Identification and characterization of two sesquiterpene synthase genes involved in volatile-mediated defense in tea plant (Camellia sinensis)

Trichomes and unique gene expression confer insect herbivory resistance in Vitis labrusca grapevines

BACKGROUND

Grapevine (Vitis) is one of the world's most valuable fruit crops, but insect herbivory can decrease yields. Understanding insect herbivory resistance is critical to mitigating these losses. Vitis labrusca, a wild North American grapevine species, has been leveraged in breeding programs to generate hybrid grapevines with enhanced abiotic and biotic stress resistance, rendering it a valuable genetic resource for sustainable viticulture. This study assessed the resistance of V. labrusca acc. 'GREM4' and Vitis vinifera cv. 'PN40024' grapevines to Popillia japonica (Japanese beetle) herbivory and identified morphological and genetic adaptations underlying this putative resistance.

RESULTS

'GREM4' displayed greater resistance to beetle herbivory compared to 'PN40024' in both choice and no-choice herbivory assays spanning periods of 30 min to 19 h. 'GREM4' had significantly higher average leaf trichome densities than 'PN40024' and beetles preferred to feed on the side of leaves with fewer trichomes. When leaves from each species that specifically did not differ in trichome densities were fed on by beetles, significantly less leaf area was damaged in 'GREM4' (3.29mm2) compared to 'PN40024' (9.80mm2), suggesting additional factors beyond trichomes contributed to insect herbivory resistance in 'GREM4'. Comparative transcriptomic analyses revealed 'GREM4' exhibited greater constitutive (0 h) expression of defense response and secondary metabolite biosynthesis genes compared to 'PN40024', indicative of heightened constitutive defenses. Upon herbivory, 'GREM4' displayed a greater number of differentially expressed genes (690) compared to 'PN40024' (502), suggesting a broader response. Genes up-regulated in 'GREM4' were enriched in terpene biosynthesis, flavonoid biosynthesis, phytohormone signaling, and disease defense-related functions, likely contributing to heighted insect herbivory defense, while genes differentially expressed in 'PN40024' under herbivory were enriched in xyloglucan, cell wall formation, and calcium ion binding. The majority of genes implicated in insect herbivory defense were orthologs with specific expression patterns in 'GREM4' and 'PN40024', but some paralogous and genome-specific genes also likely contributed to conferring resistance.

CONCLUSIONS

Our findings suggest that 'GREM4' insect herbivory resistance was attributed to a combination of factors, including trichomes and unique constitutive and inducible expression of genes implicated in terpene, flavonoid, and phenylpropanoid biosynthesis, as well as pathogen defense.

Variation in the Floral Scent Chemistry of Nymphaea 'Eldorado', a Valuable Water Lily, with Different Flowering Stages and Flower Parts

Nymphaea 'Eldorado', a valuable water lily, is a well-known fragrant plant in China. Studying the temporal and spatial characteristics of the floral components of this plant can provide a reference for the further development and utilization of water lily germplasm resources. In this study, headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) was used to explore the types and relative contents of floral components at different flowering stages (S1: bud stage; S2: initial-flowering stage; S3: full-flowering stage; S4: end-flowering stage) and in different floral organs of N. 'Elidorado', combined with the observation of the microscopic structure of petals. A total of 60 volatile organic compounds (VOCs) were detected at different flowering stages, and there were significant differences in floral VOCs at different flowering stages and in different flower organs. The volatile compounds of N. 'Eldorado' can be divided into seven chemical classes,, namely, alkenes, alcohols, esters, aldehydes, ketones, alkanes, and others; the most common were alkenes and alkanes. A total of 39, 44, 47, and 42 volatile compounds were detected at S1, S2, S3, and S4. The VOCs present in high concentrations include benzaldehyde, benzyl alcohol, benzyl acetate, trans-α-bergamotene, α-curcumene, cis-α-farnesene, and so on. The types and total contents of volatiles at the full-flowering stage were higher than at other flowering stages. Comparing the VOCs in different parts of flower organs, it was found that the contents of alcohols, esters, and aldehydes were greatest in the petals, the alkenes in stamens were abundant with a relative content of up to 54.93%, and alkanes in the pistil were higher than in other parts. The types and total contents of volatiles in the stamens of N. 'Eldorado' were higher than those in other flower organs; they were the main part releasing fragrance. The observation of petal microstructure revealed that the size and quantity of the papillae on the epidermises of petals, the number of intracellular plastids, and the aggregates of floral components (osmophilic matrix granules) were significantly higher at the full-flowering stage than at the other flowering stages. This study suggested the main flowering stage and location at which the floral VOCs are released by N. 'Eldorado' and provided a reference for guiding the breeding of this water lily, exploring genetic patterns and developing related products.

