Naturally Occurring Terpenes:A Promising Class of Organic Molecules to Address Influenza Pandemics

Since the olden times,infectious diseases have largely affected human existence.The newly emerged infections are excessively caused by viruses that are largely associated with mammal reservoirs.The casualties of these emergencies are significantly influenced by the way human beings interact with the reservoirs,especially the animal ones.In our review we will consider the evolutionary and the ecological scales of such infections and their consequences on the public health,with a focus on the pathogenic influenza A virus.The nutraceutical properties of fungal and plant terpene-like molecules will be linked to their ability to lessen the symptoms of viral infections and shed light on their potential use in the development of new drugs.New challenging methods in antiviral discovery will also be discussed in this review.The authors believe that pharmacognosy is the“wave of future pharmaceuticals”,as it can be continually produced and scaled up under ecofriendly requirements.Further diagnostic methods and strategies however are required to standardise those naturally occurring resources.

Evaluation of Terpenes’Degradation Rates by Rumen Fluid of Adapted and Non-adapted Animals

The aim of the present study was to evaluate terpenes degradation rate in the rumen fluid from adapted and non-adapted animals.Four castrated healthy animals,two rams and two bucks,were used.Animals were daily orally dosed for 2 weeks with 1 g of each of the following terpenes,α-pinene,limonene andβ-caryophyllene.At the end of each week,rumen fluid(RF)samples were assayed in vitro for their potential to degrade terpenes over time.For each animal,a 10 mL reaction medium(RM)at a ratio 1:9(v/v)was prepared and a terpenes solution at a concentration of 100μg/ml each,was added in each RM tube.Tubes were incubated at 39℃ under anaerobic conditions and their contents sampled at 0,2,4,8,21 and 24 h.RF could degrade terpenes as it was shown by the significantly(P<0.05)higher overall degradation rates.Individual terpene degradation rates,were significantly(P<0.05)higher in week 5 for limonene and marginally(P=0.083)higher also in week 5 forα-pinene.In conclusion,the findings of the present preliminary study suggest that terpenes can be degraded in the rumen fluid.

Terpenes of the Essential Oil from Ipomoea alba Leaf in Response to Herbivore and Mechanical Injuries

There is no doubt that the chemical composition of plants,including norvolatile and volatile compounds,is widely affected by abiotic and biotic stress.Plants are able to biosynthesize a variety of secondary metabolites against actions of natural enemies,such as herbivores,fungus,virus and bacteria.The present study revealed that the chemical compositions of leaf essential oils from Ipomoea alba underwent quantitative and qualitative alterations both when infested with the grasshopper Elaeochlora trilineata and mechanically damaged.Grasshopper attack and mechanical wounding induced the biosynthesis of nine volatile compounds in leaves of I.alba:cumene,α-ylangene,β-panasinsene,β-gurjunene aromadendrene,β-funebrene,spirolepechinene,cubenol and sclareolide.The amount of germacrene D(33.2%to 20.4%)decreased when the leaves were mechanically damaged;but when the leaves were attacked by a grasshopper,the germacrene D increased from 33.2%to 39.4%.The results showed that I.alba leaves clearly responded to abiotic and biotic stress and contribute to an understanding of plant responses to stress conditions.

Image Acquisition and Parameter Calculations for Optimization of the Automatic Identification of Terpenes in a Combined Laser Thin Film Extract

In this work, we propose an original approach to the thin-layer identification of secondary metabolites (terpenes) based on the acquisition of multicomponent images integrating terpenes to be identified. Its principle consists initially of segmentation by region of each component of the image based on the attribute tuples or colors of each region of the digital image. Then we proceeded to the calculations of region parameters such as standard deviation, entropy, average pixel color, eccentricity from an algorithm on the matlab software. These values allowed us to build a database. Finally, we built an algorithm for identifying secondary metabolites (terpenes) on the basis of these data. The relevance of our method of identifying or recognizing terpenes has been demonstrated compared to other methods, such as the one based on the calculation of frontal ratios which cannot discriminate between two terpenes having the same frontal ratio. The robustness of our method with respect to the identification of linalool, limonene was tested.

