R software for QSAR analysis in phytopharmacological studies.

INTRODUCTION: In recent decades, quantitative structure-activity relationship (QSAR) analysis has become an important method for drug design and natural product research. With the availability of bioinformatic and cheminformatic tools, a vast number of descriptors have been generated, making it challenging to select potential independent variables that are accurately related to the dependent response variable. OBJECTIVE: The objective of this study is to demonstrate various descriptor selection procedures, such as the Boruta approach, all subsets regression, the ANOVA approach, the AIC method, stepwise regression, and genetic algorithm, that can be used in QSAR studies. Additionally, we performed regression diagnostics using R software to test parameters such as normality, linearity, residual histograms, PP plots, multicollinearity, and homoscedasticity. RESULTS: The workflow designed in this study highlights the different descriptor selection procedures and regression diagnostics that can be used in QSAR studies. The results showed that the Boruta approach and genetic algorithm performed better than other methods in selecting potential independent variables. The regression diagnostics parameters tested using R software, such as normality, linearity, residual histograms, PP plots, multicollinearity, and homoscedasticity, helped in identifying and diagnosing model errors, ensuring the reliability of the QSAR model. CONCLUSION: QSAR analysis is vital in drug design and natural product research. To develop a reliable QSAR model, it is essential to choose suitable descriptors and perform regression diagnostics. This study offers an accessible, customizable approach for researchers to select appropriate descriptors and diagnose errors in QSAR studies.

Osteoarthritis: Prognosis and emerging therapeutic approach for disease management.

Osteoarthritis (OA), a disorder of joints, is prevalent in older age. The contemporary cure for OA is aimed to confer symptomatic relief, consisting of temporary pain and swelling relief. In this paper, we discuss various modalities responsible for the onset of OA and associated with its severity. Inhibition of chondrocytes receptors such as DDR2, SDF-1, Asporin, and CXCR4 by specific pharmacological inhibitors attenuates OA, a critical step for finding potential disease modifying drugs. We critically analyzed recent OA studies with an emphasis on intermediate target molecules for OA intervention. We also explored some novel and safe treatments for OA by considering disease prognosis crosstalk with cellular signaling pathways.

A novel phytochemical from Dipteris wallichii inhibits human ß-secretase 1: Implications for the treatment of Alzheimer's disease.

Alzheimer's disease (AD) is the most prevalent progressive neurodegenerative disease, and the most common cause of dementia. One of the histopathological hallmarks of AD is the accumulation of extracellular amyloid-ß (Aß) oligomers as neuritic plaques in brain. The Aß oligomers are produced from amyloid precursor protein by the action of secretase enzymes, among which ß-secretase 1 (BACE1) catalyses the rate-limiting step. Thus, BACE1 is one of the most important therapeutic targets in preventing deposition of the plaques, progression of the disease, and thus as a disease-modifying therapeutic strategy. The present study was undertaken to isolate and identify novel phytochemicals from the pteridophyte Dipteris wallichii, and to determine their pharmacological properties. A novel compound was eventually detected and named Dip-1, and its pharmacological properties were predicted using computational modelling. The compound was found to have pharmacophores similar to those of known BACE1 inhibitors. Thus, further studies were performed to determine its drug likeness, blood-brain barrier (BBB) permeability, inhibitory potential and IC50 value. The results were promising, and the compound was found to have high drug likeness and BBB permeability, and a potent inhibitor of BACE1, with IC50 value of 0.0372 nM. Thus, the present study reports a novel BACE1 inhibitor from the plant D. wallichii, and is significant owing to its therapeutic implication as a disease-modifying therapy for AD.

Effect of single-dose carbapenem exposure on transcriptional expression of blaNDM-1 and mexA in Pseudomonas aeruginosa.

The therapeutic option of a carbapenem antibiotic is compromised in Pseudomonas aeruginosa owing both to acquired and intrinsic resistance mechanisms. In recent years, New Delhi metallo-ß-lactamase has been the focus as a predominant carbapenem resistance determinant. However, it is unclear which of the mechanisms might be adopted by a P. aeruginosa strain possessing both blaNDM-1 and an overexpressed MexAB-OprM system during carbapenem therapy. This study investigated the interplay of both mechanisms in clinical isolates of P. aeruginosa when exposed to meropenem. Five strains were used: (i) strain overexpressing MexAB-OprM but with no blaNDM-1; (ii) strain harbouring blaNDM-1 but expressing MexAB-OprM at basal level; (iii) strain possessing blaNDM-1 and overexpressing MexAB-OprM; (iv) P. aeruginosa PAO1; and (v) P. aeruginosa K2733-PAO1 (ΔMexAB-OprMΔMexCD-OprJΔMexEF-OprNΔMexXY-OprM) into which blaNDM-1 was cloned. Strains were incubated in Luria-Bertani broth with and without 1µg/mL meropenem. Total RNA was isolated at 45-min intervals and was immediately reverse transcribed to cDNA. This was repeated for 6h. Quantitative real-time PCR was performed for both resistance mechanisms. Meropenem exposure did not significantly elevate transcription of either the blaNDM-1 or mexA gene. However, an interesting finding was that upon single-dose exposure to carbapenem, the efflux pump system played a major role in bacterial survival compared with NDM-1. This study gives an insight into the bacterial response to carbapenem antibiotic when two different resistance mechanisms coexist. This type of study would be helpful in designing future antimicrobials.

