De novo transcriptome assembly and population genetic analyses of an important coastal shrub, Apocynum venetum L.

BACKGROUND: Apocynum venetum L. is an important medicinal plant that is mainly distributed in the coastal areas and northwest of China. In addition to its high medical and economic value, its adaptation to saline-alkali and coastal saline lands makes A. venetum an ideal candidate for use in vegetation restoration. To date, the study of A. venetum has been limited in the northwest region of China, little attention has been paid to the genetic diversity and population structure of A. venetum populations in the coastal region. Here, we performed transcriptome sequencing of total RNA from A. venetum leaves and developed efficient expressed sequence tag-simple sequence repeat (EST-SSR) markers for analyzing the genetic diversity and population structure of A. venetum in the coastal region. RESULTS: A total of 86,890 unigenes were generated after de novo assembly, and 68,751 of which were successfully annotated by searching against seven protein databases. Furthermore, 14,072 EST-SSR loci were detected and 10,243 primer pairs were successfully designed from these loci. One hundred primer pairs were randomly selected and synthesized, twelve primer pairs were identified as highly polymorphic and further used for population genetic analysis. Population genetic analyses showed that A. venetum exhibited low level of genetic diversity (mean alleles per locus, NA = 3.3; mean expected heterozygosity, HE = 0.342) and moderate level of genetic differentiation among the populations (genetic differentiation index, FST = 0.032-0.220) in the coastal region. Although the contemporary (mean mc = 0.056) and historical (mean mh = 0.106) migration rates among the six A. venetum populations were moderate, a decreasing trend over the last few generations was detected. Bayesian structure analysis clustered six populations into two major groups, and genetic bottlenecks were found to have occurred in two populations (QG, BH). CONCLUSIONS: Using novel EST-SSR markers, we evaluated the genetic variation of A. venetum in the coastal region and determined conservation priorities based on these findings. The large dataset of unigenes and SSRs identified in our study, combining samples from a broader range, will support further research on the conservation and evolution of this important coastal plant and its related species.

Screening and analysis of metabolites in rat urine after oral administration of Apocynum venetum L. extracts using HPLC-TOF-MS.

HPLC with diode array detection and ESI-TOF-MS was used for the study of the constituents in Apocynum venetum L. extracts and the metabolites in rat urine after oral administration of A. venetum L. extracts. A formula database of the known constituents in A. venetum L. was established, and 21 constituents were rapidly identified by accurately matching their molecular masses with the formulae of the compounds in the database. Furthermore, 34 metabolites were detected and elucidated in the rat urine. The scientific and plausible biotransformation pathways of the flavonoid components in A. venetum L. were also proposed together with the presentation of clues for potential mechanisms of bioactivity. This specific and sensitive HPLC-ESI-TOF-MS method can be used to identify the chemical components in the extracts of A. venetum L. and their metabolites in rat urine. This method can also be used to reveal the possible metabolic mechanisms of action of the extract components in vivo.

Ethnomedical uses, phytochemistry and pharmacology of Apocynum venetum L.

