An alkaloid enriched fraction from Murraya koenigii (L.) Spreng. Leaves ameliorate HFD-induced obesity and metabolic complexities in C57BL/6J mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Murraya koenigii commonly known as curry leaf, is traditionally used in India to manage various ailments including diabetes mellitus. Curry leaves are well documented in Indian Ayurvedic system of medicine for beneficial effects in skin eruptions, dysentery, emesis, poisonous bites and bruises. The anti-hyperglycemic and anti-hyperlipidemic effects of curry leaf extracts have been demonstrated through several in vitro and in vivo experiments previously. AIM OF THE STUDY: To prepare an alkaloid enriched fraction (AEF) from M. koenigii and its evaluation on i) in vitro adipogenesis process and ii) in vivo high fat diet-induced obesity in C57BL/6J mice. MATERIALS AND METHODS: MKME and AEF were prepared from M. koenigii leaves. The four carbazole alkaloids (bioactive markers) isolated from AEF were quantitatively determined in the leaves by RP-HPLC method. MKME and AEF were studied for anti-obesogenic activity in adipocytes in vitro and in HFD-induced C57BL/6J obese mice in vivo. At the termination of the in vivo study, lipid profile, hepatic and renal injury and glucose levels were analyzed in the blood samples. Animal tissues were examined histopathologically to determine any signs of damage. Repeated dose oral toxicity study for 28 days on Sprague-Dawley rats was also performed to determine the safety profile of AEF. RESULTS: Both MKME and AEF displayed anti-obesogenic activity at 25 µg/ml concentration in vitro and showed 54.06 ± 3.86% and 37.46 ± 3.17% lipid accumulation, respectively compared to control. Further, supplementation of AEF and MKME in HFD-fed C57BL/6J mice helped in controlling weight gain, improved dyslipidemia and glucose intolerance significantly. AEF showed better anti-obesity activity than MKME both in vitro and in vivo study. Repeated administration of AEF up to 1 g/kg dose for 28 days showed no pathological tissue damage. Both MKME and AEF were standardized using a simple and validated RP-HPLC method. CONCLUSION: Present study was aimed at preparation of a novel alkaloid-enriched fraction from methanolic extract of M. koenigii leaf and its evaluation for anti-diabesity effect. Our results demonstrated AEF to be a promising plant-based therapy for ameliorating obesity and related metabolic complications in HFD-fed C57BL/6J mice.

Wound-healing effect of topical nanoemulsion-loaded cream and gel formulations of Hippophae rhamnoides L. (sea buckthorn) fruit oil and their acute dermal toxicity study on female SD rats.

OBJECTIVE: The objective of this study was to evaluate the efficacy and safety of topical nanoemulsion (NE)-loaded cream and gel formulations of Hippophae rhamnoides L. (sea buckthorn [SBT]) fruit oil for wound healing. MATERIALS AND METHODS: The NE-loaded cream and gel formulations of H. rhamnoides L. (SBT) fruit oil (IPHRFH) were prepared and evaluated for their wound-healing activity on female Sprague-Dawley (SD) rats. They were further divided into groups (seven) and the wound-healing activity was determined by measuring the area of the wound on the wounding day and on the 0th, 4th, 8th, and 10th days. The acute dermal toxicity of the formulations was assessed by observing the erythema, edema, and body weight (BW) of the rats. RESULTS: The topical NE cream and gel formulations of H. rhamnoides L. (SBT) fruit oil showed significant wound-healing activity in female SD rats. The cream formulation of IPHRFH showed 78.96%, the gel showed 72.59% wound contraction on the 8th day, whereas the positive control soframycin (1% w/w framycetin) had 62.29% wound contraction on the 8th day. The formulations also showed a good acute dermal toxicity profile with no changes significantly affecting BW and dermal alterations. CONCLUSIONS: The results of this study indicate that topical NE-loaded cream and gel formulation of H. rhamnoides L. (SBT) fruit oil are safe and effective for wound healing. The formulations showed no signs of acute dermal toxicity in female SD rats.

