Displaying publications 1 - 20 of 93 in total

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  1. Fulltext Biodiversity of Secondary Metabolites Compounds Isolated from Phylum Actinobacteria and Its Therapeutic Applications
    Al-Shaibani MM, Radin Mohamed RMS, Sidik NM, Enshasy HAE, Al-Gheethi A, Noman E, et al.
    Molecules, 2021 Jul 26;26(15).
    PMID: 34361657 DOI: 10.3390/molecules26154504
    The current review aims to summarise the biodiversity and biosynthesis of novel secondary metabolites compounds, of the phylum Actinobacteria and the diverse range of secondary metabolites produced that vary depending on its ecological environments they inhabit. Actinobacteria creates a wide range of bioactive substances that can be of great value to public health and the pharmaceutical industry. The literature analysis process for this review was conducted using the VOSviewer software tool to visualise the bibliometric networks of the most relevant databases from the Scopus database in the period between 2010 and 22 March 2021. Screening and exploring the available literature relating to the extreme environments and ecosystems that Actinobacteria inhabit aims to identify new strains of this major microorganism class, producing unique novel bioactive compounds. The knowledge gained from these studies is intended to encourage scientists in the natural product discovery field to identify and characterise novel strains containing various bioactive gene clusters with potential clinical applications. It is evident that Actinobacteria adapted to survive in extreme environments represent an important source of a wide range of bioactive compounds. Actinobacteria have a large number of secondary metabolite biosynthetic gene clusters. They can synthesise thousands of subordinate metabolites with different biological actions such as anti-bacterial, anti-parasitic, anti-fungal, anti-virus, anti-cancer and growth-promoting compounds. These are highly significant economically due to their potential applications in the food, nutrition and health industries and thus support our communities' well-being.
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification
  2. Fulltext Antibacterial activities of a new brominated diterpene from Borneon Laurencia spp
    Vairappan CS, Ishii T, Lee TK, Suzuki M, Zhaoqi Z
    Mar Drugs, 2010;8(6):1743-9.
    PMID: 20631866 DOI: 10.3390/md8061743
    In our continuous interest to study the diversity of halogenated metabolites of Malaysian species of the red algal genus Laurencia, we examined the chemical composition of five populations of unrecorded Laurencia sp. A new brominated diterpene, 10-acetoxyangasiol (1), and four other known metabolites, aplysidiol (2), cupalaurenol (3), 1-methyl-2,3,5-tribromoindole (4), and chamigrane epoxide (5), were isolated and identified. Isolated metabolites exhibited potent antibacterial activities against clinical bacteria, Staphylococcus aureus, Staphylococcus sp., Streptococcus pyogenes, Salmonella sp. and Vibrio cholerae.
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification
  3. Resistoflavine, cytotoxic compound from a marine actinomycete, Streptomyces chibaensis AUBN1/7
    Gorajana A, Venkatesan M, Vinjamuri S, Kurada BV, Peela S, Jangam P, et al.
    Microbiol Res, 2007;162(4):322-7.
    PMID: 16580188
    In our systematic screening programme for marine actinomycetes, a bioactive Streptomycete was isolated from marine sediment samples of Bay of Bengal, India. The taxonomic studies indicated that the isolate belongs to Streptomyces chibaensis and it was designated as S. chibaensis AUBN1/7. The isolate yielded a cytotoxic compound. It was obtained by solvent extraction followed by the chromatographic purification. Based on the spectral data of the pure compound, it was identified as quinone-related antibiotic, resistoflavine (1). It showed a potent cytotoxic activity against cell lines viz. HMO2 (Gastric adenocarcinoma) and HePG2 (Hepatic carcinoma) in vitro and also exhibited weak antibacterial activities against Gram-positive and Gram-negative bacteria.
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification*
  4. Fulltext Phytochemical analysis of Andrographis paniculata and Orthosiphon stamineus leaf extracts for their antibacterial and antioxidant potential
    Malahubban M, Alimon AR, Sazili AQ, Fakurazi S, Zakry FA
    Trop Biomed, 2013 Sep;30(3):467-80.