ETHNOPHARMACOLOGICAL RELEVANCE: Apocynum venetum L., commonly known as Luobuma, has been widely utilized in East Asia and Southeast Asia for its medicinal properties and health benefits. Its first documented mention is found in the classic Chinese text Divine Farmer's Materia Medica from the Eastern Han Dynasty, in which it is referred to as "Zeqi." In 1977, the leaves of A. venetum were officially included in the Chinese Pharmacopoeia. The 2020 edition of the Chinese Pharmacopoeia attributes various effects to A. venetum, including liver pacification, spirit tranquilization, heat clearance, and water disinhibition. AIMS OF THE REVIEW: Despite the abundance of recent studies on A. venetum leaves, a comprehensive review of the literature that incorporates the latest research findings is lacking. The primary goal of this article is to provide researchers with a more comprehensive and detailed reference by conducting an in-depth analysis of the traditional medicinal uses, phytochemicals, and pharmacological mechanisms associated with A. venetum leaves. MATERIALS AND METHODS: This research project includes original articles published from 1957 to 2024 from various databases, including Web of Science, PubMed, and the China National Knowledge Infrastructure (CNKI). Furthermore, data from ancient Chinese herbal texts, doctoral dissertations, and master's theses were examined, encompassing a total of 89 records. RESULTS: A. venetum, which is widely utilized in traditional ethnic medicine, possesses a diverse botanical chemical composition with 371 chemical constituents, including flavonoids, terpenoids, steroids, phenylpropanoids, organic acids, polysaccharides, and volatile oils. Although the water-soluble components of A. venetum remain incompletely understood, empirical evidence and scholarly literature have demonstrated the beneficial pharmacological effects of its extracts and chemical constituents, particularly the flavonoids, which offer various effects, including cardiovascular protection, anticancer properties, antioxidant activity, and anti-inflammatory effects. CONCLUSIONS: This review presents a comprehensive review of the traditional and contemporary medicinal applications of A. venetum. These findings indicate that A. venetum is effective in treating hypertension and also shows promise in addressing hyperlipidemia, atherosclerosis, and myocardial damage. This discovery may offer novel perspectives on the prevention and management of cardiovascular diseases associated with hypertension. Additionally, the article outlines a total of 114 nonvolatile phytochemicals and 257 volatile components identified in A. venetum extract, which is a significant increase compared with the previous literature. Drawing upon published data, this paper also employs bioinformatic analysis to anticipate the potential activity of additional components. In conclusion, this article offers the most comprehensive summary to date of the traditional medicinal uses and components of A. venetum, serving as a scientific foundation for the potential expansion of its clinical application.

Polyphenol-Rich Extract of Apocynum venetum L. Leaves Protects Human Retinal Pigment Epithelial Cells against High Glucose-Induced Damage through Polyol Pathway and Autophagy.

Diabetic retinopathy (DR) is a specific microvascular problem of diabetes, which is mainly caused by hyperglycemia and may lead to rapid vision loss. Dietary polyphenols have been reported to decrease the risk of DR. Apocynum venetum L. leaves are rich in polyphenolic compounds and are popular worldwide for their health benefits as a national tea drink. Building on previous findings of antioxidant activity and aldose reductase inhibition of A. venetum, this study investigated the chemical composition of polyphenol-rich extract of A. venetum leaves (AVL) and its protective mechanism on ARPE-19 cells in hyperglycemia. Ninety-three compounds were identified from AVL by LC-MS/MS, including sixty-eight flavonoids, twenty-one organic acids, and four coumarins. AVL regulated the polyol pathway by decreasing the expression of aldose reductase and the content of sorbitol, enhancing the Na+K+-ATPase activity, and weakening intracellular oxidative stress effectively; it also could regulate the expression of autophagy-related proteins via the AMPK/mTOR/ULK1 signaling pathway to maintain intracellular homeostasis. AVL could restore the polyol pathway, inhibit oxidative stress, and maintain intracellular autophagy to protect cellular morphology and improve DR. The study reveals the phytochemical composition and protective mechanisms of AVL against DR, which could be developed as a functional food and/or candidate pharmaceutical, aiming for retina protection in diabetic retinopathy.

Apocynum venetum, a medicinal, economical and ecological plant: a review update.

Apocynum venetum L. is an important medicinal perennial rhizome plant with good ecological and economic value. Its leaves have many pharmacological effects such as anti-inflammatory, anti-depression, anti-anxiolytic, etc., while its fibers have the title of "king of wild fibers". Furthermore, it was suitable for the restoration of degraded saline soil in arid areas. An increasing studies have been published in the past years. A scientometric analysis was used to analyze the publications of Apocynum venetum L. to clearly review the pharmacology, fiber application of Apocynum venetum L. and the potential value with its similar species (Apocynum pictum Schrenk) to the environment.

