Antioxidant Capacity and Chemical Profiles of Satureja montana L. Honey: Hotrienol and Syringyl Derivatives as Biomarkers

The present study is focused on the antioxidant capacity and chemical profiling of eight Croatian Satureja montana L. honey samples. Among the 20 compounds obtained by headspace solid‐phase microextraction (HS‐SPME) and identified by GC‐FID and GC/MS analyses, hotrienol was predominant (75.9–81.7%). The honey matrix volatile/semivolatile profile was investigated by ultrasonic solvent extraction (USE) followed by GC‐FID and GC/MS analyses. The major compounds identified by this latter method were the sinapic‐acid derivatives methyl syringate (36.2–72.8%) and syringaldehyde (2.2–43.1%). Direct, targeted HPLC‐DAD analyses of the native honey samples revealed the presence of methyl syringate (7.10–39.60 mg/kg) and syringic acid (0.10–1.70 mg/kg). In addition, the total phenolic content of the samples was determined by the Folin? Ciocalteu assay (311.0–465.9 mg GAE/kg), and the antioxidant capacity was evaluated by the DPPH radical‐scavenging activity (0.5–1.0 mmol TEAC/kg) and the ferric reducing antioxidant power (2.5–5.1 mmol Fe²⁺/kg).     

Volatile Composition Screening of Salix spp. Nectar Honey: Benzenecarboxylic Acids,Norisoprenoids, Terpenes,and Others

Salix spp. nectar honey volatiles of Croatian origin were analyzed by headspace solid‐phase microextraction (HS‐SPME) and ultrasonic solvent extraction (USE), followed by gas chromatography and mass spectrometry (GC, GC/MS). Isolated volatiles were found in the honey headspace and extracts with almost exclusive distribution of several abundant compounds (e.g., phenylacetic acid, pinocembrin, 8‐hydroxy‐4,7‐dimethylcoumarin, and 3‐hydroxy‐trans‐β‐damascone in the extracts, or safranal and lilac alcohols in the headspace). Comparison with Croatian Salix spp. honeydew honey revealed similarities regarding distribution of important shikimate pathway derivatives (e.g., high percentage of phenylacetic acid) and several norisoprenoids (α‐isophorone and 4‐oxoisophorone). On the other hand, distinct features of this honey were occurrence of compounds such as pinocembrin, 8‐hydroxy‐4,7‐dimethylcoumarin, phenylacetonitrile, norisoprenoids (major ones: 3‐hydroxy‐trans‐β‐damascenone and trans‐β‐damascone), more pronounced variability of linalool‐derived compounds, as well as the abundance of 3‐methylpropanoic acid, 3‐methylbutanoic acid, 2‐methylpentanoic acid, and 3‐methylpentan‐1‐ol.     

Bioorganic Diversity of Rare Coriandrum sativum L. Honey: Unusual Chromatographic Profiles Containing Derivatives of Linalool/Oxygenated Methoxybenzene

The compounds responsible for highly individual aroma profile of Coriandrum sativum L. honey were isolated by headspace solid‐phase microextraction (HS‐SPME; used fibers: A: polydimethylsiloxane (PDMS)/divinylbenzene (DVB) and B: divinylbenzene/carboxen/polydimethylsiloxane), as well as ultrasonic solvent extraction (USE; used solvents: A: pentane/Et₂O 1 : 2 (v/v) and B: CH₂Cl₂) and analyzed by gas chromatography (GC) and mass spectrometry (MS). Unusual chromatographic profiles were obtained containing derivatives of linalool/oxygenated methoxybenzene. trans‐Linalool oxide (11.1%; 14.6%) dominated in the headspace, followed by other linalool derivatives (such as cis/trans‐anhydrolinalool oxide (5.0%; 5.9%), isomers of lilac aldehyde/alcohol (14.9%; 13.8%) or p‐menth‐1‐en‐9‐al (15.6%; 18.5%)), octanal, and several low‐molecular‐weight esters. The major compounds in the solvent extracts were oxygenated methoxybenzene derivatives such as 3,4,5‐trimethoxybenzyl alcohol (26.3%; 24.7%), methyl syringate (23.8%; 11.7%), and 3,4‐dimethoxybenzyl alcohol (5.6%; 13.9%). Another group of abundant compounds in the extracts were derivatives of linalool (e.g., (E)/(Z)‐2,6‐dimethylocta‐2,7‐diene‐1,6‐diol (17.8%; 16.1%)). Among the compounds identified, cis/trans‐anhydrolinalool oxides and 3,4,5‐trimethoxybenzyl alcohol can be useful as chemical markers of coriander honey.     