    PMID: 24189677 MyJurnal
    Leaves of Andrographis paniculata and Orthosiphon stamineus were extracted with water, ethanol, methanol and chloroform to assess their potential as antibacterial and antioxidant agents. High performance liquid chromatography analysis showed that the methanolic extracts of A. paniculata and O. stamineus leaves gave the highest amounts of andrographolide and rosmarinic acid, respectively. These leaf extracts exhibited antimicrobial and antioxidant activities and, at the highest concentration tested (200 mg/mL), showed greater inhibitory effects against the Gram positive bacteria Bacillus cereus and Staphylococcus aureus than 10% acetic acid. Andrographis paniculata and O. stamineus methanolic and ethanolic leaf extracts also showed the strongest antioxidant activity as compared with the other extracts tested. The bioactive compounds present in these leaf extracts have the potential to be developed into natural antibacterial and antioxidant agents that may have applications in animal and human health.
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification
  5. Inhibition of Klebsiella pneumoniae ATCC 13883 cells by hexane extract of Halimeda discoidea (Decaisne) and the identification of its potential bioactive compounds
    Supardy NA, Ibrahim D, Sulaiman SF, Zakaria NA
    J Microbiol Biotechnol, 2012 Jun;22(6):872-81.
    PMID: 22573167
    The inhibitory effect of the Klebsiella pneumoniae ATCC 13883 strain caused by the hexane extract of Halimeda discoidea (Nor Afifah et al., 2010) was further evaluated by means of the microscopy view and its growth curves. The morphological changes of the K. pneumoniae ATCC 13883 cells were observed under the scanning electron microscope (SEM) and transmission electron microscope (TEM) after they were treated at minimum inhibitory concentration (MIC; 0.50 mg/ml) (Nor Afifah et al., 2010) for 12, 24, and 36 h. The results showed the severity of the morphological deteriorations experienced by the treated cells. The killing curve assay was performed for 48 h at three different extract concentrations (1/2 MIC, MIC, and 2 MIC). An increase in the extract concentration of up to 2 MIC value did significantly reduce the number of cells by approximately 1.9 log10, as compared with the control. Identification of the potential compounds of the extract responsible for the antibacterial activity was carried out through the gas chromatography-mass spectrum (GCMS) analysis of the active subfraction, and the compound E-15-heptadecenal was identified and suggested as the most potential antibacterial compound of this extract. The subsequent cellular degenerations showed by the data might well explain the inhibitory mechanisms of the suggested antibacterial compound. All of these inhibitory effects have further proven the presence of an antibacterial compound within H. discoidea that can inhibit the growth of K. pneumoniae ATCC 13883.
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification
  6. Chemical compositions and biological activities of the essential oils of Beilschmiedia madang Blume (Lauraceae)
    Salleh WM, Ahmad F, Yen KH
    Arch Pharm Res, 2015 Apr;38(4):485-93.
    PMID: 25098422 DOI: 10.1007/s12272-014-0460-z
    The present study aimed to examine the chemical compositions of the essential oils of Beilschmiedia madang and their antioxidant, antibacterial, antifungal, anticholinesterase and anti-tyrosinase activities. The major constituents of the essential oils of leaf and bark of B. madang were δ-cadinene (17.0 and 20.5 %), β-caryophyllene (10.3 and 6.7 %), α-cubebene (11.3 and 15.6 %), and α-cadinol (5.8 and 10.6 %). The essential oils were screened for their antioxidant activities using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, β-carotene/linoleic acid bleaching, and total phenolic content. The bark oil showed the highest β-carotene/linoleic acid bleaching (90.3 % ± 0.2) and DPPH radical scavenging (IC50 212.0 µg/mL), while the highest phenolic content was exhibited by the leaf oil (94.5 % ± 0.3 mg GA/g). The antibacterial and antifungal activities were investigated by the disc diffusion and micro dilution method. The leaf and bark oils showed moderate activity towards Bacillus subtilis and Staphylococcus aureus with minimum inhibitory concentration (MIC) value 125 µg/mL. For antifungal assay, the bark oil showed strong activity towards Aspergillus niger and Aspergillus fumigatus with MIC value 62.5 µg/mL. Anticholinesterase and anti-tyrosinase activities were evaluated against Ellman method and mushroom tyrosinase, respectively. The results showed that leaf oil gave significant percentage inhibition (I%: acetylcholinesterase 55.2 %, butyrylcholinesterase 60.4 %, tyrosinase 53.1 %).
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification
  7. Molecularly imprinted silica gel incorporated with agarose polymer matrix as mixed matrix membrane for separation and preconcentration of sulfonamide antibiotics in water samples
    Rozaini MNH, Semail NF, Saad B, Kamaruzaman S, Abdullah WN, Rahim NA, et al.
    Talanta, 2019 Jul 01;199:522-531.
