Phenolic glycosides and monoterpenoids from the roots of Euphorbia ebracteolata and their bioactivities

Phytohormones enhance heavy metal responses in Euglena gracilis: Evidence from uptake of Ni, Pb and Cd and linkages to hormonomic and metabolomic dynamics

Over the last decade, significant effort has been made to understand phytohormonal functions (e.g., cytokinins (CKs) and abscisic acid (ABA)) in metal stress responses of higher plants and algae. Despite the potential for these phytohormones to improve industrial remediation by Euglena gracilis (Euglenophyceae), no such roles have been elucidated for this highly adaptive species and its response to heavy metals. This study demonstrates that toxic metals (nickel, lead, cadmium) modify hormonal activity profiles (i.e., CK forms and their concentrations) in E. gracilis. Furthermore, exogenous ABA or CK (tZ) enabled higher metal uptake efficiency (i.e., 9.35% in lead and 9.2% in cadmium uptake with CK) and alleviated metal toxicity through the regulation of endogenous CKs (i.e., total CK, isoprenoid CK) and gibberellin (GAs, GA₁ and GA₃) levels. These responses suggest that E. gracilis regulates multiple phytohormone signals during metal stress acclimation. A deeper approach, using untargeted metabolomic analyses, gave more detailed insight into phytohormone-controlled pathways and associated modified metabolites, which were frequently related to metal accumulation and the physiological acclimation to metal presence. Significant changes in the levels of cellular metabolites, especially those involved in acclimation to metal stress, were under the influence of phytohormones in algal cells. When grown under metal stress conditions, the presence of exogenous ABA or CKs, caused changes in cellular metabolites which included those from: lipid pathways, riboflavin metabolism, the biosynthesis of cofactors/vitamins, and carbohydrate metabolism. Also, bioactive secondary metabolites (e.g., terpenoids, alkaloids, flavonoids, carotenoids) were modified in algal cells treated with phytohormones. Thus, the study gives a detailed view on the regulatory functions of ABA and CKs in algal metal bioremediation strategies, which are attributed to enhanced metal uptake and in the fine-tuning of plant hormone levels during metal stress response. The results can guide efforts to develop efficient, low-cost and environmentally friendly methods for bioremediation.

Identifying Terpenoid Biosynthesis Genes in Euphorbia maculata via Full-Length cDNA Sequencing

The annual herb Euphorbia maculata L. produces anti-inflammatory and biologically active substances such as triterpenoids, tannins, and polyphenols, and it is used in traditional Chinese medicine. Of these bioactive compounds, terpenoids, also called isoprenoids, are major secondary metabolites in E. maculata. Full-length cDNA sequencing was carried out to characterize the transcripts of terpenoid biosynthesis reference genes and determine the copy numbers of their isoforms using PacBio SMRT sequencing technology. The Illumina short-read sequencing platform was also employed to identify differentially expressed genes (DEGs) in the secondary metabolite pathways from leaves, roots, and stems. PacBio generated 62 million polymerase reads, resulting in 81,433 high-quality reads. From these high-quality reads, we reconstructed a genome of 20,722 genes, in which 20,246 genes (97.8%) did not have paralogs. About 33% of the identified genes had two or more isoforms. DEG analysis revealed that the expression level differed among gene paralogs in the leaf, stem, and root. Whole sets of paralogs and isoforms were identified in the mevalonic acid (MVA), methylerythritol phosphate (MEP), and terpenoid biosynthesis pathways in the E. maculata L. The nucleotide information will be useful for identifying orthologous genes in other terpenoid-producing medicinal plants.

Carboxylesterase inhibitors from clinically available medicines and their impact on drug metabolism

Mammalian carboxylesterases (CES), the key members of the serine hydrolase superfamily, hydrolyze a wide range of endogenous substances and xenobiotics bearing ester or amide bond(s). In humans, most of identified CES are segregated into the CES1A and CES2A subfamilies. Strong inhibition on human CES (including hCES1A and hCES2A) may modulate pharmacokinetic profiles of CES-substrate drugs, thereby changing the pharmacological and toxicological responses of these drugs. This review covered recent advances in discovery of hCES inhibitors from clinically available medications, as well as their impact on CES-associated drug metabolism. Three comprehensive lists of hCES inhibitors deriving from clinically available medications including therapeutic drugs, pharmaceutical excipients and herbal medicines, alongside with their inhibition potentials and inhibition parameters, are summarized. Furthermore, the potential risks of hCES inhibitors to trigger drug/herb-drug interactions (DDIs/HDIs) and future concerns in this field are highlighted. Potent hCES inhibitors may trigger clinically relevant DDIs/HDIs, especially when these inhibitors are co-administrated with CES substrate-drugs with very narrow therapeutic windows. All data and knowledge presented here provide key information for the clinicians to assess the risks of clinically available hCES inhibitors on drug metabolism. In future, more practical and highly specific substrates for hCES1A/hCES2A should be developed and used for studies on CES-mediated DDIs/HDIs both in vitro and in vivo.