Screening of Polish Fir Honeydew Honey Using GC/MS,HPLC‐DAD,and Physical‐Chemical Parameters: Benzene Derivatives and Terpenes as Chemical Markers

GC/MS of headspace solid phase micro extraction (HS‐SPME) and solvent extractives along with targeted HPLC‐DAD of Polish fir (Abies alba Mill .) honeydew honey (FHH), were used to determine the chemical profiles and potential markers of botanical origin. Additionally, typical physical‐chemical parameters were also assigned. The values determined for FHH were: conductivity (1.2 mS/cm), water content (16.7 g/100 g), pH (4.5), and CIE chromaticity coordinates (L* = 48.4, a* = 20.6, b* = 69.7, C* = 72.9, and h° = 73.5). FHH contained moderate‐high total phenolic content (533.2 mg GAE/kg) and antioxidant activity (1.1 mmol TEAC/kg) and (3.2 mmol Fe²⁺/kg) in DPPH and FRAP assays. The chemical profiles were dominated by source plant‐originated benzene derivatives: 3,4‐dihydroxybenzoic acid (up to 8.7 mg/kg, HPLC/honey solution), methyl syringate (up to 14.5%, GC/solvent extracts) or benzaldehyde (up to 43.7%, GC/headspace). Other markers were terpenes including norisoprenoid (4‐hydroxy‐3,5,6‐trimethyl‐4‐(3‐oxobut‐1‐enyl)cyclohex‐2‐en‐1‐one, up to 20.3%, GC/solvent extracts) and monoterpenes, mainly linalool derivatives (up to 49%, GC/headspace) as well as borneol (up to 5.9%, GC/headspace). The application of various techniques allowed comprehensive characterisation of FHH. 4‐Hydroxy‐3,5,6‐trimethyl‐4‐(3‐oxobut‐1‐enyl)cyclohex‐2‐en‐1‐one, coniferyl alcohol, borneol, and benzaldehyde were first time proposed for FHH screening. Protocatechuic acid may be a potential marker of FFH regardless of the geographical origin.     

The Volatile Profiles of a Rare Apple (Malus domestica Borkh.) Honey: Shikimic Acid‐Pathway Derivatives,Terpenes, and Others

The volatile profiles of rare Malus domestica Borkh . honey were investigated for the first time. Two representative samples from Poland (sample I) and Spain (sample II) were selected by pollen analysis (44–45% of Malus spp. pollen) and investigated by GC/FID/MS after headspace solid‐phase microextraction (HS‐SPME) and ultrasonic solvent extraction (USE). The apple honey is characterized by high percentage of shikimic acid‐pathway derivatives, as well as terpenes, norisoprenoids, and some other compounds such as coumaran and methyl 1H‐indole‐3‐acetate. The main compounds of the honey headspace were (sample I; sample II): benzaldehyde (9.4%; 32.1%), benzyl alcohol (0.3%; 14.4%), hotrienol (26.0%, 6.2%), and lilac aldehyde isomers (26.3%; 1.7%), but only Spanish sample contained car‐2‐en‐4‐one (10.2%). CH₂Cl₂ and pentane/Et₂O 1 : 2 (v/v) were used for USE. The most relevant compounds identified in the extracts were: benzaldehyde (0.9–3.9%), benzoic acid (2.0–11.2%), terpendiol I (0.3–7.4%), coumaran (0.0–2.8%), 2‐phenylacetic acid (2.0–26.4%), methyl syringate (3.9–13.1%), vomifoliol (5.0–31.8%), and methyl 1H‐indole‐3‐acetate (1.9–10.2%). Apple honey contained also benzyl alcohol, 2‐phenylethanol, (E)‐cinnamaldehyde, (E)‐cinnamyl alcohol, eugenol, vanillin, and linalool that have been found previously in apple flowers, thus disclosing similarity of both volatile profiles.     