Pyrrole-based inhibitors of RND-type efflux pumps reverse antibiotic resistance and display anti-virulence potential.

Efflux pumps of the resistance-nodulation-cell division (RND) superfamily, particularly the AcrAB-TolC, and MexAB-OprM, besides mediating intrinsic and acquired resistance, also intervene in bacterial pathogenicity. Inhibitors of such pumps could restore the activities of antibiotics and curb bacterial virulence. Here, we identify pyrrole-based compounds that boost antibiotic activity in Escherichia coli and Pseudomonas aeruginosa by inhibiting their archetype RND transporters. Molecular docking and biophysical studies revealed that the EPIs bind to AcrB. The identified efflux pump inhibitors (EPIs) inhibit the efflux of fluorescent probes, attenuate persister formation, extend post-antibiotic effect, and diminish resistant mutant development. The bacterial membranes remained intact upon exposure to the EPIs. EPIs also possess an anti-pathogenic potential and attenuate P. aeruginosa virulence in vivo. The intracellular invasion of E. coli and P. aeruginosa inside the macrophages was hampered upon treatment with the lead EPI. The excellent efficacy of the EPI-antibiotic combination was evidenced in animal lung infection and sepsis protection models. These findings indicate that EPIs discovered herein with negligible toxicity are potential antibiotic adjuvants to address life-threatening Gram-negative bacterial infections.

Exploring the efficacy of ethnomedicinal plants of Himalayan region against the malaria parasite.

ETHNOPHARMACOLOGICAL RELEVANCE: Plasmodium falciparum multi-drug resistant (MDR) strains are a great challenge to global health care. This predicament implies the urgent need to discover novel antimalarial drugs candidate from alternative natural sources. The Himalaya constitute a rich repository of medicinal plants which have been used traditionally in the folklore medicine since ages and having no scientific evidence for their activity. Crambe kotschyana Boiss. and Eremurus himalaicus Baker are used for their antipyretic and hepatoprotective properties in Kinnaur district of Himachal Pradesh, India. AIM OF THE STUDY: This study would investigate the antiplasmodial efficacy of C. kotschyana and E. himalaicus extracts, their fractions and active components using in vitro, in vivo and in silico approaches to provide a scientific insight into their activity. METHODS: The methanol extracts of C. kotschyana (CKME) and E. himalaicus (EHME) were prepared by maceration followed by fractionation using ethyl acetate. The isolation of flavonoid glycosides isorhamnetin-3, 7-di-O-glucoside from C. kotschyana and luteolin-6-C-glucoside (isoorientin) from E. himalaicus was carried out by antiplasmodial activity-guided isolation. In vitro antimalarial activity was assessed by WHO method while in vitro cytotoxicity was ascertained employing the MTT assay. Molecular docking and molecular dynamics simulation were performed using the Glide module of Schrödinger Software and Gromacs-2022 software package respectively. In vivo curative activity was assessed by Ryley and Peters method. RESULTS: The methanol extracts of both the plants illustrated the best antiplasmodial activity followed by the ethyl acetate fractions. Iso-orientin (IC50 6.49 µg/ml) and Isorhamnetin-3,7-di-O-glucoside (IC50 9.22 µg/ml) illustrated considerable in vitro activity even against P. falciparum resistant strain. Extracts/fractions as well as the isolated compounds were found to be non-toxic with CC50 > 640 µg/ml. Molecular docking studies were performed with these 2 O-glucosides against four malaria targets to understand the binding pose of these molecules and the results suggested that these molecules have selectivity for lactate dehydrogenase enzyme. CKME and EHME exhibited curative activity in vivo along with increase in Mean Survival Time of mice. CONCLUSION: The research delineated the scientific evidence that both the therapeutic herbs possessed antimalarial activity and notably, bioactive compounds responsible to exhibit the antimalarial activity have been isolated, identified and characterized. Further studies are underway to assess the antiplasmodial efficacy of isolated compounds alone and in combination with standard antimalarials.

