Gerhard Buchbauer

Aromatherapy: Evidence for Sedative Effects of the Essential Oil of Lavender after Inhalation

The sedative properties of the essential oil of Lavender (Lavandula angustifolia Miller) and of its main constituents - linalool and linalyl acetate - were investigated in mice followed up in a series of experimental procedures. The significant decrease in the motility of female and male laboratory animals under standardized experimental conditions is found to be closely dependent on the exposure time to the drugs. Nevertheless after an injection of caffeine into mice a hyperactivity was observed which was reduced to nearly a normal motility only by inhalation of these fragrance drugs. In particular the correlation of the motility of the animals to linalool in serum is experimentally proven, thus furnishing evidence of the aromatherapeutical use of herbal pillows employed in folk medicine since ancient times in order to facilitate falling asleep or to minimize stressful situations of man.

Characterisation of various grape seed oils by volatile compounds, triacylglycerol composition, total phenols and antioxidant capacity.

Grape seed oil (Oleum vitis viniferae) representing a promising plant fat, mainly used for culinary and pharmaceutical purposes as well as for various technical applications, was subject of the present investigation. HS-SPME-GC-MS was applied to study volatile compounds in several seed oil samples from different grape oils. The triacylglycerol (TAG) composition of these oils was analyzed by MALDI-TOF-MS/MS. In addition the total phenol content and the antioxidant capacity (using TEAC) of these oils were determined. The headspace of virgin grape oils from white and red grapes was dominated by ethyl octanoate (up to 27.5% related to the total level of volatiles), ethylacetate (up to 25.0%), ethanol (up to 22.7%), acetic acid (up to 17.2%), ethyl hexanoate (up to 17.4%) and 3-methylbutanol (up to 11.0%). Triacylglycerol composition was found to be dominated by LLL (up to 41.8%), LLP (up to 24.3%), LLO (up to 16.3%) and LOO (up to 11.7%), followed by LOP (up to 9.3%) and LOS/OOO (up to 4.3%). Total phenol content ranged between 59μg/g and 115.5μg/g GAE. Antioxidant capacity (TEAC) was analyzed to range between 0.09μg/g and 1.16μg/g.

Combinatorial QSAR of Ambergris Fragrance Compounds

A combinatorial quantitative structure-activity relationships (Combi-QSAR) approach has been developed and applied to a data set of 98 ambergris fragrance compounds with complex stereochemistry. The Combi-QSAR approach explores all possible combinations of different independent descriptor collections and various individual correlation methods to obtain statistically significant models with high internal (for the training set) and external (for the test set) accuracy. Seven different descriptor collections were generated with commercially available MOE, CoMFA, CoMMA, Dragon, VolSurf, and MolconnZ programs; we also included chirality topological descriptors recently developed in our laboratory (Golbraikh, A.; Bonchev, D.; Tropsha, A. J. Chem. Inf. Comput. Sci. 2001, 41, 147-158). CoMMA descriptors were used in combination with MOE descriptors. MolconnZ descriptors were used in combination with chirality descriptors. Each descriptor collection was combined individually with four correlation methods, including k-nearest neighbors (kNN) classification, Support Vector Machines (SVM), decision trees, and binary QSAR, giving rise to 28 different types of QSAR models. Multiple diverse and representative training and test sets were generated by the divisions of the original data set in two. Each model with high values of leave-one-out cross-validated correct classification rate for the training set was subjected to extensive internal and external validation to avoid overfitting and achieve reliable predictive power. Two validation techniques were employed, i.e., the randomization of the target property (in this case, odor intensity) also known as the Y-randomization test and the assessment of external prediction accuracy using test sets. We demonstrate that not every combination of the data modeling technique and the descriptor collection yields a validated and predictive QSAR model. kNN classification in combination with CoMFA descriptors was found to be the best QSAR approach overall since predictive models with correct classification rates for both training and test sets of 0.7 and higher were obtained for all divisions of the ambergris data set into the training and test sets. Many predictive QSAR models were also found using a combination of kNN classification method with other collections of descriptors. The combinatorial QSAR affords automation, computational efficiency, and higher probability of identifying significant QSAR models for experimental data sets than the traditional approaches that rely on a single QSAR method.

Antimicrobial study of essential oils of Ocimum gratissimum leaves and Zanthoxylum xanthoxyloides fruits from Cameroon.

An investigation of antimicrobial activities of essential oils of fresh leaves of Ocimum gratissimum and the essential oil of the dried fruits of Zanthoxylum xanthoxyloides was carried out. The essential oils showed extensive inhibition zones and are, therefore, effective antimicrobial systems.

Antimicrobial activity of Pelargonium essential oils added to a quiche‐filling as a model food system

Eight essential oils obtained by steam distillation from the scented leaves of Pelargonium species and cultivars were added at 250, 500 and 1000 ppm to a quiche filling, inoculated with either Saccharomyces ludwigii or Zygosaccharomyces bailii (at 108 cfu g−1), Salmonella enteriditis or Listeria innocua (at 109 cfu g_1). The quiche fillings were then kept at 25 °C for 24 h and the residual number of micro‐organisms determined using the pour plate technique. There was an effective antimicrobial activity by the Pelargonium essential oils at 250 ppm, comparable with that of commercial thyme oil, an excellent antimicrobial agent, against Saccharomyces ludwigii and Zygosaccharomyces bailii, and a lesser inhibition compared with commercial thyme against Salm. enteriditis. There was a greater diversity of activity against L. innocua, which was in some cases more effective than commercial thyme oil. At 500 ppm, there was a greatly increased inhibition of microbial growth using the Pelargonium essential oils, which was comparable with that of commercial thyme, clove, geranium and coriander oils. As there is no evidence for the toxicity of any of these novel Pelargonium oils, and their odour does not make the delicately flavoured quiche filling unpalatable, there is a strong potential for their use in food processing.

