Isolation Of Bioactive Compounds Research Articles

Molecular Docking Studies and Anti-Alzheimer’s Potential of Isolated Compounds from Tinospora cordifolia

Inhibition of acetylcholinesterase (AChE) is a promising strategy for the management of Alzheimer’s disease (AD). Prolyl endopeptidase (PEP) is a post-proline cleaving enzyme that plays an important role in learning and memory. This study explore the AChE and PEP inhibitory activities of compounds from T. cordifolia. Their affinity for different binding sites in silico was also evaluated. Ellman’s and β-naphtyl acetate-fast blue salt (NA-FB) assay methods were used to determine the cholinesterase inhibitory activity. PEP inhibition was determined by colorimetric assay according to Yoshimoto. Isolation of bioactive compounds was done by different chromatographic methods and structures established using spectroscopy. Molecular docking was carried out using MOE software suite modeled structures based on the coordinates of PDB ID: 3IVM and 10CE. The ethyl acetate fraction had the best AChE inhibition with an IC50 value of 1.4574 ± 0.47 mg/mL at 5 mg/mL. Nine compounds identified as β-sitosterol, tinosporide, 8-hydroxycolumbin, oxoglaucine, corydine, liriodenine, N-formylanonaine, palmatine, 1-octacosanol were isolated from different fractions with oxoglaucine being reported for the first time in the genus Tinospora. Oxoglaucine, liriodenine and N-formylanonaine demonstrated good AChE inhibitory activity with IC50 values of 0.8033 ± 0.09 mg/mL, 0.8076 ± 0.07 mg/mL and 0.8190 ± 0.06 mg/mL at 1 mg/mL respectively. Oxoglaucine and corydine at 1 mM inhibited prolyl endopeptidase with IC50 values of 0.7802 ± 3.1 mM and 0.7884 ± 3.17 mM respectively. Molecular docking revealed hydrophobic, hydrogen bonding, and Pi-stacking interactions between the ligands and the active site of enzymes. Compounds from Tinospora cordifolia are a possible lead for the development of drugs that may be useful in the management of AD.

Metabolite Profiling of Aquilaria malaccensis Leaf Extract Using Liquid Chromatography-Q-TOF-Mass Spectrometry and Investigation of Its Potential Antilipoxygenase Activity In-Vitro

The Aquilaria malaccensis species of the genus Aquilaria is an abundant source of agarwood resin and many bioactive phytochemicals. Recent data regarding the chemical constituents and biological activities of Aquilaria leaves led us to attempt to qualitatively profile the metabolites of Aquilaria malaccensis leaves from a healthy, noninoculated tree through phytochemical screening, GC-MS, and LC/Q-TOF-MS. The present work is also the first to report the antilipoxygenase activity of A. malaccensis leaves from healthy noninoculated tree and investigate its toxicity on oral mucosal cells. A total of 53 compounds were tentatively identified in the extract, some of which have been described in literature as exhibiting anti-inflammatory activity. A number of compounds were identified for the first time in the extract of A. malaccensis leaf, including quercetin, quercetin-O-hexoside, kaempferol-O-dirhamnoside, isorhamnetin-O-hexoside, syringetin-O-hexoside, myricetin, tetrahydroxyflavanone, hesperetin, sissotrin, and lupeol. The antilipoxygenase assay was used to determine the lipoxygenase (LOX) inhibitory potential of the extract, while a WST-1 assay was conducted to investigate the effect of the extract on oral epithelial cells (OEC). The extract implied moderate anti-LOX activity with IC50 value of 71.6 µg/mL. Meanwhile, the cell viability of OEC ranged between 92.55% (10 µg/mL)–76.06% ± (100 µg/mL) upon treatment, indicating some potential toxicity risks. The results attained encourage future studies of the isolation of bioactive compounds from Aquilaria malaccensis leaves, as well as further investigation on the anti-inflammatory mechanisms and toxicity associated with their use.