Efflux pump inhibitory potential of indole derivatives as an arsenal against norA over-expressing Staphylococcus aureus.

NorA, an extensively studied efflux pump in Staphylococcus aureus, has been connected to fluoroquinolone, antiseptic, and disinfection resistance. Several studies have also emphasized how efflux pumps, including NorA, function as the first line of defense of S. aureus against antibiotics. In this study, we have screened some chemically synthesized indole derivatives for their activity as efflux pump inhibitors (EPIs). The derivative SMJ-5 was found to be a potent NorA efflux pump inhibitor among the screened indole derivatives, owing to increased ethidium bromide and norfloxacin accumulation in norA over-expressing S. aureus. The combination of SMJ-5 and ciprofloxacin demonstrated the eradication of S. aureus biofilm and prolonged the post-antibiotic effect more than ciprofloxacin alone. SMJ-5 was able to inhibit staphyloxanthin virulence. In in vitro time-kill trials and in vivo efficacy investigations, the combination enhanced the bactericidal activity of ciprofloxacin against S. aureus. Additionally, reverse transcription PCR results revealed that SMJ-5 also inhibits the NorA efflux pump indirectly at the transcriptional level. IMPORTANCE The NorA efflux pump is the most effective resistance mechanism in S. aureus. The clinical importance of NorA efflux pumps is demonstrated by the expression of pump genes in S. aureus strains in response to fluoroquinolones and biocides. Along with the repercussions of decreased fluoroquinolone sensitivity, increasing expression of efflux pump genes by their substrate necessitates the importance of efflux pump inhibitors. Reserpine and verapamil are clinically used to treat ailments and have proven NorA inhibitors, but, unfortunately, the concentration needed for these drugs to inhibit the pump is not safe in clinical settings. In the current study, we have screened some indole derivatives, and among them, SMJ-5 was reported to potentiate norfloxacin and ciprofloxacin at their sub-inhibitory concentration by inhibiting the norA gene transcriptionally. Here we highlight the promising points of this study, which could serve as a model to design a therapeutic EPI candidate against norA over-expressing S. aureus.

Efficacy of Young Cinnamomum zeylanicum Blume Bark on Hyperglycemia and PTPase Activity in Type 2 Diabetes.

Diabetes is a major public health concern and natural easy-going remedies are being searched. Since Cinnamomum zeylanicum Blume has a low coumarin concentration and possible insulin-enhancing properties, it is preferred over all other cinnamon species. Although similar research has been done on humans, there have been very few studies on this particular species, and none among South Asians. Moreover, no human trial that properly described their intervening agent (C. zeylanicum) and checked its efficacy at the molecular level along with clinical variables was conducted. Therefore, the current research aimed to explore the effects of C. zeylanicum on the glycemic index, lipid profile, and expression of the protein tyrosine phosphatase 1 B (PTP1B) enzyme in the peripheral blood mononuclear cells (PBMC) in type 2 diabetes. We examined the presence of bioactive compounds in young C. zeylanicum bark (Alba grade) from native Sri Lanka using gas chromatography-mass spectrometry, high-performance thin-layer chromatography, and thin-layer chromatography before introducing it in the clinical study where trans-Cinnamaldehyde was found to be a major chemical constituent (>60%). Then, from January 2020 to March 2022, a randomized double-blinded placebo-controlled trial was carried out in the Diabetic Clinic at AIIMS Rishikesh. A total of 154 diabetic patients were enrolled and were taken either cinnamon or placebo capsules (1.5 g/day) for 120 days on an empty stomach with warm water along with their conventional treatment. Reduction in fasting blood glucose levels in the cinnamon group was found -35.50% (95% CI, -173 to 58.4), whereas in the placebo group change was 5.00% (95% CI, -165 to 224). For glycosylated hemoglobin, it differed -0.85% (95% CI, -8.2 to 1.6) in the cinnamon group compared to the placebo where it was found 0.15% (95% CI, -6.1 to 5.5). PTP1B expression in PBMC was determined from pre- and post-trial blood samples using the Western Blot, and significant inhibition was also observed (p=0.039). The study result depicts, C. zeylanicum is emerging as a beneficial plant for type 2 diabetes in Northern India and could be used as an adjunctive treatment rather than as a standalone managerial remedy.

