Gabriel A. Olatunji

Production and characterization of biodiesel using palm kernel oil; fresh and recovered from spent bleaching earth

Palm kernel oil (PKO) was recovered from spent bleaching earth with a yield of 16 %, using n-hexane while the fresh oil was extracted from palm kernel with n-hexane and a yield of 40.23% was obtained. These oils were trans-esterified with methanol under the same reaction conditions: 100 oC, 2 h reaction time, and oil-methanol ratio of 5:1 (w/v). The cocoa pod ash (CPA) was compared with potassium hydroxide (KOH) as catalyst. The percentage yields of biodiesel obtained from PKO catalysed by CPA and KOH were 94 and 90%, respectively. While the yields achieved using the recovered oil catalysed by CPA and KOH were measured at 86 and 81.20 %. The physico-chemical properties of the biodiesel produced showed that the flash point, viscosity, density, ash content, percentage carbon content, specific gravity and the acid value fell within American Society for Testing and Materials (ASTM) specifications for biodiesel. The findings of this study suggest that agricultural residues such as CPA used in this study could be explored as alternatives for KOH catalyst for biodiesel production.

Antioxidant and Cytotoxicity of β-Amyrin acetate fraction from Bridelia ferruginea Leaves

Abstract Objective The objective of this work was to determine the beta-amyrin acetate fraction in leave extract of Bridelia ferruginea and evaluate for its antioxidant and cytotoxicity potentials. Methods The dried and pulverized leaves of Bridelia ferruginea was extracted with hexane and then with ethyl acetate. The concentrated ethylacetate extract subjected to silica gel column chromatography and eluted with a mixture of equal volume of hexane and dichloromethane afforded two major fractions. The more polar fraction was concentrated and subjected to GCMS analysis which afforded the steroid, 12-Oleanen-3yl acetate commonly known as beta-amyrin acetate (66.14%). Its ability to act as a scavenger of DPPH radical and its cytotoxicity potential based on brine shrimp assay were investigated. Results The DPPH antioxidant assay revealed that the fraction had a higher antioxidant potential with an IC 50 value of 158.2μg/mL relative to gallic acid which had IC 50 of 201.1 μg/mL. The cytotoxicity assay using the brine shrimp a gave LC 50 values of 319 and 5.86 μg/mL for acute and lethal doses respectively indicating extreme toxicity when compared to reference drug, cyclophosphamide which had LC 50 value of 2506 μg/mL. Conclusions Thus, the beta-amyrin acetate has been identified for the first time in the leave of Bridelia ferruginea. The data here suggest that the beta-amyrin acetate fraction of the leave of Bridelia ferruginea could be further explored in biological profiling requiring antioxidant and cytotoxic dependent therapeutics as the plant could be a viable source of antioxidant and cytotoxic agents in cancer chemotherapy in the near future.

Chemical composition and antioxidant potentials of Kigelia pinnata root oil and extracts

The chemical composition of Kigelia pinnata root oil extracted with n-hexane was analyzed by GC/GCMS. The antioxidant potential of the oil was compared to that of ethyl acetate and methanol extracts of the root. UV and IR spectroscopic techniques were used to carry out partial characterization of the oil and extracts. The free radical scavenging activity by spectrophotometric assay on the reduction of 1,1-diphenyl-2-picrylhydrazyl (DPPH) was examined while the total antioxidant activity (TAA) and relative antioxidant activity (RAA) were compared with standard antioxidant, α-tocopherol. The antioxidant activity (which correlated with the total phenolic content of the extracts) was assumed to be from the total phenolic content of the extracts. TAA was found to be higher in methanol extract (at 0.25 mg/mL). We hereby report for the first time the major component of the oil from the root of Kigelia pinnata to be elaidic acid (56.12 %). It is a reported toxicant which thereby underscores the risk in the use of the plant in traditional therapies.

