TLC Bioautographic Assay Research Articles

Neuroprotective Properties of Oleanolic Acid-Computational-Driven Molecular Research Combined with In Vitro and In Vivo Experiments.

Oleanolic acid (OA), as a ubiquitous compound in the plant kingdom, is studied for both its neuroprotective and neurotoxic properties. The mechanism of acetylcholinesterase (AChE) inhibitory potential of OA is investigated using molecular dynamic simulations (MD) and docking as well as biomimetic tests. Moreover, the in vitro SH-SY5Y human neuroblastoma cells and the in vivo zebrafish model were used. The inhibitory potential towards the AChE enzyme is examined using the TLC-bioautography assay (the IC50 value is 9.22 μM). The CH-π interactions between the central fragment of the ligand molecule and the aromatic cluster created by the His440, Phe288, Phe290, Phe330, Phe331, Tyr121, Tyr334, Trp84, and Trp279 side chains are observed. The results of the in vitro tests using the SH-SY5Y cells indicate that the viability rate is reduced to 71.5%, 61%, and 43% at the concentrations of 100 µg/mL, 300 µg/mL, and 1000 µg/mL, respectively, after 48 h of incubation, whereas cytotoxicity against the tested cell line with the IC50 value is 714.32 ± 32.40 µg/mL. The in vivo tests on the zebrafish prove that there is no difference between the control and experimental groups regarding the mortality rate and morphology (p > 0.05).

Phytochemical Screening of Nyctanthes arbor-tristis Plant Extracts and Their Antioxidant and Antibacterial Activity Analysis.

Nyctanthes arbor-tristis, alias "Vishnu Parijat," is a medicinal plant used to treat various inflammation-associated ailments and to combat innumerable infections in the traditional system of medicine. In the present study, we collected the samples of N. arbor-tristis from the lower Himalayan region of Uttarakhand, India, and carried out their molecular identification through DNA barcoding. To examine the antioxidant and antibacterial activities, we prepared the ethanolic and aqueous extracts (from flowers and leaves) and performed their phytochemical analysis by using different qualitative and quantitative approaches. The phytoextracts showed marked antioxidant potential, as revealed by a comprehensive set of assays. The ethanolic leaf extract showed marked antioxidant potential towards DPPH, ABTS, and NO scavenging (IC50 = 30.75 ± 0.006, 30.83 ± 0.002, and 51.23 ± 0.009 μg/mL, respectively). We used TLC-bioautography assay to characterize different antioxidant constituents (based on their Rf values) in the chromatograms ran under different mobile phases. For one of the prominent antioxidant spots in TLC bioautography, GC-MS analysis identified cis-9-hexadecenal and n-hexadecanoic acid as the major constituents. Furthermore, in antibacterial study, the ethanolic leaf extract showed marked activity against Aeromonas salmonicida (113.40 mg/mL of extract was equivalent to 100 μg/mL of kanamycin). In contrast, the ethanolic flower extract showed considerable antibacterial activity against Pseudomonas aeruginosa (125.85 mg/mL of extract ≡100 μg/mL of kanamycin). This study presents the phylogenetic account and unravels the antioxidant-related properties and antibacterial potential of N. arbor-tristis.

Evaluation of hydromethanolic extract and aglycone fraction of Actiniopteris semiflabellata for antioxidant activity

Actiniopteris semiflabellata Pic-Ser grows in Yemen and is used by the local population for wounds and burns. The goal of the current study was to assess the Actiniopteris semiflabellata's chemical composition and antioxidant activity. Phenols, flavonoids, triterpenes and sterols were identified in the hydromethanolic extract and in the aglycone fraction, while carbohydrates were only found in the hydromethanolic extract. In the hydromethanolic extract and the aglycone fraction, the total phenolic content was evaluated as 17.73 mg/g and 7.22 mg/g respectively, while the total flavonoid content was 11.21 mg/g and 4.13 respectively. Studied extract and fraction exhibited antioxidant activity by TLC bioautography and DPPH radical scavenging activity assay. The IC50 values for the hydromethanolic extract and the aglycone fraction were 79.64 and 148.60 µg/ml respectively. These results confirm the traditional use and are useful for further study of this plant, in addition, it may be a good source of natural antioxidants.