    PMID: 30952293 DOI: 10.1016/j.talanta.2019.02.096
    Molecularly imprinted silica gel (MISG) was incorporated through dispersion in agarose polymer matrix to form a mixed matrix membrane (MMM) and was applied for the determination of three sulfonamide antibiotic compounds (i.e. sulfamethoxazole (SMX), sulfamonomethoxine (SMM), and sulfadiazine (SDZ)) from environmental water samples. Several important microextraction conditions, such as type of desorption solvent, extraction time, amount of sorbent, sample volume, pH, and effect of desorption time, were comprehensively optimized. A preconcentration factors of ≥ 20 was achieved by the extraction of 12.5 mL of water samples using the developed method. This microextraction-HPLC method demonstrated good linearity (1-500 μg L-1) with a coefficient of determination (R2) of 0.9959-0.9999, low limits of detection (0.06-0.17 μg L-1) and limits of quantification (0.20-0.56 μg L-1), good analyte recoveries (80-96%), and acceptable relative standard deviations (< 10%) under the optimized conditions. The method is systematically compared to those reported in the literature.
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification*
  8. New compounds with antimicrobial activities from Elaeodendron buchananii stem bark
    Odak JA, Manguro LOA, Wong KC
    J Asian Nat Prod Res, 2018 Jun;20(6):510-524.
    PMID: 29338355 DOI: 10.1080/10286020.2017.1420648
    The plant species Elaeodendron buchananii Loes is widely used in folklore medicine to manage microbial infections in Kenya. Previous studies on the plant fruits and root bark revealed the presence of steroids and terpenoids. The present phytochemical analysis of the plant stem bark has led to the isolation of four new triterpenes characterized as methyl 3β-acetoxy-11α, 19α, 28-trihydroxyurs-12-en-23-oic acid (1), 3β, 11α, 19α-trihydroxyurs-12-en-23, 28-dioic acid (2), 3β-acetoxy-19α, 23, 28-trihydroxyurs-12-ene (3) and 3-oxo-19α, 28-dihydroxyurs-12-en-24-oic acid (4), together with ten known ones (5-14), whose structures were elucidated using spectroscopic techniques. The isolate canophyllol (8) showed promising antibacterial activity against N. meningitides with MIC value of 31.25 μg/ml.
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification*
  9. Antibacterial alkaloids from Artabotrys crassifolius Hook.f. & Thomson
    Tan KK, Khoo TJ, Rajagopal M, Wiart C
    Nat Prod Res, 2015;29(24):2346-9.
    PMID: 25738993 DOI: 10.1080/14786419.2015.1013954
    Chloroform extract of bark of Artabotrys crassifolius Hook.f. & Thomson exhibited antibacterial activities against both American Type Culture Collection and clinical bacterial strains in vitro with zones of inhibition ranging from 7 to 14 mm. Further analysis of this extract yielded artabotrine, liridine, lysicamine and atherospermidine. Artabotrine displayed a broad array of antibacterial activity mostly against Gram-positive bacteria with minimum inhibitory concentration (MIC) values ranging from 1.25 μg/mL to 5 μg/mL. Of note, artabotrine, liridine and lysicamine are bactericidal against Gram-negative extended-spectrum beta-lactamase-producing Klebsiella with MIC values equal 2.5, 2.5 and 10 μg/mL, respectively, and minimum bactericidal concentrations values equal to 2.5, 5 and 20 μg/mL.
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification
  10. Fulltext Antibacterial effects of 18 medicinal plants used by the Khyang tribe in Bangladesh
    Hossan MS, Jindal H, Maisha S, Samudi Raju C, Devi Sekaran S, Nissapatorn V, et al.
    Pharm Biol, 2018 Dec;56(1):201-208.
    PMID: 29529970 DOI: 10.1080/13880209.2018.1446030
    CONTEXT: The resistance of bacteria to antibiotics is raising serious concern globally. Asian medicinal plants could improve the current treatment strategies for bacterial infections. The antibacterial properties of medicinal plants used by the Khyang tribe in Bangladesh have not been investigated.

    OBJECTIVE: The present study examines the antibacterial properties of 18 medicinal plants used by the Khyang tribe in day-to-day practice against human pathogenic bacteria.

    MATERIALS AND METHODS: Leaves, bark, fruits, seeds, roots and rhizomes from collected plants were successively extracted with hexane, ethyl acetate and ethanol. The corresponding 54 extracts were tested against six human pathogenic bacteria by broth microdilution assay. The antibacterial mode of actions of phytoconstituents and their synergistic effect with vancomycin and cefotaxime towards MRSA was determined by time-killing assay and synergistic interaction assay, respectively.