Role of terpenes from aphid-infested potato on searching and oviposition behavior of Episyrphus balteatus

To cope with pathogen and insect attacks, plants develop different mechanisms of defence, in both direct （physical and chemical） and indirect ways （attractive volatiles to entomophagous beneficials）. Plants are then able to express traits that facilitate ＂top-down＂ control of pests by attracting herbivore predators. Here we investigate the indirect defence mechanism of potato plants by analyzing the volatile patterns of both healthy and aphid- infested plants. Important changes in the emitted terpene pattern by the Myzus persicae infested host plant were observed. Using Solid Phase MicroExtraction （SPME） and GC-MS, the （E）-fl-farnesene （EBF） appeared to be emitted by aphid-infested potato and not by healthy plants. To assess the infochemical role of these volatile releases after aphid damage on the aphidophagous predators Episyrphus balteams, the hoverfly foraging behavior was assessed using the Observer 5.0 software （Noldus, Wageningen, The Netherlands）. Aphidfree potato plants were also used as a control volatile source in the predator behavioral study. While aphid-infested plants induced efficient searching and acceptation behaviors leading to egg-laying, no kairomonal effect of healthy potato plants was observed, leading to longer immobility durations and shorter searching periods in the net cage. High oviposition rate of E. balteatus was observed when aphid-infested potato was used （mean of 48.9 eggs per laying and per female）. On the other hand, no egg was produced by the hoverfly on healthy aphid-free plants. The E. balteatus foraging and reproductive behaviors according to the volatile emission from aphid-infested plants are discussed in relation to the potential use of active infochemical molecules in integrated aphid pest management.

Cytotoxic terpenes from Abies sibirica

One new and 16 known compounds were isolated from Abies sibirica. Their structures were assigned mainly on the basis of NMR and MS spectroscopic data. In bioassay for anti-proliferative activity against four human tumor cells, compound 7 exhibited selective anti-proliferative activity against COLO-205 tumor cell with an IC50 value of 0.9 μg/mL.

Synergistic Effects of CO_2 and LED Lighting on Accumulation of Terpenes in Roots of Gynura bicolor

Objective To investigate the essential oil profile and terpenes accumulation in the roots of Gynura bicolor （Asteracese） treated by CO2 and LED lighting. Methods G. bicolor herbs were treated by CO2 at the levels of 450 （control） and 1200 （elevated） μmol/mol and LED lighting with white light, RB20 （red/blue=8/2） and RB40 （red/blue=6/4）. Headspace solid-phase micro-extraction-GC MS was employed to analyze terpenes from the essential oil of the roots. Results In all treated-roots, the major components of terpenes were （E）-β-farnesene, α-, β-caryophyllene, α-, β-, γ-elemene, and α-pinene. Increasing CO2 significantly decreased mono- and sesqui-terpenes in the roots under all light conditions, leading to the decreasing yields of the essential oils. Terpenes were at a higher level in RB20-treated roots than that in RB40-treated ones under both control and elevated CO2. Conclusion CO2 （450 μmol/mol） and 20 % blue LED lights are more conducive to the accumulation of terpenes in the roots than 1200 μmol/mol CO2 and 40% blue LED lights.

Discovery and analysis of a new class of triterpenes derived from hexaprenyl pyrophosphate

Triterpenes are derived from squalene or oxidosqualene.However,a new class of triterpenes derived from hexaprenyl pyrophosphate has been recently discovered,formed by a new family of chimeric class I triterpene synthases.The cyclization mechanisms of triterpenes were elucidated by isotopic labeling and protein structural analyses,which helps understand the biosynthesis of triterpenes in nature.

Occurrence and biosynthesis of plant sesterterpenes (C25), a new addition to terpene diversity

Terpenes,the largest group of plant-specialized metabolites,have received considerable attention for their highly diverse biological activities.Monoterpenes(C10),sesquiterpenes(C15),diterpenes(C20),and triterpenes(C30)have been extensively investigated at both the biochemical and molecular levels over the past two decades.Sesterterpenes(C25),an understudied terpenoid group,were recently described by plant scientists at the molecular level.This review summarizes the plant species that produce sesterterpenes and describes recent developments in the field of sesterterpene biosynthesis,placing a special focus on the catalytic mechanism and evolution of geranylfarnesyl diphosphate synthase and sesterterpene synthase.Finally,we propose several questions to be addressed in future studies,which may help to elucidate sesterterpene metabolism in plants.