In silico screening, TLC bioautography and in vivo studies of Zanthoxylum armatum DC. (Indian Prickly Ash) extract as a potential neuroprotective agent

Zanthoxylum armatum DC., a popular spice, and folklore medicine, is widely distributed throughout the Northeastern region of India and practiced by indigenous tribes as a remedy for digestive and nervous system disorders. The study aimed to assess the neuro-protective potentiality of Zanthoxylum armatum extract through different learning and memory paradigms against scopolamine-induced cognitive impairment. For the isolation of the compounds, coarsely powdered shade-dried fruits were extracted with ethanol by the cold maceration method. In silico studies were performed for the isolated compounds. TLC bioautographic enzyme assay was developed to screen acetylcholinesterase and butyrylcholinesterase inhibition by plant extract using donepezil, a known acetylcholinesterase inhibitor. Memory retention activities of ethanolic extract (100, 200, and 400 mg/kg; p.o.) were determined in-vivo , along with an estimation of whole-brain cholinesterase and antioxidant activity. Chromatographic analysis from chloroform fraction resulted in the isolation of three bio-active phytoconstituents, and structural elucidation identified them as β-sitosterol (ZA-01), Stigmasterol (ZA-02), and Lupeol (ZA-03). In silico molecular docking studies revealed stigmasterol has the minimum binding energy with acetylcholinesterase among all the isolated bioactive. The stability of the protein-ligand complex was found satisfactory after performing molecular dynamics simulation studies. Pre-treatment with extract significantly improved transfer latency in maze tests decreased rat brain acetylcholinesterase activity, and showed antioxidant potentiality against scopolamine-induced memory impairment. The combination of neuroprotective, anticholinesterase, and antioxidant effects shown by Z. armatum extract may be what makes it a nootropic drug. These are good signs for the search for natural nootropics from Z. armatum extract. Even so, more research with extracts and isolated compounds will be needed to make the traditional uses of the plant more scientifically sound. • Zanthoxylum armatum is evaluated for its potential as neuroprotective agent. • β-sitosterol, Stigmasterol and Lupeol were isolated from the plant extract. • In silico molecular docking and molecular dynamics simulations were performed. • TLC bioautography, in vivo animal tests showed good neuroprotective action of Zanthoxylum armatum extract.

Isolation and identification of antioxidative peptides from crocodile meat hydrolysates using silica gel chromatography

Crocodiles are cultured in large numbers in Asia and other places in order to protect wild resources and meet the needs of human life. In this study, crocodile (Crocodylus siamensis) meat proteins were extracted and hydrolyzed into peptides, their antioxidant peptides were isolated and purified by silica gel chromatography and identified by LC/MS. Crocodile meat proteins were optimally extracted with water and hydrolyzed by papain based on the degree of hydrolysis and antioxidant activity. The hydrolysates were fractionated by ultrafiltration into 3 kDa, 3–30 kDa, and ≥ 30 kDa fractions. The 3 kDa fraction showed most antioxidant activity of the hydrolysates. Its active peptides were separated by silica gel column chromatography and purified by silica gel TLC, based on TLC bio-autographic assays of the activity. Four highly active peptides were identified by LC/MS as SSLTIQFVEGQFVDSYDPTIENTFTK, VPPHIY, VAPEEHPVLLTEAPLNPK, and RNGLPGPIGPAG. The identified peptides were synthesized and showed 50% free radical scavenging activities at 1.0 mg/mL, equal or higher to ascorbic acid at 0.5 mg/mL, in both DPPH and ABTS assays. The results indicated that the 3 kDa hydrolyzed peptides of crocodile meat had high antioxidant activity and the active peptides can be effectively separated and purified by silica gel column chromatography and TLC.

Compositional Analysis and Antioxidant Activities of Thymus pubescens Essential Oil from Iran.