Solid-state fermentation of Apocynum venetum L. by Aspergillus niger: Effect on phenolic compounds, antioxidant activities and metabolic syndrome-associated enzymes.

This study aimed to evaluate the effect of solid-state fermentation (SSF) with Aspergillus niger on the total phenolic content (TPC), the total flavonoid content (TFC), individual phenolic contents, and antioxidant and inhibitory activities against metabolic syndrome-associated enzymes in an ethanol extract from Apocynum venetum L. (AVL). TPC, TFC, and the contents of quercetin and kaempferol during SSF were 1.52-, 1.33-, 3.64-, and 2.22-fold higher than those of native AVL in the ethyl acetate (EA) subfraction of the ethanol extract. The ABTS·+, DPPH· scavenging, and inhibitory activities against α-glucosidase and pancreatic lipase were found to be highest in the EA subfraction. Fermentation significantly increased the ABTS radical cation, DPPH radical scavenging, and pancreatic lipase inhibitory activities by 1.33, 1.39, and 1.28 times, respectively. TPC showed a significantly positive correlation with antioxidant activities or inhibition against metabolic syndrome-associated enzymes. This study provides a theoretical basis for producing tea products with enhanced antioxidant, antidiabetic, and antihyperlipidemic activities.

Structural characterization and immunoregulatory activity of a neutral polysaccharide from the roots of Apocynum venetum L.

The structural characteristics and immunoregulatory activities of neutral heteropolysaccharide (AVRP-N) separated from the roots of Apocynum venetum L. were extensively investigated. The results showed that the weight average molecular mass (Mw) of AVRP-N was 6.430 × 103 Da. Moreover, the backbone is composed of natural acetylated (1 â†’ 4)-ß-D-Man and (1 â†’ 5)-α-L-Ara domains. The mannan is composed of →4)-ß-D-Manp-(1→, →4)-ß-D-Glcp-(1→, and the terminal group α-D-Galp-(1→ attached to →4,6)-ß-D-Manp-(1→ at O-6. Araban is composed of →5)-α-L-Araf-(1→; the terminal group α-L-Araf-(1→attached to→2,3,5)-α-L-Araf-(1→ at O-2, O-3 and →3,5)-α-L-Araf-(1→ at O-3. In addition, the senior structure shows that AVRP-N has a triple-helix conformation. Furthermore, AVRP-N exhibited immunomodulatory effects, which could significantly regulate the proliferation of mouse splenic lymphocytes by enhancing the secretion of the cytokines (IFN-γ, IL-2, IL-4, and IL-10). Our results provide new structural and immunoregulatory information for natural polysaccharides derived from Apocynum venetum L.

Comparison of the phenolic content and antioxidant activities of Apocynum venetum L. (Luo-Bu-Ma) and two of its alternative species.

The leaves of Apocynum venetum L. (AV), a native Chinese plant, have been used as folk medicine in China and Japan. This study evaluated the content of the active antioxidant component and antioxidant activities of AV, and its two alternative species, Poacynum pictum (Schrenk) Baill. (PP) and Poacynum hendersonii (Hook.f.) Woodson (PH). The total phenolic and total flavonoid contents were determined. In addition, the quantitative analysis of two major flavonoid compounds (hyperoside and isoquercitrin) was carried out by HPLC. The antioxidant activities were investigated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity method, the reducing power test and the chelating ability of ferrous ions. The highest total phenolic and flavonoid contents were observed in the AV methanolic extract, followed by the PP and PH methanolic extracts. HPLC analysis indicated that isoquercitrin was one of the major components in all three species, however, hyperoside was only detected in AV at high levels. All the antioxidant assays we performed demonstrated that the AV extract was markedly superior to those of the other two species.

Salt stress decreases seedling growth and development but increases quercetin and kaempferol content in Apocynum venetum.

