A review on chemical constituents of essential oils of Aframomum genus

Aframomum K.Schum is a genus native to Africa belonging to Zingiberaceae. Members of the genus Aframomum are the aromatic and perennial rhizomatous herbs. Many plant parts of Aframomum species contain essential oils, including fruits, seeds, leaves, stems, rhizomes, pods, husks, pericarps, limbos and leaf sheaths. The major constituents of Aframomum plants are mainly composed of sesquiterpene hydrocarbons, oxygenated monoterpenes, oxygenated sesquiterpenes and monoterpene hydrocarbons. The present work provides the comprehensive information regarding the volatile components of various Aframomum species.

Neuroprotective Effects of Black Pepper Cold-Pressed Oil on Scopolamine-Induced Oxidative Stress and Memory Impairment in Rats

Oxidative stress is usually associated with many neurodegenerative diseases. In this study, the gas chromatography–mass spectrometry (GC–MS) analysis of cold-pressed oil (CPO) from black pepper (Piper nigrum) fruits was performed and its neuroprotective effects were evaluated for the first time. The analysis of CPO revealed the presence of the lignan sesamin (39.78%), the alkaloid piperine (33.79%), the monoterpene hydrocarbons 3-carene (9.53%) and limonene (6.23%), and the sesquiterpene β-caryophyllene (10.67%). Black pepper hydrodistilled oil (HDO) was also comparatively analyzed by GC–MS to show the impact of oil isolation by two different methodologies on their components and class of compounds identified. HDO analysis revealed 35 compounds (99.64% of the total peak areas) mainly composed of monoterpene hydrocarbons (77.28%), such as limonene (26.50%), sabinene (21.36%), and β-pinene (15.53%), and sesquiterpene hydrocarbons (20.59%) represented mainly by β-caryophyllene (19.12%). Due to the low yield obtained for HDO (0.01% v/w), only CPO was chosen for the evaluation of its neuroprotective potential. Alzheimer-type dementia was induced in rats by scopolamine intraperitoneal injection (1.5 mg/kg/day) for seven days. CPO was administered orally (100 mg/kg) for a week before scopolamine administration and then concomitantly for another week. Donepezil (1 mg/kg, orally) was used as a reference drug. CPO administration significantly improved the rat behaviors as evaluated by the Morris water maze test, evident from prolongation in time spent in the platform quadrant (262.9%, compared to scopolamine) and increasing in the crossing time by 18.18% compared to the control group. The rat behavior tested by passive avoidance, showed prolongation in the step-through latency compared to control. Moreover, CPO significantly (p < 0.05) ameliorated the activities of antioxidant enzymes such as catalase, superoxide dismutase (SOD) and reduced malondialdehyde (MDA) equivalents by 22.48%, 45.41%, and 86.61%, respectively, compared to scopolamine. Furthermore, CPO administration decreased scopolamine-induced elevated acetylcholinesterase levels in rats’ hippocampi by 51.30%. These results were supported by histopathological and in silico molecular docking studies. Black pepper oil may be a potential antioxidant and neuroprotective supplement.

Comparison of Volatile Organic Compounds of Sideritis romana L. and Sideritis montana L. from Croatia

A study on the headspace volatile organic compounds (VOCs) profile of native populations of Sideritis romana L. and Sidertis montana L., Lamiaceae, from Croatia is reported herein, to elucidate the phytochemical composition of taxa from this plant genus, well-known for traditional use in countries of the Mediterranean and the Balkan region. Headspace solid-phase microextraction (HS-SPME), using divinylbenzene/carboxene/polydimethylsiloxane (DVB/CAR/PDMS) or polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber, coupled with gas chromatography-mass spectrometry (GC-MS) was applied to analyze the dried aerial parts of six native populations in total. Furthermore, principal component analysis (PCA) was conducted on the volatile constituents with an average relative percentage ≥1.0% in at least one of the samples. Clear separation between the two species was obtained using both fiber types. The VOCs profile for all investigated populations was characterized by sesquiterpene hydrocarbons, followed by monoterpene hydrocarbons, except for one population of S. romana, in which monoterpene hydrocarbons predominated. To our knowledge, this is the first report on the VOCs composition of natural populations of S. romana and S. montana from Croatia as well as the first reported HS-SPME/GC-MS analysis of S. romana and S. montana worldwide.

