Organic Chemistry

Essential oils have been used in cuisine as spices or herbs as well as in fragrance, cosmetics, and medicine since ancient times. Although their primary usage in the nineteenth century was as additives for scent and flavor, their original application was in medicine. In this study, essential oil was extracted from fresh leaves of Lantana camara using hydro-distillation procedure. The yield of the oil obtained was 12.68g which represented a 2.54% yield. Gas Chromatography -Mass Spectrometry Analysis of the oil revealed that the essential oil from Lantana camara contains total of 76 compounds representing 99.40% of the oil with (E)- Caryophyllene as the predominant compound in the oil extract constituting 20.6%. The total flavonoid was determined as well as the Total Antioxidant Capacity (TAC) of the essential oil extract of the Lantana camara was examined using UV-Vis spectrophotometer according to the phosphomolybdenum assay. Also, the free radical scavenging activity of the essential oil extract was then determined using the DPPH assay. A comparison of the total phenolic content (TPC) and the total antioxidant capacity (TAC) of the oil extract indicated a slight difference in activity of the TAC than the TPC, meaning there are more phenolic contents present in the oil extract, with a lower antioxidant capacity. Its (Lantana camara) widespread usage as a medicinal plant with the curative effect against a variety of diseases and conditions is supported by the presence of antioxidant qualities in the essential oil.

Cocoa pod husk (CPH), is a rich source of minerals (particularly potassium), fiber (including lignin, cellulose, hemicellulose, and pectin), and antioxidants (e.g. phenolic acids). It is composed of mesocarp, endocarp, and epicarp. The mesocarp consists of fiber (crude, NDF, and ADF-44-48%) and cellulose (53%). CPH’s potential application to human health includes antioxidant, anti-inflammatory, anti-carcinogenic, immunomodulatory, vasodilatory analgesic, and antimicrobial activities. Fresh ripe cocoa pod husks were collected, and the mesocarp was separated and air dried followed by size reduction and extraction with acetone: methanol (7:3) (v/v) using the maceration process. GC-MS analysis was carried out to identify the phytochemical compounds present in the extract. The compounds identified in the extract highlight the great potential of the extract to improve life. When tested, the extract showed activity against nine different human pathogens at varying concentrations. Free radical scavenging activity was also determined using ABTS and DPPH assays, and the extract was found to be potent.

In this research we synthesized yellow colored salen ligand from the condensation reaction of ethylenediamine and salicylaldehyde in absolute ethanol. After this, we synthesized salen and thiocyanate bridging ligand complexes of transition metals including Co(II), Fe(III), Cu(II) and Mn(II). Synthesized compounds were characterized with application of IR, Uv/Vis spectroscopy and cyclic voltammetry and conductivity. Presence of a sharp pick near to 2000cm^-1 supports coordination of thiocyanate ligand to metal center. Shifts in Ir spectra of complexes compared with free ligand refres to coordination on salen ligand to metals via O and N dentates. As a result of ligand coordination to metals, shifts and absorption magnitude in UV/Vis spectra of complexes in the comparison with ligand can be observed. Conductivity measurements revealed that some complexes are ionic compounds. CV characterizations showed that the compounds have reversible and irreversible behaviors.

Various ethyl-2-(2- substituted phenyl hydrazono)-3-oxobutyrate (2a-h) condensation with isonicotinyl hydrazide (i.e. isoniazide) (3) to 1-isonicotinoyl-3-methyl-4-(2-substituted phenylhydrazono)-1H-pyrazol-5(4H)-one (4a-h). The structures of all these compounds (4a-h) were recognized on basis of analytical and spectral data. The newly synthesized compounds were evaluated for their antimicrobial activity against various bacteria and fungi.

Pulverized fruits (500g) of Lantana camara on hydrodistillation, afforded oil in the yield of 0.4% (v/w). Analysis of the oil using GC and GC-MS showed that the bulk of the oil is characterized by the abundance of sesquiterpenoids (91.9%). The percentage composition of monoterpenoids in the oil was 7.1%, while phenylpropernoids were detected in trace amounts. The principal constituents of the oil were; germacrene D (38.1%), germacrene-D-4-ol (19.6%), ?-caryophyllene (17.7%) and germacrene B (16.5%). The abundance of germacrene D in the oil shows that the oil is of germacrene D chemotype.