Cannabidiol and terpenes from hemp-ingredients for future foods and processing technologies

Hemp(Cannabis Sativa L.)is a broadly grown plant worldwide.In recent years,the cannabidiol(CBD)and terpene species in hemp have drawn increasing research interests due to their human health benefits and pharmaceutical values such as anti-anxiety,pain-relief,relaxation promotion,anti-inflammation and antimicrobial activities.However,the research and application of hemp CBD and terpenes in food systems are scarcely reported,because of various legal regulations,consumer basis and technological challenges.In addition,processing technologies of hemp such as drying,extraction and purifi cation for stable productions of high quality and food-safe CBD and terpene for food purposes have not been extensively studied,lacking thorough reviews.Therefore,in this comprehensive review,the basic characteristics of hemp CBD and terpenes,and their related legal regulations around the world are summarized;the status and technological challenges in the incorporation of hemp CBD and terpenes in food products,and in processing technologies of hemp biomass are identified and discussed;potential solutions,future trends,and research needs are highlighted.The fi ndings from this review may excite more food-related research on hemp processing and CBD/terpenes applications in foods.It can also help the hemp industry to improve the processing effi ciency of hemp as a valuable bioresource,and for food manufacturers to shape their paths to use hemp CBD and terpenes as future functional food ingredients.

Genome mining of fungal globin-like enzymes for catalyzing the synthesis of linear terpenes

Genome mining for the search and discovery of two new globin-like enzymes,TriB from Fusarium poae and TutaA from Schizophyllum commne,are involved in the synthesis of two linear terpenes tricinonoic acid(1)and 2-butenedioic acid(3).Both in vivo heterologous biosynthesis and in vitro biochemical assays showed that these two enzymes catalyzed the C-C double bond cleavage of a cyclic sesquiterpene precursor(-)-germacrene D(7)and a linear diterpene backbone schizostain(2),respectively.Our work presents an unusual formation mechanism of linear terpenes from fungi and expands the functional skills of globin-like enzymes in the synthesis of terpene compounds.

The chromosome-level genome of double-petal phenotype jasmine provides insights into the biosynthesis of floral scent

Jasmine(Jasminum sambac Aiton)is a well-known cultivated plant species for its fragrant flowers used in the perfume industry and cosmetics.However,the genetic basis of its floral scent is largely unknown.In this study,using PacBio,Illumina,10×Genomics and highthroughput chromosome conformation capture(Hi-C)sequencing technologies,a high-quality chromosome-level reference genome for J.sambac was obtained,exploiting a double-petal phenotype cultivar‘Shuangbanmoli’(JSSB).The results showed that the final assembled genome of JSSB is 580.33 Mb in size(contig N50=1.05 Mb;scaffold N50=45.07 Mb)with a total of 39618 predicted protein-coding genes.Our analyses revealed that the JSSB genome has undergone an ancient whole-genome duplication(WGD)event at 91.68 million years ago(Mya).It was estimated that J.sambac diverged from the lineage leading to Olea europaea and Osmanthus fragrans about 28.8 Mya.On the basis of a combination of genomic,transcriptomic and metabolomic analyses,a range of floral scent volatiles and genes were identified involved in the benzenoid/phenylpropanoid and terpenoid biosynthesis pathways.The results provide new insights into the molecular mechanism of its fragrance biosynthesis in jasmine.

Design,synthesis,and insecticidal activity of novel terpenoid ester compounds containing bicyclo[2.2.1]heptane against Aphis gossypii Glover

To discover novel and efficient compounds against Aphis gossypii Glover,a series of novel terpene ester derivatives containing the structure of bicyclo[2.2.1]heptane were designed and synthesized using tschimganin as the lead compound.Bioactivity assays showed that most tschimganin analogs exhibited moderate to outstanding insecticidal activity against A.gossypii.In particular,compound 56(LC_(50)=0.28μg mL^(-1)),identified as(1S,2S,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-yl nicotinate,exhibited the best activity,which was significantly superior to that of imidacloprid(LC_(50)=0.54μg mL^(-1))and sulfoxaflor(LC_(50)=0.70μg mL^(-1)).The precise and dependable 3D-QSAR model suggests a promising direction for further design of more active tschimganin-based insecticides.Metabolomics showed that compound 56 disrupted detoxification,amino acid biosynthesis,and energy metabolism and may affect the central nervous system of A.gossypii.The results of this study indicated that tschimganin analogs are a potential new class of green insecticides that can be used for the integrated management of A.gossypii.