The genus Thymus is one of the well-known members of the Lamiaceae, comprising about 215 species. It is a polymorphic genus in this family. Therefore, possible differences in chemical composition among polymorphs may result in differences in their biological activities. This study was designed to specify chemical composition in order to assess antioxidant activities and to characterize active constituents of essential oil of Thymus pubescens. Essential oil was collected by hydrodistillation and was analyzed using GC-MS and GCFID. Antioxidant activities were evaluated by ABTS radical cation scavenging and β-carotene bleaching inhibition methods. Detection and identification of antioxidant components were performed by TLC-bioautography assay using ABTS•+ reagent. GC analyses indicated the presence of 39 components, accounting for 96.64% of total constituents, with thymol (38.67%), γ-terpinene (7.46%), and p-cymene (5.54%) as the main components. The IC50 values for antioxidant activities were equal to 1.15 (1.05 - 1.25) μg/mL and 0.45 (0.33 - 0.62) μg/mL for ABTS•+ scavenging and β-carotene bleaching inhibition tests, respectively. TLC-bioautography of oil resulted in the identification of thymol as the major antioxidant compound. Essential oil exhibited very potent and significant antioxidant activities correlated well with increasing dose in vitro.

ANTIBACTERIAL ACTIVITY OF ROBUSTA COFFEE (Coffea robusta L.) PEEL EXTRACT AGAINST HUMAN PATHOGENIC BACTERIA

Now in these days infectious diseases seriously affect human health and sometimes these infections might become the cause of human mortality. Most of these infectious diseases are caused by bacteria, viruses, and fungi. Although large numbers of antibiotics are available increasing drug resistance in these microorganisms became a serious matter of concern in the scientific community. There is an urgent need for research on alternate natural products that can manage these pathogenic microorganisms without inducing any resistance. The purpose of this study was to determine the antibacterial activity of Robusta coffee (Coffea robusta L.) fruit peel extract against 5 human pathogenic bacteria i.e. Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, and Salmonella thypi NCTC 786. The sample was extracted using the maceration method with methanol as the solvent. The antibacterial activity of fruit peel extract was determined by using the agar diffusion method while the presence of active ingredients was determined by the using TLC-Bioautography assay performed using the mobile phase of n-hexane: ethyl acetate (1 : 3). The results of the study revealed significant antibacterial activity of coffee peel extract against E. coli and B. subtilis with an inhibition zone of 10.15 mm and 10.96 mm, respectively. Furthermore, results of the TLC-Bioautography revealed that the compounds at Rf 0.76 inhibit the growth of E. coli and the compounds at Rf 0.27 inhibit the growth of B. subtilis bacteria. These active spots were suspected to be flavonoid and phenolic compounds, respectively but further confirmation detail study is required in the future.

Molecular profiling and anti-infective potency of endophytic actinomycetes inhabiting Madhuca insignis Radlk., from Western Ghats of India

BackgroundEndophytic actinomycetes are well known for their diverse bioactive entities and considered as an important source for drug development research. ResultsWe isolated and identified four potential endophytic Streptomyces species, i.e., Streptomyces misionensis MI22, Streptomyces roietensis MI24, Streptomyces glaucescens MI29, and Streptomyces sp. MI04 inhabiting Madhuca insignis by its characteristic morphological features and 16S rRNA gene sequence analysis. S. misionensis MI22 exhibits a broad spectrum of anti-microbial activity against methicillin-resistant Staphylococcus aureus (25.00 ± 1.00 mm) followed by Bacillus subtilis (23.66 ± 0.57 mm), Escherichia coli (22.00 ± 0.00 mm), and Candida albicans (18.00 ± 0.00 mm). Minimum inhibitory concentrations of the ethyl acetate fraction of S. misionensis MI22 against test pathogens were ranged from 25 to 100 μg/mL. Indeed, strain MI22 also exhibited significant anti-proliferative activity against HeLa cell line with IC50 value 98 μg/mL and showed no cytotoxicity effect to the normal human embryonic kidney cell line in the MTT assay. The anti-microbial metabolites from strain MI22 were detected at Rf 0.55 as depicted by the inhibition zone on the intensive band in TLC-bioautography assay. ConclusionThe study indicates that, anti-microbial metabolites of these endophytic Streptomyces species, especially S. misionensis MI22 as a prolific source to discover novel bioactive metabolites to combat multidrug-resistant pathogens.

