Dabsylated Bradykinin Is Cleaved by Snake Venom Proteases from Echis ocellatus.

The vasoactive peptide bradykinin (BK) is an important member of the renin-angiotensin system. Its discovery is tightly interwoven with snake venom research, because it was first detected in plasma following the addition of viper venom. While the fact that venoms liberate BK from a serum globulin fraction is well described, its destruction by the venom has largely gone unnoticed. Here, BK was found to be cleaved by snake venom metalloproteinases in the venom of Echis ocellatus, one of the deadliest snakes, which degraded its dabsylated form (DBK) in a few minutes after Pro7 (RPPGFSP↓FR). This is a common cleavage site for several mammalian proteases such as ACE, but is not typical for matrix metalloproteinases. Residual protease activity < 5% after addition of EDTA indicated that DBK is also cleaved by serine proteases to a minor extent. Mass spectrometry-based protein analysis provided spectral proof for several peptides of zinc metalloproteinase-disintegrin-like Eoc1, disintegrin EO4A, and three serine proteases in the venom.

Chemical Constituents from Ficus sagittifolia Stem Bark and Their Antimicrobial Activities.

The phytochemical investigation of the ethylacetate fraction of an ethanolic extract obtained from the stem bark of Ficus sagittifolia (Moraceae) led to the isolation of four flavonoids: (2R)-eriodictyol (1), 2'- hydroxygenistein (2), erycibenin A (3), and genistein (4); a dihydrobenzofuran: moracin P (5); a coumarin: peucedanol (6); and an apocarotenoid terpenoid: dihydrophaseic acid (7). These were identified via 1D and 2D nuclear magnetic resonance spectroscopy (NMR) and ultra-high-resolution liquid chromatography-quadrupole time-of-flight mass spectroscopy (UHPLC-QTOF MS). Moracin P (5) is being reported for the first time in the genus Ficus, while the others are known compounds (1-4 and 6-7) isolated previously from the genus but being reported for the first time from the species F. sagittifolia. Their antimicrobial activity against various pathogens (five bacteria: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Salmonella typhi; two fungi: Aspergillus niger and Candida albicans) was tested. The mixture of genistein and moracin P (4+5) exhibited strong activity against K. pneumoniae (MIC < 0.0039 mg/mL), whereas dihydrophaseic acid (7) was the most active against P. aeruginosa and A. niger (MIC = 0.0078 and <0.0039 mg/mL, respectively). These compounds might be considered potential antimicrobial agents with the potential to be starting points for the development of antimicrobial drugs.

Gakolanone: a new benzophenone derivative from Garcinia kola Heckel stem-bark.

Gakolanone (3',5'-digeranyl-2',4',6',3-tetrahydroxybenzophenone; 1), a novel benzophenone derivative was isolated from the hexane extract of Garcinia kola Heckel stem-bark along with three known 3-8'' linked biflavonoids: 3'',4',4''',5,5'',7,7''-heptahydroxy-3,8''-biflavanone (2); 3'',4',5,5'',5''',7,7''-heptahydroxy-4-methoxy-3,8''-biflavanone (3) and 4',4''',5,5'',7,7''-hexahydroxy-3,8''-biflavanone (4) from the ethanol extract. The compounds were characterized primarily using 1 D and 2 D nuclear magnetic resonance spectroscopy and mass spectrometry and by comparing with literature. The compounds were subjected to in-vitro alpha-amylase enzyme inhibitory assay using DNSA (3,5-dinitrosalicylic acid) reagent with acarbose used as the standard drug. All the compounds were found to show alpha-amylase inhibitory activities with IC50 of 21.4 ± 1.5, 9.9 ± 0.2, 15.3 ± 2.3, 12.9 ± 2.3 µg/mL respectively. All the compounds exhibited better alpha-amylase inhibitory activities than the standard drug, acarbose (IC50= 38.1 ± 8.3 µg/mL).

Isolation and antiproliferative activity of triterpenoids and fatty acids from the leaves and stem of Turraea vogelii Hook. f. ex benth.