Fractions of a chloroform extract of ajenjo leaves (Artemisiamendozana DC. var. mendozana) inhibit the proliferation,viability and clonogenicity of B16-F0 melanoma cells

The ajenjo,Artemisia mendozana DC.var.mendozana(Asteraceae),grows in the Andean foothills of Mendoza and San Juan,Argentina,and is used as a medicinal plant for its antispasmodic and antifungal properties.The aim of this work was to obtain fractions of a chloroform extract of ajenjo leaves and to evaluate the in vitro effects on proliferation,viability and clonogenicity of B16-F0 melanoma cells.Using a silica gel chromatography column,120 fractions were collected and grouped according to the chromatographic profile in 9 main fractions(F1–F9).Their major compounds identified were:terpenes(F1),terpenes and sesquiterpene lactones(F2–F3),sesquiterpenes(F4–F6)and phenols and sesquiterpenes(F7-9).B16-F0 cells were incubated for 72 h with DMSO(vehicle)or 0.1 mg/ml F1–F9.At 72 h of culture,F1 decreased both the growing index(GI)and cell viability.F2 and F3 both decreased GI and only F3 decreased clonogenic activity.F4 and F5 both decreased GI.Only F5 decreased cell viability and F4 decreased clonogenicity.Consequently,fractions F6–F8 did not affect any of the cell parameters assayed,while F9 decreased cell viability and inhibited clonogenicity.

The use of environmentally sustainable bio-derived solvents in solvent extraction applications——A review

Replacement of volatile organic compounds （VOCs） by greener or more environmentally sustainable solvents is becoming increasingly important due to the increasing health and environmental concerns as well as economic pressures associated with VOCs. Solvents that are derived from biomass, namely bio-derived solvents, are a type of green solvent that have attracted intensive investigations in recent years because of their advantages over con- ventional VOCs, such as low toxicity, biodegradability and renewability. This review aims to summarize the use of bio-derived solvents in solvent extraction applications, with special emphasis given to utilization of biodiesels and terpenes. Compared with the conventional VOCs, the overall performance of these bio-derived solvents is comparable in terms of extraction yields and selectivity for natural product extraction and no difference was found for metal extraction. To date most researchers have focused on laboratory scale thermodynamics studies. Future work is required to develop and test new bio-derived solvents and understand the kinetic performance as well as solvent extraction nilnt nlant studies.

High Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometric Analysis of Bilobalide and Ginkgolides in Ginkgo biloba L. Leaves

The ginkgo terpenoids including bilobalide and ginkgolides are the main pharmaceutical components in the leaves or extracts of Ginkgo biloba L. In this paper, the analysis of bilobalide and ginkgolides in leaves of Ginkgo biloba L. by high performance liquid chromatography (HPLC)-electrospray ionization (ESI)-mass spectrometry (MS) was carried out. The separation was performed on Inertsil ODS3 column with methanol-water (36:64) as mobile phase, with 1 mL·min -1 of flow rate at 35℃. Then the mass spectrum analysis was conducted by ZMD micromass electrospray ionization (ESI)-mass spectrometer (MS). The HPLC total ion chromatogram and selected ion chromatogram (with 325, 407, 423, 439 of m/z) of the sample and ESI-/MS mass spectra of the peaks in the chromatograms were obtained. So bilobalide, ginkgolide A, B, C and J in Ginkgo biloba L. leaves were identified. The method is easy and rapid, with a good accuracy.

Role of essential oils in food safety: Antimicrobial and antioxidant applications

Essential oils(EOs)are more complex and comprise a number of volatile and natural bioactive compounds,which often used in food industries as the best alternatives.This review focuses on the impact of EOs and the roles of their major components in food manufacturing as natural preservatives with the related mechanisms of action.In addition,the major bioactive molecules of different types of EOs and their pharmacological activities such as antioxidant,antifungal and antimicrobial effects on crop protection were also discussed.The major compounds of EOs represent potential antioxidant,antimicrobial and antifungal activities through various mechanisms.Different types of EOs such as tea tree oil,lemon oil,clove oil,cinnamon oil and thyme oil from various traditional plants,have significantly showed better antimicrobial and antioxidant activities,and also effectively increased the shelf lives of the cereal products and increased the quality of food safety.The major groups of EOs such as terpenes and aromatic volatile compounds,play a key role in food safety without affecting the quality.Due to their various activities including antioxidant and antimicrobial activities,EOs could be used as alternative preservatives to increase the shelf lives of cereals and crops.