Acetylation of Wood Flour from Four Wood Species Grown in Nigeria Using Vinegar and Acetic Anhydride

Effect of acetylation on pretreated wood flour of four different wood species, Boabab (Adansonia digitata), Mahoganny (Daniella oliveri), African locust bean (Parkia biglobosa) and Beech wood (Gmelina arborea), had been investigated. The first batch of wood species were acetylated using acetic anhydride while the second batch were acetylated with commercial vinegar. Both experiments were conducted in the presence of varying amount of CaCl2 as catalyst and at temperature of 120°C for 3 h. The success of acetylation was determined based on Weight Percent Gain for each sample treated with either chemicals used. FT-IR, a veritable tool was used for the analysis of both treated and untreated samples to further investigate the success of acetylation. The results showed the presence of important band such as carbonyl absorptions at 1743, 1744, 1746, 1731, 1718 and 1696 cm−1 as appeared separately in the spectra of acetylated samples, confirming esterification occurred. The purpose of this work was to investigate the applicability of vinegar for acetylation of lignocellulosic fibers. Blends/composites were prepared by solution casting and their kinetics investigated in distilled water. The results indicated they could be used in outdoor applications such as, decking and packaging.

Phytochemicals from Kigelia pinnata Leaves Show Antioxidant and Anticancer Potential on Human Cancer Cell Line

Studies suggest that the traditional applications of Kigelia pinnata leaves have beneficial effects against oxidative stress-mediated diseases and cancers. The pulverized dried leaves of K. pinnata were extracted with hexane, ethyl acetate, and methanol sequentially, and the crude extracts were fractionated by silica gel column chromatography with solvent gradient of increasing polarity. 3-hydro-4,8-phytene, trans-phytol, (9Z,12Z)-methyl octadeca-9,12-dienoate, and two oil fractions were obtained. The chemical compositions of chromatographic fractions were determined using gas chromatography-mass spectroscopy. The structure elucidations of the isolated compounds were based on FTIR, MS, and NMR spectral data analyses. These along with the crude extracts were examined for their antioxidant activities using ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, and 2,2-azinobis(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) assays. Total phenolic contents were also determined. The crude extracts and purified compounds were evaluated on the rhabdomyosarcoma human cancer cell for their cytotoxicity using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell viability assays. The methanol extract was richer in phenolics and was most potent as antioxidant and cytotoxic agent among all the substances tested. Among the fractions and pure compounds, the two oil fractions showed more cytotoxicity potency, with IC50s of 143.4±0.5 and 147.9±1.3 ng/mL, which is more significant than the reference standard, cyclophosphamide (165.6±1.0 ng/mL). 3-hydro-4,8-phytene showed lower antioxidant and cytotoxicity potential (IC50=1818±5.2 μg/mL and 171.7±0.8 ng/mL, respectively). Trans-phytol did not show a high cytotoxic power (IC50=769.8±4.3 ng/mL). The comparatively high cytotoxicity index of (9Z, 12Z)-methyl octadeca-9,12-dienoate (IC50=153.3±0.1 ng/mL) indicated that it may be one of the principal cytotoxic agent in the ethyl acetate extract. These results suggest that the leaves of K. pinnata possess tumor cytotoxic potential and could be part of a drug combination for future cancer chemotherapy.

A STUDY OF THE THERMAL DECOMPOSITION OF SOME TRIPHENYLTIN CARBOXYLATES

Abstract The thermal behaviour of some triphenyltin carboxylates has been studied by means of thermogravimetry (TG), differential thermal analysis (DTA), and mass spectrometry. The melting point enthalpies have been determined by means of DTA and found to vary from 17 to 37 kJ mole −1 . No distinguishable decarboxylation process is observed, rather the compounds decompose gradually to yield tin(IV) oxide as the final product. Analysis of the mass spectra of the decomposition products suggests that a phenyl radical is first cleaved, resulting in the formation of a diphenyltin complex with SnO bridging. Successive cleavage finally leaves Sn as the final product.

