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Chemoprevention is referred to as a strategy to inhibit, suppress, or reverse tumor development and progression in healthy people along with high-risk subjects and oncologic patients through using pharmacological or natural substances. Numerous phytochemicals have been widely described in the literature to possess chemopreventive properties, although their clinical usefulness remains to be defined. Among them, caryophyllane sesquiterpenes are natural compounds widely occurring in nature kingdoms, especially in plants, fungi, and marine environments. Several structures, characterized by a common caryophyllane skeleton with further rearrangements, have been identified, but those isolated from plant essential oils, including β-caryophyllene, β-caryophyllene oxide, α-humulene, and isocaryophyllene, have attracted the greatest pharmacological attention. Emerging evidence has outlined a complex polypharmacological profile of caryophyllane sesquiterpenes characterized by blocking, suppressing, chemosensitizing, and cytoprotective properties, which suggests a possible usefulness of these natural substances in cancer chemoprevention for both preventive and adjuvant purposes. In the present review, the scientific knowledge about the chemopreventive properties of caryophyllane sesquiterpenes and the mechanisms involved have been collected and discussed; moreover, possible structure–activity relationships have been highlighted. Although further high-quality studies are required, the promising preclinical findings and the safe pharmacological profile encourage further studies to define a clinical usefulness of caryophyllane sesquiterpenes in primary, secondary, or tertiary chemoprevention.

The Asian Citrus Psyllid (ACP), Diaphorina citri , severely threatens citrus production worldwide by transmitting the greening (= Huanglongbing)—causing bacterium Candidatus Liberibacter asiaticus. There is growing evidence that the push-pull strategy is suitable to partially mitigate HLB by repelling ACP with transgenic plants engineered to produce repellents and attracting the vector to plants with a minimal disease transmission rate. Species that pull ACP away from commercial citrus plants have been identified, and transgenic plants that repel ACP have been developed. The concept of a repellent-producing plant was first demonstrated with an Arabidopsis line engineered to overexpress a gene controlling the synthesis of β -caryophyllene and other sesquiterpenes. We have analyzed the volatile organic compounds released by this Arabidopsis line and identified α -humulene, α -copaene, and trace amounts of β -elemene, in addition to β -caryophyllene. Behavioral measurements demonstrated that α -copaene repels ACP at doses ca. 100× lower than those needed for β -caryophyllene repellence. In contrast, α -humulene is innocuous at the level emitted by the transgenic plant. We confirmed that a mixture of the three sesquiterpenes in the ratio 1:100:10 repels ACP. Likewise, a commercial sample of copaiba oil containing the three sesquiterpenes, in a proportion similar to that in the transgenic plant, repelled ACP.

Zerumbone is a pharmacologically active sesquiterpenoid with limited availability. This study aims to elucidate its biosynthetic pathway in by identifying and characterizing the key enzymes responsible for its production. Candidate genes were selected via transcriptome analysis and phylogenetics. CwTPS8 and CwSDR1 were cloned and functionally characterized using in vitro enzyme assays and heterologous expression in engineered . Molecular docking and site-directed mutagenesis were applied to investigate the catalytic mechanism of CwTPS8. CwTPS8 was identified as a multifunctional sesquiterpene synthase that catalyzes the formation of α-humulene (a key zerumbone precursor) and β-caryophyllene as main products, along with several minor sesquiterpenes. Mutagenesis studies identified critical residues (e.g., Thr437, Cys436) that significantly shift product specificity toward α-humulene. CwSDR1 was characterized as a short-chain dehydrogenase that efficiently oxidizes 8-hydroxy-α-humulene to zerumbone. A de novo biosynthetic pathway was reconstructed in yeast, resulting in zerumbone production at 0.50 μg/L. This study expands the genetic toolkit for zerumbone biosynthesis and provides insights into enzyme engineering and metabolic engineering strategies to enhance production. Limitations in precursor supply and catalytic efficiency highlight areas for future optimization.

