Background/Objectives: Tropane alkaloids (TAs) and phenylpropanoid polyamine alkaloids (PPAs) are major alkaloid constituents of solanaceous plants; however, the tissue-specific distribution of these compounds in Anisodus luridus, a medicinal plant native to southeastern Xizang, remains incompletely characterized. Methods: A biosynthesis-informed putative annotation workflow was developed using ultra-performance liquid chromatography-high-resolution mass spectrometry (UPLC-HRMS) to characterize alkaloid profiles across seven tissues (root, stem, leaf, calyx, corolla, ovary, and seed). Putative annotations were guided by substrate-product structural relationships, predicted enzyme-catalyzed modifications, and diagnostic tandem mass spectrometry (MS/MS) fragmentation patterns. Results: Eighteen alkaloid features were characterized, comprising 6 TAs and 12 PPAs. Hyoscyamine and scopolamine were identified using authentic standards, and the remaining 16 features were putatively annotated, including dihydroanisodamine, hexosylhyoscyamine, and several PPAs not previously reported in A. luridus. TAs were predominantly enriched in roots and ovaries, whereas PPAs accumulated in floral tissues and leaves. Orthogonal partial least squares discriminant analysis (OPLS-DA) identified scopolamine (variable importance in projection (VIP) = 1.30) as a principal variable associated with separation among tissue metabolic profiles. Conclusions: This workflow supports the putative annotation of alkaloids in non-model medicinal plants. The observed tissue-specific distribution patterns provide a basis for future comparative studies with A. belladonna and for evaluating cultivation, tissue-selective harvesting, and extraction strategies.

Tropane alkaloids (TA) constitute a class of plant specialized metabolites with important pharmaceutical applications, including the anticholinergic agents hyoscyamine and scopolamine and the local anesthetic cocaine. Over the past decade, advances in genomics, structural biology, and synthetic biology have substantially revised our understanding of TA biosynthesis, leading to the identification of numerous key biosynthetic enzymes and evolutionary mechanisms. This review comprehensively summarizes current knowledge of TA biosynthesis from precursor formation to structurally diverse end products. We describe the pathway from putrescine to tropinone, the stereoselective metabolic branching mediated by Tropinone Reductases, and the downstream biosynthesis of medicinal tropane alkaloids, calystegines, and cocaine. Particular emphasis is placed on recent discoveries concerning catalytic mechanisms, structural determinants of substrate specificity, metabolic compartmentalization, and the convergent evolution of TA biosynthesis in Solanaceae and Erythroxylaceae. We further integrate advances in genomics, evolutionary biology, and metabolic engineering to highlight emerging strategies for microbial production and pathway redesign. By providing a comprehensive synthesis of recent progress and critical perspectives on unresolved questions, this review offers an updated framework for understanding TA biosynthesis and supports future research in plant specialized metabolism, synthetic biology, and natural product engineering.

Hyoscyamus albus L. is an endangered plant that is rich in tropane alkaloids (TAs), especially scopolamine and hyoscyamine, of valuable pharmaceutical interest. Owing to the complex and challenging chemical synthesis of TAs, developing new approaches to their production is necessary to meet the substantial pharmaceutical demand. Therefore, strategies employing biotechnology and nanotechnology are urgently needed to conserve the plant and enhance TA production. This is the first detailed study of Egyptian H. albus L. and on the elicitation of zinc oxide (Z) and zinc oxide nanoparticles (ZN) in callus and hairy root (HR) cultures of this species. The alkaloidal extracts of air-dried aerial parts, roots, calli, and hairy roots of H. albus L. were subjected to GC-MS to investigate their contents. Additionally, the effects of abiotic elicitors at different concentrations on the growth and atropine content of cultures of Egyptian H. albus L. were studied. Moreover, the antimicrobial and antivirulence activities of alkaloidal extracts of Egyptian H. albus L. were assessed against various microorganisms. GC/MS revealed the induction of tropinone in the in vitro cultures. Hairy roots (HRs) of Egyptian H. albus L. produced higher amounts of scopolamine and aposcopolamine than did the parent plant. ZnO (Z) is the most effective for atropine accumulation in callus cultures of H. albus L. Additionally, the most effective ones for productivity in hairy root (HR) tissue and media are ZnO nanoparticles (ZNs) and ZnO (Z), respectively. Alkaloid extracts of Egyptian H. albus L. exhibited promising antimicrobial and antivirulence activities. These findings shed light on the use of biotechnological tools and nanotechnology for the sustainable and improved production of pharmaceutically relevant phytocompounds.