Cicca acida L.: phytochemistry and pharmacological studies.

OBJECTIVES: Cicca acida L., is reported with traditional and pharmacological uses, and a good number of pure compounds have been isolated from its different parts. But published information is sporadic and fragmentary in nature. Therefore, it is imperative to have a comprehensive account of all of its medicinal potentialities with critical analysis. In this review, the traditional reports, phytochemical and pharmacology studies associated with Cicca acida have been compiled to figure out the net possibilities for its application in modern medicine. KEY FINDINGS: Careful scrutiny reveals that the plant possesses a huge range of medicinal properties, but published report analysis suggests that the plant is effectively used as antibacterial, hepatoprotective, anticonceptive and antidiabetic purposes. The published papers revealed the bioactivity of only 04 compounds. This indicates that a good number of isolated major compounds of this plant are yet to be pharmacologically investigated. CONCLUSION: Intensive study of Cicca acida showed that despite of its plentiful isolated molecules, the effort leading to final product stage seems to be less. Therefore, the plant and its compounds need concentrated effort towards establishment of its therapeutic potentialities.

Premature Termination of MexR Leads to Overexpression of MexAB-OprM Efflux Pump in Pseudomonas aeruginosa in a Tertiary Referral Hospital in India.

OBJECTIVES: The present study was undertaken to investigate the mutations that are present in mexR gene of multidrug resistant (MDR) isolates of Pseudomonas aeruginosa collected from a tertiary referral hospital of north east India. METHODS: 76 MDR clinical isolates of P. aeruginosa were obtained from the patients who were admitted to or attended the clinics of Silchar medical college and hospital. They were screened phenotypically for the presence of efflux pump activity by an inhibitor based method. Acquired resistance mechanisms were detected by multiplex PCR. Real time PCR was performed to study the expression of mexA gene of MexAB-OprM efflux pump in isolates with increase efflux pump activity. mexR gene of the isolates with overexpressed MexAB-OprM efflux pump was amplified, sequenced and analysed. RESULTS: Out of 76 MDR isolates, 24 were found to exhibit efflux pump activity phenotypically against ciprofloxacin and meropenem. Acquired resistance mechanisms were absent in 11 of them and among those isolates, 8 of them overexpressed MexAB-OprM. All the 8 isolates possessed mutation in mexR gene. 11 transversions, 4 transitions, 2 deletion mutations and 2 insertion mutations were found in all the isolates. However, the most significant observation was the formation of a termination codon at 35th position which resulted in the termination of the polypeptide and leads to overexpression of the MexAB-OprM efflux pump. CONCLUSIONS: This study highlighted emergence of a novel mutation which is probably associated with multi drug resistance. Therefore, further investigations and actions are needed to prevent or at least hold back the expansion and emergence of newer mutations in nosocomial pathogens which may compromise future treatment options.

Transcriptional Analysis of MexAB-OprM Efflux Pumps System of Pseudomonas aeruginosa and Its Role in Carbapenem Resistance in a Tertiary Referral Hospital in India.

Carbapenem resistance presents severe threat to the treatment of multidrug resistant Pseudomonas aeruginosa infections. The study was undertaken to investigate the role of efflux pumps in conferring meropenem resistance and effect of single dose exposure of meropenem on transcription level of mexA gene in clinical isolates of P. aeruginosa from a tertiary referral hospital of India. Further, in this investigation an effort was made to assess whether different components of MexAB-OprM operon expresses in the same manner and the extent of contributions of those components in meropenem resistance in its natural host (P. aeruginosa) and in a heterologous host (E. coli). Out of 83 meropenem nonsusceptible isolates, 22 isolates were found to possess efflux pump activity phenotypically. Modified hodge test and multiplex PCR confirmed the absence of carbapenemase genes in those isolates. All of them were of multidrug resistant phenotype and were resistant to all the carbepenem drug tested. MexAB-OprM efflux pump was found to be overexpressed in all the study isolates. It could be observed that single dose exposure meropenem could give rise to trivial increase in transcription of mexA gene. Different constructs of MexAB-OprM (mexR-mexA-mexB-OprM; mexA-mexB-OprM; mexA-mexB) could be expressed in both its natural (P. aeruginosa PAO1) and heterologous host (E. coli JM107) but transcription level of mexA gene varied in both the hosts before and after single dose exposure of meropenem. Different components of the operon failed to enhance meropenem resistance in E. coli JM107 and P. aeruginosa PAO1. This study could prove that MexAB-OprM efflux pump can significantly contribute to meropenem resistance in hospital isolates of P. aeruginosa where an acquired resistant mechanism is absent. Thus, equal importance should be given for diagnosis of intrinsic resistance mechanism so as to minimize treatment failure. As meropenem could not enhance mexA transcriptions significantly, there might be a possibility that the increase in expression of efflux pump genes does not mediated by single antibiotic but rather by a combination of antipseudomonal drugs which are used during treatments. Early detection of efflux genes will help in selection of proper therapeutic options.