While acute inflammation is an essential physical response to harmful external influences, the transition to chronic inflammation is problematic and associated with the development and worsening of many deadly diseases. Until now, established pharmaceutical agents have had many side effects when used for long periods. In this study, a possible anti-inflammatory effect of the sesquiterpene α-humulene on lipopolysaccharide (LPS) induction was tested. Herein, human THP-1-derived macrophages were used and their pro-inflammatory interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and interleukin-1β (IL-1β) cytokine release was measured by means of enzyme-linked immunosorbent assay. A dose-dependent effect of α-humulene on IL-6 release was observed at 0.5 and 100 µM α-humulene, with a maximum IL-6 inhibition of 60% compared to the LPS reference value after the addition of 100 µM α-humulene. TNF-α as well as IL-1β cytokine concentrations were not reduced by the addition of 0.5 and 100 µM α-humulene. This study suggests that α-humulene has potential as a promising natural alternative to established pharmaceuticals for the treatment of elevated IL-6 levels and chronic inflammation in humans.

Limited evidence has suggested that terpenes found in Cannabis sativa are analgesic, and could produce an “entourage effect” whereby they modulate cannabinoids to result in improved outcomes. However this hypothesis is controversial, with limited evidence. We thus investigated Cannabis sativa terpenes alone and with the cannabinoid agonist WIN55,212 using in vitro and in vivo approaches. We found that the terpenes α-humulene, geraniol, linalool, and β-pinene produced cannabinoid tetrad behaviors in mice, suggesting cannabimimetic activity. Some behaviors could be blocked by cannabinoid or adenosine receptor antagonists, suggesting a mixed mechanism of action. These behavioral effects were selectively additive with WIN55,212, suggesting terpenes can boost cannabinoid activity. In vitro experiments showed that all terpenes activated the CB1R, while some activated other targets. Our findings suggest that these Cannabis terpenes are multifunctional cannabimimetic ligands that provide conceptual support for the entourage effect hypothesis and could be used to enhance the therapeutic properties of cannabinoids.

Background: The detection of environmental cues and signals via the sensory system directs behavioral choices in diverse organisms. Insect larvae rely on input from the chemosensory system, mainly olfaction, for locating food sources. In several lepidopteran species, foraging behavior and food preferences change across larval instars; however, the molecular mechanisms underlying such behavioral plasticity during larval development are not fully understood. Here, we hypothesize that expression patterns of odorant receptors (ORs) change during development, as a possible mechanism influencing instar-specific olfactory-guided behavior and food preferences. Results: We investigated the expression patterns of ORs in larvae of the cotton leafworm Spodoptera littoralis between the first and fourth instar and revealed that some of the ORs show instar-specific expression. We functionally characterized one OR expressed in the first instar, SlitOR40, as responding to the plant volatile, βcaryophyllene and its isomer α-humulene. In agreement with the proposed hypothesis, we showed that first but not fourth instar larvae responded behaviorally to β-caryophyllene and α-humulene. Moreover, knocking out this odorant receptor via CRISPR-Cas9, we confirmed that instar-specific responses towards its cognate ligands rely on the expression of SlitOR40. Conclusion: Our results provide evidence that larvae of S. littoralis change their peripheral olfactory system during development. Furthermore, our data demonstrate an unprecedented instar-specific behavioral plasticity mediated by an OR, and knocking out this OR disrupts larval behavioral plasticity. The ecological relevance of such behavioral plasticity for S. littoralis remains to be elucidated, but our results demonstrate an olfactory mechanism underlying this plasticity in foraging behavior during larval development.

This study aims to experimentally and theoretically examine the plant Aethionema sancakense, which was determined as a new species and whose essential oil and fatty acid compositions were characterized by GC/GC-MS technique. Linoleic acid (23.1%), α-humulene (19.8%), camphene (13.9%), and heptanal (9.7%) were found to be the major essential oil components of A. sancakense aerial part structures. The quantum chemical calculations of these four molecules that are very important to this plant were performed using the density functional method (DFT)/B3LYP with the 6-31 G (d, p) basis set in the ground state for the gas phase. The molecular structures, HOMO-LUMO energies, electronic properties, Fukui functions, and molecular electrostatic potential (MEP) surfaces of the major constituents of Aethionema sancakense essential oil were calculated and interpreted. Finally, the RDG-NCI analysis of these molecules was performed to determine the non-covalent interactions present within the molecules.