Plant-derived monoterpene S-linalool and β-ocimene generated by CsLIS and CsOCS-SCZ are key chemical cues for attracting parasitoid wasps for suppressing Ectropis obliqua infestation in Camellia sinensis L

Insect-induced plant volatile organic compounds (VOCs) may function as either direct defence molecules to deter insects or indirect defence signals to attract the natural enemies of the invading insects. Tea (Camellia sinensis L.), an important leaf-based beverage crop, is mainly infested by Ectropis obliqua which causes the most serious damage. Here, we report a mechanistic investigation of tea plant-derived VOCs in an indirect defence mechanism against E. obliqua. Parasitoid wasp Parapanteles hyposidrae, a natural enemy of E. obliqua, showed strong electrophysiological response and selection behaviour towards S-linalool and β-ocimene, two monoterpenes with elevated emission from E. obliqua-damaged tea plants. Larvae frass of E. obliqua, which also released S-linalool and β-ocimene, was found to attract both mated female or male Pa. hyposidrae according to gas chromatography-electroantennogram detection and Y-tube olfactometer assays. In a field setting, both S-linalool and β-ocimene were effective in recruiting both female and male Pa. hyposidrae wasps. To understand the molecular mechanism of monoterpenes-mediated indirect defence in tea plants, two novel monoterpene synthase genes, CsLIS and CsOCS-SCZ, involved in the biosynthesis of S-linalool or β-ocimene, respectively, were identified and biochemically characterised. When the expression of these two genes in tea plants was inhibited by antisense oligodeoxynucleotide, both volatile emission and attraction of wasps were reduced. Furthermore, gene expression analysis suggested that the expression of CsLIS and CsOCS-SCZ is regulated by the jasmonic acid signalling pathway in the tea plant.

Terpene Synthase Gene Family in Chinese Chestnut (Castanea mollissima BL.) Harbors Two Sesquiterpene Synthase Genes Implicated in Defense against Gall Wasp Dryocosmus kuriphilus

Chinese chestnut (Castanea mollissima BL.) is a well-known fruit tree that has been cultivated in East Asia for millennia. Leaves and buds of the plant can become seriously infested by the gall wasp Dryocosmus kuriphilus (GWDK), which results in gall formation and associated significant losses in fruit production. Herbivore-induced terpenes have been reported to play an important role in plant-herbivory interactions, and in this study, we show that upon herbivory by GWDK, four terpene-related compounds were significantly induced, while the concentrations of these four compounds in intact buds were relatively low. Among these compounds, (E)-nerolidol and (E, E)-α-farnesene have frequently been reported to be involved in plant herbivory defenses, which suggests direct and/or indirect functions in chestnut GWDK defenses. Candidate terpene synthase (TPS) genes that may account for (E)-nerolidol and (E, E)-α-farnesene terpene biosynthesis were characterized by transcriptomics and phylogenetic approaches, which revealed altered transcript levels for two TPSs: CmAFS, a TPS-g subfamily member, and CmNES/AFS, a TPS-b clade member. Both genes were dramatically upregulated in gene expression upon GWDK infestation. Furthermore, Agrobacterium tumefaciens-mediated transient overexpression in Nicotiana benthamiana showed that CmAFS catalyzed the formation of (E, E)-α-farnesene, while CmNES/AFS showed dual (E)-nerolidol and (E, E)-α-farnesene synthase activity. Biochemical assays of the recombinant CmAFS and CmNES/AFS proteins confirmed their catalytic activity in vitro, and the enzymatic products were consistent with two of the major volatile compounds released upon GWDK-infested chestnut buds. Subcellular localization demonstrated that CmAFS and CmNES/AFS were both localized in the cytoplasm, the primary compartment for sesquiterpene synthesis. In summary, we show that two novel sesquiterpene synthase genes CmAFS and CmNES/AFS are inducible by herbivory and can account for the elevated accumulation of (E, E)-α-farnesene and (E)-nerolidol upon GWDK infestation and may be implicated in chestnut defense against GWDK herbivores.