    RESULTS AND DISCUSSION: Hexane extract of bark of Cinnamomum cassia (L.) J. Presl. (Lauraceae) inhibited the growth of MRSA, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii with MIC values below 100 µg/mL. From this plant, cinnamaldehyde evoked at 4 × MIC in 1 h an irreversible decrease of MRSA count Log10 (CFU/mL) from 6 to 0, and was synergistic with vancomycin for MRSA with fractional inhibitory concentration index of 0.3.

    CONCLUSIONS: Our study provides evidence that the medicinal plants in Bangladesh have high potential to improve the current treatment strategies for bacterial infection.

    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification
  11. Purification and characterisation of antibacterial peptide-containing compound derived from palm kernel cake
    Tan YN, Ayob MK, Wan Yaacob WA
    Food Chem, 2013 Jan 1;136(1):279-84.
    PMID: 23017424 DOI: 10.1016/j.foodchem.2012.08.012
    Palm kernel cake (PKC), the most useful by-product resulted from palm kernel oil production. In this study, PKC-derived protein product was found suitable for use as an antimicrobial agent with potent antibacterial activity, particularly against Bacillus species, after enzymatic hydrolysis with alcalase. The hydrolysate was further purified by gel filtration chromatography. The purified fraction was found to have 14.63±0.70% (w/w) protein, a molecular mass of 2.4kDa and low hemolytic activity (<50% hemolysis of human erythrocytes at concentration of 1000μg/ml). The presence of lysine and the major component lauric acid derivative, as indicated by electrospray ionisation-mass spectrometry (ESI-MS) direct infusion and nuclear magnetic resonance (NMR) spectroscopy, may have contributed to the antibacterial effect of purified PKC fraction. This study suggests that the antibacterial PKC compound may be not a pure peptide but instead a peptide-containing compound high in lauric acid derivative.
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification*
  12. A new sesquiterpenoid from the rhizomes of Homalomena sagittifolia
    Wong KC, Hamid A, Eldeen IM, Asmawi MZ, Baharuddin S, Abdillahi HS, et al.
    Nat Prod Res, 2012;26(9):850-8.
    PMID: 21999629 DOI: 10.1080/14786419.2010.551770
    A new sesquiterpenoid, 1α,4β,7β-eudesmanetriol (1), was isolated together with the known compounds 1β,4β,7β-eudesmanetriol (2) and oplopanone (3) from the rhizomes of Homalomena sagittifolia. The structures of these compounds were determined by extensive spectral analyses. The compounds 1 and 2 inhibited growth of Pseudomonas stutzeri with a MIC value of 117 µM when evaluated for antibacterial activity using the minimum concentration assay. Both these compounds showed remarkable activities against acetylcholinesterase enzyme with IC(50) values ranging between 25 and 26 µM. The isolation of these sesquiterpenoids and their biological activities observed in this study support the reported traditional uses of H. sagittifolia for the treatment of microbial related diseases and central nervous system disorders.
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification
  13. Three new cembranoids from the Bornean soft coral Nephthea sp
    Ishii T, Kamada T, Vairappan CS
    J Asian Nat Prod Res, 2016 May;18(5):415-22.
    PMID: 26983053 DOI: 10.1080/10286020.2016.1145670
    Three new cembranoid diterpenes, 10-hydroxy-nephthenol acetate (1), 7,8-epoxy-10-hydroxy-nephthenol acetate (2), and 6-acetoxy-7,8-epoxy-10-hydroxy-nephthenol acetate (3), along with a known compound, 6-acetoxy-7,8-epoxy-nephthenol acetate (4), were isolated from the Bornean soft coral Nephthea sp. Antibacterial and anticancer activities were exhibited by compounds 1 and 2 against Staphylococcus aureus (ATCC 6538)/Escherichia coli (ATCC 13311) and Hela/MCF-7, respectively.
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification*
  14. Two new epimers of C15-acetogenin, 4-epi-isolaurallene and 4-epi-itomanallene A as diastereomeric model
    Phan CS, Kamada T, Vairappan CS
    Nat Prod Res, 2020 Apr;34(7):1008-1013.