Quantitative analysis of tiliroside and other flavonoid glycosides in Hippophae salicifolia D. Don leaves by HPLC-PDA.

A new HPLC-PDA method was developed and validated for simultaneous determination of five phenolic compounds (trans-and cis- isomers of tiliroside, quercetin-3-O-ß-D-glucoside, ellagic acid, kaempferol-3-O-ß-D-glucoside and isorhamnetin-3-O-glucoside) in the leaves of Hippophae salicifolia D. Don. Of the five compounds, three (tiliroside, quercetin-3-O-ß-D-glucoside and ellagic acid) were isolated and characterised by spectroscopy techniques. The developed HPLC method provided a selective, sensitive and rapid analysis with good linearity (r2> 0.999), accuracy and precision. Also, the leaves of H. salicifolia were extracted by three different extraction techniques viz. reflux, microwave and ultrasound. Methanolic extracts prepared by reflux method showed the highest content of all the five compounds.

Evaluation of the in vitro and in vivo anti-inflammatory activity of Gymnosporia montana (Roth). Benth leaves.

ETHNO-PHARMACOLOGICAL RELEVANCE: Gymnosporia montana (Roth) Benth an herbaceous shrub used in Indian traditional medicine their leaves decoction was used as mouthwash to get relieve from toothache, hence it is also known as Dantakashta in Sanskrit language which means the plant used for tooth problems. Traditionally the leaves juice used to alleviate inflammation and in some parts of India like Saurashtra in Gujarat, leaves were chewed as a folklore cure for Jaundice and in Bhandra region Karnataka, leaves extract mixed with cow milk used for jaundice. Hepatoprotective activity for G. montana leaves was well reported however, its use for inflammation and toothache are still not studied to investigate active phytoconstituents responsible for anti-inflammatory activity. AIM OF THE STUDY: The present study aimed at bioactivity guided isolation of G. montana leaves extracts using inhibition of pro-inflammatory mediators such as nitric oxide (NO), tumor necrosis factor (TNF-α), and interleukins (IL-1ß and IL-6) in RAW 264.7 cells in vitro assay to yield bioactive phytoconstituents. MATERIALS AND METHODS: The n-hexane, ethyl acetate and methanol extracts prepared from G. montana leaves were evaluated for cell viability using MTT assay. The effect of extracts to inhibit the pro-inflammatory mediators like NO, TNF-α, IL-1ß and IL-6 in RAW 264.7 macrophages was measured by enzyme-linked immunosorbent assay (ELISA). The quantitative analysis of the isolated phytoconstituents was performed using quantitative Nuclear Magnetic Resonance (qNMR). RESULTS: The n-hexane, ethyl acetate, and methanol extracts of G. montana leaves exhibited cell viability in the range of 97.43-84.88% at 50 µg/mL concentration in RAW 264.7 macrophages. In-vitro evaluation of extracts showed that n-hexane extract was most effective in inhibiting NO, TNF-α, IL-1ß and IL-6 inflammatory mediators at 50 µg/mL in lipopolysaccharides (LPS) stimulated RAW 264.7 cells. Further n-hexane extract, its fraction GMHA3 and ß-amyrin exhibited significant anti-inflammatory activity at 100, 50 and 30 mg/kg per oral, respectively in carrageenan-induced rat paw edema. The quantitative analysis by qNMR revealed ß-amyrin as a major compound in the n-hexane extract. CONCLUSIONS: In vitro and in vivo bioassay results suggested that G. montana n-hexane extract, its fraction GMHA3 and ß-amyrin exhibits significant anti-inflammatory activity proves the traditional uses of G. montana leaves. The reported activity of ß-amyrin for periodontitis provides evidence of profound the use of G. montana leaves for toothache and anti-inflammatory activity.

