Essential oils are composed of a wide range of bioactive chemical compounds. They traditionally found application as flavour, fragrances and medicinal aroma. Today, the essential oils are sought-after for innumerable applications starting from markers for plant identifications to base for semi-synthesis of highly complex molecules. The extraction of highly delicate essential oils from plants remains a crucial step in all these applications. By using microwaves to mediate the extraction, it is possible to maintain mild conditions and effect superior extraction. However, apart from laboratory trials, essential oil extraction using microwave energy is largely an unexplored area. In the current work, an integrated procedure for microwave extraction followed by volatiles sampling and analysis from selected botanical raw materials (viz. black pepper, Piper nigrum and coriander Coriandrum sativum) was developed. There are two problems to overcome in the extraction from solid plant materials: that of releasing the essential oil from solid matrix and letting it diffuse out successfully in a manner that can be scaled-up to industrial volumes. Towards this end, an innovative volatiles extraction unit was conceived, designed and developed that used thin layer, for microwave exposure and rotational mixing, to mitigate the effects of thermal gradient and non-uniform exposure of bulk matter. The effect of varying the microwave field on the essential oils extracted was studied. The microwave field that coupled in the region of extraction was estimated from temperature rise measurement using the microwave power equation (with water as reference dielectric). The essential oil extracted under different microwave fields were compared using gas chromatography-mass spectrometry (GC-MS) and data analysis with SAS statistical software. The microwave field at the site of extraction was sensed by symmetrical placement of biomaterial sample and a reference, in a rotational extractor, such that they both couple the same field during tumbling motion. By measuring the temperature rise in the reference accurately, it is possible to estimate the microwave field present at that position. The rotational extractor has a second degree of freedom, in that it can slide along the axel taking discrete positions. Each position leads to a different microwave exposure of the sample. It is possible to measure the relative variation of microwave field using temperature rise data at each position. It was found that, at position labeled R4, located at 65.6 mm from the right extreme of the microwave cavity had the highest effective microwave field strength of value 92.7 V/m. The volatiles released from the biomaterials, black pepper and coriander, were sampled using solid phase micro extraction and analyzed using gas chromatography-mass spectrometry. The highest peaks representing beta-caryophyllene in black pepper and linalool in coriander were identified using mass spectrometric peak matching using NIST library.The extract (in terms of ion count) for each microwave parameter (such as field, water content level and solvent type) was plotted as a trend graph. The current experiment successfully tested the procedure for following the microwave process in the extraction of sensitive spice volatiles (from black pepper and coriander). With the microwave field measured at the region of extraction, it was possible to plot pepper extraction versus the microwave field to which the pepper sample was exposed. The extraction was represented in terms of cumulative value of ion counts obtained in GC-MS analysis. This unique procedure developed in the current research allows for the graphical comparison of the microwave extractions. It was found that black pepper has a better response to microwave extraction than coriander. The pepper extraction was found to increase proportionately with increase in microwave field strength. The extraction was also enhanced proportionately by the incremental addition of water content at constant microwave field.

Essential oils are composed of a wide range of bioactive chemical compounds. They traditionally found application as flavour, fragrances and medicinal aroma. Today, the essential oils are sought-after for innumerable applications starting from markers for plant identifications to base for semi-synthesis of highly complex molecules. The extraction of highly delicate essential oils from plants remains a crucial step in all these applications. By using microwaves to mediate the extraction, it is possible to maintain mild conditions and effect superior extraction. However, apart from laboratory trials, essential oil extraction using microwave energy is largely an unexplored area. In the current work, an integrated procedure for microwave extraction followed by volatiles sampling and analysis from selected botanical raw materials (viz. black pepper, Piper nigrum and coriander Coriandrum sativum) was developed. There are two problems to overcome in the extraction from solid plant materials: that of releasing the essential oil from solid matrix and letting it diffuse out successfully in a manner that can be scaled-up to industrial volumes. Towards this end, an innovative volatiles extraction unit was conceived, designed and developed that used thin layer, for microwave exposure and rotational mixing, to mitigate the effects of thermal gradient and non-uniform exposure of bulk matter. The effect of varying the microwave field on the essential oils extracted was studied. The microwave field that coupled in the region of extraction was estimated from temperature rise measurement using the microwave power equation (with water as reference dielectric). The essential oil extracted under different microwave fields were compared using gas chromatography-mass spectrometry (GC-MS) and data analysis with SAS statistical software. The microwave field at the site of extraction was sensed by symmetrical placement of biomaterial sample and a reference, in a rotational extractor, such that they both couple the same field during tumbling motion. By measuring the temperature rise in the reference accurately, it is possible to estimate the microwave field present at that position. The rotational extractor has a second degree of freedom, in that it can slide along the axel taking discrete positions. Each position leads to a different microwave exposure of the sample. It is possible to measure the relative variation of microwave field using temperature rise data at each position. It was found that, at position labeled R4, located at 65.6 mm from the right extreme of the microwave cavity had the highest effective microwave field strength of value 92.7 V/m. The volatiles released from the biomaterials, black pepper and coriander, were sampled using solid phase micro extraction and analyzed using gas chromatography-mass spectrometry. The highest peaks representing beta-caryophyllene in black pepper and linalool in coriander were identified using mass spectrometric peak matching using NIST library.The extract (in terms of ion count) for each microwave parameter (such as field, water content level and solvent type) was plotted as a trend graph. The current experiment successfully tested the procedure for following the microwave process in the extraction of sensitive spice volatiles (from black pepper and coriander). With the microwave field measured at the region of extraction, it was possible to plot pepper extraction versus the microwave field to which the pepper sample was exposed. The extraction was represented in terms of cumulative value of ion counts obtained in GC-MS analysis. This unique procedure developed in the current research allows for the graphical comparison of the microwave extractions. It was found that black pepper has a better response to microwave extraction than coriander. The pepper extraction was found to increase proportionately with increase in microwave field strength. The extraction was also enhanced proportionately by the incremental addition of water content at constant microwave field.