Apocynum venetum L. is a traditional Chinese medicinal herb with great potential to treat angiocardiopathy. Its major medicinal constituents are flavonoids. However, the natural habitats of A. venetum are typically affected by salt stress, which can modify both biomass and accumulation of medicinal compounds. In this study, the effects of salt stress on growth and development of A. venetum, accumulation of flavonoids and expression patterns of genes involved in flavonoid biosynthesis were evaluated. In general, the growth and development of seedlings (seedling height, root length, leaf length, leaf width and seed germination) were inhibited by salt stress. Unlike typical halophytes, there was no optimal NaCl concentration range that promoted growth and development, but seedlings had an elevated DW/FW ratio under salt stress (induced by irrigation with 50, 100, 200 or 400 mm NaCl). Furthermore, quercetin and kaempferol were significantly accumulated in A. venetum seedlings under salt stress, resulting in a balanced content and reduced FW. Moreover, the expression of AvCHS, AvCHI and AvF3GT was inhibited by salt stress; however, AvF3'H, AvF3H and AvFLS, which are involved in the flavonol synthesis pathway, were up-regulated under salt stress, consistent with a decrease in total flavonoids and an increase of flavonols (quercetin and kaempferol). In summary, cultivation of A. venetum in saline soils appeared to be feasible and improved the medicinal quality of A. venetum (quercetin and kaempferol accumulation under salt stress), thus this species can effectively utilize saline soil resources.

Anti-inflammatory properties of uvaol on DSS-induced colitis and LPS-stimulated macrophages.

BACKGROUND: Apocynum venetum leaves are used as a kind of phytomedicine and the main ingredient in some traditional Chinese medicine products for the relief of colitis. To understand the bioactive constituents of A. venetum L., we did a phytochemistry study and investigated anti-Inflammatory effects of compounds and explored the underlying mechanisms. METHODS: We isolated compounds from ethanol extract of A. venetum L. leaf and detected the most effective compound by NO inhibition assay. We investigated anti-Inflammatory effects on dextran sulfate sodium (DSS)-induced colitis mice and lipopolysaccharide (LPS)-stimulated RAW264.7 cells. The disease activity index was determined by scores of body weight loss, diarrhea and rectal bleeding; histological damage was analyzed by H&E staining; macrophages change in the colon were analyzed by immunohistochemistry (IHC); myeloperoxidase activity was measured by myeloperoxidase assay kits; levels of proinflammatory cytokines were determined by qPCR and ELISA; protein production such as COX-2, iNOS, STAT3 and ERK1/2 were determined by western blotting. RESULTS: We isolated uvaol from ethanol extract of A. venetum L. leaf and found uvaol has excellent potential of inhibiting NO production. We further found uvaol could attenuate disease activity index (DAI), colon shortening, colon injury, and colonic myeloperoxidase activity in DSS-induced colitis mice. Moreover, uvaol significantly reduces mRNA expression and production of pro-inflammatory cytokines (TNF-α, IL-6, IL-1ß, and MCP-1) and infiltration of macrophages in colonic tissues of colitis mice. Studies on LPS challenged murine macrophage RAW246.7 cells also revealed that uvaol reduces mRNA expression and production of pro-inflammatory cytokines and mediators. Mechanically, uvaol inhibits the pro-inflammatory ERK/STAT3 axis in both inflamed colonic tissues and macrophages. CONCLUSIONS: A. venetum leaf contains uvaol and uvaol has potent anti-inflammatory effects on DSS-induced experimental colitis and LPS-stimulated RAW264.7 macrophage cells. These results suggest uvaol is a prospective anti-inflammatory agent for colonic inflammation.

Anticoagulant activity of two novel polysaccharides from flowers of Apocynum venetum L.