Metabolite Detection and Antibacterial Activity of Fungal Endophytic Extracts Isolated from Brotowali (Tinospora crispa) Plants using TLC-Bioautography Assay

Endophytic fungi may be a potent source of bioactive compounds and have a vast repertoire of diverse metabolites. One source of endophytic fungi host plants is a medicinal plant such as Brotowali or Tinospora crispa. Research corresponding to the antibacterial activity of endophytic fungi extracts isolated from T.crispa taken from several regions in West Java has never been reported yet. While antibacterial methods to evaluate their activity as well as to identify the chemical compounds is a TLC-bioautography assay. This research is aimed to investigate the components of endophytic fungal extracts and their antibacterial activity using the TLC-bioautography assay method. In this study, eighty isolates of endophytic fungi have been successfully isolated from plant tissues of T.crispa from several regions in West Java. Antibacterial activity by using TLC (dot-blot) plates revealed that the fungal extracts could inhibit S. aureus (77 extracts) and E. coli (35 extracts) with inhibition zones ranging from 8-30 mm. The endophytic fungi extracts that showed potent antibacterial activity against Gram-positive bacteria (S.aureus) were sixteen extracts, while nine extracts have good inhibition activity against Gram-negative bacteria (E.coli). Among the fungal extracts that have excellent ability against both Gram-positive and negative was namely TcBt1Bd-10 extract. Based on metabolites analysis using the TLC method, the possibility of the chemical compounds that played a role in antibacterial activity of the extracts, including phenolics, flavonoids, alkaloids, and terpenoids.

In vitro Evaluation of Acetylcholinesterase Inhibitory and Neuroprotective Activity in Commiphora species: A Comparative Study

Introduction: Herbal medicines are widely used in the therapeutic intervention that could delay the onset of Neurodegenerative diseases like, Alzheimer’s disease. Despite intensive advancements in the field of research currently available therapeutic strategies are often limited due to their adverse effects. Hence there is a need for the search for novel compounds for effective medications to treat neurocognitive deficits. Objective: The present study focused on acetylcholinesterase inhibitory and neuroprotective activity of Commiphora species plant for their possible use in Alzheimer’s disease. Methods: Phytochemical screening, TLC bioautographic and colourimetric assay was performed to quantify their acetylcholinesterase inhibitory activity of ethanolic extracts of the Commiphora species. The MTT assay was carried to evaluate the neuroprotective effect against the Aβ-induced cytotoxicity in SHSY5Y cell lines. Results: The bark of Commiphora berryi, leaves of Commiphora caudata and Commiphora pubescens were found abundant in flavonoids, glycosides, steroids and terpenoids. Further, the ethanol extract of Commiphora berryi (65.48% ± 0.10) showed the highest acetylcholinesterase inhibitory activity. The Aβ25-35 induced cell damage was as evidenced at a concentration of 20μM. The neuroprotective effect of the ethanol extracts was examined in neurodegenerative cells induced by Aβ25-35. On pretreatment with plant extracts, significant improvement in cell viability was observed as 63.42 ± 2.02% (25μg/ml) for Commiphora berryi. The maximum percentage of in-vitro AChE inhibition and neuroprotective effect was effective in the ethanol bark extract of Commiphora berryi. Conclusion: The results are very rousing to continue the screening of more unexplored plant species could be used for the development of novel bioactive compounds to treat the many diseases, especially for Alzheimer's disease.

Application of Optimized and Validated Agar Overlay TLC-Bioautography Assay for Detecting the Antimicrobial Metabolites of Pharmaceutical Interest.

The agar overlay TLC-bioautography is one of the crucial methods for simultaneous in situ detection and separation of antimicrobial metabolites of pharmaceutical interest. The main focus of this research relies on the dereplication of an antimicrobial metabolite coriloxin derived from mycoendophytic Xylaria sp. NBRTSB-20 with a validation of agar overlay TLC-bioautography technique. This polyketide metabolite coriloxin was purified by column chromatography, and its purity was assessed by HPLC, UPLC-ESI-QTOF-MS, FT-IR and NMR spectral analysis. The antimicrobial capability of ethyl acetate extract and the purified compound coriloxin was determined by disc diffusion, minimal inhibitory concentration and agar overlay TLC-bioautography assay. The visible LOD of coriloxin antimicrobial activity was found at 10μg for Escherichia coli and 20μg for both Staphylococcus aureus and Fusarium oxysporum. Inter- and intra-day precision was determined as the relative standard deviation is less than 6.56%, which proved that this method was precise. The accuracy was expressed as recovery, and the values were found ranging from 91.18 to 108.73% with RSD values 0.94-2.30%, respectively. The overall findings of this investigation suggest that agar overlay TLC-bioautography assay is a suitable and acceptable method for the in situ determination of antimicrobial pharmaceuticals.