Phytochemical Screening and GC-MS analysis of Pavonia Zeylanica

The current paper is focused to screen phytochemicals, and GC-MS from the leaves of P. zeylanica. This study deals with screening of phytochemicals, isolation of bioactive compound(s) and characterization partial purified and purified compounds (Silica gel Column Chromatography coupled with TLC) with the aid of GC-MS.

Antimicrobial Evaluation of Latex and TLC Fractions from the Leaves of Aloe adigratana Reynolds.

Background The highest prevalence and emergence of microbial infections coupled with the threat of antimicrobial resistance constitute a global concern, which entails searching for novel antimicrobial agents. Medicinal plants are among the major sources of medicines for novel drug discovery. Aloe adigratana is one of the endemic Aloe species in Ethiopia where the leaf latex of the plant is traditionally used for the treatment of various pathogenic conditions such as wound, dandruff, malaria, and diabetes. In spite of such claims, there was no scientific study done so far. The aim of the current study was, therefore, to evaluate the antimicrobial effect of leaf latex of A. adigratana and its thin layer chromatography (TLC) fractions. Methods Thin layer chromatography (TLC) separation was employed for isolation of bioactive compounds. Agar well diffusion and microdilution assay method were used to evaluate the antimicrobial actions of the leaf latex and TLC fractions against six bacterial strains and four Candida species of reference and clinical isolate microbial strains. Results Three major fractions, AA01, AA02, and AA03, were identified by TLC. Among the tested microbial strains, the reference strain of Staphylococcus aureus ATCC 29213 (MIC = 0.06 mg/mL) and clinical Candida krusei 242/18 (MIC = 0.14 mg/mL) exhibited higher susceptibility towards AA02, while reference strains of Klebsiella pneumoniae ATCC 700603 (MIC = 0.19 mg/mL) revealed the highest susceptibility towards AA01. The leaf latex displayed the highest activity against Staphylococcus aureus ATCC 29213 and clinical Candida krusei 242/18 with a MIC value of 0.19 mg/mL. Conclusion The leaf latex and TLC fractions were found to be active against the tested bacterial and Candida species. Therefore, this finding supports the traditional claim of Aloe adigratana and the need for characterization of the TLC fractions to provide as lead compounds for further comprehensive antibacterial and antifungal activities.

UPLC-MS/MS characterization of phenolic constituents in fennel seed extracts (Foeniculum vulgare Mill.)

AbstractReports in the recent literature indicate that consumption of phytochemicals (e.g. plant polyphenols) has been associated with a wide range of health benefits. Fennel (Foeniculum vulgare Mill.) is common Mediterranean plant that has been widely used as medicinal and aromatic herb. Numerous studies reported the use of fennel extracts (plant or seed) due to its diversity of phenolic compounds to whom inhibitory effects against several diseases are prescribed. Hence, phenolic compounds isolated from fennel are of the great interest for the use in food, chemical and pharmaceutical industries.In order to obtain the highest quality of the fennel extracts, the selection of an effective extraction procedure is required. Nowadays, innovative extraction techniques have been introduced for isolation of bioactive compounds from plant material, among which pressurized liquid extraction (PLE) was reported as automated extraction procedure that combines effects of elevated temperature and pressure to increase the efficiency of the extraction process. Improved efficiency is also achieved by selecting the right solvent and by optimizing processing conditions (temperature, static time, cycle number).Thus, PLE was applied for the extraction of phenolic compounds from fennel seeds. The effects of exhaustive extraction (acetone followed by methanol) as well as extraction temperatures (75 and 100 °C), static time (5 and 10 min) and cycle number (1,2,3) on the phenolic compounds concentrations were evaluated. A total of 27 phenolic compounds were identified and characterized by UPLC-ESI-MS/MS whereas 6 different categories are distinguished: (1) simple phenolic acid derivatives, (2) hydroxycinnamoylquinic acid derivatives, (3) flavonoid diglycosides, (4) flavonoid O-rhamnoglucosides, (5) flavonoid glucuronides and (6) flavonoid glycosides. Phenolic compounds were identified by comparing retention time and m/z values obtained by MS and MS/MS with the mass spectra from corresponding standards whereas the quantification was made on the basis of their peak areas and comparison with calibration curve obtained with the corresponding standards. Obtained results indicated that hydroxycinnamoylquinic acid derivatives (10 compounds) and flavonoid glucuronides (3 compounds) were found as the most abundant phenolics in acetone and methanol extracts, respectively. Statistical analysis showed that optimized PLE conditions for the most effective extraction of phenolic compounds were as follows: 100 °C/10 min/3 cycles for acetone and 100 °C/5 min/3 cycles for methanol extracts. In conclusion, PLE might be considered as a rapid and effective extraction procedure that could be useful in production of fennel seeds extracts.