    PMID: 30600714 DOI: 10.1080/14786419.2018.1543681
    Two new C15-acetogenins, 4-epi-isolaurallene (1) and 4-epi-itomanallene A (2) were isolated from a population of marine red alga Laurencia nangii Masuda from Carrington Reef. The structures of these compounds were determined intensively by NMR and HRESIMS data. Their configurations were elucidated by detailed comparison of chemical shifts, germinal protons splitting and NOE correlations with known and synthesized analogues. In addition, antibacterial activities of these compounds were evaluated. These compounds would serve as diastereomeric models for future reference. Since the isolaurallene, neolaurallene, 9-acetoxy-1,10,12-tribromo-4,7:6,13-bisepoxypentadeca-1,2-diene, itomanallene A and laurendecumallene A were isolated, compounds 1 and 2 were the sixth example of C15-acetogenin with dioxabicyclo[7.3.0]dodecene skeleton.
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification
  15. Non-halogenated new sesquiterpenes from Bornean Laurencia snackeyi
    Kamada T, Vairappan CS
    Nat Prod Res, 2017 Feb;31(3):333-340.
    PMID: 27707003
    Two new non-halogenated sesquiterpenes, snakeol (1) and snakediol (2) were isolated together with 9 known sesquiterpenes such as (R,Z)-33-dimethyl-5-methylene-4-(3-methylpenta-24-dien-1-yl)cyclohex-1-ene (3), palisol (4), pacifigorgiol (5), palisadin D (6), palisadin A (7), palisadin B (8), 5-acetoxypalisadin B (9), debromolaurinterol (10) and α-bromocuparane (11) from the red algae Laurencia snackeyi. The structures of two new metabolites were determined from their spectroscopic data (IR, 1D and 2D NMR and MS). Compounds 1, 2, 10 and 11 showed strong antibacterial activity against selected human clinical bacterial pathogens.
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification
  16. Capgermacrenes D-G, new sesquiterpenoids from a Bornean soft coral, Capnella imbricata
    Phan CS, Vairappan CS
    Nat Prod Res, 2017 Apr;31(7):742-748.
    PMID: 27750446 DOI: 10.1080/14786419.2016.1241997
    Four new bicyclogermacrenes, capgermacrenes D (1) E (2) F (3) and G (4) were isolated from a population of Bornean soft coral Capnella imbricata. The structures of these metabolites were elucidated based on their nuclear magnetic resonance and high-resolution electrospray ionisation mass spectrometry spectral data. These compounds showed bacteriastatic and bacteriacidal activities against Staphylococcus aureus and methicillin-resistant Staphylococcus aureus.
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification
  17. Bacterial dynamics associated with algal antibacterial substances during post harvest desiccation process of Sargassum stolonifolium Phang et Yoshida
    Vairappan CS
    Indian J Exp Biol, 2003 Aug;41(8):837-45.
    PMID: 15248481
    Brown algae of genus Sargassum are known to produce relatively higher amount of alginic acid. Optimal extraction of this algalcolloid for local consumption requires in-depth studies on post-harvest treatment of the algal fronds. Present investigation endeavors to establish the dynamics and inter-relationship of moisture content and bacteria found on the surface of the alga and alginic acid content during post-harvest desiccation of Sargassum stolonifolium Phang et Yoshida. Harvested fronds were subjected to desiccation for 31 days and bacterial dynamics were monitored with relation to moisture content and water activity index (a(w)). There was 85% decrease in moisture content, however, a(w) showed a more gradual decrease. Total bacterial count increased during the first week and attained maximal value on day 7. Thereafter, a drastic decrease was seen until day 14, followed by a gradual decline. Six species of bacteria were isolated and identified, i.e. Azomonas punctata, Azomonas sp., Escherichia coli, Micrococcus sp., Proteus vulgaris and Vibrio alginolyticus. Calculated ratios for increase in alginic acid content and decrease in moisture content were almost the same throughout the desiccation process, implying that extracellular alginase-producing bacteria did not use the alginic acid produced by the algae as its carbon source. It became apparent that drastic decrease in bacterial count after day 7 could not be attributed to salinity, moisture content, a(w) or lack of carbon source for the bacteria. The possible exposure of these bacteria to algal cell sap which is formed due to the rupture of algal cells was seen as the most likely reason for the drop in bacterial population. Scanning electron microscope (SEM) micrograph taken on day 10 of desiccation showed the presence of cracks and localities where bacteria were exposed to algal cell sap. In vitro antibacterial tests were carried out to verify the effect of algal extracts. Separation and purification of crude algal extracts via bioassay guided separation methodology revealed the identity of active compounds (i.e. gylcolipids and free fatty acids) involved in this inherently available antibacterial defense mechanism during algal desiccation.