Design, Synthesis, Molecular Modelling, and Biological Evaluation of Oleanolic Acid-Arylidene Derivatives as Potential Anti-Inflammatory Agents.

INTRODUCTION: Oleanolic acid, a pentacyclic triterpenic acid, is widely distributed in medicinal plants and is the most commonly studied triterpene for various biological activities, including anti-allergic, anti-cancer, and anti-inflammatory. METHODS: The present study was carried out to synthesize arylidene derivatives of oleanolic acid at the C-2 position by Claisen Schmidt condensation to develop more effective anti-inflammatory agents. The derivatives were screened for anti-inflammatory activity by scrutinizing NO production inhibition in RAW 264.7 cells induced by LPS and their cytotoxicity. The potential candidates were further screened for inhibition of LPS-induced interleukin (IL-6) and tumour necrosis factor-alpha (TNF-α) production in RAW 264.7 cells. RESULTS: The results of in vitro studies revealed that derivatives 3d, 3e, 3L, and 3o are comparable to that of the oleanolic acid on the inhibition of TNF-α and IL-6 release. However, derivative 3L was identified as the most potent inhibitor of IL-6 (77.2%) and TNF-α (75.4%) when compared to parent compound, and compounds 3a (77.18%), 3d (71.5%), and 3e (68.8%) showed potent inhibition of NO than oleanolic acid (65.22%) at 10µM. Besides, from docking score and Cyscore analysis analogs (3e, 3L, 3n) showed greater affinity towards TNF-α and IL-1ß than dexamethasone. CONCLUSION: Herein, we report a series of 15 new arylidene derivatives of oleanolic acid by Claisen Schmidt condensation reaction. All the compounds synthesized were screened for their anti-inflammatory activity against NO, TNF-α and IL-6. From the data, it was evident that most of the compounds exhibited better anti-inflammatory activity.

Natural Product Inhibitors of Cyclooxygenase (COX) Enzyme: A Review on Current Status and Future Perspectives.

BACKGROUND: Several clinically used COX-1 and COX-2 inhibitor drugs were reported to possess severe side effects like GI ulcers and cardiovascular disturbances, respectively. Natural products being structurally diverse always attracted the attention of chemists/ medicinal chemists as a potential source of lead molecules in the drug discovery process. COX-2 inhibitory natural products also possess potential cancer chemopreventive property against various cancers including that of colon, breast and prostate. METHODS: Various in vitro, in vivo and in silico standardized methods were used to evaluate COX inhibition property of different secondary metabolites isolated from plant, microbial and marine origin. RESULTS: We had earlier reported a detailed account of natural product inhibitors of COX reported during 1995-2005, in 2006. In the proposed review, we report 158 natural product inhibitors of COX during 2006 to 2019 belonging to various secondary metabolite classes such as alkaloids, terpenoids, polyphenols as flavonoids, chromones, coumarins, lignans, anthraquinones, naphthalenes, curcuminoids, diarylheptanoids and miscellaneous compounds of plant and marine origin. Further Structure Activity Relationship (SAR) studies of possible leads are also included in the article. CONCLUSION: COX inhibitors served as a potential source of lead molecules for the discovery and development of anti-inflammatory drugs. Compilation of natural product and semisynthetic inhibitors of COX may serve as valuable information to the researchers who are looking for possible lead molecules from a natural source to conduct further preclinical and clinical studies.

Origanum vulgare L.: In vitro Assessment of Cytotoxicity, Molecular Docking Studies, Antioxidant and Anti-inflammatory Activity in LPS Stimulated RAW 264.7 Cells.