Antimicrobial, Cytotoxic, and Antioxidant Potential of a Novel Flavone "6,7,4'-Trimethyl Flavone" Isolated from Wulfenia amherstiana.

Wulfenia amherstiana belongs to the Scrophulariaceae family and various plants of this family are known for their biological activities. The present study was focused on the isolation of bioactive compounds including a novel flavone 6,7,4′-trimethyl flavone (TMF) along with three known flavonoids such as quercetin, rutin, and a steroid β-sitosterol which were isolated from the ethanolic extract of W. amherstiana (Himalayan Wulfenia) through column chromatography and purified by using HPLC. Their structures were identified and elucidated through electron ionization mass spectroscopy (EIMS), 1DNMR (1H-NMR and 13C-NMR), and 2DNMR (COSY, HMQC, and HMBC) spectroscopy. The antimicrobial activities of this novel compound were evaluated through agar well diffusion method, while antioxidant and cytotoxic activities were assessed through 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging assay and brine shrimp lethality assay, respectively. The NMR data revealed that TMF is a novel compound. TMF showed potential antibacterial and antifungal activities against Staphylococcus aureus (MIC = 128 μg/ml) and Candida albicans (MIC = 128 μg/ml). The cytotoxic potential of TMF was determined from brine shrimp lethality assay with LD50 of 127.01 μg/ml. The free-radical scavenging potential of TMF at various concentrations implicated its strong antioxidant activity in vitro. The results revealed that TMF demonstrated substantial antimicrobial activity against S. aureus and C. albicans, strong antioxidant activity, and moderately cytotoxic activity.

Inhibition of fungal endo-1,3-B-glucanase by phenols isolated from Turnera diffusa: an alternative for conventional antifungals

La enzima endo-(1,3)-B-glucanasa tiene una función fisiológica en los procesos morfogenéticos durante el desarrollo y diferenciación en algunos hongos. Adicionalmente, esta enzima ha sido implicada durante el ataque de hongo en la interacción hongo fitopatógeno-planta. Por lo que la endo-(1,3)-B-glucanasa fúngica, se ha utilizado como sitio-objetivo para la búsqueda dirigida de antifúngicos. Utilizando un aislamiento bio-dirigido de compuestos bioactivos, se aislaron dos ácidos fenólicos de tallos de <em>Turnera diffusa</em>, los cuales inhiben la actividad de endo-(1,3)-B-glucanasa fúngica. Los compuestos identificados como apigenina y luteolina inhiben la actividad del enzima en 90 y 60%, respectivamente. Consistente con el efecto de la inhibición de la enzima fúngica, la apigenina a concentracion milimolar, fue capaz de inhibir completamente la germinación de esporas de <em>Botrytis cinerea</em>. Con estos resultados se infiere que la acción antifúngica de la apigenina es una consecuencia de su capacidad para inhibir la enzima endo-(1,3)-B-glucanasa.

Characterization of in-vitro antioxidant, cytotoxic, thrombolytic and membrane stabilizing potential of different extracts of Cheilanthes tenuifolia and Stigmasterol isolation from n-hexane extract

