Seasonal and Differential Sesquiterpene Accumulation in Artemisia annua Suggest Selection Based on Both Artemisinin and Dihydroartemisinic Acid may Increase Artemisinin in planta

Biosynthesis of Phytocannabinoids and Structural Insights: A Review

Cannabis belongs to the family Cannabaceae, and phytocannabinoids are produced by the Cannabis sativa L. plant. A long-standing debate regarding the plant is whether it contains one or more species. Phytocannabinoids are bioactive natural products found in flowers, seeds, and fruits. They can be beneficial for treating human diseases (such as multiple sclerosis, neurodegenerative diseases, epilepsy, and pain), the cellular metabolic process, and regulating biological function systems. In addition, several phytocannabinoids are used in various therapeutic and pharmaceutical applications. This study provides an overview of the different sources of phytocannabinoids; further, the biosynthesis of bioactive compounds involving various pathways is elucidated. The structural classification of phytocannabinoids is based on their decorated resorcinol core and the bioactivities of naturally occurring cannabinoids. Furthermore, phytocannabinoids have been studied in terms of their role in animal models and antimicrobial activity against bacteria and fungi; further, they show potential for therapeutic applications and are used in treating various human diseases. Overall, this review can help deepen the current understanding of the role of biotechnological approaches and the importance of phytocannabinoids in different industrial applications.

Towards greenhouse cultivation of Artemisia annua: The application of LEDs in regulating plant growth and secondary metabolism

Artemisinin is a sesquiterpene lactone produced in glandular trichomes of Artemisia annua, and is extensively used in the treatment of malaria. Growth and secondary metabolism of A. annua are strongly regulated by environmental conditions, causing unstable supply and quality of raw materials from field grown plants. This study aimed to bring A. annua into greenhouse cultivation and to increase artemisinin production by manipulating greenhouse light environment using LEDs. A. annua plants were grown in a greenhouse compartment for five weeks in vegetative stage with either supplemental photosynthetically active radiation (PAR) (blue, green, red or white) or supplemental radiation outside PAR wavelength (far-red, UV-B or both). The colour of supplemental PAR hardly affected plant morphology and biomass, except that supplemental green decreased plant biomass by 15% (both fresh and dry mass) compared to supplemental white. Supplemental far-red increased final plant height by 23% whereas it decreased leaf area, plant fresh and dry weight by 30%, 17% and 7%, respectively, compared to the treatment without supplemental radiation. Supplemental UV-B decreased plant leaf area and dry weight (both by 7%). Interestingly, supplemental green and UV-B increased leaf glandular trichome density by 11% and 9%, respectively. However, concentrations of artemisinin, arteannuin B, dihydroartemisinic acid and artemisinic acid only exhibited marginal differences between the light treatments. There were no interactive effects of far-red and UV-B on plant biomass, morphology, trichome density and secondary metabolite concentrations. Our results illustrate the potential of applying light treatments in greenhouse production of A. annua to increase trichome density in vegetative stage. However, the trade-off between light effects on plant growth and trichome initiation needs to be considered. Moreover, the underlying mechanisms of light spectrum regulation on artemisinin biosynthesis need further clarification to enhance artemisinin yield in greenhouse production of A. annua.

A severe case of Plasmodium falciparum malaria imported by a French traveler from Cameroon to French Guiana despite regular intake of Artemisia annua herbal tea

The use of herbal tea with Artemisia annua by travelers and traditional communities in Africa has increased in recent years as a supposed form of malaria prophylaxis, although its use is not recommended due to lack of efficacy. The risk of severe malaria complications that can lead to death is real regarding said behavior, and awareness needs to be raised. We report a case of severe Plasmodium falciparum malaria imported in the Amazon rainforest by a traveler returning from Cameroon who treated himself with Artemisia annua herbal tea.

Enhancing artemisinin content in and delivery from Artemisia annua: a review of alternative, classical, and transgenic approaches

This review analyses the most recent scientific research conducted for the purpose of enhancing artemisinin production. It may help to devise better artemisinin enhancement strategies, so that its production becomes cost effective and becomes available to masses. Malaria is a major threat to world population, particularly in South-East Asia and Africa, due to dearth of effective anti-malarial compounds, emergence of quinine resistant malarial strains, and lack of advanced healthcare facilities. Artemisinin, a sesquiterpene lactone obtained from Artemisia annua L., is the most potent drug against malaria and used in the formulation of artemisinin combination therapies (ACTs). Artemisinin is also effective against various types of cancers, many other microbes including viruses, parasites and bacteria. However, this specialty metabolite and its derivatives generally occur in low amounts in the source plant leading to its production scarcity. Considering the importance of this drug, researchers have been working worldwide to develop novel strategies to augment its production both in vivo and in vitro. Due to complex chemical structure, its chemical synthesis is quite expensive, so researchers need to devise synthetic protocols that are economically viable and also work on increasing the in-planta production of artemisinin by using various strategies like use of phytohormones, stress signals, bioinoculants, breeding and transgenic approaches. The focus of this review is to discuss these artemisinin enhancement strategies, understand mechanisms modulating its biosynthesis, and evaluate if roots play any role in artemisinin production. Furthermore, we also have a critical analysis of various assays used for artemisinin measurement. This may help to develop better artemisinin enhancement strategies which lead to decreased price of ACTs and increased profit to farmers.

