Petras Rimantas Venskutonis

Natural and synthetic antioxidants: An updated overview

Abstract The current understanding of the complex role of ROS in the organism and pathological sequelae of oxidative stress points to the necessity of comprehensive studies of antioxidant reactivities and interactions with cellular constituents. Studies of antioxidants performed within the COST B-35 action has concerned the search for new natural antioxidants, synthesis of new antioxidant compounds and evaluation and elucidation of mechanisms of action of both natural and synthetic antioxidants. Representative studies presented in the review concern antioxidant properties of various kinds of tea, the search for new antioxidants of herbal origin, modification of tocopherols and their use in combination with selenium and properties of two promising groups of synthetic antioxidants: derivatives of stobadine and derivatives of 1,4-dihydropyridine.

Nutritional Components of Amaranth Seeds and Vegetables: A Review on Composition, Properties, and Uses

 A few decades ago Amaranthus was rediscovered as a most promising plant genus that may provide high-quality protein, unsaturated oil, and various other valuable constituents. Since then research has focused on various Amaranthus spp. and has been rapidly expanding, and a large number of reports have been published. Several review articles focusing on different aspects, such as botanical, agrotechnological, compositional, biological, chemical, and technological properties, as well as applications and health effects, have also been published since then. This comprehensive review is focused on amaranth composition, antioxidant properties, applications, and processing. The composition includes macrocomponets (lipids, proteins, carbohydrates, and dietary fiber) and other important constituents, such as squalene, tocopherols, phenolic compounds, phytates, and vitamins. These aspects of amaranth studies have not been comprehensively reviewed for a long time.

Antioxidative activity of sage (Salvia officinalis L.), savory (Satureja hortensis L.) and borage (Borago officinalis L.) extracts in rapeseed oil

The antioxidant activity (AA) of acetone oleoresins (AcO) and deodorised acetone extracts (DAE) of sage (Salvia officinalis L.), savory (Satureja hortensis L.) and borage (Borago officinalis L.) were tested in refined, bleached and deodorised rapeseed oil applying the Schaal Oven Test and weight gain methods at 80 °C and the Rancimat method at 120 °C. The additives (0.1 wt-%) of plant extracts stabilised rapeseed oil efficiently against its autoxidation; their effect was higher than that of the synthetic antioxidant butylated hydroxytoluene (0.02%). AcO and DAE obtained from the same herbal material extracted a different AA. The activity of sage and borage DAE was lower than that of AcO obtained from the same herb, whereas the AA of savory DAE was higher than that of savory AcO. The effect of the extracts on the oil oxidation rate measured by the Rancimat method was less significant. In that case higher concentrations (0.5 wt-%) of sage and savory AcO were needed to achieve a more distinct oil stabilisation.

Chemical composition of the essential oil of different varieties of thyme (Thymus pulegioides) growing wild in Lithuania

Abstract Twenty-five samples of Thymus pulegioides L. representing two varieties of subsp. silvestris and four varieties of subsp. pulegioides were collected from 11 localities in Lithuania and the composition of their essential oil was analysed by capillary gas chromatography (GC) and mass spectrometry (MS). Five chemotypes have been defined for the species using hierarchical cluster analysis: (1) linalool (L)—one sample; (2) geranial/geraniol/neral (G/G/N)—11 samples; (3) thymol (T)—two samples; (4) carvacrol/γ-terpinene/ p -cymene (C/γT/pC)—seven samples; (5) thymol/carvacrol/ p -cymene/γ-terpinene (T/C/pC/γT)—four samples. It was concluded that there is no clear relation in essential oil composition between the studied taxa and the chemical types detected. Four different chemotypes were defined within the subsp. s ilvestris var. conglomeratus , three chemotypes within the subsp. pulegioides var. pulegioides and var. ovatus . The G/G/N-chemotype is the most frequently found, followed by the phenolic types, the linalool chemotype being recorded only once. Both infra-specific and intra-population chemical polymorphisms were recorded.

Composition of Essential Oil of Sweet Flag (Acorus calamus L.) Leaves at Different Growing Phases

Abstract The essential oil composition of Acorus calamus (sweet flag) leaves collected in Lithuania at different growing phases was examined by GC and GC/MS. Rhizome oils of A. calamus, having been more thoroughly investigated, were used for comparison purposes. The content of the oil in dried sweet flag rhizomes was 1.20± 0.12% and in the leaves, depending on the vegetation phase, was from 0.56–1.01%. Ninety-one constituents were positively or tentatively identified in the oils—66 in the leaves and 55 in the rhizomes. Possible formation of calacorene hydrates is suggested for the first time on the basis of mass spectral data. δ-Asarone [(Z)-asarone] was the major constituent in the leaves (27.4–45.5%), whereas acorenone was dominant in the rhizomes (20.86%) followed by isocalamendiol (12.75%). A higher content of some aliphatic and oxygenated monoterpenes was found in oils of the leaves at their earliest growth phase (May), while the β-asarone content was at its lowest level.