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification
  18. Search for antibacterial agents from Malaysian rainforest and tropical plants
    Othman M, Genapathy S, Liew PS, Ch'ng QT, Loh HS, Khoo TJ, et al.
    Nat Prod Res, 2011 Nov;25(19):1857-64.
    PMID: 21838540 DOI: 10.1080/14786419.2010.537274
    The world's rainforests hold untold potential for drug discovery. Rainforest plants are thought to contain evolved defensive active metabolites of greater diversity compared to plants from temperate regions. In recent years, the interest and overall output from pharmaceutical companies on novel antibacterial agents has diminished at a time when there is a critical need for them to fight the threat of resistance. In this study, we have investigated the antimicrobial properties of 21 flowering plants from 16 different families against six bacterial strains consisting of two Gram negative and four Gram positive. Using the pour plate disc diffusion technique, almost all extracts from these plants were found to be active against some of the bacterial strains tested. The most interesting and active plants with broad spectrum activities include Duabanga grandiflora, Acalypha wilkesiana and Pseuduvaria macrophylla where the minimum inhibitory concentration, minimum bactericidal concentration and phytochemical analysis were carried out. This is the first report describing the antimicrobial and phytochemical properties of D. grandiflora and P. macrophylla. Our findings support the utilisation of higher plant species in the search for new antimicrobial molecules to combat new emerging infective diseases and the problem of drug resistant pathogens.
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification
  19. An antibacterial metabolite from Lasiodiplodia pseudotheobromae F2
    Wei W, Jiang N, Mei YN, Chu YL, Ge HM, Song YC, et al.
    Phytochemistry, 2014 Apr;100:103-9.
    PMID: 24529576 DOI: 10.1016/j.phytochem.2014.01.003
    In searching for symbionts derived from bioactive natural products, six sulfureous diketopiperazines designated as lasiodiplines A-F (1-6) were characterized from the culture of Lasiodiplodia pseudotheobromae F2, previously residing in the apparently normal flower of Illigera rhodantha (Hernandiaceae). Identification of structures was accomplished by a combination of spectroscopic and computational approaches, in conjunction with the low-temperature (100K) single-crystal X-ray diffraction with Cu Kα radiation. Lasiodipline E (5) was demonstrated to be antibacterial against the clinical strains Streptococcus sp., Bacteroides vulgates, Peptostreptococcus sp. and Veillonella parvula, respectively, with an minimum inhibitory concentration (MIC) range of 0.12-0.25 μg/mL. In addition, compounds 4 and 6 exemplify two unusual architectures of natural cyclodipeptides, signifying the unique biochemical characteristics of the producing fungus.
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification
  20. Tyrosinase inhibition, anti-acetylcholinesterase, and antimicrobial activities of the phytochemicals from Gynotroches axillaris Blume
    Abed SA, Sirat HM, Taher M
    Pak J Pharm Sci, 2016 Nov;29(6):2071-2078.
    PMID: 28375126
    The leaves of Gynotroches axillaris were chemically and biologically studied. Sequential extraction of the leaves using petroleum ether, chloroform, and methanol afforded three extracts. Purification of pet. ether extract yielded, squalene and β-amyrin palmitate as the major compounds, together with palmitic acid and myristic acid as the minor components. The methanol extract yielded two flavonoids, quercitrin and epicatechin. The isolated compounds were characterized by MS, IR and NMR (1D and 2D). Anti-acetyl cholinesterase screening using TLC bio-autography assay showed that palmitic acid and myristic acid were the strongest inhibition with detection limit 1.14 and 1.28 μ/g/ 5 μL respectively. Antibacterial against Gram-positive and negative and antifungal activities exhibited that β-amyrin palmitate was the strongest (450-225 μ/mL) against all the tested microbes. The tyrosinase inhibition assay of extracts and the pure compounds were screened against tyrosinase enzyme. The inhibition percentage (I%) of methanol extract against tyrosinase enzyme was stronger than the other extracts with value 68.4%. Quercitrin (59%) was found to be the highest in the tyrosinase inhibition activity amongst the pure compounds. To the best of our knowledge, this is first report on the phytochemicals, tyrosinase inhibition, anti-acetycholinesterase and antimicrobial activities of the leaves of G. axillaris.
    Matched MeSH terms: Anti-Bacterial Agents/isolation & purification
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