First Report on Rare Unifloral Honey of Endemic Moltkia petraea (Tratt.) Griseb. from Croatia: Detailed Chemical Screening and Antioxidant Capacity

Rare Moltkia petraea (Tratt .) Griseb . honey from Croatia was first time characterised. The spectrophotometric assays on CIE L*a*b*C_ab*h_ab° colour coordinates, total phenol content and antioxidant capacity (FRAP , CUPRAC , DPPH ^? and ABTS ^?+ assays) determined higher honey values generally close to dark honeys ranges. Headspace solid‐phase microextraction (HS ‐SPME ) on two fibres after GC ‐FID and GC /MS revealed the major compounds 2‐phenylacetaldehyde (12.8%; 15.6%), benzaldehyde (11.1%; 10.0%), octane (9.3%; 7.6%), nonane, propan‐2‐one, pentan‐2‐one, pentanal and nonanal (4.9%; 14.5%). Ultrasonic solvent extraction (USE ) mainly isolated non‐specific higher molecular compounds characteristic of the comb environment. Targeted HLPC ‐DAD analysis of the honey determined higher concentration of phenylalanine (212.08 mg/kg) and lumichrome (16.25 mg/kg) along with tyrosine and kojic acid. The headspace composition (chemical fingerprint) and high concentration of lumichrome can be considered particular for M . petraea honey.     

Volatile compounds of Asphodelus microcarpus Salzm. et Viv. Honey obtained by HS-SPME and USE analyzed by GC/MS

Chemical analysis of Asphodelus microcarpus Salzm. et Viv. honey is of great importance, since melissopalynology does not allow the unambiguous determination of its botanical origin. Therefore, the volatile compounds of eight unifloral asphodel honeys have been investigated for the first time. The honey extracts were obtained by headspace solid-phase microextraction (HS-SPME) and ultrasonicsolvent extraction (USE) and analyzed by GC and GC/MS. In the honey headspace, 31 volatile compounds were identified with high percentages of 2-phenylacetaldehyde (2; 14.8–34.7%), followed by somewhat lower percentages of methyl syringate (1; 10.5–11.5%). Compound 2 is not a specific marker of the botanical origin of the honey, but its high percentage can be emphasized as headspace characteristic of asphodel honey. The extraction solvent for all the samples was selected after extracting a representative sample with pentane, Et(2)O, pentane/Et(2)O 1:2 (v/v), and CH(2)Cl(2) . Compound 1 was the major constituent of all the USE extracts (46.8–87.0%). According to these preliminary results, all the honey samples were extracted by USE with the solvent pentane/Et(2)O 1:2. A total of 60 volatile compounds were identified with 1 as predominant compound (69.4–87.0%), pointing out 1 as Asphodelus honey volatile marker.     

Comprehensive Study of Mediterranean (Croatian) Propolis Peculiarity: Headspace,Volatiles, Anti‐Varroa‐Treatment Residue,Phenolics, and Antioxidant Properties

Eight propolis samples from Croatia were analyzed in detail, to study the headspace, volatiles, anti‐Varroa‐treatment residue, phenolics, and antioxidant properties. The samples exhibited high qualitative/quantitative variability of the chemical profiles, total phenolic content (1,589.3–14,398.3 mg GAE (gallic acid equivalent)/l EtOH extract), and antioxidant activity (11.1–133.5 mmol Fe²⁺/l extract and 6.2–65.3 mmol TEAC (Trolox^® equivalent antioxidant capacity)/l extract). The main phenolics quantified by HPLC‐DAD at 280 and 360 nm were vanillin, p‐coumaric acid, ferulic acid, chrysin, galangin, and caffeic acid phenethyl ester. The major compounds identified by headspace solid‐phase microextraction (HS‐SPME), simultaneous distillation extraction (SDE), and subsequent GC‐FID and GC/MS analyses were α‐eudesmol (up to 19.9%), β‐eudesmol (up to 12.6%), γ‐eudesmol (up to 10.5%), benzyl benzoate (up to 28.5%), and 4‐vinyl‐2‐methoxyphenol (up to 18.1%). Vanillin was determined as minor constituent by SDE/GC‐FID/MS and HPLC‐DAD. The identified acaricide residue thymol was ca. three times more abundant by HS‐SPME/GC‐FID/MS than by SDE/GC‐FID/MS and was not detected by HPLC‐DAD.     

