Latest Research In Chemical Composition
Chemical Composition and Antimicrobial Activity of Flower Essential Oil of Jacaranda acutifolia Juss. against Food-Borne Pathogens
Aims: To investigate the chemical composition and antimicrobial activity of the hydrodistilled flower essential oil of Jacaranda acutifolia Juss. (Bignoniaceae) to validate some of its ethnopharmacologial uses such as treatment of wounds and dermatitis.
Study Design: Volatile oil isolation, component identification and antimicrobial activity.
Place and Duration of Study: Faculty of Pharmacy, Ain Shams University, and the flowers were collected on 15 April 2012 and the study is completed within four months.
Methodology: The essential oil of the flowers of Jacaranda acutifolia was extracted by hydrodistillation, analysed by capillary gas chromatography (GC/FID) and gas chromatography–mass spectrometry (GC/MS). Antimicrobial activity was studied in vitro; this included both antibacterial activity against food-borne pathogens and antifungal activity using agar diffusion method.
Results: Forty six components, comprising almost 81.36 of the total peak area, were identified in the analysis. The main components were n-dodecanoic acid (17.48%), n-tetradecanoic acid (15.59%), n-hexadecanoic acid (10.98%), hexahydrofarnesyl acetone (8.2%), n-decanoic acid (7.9%), and nonacosane (7.71%). According to the observed inhibition zone, which ranged from 13 to 26.5 mm, the oil showed significantly high in-vitro antimicrobial activity against Staphylococcus aureus, Escherichia coli and Candida albicans with minimum inhibitory concentration (MIC) values ranging from 0.09 up to 1.09 mg/ml, and moderate antimicrobial activity against Salmonella typhimurium andShigella flexneri. The potency of the oil was calculated as compared to standard antibiotics, and 1 mg oil was equivalent to 1.05 µg penicillin against S. aureus; 2.72 µg nystatin against C. albicans; 13.55, 1.3 and 272 µg gentamicin against E. coli, Samonella and Shigella species respectively.
Conclusion: The essential oil of Jacaranda acutifolia exhibited promising antimicrobial activity, and this makes its local traditional uses rational.
Variability in the Chemical Composition of Essential Oil Derived from Ocimum basilicum L. var. Minimum over Several Months
Ocimum basilicum L. (‘licorice’ variety) is a plant commonly known as albahaca or basil that is used in a variety of industries around the world. The variability in the chemical composition of the essential oil derived from this plant, gathered in different growing months, is reported herein. The aerial parts, those parts exposed to the air, of O. basilicum L. yielded an average of 0.3% ± 0.25% of the essential oil in the four month period of the evaluation.
Using GC-MS analysis, 107 components were detected in the essential oil, 102 of them were identified (95.3%) and 15 showed a greater than 1% relative yield. Estragol, at 40.6%, and linalool, at 17.8%, were the most important components of the essential oil.
According to the refractive index (1.5230), the essential oil could be classified into the Reunion Type. Based on the relative percentage of the two most important components, estragol and linalool, the essential oil could be classified as European Type 1, and considering the possible chemo type based on the percentage of estragol, the classification corresponded to the BA Type.
This is the first time that an evaluation of the changing chemical composition of the essential oil derived from O. basilicum over four consecutive months has been published.
Chemical Composition of Essential Oils of Plumeria rubra L. Grown in Nigeria
The chemical compositions of essential oils obtained by hydrodistillation of the leaves and flowers of pink-flower Plumeria rubra L., grown in Nigeria were being reported. The chemical analysis was performed by means of gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS) techniques. The major leaves oil constituents were (Z)-β-farnesene (16.0%), α-patchoulene (13.0%), limonene (12.1%), (E)-β-farnesene (10.8%), α-copaene (7.2%) and phytol (6.3%). However, the quantitative significant compounds of the flowers oil were (E)-non-2-en-1-ol (15.7%), limonene (10.8%), phenyl acetaldehyde (9.0%), n-tetradecanal (8.8%), γ-elemene (6.5%) and (E,E)-α-farnesene (6.1%). This is the first report on the volatile constituents from the leaves of Plumeria rubra.
Aims: The aim of the of the present study was to examine the constituents of the leaves and flowers oils of P. rubra grown in Southwest Nigeria in details, and to compare the results obtained with those reported earlier.
Study Design: Isolation of essential oils from the leaves and flowers of Plumeria rubra and determination of their chemical constituents.
Place and Duration of Study: Fresh plant materials of P. rubra (flowers and leaves) were collected from a location within the Campus of Lagos State University, Ojo, Lagos State, Nigeria, in October 2013.
Methodology: Fresh leaves and flowers were hydodistilled in an all glass Clevenger apparatus and their chemical constituents were analyzed by GC and GC/MS.