The new koninginins T-U from Phomopsis stipata, an endophytic fungus isolated from Styrax camporum Pohl

Two new polyketides, named koninginin T (1) and U (2), were isolated from Phomopsis stipata - an endophytic fungus isolated from Styrax camporum Pohl. The structures of polyketides 1 and 2 were defined through the analysis of spectroscopic data. Antifungal and acetylcholinesterase inhibitory activities of these compounds were evaluated using TLC bioautographic assays. Compounds 1 and 2 displayed moderate antifungal activity and compound 1 showed acetylcholinesterase inhibitory activity.

Control of postharvest fungal pathogens in pome fruits by lipopeptides from a Bacillus sp. isolate SL-6

Considering the economic losses in the fruit processing industry caused by phytopathogenic diseases, Bacillus sp. SL-6 was isolated from freshwater samples of the Cruz de Piedra Reservoir (San Luis, Argentina) and selected for its antifungal activity against Penicillium expansum, Botrytis cinerea and Alternaria alternata. These fungi are recognized as the main causal agents of postharvest diseases of pome fruits in Argentina. Pears are an important export product while apples are one of the fruits that lead internal commercialization throughout the country. Morphological, biochemical and phylogenetic analyses clustered strain SL-6 with Bacillus velezensis. To unveil the antimicrobial activity of this strain, gene fragments from the biosynthetic pathway of three lipopeptide families, surfactin, iturin and fengycin, were amplified by PCR and its expression assessed by RT-PCR. Cell-free supernatant from batch culture displayed inhibition only against A. alternata and B. cinerea. Partial purification of lipopeptides in the methanolic extract retained all antagonistic activities and fengycin was detected as responsible for the antifungal activity by TLC-bioautography assay. During short storage at room temperature, disease incidence and severity reduction in apples provided values of 59 and 67% against B. cinerea, respectively. The appearance of rot symptoms caused by A. alternata challenge was delayed in comparison with non-treated control, yielding total protection after 21 days of storage. Medium-term storage under cold conditions significantly reduced infection rates by B. cinerea in pears, with values higher than 80%. Four fengycin A and two fengycin B homologues were identified as active compounds by MALDI TOF and LC-ESI-MS/MS analyses. Successful curative protection by lipopeptides-enriched extract is a promising result for the further development of a biocontrol by-product as an alternative method for prevention of these pome fruit postharvest diseases.

Molecular profiling of endophytic Streptomyces cavourensis MH16 inhabiting Millingtonia hortensis Linn. and influence of different culture media on biosynthesis of antimicrobial metabolites.

Endophytic actinomycetes, a prolific source of natural products, are well known for their diverse metabolic versatility, and their association with medicinal plants and antimicrobial potential are well worth exploring. We isolated and identified the Streptomyces cavourensis strain MH16 inhabiting the tree Millingtonia hortensis Linn. using phylogenetic analysis based on a 16S rRNA molecular approach. We used the disc diffusion method to evaluate the impact of differences in the compositions of the media on the production of secondary metabolites from strain MH16. The production of antimicrobial metabolites was determined by the observation of inhibition zones on intensive bands when using a TLC-bioautography assay. Biosynthesis of secondary metabolites was optimal when the strain MH16 was cultured in ISP-2 medium as depicted by a zone of inhibition. Strain MH16 effectively inhibited methicillin-resistant Staphylococcus aureus, Escherichia coli, Candida albicans, and other multi drug-resistant pathogens. The minimum inhibitory concentration of the antimicrobial metabolites was 25-100μgmL-1. The study manifests the optimization and utilization of different fermentation media which best suits for increased production of the secondary metabolites from Streptomyces cavourensis. This research suggests that the antimicrobial metabolites of strain MH16 found in M. hortensis has great potential for the biodiscovery of new anti-infective drugs against a wide range of multidrug-resistant pathogens.