Chemical composition of essential oils of Lantana camara leaves and flowers from Cameroon and Madagascar

The essential oils of leaves and flowers of Lantana camara (Verbenaceae) from Cameroon and Madagascar were analysed by GC–FID and GC–MS. The oils are characterized by a high percentage of sesquiterpenes. The major components in the oils from Cameroon are ar-curcumene (25%), β-caryophyllene (13%) and caryophyllene epoxide (7%), while the main components of the oil from Madagascar are davanone (15%) and β-caryophyllene (12%). The monoterpenes percentages are lower in the two essential oils and are represented by sabinene (1–9%), α-pinene (2–4%), 1,8-cineole (1–3%) and linalool (1–3%). A comparison with the composition of various essential oils of L. camara with different origin will also be given. Copyright

Comparative antibacterial effects of novel Pelargonium essential oils and solvent extracts

The scented leaves of a number of Pelargonium (Geraniaceae) species and cultivars were extracted using steam distillation, petroleum spirit and methanol. The extracts were assessed for their antibacterial activity in vitro against Staphylococcus aureus, Proteus vulgaris, Bacillus cereus and Staph. epidermidis. The results indicated substantial antibacterial activity and suggested that Pelargonium essential oils could be used as novel antibacterial agents. The methanolic and petroleum spirit extracts were more potent antibacterial agents than the steam-distilled volatile samples. The results suggest that Pelargonium essential oils and solvent extracts could be used as novel food or cosmetic antimicrobial agents.

Correlation of Antimicrobial Activities of Various Essential Oils and Their Main Aromatic Volatile Constituents

Abstract The pure aromatic volatiles p-cymene, carvacrol, eugenol and thymol as well as commercial essential oils of Cinnamomum zeylanicum, Origanum vulgare, Pimenta dioica, Pimenta racemosa, Satureja hortensis, Syzygium aromaticum, Thymus vulgaris and Trachyspermum ammi were investigated concerning antimicrobial activities. Therefore, these samples and, as reference substances, synthetic antibiotics and the natural antimicrobial components carveol, m-, o- and p-cresol were tested against strains of two Gram-positive and five Gram-negative bacteria and the yeast Candida albicans using agar dilution and agar diffusion methods. The analysis of the chemical composition of the essential oils by means of GC and GC/MS focusing on aromatic volatiles produced the following results: C. zeylanicum: eugenol (74.9%); O. vulgare: carvacrol (66.1%) and p-cymene (9.2%); P. dioica: eugenol (76.0%); P. racemosa: eugenol (45.6%); S. hortensis: carvacrol (41.5%), p-cymene (10.7%) and thymol (8.7%); S. aromaticum: eugenol (76.8%); T. vulgaris: thymol (43.4%), p-cymene (23.5%) and carvacrol (4.1%); T. ammi: thymol (43.7%) and p-cymene (17.7%). All investigated aromatic volatiles and essential oils exhibited strong effects against the yeast Candida albicans and medium to strong antimicrobial activity against the Gram-positive bacteria Staphylococcus aureus and Enterococcus faecalis and the Gram-negative bacteria Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris, and Salmonella sp., whereas weaker effects were observed against Pseudomonas aeruginosa.

Transdermal absorption of (-)-linalool induces autonomic deactivation but has no impact on ratings of well-being in humans.

Essential lavender oil has a long tradition as a mild sedative in herbal medicine. Relaxing effects after inhalation have also been demonstrated for one of its main constituents, (−)-linalool. The aim of the present investigation was to determine the effects of this monoterpenoid alcohol on human physiological parameters (blood oxygen saturation, breathing rate, eye-blink rate, pulse rate, skin conductance, skin temperature, surface electromyogram as well as systolic and diastolic blood pressure) and assessments of subjective well-being. (−)-Linalool was applied to 14 healthy subjects by percutaneous administration. Inhalation of the fragrance was prevented by means of breathing masks. (−)-Linalool induced deactivation with respect to physiology, that is, a decrease of systolic blood pressure and a smaller decrease of skin temperature, compared to a corresponding control group receiving a placebo, but had no effects on subjective evaluation of well-being.

Composition and Antioxidant Activities of the Essential Oil of Cinnamon (Cinnamomum zeylanicum Blume) Leaves from Sri Lanka

Abstract The composition of the volatiles from leaves of Cinnamomum zeylanicum Blume from Sri Lanka was studied by GC-FID and GC-MS. The basic component of the oil was found to be eugenol (74.9%), followed by β-caryophyllene (4.1%), benzyl benzoate (3.0%), linalool (2.5%), eugenyl acetate (2.1%) and cinnamyl acetate (1.8%). The essential leaf oil from cinnamon demonstrated scavenger activity against the DPPH radical at concentrations which are lower than the concentrations of eugenol, butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA). This essential cinnamon oil showed also a significant inhibitory effect on hydroxyl radicals and acted as an iron chelator. Cinnamon leaf oil efficiently inhibited the formation of conjugated dienes and the generation of secondary products from lipid peroxidation at a concentration equivalent to that of the standard BHT.