Chemical composition and antioxidant activities of Myrtus communis L. berries extracts

Myrtle (Myrtus communis L.) berries extracts were prepared with solvents at different polarity (water, ethanol, and ethyl acetate) and analysed using different in vitro tests in order to evaluate their antioxidant properties. Antiradical and total antioxidant activities were measured with DPPH and FRAP tests, respectively. Their ability to protect biological molecules was assessed using the cholesterol and LDL oxidation assays. In addition, phenolic compounds and unsaturated fatty acids composition was analysed by HPLC–DAD and HPLC–MS/MS. Ethanol and water extracts showed the highest amount of extracted compounds, but the highest antiradical and antioxidant activities were found in ethanol and ethyl acetate extracts. These extracts were also the ones with the highest content of phenolic compounds. In addition, our results showed a highly significant correlation between the amount of total phenols and antiradical (R² = 0.9993) or antioxidant activities (R² = 0.9985) in these extracts. HPLC–DAD and HPLC–MS analyses showed significant quantitative and qualitative differences among these three extracts. The ethyl acetate extract had the highest protective effect in assays of thermal (140 °C) cholesterol degradation and Cu²⁺-mediated LDL oxidation, inhibiting the reduction of polyunsaturated fatty acids and cholesterol, and the increase of their oxidative products. These results suggest that because of these properties, myrtle berries could be used in dietary supplements preparations or as food additives.     

Myrtle hydroalcoholic extracts obtained from different selections of Myrtus communis L.

Hydroalcoholic extracts obtained from myrtle berries of five different selections were studied to obtain unique clones. During the typical 40 day maceration period, dry matter, pH, colour, and anthocyanins, were analyzed. Variability among myrtle selections was observed both in fresh berries (yield berries/plant, weight of the berries, number and weight of seeds per berry) and in the hydroalcoholic extract physical–chemical characteristics (dry matter, colour intensity, tint and anthocyanins). Reversed-phase high performance liquid chromatography (RP-HPLC) analysis with photodiode array detection (PDA) was used for anthocyanins characterization in myrtle hydroalcoholic extracts. Anthocyanin qualitative composition was the same in all selections, but varied strongly in its total amount. D was the selection with the characteristics most suitable for industrial use.     

Essential oil composition of Pistacia lentiscus L. and Myrtus communis L.: Evaluation of antioxidant capacity of methanolic extracts

The seasonal variation of the essential oil composition, the antioxidant activity (DPPH, FRAP assays) and the total phenolic content (Folin-Ciocalteu assay) of two aromatic wild plants, Pistacia lentiscus L. (Anacardiaceae) and Myrtus communis L. (Myrtaceae), grown in Zakynthos, a Greek island, was investigated. The essential oil was obtained by hydrodistillation and subsequently analysed by GC–MS.     

Activity guided isolation of antioxidants from the leaves of Ricinus communis L.

An activity-guided isolation and purification process was used to identify the DPPH (l,l-diphenyl-2-picrylhydrazyl) free radical scavenging components of the food plant (Ricinus communis L.) of Eri silkworm. Dry leaves of R. communis L. were extracted with different solvents and tested for their antioxidant activity against DPPH^•. The MeOH:water (8:2) extract showed strong DPPH radical-scavenging activity, and was subjected to column chromatography over silica gel. Gallic acid, quercetin, gentisic acid, rutin, epicatechin and ellagic acid were isolated as active components and characterised by different spectroscopic techniques.     

Characterisation of volatiles and polyphenols for quality assessment of alcoholic beverages prepared from Corsican Myrtus communis berries

In the present work, the essential oil compositions of Myrtus communis berries from ten Corsican localities were studied and no chemical variability was observed. HS–SPME, GC and GC/MS analysis were carried out for the characterisation of volatile fractions of M. communis berries and two derived commercial alcoholic beverages (liqueur and eau-de-vie). Quantitative variations due to the distillation process were observed between the two beverages. The volatile compositions of Corsican myrtle alcoholic products were characterised by high amounts of monoterpene hydrocarbons and oxygenated monoterpenes with α-pinene and 1,8-cineole as major components. The polyphenolic compositions of the berry extract and the liqueur were also established using HPLC–DAD and LC–MS–MS; high concentrations of flavonol glycosides, flavonols and flavanols were reported.     