NMR,HS‐SPME‐GC/MS,and HPLC/MSn Analyses of Phytoconstituents and Aroma Profile of Rosmarinus eriocalyx

In this work, a comprehensive study on the chemical constituents of the aerial parts of Rosmarinus eriocalyx (Lamiaceae), an aromatic shrub traditionally consumed as a food and herbal remedy in Algeria, is presented. The aroma profile was analysed by headspace solid phase microextraction (HS‐SPME) coupled with gas chromatography‐mass spectrometry (GC/MS), whereas the crude extract constituents were analyzed by ¹H‐NMR and by high performance liquid chromatography coupled with mass spectrometry (HPLC/MSⁿ). Thirty‐nine volatile compounds, most of them being monoterpenes, have been identified, with camphor, camphene, and α‐pinene as the most abundant constituents. ¹H‐NMR analysis revealed the presence of phenolic compounds and betulinic acid while HPLC/MSⁿ allowed the identification of glycosilated and aglyconic flavonoids as well as phenylpropanoid derivatives. Some of these constituents, namely as betulinic acid, rosmanol, and cirsimaritin were reported for the first time in R. eriocalyx.     

Validation of a quantitative assay of arbutin using gas chromatography in Origanum majorana and Arctostaphylos uva‐ursi extracts

Introduction – Arbutin is a skin‐whitening agent that occurs naturally in the bark and leaves of various plants. It is commonly quantified in plant extracts and skin‐whitening products by HPLC. Objective – To develop an alternative gas chromatographic method for the separation and quantification of arbutin in Origanum majorana and Arctostaphylos uva‐ursi extracts. Methodology – N,O‐Bis(trimethylsilyl)acetamide and trimethylchlorosilane were used as silylation reagents, and the gas chromatographic separation of silylated extracts and standards was performed using a DB‐5 narrow bore column. GC‐MS was used for the compound identification, and the quantification was carried out by GC‐FID. The quantitative results were compared with those of HPLC analysis. Results – The developed method gave a good sensitivity with linearity in the range 0.33–500 mg/mL and recovery >98%, allowing the quantification of arbutin in O. majorana and A. uva‐ursi extracts. The relative standard deviations (RSD) relating to intra‐day and inter‐day precision were <0.002% and <4.8%, respectively. The GC results correlated well with those obtained by HPLC analysis. Conclusion – The analysis of marjoram and bearberry samples showed that the established GC method was rapid, selective, and demonstrated that arbutin could be screened alternatively by gas chromatography. Copyright © 2009 John Wiley & Sons, Ltd.     

Chemical Diversity and Antimicrobial Activity of Volatile Compounds from Zanthoxylum zanthoxyloides Lam. according to Compound Classes,Plant Organs and Senegalese Sample Locations

The chemical diversity of Zanthoxylum zanthoxyloides growing wild in Senegal was studied according to volatile compound classes, plant organs and sample locations. The composition of fruit essential oil was investigated using an original targeted approach based on the combination of gas chromatography (GC) and liquid chromatography (LC) both coupled with mass spectrometry (MS). The volatile composition of Z. zanthoxyloides fruits exhibited relative high amounts of hydrocarbon monoterpenes (24.3 – 55.8%) and non‐terpenic oxygenated compounds (34.5 – 63.1%). The main components were (E)‐β‐ocimene (12.1 – 39%), octyl acetate (11.6 – 21.8%) and decanol (9.7 – 15.4%). The GC and GC/MS profiling of fruit essential oils showed a chemical variability according to geographical locations of plant material. The LC/MS/MS analysis of fruit oils allowed the detection of seven coumarins in trace content. The chemical composition of fruit essential oils was compared with volatile fractions of leaves and barks (root and trunk) from the same plant station. Hexadecanoic acid, germacrene D and decanal were identified as the major constituents of leaves whereas the barks (root and trunk) were dominated by pellitorine (85.8% and 57%, respectively), an atypic linear compound with amide group. The fruit essential oil exhibited interesting antimicrobial activities against Staphylococcus aureus and Candida albicans, particularly the alcohol fraction of the oil.     

Profiles of the Essential Oils and Headspace Analysis of Volatiles from Mandragora autumnalis Growing Wild in Tunisia

