Chemical composition and comparative analysis of lavender essential oil samples from Bulgaria in relation to the pharmacological effects

Lavender essential oil is economically important and widely used in aromatherapy perfumery, food industry and pharmacy. Bulgaria is a global leader in lavender cultivation overtaking countries such as France, UK, China, India, and Spain during the last few years. The aim of this research is: 1) to characterize a lavender essential oil sample obtained from agricultural plantation near Pomorie, Bulgaria; 2) to perform descriptive statistical test based on a data set of 13 samples available in 4 publications, 3) to compare the varieties regarding the quantity of the most important components such as linalool and linalyl acetate 4) to summarize the pharmacological effects of the main components. As a result of GS/MS analysis of the essential oil sample obtained from agricultural plantation near Pomorie, we identified 44 compounds. The major constituents were linalyl acetate (27.5%) linalool (24.1%), E-β-ocimene (7.0%), terpinen-4-ol (5.1%) caryophyllene (4.5%), carvacrol (4.4%), lavandulyl acetate (3.5%), Z-β-farnesene (3.3%), and -Z-β-ocimene (3.2%). Linalool and linalyl acetate are the main ingredients based on which the quality of the essential oil is evaluated. In the studied samples they fluctuated between varieties depending on the year of extraction and the locations of origin in Bulgaria. Some varieties were characterized by a more stable ratio of linalool – linalyl acetate, compared to others. The main other components of our sample as well as the other examined Bulgarian samples fit the standards according to the requirements of ISO (2002) and the of European Pharmacopoeia (10th edn., Council of Europe 2020) with few exceptions. Lavender oil has numerous pharmacological applications based on its anxiolytic, sedative, antioxidant, anti-inflammatory, antitumor and antimicrobial activities. Although linalool and linalyl acetate largely contribute to these effects, the overall efficacy of lavender oil is proven to be due synergistic relationships between the components

Synthesis of Some Phenylpropanoid Monoglycerides via the Mitsunobu Protocol

Natural monoglycerides of cinnamic, ferulic and p-coumaric acids were synthesized in good to high overall yields from isopropylidene glycerol via the Mitsunobu reaction and further deprotection of the corresponding acetonides with Amberlyst 15. The method avoids the need of protection of the phenolic hydroxyls. During the Mitsunobu esterifications a strong influence of the acid strength on the efficacy and outcome of the reaction was observed

Original scientific paper

Seasonal variations in the leaf surface composition o

Lavender essential oils–hidden relationships between the samples of origin

Lavender essential oil is an economically important ingredient in perfumery, the food industry, and pharmacy. There is notable diversity in the composition of lavender essential oils. The reasons are the high genetic diversity of lavender cultivars and the variety of ecological specifics in the regions of cultivation. The aim of this research is to check which lavender essential oil variety is best regarding the content of the most important components through comparative statistical tests. We created a data set of 88 lavender essential oil samples from 16 countries. The multivariate statistics (hierarchical and non-hierarchical clustering) and factor analysis reveal hidden relationships between the objects of the study (samples) or between the variables characterizing the objects (chemical descriptors–16 components). The results are discussed in detail. All samples from Bulgaria, together with a few of the Italian, French, Greek, Indian, and Chinese samples, fall into one cluster with the standard maximums. Graphical abstract

Antibacterial acticivity of extracts from Potentilla reptans L.

Potentilla reptans is widely used in traditional medicine as an astringent, for treating diarrhoea, haemorrhoids and for bleeding gums. A recent ethnobotanical study has reported on the anti-mastitis effects of the aerial parts of P. reptans decoction. The aim of the present study is to evaluate the antibacterial potential of extracts and fractions, obtained from aerial parts of P. reptans against three strains of Staphylococcus aureus. The observed MICs were within the range of 0.325 – 2.5 mg/ml. Studied extracts and their fractions exerted mostly bacteriostatic effect, with the n-hexane fraction of hydroethanolic extract being the most active (MIC 0.313 mg/ml against S. aureus ATCC 6538 P). However, further investigations are necessary to reveal the precise mode of action of P. reptans against mastitis

Antibacterial acticivity of extracts from Potentilla reptans L.

Potentilla reptans is widely used in traditional medicine as an astringent, for treating diarrhoea, haemorrhoids and for bleeding gums. A recent ethnobotanical study has reported on the anti-mastitis effects of the aerial parts of P. reptans decoction. The aim of the present study is to evaluate the antibacterial potential of extracts and fractions, obtained from aerial parts of P. reptans against three strains of Staphylococcus aureus. The observed MICs were within the range of 0.325 – 2.5 mg/ml. Studied extracts and their fractions exerted mostly bacteriostatic effect, with the n-hexane fraction of hydroethanolic extract being the most active (MIC 0.313 mg/ml against S. aureus ATCC 6538 P). However, further investigations are necessary to reveal the precise mode of action of P. reptans against mastitis

Synthesis and Antioxidant Activity of Polyhydroxylated trans-Restricted 2-Arylcinnamic Acids

A series of sixteen polyhydroxylated trans-restricted 2-arylcinnamic acid analogues 3a–p were synthesized through a one-pot reaction between homophthalic anhydrides and various aromatic aldehydes, followed by treatment with BBr3. The structure of the newly synthesized compounds was confirmed by spectroscopic methods and the configuration around the double bond was unequivocally estimated by means of gated decoupling 13C-NMR spectra. It was shown that the trans-cinnamic acid fragment incorporated into the target compounds’ structure ensures the cis-configuration of the stilbene backbone and prevents further isomerization along the carbon–carbon double bond. The antioxidant activity of compounds 3a–p was measured against 1,1-diphenyl-2-picrylhydrazyl (DPPH●), hydroxyl (OH●) and superoxide (O2●▬) radicals. The results obtained showed that the tested compounds possess higher activities than natural antioxidants such as protocatechuic acid, caffeic acid and gallic acid. Moreover, it was shown that a combination of two different and independently acting fragments of well-known pharmacological profiles into one covalently bonded hybrid molecule evoke a synergistic effect resulting in higher than expected activity. To rationalize the apparent antioxidant activity and to establish the mechanism of action, a SAR analysis and DFT quantum chemical computations were also performed

Evaluation of the radical scavenging activity of a series of synthetic hydroxychalcones towards the DPPH radical

Sixteen hydroxychalcones were synthesized in sufficient purity by the Claisen–Schmidt condensation between appropriate acetophenones and aromatic aldehydes. All the compounds were evaluated for their ability to scavenge the stable free 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. Important structure–activity relationships were observed that strongly contribute to the knowledge for the design of DPPH radical scavenging chalcones. Relevant theoretical parameters were computed in an attempt to understand and explain the obtained experimental results