Transcriptomic Insights into the Enhanced Aroma of Guangdong Oolong Dry Tea (Camellia sinensis cv. Yashixiang Dancong) in Winter

Winter dry tea (WDT) exhibits a more intense and lasting aroma compared to dry tea from other seasons; however, this conclusion is solely based on sensory outcomes and lacks corroborative theoretical evidence. Our study aimed to analyze the aroma compounds in WDT and investigate the causes behind the formation of WDT's aroma by analyzing the volatile organic compounds (VOCs) in WDT, spring dry tea (SDT), winter fresh leaves (WFLs) and spring fresh leaves (SFLs) by gas chromatography-mass spectrometry (GC-MS), complemented by an analysis of gene expression pertinent to WFLs and SFLs by using transcriptomic analysis. The results revealed a significant increase in total VOCs in WDT compared to SDT, with WDT exhibiting distinct woody aromas as indicated by a higher α-muurolene content. In WFL, the contents of aldehydes and ketones were richer than those in SFL. Notably, the study found that UDP-glycosyltransferase genes in WFLs were significantly up-regulated, potentially promoting the synthesis of terpene glycosides. These terpene glycosides can release terpene aroma compounds during processing, contributing significantly to the intense and lasting aroma of WDT. Overall, this research provides valuable insights into the mechanism behind aroma formation in Guangdong oolong tea harvested during winter.

Diverse O-methyltransferases catalyze the biosynthesis of floral benzenoids that repel aphids from the flowers of waterlily Nymphaea prolifera

Nymphaea is a key genus of the ANA grade (Amborellales, Nymphaeales, and Austrobaileyales) of basal flowering plants, which serve as a key model to study the early evolution of floral traits. In this study, we comprehensively investigated the emission, biosynthesis, and biological function of the floral scent in a night-blossoming waterlily Nymphaea prolifera. The headspace volatile collection combined with GC-MS analysis showed that the floral scent of N. prolifera is predominately comprised by methylated benzenoids including anisole, veratrole, guaiacol, and methoxyanisole. Moreover, the emission of these floral benzenoids in N. prolifera exhibited temporal and spatial pattern with circadian rhythm and tissue specificity. By creating and mining transcriptomes of N. prolifera flowers, 12 oxygen methyltransferases (NpOMTs) were functionally identified. By in vitro enzymatic assay, NpOMT3, 6, and 7 could produce anisole and NpOMT5, 7, 9, produce guaiacol, whereas NpOMT3, 6, 9, 11 catalyzed the formation of veratrole. Methoxyanisole was identified as the universal product of all NpOMTs. Expression patterns of NpOMTs provided implication for their roles in the production of the respective benzenoids. Phylogenetic analysis of OMTs suggested a Nymphaea-specific expansion of the OMT family, indicating the evolution of lineage-specific functions. In bioassays, anisole, veratrole, and guaiacol in the floral benzenoids were revealed to play the critical role in repelling waterlily aphids. Overall, this study indicates that the basal flowering plant N. prolifera has evolved a diversity and complexity of OMT genes for the biosynthesis of methylated benzenoids that can repel insects from feeding the flowers. These findings provide new insights into the evolutional mechanism and ecological significance of the floral scent from early-diverged flowering plants.

Volatile compound-mediated plant-plant interactions under stress with the tea plant as a model

Plants respond to environmental stimuli via the release of volatile organic compounds (VOCs), and neighboring plants constantly monitor and respond to these VOCs with great sensitivity and discrimination. This sensing can trigger increased plant fitness and reduce future plant damage through the priming of their own defenses. The defense mechanism in neighboring plants can either be induced by activation of the regulatory or transcriptional machinery, or it can be delayed by the absorption and storage of VOCs for the generation of an appropriate response later. Despite much research, many key questions remain on the role of VOCs in interplant communication and plant fitness. Here we review recent research on the VOCs induced by biotic (i.e. insects and pathogens) and abiotic (i.e. cold, drought, and salt) stresses, and elucidate the biosynthesis of stress-induced VOCs in tea plants. Our focus is on the role of stress-induced VOCs in complex ecological environments. Particularly, the roles of VOCs under abiotic stress are highlighted. Finally, we discuss pertinent questions and future research directions for advancing our understanding of plant interactions via VOCs.

Cloning of the promoter of rice brown planthopper feeding-inducible gene OsTPS31 and identification of related cis-regulatory elements

BACKGROUND

Brown planthopper (BPH; Nilaparvata lugens) is one of the most serious pests of rice in the world. Insect-resistant genetic engineering is a very effective technology to control BPH. The promoters and cis-regulatory elements inducible by plant-feeding insects are critical for genetic engineering of insect-resistant crops.

