and acid). Solvents with partition coefficient higher than 1000 (log P>3.0) supported enzyme activity to give high conversions. Acetic acid at higher concentrations could not be esterified easily probably owing to its role in lowering the microaqueous pH of the enzyme. Extraneous water/buffer addition decreased the isoamyl acetate yields slightly ( approximately 10%) at 0.005-0.01% v/v of the reaction mixture and drastically (>40%) at above 0.01% v/v. Buffer saturation of the organic solvent employed improved esterification (upto two-fold), particularly at moderately higher substrate concentrations (>0.18 M). Employing acetic anhydride instead of acetic acid resulted in a two-fold increase in the yields (at 0.25 M substrate). Use of excess nucleophile (alcohol) concentration by increasing the alcohol/acid molar ratio resulted in higher conversions in shorter duration (upto eight-fold even at 1.5 M acetic acid). Yields above 80% were achieved with substrate concentrations as high as 1.5 M and more than 150 g l(-1) isoamyl acetate concentrations were obtained employing a relatively low enzyme concentration of 10 g l(-1). The operational stability of lipase was also observed to be reasonably high enabling ten reuses of the biocatalyst.

Lipase catalyzed synthesis of organic acid esters of lactic acid in non-aqueous media

Lipases from Rhizomucor miehei (Lipozyme IM20) and porcine pancreas (PPL) were employed as catalysts for the esterification reaction between the hydroxyl group of lactic acid and the carboxyl group of organic acids. Reactions were carried out at both shake-flask and bench-scale levels. Various parameters, such as solvent, temperature, substrate and enzyme concentrations, effect of buffer volume, buffer pH and water volume, were investigated for optimization of yields. While ethylmethyl ketone (EMK) was found to be the best solvent for shake-flask reactions, chloroform gave higher yields at bench-scale level. Detailed studies were carried out with respect to the synthesis of palmitoyl and stearoyl lactic acids. At shake-flask level, maximum yields of 37.5 and 40% were observed in case of palmitoyl and stearoyl lactic acids, respectively, with Lipozyme IM20; at bench-scale level, the maximum yields were 85.1 and 99% respectively, when PPL was employed. Of all the organic acids employed (C(2)--C(18)), only lauric, palmitic and stearic acids gave yields above 50%. At bench-scale level, PPL could be reused for up to three cycles with yields above 40%. Esters prepared were found to conform to Food Chemical Codex (FCC) specifications in terms of acid value, ester value, sodium and lactic acid contents.