Thesis (Ph. D.)(Chemistry)--University of Pretoria, 2003. / Includes bibliographical references.

Thesis (M.Tech.: Biotechnology)-Dept. of Biotechnology, Durban University of Technology, 2007 xv, 136 leaves / The chemical and biological properties of the essential oil from Cymbopogon validus were investigated. Hydro-distillation was used to extract the oil from C. validus, the flower-heads, leaves, culms and rhizomes. The percentage oil yields obtained from the plant organs varied from 0.05 to 1.23%, with the greatest concentration found in the flower-heads and rhizomes, 1.23 and 1.12% respectively. A sensory evaluation of the oil revealed that the essential oil was slightly murky, pale yellow in colour, had a strong turpentine-like smell and remained liquid at room temperature. The oxidative stability of C. validus oil was evaluated by determining its Rancimat induction period (negative), peroxide value (60.56 meq/kg), iodine value (84.55), percentage free fatty acids (0.19%) and percentage cholesterol (3.03%). These results indicated that the oil was highly susceptible to oxidation. Chromatographic profiles of the oils from C. validus, as well as the plant organs were generated using gas chromatography-mass spectroscopy (GC-MS). Predominant compounds present in the oil included alpha-Cubebene, Camphene, Geraniol, Limonene, Myrcene, Palmitic acid and Sabinene. C. validus essential oil was also investigated for its antimicrobial (disk diffusion), antioxidant (1, 1-Diphenyl-1-Picrylhydrazyl (DPPH) assay), anti-inflammatory (5-lipoxygenase assay), anti-mosquito properties (insecticidal, larvicidal and repellency assays) and toxicity profile (Brine shrimp and Ames assays). The oil showed poor antimicrobial activity and inhibited the growth of only Gram positive bacteria with a minimum inhibitory concentration (MIC) of 0.0625 (vol/vol) for Bacillus, Micrococcus and Staphylococcus species. The oil also exhibited excellent antioxidant activity, scavenging more than 80% of DPPH free radicals and possesses anti-inflammatory activity (IC50=190 ppm). C. validus oil showed good adulticidal activity (53.7% mortality) and excellent larvicidal (100% mortality) and repellent activity (100% repellency) against Anopheles arabiensis mosquitoes. At high concentrations, the oil was toxic to brine shrimp larvae. However, when diluted it was safe and the minimum inhibitory concentration was 0.0001(vol/vol). The absence of revertant colonies at all essential oil concentrations in the Ames test suggest that the oil is not mutagenic. These results lead the way for exploiting C. validus oil as a multi-functional agent that has antibacterial, anti-oxidant, anti-inflammatory, and anti-mosquito properties.