Chloroform extract from the leaves of Turraea vogelii Hook f. ex Benth demonstrated cytotoxic activity against a chronic myelogenous leukemia cell, K-562 with IC50 of 14.27 µg/mL, while chloroform, ethyl acetate and methanol extracts from the stem of the plant inhibited K-562 cells growth with IC50 of 19.50, 24.10 and 85.40 µg/mL respectively. Bioactive chloroform extract of Turraea vogelii leaves affords two triterpenoids: oleana-12,15,20-trien-3ß-ol (1), and oleana-11,13-dien-3ß,16α,28-triol (2), with six fatty esters, ethyl hexaeicos-5-enoate (3), 3-hydroxy-1,2,3-propanetriyltris(tetadecanoate) (4), 1,2,3-propanetriyl(7Z,7'Z,7''Z)tris(-7-hexadecenoate) (5), 1,2,3-propanetriyl(5Z,5'Z,5''Z)tris(-5-hexadecenoate) (6), 1,2,3-propanetriyltris(octadecanoate) (7), and 2ß-hydroxymethyl tetraeicosanoate (8). Tetradecane (9), four fatty acids: hexadecanoic acid (10), tetradecanoic acid (11), (Z)-9-eicosenoic acid (12), and ethyl tetradec-7-enoate (13) were isolated from chloroform extract of Turraea vogelii stem. 1,2,3-propanetriyltris(heptadecanoate) (14), (Z)-9-octadecenoic acid (15) and (Z)-7-tetradecenoic acid (16) were isolated from ethyl acetate extract while (Z)-5-pentadecenoic acid (17) was obtained from methanol extract of the plant stem. Compounds 1, 2, 5, 6, 11, 12, 15, 16 and 17 exhibited pronounced antiproliferative activity against K-562 cell lines.

Isolation and antiproliferative activity of chemical constituents from Asystasia buettneri Lindau.

N-hexane and methanol extracts of Asystasia buettneri Lindau aerial parts exhibited antiproliferative activity on leukaemia blood carcinoma, K-562. Hexadecane (1), 1,3-propan-2-ol (9Z,12'Z,15″Z)-bis(doeicos-9,12,15-trienoate) (2), hydrocarbon, 2,3,3,10,23-pentamethyl tetraeicos-10,13,16-trien-1-ol (3), hexadecanoic acid (4) and taraxerol (5) were isolated from n-hexane extract; stigmasterol (6) and (Z)-9-octadecenoic acid (7) were isolated from ethyl acetate extract; while unsaturated hydrocarbons, octadecene (8), 8-methyl tetradec-6-ene (9) and 19-methyl eicos-1-ene (10), fatty acids, (Z)-5-hexadecenoic acid (11), 11,22-dimethyl ethyltrieicos-11-enoate (12) and taraxasterol (13) were isolated from methanol extract of the plant. Compounds 4, 5, 7, 11, 12 and 13 exhibited antiproliferative activity against K-562, while compounds 5, 6, 7 and 9 revealed antiproliferative activity by inhibiting hepatic liver (WRL68) cell lines.

Evaluation of therapeutic potentials of plant extracts against poultry bacteria threatening public health.

BACKGROUND: Plant extracts were evaluated on poultry bacteria known to be threatening public health. This is to develop better bio-therapeutic agents from plant origin. METHODS: Bacteria were isolated from water, feed, crop, gizzard and faeces of layer chicken. Isolates of interest (Escherichia coli, Salmonella enteritidis, Pseudomonas aeruginosa and Klebsiella oxytoca) were subjected to antibiotic susceptibility test. Resistant strains were further evaluated against different plant extracts in comparison to Meropenem (control) using agar diffusion method. RESULTS: E. coli had the highest occurrence (53 %), followed by P. aeruginosa (25 %) and then S. enteritidis (13 %) while the least was K. oxytoca (9 %). Virtually all the isolates exhibited multi-antibiotic resistance (MAR) with gross resistance to Amoxicillin, Erythromycin and Cefuroxine. P. aeruginosa (75 %), S. enteritidis (75 %) and E. coli (63 %), had the highest MAR. Out of the 11 (100 %) plant extracts evaluated, 7 (64 %) were outstanding and showed varied levels of antibacterial activity. Specifically, methanol extract of Mangifera indica Julie cultivar leaf (MJLM) had the highest antibacterial activity, followed by Euadenia trifoliata stem bark (TB03) and Euadenia eminens leaf (TB05). P. aeruginosa was highly susceptible (81.81 %) to the extracts, followed by S. enteritidis (63.64 %) and then E. coli (27.27 %). CONCLUSIONS: MJLM and other extracts have proven to be promising extracts in which to search for bioactive components that can be developed into therapeutic drugs. This may help in the management of antibiotic resistant bacterial isolates from poultry chicken threatening public health.