Anisodus tanguticus is an important Tibetan medicinal plant. The tropane alkaloids (TAs), such as hyoscyamine, anisodamine, and scopolamine, exhibit significant analgesic and sedative pharmacological activities, making this species a valuable natural source for extracting these bioactive compounds. However, the chemical composition of A. tanguticus is highly complex. It includes a large number of compounds without elucidated structures, rendering systematic identification and structural characterization of its active constituents particularly important. Although high-performance liquid chromatography (HPLC) has been widely used for the separation of extracts from this plant, many unknown components remain challenging to accurately identify, even with spectral database matching. This study established an analytical method based on high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (HPLC-QQQ-MS) for the determination of tropane alkaloids in A. tanguticus. The method encompasses a series of systematic procedures, including standardized sample preparation, mass spectrometric parameter configuration, LC pre-equilibration, method establishment, acquisition of MS data, multistage mass spectrometry (MS[n]) scanning, and manual data interpretation. Using this strategy, we successfully identified three representative tropane alkaloids in A. tanguticus: hyoscyamine, anisodamine, and scopolamine. Additionally, it validates the precision of the established HPLC-QQQ-MS method, confirming that the method is rapid, sensitive, feasible, and accurate for the quantitative determination of tropane alkaloids (TAs) in A. tanguticus. The established approach demonstrates good versatility and reliability, and is suitable for the high-throughput identification and quantification of tropane alkaloids in A. tanguticus and other medicinal plants.

Plant chemistry and toxicology are complex fields with a rich history. Much of plant chemistry remains incompletely characterized, and current understanding derives from animal research combined with documented human experience. The dynamic science of pharmacognosy, which highlights the therapeutic value of plants, has elucidated several major classes of organic molecules found in plants, with alkaloids representing one such class. Other major classes include phenols and phenylpropanoids; terpenes and resins; glycosides; and proteins, peptides, and lectins. Plant alkaloids comprise a diverse group of secondary plant metabolites exemplified by familiar compounds, such as nicotine, caffeine, cocaine, mescaline, ephedrine, and strychnine. Plant alkaloids are generally defined as basic compounds containing 1 or more nitrogen atoms within a heterocyclic structure. Plant alkaloids typically exhibit potent pharmacologic activity and serve as components of plant chemical defense systems. A given plant species may contain 1, a few, or many alkaloids, as observed in Papaveraceae (poppy) and Solanaceae (nightshade). Most plant alkaloids in pure form are nonvolatile, colorless crystalline solids with a bitter taste. Plant alkaloids possess both toxic and therapeutic properties, as illustrated by the antineoplastic effects of the vinca alkaloids and the genotoxic effects of the pyrrolizidine alkaloids. Additional examples include disruption of cholinergic neurotransmission by hyoscyamine and the therapeutic potential of the procholinergic agent galantamine in neurodegenerative disorders such as Alzheimer disease. In certain cases, an alkaloid may serve as an antidote to another alkaloid with toxic properties. Advances in chemistry, repurposing, and metabolic engineering have enabled broad exploitation of plant alkaloids for medicinal applications since the discovery of morphine. Such applications include the treatment of pain (eg, morphine, cocaine), fever (eg, quinine), malignancy (eg, vinblastine, berberine), asthma (eg, ephedrine), dysrhythmias (eg, quinidine), hyperglycemia (eg, piperine), hypertension (eg, reserpine), and bacterial infections (eg, ciprofloxacin). This activity synthesizes available evidence to highlight the toxic effects of these metabolites, exposure to which may result in disease.