Mandragora autumnalis Bertol . (Solanaceae family), synonym of M. officinalis Mill ., occurs in North Africa and grows natively in Northern and Central Tunisia, in humid to sub‐arid climates. The ripe fruits of mandrake are odiferous with a particular, indescribable, specific odor, shared, to a lesser extent, by the leaves and roots. We carried out an investigation of the essential oils (EOs) and of the aromatic volatiles emitted by fresh leaves, roots and ripe fruits of M. autumnalis growing wild in Central Tunisia. The EOs were obtained from freshly collected plant material by hydrodistillation, while the volatile emissions from the powdered M. autumnalis tissues were sampled by headspace solid phase microextraction (HS‐SPME); both types of samples were analyzed by gas chromatography‐mass spectrometry (GC/MS). Fifty‐one compounds representing 96.2–98.6 % of the total oil compositions were identified in the three tissues and belonged to different chemical classes specifically in 16 esters, 12 alcohols, 12 hydrocarbons, 6 ketones, 3 aldehydes and 3 acids. The main constituents were pentadecanoic acid (34.2 %) and hexadecanol (26.3 %). A total of 78 volatile compounds emanating from M. autumnalis tissues, representing 94.1–96.4 % of the total volatile compositions, were identified: 22 esters, 11 alcohols, 9 aldehydes, 14 ketones, 7 nitrogen, 10 hydrocarbons, 2 lactones, 1 sulfur and 2 ethers. Ethyl hexanoate (12.3 %) and 1,3‐butanediol (12.3 %) were at the highest relative percentages. This study characterizes and distinguishes M. autumnalis from Tunisia and attributes the compounds responsible for the intoxicating and particular odor of fruits. Chemosystematic of Mandragora autumnalis based on the identification of essential oils and headspace volatiles of each of its organ can be used to characterize this species according to its geographic distribution.     

Olfactory response of Anastrepha striata (Diptera: Tephritidae) to guava and sweet orange volatiles

The behavioral responses of virgin and mated female Anastrepha striata Schiner (Diptera: Tephritidae) to guava (Psidium guajava L.) or sweet orange (Citrus sinensis L.) were evaluated separately using multilure traps in two‐choice tests in field cages. The results showed that flies were more attracted to guava and sweet orange volatiles than to control (unbaited trap). The physiological state (virgin or mated) of females did not affect their attraction to the fruit volatiles. Combined analysis of gas chromatography coupled with electroantennography (GC‐EAD) of volatile extracts of both fruits showed that 1 and 6 compounds from orange and guava, respectively elicited repeatable antennal responses from mated females. The EAD active compounds in guava volatile extracts were identified by gas chromatography‐mass spectrometry (GC‐MS) as ethyl butyrate, (Z)‐3‐hexenol, hexanol, ethyl hexanoate, hexyl acetate, and ethyl octanoate. Linalool was identified as the only antennal active compound in sweet orange extracts. In field cage tests, there were no significant differences between the number of mated flies captured by the traps baited with guava extracts and the number caught by traps baited with the 6‐component blend that was formulated according to the relative proportions in the guava extracts. Similar results occurred when synthetic linalool was evaluated against orange extracts. From a practical point of view, the compounds identified in this study could be used for monitoring A. striata populations.     

GC-MS analysis of headspace and liquid extracts for metabolomic differentiation of citrus Huanglongbing and zinc deficiency in leaves of 'Valencia' sweet orange from commercial groves

Introduction – Citrus Huanglongbing (HLB) is considered the most destructive citrus disease worldwide. Symptoms‐based detection of HLB is difficult due to similarities with zinc deficiency. Objective – To find metabolic differences between leaves from HLB‐infected, zinc‐deficient, and healthy ‘Valencia’ orange trees by using GC‐MS based metabolomics. Methodology – Analysis based on GC‐MS methods for untargeted metabolite analysis of citrus leaves was developed and optimized. Sample extracts from healthy, zinc deficient, or HLB‐infected sweet orange leaves were submitted to headspace solid phase micro‐extraction (SPME) and derivatization treatments prior to GC‐MS analysis. Results – Principal components analysis achieved correct classification of all the derivatized liquid extracts. Analysis of variance revealed 6 possible biomarkers for HLB, of which 5 were identified as proline, β‐elemene, (‐)trans‐ caryophyllene, and α‐humulene. Significant (P < 0.05) differences in oxo‐butanedioic acid, arabitol, and neo‐inositol were exclusively detected in samples from plants with zinc deficiency. Levels of isocaryophyllen, α‐selinene, β‐selinene, and fructose were significantly (P < 0.05) different in healthy leaves only. Conclusion – Results suggest the potential of using identified HLB biomarkers for rapid differentiation of HLB from zinc deficiency. Copyright © 2010 John Wiley & Sons, Ltd.     