RESULTS

In this study, we cloned a promoter Ptps31 and a 7 bp cis-regulatory sequence that up-regulated downstream genes induced by BPH feeding. The promoter of OsTPS31 (Ptps31) unresponsive to physical damage but responsive to BPH feeding was cloned and functionally verified. The results showed that expression of the OsBPH14 gene driven by the promoter region from -510 to -246 bp in rice could significantly improve the resistance to BPH. The promoter region from -376 to -370 bp (TAGTGTC) was identified as a cis-regulatory sequence related to BPH feeding induction of downstream gene expression.

CONCLUSION

The findings provide a new promoter and a new cis-regulatory sequence tool for the research on and application of rice BPH resistance genes, as well as a new perspective for functional analysis of the OsTPS31 gene. © 2023 Society of Chemical Industry.

Characterization of Aroma Active Compound Production during Kombucha Fermentation: Towards the Control of Sensory Profiles

Since the sensorial profile is the cornerstone for the development of kombucha as a beverage with mass market appeal, advanced analytical tools are needed to gain a better understanding of the kinetics of aromatic compounds during the fermentation process to control the sensory profiles of the drink. The kinetics of volatile organic compounds (VOCs) was determined using stir bar sorptive extraction-gas chromatography-mass spectrometry, and odor-active compounds were considered to estimate consumer perception. A total of 87 VOCs were detected in kombucha during the fermentation stages. The synthesis of mainly phenethyl alcohol and isoamyl alcohol probably by Saccharomyces genus led to ester formation. Moreover, the terpene synthesis occurring at the beginning of fermentation (Δ-3-carene, α-phellandrene, γ-terpinene, m- and p-cymene) could be related to yeast activity as well. Principal component analysis identified classes that allowed the major variability explanation, which are carboxylic acids, alcohols, and terpenes. The aromatic analysis accounted for 17 aroma-active compounds. These changes in the evolution of VOCs led to flavor variations: from citrus-floral-sweet notes (geraniol and linalool domination), and fermentation brought intense citrus-herbal-lavender-bergamot notes (α-farnesene). Finally, sweet-floral-bready-honey notes dominated the kombucha flavor (2-phenylethanol). As this study allowed to estimate kombucha sensory profiles, an insight for the development of new drinks by controlling the fermentation process was suggested. Such a methodology should allow a better control and optimization of their sensory profile, which could in turn lead to greater consumer acceptance.

Identification of QTL controlling volatile terpene contents in tea plant (Camellia sinensis) using a high-aroma 'Huangdan' x 'Jinxuan' F1 population

Aroma is an important factor affecting the character and quality of tea. The improvement of aroma trait is a crucial research direction of tea plant breeding. Volatile terpenes, as the major contributors to the floral odors of tea products, also play critical roles in the defense responses of plants to multiple stresses. However, previous studies have largely focused on the aroma formation during the manufacture of tea or the comparison of raw tea samples. The mechanisms causing different aroma profiles between tea cultivars have remained underexplored. In the current study, a high-density genetic linkage map of tea plant was constructed based on an F₁ population of 'Huangdan' × 'Jinxuan' using genotyping by sequencing. This linkage map covered 1754.57 cM and contained 15 linkage groups with a low inter-marker distance of 0.47 cM. A total of 42 QTLs associated with eight monoterpene contents and 12 QTLs associated with four sesquiterpenes contents were identified with the average PVE of 12.6% and 11.7% respectively. Furthermore, six candidate genes related to volatile terpene contents were found in QTL cluster on chromosome 5 by RNA-seq analysis. This work will enrich our understanding of the molecular mechanism of volatile terpene biosynthesis and provide a theoretical basis for tea plant breeding programs for aroma quality improvement.

Histone deacetylase CsHDA6 mediates the regulated formation of the anti-insect metabolite α-farnesene in tea (Camellia sinensis)

α-Farnesene accumulated in tea plants following infestations by most insects, and mechanical wounding is the common factor. However, the specific mechanism underlying the wounding-regulated accumulation of α-farnesene in tea plants remains unclear. In this study, we observed that histone deacetylase inhibitor treatment induced the accumulation of α-farnesene. The histone deacetylase CsHDA6 interacted directly with CsMYC2, which was an important transcription factor in the jasmonic acid (JA) pathway, and co-regulated the expression of the key α-farnesene synthesis gene CsAFS. Wounding caused by insect infestation affected CsHDA6 production at the transcript and protein levels, while also inhibited the binding of CsHDA6 to the CsAFS promoter. The resulting increased acetylation of histones H3/H4 in CsAFS enhanced the expression of CsAFS and the accumulation of α-farnesene. In conclusion, our study demonstrated the effect of histone acetylation on the production of tea plant HIPVs and revealed the importance of the CsHDA6-CsMYC2 transcriptional regulatory module.