BackgroundCheilanthes tenuifolia, a member of the Pteridaceae family, is an evergreen and small fern could be abundant of bioactive compounds. The present study was designed to investigate its many therapeutic properties and isolation of bioactive compounds from extracts of Cheilanthes tenuifolia.MethodsThe dried coarse plant powder was extracted with methanol and dried with rotary evaporator. The extract was further partitioned according to the increasing polarity: N-hexane < chloroform < ethyl-acetate < methanol by modified Kupchan method. Then each extract fractions were investigated for their pharmacologic properties. Compounds were isolated from n-hexane fraction through column chromatography, followed by TLC and structure was determined by analysis of sample using 1H-NMR and matched with published phytochemistry report.ResultsMethanol fraction of Cheilanthes tenuifolia showed highest amount of total phenol content (11.32 ± 0.28 mg/gm GAE) followed by chloroform fraction (9.71 ± 0.31 mg/gm GAE) > N-hexane fraction (6.69 ± 0.67 mg/gm GAE) > ethyl acetate fraction (5.36 ± 0.54 mg/gm GAE). The methanol fraction of Cheilanthes tenuifolia possessed highest amount (7.11 ± 0.52 mg/gm QE) of total flavonoid content. Our present study indicates that methanol extract was most potent (IC50 = 9.926 μg/ml) inhibitor of DPPH free radicals. In brine shrimp lethality bio assay, all the extracts showed dose dependent increment of mortality and chloroform extract was found most cytotoxic (LC50 = 34.493 μg/ml) compared to other plant extracts. The chloroform fraction of Cheilanthes tenuifolia was most potent in terms of thrombolytic activity. A compound was isolated (CT-2) using column chromatography followed by TCL and PTLC (35% pet ether in CHCl3) and analyzed by 1H-NMR. The structure of stigmasterol was confirmed by comparing the 1H-NMR data with previously published phytochemistry report.ConclusionCheilanthes tenuifolia could be a potential candidate for bioactive compounds and further studies on isolation and characterization of its bioactive compounds are highly required.

Isolation of bioactive compounds from Bergenia ciliata (haw.) Sternb rhizome and their antioxidant and anticholinesterase activities

BackgroundBergenia ciliata is a medicinal plant used for the treatment of diarrhea, vomiting, fever, cough, diabetes, cancer, pulmonary disorders and wound healing.MethodsIn this study, Bergenia ciliata crude extract, subfractions, and isolated compounds were evaluated for their antioxidant and anticholinesterase potential. The free radical scavenging capacities of the extracts determined using DPPH and ABTS assays. The anticholinesterase potentials were determined using acetylcholine esterase and butyryl choline esterase enzymes. To determine the phytochemical composition, the extracts were subjected to HPLC analysis and silica gel column isolation. Based on HPLC fingerprinting results, the ethyl acetate fraction was found to have more bioactive compounds and was therefore subjected to silica gel column isolation. As a result, three compounds; pyrogallol, rutin, and morin were isolated in the pure state. The structures of the isolated compounds were elucidated using spectroscopic techniques like 1H-NMR, IR and UV-Visible.ResultsThe crude extract showed maximum anticholinesterase (acetylcholinesterase = 90.22 ± 1.15% and butyrylcholinesterase = 88.22 ± 0.71%) and free radical scavenging (87.37 ± 2.45 and 83.50 ± 0.70% respectively against DPPH and ABTS radicals) potentials. The total phenolic contents (expressed as equivalent of gallic acid; mgGAE/g) were higher in ethyl acetate fraction (80.96 ± 1.74) followed by crude extract (70.65 ± 0.86) while the flavonoid contents (expressed as quercetin equivalent; mgQE/g) and were higher in crude extract (88.40 ± 1.12) followed by n-butanol fraction (60.10 ± 1.86). The isolated bioactive compounds pyrogallol, rutin, and morin were found active against ABTS and DPPH free radicals. Amongst them, pyrogallol was more active against both free radicals. Reasonable anticholinesterase activities were recorded for pyrogallol against selected enzymes.ConclusionThe extracts and isolated compounds showed antioxidant and acetylcholinesterase inhibitory potentials. It was concluded that this plant could be helpful in the treatment of oxidative stress and neurological disorders if used in the form of extracts.