Enantiomer Distribution of Major Chiral Volatile Organic Compounds in Selected Types of Herbal Honeys

In this article, volatile organic compounds in 14 honey samples (rosemary, eucalyptus, orange, thyme, sage, and lavender) were identified. Volatile organic compounds were extracted using a solid phase microextraction method followed by gas chromatography connected with mass spectrometry analysis. The studied honey samples were compared based on their volatile organic compounds composition. In total, more than 180 compounds were detected in the studied samples. The detected compounds belong to various chemical classes such as terpenes, alcohols, acids, aldehydes, ketones, esters, norisoprenoids, benzene and furane derivatives, and organic compounds containing sulfur and nitrogen heteroatom. Ten chiral compounds (linalool, trans‐linalool oxide, cis‐linalool oxide, 4‐terpineol, α‐terpineol, hotrienol, and four stereoisomers of lilac aldehydes) were selected for further chiral separation. Chirality 26:670‐674, 2014. © 2014 Wiley Periodicals, Inc.     

Volatile Compounds of Viola odorata Absolutes: Identification of Odorant Active Markers to Distinguish Plants Originating from France and Egypt

Absolutes isolated from Viola odorata leaves, valuable materials for the flavor and fragrance industry, were studied. Violets are mainly cultivated in France and Egypt and extracted locally. The absolutes of the two origins showed different olfactory profiles both in top and heart notes, as evidenced by sensory analysis. The aims of this study were i) to characterize the volatile compounds, ii) to determine the odorant‐active ones, and iii) to identify some markers of the plant origin. Two complementary analytical methods were used for these purposes, i.e., headspace solid‐phase microextraction (HS‐SPME) using different fiber coatings followed by GC/MS analysis and gas chromatography – olfactometry/mass spectrometry (GC‐O/MS) applied to violet leaf extracts. From a total of 70 identified compounds, 61 have never been reported so far for this species, 17 compounds were characterized by both techniques (with seven among them known from the literature), 23 compounds were solely identified by HS‐SPME GC/MS (among them only two being already mentioned as components of violet absolutes in the literature), and, finally, 30 compounds were only identified by GC‐O/MS. According to the HS‐SPME GC/MS analyses, ethyl hexanoate and (2E,6Z)‐nona‐2,6‐dienol were specific volatile compounds of the sample with French origin, while (E,E)‐hepta‐2,4‐dienal, hexanoic acid, limonene, tridecane, and eugenol were specific of the samples with Egyptian origin. Additional compounds that were not detected by HS‐SPME GC/MS analysis were revealed by GC‐O analyses, some of them being markers of origin. Pent‐1‐en‐3‐ol, 3‐methylbut‐2‐enal, 2‐methoxy‐3‐(1‐methylethyl)pyrazine, 4‐ethylbenzaldehyde, β‐phenethyl formate, and 2‐methoxy‐3‐(2‐methylpropyl)pyrazine revealed to be odorant markers of the French sample, whereas cis‐rose oxide, trans‐rose oxide, and 3,5,5‐trimethylcyclohex‐2‐enone were odorant markers of the Egyptian samples.     

Volatile compounds emitted by Triatoma dimidiata,a vector of Chagas disease: chemical analysis and behavioural evaluation

In this study, we evaluated the responses of Triatoma dimidiata Latreille (Hemiptera: Reduviidae) to volatiles emitted by conspecific females, males, mating pairs and metasternal gland (MG) extracts with a Y‐tube olfactometer. The volatile compounds released by mating pairs and MGs of T. dimidiata were identified using solid‐phase microextraction and coupled gas chromatography‐mass spectrometry (GC‐MS). Females were not attracted to volatiles emitted by males or MG extracts; however, they preferred clean air to their own volatiles or those from mating pairs. Males were attracted to volatiles emitted by males, females, mating pairs, pairs in which the male had the MG orifices occluded or MG extracts of both sexes. However, males were not attracted to volatiles emitted by pairs in which the female had the MG orifices occluded. The chemical analyses showed that 14 and 15 compounds were detected in the headspace of mating pairs and MG, respectively. Most of the compounds identified from MG except for isobutyric acid were also detected in the headspace of mating pairs. Both females and males were attracted to octanal and 6‐methyl‐5‐hepten‐2‐one, and males were attracted to 3,5‐dimethyl‐2‐hexanol. Males but not females were attracted to a seven‐compound blend, formulated from compounds identified in attractive MG extracts.     