Assessment of the Suitability of Aromatic and High-Bitter Hop Varieties (Humulus lupulus L.) for Beer Production in the Conditions of the Małopolska Vistula Gorge Region

The aim of the study was to assess the yield of cones and the quality of six hop varieties (“Iunga”, “Lubelski”, “Sybilla”, “Magnum”, “Lomik”, “Marynka”) in terms of their suitability for beer production, under the conditions of the Małopolska Vistula Gorge Region (21°53′ E; 51°16′ N) (2015–2017). The scope of the research included the determination of the yield of cones and their physicochemical properties, as well as determination of the contents of hop resins and essential oils. In bitter varieties, the ratio of alpha-acids to beta-acids was stable, while, in aromatic varieties, it was variable. In the essential oils of the studied hop varieties, compounds with myrcene and α-humulene were identified and dominated the profiles. “Iunga”, “Sybilla”, “Lubelski”, and “Lomik” were rich in monoterpene hydrocarbons, mainly myrcene, while there was a bit more α-humulene in the “Marynka” variety. “Magnum” was characterized by an even distribution of monoterpenes and sesquiterpenes. The “Magnum variety turned out the most useful for the brewing industry in this region. The Małopolska Vistula Gorge Region is a region where hops not only achieve a high yield of cones, but also good-quality. The bitterness and aroma content of the hops in this region is high.

Bergamot Oil: Botany, Production, Pharmacology

Bergamot essential oil (BEO) is the result of the mechanical manipulation (cold pressing) of the exocarp (flavedo) of the hesperidium of Citruslimon (L.) Osbeck Bergamot Group (synonym Citrus × bergamia Risso & Poit.), resulting in the bursting of the oil cavities embedded in the flavedo and the release of their contents. It is chemically dominated by monoterpene hydrocarbons (i.e., limonene), but with significant percentages of oxygenated monoterpenes (i.e., linalyl acetate) and of non-volatile oxygen heterocyclic compounds (i.e., bergapten).

Composition of the Essential Oil and Insecticidal Activity of Launaea taraxacifolia (Willd.) Amin ex C. Jeffrey Growing in Nigeria

The rice weevil (Sitophilus oryzae) is a pest of stored grain products such as rice, wheat, and corn. Essential oils represent a green environmentally-friendly alternative to synthetic pesticides for controlling stored-product insect pests. Launaea taraxacifolia is a leafy vegetable plant found in several parts of Nigeria. The leaves are eaten either fresh as a salad or cooked as a sauce. The essential oil obtained from fresh leaves of L. taraxacifolia was obtained by hydrodistillation and analyzed by gas chromatography/mass spectrometry (GC-MS). Twenty-nine compounds were identified, accounting for 100% of the oil composition. The major component classes were monoterpene hydrocarbons (78.1%), followed by oxygenated monoterpenoids (16.2%), sesquiterpene hydrocarbons (2.1%), oxygenated sesquiterpenoids (0.3%), and non-terpenoid derivatives (3.3%). The leaf essential oil was dominated by monoterpene hydrocarbons including limonene (48.8%), sabinene (18.8%), and (E)-β-ocimene (4.6%), along with the monoterpenoid aldehyde citronellal (11.0%). The contact insecticidal activity of L. taraxacifolia essential oil against Sitophilus oryzae was carried out; median lethal concentration (LC50) values of topical exposure of L. taraxacifolia essential oil were assessed over a 120-h period. The LC50 values ranged from 54.38 μL/mL (24 h) to 10.10 µL/mL (120 h). The insecticidal activity of the L. taraxacifolia essential oil can be attributed to major components limonene (48.8%), sabinene (18.8%), and citronellal (11.0%), as well as potential synergistic action of the essential oil components. This result showed L. taraxacifolia essential oil may be considered as a useful alternative to synthetic insecticides.