Antioxidant activity guided isolation of a coumarin compound from Ipomoea pes-caprea (Convolvulaceae) leaves acetone extract and its biological and molecular docking studies

IntroductionSeveral modern drugs have been derived from plants, which contain numerous biologically active metabolites. Ipomoea pes-caprea (F: Convolvulaceae) is used in traditional medicine to treat several ailments. The present study aimed to investigate the pharmacological properties and the biological applications of Ipomoea pes-caprea. MethodsThe phytochemical screening analysis, estimation of phytoconstituents, antioxidant, and antibacterial activities were conducted. Based on the results of preliminary studies the bioactive extract was subjected to GC–MS analysis, and activity guided isolation of bioactive compound obtained. The isolated active principle was subjected to various spectral analyses such as: UV, FT-IR, LC–MS and 1H, 13C, DEPT, HMBC, and HSQC NMR to elucidate the structure and analyze its biological potential. ResultsThe results of phytochemical screening indicated the presence of various phytochemicals in Ipomoea pes-caprea extracts. The acetone extract possesses a significantly high amount of metabolites with antibacterial as well as antioxidant capacity, with low IC50 values. Results of acetone extract GC–MS analysis revealed that the presence of several bioactive compounds where 2-phenyl-4H-chromen-4-one was predominant. Antioxidant activity guided isolation of acetone extract resulted in the isolation of a coumarin compound (5,7-dihydroxy-4-phenyl-2H-chromen-2-one) and the structure was confirmed using various spectral studies. The isolated 5,7-dihydroxy-4-phenyl-2H-chromen-2-one exhibited significant antioxidant, antimicrobial and antiproliferative activities. In addition, the molecular docking study revealed that the isolated coumarin is a good inhibitor of the angiopoietin-2. ConclusionsThe present study concludes that the isolated compound (5,7-dihydroxy-4-phenyl-2H-chromen-2-one) may harbor significant health benefits and it may serve as a good molecular template in pharmacology for the development of new drugs.

Metabolomic profiling of Zanthoxylum species: Identification of anti-cholinesterase alkaloids candidates

The isolation of bioactive compounds from natural sources is a key step in drug discovery and development, however, this procedure is usually expensive and difficult due to the complexity and the limited amounts of the metabolites in the extracts. Thus, rational or targeting isolations are becoming more popular to reduce the bottlenecks in bioactive natural products research. In this study, we used a LC-MS-based metabolomic approach and biochemometric statistical tools (PCA and OPLS-DA) to identify potential anti-cholinesterase alkaloids predictors in Zanthoxylum genus (Rutaceae). For this purpose, 41 alkaloid extracts from nine Colombian Zanthoxylum species were screened by UHPLC-UV-HRMS and inhibitory activity against Acetylcholinesterase (AChE) and Butyrylcholinesterase (BChE). Based on the screening results, a multivariate statistical analysis (MVA) and selection of anti-cholinesterase candidates were performed using the S-plot from the OPLS-DA model. The supervised analysis (OPLS-DA) paring the anti-cholinesterase screening and LC-HRMS data showed at least 11 ChE inhibition markers which could have contributed in the differentiation of active and inactive extracts. The predictors were tentatively identified by comparing chromatographic retention times (Rt) and accurate mass and MS2 fragmentation patterns. In general, the inhibition markers correspond to four types of isoquinoline alkaloids: tetrahydroprotoberberines, protoberberines, dihydrobenzophenanthridines and benzophenanthridines. The most active extracts from Z. schreberi and Z. monophylum showed the highest presence of berberine and chelerythrine, previously reported as cholinesterase inhibitors. Thus, to validate the results of the OPLS-DA model, three alkaloids from the bark of Z. schreberi (identified as berberine, chelerythrine and columbamine) were bio-directed isolated, and all of them showed strong inhibition against both enzymes. These findings support our statistical models and contribute to the rational search of anticholinesterase alkaloids. Therefore, LC-MS-based metabolomic approach combined with chemometric statistical analysis are shown as useful tools for the isolation of targeted bioactive natural products, contributing to improve the research and development stages of lead compounds.