Ethnomedicinal plants used by traditional healers of North Tripura district, Tripura, North East India.

ETHNOPHARMACOLOGICAL RELEVANCE: Information about ethnomedicinal plants used by traditional healers in Tripura, India is very much limited. As there is rapid erosion of traditional knowledge in the state, needs has arisen to document the diversity of medicinal plants, their preparation and associated diseases. AIM OF THE STUDY: Attempts have been made to explore the herbal medicines used by the traditional healers belonging to the various communities in North Tripura district of Tripura, India and document the associated traditional knowledge on the utilisation of medicinal plants. MATERIALS AND METHODS: The study was based on ethnomedicinal field survey covering a period of 1 year from February 2012 to February 2013. The ethnomedicinal information was collected by using semi-structured questionnaires from different healers and knowledge holders. Collected data were analysed through informant consensus factor, Index of Specialisation and Relative frequency of citation to determine culturally significant plants. RESULTS: A total of 75 species of plants under 68 genera belonging to 43 families were collected during the study for the treatment of 15 disease categories. Leaves were the most frequently used plant parts and most of the medicines were prepared in the form of extract and administered orally. FIC values of the present study indicated that there was a high agreement in the use of plants in the treatment of digestive system disorders and respiratory system disorders among the healers. Plants having high ISu are Justicia adhatoda, Pajanelia longifolia, Catharanthus roseus etc. CONCLUSION: The present study highlighted certain species having higher priority indices for further phytochemical investigation. Counselling of traditional health practitioners should be taken into consideration in order to smooth continuation and extension of traditional medical knowledge and practice for ensuring safe and effective therapy.

Antidiabetic plants used among the ethnic communities of Unakoti district of Tripura, India.

ETHNOPHARMACOLOGICAL RELEVANCE: A large group of ethnic communities living in Unakoti district of Tripura, India is still dependent on traditional herbal remedies for treatment of diabetes. Valuable information collected from these communities in the present investigation is important in maintaining their indigenous knowledge of folklore medicine. METHODS: Systematic and extensive field surveys were conducted during 2011-2013 among the ethnic inhabitants of Unokati district, Tripura, India covering all the seasons to collect information on their traditional herbal medication system for treatment of diabetes. Obtained data were analysed through fidelity level (FL), use value (UV) and relative frequency of citation (RFC) to authenticate the uniqueness of the species being used for diabetes treatment. RESULTS: In this current study a total of 39 medicinal plant species belonging to 37 genera and 28 families were presented, used by the traditional healers of Unakoti district, Tripura, India for diabetes treatment. FL, UV and RFC values of collected plants for the selected study area ranges between 06% and 100%, 0.07% and 2.64% and 0.02% and 0.51% respectively. Out of 39 collected plants, 11, 5 and 3 plant species have showed significant (<50%) FL, UV and RFC values respectively. CONCLUSION: Like many other ethnic communities of the world, inhabitants of Unakoti district depend on a traditional medication system to treat diabetes. Documented floras are locally available and need proper further pharmacological validation to endorse their traditional use in a modern health care system. This will help in the development of effective herbal antidiabetic medicines in near future.