Volatile organic compounds of Tilia cordata Mill. from Serbia, in terms of ecosystem services

It is considered that different plant organic compounds, known as phytoncides are creditable for positive effects of Forest therapy on human health. Ongoing pandemic has also put these compounds in research focus considering potential use for novel corona virus treatment. This research was conducted in order to examine the potential of Tilia cordata Mill. considering volatile organic compounds (VOCs) content for the use in Forest therapy. In order to determine qualitative and quantitative content of phytoncides, as well the variability among genotypes growing in the same environmental conditions, leaf samples from genotypes of T. cordata were collected from the Fruška gora (Serbia) during 2019. VOCs determined in fresh herbal material were analyzed by HeadspaceGC/MS and VOCs determined in essential oil were obtained by GC/MS. The results showed the presence of 17 different phytoncides (monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpene hydrocarbons, oxygenated sesquiterpenes, aliphatic compounds and diterpenes) in all tested genotypes. According to the mean values of the obtained results, the most abundant classes of phytoncides among the examined genotypes were monoterpene hydrocarbons (87.05), followed by aliphatic compounds (36.59) and oxygenated sesquiterpenes (34.60). The highest coefficient of variation (CV) among phytoncide content in tested T. cordata genotypes has been observed within oxygenated monoterpenes (43.12%), sesquiterpene hydrocarbons (28.18%), and diterpenes (27.04%). Some individual monoterpene hydrocarbons, such as o-cymene (19.92%) and a-pinene (17.40%) had the highest CV in terms of its presence in analyzed genotypes. In addition, the principal component analysis (PCA) showed more notable clustering within the VOCs determined in essential oil in comparison to VOCs determined in fresh herbal material. Considering the phytoncide content detected in T. cordata leaves, this species has high potential for the use in human health improvement within Forest therapy.

Phytochemical analysis of volatiles and biological activities of Chaerophyllum bulbosum L. essential oils

The present study reports for the first time the chemical composition of the headspace volatiles (HS) and essential oils obtained from fresh Chaerophyllum bulbosum roots and aerial parts, as well as biological activities of the essential oils. Generally, monoterpene hydrocarbons were found to be the main class of all investigated samples, with (E)-?-ocimene being the most abundant component. The results of antibacterial assay showed that both investigated samples exhibit bactericidal activity against two tested Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis subs. spizizeni) while they were inactive against tested Gram-negative bacteria (Escherichia coli and Salmonella abony). Regarding the antioxidant activity, it was found that the essential oils showed low antioxidant capacities in comparison with standard antioxidant compounds (such as butylated hydroxytoluene). The obtained results were expected given the fact that the main components in both samples were monoterpene hydrocarbons.

Terpenes and n-Alkanes in Needles of Pinus cembra

Simultaneous hydrodistillation and extraction of Pinus cembra needles from Slovakia was done (via Likens Nickerson apparatus) for the first time. In essential oil extracts 55 compounds were identified, comprising 99.6% of the extract. The most abundant were monoterpene hydrocarbons (71.0%). In the terpene profile α-pinene, limonene/β-phellandrene, germacrene D, β-pinene, and δ-cadinene dominated (53.2%, 11.4%, 9.4%, 4.6%, and 4.3%, respectively). Seven new compounds for P. cembra, such as methyl daniellate (0.5%), 1,8 cineole (0.2%) and trans-cadina-1(6),4-diene (0.2%), etc. were found. In needle cuticular wax of P. cembra the amount of nonacosan-10-ol was 75.8%. n-Alkanes ranged from C20 to C35 with the most dominant C31, C 29 and C33 (33.4%, 16.9%, and 9.6%, resp.). Differences in terpene profiles between Slovakian and Greece from one side and Romanian and Polish cembran pines on the other side could be the consequence of its disjuncted areal in Carpathian Mountains caused by glaciation and survival of species in different ecological niches. Obtained differences in n-alkane profiles among our and literature results could be the consequence of different age of trees.