The adsorption characteristics of Georgian natural and acid-modified forms of clinoptilolite and laumontite have been studied in order to determine possibilities of their application in treatment of water contaminated by metals. It was found that natural clinoptilolite washed by diluted acid is the most effective adsorbent for barium, cobalt and lithium, while strontium, manganese, nickel and lead can be captured by modified clinoptilolite, but zinc, iron and copper – by modified laumontite. A combined filter (quartz sand + washed clinoptilolite + laumontite + clinoptilolite, both treated with 1.0N HCl solution) is offered.

The fungus X. badia was cultured on 3% aqueous malt enriched with 6% glucose in ten Thompson bottles for eight weeks. Solvent extraction with ethyl acetate and subsequent drying on a rotary evaporator, afforded a dark brown gummy solid (5.0 g). TLC studies indicated that the crude extract was a mixture of four components. The dark brown gum was chromatographed over silica gel in a column of size 80 cm x 2.5 cm. The column was eluted with toluene, ethyl acetate and acetic acid (50:49:1) and the eluent collected in volumes of 3.0 ml. Fraction 3 gave a yellowish oil (150 mg). The oil was triturated with n-hexane to give a white powdery solid (12 mg). The solid was recrystallized from the same solvent system, yielding white crystals (8 mg). Spectroscopic analysis of this compound indicated that it is R- mellein. This is the first report of this secondary metabolite from Xylaria badia.

This work aims to evaluate the effects of current density and plating time on the corrosion resistance of ZnNiSiO2 electroplated coating. For the plating time, the results showed that coating thickness increased with increasing the plating time. The average thickness was 6, 15 and 25 µm, when used plating time of 10, 30 and 50 minutes, respectively.Whereas, when the current density values varied from 1 A/dm2 to 5 A/dm2, the coating thickness was in range of 14.7 - 15.3 µm, with the same plating times. After 900 hours of exposure to salt spray, the surface appearance of coatings indicated that the plating time of 30 minutes provided the highest corrosion resistance. These data were coherent with the findings from polarization curve measurement.

Mangrove plants and their associated micro fauna have been a rich source of bioactive secondary metabolites, though only limited antimicrobial screening of this chemo-diversity source has been reported. In this study, unidentified endophytic fungi BBMS and BBMAV were isolate from the bark of black mangroves obtained from the coastal forest of Ayensu estuary. The endophytes were cultured in static medium made of 3%(w/v) malt concentrate and 6%(w/v) glucose in distilled water. The fungi were cultured for 8 weeks and harvested. Ethyl acetate extraction of the filtrate followed by drying on a rotary evaporator afforded 1.20 g and 1.05 g of BBMS and BBMAS respectively. TLC studies and GC-MS analysis indicated that the extracts contained interesting secondary metabolites. A bioassay of the extracts was carried out on human pathogen and cocoa infesting microbes. The bioassay results indicated that the extracts were active against all the test organisms. ABTS and DDPH free radicals scavenging activities were also tested with the extracts. The results indicate that the extracts of the fungal isolates exhibited high potency of antioxidant activity.

Cytochalasin D is a cytotoxic compound used in cellular research and drug development. Cytochalasin D is produced from molds, often in mixtures which are difficult to purify. Yields from the synthesis of the compound are poor, hence the high cost of the cytotoxic compound. Static cultures of a group of endophytic fungi: were sub-cultured in 250 ml conical flask each for three weeks. Each of the endophyte culture was transferred into ten 2.0 dm3 Thompson bottles and allowed to grow for 8 weeks. TLC studies of the individual crude extracts indicated that the four mangrove endophytes produced the same compounds. The crude extract obtained from RAR 5-6 was dissolved in warm ethyl acetate and left overnight. A white solid (0.90 g) precipitated from the solution. The solid was removed by filtration and recrystallized from the same solvent to give pure cytochalasin D. The resulting filtrate was chromatographed on silica gel. Fraction 5 yielded a yellow viscous liquid (270 mg). This was triturated with alcohol and left to stand for 48 h to give white crystals, Spectroscopic analysis indicated that the compound was 5-carboxymellein. The production of pure cytochalasin D from these endophytic fungi could be a source of commercial production of this important cytotoxic compound.