Comparative chemical composition,antioxidant and hypoglycaemic activities of Juniperus oxycedrus ssp. oxycedrus L. berry and wood oils from Lebanon

Juniper (Juniperus oxycedrus) is used in European cuisine for its distinguishing flavour. J. oxycedrus ssp. oxycedrus berry and wood essential oils were tentatively identified by GC and GC/MS. Fifty compounds were identified in the berry oil and 23 compounds were identified in the wood oil. The J. oxycedrus ssp. oxycedrus berry oil was characterised by high contents of α-pinene (27.4%) and β-myrcene (18.9%). Other important compounds were α-phellandrene (7.1%), limonene (6.7%), epi-bicyclosesquiphellandrene (2.3%) and δ-cadinene (2.2%) while, in the wood oil, δ-cadinene (14.5%) is a major main component, together with cis-thujopsene (9.2%) and α-muurolene (4.9%). In vitro evaluation of antioxidant activity by the DPPH method showed a significant activity for both oils with IC₅₀ values of 1.45 μl/ml for wood and 7.42 μl/ml for berries. Hypoglycaemic activity was investigated through the inhibition of α-amylase. The results revealed that oil obtained by hydrodistillation from J. oxycedrus ssp. oxycedrus wood exhibits an interesting activity with IC₅₀ of 3.49 μl/ml.     

Application of Central Composite Design to evaluate the antilisterial activity of hydro-alcohol berry extract of Myrtus communis L.

The antimicrobial activity of the hydro-alcohol extract of Myrtus communis L. (ME) berries was investigated against six Listeria monocytogenes strains (2 type strains and 4 isolates). Sub-lethal ME concentrations reduced L. monocytogenes counts by at least 2 log cycles. A Central Composite Design was used to investigate the combined effects of sub-lethal concentrations of ME (0.039–0.195 mL/100 mL), NaCl (0–2.0 g/100 mL) and pH (5.0–7.0) on strains growth. ME affected growth parameters, generally extending lag phase length and reducing maximum growth, sometimes with interactive effects with pH. The highest ME concentrations (0.117–0.195 mL/100 mL) combined with the lowest pH values (5.0–6.0) strongly reduced or even inhibited strains growth.     

Extraction and identification of anthocyanins from Smilax aspera L. berries

Anthocyanins, present in the berries of Smilax aspera L., a creeping shrub typical of the Mediterranean region, were extracted and identified for the first time. The pigments were extracted from the skin of the berries with of 0.1% HCl in methanol solution, purified on a C-18 solid-phase cartridge and characterized by means of HPLC-DAD-MS analysis. From spectral analysis before and after acid and alkaline hydrolysis, it was noted that pelargonidin 3-O-rutinoside represented about 83% of the total anthocyanin content in the skin of Smilax aspera berries. A low quantity of cyanidin 3-O-rutinoside (13%) was also found. The attractive colour and the great abundance of the plant in the south of Italy make Smilax aspera berries a new and very good source of natural pigments.     

Headspace volatiles from frozen berries of sea buckthorn (Hippophaë rhamnoides L.) varieties

The volatile compounds of frozen berries of seven sea buckthorn (Hippophaë rhamnoides L.) varieties of two growing seasons were isolated with solid phase microextraction (SPME), and analyzed with gas chromatography mass spectrometry. A total of 45 volatiles were identified from the headspace. The most numerous compounds found were esters of short chain normal or branched alcohols and acids. Ethyl 2-methylbutanoate, ethyl 3-methylbutanoate, ethyl hexanoate, 3-methylbutyl 3-methylbutanoate, ethyl octanoate and 3-methylbutyl hexanoate were the most abundant compounds identified, and they contribute over 70% of the total peak area found in samples. Principal component analysis (PCA) showed differences between the years studied as well as between varieties. Raisa of ssp. rhamnoides origin had the highest variance in the volatile profile compared to the varieties of ssp. mongolica origin.     

Application of response surface methodology and central composite design for the optimisation of supercritical fluid extraction of essential oils from Myrtus communis L. leaves

Essential oils of Myrtus communis L. leaves were obtained using supercritical fluid extraction (SFE) and hydrodistillation methods. The experimental parameters of SFE such as pressure, temperature, modifier volume, static and dynamic extraction time were optimised using a central composite design after a 2ⁿ⁻¹ fractional factorial design. The chemical compositions of the SFE extract were identified by GC–MS and determined by GC–FID. The major components of essential oils obtained by hydrodistillation were α-pinene (31.8%), 1,8-cineole (24.6%), limonene (14.8%), linalool (8.3%) and α-terpinolene (4.8%). However, by using the supercritical carbon dioxide in optimum conditions, only three components represented more than 85% of the extract. Therefore, by using the proper SFE conditions, the supercritical extraction is more selective than the conventional hydrodistillation methods. The oil yields based on the hydrodistillation was 0.47% (v/w). Extraction yields based on the SFE varied in the range of 0.5–6.3% (w/w) under different conditions.     