Atropa belladonna L. (Solanaceae) is a significant source of the pharmacologically important tropane alkaloids (TAs), particularly hyoscyamine and scopolamine. Although rolB and rolC from Rhizobium rhizogenes are known to enhance plant secondary metabolism, their functional specificities and combined actions in TAs biosynthesis remain unclear. Here, we generated transgenic A. belladonna overexpressing 35S::rolB, 35S::rolC, and 35S::rolB + rolC to systematically investigate their effects on TAs accumulation, plant morphology, and drought tolerance. Co-expression of rolB and rolC exhibited metabolic antagonism, with TAs levels significantly lower than in rolC single transgenic plants, further establishing rolC as the primary regulator of this pathway. Phenotypic analysis revealed divergent effects: rolB increased leaf size and promoted root growth, whereas rolC caused dwarfism, early flowering, and male sterility; double transgenic plants displayed exacerbated growth inhibition. Notably, rolC-expressing plants showed improved drought performance via combined morphological and antioxidant adjustments. Mechanistically, both genes upregulated key biosynthetic genes, with rolC regulating a broader set. Protein interaction assays revealed that RolC directly interacts with TRI, calmodulin (CaM1/CaM7), and the brassinosteroid signaling component BSK. A root-specific transcription factor, AbbHLH30, was identified as a candidate downstream component of the RolC-CaM1 module, with the capacity to activate H6H expression in transient assays. This study provides a mechanistic basis for understanding rol gene functions and offers specific molecular targets for engineering TAs production in A. belladonna.

Covering: 2018 to 2025Alkaloids represent a large and structurally diverse class of natural products predominantly found in plants and rarely in animals. Well-known compounds such as vinblastine, berberine, and scopolamine exhibit remarkable pharmaceutical potential, with several already in clinical use. These plant-derived alkaloids have attracted enduring interest due to their diversity, structural complexity, and pronounced biological activities, making them a privileged resource for drug discovery. In recent years, breakthrough advances have been made in elucidating the biosynthetic pathways of plant alkaloids, making this a highly promising research field. Successful cases including reserpine, strychnine, and hyoscyamine have not only provided novel strategies for drug development and sustainable production, but also greatly stimulated scientific enthusiasm. In this review, we focus on representative plant alkaloids from major classes including monoterpene indole alkaloids (MIAs), tetrahydroisoquinoline alkaloids (THIQAs), tropane alkaloids (TAs), and other types, covering the period from 2018 to 2025. It highlights key challenges in pathway elucidation, including stereochemical control (R/S configuration), important cyclization, and tailoring modifications particularly those catalyzed by specific enzymes. This review also covers catalytic sequence determination, and innovative approaches for long-pathway decoding. Furthermore, we discuss how synthetic biology and metabolic engineering strategies enable efficient and sustainable microbial production of these compounds. By identifying common obstacles and proposing effective solutions, this review aims to inspire researchers engaged in functional gene characterization, synthetic biosystems development, yield optimization, and drug innovation for plant alkaloids. It seeks to promote interdisciplinary collaboration across botany, chemistry, biology, and pharmaceutical sciences, thereby accelerating the discovery and scalable production of high-value plant alkaloids.

Whole-cell biocatalysis offers a sustainable alternative to traditional chemical synthesis for producing pharmaceutically relevant, often chiral, amines and amino acids. Saccharomyces cerevisiae has emerged as a privileged microbial chassis due to its robustness, ease of genetic manipulation, and GRAS status. This concise review summarizes recent advances in metabolic and genetic engineering of S. cerevisiae for amine biocatalysis, focusing on strategies to overcome bottlenecks such as enzyme gene expression, cofactor regeneration, and precursor channeling. The first section covers state-of-the-art methods for engineered strain construction, including genomic editing, optimization of gene expression (copy number, promoters, terminators, codon usage), and metabolic engineering (pathway balancing, compartmentalization, cofactor supply, transport proteins, auxiliary enzymes, and enzyme targeting via signal peptides), all enhancing product yields and enabling complex amine synthesis. The central section critically discusses compound families accessible via engineered S. cerevisiae, including various amines, amino alcohols, and amino acids such as l-carnitine, ergothioneine, halogenated tryptamine, serotonin, psilocybin, spermidine, l-ornithine, and mycosporine derivatives. Bioproduction of complex alkaloids, such as tropine derivatives (hyoscyamine and scopolamine) and ergot alkaloids, is also reviewed. Finally, current challenges and future perspectives are outlined, highlighting the integration of systems and synthetic biology tools to establish S. cerevisiae as a scalable platform for industrial amine production.