TLC-electrostatic field induced spray ionization-MS analysis of diverse structural skeletons and its coupling with TLC bioautography for characterization of lipase inhibitory components in American ginseng

Natural compounds with diverse structural skeletons have different ionization efficiencies and different mass spectrometry (MS) responses. Some key factors influencing the electrostatic field induced spray ionization (EFISI)-MS for a variety of natural compounds have been optimized and improved. Fifteen reference substances representing ten well-known skeletons of natural products including alkaloids, flavonoids, phenolic acids, lignans, coumarins, anthraquinones, monoterpenoids, sesquiterpenoids, diterpenoids and triterpenoids, were selected and investigated for their EFISI-MSn responses on TLC plates using a dot-blot test. The optimized ionization conditions for these compounds in the positive ion mode were achieved, together with their limits of detection. In addition, to avoid the limitation of some compounds being difficultly ionized in the positive ion mode, the negative ion mode of the TLC-EFISI-MS method was developed and optimized for the first time. By coupling with a TLC bioautographic assay, nine lipase inhibitory components in American ginseng (Panax quinquefolium roots) have been successfully identified/ tentatively identified in situ by their EFISI-MSn data and further confirmed by comparisons of their Rf values and MSn data with those of reference substances. These lipase inhibitory compounds were 24(S)-pseudo-ginsenoside F11, ginsenosides Rg1, Re, XVII, Rc, Rb2/Rb3, Rb1, Ro and malonyl-ginsenoside Rb1. This is the first report that the TLC-EFISI-MSn method is adapted to a broad-spectrum analysis of structural skeletons present in herbal medicines.

Antimicrobial, DPPH scavenging and tyrosinase inhibitory activities of Thymus vulgaris, Helichrysum arenarium and Rosa damascena mill. ethanol extracts by using TLC bioautography and chemical screening methods

Antimicrobial, DPPH scavenging and tyrosinase inhibitory activities of Thymus vulgaris, Helichrysum arenarium and Rosa damascena Mill. ethanol extracts by using TLC bioautography and chemical screening methods. The ethanol extracts of Thymus vulgaris (Tv), Helichrysum arenarium (Ha) and Rosa damascena Mill. (Rm) (red) were screened for their antimicrobial, 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and tyrosinase inhibitory activities. The test microorganisms included bacteria of Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 25923). Thin Layer Chromatography (TLC) - bioautography, disk diffusion and well diffusion methods were used for the antimicrobial activity assays. Rosa damascena Mill. extract was effective against E. coli and all plant extracts showed antimicrobial activity against S. aureus. The phenolic acids in the structure of the extracts were also identified by LC-MS analysis. Human blood agar well diffusion method and TLC-DPPH assays were used to identify the hemolytic and antioxidant activity of plant extracts, respectively, along with 10 compounds including phenolic acids as a standard. Among these compounds, caffeic acid (Rf = 0.68) was detected in all extracts while vanillic acid (Rf = 0.75), and gallic acid (Rf = 0.51) was found in Tv extract. Kojic acid (Rf = 0.36), on the other hand, was detected in Rm extract as a tyrosinase inhibitor. All plant extracts presented tyrosinase inhibitory activities on TLC-bioautography assay.

Comparison of Essential Oils of Ferulago pachyloba (Fenzl) Boiss., F. trachycarpa Boiss. and F. bracteata Boiss. & Hausskn. Species (Apiaceae) Growing in Turkey and Determination of Their Antimicrobial Activities

