Micromorphological, anti-nociceptive and antiinflammatory investigations of stem bark of Daniellia oliveri

Anatomical and powdered samples of stem bark of Daniellia oliveri were investigated for its micromorphological profile, while the aqueous extract was investigated for its anti-nociceptive and antiinflammatory effects in mice and rats, respectively. The micromorphological study indicated the presence of characteristic bundles of phloem tissues, separated by medullary rays, abundant grains of starch in isodiametric parenchyma cells, prisms of calcium oxalate crystals, cork cells and cortex parenchyma. The extract showed a significant anti-nociceptive activity at the tested doses (50, 100, 200 mg/kg i.p.). The extract at the same doses showed a non-dose dependent anti-inflammatory activity. The effect was significant at doses of 100 and 200 mg/kg. These findings contribute to the preparation of a monograph for proper identification of the plant and also corroborate some of the traditional use

Comparative analgesic activity of the root bark, stem bark, leaves, fruits and seeds of Carissa edulis VAHL (Apocynaceae)

The analgesic activity of the water extracts (50,100 and150 mg/Kg body weight) of the root bark, stem bark, leaves, fruits and seeds of Carissa edulis were evaluated in mice using the mechanical method(tail-chip method) and chemical method (acetic acid induced writhing). The plant was found to have analgesic activity, with the fruits having the highest activity, followed by the leaves, seeds, root barkand stem bark respectively using metamizol as standard with mechanical method. There was slight variation with chemical method, the seeds were found to be most effective followed by fruits, leaves, root bark and stem bark respectively using acetylsalicylic acid as standard. The analgesic activity compared well with metamizol and aspirin which were used as standard, the chromatographic analysis indicate the presences of salicylates. These result justified the use of the plant in the treatment of toothache, lumbago, oedema and chest complaints by the traditional medical practitioners

Post-polymerisation modification of poly(3-hydroxybutyrate) (PHB) using thiol–ene and phosphine addition

As we face the issues associated with fossil resource-based polymers and their environmental impact after their useful life, polyesters become more important as “greener” alternatives due to their potential hydrolytic and enzymatic degradability in various environments. Moreover, post-modifying their structure can additionally open up access to a variety of new materials. During this work the potential to post-modifying synthetic PHB made via the organocatalysed ring-opening polymerisation of β-butyrolactone (β-BL) is shown. Modification by thiol–ene ‘click’ chemistry was succesfully conducted under UV-initiation. Surprisingly, attempting the modification under thermal conditions using dimethylphenylphosphine (DMPP) as catalyst, resulted in the attachment of the phosphine, as shown via NMR spectroscopy. Control experiments using crotonic acid, methyl crotonate and n-butyric acid indicated that the presence of a carboxylic acid group is necessary in order for the phosphine addition to occur. Further, the formation of particles shown via dynamic light scattering (DLS), zeta-potential (ZP) and transmission electron microscopy (TEM) measurements suggest an amphiphilic character of the phosphine-functionalised polymers. Finally, stability studies in the presence of salt and different pH environments revealed a high responsiveness and dependency between pH and particle size as well as surface charge

Functional pH-responsive polymers containing dynamic enaminone linkages for the release of active organic amines

Dynamic covalent bonds have attracted considerable attention for the development of pH-responsive polymers, however, studies using acid-cleavable enaminone linkages as a means of controlled release are limited. Herein, we report pH-sensitive benzocaine-modified poly(ethylene glycol) monomethyl ether-block-poly[2-(acetoacetoxy)ethyl methacrylate] (mPEGx-b-pAEMAy)/BNZ nanoparticles (NPs) for the aqueous controlled release of benzocaine through enaminone bond cleavage. The system is based on the commercially available monomer 2-(acetoacetoxy)ethyl methacrylate (AEMA) which contains free pendant β-ketoester functionality. Well-defined poly[2-(acetoacetoxy)ethyl methacrylate] (pAEMA) homopolymers and poly[(ethylene glycol) monomethyl ether]-block-poly[2-(acetoacetoxy)ethyl methacrylate] (mPEGx-b-pAEMAy) amphiphilic block copolymers were prepared by photoinduced Cu(II)-mediated RDRP to investigate their modification with propylamine (a model amine) and benzocaine (a primary amine containing API) through an enaminone bond. Block copolymers were prepared via two poly(ethylene glycol) monomethyl ether-2-bromo-2-phenylacetate (mPEGx-BPA, x = 43 or 113) macroinitiators synthesised by esterification which acted as the hydrophilic coronas of the ensuing NPs. The self-assembly of both mPEGx-b-pAEMAy and (mPEGx-b-pAEMAy)/BNZ was assessed in water by the direct dilution approach forming spherical NPs as characterised by dynamic light scattering (DLS) and dry-state transmission electron microscopy (TEM). Finally, the in vitro controlled release of benzocaine from mPEGx-b-pAEMAy/BNZ NPs was examined at different pH environments demonstrating faster release kinetics at lower pH with potential utility in applications with relevant chemical environments

Well-defined polyacrylamides with AIE properties via rapid Cu-mediated living radical polymerization in aqueous solution : thermoresponsive nanoparticles for bioimaging