Chemodiversity and Antiproliferative Activity of the Essential Oil of Schinus molle Growing in Jordan

The leaves and unripe and fully‐grown fruits of Schinus molle were collected from three geographical regions of Jordan: Amman (the Mediterranean), Madaba (Irano‐Turanean), and Sahab (Saharo‐Arabian). The hydrodistilled volatile oils of fresh and dried leaves and fruits were analyzed by gas chromatography‐mass spectrometry (GC/MS). The actual composition of the emitted volatiles was determined using Solid Phase Micro‐Extraction (SPME). α‐ and β‐Phellandrenes were the major components in all the analyzed samples. Quantitative differences were observed in the obtained essential oils (0.62–5.25 %). Additionally, cluster analysis was performed. Biologically, the antiproliferative activity of the essential oil, ethanol, and water extracts of the fruits and leaves was screened on Caco2, HCT116, MCF7, and T47D cell lines. The essential oil and ethanol extracts exhibited a dose‐dependent inhibition of cell growth with IC₅₀ ranging between 21 and 65 μg/mL. The water extract did not exhibit any antiproliferative activity against the investigated cell lines.     

Pollen aroma fingerprint of two sunflower (Helianthus annuus L.) genotypes characterized by different pollen colors

Samples of fresh pollen grains, collected from capitula in full bloom from two genotypes of sunflower (Helianthus annuus L.) and characterized by a different color, i.e., white‐cream (WC) and orange (O), were analyzed by the HS‐SPME (headspace solid phase microextraction)/GC/MS technique. This study defined for the first time the fingerprint of the sunflower pollen, separated from the disc flowers, to define its contribution to the inflorescence aroma. In the GC/MS fingerprints of the WC and O genotypes, 61 and 62 volatile compounds were identified, respectively. Monoterpene hydrocarbons (34% in O vs. 28% in WC) and sesquiterpene hydrocarbons (37% in O vs. 31% in WC) were ubiquitous in all samples analyzed and represented the main chemical classes. α‐Pinene (21% in O vs. 20% in WC) and sabinene (11% in O vs. 6% in WC) were the dominant volatiles, but also a full range of aliphatic hydrocarbons and their oxygenated derivatives gave a decisive contribution to the aroma composition (10% in O vs. 12% in WC). In addition, dendrolasin (3% in O vs. 4% in WC) and some minor constituents such as (E)‐hex‐2‐en‐1‐ol (0.4% in O vs. 0.1% in WC) were pointed out not only for their contribution to the pollen scent, but also for their well‐known role in the plant ecological relationships. Having evaluated two pollen morphs with different carotenoid‐based colors, the study sought to highlight also the presence of some volatile precursors or derivatives of these pigments in the aroma. However, the pollen aroma of the two selected genotypes made a specific chemical contribution to the sunflower inflorescence scent without any influence on carotenoid derivatives.     

Isomerization of octadecapentaenoic acid (18:5n‐3) in algal lipid samples under derivatization for GC and GC‐MS analysis

During gas chromatography (GC) analysis of fatty acid (FA) composition of the dinoflagellate Gymnodinium kowalevskii, we found unex‐pectedly low and irreproducible content of all‐cis‐3,6,9,12,15‐octadecapentaenoic acid (18:5n‐3), which is an important chemotaxonomic marker of several classes of microalgae. We compared chromatographic behavior of 18:5n‐3 methyl ester and other GC derivatives obtained using different conventional methods of derivatization. The use of methods based on saponification or base‐catalyzed transesterification resulted in a mixture of double‐bond positional isomers of 18:5. On a SUPELCOWAX 10 column, the equivalent chain length (ECL) value for authentic 18:5n‐3 methyl ester was 20.22, whereas the main component after base‐catalyzed methylation had ECL 20.88. Attempts to prepare N‐acyl pyrrolidides or 4,4‐dimethyloxazoline (DMOX) derivatives of 18:5n‐3 also gave inadequate results. These derivatives also showed a main peak corresponding to isomerized 18:5. Mass spectra for both DMOX and pyrrolidide derivatives of this compound showed the base peak at m/z 139, probably corresponding to 2,6,9,12,15‐18:5 acid. Of all methods tested for methylation, only derivatization with 5% HCl or 1% sulphuric acid in methanol gave satisfactory results. Therefore, GC or GC‐mass spectrometry analyses of algal lipids containing 18:5n‐3 may be inaccurate when base‐catalyzed methods of FA derivatization are applied. The best and simplest way to avoid incorrect GC results is to use standard acid‐catalyzed methylation.