Sucrose is a natural product occurs widely in nature. In living organisms such as plants, sucrose phosphate synthase (SPS) is the key rate-limiting enzyme for sucrose synthesis. SPS catalyzes the synthesis of sucrose-6-phosphate, which is further hydrolyzed by sucrose phosphatase to form sucrose. Researches on SPS in recent decades have been focused on the determination of enzymatic activity of SPS, the identification of the inhibitors and activators of SPS, the covalent modification of SPS, the carbohydrate distribution in plants regulated by SPS, the mechanism for promoting plant growth by SPS, the sweetness of fruit controlled by SPS, and many others. A systematic review of these aspects as well as the crystal structure and catalytic mechanism of SPS are presented.
Carbohydrate Metabolism ; Glucosyltransferases/metabolism* ; Plants/metabolism* ; Sucrose

Podophyllotoxin (PTOX) is an extremely important plant-derived natural product, of which derivatives, like etoposide and teniposide, have been widely applied in therapies for cancers and venereal wart. A durable, intense plant extraction of podophyllotoxin posed a severe pressure on wild resources; researchers consequently sought to explore new sources, like cultivation, plant cell or organ culture, and chemical synthesis. Understanding biosynthesis of PTOX is one of the basic necessary steps for standard cultivation of medicinal plants and metabolite engineering. An important progress has been made in this field during the last two decades, particularly in the last ten years. Although a number of reviews concerning the related topic have existed, we specifically deal with biosynthesis of podophyllotoxin with an emphasis on the literatures of the past decade, highlighting characterization of genes encoding synthetic enzymes and down-stream metabolism of PTOX. The present review focuses on several key biosynthesis processes, important metabolites, function of related enzymes, and characterization of cDNA encoding the enzymes. Finally, the author proposed a hypothetical biosynthetic scheme of podophyllotoxin and perspectives.
Plants, Medicinal ; metabolism ; Podophyllotoxin ; biosynthesis ; chemistry ; metabolism

Plant serine carboxypeptidase-like acyltransferases (SCPL-AT) have similar structural characteristics and high homology compared to the serine carboxypeptidase. They can transfer the acyl from acyl glucose esters to many natural products, participate in the acylation modification of plant secondary metabolites, enrich the structural diversity of natural products, and improve the physicochemical properties such as water solubility and stability of compounds. This review summarizes the structural characteristics, catalytic mechanism, functional characterization, and biocatalytic applications of SCPL-AT from plants. This will help to promote the functional characterization of these acyltransferase genes and the biosynthesis of useful plant secondary metabolites by synthetic biotechnology.
Acylation ; Acyltransferases/metabolism* ; Carboxypeptidases/metabolism* ; Plants/enzymology*

OBJECTIVETo estimate the heavy metal content in soil and selected medicinal plants procured from environmentally different sites of the same city.

METHODSSoil and plant samples of Abutilon indicum, Calotropis procera, Euphorbia hirta, Peristrophe bycaliculata, and Tinospora cordifolia were collected from 3 environmentally different sites of the city: heavy traffic area (HTA), industrial area (IA), and residential area (RA). Pb, Cd, Cr, and Ni were estimated in soil and plant samples by inductively coupled plasma emission spectrometry and compared.

RESULTSThe level of heavy metal was higher in soil than in plant parts studied. Accumulation of heavy metals varied from plant to plant. Pb was the highest in Calotropis procera root from HTA site and the lowest in Peristrophe bycaliculata whole plant from IA site. It was also lower in residential area than in heavy traffic area.

CONCLUSIONThe level of heavy metal content differed in the same medicinal plant collected from environmentally different sites of the same city. Thus, it reiterates our belief that every medicinal plant sample should be tested for contaminant load before processing it further for medication.