BACKGROUND: Inflammation involves a dynamic network that is highly regulated by signals that initiate the inflammation process as well as signals that downregulate it. However, an imbalance between the two leads to tissue damage. Throughout the world, inflammatory disease becomes common in the aging society. The drugs which are used clinically have serious side effects. Natural products or compounds derived from natural products show diversity in structure and play an important role in drug discovery and development. OBJECTIVE: Oreganum Vulgare is used in traditional medicine for various ailments including respiratory and rheumatic disorders, severe cold, suppression of tumors. The current study aims to evaluate the anti-inflammatory potential by evaluating various in vitro parameters. METHODS: Inflammation-induced in macrophages via LPS is the most accepted model for evaluating the antiinflammatory activity of various plant extracts and lead compounds. RESULTS: The extracts (OVEE, OVEAF) as well as the isolated compound(OVRA)of Oreganum Vulgare inhibit the pro-inflammatory cytokines (IL-6 and TNF-α) and NO without affecting cell viability. CONCLUSION: Our study established that the leaf extracts of Oreganum vulgare L. exhibit anti-inflammatory activity and thus confirm its importance in traditional medicine.

Natural Anti-inflammatory Compounds as Drug Candidates in Alzheimer's Disease.

Alzheimer's disease (AD) is a chronic neurodegenerative brain disorder characterized by memory impairment, dementia, and oxidative stress in elderly people. Currently, only a few drugs are available in the market with various adverse effects. Therefore, to develop new drugs with protective action against the disease, research is turning to the identification of plant products as a remedy. Natural compounds with anti-inflammatory activity could be good candidates for developing effective therapeutic strategies. Phytochemicals, including Curcumin, Resveratrol, Quercetin, Huperzine-A, Rosmarinic acid, genistein, obovatol, and Oxyresvertarol, were reported molecules for the treatment of AD. Several alkaloids, such as galantamine, oridonin, glaucocalyxin B, tetrandrine, berberine and anatabine, have been shown anti-inflammatory effects in AD models in vitro as well as in-vivo. In conclusion, natural products from plants represent interesting candidates for the treatment of AD. This review highlights the potential of specific compounds from natural products along with their synthetic derivatives to counteract AD in the CNS.

Is Cinnamon Efficacious for Glycaemic Control in Type-2 Diabetes Mellitus?

Diabetes is on the rise, and has become a major public health issue. In view of limitations of available glucose lowering therapy, there is a need to explore and develop natural remedies with anti-diabetic properties. Spices such as cinnamon, cloves, bay leaves, and turmeric display insulin-enhancing activity in vitro. Cinnamon or Dalchini is popularly use as a spice for its fragrance and flavour in wide variety of traditional foods. Among various types of cinnamon, C. zeylanicum is well known as effective substitute for diabetes. Cinnamaldehyde is one of the major constituents (65-80%) of bark oil extracted from C. Zeylonicum which seems to reduce plasma blood glucose concentration more effectively when it is compared with metformin. It enhances the expression of proteins involved in glucose transport, insulin signalling, and regulates dyslipidaemia. This review describes the basic and clinical pharmacology of cinnamon.

Synthesis, biological evaluation and computational studies of acrylohydrazide derivatives as potential Staphylococcus aureus NorA efflux pump inhibitors.

The NorA efflux pump decreases the intracellular concentration of fluoroquinolones (ciprofloxacin, norfloxacin) by effluxing them from Staphylococcus aureus cells. The synthesis of novel acrylohydrazide derivatives was achieved using well-known reactions and were characterized by various spectroscopy techniques. The synthesized 50 compounds were evaluated for the NorA efflux pump inhibition activity against S. aureus SA-1199B (norA++) and K1758 (norA-) strains. The study provided two most active compounds viz. 19 and 52. Compound 19 was found to be most active in potentiating effect of norfloxacin and also it showed enhanced uptake, efflux inhibition in ethidium bromide assay. Further compound 19 also enhanced post antibiotic effect and reduced mutation prevention concentration of norfloxacin. The homology modeling study was performed to elucidate three-dimensional structure of NorA. Docking studies of potent molecules were done to find the binding affinity and interaction with active site residues. Further, all the tested compounds exhibited good ADME and drug-likeness properties in- silico. Based on the in-silico studies and detailed in vitro studies, acrylohydrazides derivatives may be considered as potential NorA EPI candidates.