The Biochemistry of Phytocannabinoids and Metabolic Engineering of Their Production in Heterologous Systems

The medicinal properties of cannabis and the its legal status in several countries and jurisdictions has spurred the massive growth of the cannabis economy around the globe. The value of cannabis stems from its euphoric activity offered by the unique phytocannabinoid tetrahydrocannabinol (THC). However, this is rapidly expanding beyond THC owing to other non-psychoactive phytocannabinoids with new bioactivities that will contribute to their development into clinically useful drugs. The discovery of the biosynthesis of major phytocannabinoids has allowed the exploration of their heterologous production by synthetic biology, which may lead to the industrial production of rare phytocannabinoids or novel synthetic cannabinoid pharmaceuticals that are not easily offered by cannabis plants. This review summarizes the biosynthesis of major phytocannabinoids in detail, the most recent development of their metabolic engineering in various systems, and the engineering approaches and strategies used to increase the yield.

Differential Effects of Components in Artemisia annua Extract on the Induction of Drug-Metabolizing Enzyme Expression Mediated by Nuclear Receptors

Artemisia annua tea is a popular dosage form used to treat and prevent malaria in some developing countries. However, repeated drinking leads to an obviously decreased efficacy, which may be related to the induction of metabolizing enzymes by artemisinin. In the present study, the ability of different components in A. annua to activate the pregnane X receptor and constitutive androstane receptor was evaluated by the dual luciferase reporter gene system. The changes in mRNA and protein expression of CYP3A4 and CYP2B6 were determined by quantitative real-time PCR and Western blotting. Results showed that in the pregnane X receptor-mediated CYP3A4 reporter gene system, chrysosplenetin and arteannuin B exhibited a weak induction effect on pregnane X receptor wt, while arteannuin A had a strong induction effect on pregnane X receptor wt and pregnane X receptor 370 and a weak induction effect on pregnane X receptor 163. In the pregnane X receptor-mediated CYP2B6 reporter gene system, arteannuin A had a moderate induction effect on pregnane X receptor wt and pregnane X receptor 379, and a weak induction effect on pregnane X receptor 403, while arteannuin B had a weak induction effect on pregnane X receptor wt and pregnane X receptor 379. Arteannuin A had a strong induction effect on constitutive androstane receptor 3 in constitutive androstane receptor-mediated CYP3A4/2B6 reporter gene systems, while arteannuin B showed a weak induction effect on constitutive androstane receptor 3 in the constitutive androstane receptor-mediated CYP2B6 reporter gene system. The mRNA and protein expressions of CYP3A4 and CYP2B6 were increased when the pregnane X receptor or constitutive androstane receptor was activated. Various components present in A. annua differentially affect the activities of pregnane X receptor isoforms and the constitutive androstane receptor, which indicates the possibility of a drug-drug interaction. This partly explains the decline in efficacy after repeated drinking of A. annua tea.

Quantitative Analysis of Eight Triterpenoids and Two Sesquiterpenoids in Rhizoma Alismatis by Using UPLC-ESI/APCI-MS/MS and Its Application to Optimisation of Best Harvest Time and Crude Processing Temperature

Rhizoma Alismatis (RA), widely known as "Ze-Xie" in China, is the tuber of Alisma orientale (Sam.) Juzep (Alismaceae), a Chinese herbal medicine that has been used to treat hyperlipidemia, diabetes, hypertension, dysuria, and inflammation. In this study, a sensitive and reliable method based on an ultra-performance liquid chromatography (UPLC) couple with two ionisation modes, including electrospray ionisation (ESI) and atmospheric pressure chemical ionisation (APCI) tandem mass spectrometry (MS), namely, UPLC-ESI/APCI-MS/MS was developed and validated to simultaneously determine 8 triterpenoids (ESI mode) and 2 sesquiterpenoids (APCI mode) in RA. Ten marker compounds were analysed with a Waters' CORTECS UPLC C18 column (200 mm × 2.1 m, 1.6 μm) and gradient elution with water (contained 0.1% formic) and acetonitrile within 7 min. The established method was validated for linearity, intra- and interday precisions, accuracy, recovery, and stability. The calibration curve for 10 marker compounds showed good linear regression (r > 0.9971). The limits of detection and quantification for analytes were 0.14-1.67 ng/mL and 0.44-5.65 ng/mL, respectively. The relative standard deviations (RSD, %) and accuracy (RE, %) of intra- and interday precisions were less than 3.83% and 1.21% and 3.22% and 1.46%, repeatability and stability for real samples were less than 2.78% and 3.19%, respectively. All recoveries of the 10 marker compounds ranged from 97.24% to 102.49% with RSDs less than 4.05%. The developed method efficiently determined the 10 marker compounds in RA and was subsequently applied to optimise harvest time and crude processing temperature. The result indicated the 90% wilted phase and 70°C (or lower) may be the best harvest time and the processing temperature of RA.