Two novel polysaccharides were obtained from flowers of Apocynum venetum L., and named as Vp2a-II and Vp3. Their average molecular weights were 7 kDa and 9 kDa, respectively. Methods of monosaccharide analysis, acid hydrolysis and methylation analysis, Fourier transform-infrared spectroscopy (FT-IR), gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) spectroscopy were used to identify the structure of Vp2a-II and Vp3. Vp2a-II was composed of →6)-ß-d-Glcp-(1 → 6)-α-d-Galp-(1→ residues. Vp3 was composed of α-d-GlcpA-(3 → α-d-GalpA residues. The anticoagulant activity was evaluated by activated partial thromboplastin time (APTT), thrombin time (TT), prothrombin time (PT), and fibrinogen (FIB) assays in vitro. Results indicated that Vp3 exhibited the anticoagulant activity.

Protective effect of the total flavonoids from Apocynum venetum L. on carbon tetrachloride-induced hepatotoxicity in vitro and in vivo.

Apocynum venetum L., belonging to the family Apocynaceae, is a popular medicinal plant, which is commonly used in the treatment of hypertension, neurasthenia, and hepatitis in China. In the present study, the total flavonoids (TFs) were prepared from the leaves of A. venetum, and its protective effects on carbon tetrachloride (CCl4)-induced hepatotoxicity in a cultured HepG2 cell line and in mice were investigated. Cell exposed to 0.4% CCl4 (v/v) for 6 h led to a significant decrease in cell viability, increased LDH leakage, and intracellular reactive oxygen species (ROS). CCl4 also induced cell marked apoptosis, which was accompanied by the loss of mitochondrial membrane potential (MMP). Pretreatment with TFs at concentrations of 25, 50, and 100 µg/mL effectively relieved CCl4-induced cellular damage in a dose-dependent manner. In vivo, TFs (100, 200, and 400 mg/kg BW) were administered via gavage daily for 14 days before CCl4 treatment. The high serum ALT and AST levels induced by CCl4 were dose-dependently suppressed by pretreatment of TFs (200 and 400 mg/kg BW). Histological analysis also supported the results obtained from serum assays. Furthermore, TFs could prevent CCl4-caused oxidative damage by decreasing the MDA formation and increasing antioxidant enzymes (CAT, SOD, GSH-Px) activities in liver tissues. In summary, both in vitro and in vivo data suggest that TFs, prepared from A. venetum, showed a remarkable hepatoprotective and antioxidant activity against CCl4-induced liver damage.

Chemopreventive Potential of Ethanolic Extracts of Luobuma Leaves (Apocynum venetum L.) in Androgen Insensitive Prostate Cancer.

Luobuma (Apocynum venetum L. (AVL)) is a popular beverage in Asia and has been reportedly to be associated with the bioactivities such as cardiotonic, diuretic, antioxidative, and antihypertensive. However, its biofunction as chemoprevention activity is seldom addressed. Herein, we aimed to characterize the anti-androgen-insensitive-prostate-cancer (anti-AIPC) bioactive compounds of Luobuma, and to investigate the associated molecular mechanisms. Activity-guided-fractionation (antioxidative activity and cell survivability) of Luobuma ethanolic extracts was performed to isolate and characterize the major bioactive compounds using Ultra Performance Liquid Chromatography (UPLC), Liquid Chromatography-Mass Spectrometry (LC-MS), and Nuclear Magnetic Resonance (NMR). Plant sterols (lupeol, stigamasterol and ß-sitosterol) and polyphenolics (isorhamnetin, kaempferol, and quercetin) were identified. Lupeol, a triterpene found in the fraction (F8) eluted by 10% ethyl acetate/90% hexane and accounted for 19.3% (w/w) of F8, inhibited the proliferation of PC3 cells. Both lupeol and F8 induced G2/M arrest, inhibition of ß-catenin signaling, regulation of apoptotic signal molecules (cytochrome c, Bcl-2, P53, and caspase 3 and 8), and suppression DNA repair enzyme expression (Uracil-DNA glycosylase (UNG)). To our knowledge, our study is the first report that lupeol inhibited the expression of UNG to elicit the cytotoxicity against androgen-insensitive-prostate-cancer cells. Collectively, Luobuma, which contains several antitumor bioactive compounds, holds the potential to be a dietary chemopreventive agent for prostate cancer.