Allele-specific expression and chromatin accessibility contribute to heterosis in tea plants (Camellia sinensis)

Heterosis is extensively used to improve crop productivity, yet its allelic and chromatin regulation remains unclear. Based on our resolved genomes of the maternal TGY and paternal HD, we analyzed the contribution of allele-specific expression (ASE) and chromatin accessibility of JGY and HGY, the artificial hybrids of oolong tea with the largest cultivated area in China. The ASE genes (ASEGs) of tea hybrids with maternal-biased were mainly related to the energy and terpenoid metabolism pathways, whereas the ASEGs with paternal-biased tend to be enriched in glutathione metabolism, and these parental bias of hybrids may coordinate and lead to the acquisition of heterosis in more biological pathways. ATAC-seq results showed that hybrids have significantly higher accessible chromatin regions (ACRs) compared with their parents, which may confer broader and stronger transcriptional activity of genes in hybrids. The number of ACRs with significantly increased accessibility in hybrids was much greater than decreased, and the associated alleles were also affected by differential ACRs across different parents, suggesting enhanced positive chromatin regulation and potential genetic effects in hybrids. Core ASEGs of terpene and purine alkaloid metabolism pathways with significant positive heterosis have greater chromatin accessibility in hybrids, and were potentially regulated by several members of the MYB, DOF and TRB families. The binding motif of CsMYB85 in the promoter ACR of the rate-limiting enzyme CsDXS was verified by DAP-seq. These results suggest that higher numbers and more accessible ACRs in hybrids contribute to the regulation of ASEGs, thereby affecting the formation of heterotic metabolites.

A monoterpene synthase gene cluster of tea plant (Camellia sinensis) potentially involved in constitutive and herbivore-induced terpene formation

Monoterpenes and sesquiterpenes are the most abundant volatiles in tea plants and have dual functions in aroma quality formation and defense responses in tea plants. Terpene synthases (TPS) are the key enzymes for the synthesis of terpenes in plants; however, the functions of most of them in tea plants are still unknown. In this study, six putative terpene biosynthesis gene clusters were identified from the tea plant genome. Then we cloned three new TPS-b subfamily genes, CsTPS08, CsTPS10 and CsTPS58. In vitro enzyme assays showed that CsTPS08 and CsTPS58 are two multiple-product terpene synthases, with the former synthesizing linalool as the main product, and β-myrcene, α-phellandrene, α-terpinolene, D-limonene, cis-β-ocimene, trans-β-ocimene and (4E,6Z)-allo-ocimene as minor products are also detected, while the latter catalyzing the formation of α-pinene and D-limonene using GPP as the substrate. No product of CsTPS10 was detected in the prokaryotic expression system, but geraniol production was detected when transiently expressed in tobacco leaves. CsTPS08 and CsTPS10 are two functional members of a monoterpene synthase gene cluster, which were significantly induced during both Ectropis oblique feeding and fresh leaf spreading treatments, suggesting that they have dual functions involved in tea plant pest defense and tea aroma quality regulation. In addition, the differences in their expression levels in different tea plant cultivars provide a possibility for the subsequent screening of tea plant resources with a specific aroma flavor. Our results deepen the understanding of terpenoid synthesis in tea plants.

Population-specific, recent positive selection signatures in cultivated Cucumis sativus L. (cucumber)

Population-specific, positive selection promotes the diversity of populations and drives local adaptations in the population. However, little is known about population-specific, recent positive selection in the populations of cultivated cucumber (Cucumis sativus L.). Based on a genomic variation map of individuals worldwide, we implemented a Fisher’s combination method by combining 4 haplotype-based approaches: integrated haplotype score (iHS), number of segregating sites by length (nSL), cross-population extended haplotype homozygosity (XP-EHH), and Rsb. Overall, we detected 331, 2,147, and 3,772 population-specific, recent positive selective sites in the East Asian, Eurasian, and Xishuangbanna populations, respectively. Moreover, we found that these sites were related to processes for reproduction, response to abiotic and biotic stress, and regulation of developmental processes, indicating adaptations to their microenvironments. Meanwhile, the selective genes associated with traits of fruits were also observed, such as the gene related to the shorter fruit length in the Eurasian population and the gene controlling flesh thickness in the Xishuangbanna population. In addition, we noticed that soft sweeps were common in the East Asian and Xishuangbanna populations. Genes involved in hard or soft sweeps were related to developmental regulation and abiotic and biotic stress resistance. Our study offers a comprehensive candidate dataset of population-specific, selective signatures in cultivated cucumber populations. Our methods provide guidance for the analysis of population-specific, positive selection. These findings will help explore the biological mechanisms of adaptation and domestication of cucumber.