Currently, viral infection is the most serious health issue which causing unexpected higher rate of death globally. Many viruses are not yet curable, such as corona virus-2 (SARS-CoV-2), human immunodeficiency virus (HIV), hepatitis virus, human papilloma virus and so others. Furthermore, the toxicities and ineffective responses to resistant strains of synthetic antiviral drugs have reinforced the search of effective and alternative treatment options, such as plant-derived antiviral drug molecules. Therefore, in the present review, an attempt has been taken to summarize the medicinal plants reported for exhibiting antiviral activities available in Bangladesh along with discussing the mechanistic insights into their bioactive components against three most hazardous viruses, namely SARS-CoV-2, HIV, and HBV. The review covers 46 medicinal plants with antiviral activity from 25 families. Among the reported 79 bioactive compounds having antiviral activities isolated from these plants, about 37 of them have been reported for significant activities against varieties of viruses. Hesperidin, apigenin, luteolin, seselin, 6-gingerol, humulene epoxide, quercetin, kaempferol, curcumin, and epigallocatechin-3-gallate (EGCG) have been reported to inhibit multiple molecular targets of SARS-CoV-2 viral replication in a number of in silico investigations. Besides, numerous in silico , in vitro , and in vivo bioassays have been demonstrated that EGCG, anolignan-A, and B, ajoene, curcumin, and oleanolic acid exhibit anti-HIV activity while piperine, ursolic acid, oleanolic acid, (+)-cycloolivil-4′-O-β-d-glucopyranoside, quercetin, EGCG, kaempferol, aloin, apigenin, rosmarinic acid, andrographolide, and hesperidin possess anti-HBV activity. Thus, the antiviral medicinal plants and the isolated bioactive compounds may be considered for further advanced investigations with the aim of the development of effective and affordable antiviral drugs.

Citrus is a genus belonging to the Rutaceae family and includes important crops like orange, lemons, pummelos, grapefruits, limes, etc. Citrus essential oils (CEOs) consist of some major biologically active compounds like α-/β-pinene, sabinene, β-myrcene, d-limonene, linalool, α-humulene, and α-terpineol belonging to the monoterpenes, monoterpene aldehyde/alcohol, and sesquiterpenes group, respectively. These compounds possess several health beneficial properties like antioxidant, anti-inflammatory, anticancer, etc., in addition to antimicrobial properties, which have immense potential for food applications. Therefore, this review focused on the extraction, purification, and detection methods of CEOs along with their applications for food safety, packaging, and preservation. Further, the concerns of optimum dose and safe limits, their interaction effects with various food matrices and packaging materials, and possible allergic reactions associated with the use of CEOs in food applications were briefly discussed, which needs to be addressed in future research along with efficient, affordable, and “green” extraction methods to ensure CEOs as an ecofriendly, cost-effective, and natural alternative to synthetic chemical preservatives.

The development of eco-friendly biopesticides in the fight against agricultural pests is an important challenge nowadays. The essential oil of Wedelia prostrata Hemsl. is known for its multipurpose biological activities in Chinese folk medicine. However, limited efforts attempted to understand the potential insecticidal activity of its main individual constituents and related mechanism of action. In this research, we investigated the insecticidal activity of W. prostrata against the crop pest Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae). Toxicity on 4th instar larvae was assessed after 24 h of exposure. The LC 50 and LC 90 of the W. prostrata essential oil were 167.46 and 322.12 μg/ml, respectively. GC-MS analyses were carried out to shed light on the oil chemical composition. Main constituents were the monoterpene camphene (9.6%) and the sesquiterpenes γ-elemene (7.6%), α-humulene (6.9%), and ( E,E )-α-farnesene (7.3%). The pure constituents were evaluated for their insecticidal activity on S. litura 4th instar larvae. The most toxic molecule was camphene (LC 50  = 6.28 μg/ml), followed by γ-elemene, (LC 50  = 10.64 μg/ml), α-humulene (LC 50  = 12.89 μg/ml), and ( E,E )-α-farnesene (LC 50  = 16.77 μg/ml). Overall, our experiments highlighted the promising potential of camphene and γ-elemene from W. prostrata essential oil against larvae of S. litura , allowing us to propose these two compounds for the development of newer pesticides in the fight against crop pests. Further studies aimed at evaluating the potential synergy between these two molecules, as well as their stability in field conditions are ongoing.