Role of environmental pollutants in Alzheimer's disease: a review.

Neurodegenerative disorders are commonly erratic influenced by various factors including lifestyle, environmental, and genetic factors. In recent observations, it has been hypothesized that exposure to various environmental factors enhances the risk of Alzheimer's disease (AD). The exact etiology of Alzheimer's disease is still unclear; however, the contribution of environmental factors in the pathology of AD is widely acknowledged. Based on the available literature, the review aims to culminate in the prospective correlation between the various environmental factors and AD. The prolonged exposure to the various well-known environmental factors including heavy metals, air pollutants (particulate matter), pesticides, nanoparticles containing metals, industrial chemicals results in accelerating the progression of AD. Common mechanisms have been documented in the field of environmental contaminants for enhancing amyloid-ß (Aß) peptide along with tau phosphorylation, resulting in the initiation of senile plaques and neurofibrillary tangles, which results in the death of neurons. This review offers a compilation of available data to support the long-suspected correlation between environmental risk factors and AD pathology. Graphical abstract .

Pyrazole-coumarin and pyrazole-quinoline chalcones as potential antitubercular agents.

Pyrazole, coumarin, and quinoline are medicinally important moieties. In this study, two series of novel pyrazole-coumarin chalcones and pyrazole-quinoline chalcones were synthesized using multiple-step reactions. All the synthesized compounds were well characterized using different spectroscopic techniques including 1 H and 13 C nuclear magnetic resonance, high-resolution mass spectroscopy, and electrospray ionization-mass spectrometry. The compounds were evaluated for their antitubercular activity against the Mycobacterium tuberculosis H37Rv strain using the microplate Alamar Blue assay, and the minimal inhibitory concentrations (MIC) of the compounds were determined. Among the 32 tested compounds, compounds 3e, 3u, and 7h showed an MIC value of 3.125 µg/ml, and they were found to be nontoxic. Molecular docking studies of the compounds with the enzyme DprE1 revealed the probable mechanism of action. The chalcone derivatives exhibited binding affinity values between -7.047 and -9.353 kcal/mol. ADME parameters were predicted using the QikProp module of the Schrödinger software, and these compounds exhibited good pharmacological and oral absorption properties.

MsrA Efflux Pump Inhibitory Activity of Piper cubeba L.f. and its Phytoconstituents against Staphylococcus aureus RN4220.

MsrA, an efflux pump belonging to ATP-binding cassette (ABC) transporter family that conferred resistance to macrolides, was detected in Staphylococcus aureus strains. Herein, we report the isolation of phytoconstituents from Piper cubeba fruit methanol extract and investigated their efflux pump inhibitory potential against S. aureus MsrA pump. Four isolated compounds, viz. pellitorine, sesamin, piperic acid and tetrahydropiperine studied in combination with erythromycin in S. aureus RN4220, exhibited 2-8-fold reduction in minimum inhibitory concentration (MIC) of erythromycin. Pellitorine and sesamin decreased MIC of erythromycin by 8-fold. The real-time fluorometry-based efflux and accumulation studies of ethidium bromide (EtBr) on S. aureus RN4220 in the presence of these compounds showed reduced efflux and enhanced uptake, thus indicating inhibition of the efflux pump. Pellitorine showed significant post-antibiotic effect of erythromycin. The results revealed that the primary mechanism of action of these compounds involves steady ATP production impairment.

Microbe-Derived Indole Metabolite Demonstrates Potent Multidrug Efflux Pump Inhibition in Staphylococcus aureus.