QUALITATIVE PHYTOCHEMICAL SCREENING AND FTIR SPECTROSCOPIC ANALYSIS OF GREWIA TILIFOLIA (VAHL) LEAF EXTRACTS

Objective: The present study aim is to analyse the phytochemicals present in Grewia tilifolia (Vahl) leaf extracts by using Qualitative phytochemical analysis, Fourier-transform infrared spectroscopy (FTIR).&#x0D; Methods: The leaf extracts were prepared using eight different solvents. The phytochemical analysis Fourier transform infrared spectroscopy (FT-IR) analysis were performed using standard methods.&#x0D; Results: The FTIR spectroscopic studies revealed different characteristic peak values with various functional groups present in the compounds of respective extracts. The FT-IR analysis shows the presence of different functional groups such as alcohols, phenols, alkanes, carboxylic acids, aldehydes, ketones, alkenes, primary amines, aromatics, esters, ethers, alkyl halides and aliphatic amine compounds, which showed major compounds present in the leaf extracts. The present study generated the FTIR spectrum profile for the medicinally important plant Grewia tilifolia.&#x0D; Conclusion: The present study provides evediences that different extracts of Grewia tilifolia leaf is useful to cure many serious diseases which remained still problematic and for further isolation of bioactive compounds from the plant which could be of interest for the development of the new drug.

Natural trypanocidal product produced by endophytic fungi through co-culturing.

Endophytic fungi live inside vegetal tissues without causing damage to the host plant and may provide lead compounds for drug discovery. The co-culture of two or more endophytic fungi can trigger silent gene clusters, which could lead to the isolation of bioactive compounds. In this study, two endophytic strains isolated from Handroanthus impetiginosus leaves, identified as Talaromyces purpurogenus H4 and Phanerochaete sp. H2, were grown in mixed and axenic cultures. The meroterpenoid austin was detected only in the extracts from the mixed culture. Once isolated, austin displayed very interesting trypanocidal activity, with an IC50 value of 36.6 ± 1.2μg/mL against Trypanosoma cruzi in the epimastigote form. The results obtained highlight the importance of the co-culturing of endophytic fungi to obtain natural bioactive products. The findings also enhance our understanding of the ecological relationships between endophytic fungi.

Corrigendum: A Multi-Mode Bioactive Agent Isolated From Ficus microcarpa L. Fill. With Therapeutic Potential for Type 2 Diabetes Mellitus.

[This corrects the article DOI: 10.3389/fphar.2018.01376.].

Bioactive Compounds Isolated from Marine-Derived Microbes in China: 2009-2018.

This review outlines the research that was carried out regarding the isolation of bioactive compounds from marine-derived bacteria and fungi by China-based research groups from 2009–2018, with 897 publications being surveyed. Endophytic organisms featured heavily, with endophytes from mangroves, marine invertebrates, and marine algae making up more than 60% of the microbial strains investigated. There was also a strong focus on fungi as a source of active compounds, with 80% of publications focusing on this area. The rapid increase in the number of publications in the field is perhaps most notable, which have increased more than sevenfold over the past decade, and suggests that China-based researchers will play a major role in marine microbial natural products drug discovery in years to come.

Rare actinobacteria: a potential source of bioactive polyketides and peptides.

Polyketides and peptides obtained from actinobacteria are important therapeutic compounds which include front line antibiotics and anticancer drugs. Many screening programs are directed towards isolation of bioactive compounds from these organisms but the chances of finding novel antimicrobial leads among common actinobacteria are fast dwindling. As a result, the focus has shifted to the members of less exploited genera of rare actinobacteria. Three isolates, MMS8, MMS16 and KCR3 found to be potent polyketide and peptide producers were identified by 16S rRNA gene sequencing and their sequences deposited in the GenBank under the accession numbers MG407702, MG372012 and MG430204 respectively. MMS8 identified as Micromonospora auratinigra, yielded one potent compound determined to be chloroanthraquinone with an minimum inhibitory concentration (MIC) of 8µg/ml against Bacillus subtilis and an IC50 value of 10µg/ml and 4μg/ml against HeLa and IMR cell lines respectively. This is the first report of the production of chloroanthraquinone by M. auratinigra. MMS16, identified as a member of the family Micromonosporaceae, yielded a potent compound MMS16B analyzed to be a novel bafilomycin analogue. The MIC of the compound was found to be 7μg/ml against B.subtilis and IC50 value against HeLa and IMR was observed to be 9μg/ml and 14μg/ml respectively. MMS16B was also found to exhibit anti-quorum sensing (AQS) activity at sublethal concentrations. KCR3 identified as Kocuria kristinae yielded a novel antimicrobial peptide with antibacterial, antifungal and AQS activity. To the best of our knowledge, no antimicrobial activity has ever been reported from K. kristinae.