Optimization of HS-SPME conditions for quantification of 2-acetyl-1-pyrroline and study of other volatiles in Pandanus amaryllifolius Roxb.

HS-SPME coupled with GC–FID was applied for the quantification of 2-acetyl-1-pyrroline (2AP) in Pandanus amaryllifolius, the best available natural source of (2AP). Conditions for qualitative and quantitative analysis of aroma volatiles with special reference to 2AP from P. amaryllifolius have been optimized using HS-SPME/GC–FID. About 10 mg powdered leaf material at 80 °C temperature for 35 min was found to be the most effective combination for maximum release of 2AP. Volatile analyses led to the identification of 31 compounds, of which 21 are reported for the first time in P. amaryllifolius. 2AP contents and other volatiles were found to vary in small and large growth forms.     

Antioxidants and antiradicals in almond hull and shell (Amygdalus communis L.) as a function of genotype

To compare the antioxidant and antiradical activity of Amygdalus communis L. hulls and shells phenolic extracts in different genotypes, 18 A. communis L. genotypes were selected from those in Qooshchi, Qalgachi, Qovarchin Qale, Najaf Abad, Jamal Abad, Kahriz, Sfahlan of West and East Azerbayjan provinces of Iran in 2007. The fruits of these almonds were collected, their hulls and shells dried, ground and then methanolic extracts prepared from these hulls and shells. Total phenolic content was determined using the Folin–Ciocalteu (F–C) method. The extracts’ reducing power and scavenging capacity for radical nitrite, hydrogen peroxide and superoxide were evaluated. Significant differences were found in phenolic content of hulls and shells among various genotypes, radical scavenging capacity percentage varied significantly among genotypes and their hulls and shells. S₃-7 genotype with the highest phenolic content and antioxidant activity in its hulls represents a valuable genotype for procuring antioxidant phenolic compounds.     

Comparative analysis of clary sage (S. sclarea L.) oil volatiles by GC–FTIR and GC–MS

The comparative analysis of volatiles in essential oil by gas chromatography–Fourier transform infrared spectrometry (GC–FTIR) and gas chromatography–mass spectrometry (GC–MS) are investigated using a DB-wax capillary column. This technique is applied to allelochemicals present in volatiles. The identification analysis of volatile components in four kinds of clary sage (Salvia sclarea L.) oil is described. The GC–FTIR information obtained is complementary to the information obtained from GC–MS. With the IR subtractive spectrum technique, the GC overlap peaks can be resolved without further separate step on the other column of different polarity. Combined with GC–FTIR, GC–MS techniques, and linear retention indices (RI) of the volatile compounds, the reliability of qualitative analysis is greatly enhanced.     

Variations in essential oil and fatty acid composition during Myrtus communis var. italica fruit maturation

The essential oil and fatty acid composition of Myrtus communis var. italica fruit during its ripening was determined. The effect of the harvesting time on some physical properties of Myrtus fruits, fruit weight and moisture content, were significant. The increase of fruit weight (from 2.54 to 8.79 g% fruits) during ripeness was correlated positively with that of moisture content (from 28% to 72%). Fruit essential oil yields varied from 0.003% to 0.01% and showed a remarkable increase at 60 days after flowering to reach a maximum of 0.11%. Forty-seven volatile compounds were identified in fruit essential oils; 1,8-cineole (7.31–40.99%), geranyl acetate (1.83–20.54%), linalool (0.74–18.92%) and α-pinene (1.24–12.64%) were the main monoterpene compounds. Total fatty acid contents varied from 0.81% to 3.10% during fruit maturation and the predominant fatty acids were linoleic (12.21–71.34%), palmitic (13.58–37.07%) and oleic (6.49–21.89%) acids. The linoleic acid proportions correlated inversely with palmitic and oleic acids during all the stages of ripening.     