Ferulago species have been utilized since ancient times as antihelmentic, digestive, sedative and aphrodisiac, along with in salads or as a seasoning in view of their special odours. F. pachyloba (Fenzl) Boiss., F. trachycarpa Boiss. and F. bracteata Boiss. & Hausskn. species were investigated for their chemical compositions of essential oils and their antimicrobial activities. Antimicrobial activities of essential oils were performed via microbroth-dilution and TLC bioautography methods. GC and GC/MS were utilized to analyse the essential oils. Primary components of aerial parts, flowers, roots and fruits of F. pachyloba were found as, sabinene (16.0 %), (Z)-β-ocimene (15.1 %); sabinene (25.8 %), (Z)-β-ocimene (27.5 %); (E)-2-decenal (14.3 %); bicyclogermacrene (11.1 %), respectively. Primary components of aerial parts, roots and fruits of F. trachycarpa were found as, (Z)-β-ocimene (13.8 %), spathulenol (25.0 %); (E)-2-decenal (11.9 %); spathulenol (32.8 %), bicyclogermacrene (23.0 %). Primary components of aerial parts, flowers and roots of F. bracteata were found as, 7-methoxy-6-(3-methyl-2-butenyl)-coumarin (86.7 %); α-pinene (12.1 %), α-phellandrene (22.8 %); (E)-2- decenal (13.9 %), hexadecanoic acid (40.4 %). Essential oils were particularly more effective against Staphylococcus aureus, with MIC values of between 0.39 and 6.25 μg/mL, respectively. They did not give significant inhibition against Pseudomonas aeruginosa by TLC bioautography assay. In contrast, they had active components against S. aureus and showed significant inhibition. The antimicrobial activities against these microorganisms from these species may be attributed to the presence of the main components in the essential oils.

A Phytotoxic and Antifungal Metabolite (Pyrichalasin H) from a Fungus Infecting <i>Brachiaria eruciformis</i> (Signal Grass)

Brachiaria eruciformis (sm.) Griseb, locally known as “signal grass”, is a common weed in lawns and turfs in Mississippi, USA. During late spring and early summer months, leaves of B. eruciformis are infected with a fungus causing necrosis. The infected leaves ultimately turn brown and wither. As part of our search for potential new natural product-based agrochemicals, we studied this plant pathogen in order to investigate phytotoxic and fungitoxic metabolites produced by the fungus. The causative fungus was isolated from an infected leaf of B. eruciformis, cultured in potato dextrose agar plates and identified via molecular techniques as Pyricularia grisea. A phytotoxic compound was isolated from Czapek-Dox broth liquid culture medium and identified as pyrichalasin H by spectroscopic techniques. Pyrichalasin H was toxic to the fungal plant pathogen Colletotrichum fragariae in a TLC bioautography assay and phytotoxic to two monocot and one dicot plants. This is the first report of antifungal activity of pyrichalasin H against phytopathogens. Pyrichalasin H isolated from Pyricularia grisea, a pathogen infecting B. eruciformis (signal grass) was shown to be phytotoxic and fungicidal to Colletotrichum fragariae.

Plagiochianins A and B, Two ent-2,3-seco-Aromadendrane Derivatives from the Liverwort Plagiochila duthiana

Two novel ent-aromadendrane derivatives, plagiochianin A (1), possessing an unprecedented 2,3:6,7-di- seco-6,8-cyclo-aromadendrane carbon scaffold conjugated with three cyclic acetals, and plagiochianin B (2), an exceptional pyridine type aromadendrane alkaloid, were isolated from the Chinese liverwort Plagiochila duthiana. Their structures were established by comprehensive spectroscopic analysis coupled with single-crystal X-ray diffraction and electronic circular dichroism calculations. A plausible biogenetic pathway of these two compounds is presented, and their acetylcholinesterase inhibitory activities are preliminarily tested using TLC-bioautographic assays.

Anticholinesterase activities of methanol extract and partitioned fractions of <i>Acanthospermum hispidum</i> DC

Age related memory loss is a common occurrence in traditional medical practice and several medicinal plants have been used over the years for managing it. Acanthospermum hispidum DC (Asteraceae) is a medicinal plant that has been included in traditional preparations used in the management of memory loss. In clinical practice however, anticholinesterases have remained relevant in managing memory and cognition dysfunction associated both with old age and certain neurodegenerative diseases. In vitro anticholinesterase activity of extracts and fractions of A. hispidum was done using Ellman’s colorimetric and TLC bioautography assay with eserine as control. The ethyl acetate fraction of A. hispidum showed highest inhibition to acetylcholinesterase and butyrylcholinesterase (91.11% and 64.31%, respectively) in a concentration-dependent manner. A. hispidum presents a good prospect in the development of cholinesterase inhibitors for the management of memory-related disorders. Keywords: Acanthospermum hispidum , Anticholinesterase, acetylcholinesterase, butyrylcholinesterase