Microalgae for High-Value Products Towards Human Health and Nutrition.

Microalgae represent a potential source of renewable nutrition and there is growing interest in algae-based dietary supplements in the form of whole biomass, e.g., Chlorella and Arthrospira, or purified extracts containing omega-3 fatty acids and carotenoids. The commercial production of bioactive compounds from microalgae is currently challenged by the biorefinery process. This review focuses on the biochemical composition of microalgae, the complexities of mass cultivation, as well as potential therapeutic applications. The advantages of open and closed growth systems are discussed, including common problems encountered with large-scale growth systems. Several methods are used for the purification and isolation of bioactive compounds, and many products from microalgae have shown potential as antioxidants and treatments for hypertension, among other health conditions. However, there are many unknown algal metabolites and potential impurities that could cause harm, so more research is needed to characterize strains of interest, improve overall operation, and generate safe, functional products.

Bioprospecting of Halotolerant Bacillus subtilis: A Study depicting its Potential Antimicrobial Activity against Clinically Important Pathogens

Objectives: The current study focuses on characterization and isolation of bioactive compounds from a marine halophilic bacterium and testing its antimicrobial potentiality against clinically important pathogens like Proteus mirabilis, Salmonella typhi A, Salmonella typhi B, Pseudomonas aeruginosa and Klebsiella pneumoniae. The study also portraits presence of possible bioactive compounds responsible for such antimicrobial activity through Gas Chromatography-Mass Spectrometry (GC-MS). Methodology: Surface water samples were collected from Kovalam beach at Thiruvananthapuram, Kerala state, a South Indian coast of Indian peninsula and were screened for potential bacteria. Morphological, biochemical and molecular profiling were performed to identify and isolate the bacterium of interest. Antibiogram studies were conducted to understand pathogenic trends in the isolate. Culture supernatant of the test bacterium was screened against clinically important pathogens. Further, crude extract of the culture supernatant was subject to GC-MS analysis. Findings: Morphological, biochemical and molecular profiling of the isolate revealed the organism to be Bacillus subtilis. The culture supernatant had significant activity against clinically important pathogens. GC-MS analysis revealed possible antimicrobial compound to be (Pyrrolo [1, 2-a] pyrazine-1, 4-dione). Novelty: The study has significant importance as it depicts antimicrobial activity of halophiles against potent clinical pathogens. Keywords: Antibiogram Profiling, Bioactive Compounds, Gas Chromatography-Mass Spectrometry (GC-MS), Marine Halophiles, Molecular Profiling

Capsaicin and gingerol analogues inhibit the growth of efflux-multidrug resistant bacteria and R-plasmids conjugal transfer