Juniperus sibirica Burgsdorf. as a novel source of antioxidant and anti-inflammatory agents

In order to examine antioxidant properties of methanol extracts of cones and needles of the unexplored Juniperus sibirica Burgsdorf. (Cupressaceae) species, various assays which measure free radical scavenging ability were carried out: DPPH, hydroxyl, superoxide anion and nitric oxide radical scavenger capacity test and reducing power (FRAP) assay. In all of the tests the extracts showed a potent antioxidant effect compared with BHT, a well-known synthetic antioxidant. In addition, the anti-inflammatory activity considering inhibitory potency toward COX-1 and 12-LOX was observed. Both extracts showed markedly anti-inflammatory activity, with needles having somewhat higher potency concerning both assays, reaching IC₅₀ at 1.29 mg/mL towards COX-1 and IC₅₀ at 1.34 mg/mL towards 12-LOX. Besides, in the extracts examined the total phenolic and flavonoid amounts were also determined, together with presence and content of the selected flavonoids: luteolin-7-O-glucoside, apigenin-7-O-glucoside, luteolin, apigenin, rutin and quercetin, which were studied using LC–MS/MS technique. LC–MS/MS analysis showed a noticeable content of natural products according to which the examined J. sibirica Burgsdorf. species could well be regarded as a promising new source of bioactive natural compounds, which can be used both as a food supplement and a remedy.     

Glucosinolates profile of Brassica rapa L. subsp. Sylvestris L. Janch. var. esculenta Hort

Glucosinolates in different ecotypes of Brassica rapa L. subsp. sylvestris L. Janch. var. esculenta Hort. widely distributed in Southern Italy and locally known as “friariello” and “cima di rapa”, were characterized and their glucosinolate composition was compared with that of broccoli (Brassica oleracea L. var. italica).     

Composition of the essential oil of Daucus gingidium L. ssp. gingidium

The essential oils obtained from leaves and fruits of Daucus gingidium ssp. gingidium have been studied. The main constituents of the essential oil from the leaves were sabinene (26.8%), α-pinene (10.8%), germacrene D (6.9%) and limonene (5.7%). Sabinene (60.6%) was the main compound identified in the essential oil of the fruits, followed by α-pinene (12.2%) and 4-terpineol (5.4%). Furthermore, qualitative and quantitative considerations about differences with literature data on Daucus carota have been made in order to confirm the species status of D. gingidium.     

Chemical analysis of French beans (Phaseolus vulgaris L.) by headspace solid phase microextraction (HS-SPME) and simultaneous distillation/extraction (SDE)

Headspace Solid Phase Microextraction (HS-SPME) involving divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fibre and simultaneous distillation/extraction (SDE) techniques were applied to study the volatile and semi volatile compounds of thawed and cooked Phaseolus vulgaris L. A total of 104 compounds were detected by GC and GC/MS. Thereof, 76 compounds were identified for the first time in this species. The major differences between HS-SPME and SDE were found in the content of identified alcohols (23.62% SDE versus 62.20% SPME), terpenoids (39.15% SDE versus 2.45% SPME), heterocyclic compounds (13.78% SDE versus 1.21% SPME), hydrocarbons (2.22% SDE versus 13.87% SPME) and esters (0.98% SDE versus 12.98% SPME). The SPME technique was found to be useful for rapid and routine quality controls of thawed French beans, while SDE is favourable to study the entire set of flavour volatiles in the corresponding cooked samples.     

Optimization of the production of Momordica charantia L. Var. abbreviata Ser. protein hydrolysates with hypoglycemic effect using Alcalase

Momordica charantia L. Var. abbreviata Ser. protein was hydrolyzed using six different proteases. The results showed Alcalase 2.4L to have the best hydrolyzing capacity, followed by Pancreatin. In addition, Alcalase hydrolysate had stronger hypoglycemic effect than that of Pancreatin hydrolysate at the same dose. Alcalase was chosen to produce M. charantia L. Var. abbreviata Ser. protein hydrolysates (MCPHs) with hypoglycemic effect. Response surface methodology (RSM) was applied to optimize the hydrolysis conditions using Alcalase. Model equation was proposed with regard to the effect of enzyme/substrate ratio, pH and temperature. The optimum values for enzyme/substrate ratio, pH and temperature were found to be 2.37%, 9.2 and 57 °C respectively.     

Isolation and characterisation of the sesquiterpene lactones from Lactuca sativa L var. anagustata

Lactuca sativa L var. anagustata is widely used as both a delicious vegetable and a traditional medicine in China. Chemical investigation of the methanolic extract of L. sativa L var. anagustata has now led to the isolation of three new sesquiterpenes, together with eight known ones. All the compounds were isolated by chromatography on a silica gel column and preparative thin-layer chromatography (PTLC). Their structures were elucidated by means of spectroscopic methods, including 2D-NMR experiments. Cytotoxicity of the new compounds was assayed against selected cancer cell lines, including the human epithelial carcinoma (HeLa) and human colon carcinoma (HCT-116) cell lines. Radical-scavenging activities of the seven compounds were determined by DPPH radical-scavenging assay.