Euphorbia ebracteolata Hayata (Euphorbiaceae): A systematic review of its traditional uses, botany, phytochemistry, pharmacology, toxicology, and quality control

Euphorbia ebracteolata Hayata, as a traditional medicine, is widely distributed in China, Korea and Japan. In China, the dried root of this plant is named 'langdu'. It is traditionally used to treat oedema, skin ulcers, abdominal distension, cough, asthma, tuberculosis swelling and other diseases. Previous studies have found that the chemical constituents of E. ebracteolata are mainly concentrated in terpenoids, acetophenones, and flavonoids. Both extracts and pure compounds from E. ebracteolata were found to possess many pharmacological activities, such as anticancer, anti-inflammatory, antiviral, and antimicrobial effects. In addition, it was reported that E. ebracteolata shows toxicity. To provide inspiration for further in-depth studies on this plant, this review will provide a timely and systematic summary of E. ebracteolata in traditional uses, phytochemistry, pharmacology toxicology, and quality control.

Hitting the sweet spot: A systematic review of the bioactivity and health benefits of phenolic glycosides from medicinally used plants

Phenolic acid and flavonoid glycosides form a varied class of naturally occurring compounds, characterised by high polarity-resulting from the glycone moiety-and the presence of multiple phenol functionalities, which often leads to strong antioxidant activity. Phenolic glycosides, and in particular flavonoid glycosides, may possess strong bioactive properties with broad spectrum activity. This systematic literature review provides a detailed overview of 28 studies examining the biological activity of phenolic and flavonoid glycosides from plant sources, highlighting the potential of these compounds as therapeutic agents. The activity of glycosides depends upon the biological activity type, identity of the aglycone and the identity and specific location of the glycone moiety. From studies reporting the activity of both glycosides and their respective aglycones, phenolic glycosides appear to generally be a storage/reserve pool of precursors of more bioactive compounds. The glycosylated compounds are likely to be more bioavailable compared to their aglycone forms, due to the presence of the sugar moieties. Hydrolysis of the glycoside in the in vivo environment would release the free aglycone, potentiating their biological activity. However, further high-quality studies are needed to firmly establish the clinical efficacy of glycosides from many of the plant species studied.

Potential Pharmacokinetic Herb-Drug Interactions: Have we Overlooked the Importance of Human Carboxylesterases 1 and 2?

Background:

Herbal products have grown steadily across the globe and have increasingly been incorporated into western medicine for healthcare aims, thereby causing potential pharmacokinetic Herb-drug Interactions (HDIs) through the inhibition or induction of drug-metabolizing enzymes and transporters. Human Carboxylesterases 1 (CES1) and 2 (CES2) metabolize endogenous and exogenous chemicals including many important therapeutic medications. The growing number of CES substrate drugs also underscores the importance of the enzymes. Herein, we summarized those potential inhibitors and inducers coming from herbal constituents toward CES1 and CES2. We also reviewed the reported HDI studies focusing on herbal products and therapeutic agents metabolized by CES1 or CES2.

Methods:

We searched in PubMed for manuscript published in English after Jan 1, 2000 combining terms “carboxylesterase 1”, “carboxylesterase 2”, “inhibitor”, “inducer”, “herb-drug interaction”, “inhibitory”, and “herbal supplement”. We also searched specific websites including FDA and EMA. The data of screened papers were analyzed and summarized.

Results:

The results showed that more than 50 natural inhibitors of CES1 or CES2, including phenolic chemicals, triterpenoids, and tanshinones were found from herbs, whereas only few inducers of CES1 and CES2 were reported. Systemic exposure to some commonly used drugs including oseltamivir, irinotecan, and clopidogrel were changed when they were co-administered with herb products such as goldenseal, black cohosh, ginger, St. John’s Wort, curcumin, and some Chinese compound formula in animals.

Conclusion:

Nonclinical and clinical studies on HDIs are warranted in the future to provide safety information toward better clinical outcomes for the combination of herbal products and conventional drugs.

Isolation of CarE genes from the Chinese white pine beetle Dendroctonus armandi (Curculionidae: Scolytinae) and their response to host chemical defense

BACKGROUND

Bark beetles rely on detoxifying enzymes to resist the defensive terpenoids of their host trees. Research on carboxylesterases (CarEs) has focused on their multiple functions in the metabolic detoxification of pesticides and plant allelochemicals, drug resistance, and juvenile hormone and pheromone degradation.

RESULT

We identified eight new CarE genes in the Chinese white pine beetle (Dendroctonus armandi) and carried out bioinformatics analysis on the deduced full-length amino acid sequences. Differential transcript levels of CarE genes were observed between sexes; within these levels, significant differences were found among the different development stages, and between insects fed on the phloem of Pinus armandi and exposed to five stimuli [(-)-α-pinene, (-)-β-pinene, (+)-3-carene, limonene and turpentine] at 8 and 24 h.

CONCLUSION

Transcription levels of CarE genes suggest some relationship with the detoxification of terpenoids released by host trees. The functions of bark beetle esterase are mainly in hydrolyzing the host chemical defense and degrading odorant molecules during host selection and colonization. © 2018 Society of Chemical Industry.