Ethnopharmacological importanceCapsicum and ginger are used widely in human diets and in folklore medicines. Chemically, gingerol is a relative of capsaicin and both classes of compounds are notable for their spiciness and characteristic pungent aroma. Previous studies have demonstrated that these compounds contain antimicrobial compounds with robust pharmacological importance. AimThe present study evaluated the in vitro antibacterial activities of capsaicinoids and gingerols against a panel of clinical MRSA strains and their inhibitory effect on the conjugal transfer of R-plasmids harboured in E. coli. Materials and methodsCrude methanol extract of C. annum was fractionated using solid phase extraction (SPE) and screened for R-plasmid transfer inhibition: TP114, PUB 307, PKM 101, R6K and R7K. The bio-guided assay led to the isolation of bioactive compounds with strong R-plasmid transfer inhibition. The compounds were identified using Nuclear Magnetic resonance (NMR) and Mass spectroscopy (MS). Capsaicin analogues nonivamide, 6-gingerol, 6-shogaol, capsaicin and dihydrocapsaicin were screened for antimicrobial activity against a panel of methicillin-resistant Staphylococcus aureus (MRSA) and Gram-negative bacteria strains using microdilution method while the plasmid transfer inhibition assay of the compounds was determined by broth mating method. ResultsThe bioactive fraction Ca-11 showed good inhibition rates (8.57–25.52%) against three R-plasmids PUB307, PKM 101, TP114 followed by the crude extract of C. annum (8.59%) respectively leading to the bioassay-guided isolation of capsaicin and dihydrocapsaicin as the bioactive principles. The antiplasmid effect of pure capsaicin and dihydrocapsaicin were broad and within active ranges (5.03–31.76%) against the various antibiotic resistance-conferring plasmids including R6K, R7K. Capsaicin, 6-gingerol and 6-shogaol had good broad antibacterial activity with MIC values ranging from 8 to 256 mg/L against effluxing MRSA strains SA1199B (NorA), XU212 (TetK) and RN4220 (MsrA). While they exhibited moderate antibacterial activity (128–512 mg/L) against the Gram-negative bacteria. The effect of 6-gingerol, 6-shogaol and nonivamide on the plasmids were very active on PKM 101 (6.24–22.16%), PUB 307 (1.22–45.63%) and TP114 (0.1–7.19%) comparative to the positive control plumbagin (5.70–31.76%). ConclusionThese results are suggestive that the R-plasmids could possess substrate for capsaicinoids-like compounds and for their ability to inhibit the plasmid conjugation processes. Plant natural products possess the potential value of antibacterial and mechanistic antiplasmid activity as demonstrated by the compounds and should be evaluated in developing antimicrobial leads to novel mechanism against multidrug-resistant bacteria.

Diminished Activity of Larval Midgut Transaminases and Phosphatases in Helicoverpa armigera Hübner (Lepidoptera) Induced by Dietary Stem Extracts of Thevetia neriifolia

Helicoverpa armigera Hubner (Noctuidae) is a common crop pest causing extensive loss of crop yields despite several efforts and diverse measures taken. As utilization of synthetic pesticides in the fields have caused ecological disturbances and lethal effects on humans and organisms; present studies explore Thevetia neriifolia (Apocynaceae), a widely used ornamental plant, against H. armigera as an alternate control measure. The study investigates the dietary effects of hexane and methanol extracts of T. neriifolia stems (HSE, MSE) on the activity of midgut enzymes of H. armigera, the alterations in which could hamper its growth and development. Different concentrations of the stem extracts, ranging from 0.001% to 0.02%, were incorporated in the diet of early IV instars of H. armigera. Effect of each extract was assessed by estimating the activity of four midgut enzymes; alanine aminotransaminase (ALT), aspartate aminotransaminase (AST), acid phosphatase (ACP) and alkaline phosphatase (ALP) of cotton boll worm. Investigations showed that dietary stem extracts resulted in significant and dose-dependent reduced activity of all the enzymes. The percent inhibition of the enzymatic activity was higher with dietary MSE of T. neriifolia as compared to the hexane stem extract. Also, the enzyme inhibition effects of extracts were more pronounced on phosphatases in comparison to transaminases. Larval feeding with T. neriifolia MSE diminished ALT activity by 26.95% to 49.79% and AST activity by 11.02% to 56.53%, whereas the ACP and ALP activity decreased by 44.65% to 87.61% and 21.97% to 85.97%, respectively. On the other hand, HSE inhibited ALT activity by 29.43% to 41.67% and AST activity by just 2.72% to 47.08%. However, a respective reduction of 14.58% to 78.44% and 32.73% to 78.07% was noticed in ACP and ALP activity with dietary HSE. The GC-MS analysis of the stem hexane and methanol extracts of T. neriifolia reveals the presence of 39 and 30 phyto-chemicals, respectively. Investigations showed the possible use of T. neriifolia extracts as a growth regulatory agent against H. armigera. Identification and isolation of bioactive compounds require further investigations.