There is a requirement for the development of methods for the preparation of well-controlled polymers with aggregation-induced emission (AIE) properties. This requirement directed this current work towards a robust synthetic route, which would be applicable for preparation in water and the presence of many types of functional groups. Herein, aqueous Cu-mediated living radical polymerization (LRP) has been optimized to provide facile and rapid access to a diverse range of water-soluble AIE polymers at sub-ambient temperatures. Homo-, block and statistical copolymerization all proceeded to a near full monomer conversion (≥99%) within 1 or 2 h and exhibited narrow dispersity, even when DP was targeted up to 1000. This excellent control associated with this polymerisation technique and the high-end group fidelity achieved were further demonstrated by linear first order kinetics and successful in situ block copolymerization, respectively. Fine-tuning the monomer sequence and composition of poly(N-isopropylacrylamide) (PNIPAM) copolymers allows for different lower critical solution temperature (LCST) and fluorescent thermoresponsive nanoparticles, which spontaneously self-assembled to varying sizes in water as determined by a combination of techniques (DLS, SAXS and TEM). Additionally, the fluorescence intensity was demonstrated to depend on the polymer concentration, architecture of the side chains and temperature. Particularly, PNIPAM-containing polymers were resistant to reduction in thermo-induced emission. The good biocompatibility, photostability and high specificity make them promising candidates as lysosome-specific probes for application in bioimaging

Heterotelechelic homopolymers mimicking high χ – ultralow N block copolymers with sub-2 nm domain size

Three fluorinated, hydrophobic initiators have been utilised for the synthesis of low molecular mass fluoro-poly(acrylic acid) heterotelechelic homopolymers to mimic high chi (χ)–low N diblock copolymers with ultrafine domains of sub-2 nm length scale. Polymers were obtained by a simple photoinduced copper(II)-mediated reversible-deactivation radical polymerisation (Cu-RDRP) affording low molecular mass (<3 kDa) and low dispersity (Đ = 1.04–1.21) homopolymers. Heating/cooling ramps were performed on bulk samples (ca. 250 μm thick) to obtain thermodynamically stable nanomorpologies of lamellar (LAM) or hexagonally packed cylinders (HEX), as deduced by small-angle X-ray scattering (SAXS). Construction of the experimental phase diagram alongside a detailed theoretical model demonstrated typical rod–coil block copolymer phase behaviour for these fluoro-poly(acrylic acid) homopolymers, where the fluorinated initiator-derived segment acts as a rod and the poly(acrylic acid) as a coil. This work reveals that these telechelic homopolymers mimic high χ-ultralow N diblock copolymers and enables reproducible targeting of nanomorphologies with incredibly small, tunable domain size

CARDIO-ACTIVITY OF SARMENTOSIDE-A FROM STROPHANTHUS SARMENTOSUS SEEDS

Sarmentoside-A extracted from the seeds of Strophanthus sarmentosus was tested on rabbit heart preparation. Its cardio active property compared favourably with digoxin. Both drugs (Sarmetoside-A and digoxin) increased the force and rate heart contractions; these effects were antagonized by potassium chloride solution. Key Words: Sarmentoside-A, Strophanthus sarmentosus, cardioactivity Nig. J. Nat. Prod. And Med. Vol.1 1997: 16-1

Extraction and characterization of mucilage from Crotalaria senegalensis Linn (Family – Fabaceae)

Mucilages from the leaves, stem and root of Crotalaria senegalensis Linn. (Fam. Fabaceae) has been extracted using both the cold and hot extraction methods. The results obtained showed that the hot extraction method (HEM) is a better extraction method than the cold extraction method (CEM) as the yields were:- 10.2%; 5.9% and 1.2% w/w (HEM) as opposed to: 8.0%; 3.7% and 1.0% w/w (CEM) for the leaves, stem and root respectively. Characterization of the mucilage showed that it is composed of galacturonic acid, fructose, arabinose, galactose and xylose. The elemental analysis indicated the presence of magnesium. Key words: Crotalaria senegalensis; Mucilage; Extraction; Characterization Nig. J. Pharm. Res. 3(1) 2004: 106-10

PHARMACOGNOSITIC STUDIES OF THE LEAF AND STEMBARK OF STEGANOTAENIA ARALIACEAE HOCHST

Microscopical investigation of the powdered leaves and stembark of Steganotaenia araliaceae (family Umbelliferae) shows the presence of anisocytic stomata, calcium oxalates, secretory cells and fibres in the leaves and cork cell, aleurone grains in the stembark. The fresh parts also showed diagnostic palisade ratio and stomata number. Key Words: Steganotaenia araliaceae, Microscopy, pharmacognostic data Nig. J. Nat Prod. And Med. Vol.3 1999: 61-6

ALKALOIDAL COMPOSITION AND TOXICITY STUDIES OF THREE NIGERIAN CROTALARIA SPECIES

The study of the alkaloids of three Crotalaria species was carried out with special reference to their toxicity. These are Crotalaria microcarpa Hochst: Crotalaria naragutensis, Hutch. and Crotalaria retusa L. Alkaloids was detected in the leaves and aerial parts of all the three species except the leaves of C. naragutensis. Mattock's test for unsaturated pyrrolizidine alkaloids (hepatotoxic) revealed that only C. retusa contained these alkaloids amongst the three species. This indicated that this is a potentially toxic specie. The alkaloids of C. retusa were toxic to albino (Wistar) rats. Marked microscopic lesions were found, principally in the liver. The lungs, kidneys and intestine also had significant toxic features. Toxicity pattern was typical of the alkaloid monocrotaline. Key Words: Crotalaria; pyrrolizidine alkaloids; toxic plants, necrosis, hyperaemia. Nig. J. Nat Prod. And Med. Vol.4 2000: 43-4