Anti-platelet aggregation activities of different fractions in leaves of Apocynum venetum L.

UNLABELLED: Ethnopharmacological relevance Apocynum venetum: is widely used in Uygur and traditional Chinese medicine. Modern pharmaceutical studies have shown that leaves of A. venetum have effects of liver protection, antidepressant and regulation of blood pressure. However, it is unclear that which components have pharmacological activities. AIM OF THE STUDY: The aim was to study chemical constituents of A. venetum and its anti-platelet aggregation activity. MATERIALS AND METHODS: Nephelometery was applied to evaluate anti-platelet aggregation activity of multi-components of A. venetum. Systematic separation components were characterized by HPLC analysis method, and in vitro screening active components by anti-platelet aggregation study. RESULTS: Ethyl acetate fraction (L-III) and L-III-4 have better anti-platelet aggregation activity than other fractions. The results indicated that isoquercitrin, hyperoside and other flavonoids have anti-platelet aggregation activity in A. venetum. CONCLUSION: Our studies provide basis on the endeavors of screening chemicals with that anti-platelet aggregation activity in leaves of A. venetum.

Discrimination between Leave of Apocynum venetum and Its Adulterant, A. pictum Based on Antioxidant Assay and Chemical Profiles Combined with Multivariate Statistical Analysis.

An integrated approach including chemical and biological assessments was developed to investigate the differences between Apocynum venetum L. (AV) and its adulterant, Apocynum pictum Schrenk (AP). Ten flavonoids were tentatively identified by ultra-visible and mass spectra data. The chemical component, hyperoside, was identified as a critical parameter for discrimination of two species from the results of principal component analysis (PCA) and quantitative analysis. The anti-oxidative power of the herbal extracts were determined using 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH) assay and H2O2-induced cell damage on LO2 cells. The results of the biological assays suggested that the chemical differences between AV and AP do lead to difference in activity and AV is demonstrated to have higher anti-oxidant activity.

Simultaneous qualitative and quantitative analysis of phenolic acids and flavonoids for the quality control of Apocynum venetum L. leaves by HPLC-DAD-ESI-IT-TOF-MS and HPLC-DAD.

A reliable method based on high performance liquid chromatography-diode array detector-electrospray ionization-ion trap-time of flight-mass spectrometry (HPLC-DAD-ESI-IT-TOF-MS) was developed for the identification of phenolic acids and flavonoids in Apocynum venetum L. leaves and its adulterant, Pocynum hendersonii (Hook. f.) Woodson leaves. A total of 21 compounds were identified or tentatively identified, including 4 phenolic acids and 17 flavonoids. 3-O-caffeoylquinic acid (3-CQA) and caffeic acid were detected for the first time in A. venetum leaves; 4-O-caffeoylquinic acid (4-CQA), 3-CQA, caffeic acid, quercetin-3-O-(6"-O-malonyl)-galactoside, quercetin-3-O-(6"-O-malonyl)-glucoside, kaempferol-3-O-(6"-O-malonyl)-glucoside, kaempferol-3-O-(6"-O-acetyl)-glucoside, and kaempferol-3-O-dihexoside were detected for the first time in P. hendersonii leaves. Cluster analysis was employed to analyze 24 batches of A. venetum leaves and 5 batches of P. hendersonii leaves collected from various regions in China. The analysis, which was based on the 21 compounds, indicated that profiles of these compounds were distinct between the two species, and among A. venetum leaf samples from different origins. 18 of these 21 compounds were selected as the markers and simultaneously analyzed by HPLC-DAD for the first time. The quantitative analytical method was validated and subsequently applied to the comprehensive quality evaluation of 24 batches of A. venetum leaves.