Phenylpropanoid metabolic pathway is one of the most important secondary metabolic pathways in plants. It directly or indirectly plays an antioxidant role in plant resistance to heavy metal stress, and can improve the absorption and stress tolerance of plants to heavy metal ions. In this paper, the core reactions and key enzymes of the phenylpropanoid metabolic pathway were summarized, and the biosynthetic processes of key metabolites such as lignin, flavonoids and proanthocyanidins and relevant mechanisms were analyzed. Based on this, the mechanisms of key products of phenylpropanoid metabolic pathway in response to heavy metal stress were discussed. The perspectives on the involvement of phenylpropanoid metabolism in plant defense against heavy metal stress provides a theoretical basis for improving the phytoremediation efficiency of heavy metal polluted environment.
Plants/metabolism* ; Metals, Heavy/metabolism* ; Flavonoids/metabolism* ; Biodegradation, Environmental ; Antioxidants

Plant-derived exosome-like nanoparticles(PELNs) are a class of membranous vesicles with diameters approximately ranging from 30 to 300 nm, isolated from plant tissues. They contain components such as proteins, lipids, and nucleic acids. PELNs play an important role in the metabolism of plant substances and immune defense, and can also cross-regulate the physiological activities of fungi and animal cells, showing significant potential applications. In recent years, research on PELNs has significantly increased, highlighting three main issues:(1) the mixed sources of plant materials for PELNs;(2) the lack of a unified system for isolating and characterizing PELNs;(3) the urgent need to elucidate the molecular mechanisms underlying the cross-regulation of biological functions by PELNs. This article focused on these concerns. It began by summarizing the biological origin and composition of PELNs, discussing the techniques for isolating and characterizing PELNs, and analyzing their biomedical applications and potential future research directions., aiming to promote the establishment of standardized research protocols for PELNs and provide theoretical references for in-depth exploration of the mechanisms underlying PELNs' cross-regulatory effects.
Animals ; Exosomes/metabolism* ; Proteins/metabolism* ; Plants/metabolism* ; Nucleic Acids ; Nanoparticles

Hormesis describes the low-dose stimulation and high-dose inhibition phenomena for all kind lives under toxicity environment. This paper generalized hormesis of medicinal plant on grow and metabolite after introducing the concept and study state of hormesis and analyzing hormesis mechanism and its significance. It points out that hormesis can be well used for medicinal plants growth, including increasing the metabolise, giving a dereaction for cultivated field chosen, guiding the agriculture management during the cultivation and improving the anti-stress.
Agriculture ; methods ; Plants, Medicinal ; growth & development ; metabolism

There exists many kinds and a huge number of terpenoid in medicinal plants, which show a wide range of pharmacological activities. 3-Hydroxy-3-metllylglutaryl coenzyme A reductase(HMGR) is a key rate-limiting enzyme in terpenoid biosynthetic pathway . HMGR plays an important role in the regulation of secondary metabolism of the terpenoid. The paper summarized the biological function and the catalytic mechanism of HMGR, the cloning and the structure of the gene as well as its research progress in some medicinal plants.
Hydroxymethylglutaryl CoA Reductases ; metabolism ; Plants, Medicinal ; enzymology ; Terpenes ; metabolism

Plants provide an immense reservoir of natural secondary metabolites. Secondary metabolites and those involved enzymes accumulate in various compartments in specific plant tissues. The biosynthesis of diverse groups of secondary metabolites is often complicated, tightly controlled via network interconnections, metabolite levels, metabolite channeling and multi-enzyme complexes, and so on. Secondary metabolite profiles could be genetically altered by two strategies, i.e. single gene modification and multiple gene modification; which thus has opened a feasible and prospective platform for secondary chemicals production in plant.
Gene Expression Regulation, Plant ; Phytochemicals ; biosynthesis ; genetics ; Plants ; genetics ; metabolism ; Plants, Genetically Modified ; genetics ; metabolism ; Secondary Metabolism ; genetics ; Transformation, Genetic

Plant can produce reactive oxygen species (ROS) in normal physiological activity. However, ROS can increase dramatically by environmental stress. The increase may break the ROS balance in the plant. To control ROS levels in plants, an antioxidant system is needed to protect the cell. This paper introduced the types and functions of antioxidant enzymes, and studied the effects of plant and environmental factors on the activities of antioxidant enzymes. At last, the paper discussed the research hot fields of the effect of environmental stress on antioxidant enzymes, and gave the research strategies to the problems which happened in the studies.
Antioxidants ; metabolism ; Ecosystem ; Oxidative Stress ; Plant Proteins ; metabolism ; Plants ; enzymology ; metabolism ; Reactive Oxygen Species ; metabolism