Functional Characterization of a New Bifunctional Terpene Synthase LpNES1 from a Medicinal Plant Laggera pter odonta

Laggera pterodonta, known in China as 'Choulingdan' for its stimulous odor, has long been used as traditional herbal medicine. The essential oil of L. pterodonta, which exhibits various pharmacological activities, is a rich resource of monoterpenes and sesquiterpenes. To date, however, the terpene synthases responsible for their production remain unknown. In present study, a new terpene synthase gene (LpNES1) was identified from L. pterodonta, transcript level of which was significantly upregulated in response to methyl jasmonate treatment. Recombinant LpNES1 could synthesize (E)-nerolidol and minor β-farnesene from farnesyl diphosphate and linalool from geranyl diphosphate in vitro. Whereas, only sesquiterpenes including (E)-nerolidol and minor β-farnesene were released when LpNES1 was reconstituted in yeast, even coexpressed with a geranyl diphosphate synthase (ERG20^WW). Combined with subcellular localization experiment, the result indicated that the cytosol-targeted LpNES1 was responsible for (E)-nerolidol biosynthesis exclusively in L. pterodonta. Additionally, the expression level of LpNES1 gene was more prominent in floral buds than that in other tissues. LpNES1 characterized in present study not only lays the molecular foundation for sesquiterpene biosynthesis of L. pterodonta, but provides a key element for further biosynthesis of bioactive compound in microbes.

Taxonomic Insights and Its Type Cyclization Correlation of Volatile Sesquiterpenes in Vitex Species and Potential Source Insecticidal Compounds: A Review

Sesquiterpenes (SS) are secondary metabolites formed by the bonding of 3 isoprene (C5) units. They play an important role in the defense and signaling of plants to adapt to the environment, face stress, and communicate with the outside world, and their evolutionary history is closely related to their physiological functions. This review considers their presence and extensively summarizes the 156 sesquiterpenes identified in Vitextaxa, emphasizing those with higher concentrations and frequency among species and correlating with the insecticidal activities and defensive responses reported in the literature. In addition, we classify the SS based on their chemical structures and addresses cyclization in biosynthetic origin. Most relevant sesquiterpenes of the Vitex genus are derived from the germacredienyl cation mainly via bicyclogermacrene and germacrene C, giving rise to aromadrendanes, a skeleton with the highest number of representative compounds in this genus, and 6,9-guaiadiene, respectively, indicating the production of 1.10-cyclizing sesquiterpene synthases. These enzymes can play an important role in the chemosystematics of the genus from their corresponding routes and cyclizations, constituting a new approach to chemotaxonomy. In conclusion, this review is a compilation of detailed information on the profile of sesquiterpene in the Vitex genus and, thus, points to new unexplored horizons for future research.

Therapeutic Applications of Terpenes on Inflammatory Diseases

In the last decades, the search for natural products with biological applications as alternative treatments for several inflammatory diseases has increased. In this respect, terpenes are a family of organic compounds obtained mainly from plants and trees, such as tea, cannabis, thyme, and citrus fruits like lemon or mandarin. These molecules present attractive biological properties such as analgesic and anticonvulsant activities. Furthermore, several studies have demonstrated that certain terpenes could reduce inflammation symptoms by decreasing the release of pro-inflammatory cytokines for example, the nuclear transcription factor-kappa B, interleukin 1, and the tumor necrosis factor-alpha. Thus, due to various anti-inflammatory drugs provoking side effects, the search and analysis of novel therapeutics treatments are attractive. In this review, the analysis of terpenes' chemical structure and their mechanisms in anti-inflammatory functions are addressed. Additionally, we present a general analysis of recent investigations about their applications as an alternative treatment for inflammatory diseases. Furthermore, we focus on terpenes-based nanoformulations and employed dosages to offer a global perspective of the state-of-the-art.