Antioxidant activity of horehound (Marrubium vulgare L.) grown in Lithuania

Acetone extracts (AE), deodorised acetone extracts (DAE), and deodorised water extracts (DWE) from leaves of horehound (Marrubium vulgare L. ) were tested for their antioxidant activity in rapeseed ( Brassica napus L.) oil at 80 °C. Well investigated antioxidants containing extracts (AE and DAE) of sage (Salvia officinalis L.) were used for comparison purposes. The effect of the extracts on the edible oil stability was assessed by measuring weight gain, peroxide value, and the UV absorption. The antioxidant activity of AE and DAE of horehound were comparable to the antioxidant activity of AE and DAE of sage. For both plants AE was shown to have better antioxidant properties than DAE. The volatile components of horehound were hydrodistilled and analysed by GC and GC/MS. Totally, 47 components were identified in the essential oil (EO), the main ones being (Z)- β-farnesene, βcaryophyllene, (E)-hex-2-enal, α-humulene, and germacrene D. Thirtynine constituents are reported in M. vulgare for the first time.

A Chemotype of Mentha longifolia L. from Lithuania Rich in Piperitenone Oxide

ABSTRACT The volatile constituents of Mentha longifolia L. were isolated by hydrodistillation and simultaneous distillation-extraction method in the Likens-Nickerson apparatus and analyzed by GC and GC/MS. Seventy compounds were identified, 62 positively and 8 tentatively. The major constituents were piperitenone oxide (44.2% and 57.2%), 1,8-cineole (15.14% and 8.44%), myrcene (10.02% and 6.27%), limonene (4.28% and 3.45%), β-caryophyllene (1.72% and 3.34%) and germacrene D (1.51% and 4.11%).

Effect of fast CO2 pressure changes on the yield of lovage (Levisticum officinale Koch.) and celery (Apium graveolens L.) extracts

The effect of pressure alterations on the yield of CO2, extracts from different anatomical parts of lovage (Levisticum officinale Koch.) and celery (Apium graveolens L.) was studied. It was found that by applying frequent pressure changes in the extraction vessel it is possible to increase the rate of the isolation of CO2 soluble materials from lovage seeds and leaves, lovage and celery roots. However, after passing a sufficient amount of the supercritical solvent, the yields were similar both for constant and pulsing extraction pressures. The composition of the extracts was analyzed by gas chromatography and mass spectrometry and it was found that the phthalides were very important constituents in the extracts from all the anatomical parts of lovage, while linoleic acid was the most abundant component in the celery root extracts

Antioxidant properties and essential oil composition of Calamintha grandiflora L.

Essential oil was isolated from the leaves of Calamintha grandiflora L. by hydrodistillation and analysed by gas chromatography-mass spectrometry (GC-MS). The most abundant compounds in C. grandiflora essential oil were isomenthone, neo-isomenthol, pulegone and isomenthol, constituting 34.07%, 7.65%, 19.83% and 19.54%, respectively. The residues obtained after hydrodistillation were separated into the solid and liquid fractions, the former one was extracted with acetone, methanol and ethanol, while the latter one was sprayed or freeze dried. Antioxidant potential of extracts was evaluated by DPPH() (batch and HPLC-on-line) and ABTS(+) radical scavenging, ferric ion reduction (FRAP) assays and by the effect on oil peroxidation in Oxipres apparatus. The content of total phenolic compounds, flavonoids and flavonols was determined spectrophotometrically. Rosmarinic and salvianolic C acids were identified as the main antioxidants in C. grandiflora.

Antimicrobial activity of commercial samples of thyme and marjoram oils

Abstract Commercial samples of thyme and marjoram oils were analyzed by capillary GC and coupled GC/MS. The antimicrobial activity of each oil was assessed against 10 different bacteria and eight strains of yeasts. p-Cymene (25.2%), thymol (31.4%) and carvacrol (3.8%) were important compounds in the oil of thyme, while limonene (17.3%), linalool (15.5%), terpinen-4-ol (7.3%), α-terpineol (13.0%) and linalyl acetate (14.1%) were major constituents in marjoram oil. Thyme oil possessed remarkable antimicrobial activity against the tested microorganisms, while marjoram oil demonstrated a lower antimicrobial activity. The antimicrobial activity of oils was higher against yeasts than bacteria.