Scanning Electron Microscopy and Kinetic Studies of Ketene-Acetylated Wood/Cellulose High-Density Polyethylene Blends

Acetylated cellulose and wood cellulose as well as untreated cellulose polyethylene blends were subjected to kinetic studies using water, 0.5 M NaOH, and 0.5 M HCl solutions in order to investigate their absorbent properties at 0.5/1.0 cellulose/wood cellulose/polyethylene matrix. The results of the absorption studies showed that the untreated cellulose and wood cellulose blends absorbed water and the acid and alkali solutions higher than the treated samples, which showed a reduction in acid, alkali, and water uptake. In this work, the effects of acetylation on the morphological studies of the polyethylene blends were obvious. The presence of acetyl groups improved the interfacial bonding between the polymer matrix and cellulose as well as the wood cellulose fibers, as evidenced by scanning electron microscopy (SEM).

Natural antifungal compounds from the peels of Ipomoea batatas Lam

Abstract Three antifungal compounds have been isolated for the first time from the peels of Ipomoea batatas Lam. Their structures were established on the basis of 1D and 2D NMR spectra data as well as ESI-MS and IR analysis. Urs-13(18)-ene-3β-yl acetate was found to possess a weak activity against Sporothrix schenckii and Trichophyton metagrophytes fungi with an MIC value of 50 μg/mL each. Stigmasterol and 3-friedelanol were equally active against T. metagrophytes.

Energy Dispersive - XRF Metal Analysis and Cancer Cell Line Cytotoxicity of Kigelia pinnata Root

Human exposure to heavy metals is attributed to consumption of herbs grown in polluted environment. The objective of this study was to assess the health risks associated with metals toxicity in Kigelia pinnata root and also evaluate the cytotoxic potential of the root on rhabdomyosarcoma, RD cancer cell line. Energy dispersive X-Ray Fluorescence, ED-XRF was employed for the assessment of the total metal profile of the root while the hexane, ethylacetate and methanol extracts of the root obtained through exhaustive sequential extraction were evaluated on the RD cancer cell line for its cytotoxicity index using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide, MTT cell viability assay. All the extracts showed high cytotoxicity. However, ethylacetate extract (IC50, 142.2 ± 1.1 ng/mL) showed the highest activity compared to the reference drug, cyclophosphomide (IC50, 165.6 ± 1.0 ng/mL). Heavy metal concentrations in the root of plant grown in the forest did not exceed the permissible limits set by the EU regulatory body. The health risk index of the root of plant is considered relatively safe for therapeutic purposes. With regards to metal toxicity, the study indicated that there is a relative absence of health risks associated with the ingestion of Kigelia pinnta root extracts while administering for treatment of cancer related diseases in traditional medicine. The root extracts could serve as a basis for development of disease-oriented drugs or nutraceuticals. There is however a need for caution since iron concentration is high.

Isolation and evaluation of antiglycation potential of polyalthic acid (furano-terpene) from Daniella oliveri

A furano-diterpene (polyalthic acid) was isolated as a major stable compound for the first time from the oleoresin of the Daniella oliveri of the family Caesalpiniacea through column chromatography fractionation. Polyalthic acid was characterized using data obtained from EIMS, HREIMS, ESI-MS, MALDI-MS as well as 1D and 2D NMR and it was evaluated for its potential to inhibit the formation of advanced glycation end-products (AGEs) using a standard in vitro antiglycation procedure. Polyalthic acid indicated a negative antiglycation potential compared to standard inhibitor that has 85% inhibition, which is an indication that polyalthic acid may not contribute to the antiglycation activity of the plant as acclaimed in folkloric medicine. The negative antiglycation observed could indicate that the polyalthic acid could trigger glycation, thereby subjecting users to various degrees of complications. The bioactivity evaluation on molinspiration evaluator indicated that polyalthic acid could be a potential drug candidate. The biological and chemical insights gained on polyalthic acid provide a good basis for future research.