Some Nigerian anti-tuberculosis ethnomedicines: a preliminary efficacy assessment.

ETHNOPHARMACOLOGICAL SIGNIFICANCE: Nigerian herbalists possess indigenous ethnomedicinal recipes for the management of tuberculosis and related ailments. A collaborative preliminary modern scientific evaluation of the efficacy of some Nigerian ethnomedicines used by traditional medicine practitioners (TMPs) in the management of tuberculosis and related ailments has been carried out. MATERIALS AND METHODS: Ethnomedicinal recipes (ETMs) were collected from TMPs from locations in various ecological zones of Nigeria under a collaborative understanding. The aqueous methanolic extracts of the ETMs were screened against Mycobacterium bovis, BCG and Mycobacterium tuberculosis strain H37Rv using the broth microdilution method. RESULTS: Extracts of ETMs screened against BCG showed 69% activity against the organism. The activities varied from weak, ≤2500 µg/mL to highly active, 33 µg/mL 64% of the extracts were active against Mycobacterium tuberculosis The activities of the extracts against Mycobacterium tuberculosis varied from weak, ≤2500 µg/mL to highly active, 128 µg/mL. There was 77% agreement in results obtained using BCG or Mycobacterium tuberculosis as test organisms. CONCLUSION: The results show clear evidence for the efficacy of the majority of indigenous Nigerian herbal recipes in the ethnomedicinal management of tuberculosis and related ailments. BCG may be effectively used, to a great extent, as the organism for screening for potential anti-Mycobacterium tuberculosis agents. A set of prioritization criteria for the selection of plants for initial further studies for the purpose of antituberculosis drug discovery research is proposed.

Cytotoxic Activity of Crude Extracts as well as of Pure Components from Jatropha Species, Plants Used Extensively in African Traditional Medicine.

Extracts from Jatropha curcas, a plant used in African traditional medicine for various diseases, were tested for cytotoxic activity. The root extracts strongly reduced cell growth of tumor cells in vitro, a result consistent with the knowledge of the application of these plant extracts in traditional medicine, especially to cure/ameliorate cancer. A selection of pure diterpenoids existing in extracts from Jatropha species and isolated from J. curcas, for example, curcusone C, curcusone D, multidione, 15-epi-4Z-jatrogrossidentadion, 4Z-jatrogrossidentadion, 4E-jatrogrossidentadion, 2-hydroxyisojatrogrossidion, and 2-epi-hydroxyisojatrogrossidion, were likewise tested, and they also showed strong cytotoxic activity. It turned out that these extracts are highly active against L5178y mouse lymphoma cells and HeLa human cervix carcinoma cells, while they cause none or only very low activity against neuronal cell, for example, PC12. These data underscore that extracts from J. curcas or pure secondary metabolites from the plant are promising candidates to be anticancer drug, combined with low neuroactive effects.

Spirocurcasone, a diterpenoid with a novel carbon skeleton from Jatropha curcas.

Spirocurcasone (14), a diterpenoid possessing the unprecedented "spirorhamnofolane" skeleton, was isolated from the root barks of Jatropha curcas, a plant extensively cultivated throughout the world, along with 11 known and two other new diterpenoids. The stereostructure of spirocurcasone was established using HRESIMS, NMR, and quantum mechanical calculation of the electronic circular dichroic (ECD) spectrum. Some of the isolated diterpenoids showed a potent activity against L5178Y, a mouse lymphoma cell line.

Chemical composition, toxicity and larvicidal activity of the essential oil from the whole plant of Acalypha segetalis from south-west Nigeria.

The chemical composition of the essential oil from the whole plant of Acalypha segetalis Muell. Arg. was analyzed by GC and GC/MS. Nineteen volatile constituents were identified. The main compounds were alpha-pinene (8.5%), neophytadiene, isomer II (14.7%) and neophytadiene, isomer III (33.6%). Toxicity and larvicidal assays revealed that the plant had LC50 values of 14.0 microg/mL and 45.4 microg/mL respectively.

Antibacterial diterpenoids from Jatropha podagrica Hook.

Japodagrin (1) and japodagrone (2), two macrocylic diterpenoids possessing lathyrane and jatrophane skeletons, respectively, have been isolated from the root of Jatropha podagrica Hook. Four other diterpenoids (3-6) were also isolated from this plant. The structures of these compounds were elucidated on the basis of NMR and HRMS analysis, and by spectral comparisons. The compounds displayed antibacterial activity against some gram-positive bacteria.