Indigenous knowledge of medicinal plants used by the Reang tribe of Tripura state of India.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditional remedies used for the treatment of various ailments are considered to be very important in the primary health care of Reang people living in Tripura state of Northeast India. Novel information gathered from the present investigation is important in preserving folk indigenous knowledge of Reang tribe. METHODS: Systematic and exhaustive field surveys were conducted during 2003 to 2004 in Reang inhabited areas of Tripura state of Northeast India covering all the seasons, to gather information on medicinal herbs used by them in the treatment of various ailments. Information was collected from 55 traditional herbalists of different age through structured questionnaires and personal observations made during the field visit. The data obtained was analyzed through informant consensus factor (FIC) to determine the homogeneity of informant's knowledge on medicinal plants also the fidelity level (FL) to authenticate the uniqueness of a species to treat a particular ailment. RESULTS: In the present study a total of 125 medicinal plants species belonging to 116 genera and 59 families were presented, used for treating 42 different ailments. The major plant parts used are leaves and most of the remedies are suggested to take orally. The greatest parts of plants used for curing various ailments were found locally. The consensus analysis revealed that the fever and gastro-intestinal diseases have the highest informant consensus factor FIC of 0.79 followed by the dermatological problems (FIC 0.78). It is equal (FIC 0.77) for both general health problems and inflammation and pain while urinogenital problems showed relatively low levels of consensus (FIC 0.63). The level of informants' consent was high for most ailment categories indicating greater homogeneity among informants. In the present study we analyzed the disease categories to highlight some of the important plant species in terms of Fidelity level. Greater parts of the plant species achieve highest fidelity level, while only 4% acquire lower FL. The species with high citation and informant concurrence value are reasonably significant. Cyathea, a rare tree fern used for major cuts or wounds for immediate blood coagulation. Extensive local application may threaten the species if not judiciously managed. CONCLUSION: The traditional pharmacopoeia of the Reang ethnic group incorporates a myriad of diverse flora available locally. Traditional knowledge of the remedies is passed down through oral traditions without any written document. This traditional knowledge is however, currently threatened mainly due to acculturation and deforestation. Therefore, documenting medicinal plants and associated indigenous knowledge can be used as a basis for developing management plans for conservation and sustainable use of medicinal plants of the study area. In addition, findings of this study can be used as an ethnopharmacological basis for selecting plants for future phytochemical and pharmaceutical studies.

Neuroprotective potential of silymarin against CNS disorders: insight into the pathways and molecular mechanisms of action.

Silymarin, a C25 containing flavonoid from the plant Silybum marianum, has been the gold standard drug to treat liver disorders associated with alcohol consumption, acute and chronic viral hepatitis, and toxin-induced hepatic failures since its discovery in 1960. Apart from the hepatoprotective nature, which is mainly due to its antioxidant and tissue regenerative properties, Silymarin has recently been reported to be a putative neuroprotective agent against many neurologic diseases including Alzheimer's and Parkinson's diseases, and cerebral ischemia. Although the underlying neuroprotective mechanism of Silymarin is believed to be due to its capacity to inhibit oxidative stress in the brain, it also confers additional advantages by influencing pathways such as ß-amyloid aggregation, inflammatory mechanisms, cellular apoptotic machinery, and estrogenic receptor mediation. In this review, we have elucidated the possible neuroprotective effects of Silymarin and the underlying molecular events, and suggested future courses of action for its acceptance as a CNS drug for the treatment of neurodegenerative diseases.

Male contraceptive efficacy of Ricinus communis L. extract.

ETHNOPHARMACOLOGICAL RELEVANCE: Ricinus communis L. (Rc), of Euphorbiaceae family is a widespread plant in tropical regions and it is used in traditional medicines as an antifertility agent in India and different parts of the world. AIM OF THE STUDY: The aim of the present study is to revalidate the ethnobotanical knowledge by evaluating the activity of only crude stem bark extracts of Rc. In this study, effects of extracts on male contraceptive efficacy were experimented in vitro with human sperm sample. The work is based on primordial and contemporary therapeutic uses of this plant. MATERIALS AND METHODS: In this study, dose of petroleum ether extract, ethyl acetate extract, acetone extract and lyophilised aqueous extract of Rc were added to fresh human semen in 1:1 volumetric ratio. As the aqueous extract showed a promising result in 1:1 ratio, therefore, the Hypo-osmotic swelling test (HOS), Nuclear chromatin decondensation test (NCD) and Acrosomal status and function test (AFT) were also carried out with the aqueous extract of Rc. RESULTS: The sperm immobilisation effects of the extract appeared immediately in a dose-dependent manner when the samples were treated with four different extracts of this plant. At a concentration of 100mg/mL, 100% (p<0.001 and p<0.05) sperms lost their progressive motility. At a concentration of 300 mg/mL, 100% (p<0.001 and p<0.05) became immotile when treated with aqueous extract. There was 88% (p<0.001 and p<0.05) morphological deformities in sperm sample due the effect of aqueous extract when they were tested for HOS and 91% (p<0.05) sperms behaved against NCD as compared to control group. Also there was a distinct decline (p<0.05) in AFT with increase in dosage concentration. CONCLUSION: The findings of the study revealed that aqueous stem bark extract of the plant showed dose dependent loss of sperm motility by influencing the morphological deformation, blockage in nuclear envelope and distinct declination in acrosomal status of spermatozoa. This research, thus, opens up scope for future exploration of bark of the plant as commercial source of new male contraceptive.