Efflux pumps are always at the forefront of bacterial multidrug resistance and account for the failure of antibiotics. The present study explored the potential of 2-(2-Aminophenyl) indole (RP2), an efflux pump inhibitor (EPI) isolated from the soil bacterium, to overcome the efflux-mediated resistance in Staphylococcus aureus. The RP2/antibiotic combination was tested against efflux pump over-expressed S. aureus strains. The compound was further examined for the ethidium bromide (EtBr) uptake and efflux inhibition assay (a hallmark of EPI functionality) and cytoplasmic membrane depolarization. The safety profile of RP2 was investigated using in vitro cytotoxicity assay and Ca2+ channel inhibitory effect. The in vivo efficacy of RP2 was studied in an animal model in combination with ciprofloxacin. RP2 exhibited the synergistic activity with several antibiotics in efflux pump over-expressed strains of S. aureus. In the mechanistic experiments, RP2 increased the accumulation of EtBr, and demonstrated the inhibition of its efflux. The antibiotic-EPI combinations resulted in extended post antibiotic effects as well as a decrease in mutation prevention concentration of antibiotics. Additionally, the in silico docking studies suggested the binding of RP2 to the active site of modeled structure of NorA efflux pump. The compound displayed low mammalian cytotoxicity and had no Ca2+ channel inhibitory effect. In ex vivo experiments, RP2 reduced the intracellular invasion of S. aureus in macrophages. Furthermore, the RP2/ciprofloxacin combination demonstrated remarkable efficacy in a murine thigh infection model. In conclusion, RP2 represents a promising candidate as bacterial EPI, which can be used in the form of a novel therapeutic regimen along with existing and upcoming antibiotics, for the eradication of S. aureus infections.

Pseudomonas koreensis Recovered From Raw Yak Milk Synthesizes a ß-Carboline Derivative With Antimicrobial Properties.

Natural evolution in microbes exposed to antibiotics causes inevitable selection of resistant mutants. This turns out to be a vicious cycle which requires the continuous discovery of new and effective antibiotics. For the last six decades, we have been relying on semisynthetic derivatives of natural products discovered in "Golden Era" from microbes, especially Streptomyces sp. Low success rates of rational drug-design sparked a resurgence in the invention of novel natural products or scaffolds from untapped or uncommon microbial niches. Therefore, in this study, we examined the microbial diversity inhabiting the yak milk for their ability to produce antimicrobial compounds. We prepared the crude fermentation extracts of fifty isolates from yak milk and screened them against indicator strains for the inhibitory activity. Later, with the aid of gel filtration chromatography followed by reversed-phase HPLC, we isolated one antimicrobial compound Y5-P1 from the strain Y5 (Pseudomonas koreensis) which showed bioactivity against Gram-positive and Gram-negative bacteria. The compound was chemically characterized using HRMS, FTIR, and NMR spectroscopy and identified as 1-acetyl-9H-ß-carboline-3-carboxylic acid. It showed minimum inhibitory activity (MIC) in the range of 62.5-250 µg /ml. The cytotoxicity results revealed that IC50 against two mammalian cell lines i.e., HepG2 and HEK293T was 500 and 750 µg/ml, respectively. This is the first report on the production of this derivative of ß-carboline by the microorganism. Also, the study enlightens the importance of microbes residing in uncommon environments or unexplored habitats in the discovery of a diverse array of natural products which could be designed further as drug candidates against highly resistant pathogens.

Therapeutic potential of seabuckthorn: a patent review (2000-2018).

Introduction: Seabuckthorn (SBT) has received worldwide attention for therapeutic, nutraceutical and cosmetic purposes. It is used for the treatment of a number of diseases. Hundreds of commercial products containing SBT are available in the market. Areas covered: This review article covers patents on the therapeutic potential of SBT and its chemical constituents. The therapeutic areas covered in this review include cancer, cardiovascular, diabetes, inflammation, anti-oxidant, and anti-microbial. The patents were searched through Sci-finder, Espacenet, Google Patent, and US Patent. Expert opinion: Plant-based drugs have played an important role in the modern drug industry. Since ancient times, SBT has been used to cure several ailments. SBT has emerged as an important plant, which has been investigated for numerous pharmacological properties and shown to be beneficial in a number of therapeutic areas. Several clinical trials have demonstrated the therapeutic potential of SBT for the treatment of many diseases including cardiovascular, inflammation, diabetes, platelet inhibition, etc. There is huge potential for developing standardized herbal products from different parts of SBT.