Results: A total of twenty six compounds were identified in the leaves and the major ones were (Z)-β-farnesene (16.0%), α-patchoulene (13.0%), limonene (12.1%), (E)-β-farnesene (10.8%), α-copaene (7.2%) and phytol (6.3%) while the flowers had twenty seven compounds with (E)-non-2-en-1-ol (15.7%), limonene (10.8%), phenyl acetaldehyde (9.0%) and n-tetradecanal (8.8%) occurring in higher percentages.
Conclusion: The chemical composition of the volatile compounds differed from each other and from data reported previously from other parts of the world.
CHEMICAL COMPOSITION OF ESSENTIAL OILS FROM THE OLEORESIN OF Pistacia atlantica Desf FROM ALGERIA
The chemical composition of the three essential oils of Pistacia atlantica Desf resin collected from different localities from the west and south-west of Algeria (Sfisef, Saida and Naama localities) were obtained using hydrodistillation and analyzed by GC and GC/MS. Fifty (50) compounds have been identified in these volatile oils. Non-oxygenated monoterpenes were the predominant group of constituents in the essential oils. The most representative monoterpenes hydrocarbons identified in the three localities samples respectively were α-pinene (79.8%, 65.3% and 25.4%) and β-pinene (7.4%, 16.52% and 3.0%).
ON FLUCTUATIONS IN THE CHEMICAL COMPOSITION OF THE COARSE PRIMARY M7C3 CARBIDES IN AISI D2 TOOL STEEL
Changes and fluctuations in the chemical composition of the coarse primary M7C3 carbides in tool steels have been one of the Authors’ main task of the studies. The purpose of this study was to supplement the revealed fluctuations in the composition of M7C3 carbides of D2 tool steel after a standard soft annealing and consecutive austenitizing this steel at 1150ºC in the air atmosphere. The study was performed on the decarburized layer, on the depth of about 0.4 mm from the surface. The hardened tool steel samples were soft annealed and then austenitized for the two periods of time: 30 minutes, and 90 minutes. The studies allowed to find the coarse primary M7C3 carbides differ significantly both after annealing and austenitizing. The difference in D2 tool steel relates to the contents of Cr, Mo, and V. The highest differences were found in the contents of chromium and molybdenum. The average concentration of chromium was found to rise successively with the growth of austenitizing time. After first 30 minutes of austenitizing the concentrations of molybdenum and vanadium are lower than these concentrations in the carbides of the annealed D2 tool steel. Prolongation of the austenitizing time to 90 minutes results in lowering the per cent fraction of Mo while that of V increased in the coarse carbides. That unusual behavior of these two elements was also observed in other Authors’ studies on other steels.
It was found that the precipitation of the second phase occurs after the operation of austenitizing of AISI D2 tool steel at the temperature of 1150ºC in the air atmosphere. This second phase appears to be brighter in the BSE_Z pictures, in relation to the matrix of carbides. Moreover, the amount and magnitude of this second phase is getting higher with the rise of annealing time.
PROXIMATE COMPOSITION AND PHYSICO-CHEMICAL PROPERTIES OF THREE AVOCADO (Persea americana) VARIETIES IN UMUAHIA, NIGERIA
Studies were carried out on oil extraction and proximate analysis of pulp and oil from three varieties of ripe avocado (Persea americana) namely; Brogdon, Russel and Choquette. Solvent extraction of oil was done using three different solvents namely; ethanol, hot water and chloroform. The Brogdon variety gave the highest yield and ethanol was the best solvent for extraction. The proximate analysis of the avocado pulp showed that the Brogdon, Russel and Choquette varieties had moisture contents of 67.87, 69.35 and 67.34%, respectively. Ash content was 1.05, 1.00 and 1.07% while crude fibre was 4.65, 4.00 and 4.80% for the Brogdon, Russel and Choquette varieties, respectively. The fat contents are 18.77, 14.67 and 16.27%, respectively and their crude protein content was 2.76%, 2.38% and 2.56% for the Brogdon, Russel and Choquette varieties. The physical and chemical characteristics of the extracted oil were determined. Results showed that the physical characteristics of the oils from the Brogdon, Russel and Choquette varieties were respectively: melting point (21.72, 20.64 and 21.33°C), refractive index (1.43, 1.41 and 1.42), specific gravity (0.91, 0.91 and 0.92), moisture content (1.03, 1.25 and 1.35%), flash point (237.55, 248.00 and 255.44°C) and smoke point (178.89, 181.33 and 187.33°C). The chemical parameters of the Brogdon, Russel and Choquette varieties were; saponification value (181.78, 182.78 and 182.58 mgKOH/g), iodine value (89.48, 90.55 and 90.45 mgKOH/g), acid value (0.83, 0.79 and 0.69 mgKOH/g), free fatty acid (1.58, 1.54 and 1.30%) and peroxide value (3.28, 2.88 and 3.00 mg/kg). The physico-chemical characteristics and proximate composition of the oil shows that it has some industrial potential and utilization of this oil will reduce dependence on the popular vegetable oils like groundnut, coconut and palm oil for domestic use.