The use of herbal medicines is expanding rapidly, and reputable pharmaceutical companies are increasing the proportion of effective herbal compounds in the production of drugs used to treat conditions such as cancer and neurological disorders. The commercial-scale production of these natural metabolites by plants remains limited, necessitating the application of modern technologies to enhance their yield. In the present study, the effects of various concentrations of silicon dioxide nanoparticles (SiO₂ NPs) as an elicitor (0, 100, and 200 mg/L) and different precursors (no precursor, phenylalanine, and putrescine at 3 mM) on the growth and phytochemical traits of Hyoscyamus reticulatus hairy roots were investigated. Hairy roots gradually appeared from the wound sites two weeks after inoculation. The highest fresh weight (FW) (3.57 g) was observed in the putrescine precursor treatment, while the maximum dry weight (DW) (0.73 g) was recorded in the control group. The highest total phenolic content (TPC) (7.79 mg GA/g FW) was observed with the putrescine precursor, while the highest total flavonoid content (TFC). (1.79 mg QUE/g FW) was obtained with the phenylalanine precursor, both in the absence of the elicitor. HPLC analysis revealed that the highest levels of hyoscyamine (165.4 µg/g DW) and scopolamine (91.3 µg/g DW) were detected in hairy roots treated with 200 mg/L SiO₂ NPs combined with putrescine precursor. These findings suggest that the combined use of elicitors and precursor feeding in transgenic hairy root cultures of H. reticulatus can significantly enhance the production of tropane alkaloids, such as hyoscyamine and scopolamine.

The triticeal cartilage is a small cartilage found within the thyrohyoid membrane present in approximately 33%-53% of individuals. Rarely, calcification/ossification of this cartilage can occur, leading to symptoms of dysphagia, odynophagia, or globus sensation. Despite its clinical relevance, symptomatic triticeal cartilage calcification remains poorly characterized in the literature, with only isolated case reports and no established diagnostic or management framework. We present a case of a 44-year-old woman who presented with seven months of atypical throat and neck pain and globus sensation in the setting of prior esophagogastroduodenoscopy with dilation. Medical management, including nortriptyline and hyoscyamine provided no benefit. Physical examination and flexible laryngoscopy were unremarkable, except for focal left-sided neck tenderness. Contrast-enhanced computed tomography of the neck demonstrated a nonspecific 0.3 x 0.3 x 1.0 cm submucosal calcification at the thyrohyoid membrane, suspicious for retained foreign body. The patient underwent left neck exploration which revealed a calcified cartilaginous structure embedded within the pharyngeal constrictors and immediately adjacent to a pharyngeal plexus branch. Final pathology confirmed fibrous tissue and cartilage. The patient reported immediate, complete symptom resolution and remained symptom-free at 13-month follow-up. This case highlights calcified triticeal cartilage as a rare, often overlooked cause of persistent throat symptoms. Recognition of this pathology may prevent misdiagnosis and allow for timely, definitive treatment.

The Solanaceae family comprises numerous species of economic and pharmacological importance, including the toxic deadly nightshade (Atropa belladonna), bittersweet nightshade (Solanum dulcamara), and black nightshade (Solanum nigrum). These plants are native to Europe, North Africa, and Western Asia, and have been used since ancient times in both ritual practices and medicine. A. belladonna contains potent tropane alkaloids (atropine, hyoscyamine, and scopolamine) and is widely utilized in modern pharmacology, although accidental poisonings still occur, often due to confusion with edible plants or the misuse of herbal and homeopathic preparations. In contrast, S. dulcamara contains glycoalkaloids such as solanine, solasodine, and β-solamarine, while S. nigrum contains solanine, solamargine, and solasonine. Both species have a history of traditional use as narcotics, diuretics, and treatments for skin, rheumatic, and respiratory conditions, as well as for pain, inflammation, fever, and other disorders; however, they also pose significant toxicological risks to humans and animals. Although poisonings from these two species are less common than those caused by A. belladonna, they still occur. A review of the literature identified 41 studies reporting poisoning cases associated with these plants, primarily resulting from berry ingestion. Poisoning typically produces anticholinergic syndrome, underscoring the importance of accurate identification and prompt treatment.