Darbo objektas: pašariniai kviečiai bei miežiai. Kviečių ir miežių mėginiai buvo gauti iš Prienų rajone esančių žemės ūkio įmonių. Mėginiai paimti atsitiktinės atrankos būdu iš saugyklų. Eterinių aliejų antigrybinis aktyvumas įvertintas difuzijos į agarą metodu. Darbo apimtis: 69 puslapių. Darbe pateiktos 9 lentelės, 16 paveikslų. Darbo tikslas: įvertinti eterinių aliejų antigrybines savybes mikromicetams, išskirtiems iš grūdų. Darbo uždaviniai: atrinkti komercinius eterinius aliejus pagal jų poveikį, sumažinant grūdų užsikrėtimą mikromicetais. Įvertinti atrinktų komercinių eterinių aliejų antigrybines savybes „lauko“ mikromicetams. Įvertinti atrinktų komercinių 100 proc. eterinių aliejų antigrybines savybes „sandėlių“ mikromicetams. Palyginti komercinių eterinių aliejų antigrybines savybes skirtingoms mikromicetų rūšims. Rezultatai ir aptarimas: Atrinkti 6 komerciniai eteriniai aliejai (raudonėlių, šalavijų, ciberžolių, čiobrelių, pipirmėčių ir levandų), pasižymintys antigrybinėmis savybėmis. Vertinant eterinių aliejų antigrybinį poveikį, parinktos keturios pagrindinės mikromicetų kultūros (Fusarium sp., Penicillium sp., Aspergillus sp., Alternaria sp.). Mikromicetų kultūras, veikiant skirtingu eterinių aliejų kiekiu (50; 25; 12,5; 6,25 μl), EO mažiausiai turėjo įtakos Aspergillus genties grybams. Fusarium genties grybai buvo jautriausi 50 ir 25 μl eterinių aliejų kiekiui. Mažinant eterinių aliejų kiekį (12,5 ir 6,25 μl) jautriausi antigrybiniam poveikiui buvo Penicillium... [toliau žr. visą tekstą] / Object of the thesis: feeding wheat and barleycorn. Samples of wheat and barleycorn were obtained from agricultural companies in Prienai district. Samples were taken from storage by random selection. Antifungal activity of essential oils was evaluated using method of diffusion to agar. Structure: 69 pages. There are 9 tables and 16 figures in the thesis. Objective of the thesis: to evaluate antifungal effect of essential oils on micromycetes isolated from grain. Tasks: to select commercial essential oils according to their effect, by decreasing infection of grain with micromycetes. To evaluate antifungal effect of selected commercial essential oils on micromycetes "outside". To evaluate antifungal effect of selected commercial 100% essential oils on micromycetes "in storage". To compare antifungal effect of commercial essential oils on different kinds of micromycetes. Results and discussion: 6 commercial essential oils (oregano, salvia, curcuma, thyme, peppermint and lavender) with antifungal properties were selected. When evaluating antifungal effect of essential oils, four main cultures of micromycetes were selected (Fusarium sp., Penicillium sp., Aspergillus sp., Alternaria sp). When applying different amounts of essential oils on cultures of micromycetes (50; 25; 12,5; 6,25 μl), the smallest effect was that of EO on genus Aspergillus fungi. Fungi of genus Fusarium were the most sensitive to the essential oil amounts of 50 and 25 μl. As the amount of essential oils was... [to full text]

Medicinal plants which have been widely used in folk medicine are known to contain important biologically active compounds. Most of today&rsquo / s synthetic drug raw materials are to be prepared by using plant originated compounds as the starting material. Hypericum Perforatum is one of the medicinal plants that grows in Europe, Western Asia and Northern Africa and is distinguished by its golden yellow flowers. The common name of the plant is St. John&rsquo / s wort. From the time of the ancient Greeks down through the middle Ages, the plant was considered to be imbued with magical powers and was used to ward off evil and protect against disease. As a practical folk-remedy, it has been used widely to heal wounds, remedy kidney troubles, and alleviate nervous disorders, even insanity. In the last thirty years, Hypericum perforatum has undergone extensive clinical and laboratory testing. The extract of the flower is a red liquid that contains many biologically active compounds such as: naphtodianthrones (hypericin, pseudohypericin), phloroglucinols (hyperforin, adhyperforin), flavonoids (quercetin, hyperoside, quercitrin, isoquercitrin, rutin, campferol, myricetin, amentofloavone), procyanidins (procyanidin, catechin, epicatechin polymers) , tannins (tannic acid), essential oils (terpenes, alcohols), amino acids (GABA, Cysteine, glutamine, leucine, lysine, ornithine, praline, threonine), phenyl propanes (caffeic acid, chlorogenic acid), xanthones (keilcorin, norathriol), organic acids peptides and polysaccharides (other water soluble compounds). These compounds have previously been isolated using HPLC method. The aim of this study is to isolate the main biologically active compound groups of Hypericum Perforatum and simply characterize the compounds with TLC, UV-VIS spectroscopy, NMR spectroscopy using standard compounds as references.

Thesis (MAppSc) -- AUT University, 2007. / Includes bibliographical references. Also held in print (x, 171 leaves : col. ill. ; 30 cm.) in City Campus Theses Collection (T 632.952 LIH)

Mémoire (B.Sc.)--Université du Québec à Chicoutimi, 1990. / Document électronique également accessible en format PDF. CaQCU

Thesis (M.S.)--Mississippi State University. Department of Plant and Soil Sciences. / Title from title screen. Includes bibliographical references.

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