We summarize the history and review the literature on isoprene in exhaled breath and discuss the current evidence and models that describe its endogenous origin and consequence for understanding isoprene levels and their variations in exhaled breath.

Sesquiterpenes are important in human health because they can treat viral infection, cardiovascular disease, and cancer. Sesquiterpenes have also been shown to increase the sensitivity of tumor cells to conventional pharmacological therapies, in addition to their antiviral effects. The present review article was drafted with an intention to gather information regarding sesquiterpenes and its medicinal importance. The role of sesquiterpenes in the endogenous production of sesquiterpenes by plants and fungi, as well as the mechanisms by which they are effective against viral infection, are discussed in this review. Different online libraries such as PUBMED, Sciencedirect, MEDLINE were assessed to gather information, additionally, books, magzagines, journals, and scientific newspapaers were also studied to make this article more informative. This review examines novel synthesis mechanisms, their cyclization, purification techniques, and the diverse ecological roles sesquiterpenes play in the plant producer, which varies according to the plant and the chemical under consideration. In this article, we have discussed the consequences of sesquiterpenes and their properties for future crop productivity. We have addressed the many forms of sesquiterpenes that have been shown to have antiviral activity in various diseases. The consequences of sesquiterpenes and their properties are very useful for future crop productivity. We have addressed the many forms of sesquiterpenes that have been shown to have antiviral activity in the treatment of various diseases. PRACTICAL APPLICATIONS: Novel synthesis mechanisms, their cyclization, purification techniques, and the diverse ecological roles of sesquiterpenes will be very helfpul in drug development process. Sesquiterpene lactones are shown in this review to have qualities that warrant further scientific investigation in order to stimulate preclinical and clinical trials leading to the creation of novel medications. For antiviral drug development, the sesquiterpenes are a good prospective lead molecule because they can suppress viral replication by disrupting vRNA production and viral protein production.

Biogenic volatile organic compounds (BVOCs), particularly terpenoids, can significantly drive the formation of ozone (O3) and secondary organic aerosols (SOA) in the atmosphere, as well as directly or indirectly affect global climate change. Understanding their emission mechanisms and the current progress in emission measurements and estimations are essential for the accurate determination of emission characteristics, as well as for evaluating their roles in atmospheric chemistry and climate change. This review summarizes the mechanisms of terpenoid synthesis and release, biotic and abiotic factors affecting their emissions, development of emission observation techniques, and emission estimations from hundreds of published papers. We provide a review of the main observations and estimations in China, which contributes a significant proportion to the total global BVOC emissions. The review suggests the need for further research on the comprehensive effects of environmental factors on terpenoid emissions, especially soil moisture and nitrogen content, which should be quantified in emission models to improve the accuracy of estimation. In China, it is necessary to conduct more accurate measurements for local plants in different regions using the dynamic enclosure technique to establish an accurate local emission rate database for dominant tree species. This will help improve the accuracy of both national and global emission inventories. This review provides a comprehensive understanding of terpenoid emissions as well as prospects for detailed research to accurately describe terpenoid emission characteristics worldwide and in China.

OBJECTIVE: Terpenes are natural compounds found in several organisms belonging to the animal and plant kingdom, therefore, constitute the largest class of natural products and were a rich reservoir of candidate compounds for drug discovery. The review aims to focus on the extensive potential of the anti-cancer terpenoid components obtained from natural plant species which may lead to the development of a variety of derived terpenoids moieties.
METHODS: Literature survey has been carried out to determine the potential of terpenoids.
RESULTS: The present article provides an overview of the development of the isoprene unit and the generation of the various types of terpenes that exhibits pharmacological potential. The anti-cancer activity of terpenoids appears promising and will potentially open more opportunities for cancer therapy. However, current studies are restricted to descriptive findings and some of them lack mechanistic insights and systematic structure--activity relationship studies. Future efforts into the systematic identification of the targets of terpenoids are believed to increase the chances of gaining breakthrough insights in the field.
CONCLUSIONS: There is still hope that new therapeutic options for the control of cancer and any other painful syndromes will be developed from terpenes, which were proved to be great candidates for cancer therapeutics.

Isoprene and monoterpenes (MTs) are among the most abundant and reactive volatile organic compounds produced by plants (biogenic volatile organic compounds). We conducted a meta-analysis to quantify the mean effect of environmental factors associated to climate change (warming, drought, elevated CO2 , and O3 ) on the emission of isoprene and MTs. Results indicated that all single factors except warming inhibited isoprene emission. When subsets of data collected in experiments run under similar change of a given environmental factor were compared, isoprene and photosynthesis responded negatively to elevated O3 (-8% and -10%, respectively) and drought (-15% and -42%), and in opposite ways to elevated CO2 (-23% and +55%) and warming (+53% and -23%, respectively). Effects on MTs emission were usually not significant, with the exceptions of a significant stimulation caused by warming (+39%) and by elevated O3 (limited to O3 -insensitive plants, and evergreen species with storage organs). Our results clearly highlight individual effects of environmental factors on isoprene and MT emissions, and an overall uncoupling between these secondary metabolites produced by the same methylerythritol 4-phosphate pathway. Future results from manipulative experiments and long-term observations may help untangling the interactive effects of these factors and filling gaps featured in the current meta-analysis.

With the global increase of tropospheric ozone (O3) and complex interactions between biogenic volatile organic compounds (BVOCs) emissions and tropospheric O3 concentrations, this review summarizes current research progress and future research prospects in terms of the effects of elevated O3 on BVOCs emissions. The main progress included impacts of BVOCs categories, plant functional types, O3 sensitivity of plants, the O3 stress level on the response of BVOCs emissions to single O3 stress, and the combined effects of elevated O3 and temperature, carbon dioxide (CO2), drought, and nitrogen (N) deposition. Results indicated that most published results reported no change in BVOCs emissions in response to increasing O3 concentration. Specifically, decreasing effects of O3 on BVOCs emissions were more obvious in studies on isoprene and deciduous species, whereas studies on monoterpenes and evergreen plant species showed more results with an increasing trend as well as acute O3 exposure experiments. There was an increased tendency of monoterpene emissions to the combined effects of O3 and temperature or N deposition. However, the combined effects of O3 and CO2 decreased isoprene emissions. Given that studies on the effects of O3 on BVOCs emissions remain scarce, more complete experiments are needed that consider differences between short-term and long-term or individual-level and ecosystem-level. Furthermore, future research should strengthen the multi-factor interactive studies, particularly on O3 and other global change components and biotic and abiotic stresses, to assess BVOCs emissions from terrestrial ecosystems in response to O3 pollution both currently and in the future, which will provide valuable theoretical support to air pollution control.

Isoprene, the ubiquitous, highly emitted non-methane volatile hydrocarbon, affects atmospheric chemistry and human health, and this makes its removal from the contaminated environment imperative. Physicochemical degradation of isoprene is inefficient and generates secondary pollutants. Therefore, biodegradation can be considered as the safer approach for its efficient abatement. This review summarizes efforts in this regard that led to tracking the diverse groups of isoprene degrading bacteria such as Methanotrophs, Xanthobacter, Nocardia, Alcaligenes, Rhodococcus, Actinobacteria, Alphaproteobacteria, Bacteriodetes, Pseudomonas, and Alcanivorax. Biodegradation of isoprene by such bacteria in batch and continuous modes has been elaborated. The products, pathways and the key enzymes associated with isoprene biodegradation have also been presented.