Positive regulatory role of R2R3 MYBs in terpene biosynthesis in Lilium‘Siberia’

Terpenoids are the main components contributing to the fragrance of Lilium‘Siberia’,and LiTPS2 plays a critical role in the biosynthesis of monoterpenoids.Although the major terpene synthases in Lilium‘Siberia’have been identified,how these TPS genes are transcriptionally regulated remains elusive in this distinguished flower.This study aimed to identify transcription factors that regulate the terpene synthesis in Lilium,and disclose the related underlying transcriptional regulation mechanism.In this study,we identified three R2R3-MYB TFs—LiMYB1,LiMYB305 and LiMYB330,which were involved in regulating the biosynthesis of terpenes in Lilium‘Siberia’.Quantitative real-time PCR showed spatial and temporal expression patterns consistent with the emission patterns of terpene compounds.When LiMYB1,LiMYB305 and LiMYB330were overexpressed in flowers,the release of some main monoterpenes,such as linalool and ocimene,as well as the expression of TPS genes,especially for LiTPS2,were enhanced.A virus-induced gene silencing(VIGS)assay showed that silencing these three LiMYBs decreased the level of monoterpenes by down-regulating the expression of the TPS genes.The yeast one-hybrid and transient expression assays indicated that all three LiMYBs could bind to and activate the promoter of LiTPS2.Moreover,the yeast two-hybrid assay verified that LiMYB1 could interact with LiMYB308 and LiMYB330,indicating their synergistic roles in the regulation of floral terpene biosynthesis.In general,these results indicated that LiMYB1,LiMYB305,and LiMYB330 might play essential roles in terpene biosynthesis in Lilium and would provide a new perspective for the transcriptional regulation of volatile terpenes in flowers.

The chromosome-scale genome assembly of Jasminum sambac var. unifoliatum provides insights into the formation of floral fragrance

Jasmine [Jasminum sambac(L.) Ait.], a tropical and subtropical plant emits a sweet, heady fragrance during flower opening. However, the molecular mechanisms underlying this phenomenon remain largely unknown. In the present study, integrated Illumina sequencing, Pacbio sequencing, and high-throughput chromatin conformation capture(Hi-C) scaffolding was used to generate a 495.60 Mb genome assembly of J.sambac var. unifoliatum cultivar ‘Fuzhou Single-petal’(JSU-FSP), with contig N50 of 16.88 Mb;96.23% of the assembly was assigned to 13 pseudochromosomes. The genome harbors 30 989 protein-coding genes, and 49.47% of the assembled sequences are repetitive sequences. The analysis of duplication modes showed that 51% of genes were duplicated through dispersed duplication, and expanded gene families are mainly involved in photosynthesis, which may be responsible for the light-loving characteristic specific to jasmine. Transcriptome analysis revealed that at least 35 structural genes involved in the biosynthesis of volatile terpenes(VTs), volatile phenylpropanoid/benzenoids(VPBs),fatty acid-derived volatiles(FADVs), and indole were highly expressed in the flower-opening stage, both preharvest and postharvest, and are proposed to be important in endowing flower aroma. Additionally, at least 28 heat shock protein(HSP) and 11 β-glucosidase(BGLU) genes may be involved in the formation of floral fragrance. These findings provide insights into the formation of the floral fragrance of jasmine and will promote germplasm utilization for breeding improved jasmine varieties.

Effects of combined cannabidiol(CBD)and hops(Humulus lupulus)terpene extract treatment on RAW 264.7 macrophage viability and inflammatory markers

This study investigates the potential of cannabidiol(CBD),one major cannabinoid of the plant Cannabis sativa,alone and in combination with a terpene-enriched extract from Humulus lupulus(“Hops 1”),on the LPS-response of RAW 264.7 macrophages as an established in vitro model of inflammation.With the present study,we could support earlier findings of the anti-inflammatory potential of CBD,which showed a dose-dependent[0-5μM]reduction in nitric oxide and tumor necrosis factor-alpha(TNF-α)released by LPS-stimulated RAW 264.7 macrophages.Moreover,we observed an additive anti-inflammatory effect after combined CBD[5μM]and hops extract[40μg/mL]treatment.The combination of CBD and Hops 1 showed effects in LPS-stimulated RAW 264.7 cells superior to the single sub-stance treatments and akin to the control hydrocortisone.Furthermore,cellular CBD uptake increased dose-depend-ently in the presence of terpenes from Hops 1 extract.The anti-inflammatory effect of CBD and its cellular uptake positively correlated with terpene concentration,as indicated by comparison with a hemp extract containing both CBD and terpenes.These findings may contribute to the postulations for the so-called“entourage effect”between cannabinoids and terpenes and support the potential of CBD combined with phytomolecules from a non-cannabi-noid source,such as hops,for the treatment of inflammatory diseases.