Quality parameters for the medicinal plant Drosera rotundifolia L.: A new approach with established techniques.

Monographs of the European Pharmacopoeia (Ph. Eur.) are the basis for quality control of medicinal plants and therefore important to ensure the consistency, quality, safety, and efficacy of phytopharmaceuticals. The traditional medicinal plant sundew (Drosera sp.) has disappeared from therapy due to nature conservation, but can now be cultivated sustainably on rewetted peatland. However, currently there is no valid Ph. Eur. monograph for the quality control of Droserae herba. In this study, sundew material from different species and sources was investigated with the aim of developing quality control methods based on the Ph. Eur. and defining a uniform quality standard for Droserae herba. It was possible to distinguish between sundew species of different quality, using macroscopic, microscopic, and chromatographic methods. Special emphasis was laid on the content of flavonoids and naphthoquinones as important quality parameters as their content differed between the sundew species. The differences in content and toxicity result in the recommendation that only round-leaved sundew (Drosera rotundifolia L.) should be used as a medicinal plant for the production of phytopharmaceuticals in the future.

Microwave Radiation as an Inducer of Secondary Metabolite Production in Drosera rotundifolia In Vitro Plantlets.

In this study, low-intensity microwave irradiation (frequency of 2.45 GHz; 26.3 kW m-3 power density) for 0, 5, and 30 s was tested for the first time on Drosera rotundifolia in vitro plantlets to explore its effect on the production of highly valued phenolic compounds. Analysis of the extracts obtained from irradiated plantlets revealed time-dependent increases in the levels of photosynthetic pigments, particularly the carotenoids, whereas symptoms of growth decline were not observed. Similarly, the highest total antioxidant capacity and total phenolic and flavonoid contents were detected in 30-s-irradiated plantlets. High-performance liquid chromatography analysis revealed that the content of the bioactive phenolics 5-hydroxy-7-methylnaphthalene-1,4-dione (1), 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxychromen-4-one (2), and 2-(3,4-dihydroxyphenyl)-5,7-dihydroxy-3-[(3R,4S,5R,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxychromen-4-one (3), which are considered to be responsible for the pharmacological properties of this species, was around twofold higher in 30-s-irradiated plantlets than in controls. Nevertheless, the accumulation of 5-hydroxy-2-methylnaphthalene-1,4-dione (4), which was present only in trace amounts in the plant roots, decreased by 30% upon microwave irradiation. The results indicate that microwave treatment acts as an effective inducer of the production of phenylpropanoid compounds, which opens up new opportunities for its use in biotechnological applications.

Field-Grown and In Vitro Propagated Round-Leaved Sundew (Drosera rotundifolia L.) Show Differences in Metabolic Profiles and Biological Activities.

Drosera rotundifolia L. is a carnivorous plant used in traditional medicine for its therapeutic properties. Because of its small size, its collection in nature is laborious and different cultivation methods have been studied to ensure availability. However, only a few studies exist where the lab-grown sundew tissue and field-grown sundew would have been compared in their functionality or metabolic profiles. In this study, the antioxidant and antiviral activities of lab-grown and field-grown sundew extracts and their metabolic profiles are examined. The effect of drying methods on the chromatographic profile of the extracts is also shown. Antioxidant activity was significantly higher (5-6 times) in field-grown sundew but antiviral activity against enterovirus strains coxsackievirus A9 and B3 was similar in higher extract concentrations (cell viability ca. 90%). Metabolic profiles showed that the majority of the identified compounds were the same but field-grown sundew contained higher numbers and amounts of secondary metabolites. Freeze-drying, herbal dryer, and oven or room temperature drying of the extract significantly decreased the metabolite content from -72% up to -100%. Freezing was the best option to preserve the metabolic composition of the sundew extract. In conclusion, when accurately handled, the lab-grown sundew possesses promising antiviral properties, but the secondary metabolite content needs to be higher for it to be considered as a good alternative for the field-grown sundew.

Phytochemical Profiling and Biological Activity of the Australian Carnivorous Plant, Drosera magna.

Phytochemical profiling was undertaken on the crude extracts of Drosera magna to determine the nature of the chemical constituents present. In total, three new flavonol diglycosides (1-3), one new flavan-3-ol glycoside (4), and 12 previously reported compounds of the flavonol (5, 9), flavan-3-ol (15), flavanone (8), 1,4-napthoquinone (6, 7, 13, 14), 2,3-dehydroxynapthalene-1,4-dione (10-12), and phenolic acid (16) structure classes were isolated and identified. Compounds 1-9, 13, 17, and 18 were assessed for antimicrobial activity, with compounds 6, 7, 8, and 9 showing significant activity. Compounds 1, 2, and 6 were also evaluated for anthelmintic activity against larval forms of Hemonchus contortus, with compound 6 being active.

Low-dose Drosera rotundifolia induces gene expression changes in 16HBE human bronchial epithelial cells.

Drosera rotundifolia has been traditionally used for the treatment of respiratory diseases in phytotherapy and homeopathy. The mechanisms of action recognized so far are linked to the known effects of specific components, such as flavonoids, but are not completely understood. In this study, the biological functions of D. rotundifolia were explored in vitro following the treatment of bronchial epithelial cells, which are the potential targets of the pharmacological effects of the herbal medicine. To do so, the whole plant ethanolic extract was 1000-fold diluted in water (D. rotundifolia 3×) and added to a 16HBE human cell line culture for 3 h or 6 h. The effects on gene expression of the treatments and corresponding controls were then investigated by RNA sequencing. The differentially expressed genes were validated through RT-qPCR, and the enriched biological functions involved in the effects of treatment were investigated. D. rotundifolia 3× did not impair cell viability and was shown to be a stimulant of cell functions by regulating the expression of dozens of genes after 3 h, and the effects were amplified after 6 h of treatment. The main differentially expressed genes encoded ligands of epithelial growth factor receptor, proteins involved in xenobiotic detoxification and cytokines, suggesting that D. rotundifolia 3× could stimulate self-repair systems, which are impaired in airway diseases. Furthermore, D. rotundifolia 3× acts on a complex and multifaceted set of genes and may potentially affect different layers of the bronchial mucosa.

Drosera tokaiensis extract containing multiple phenolic compounds inhibits the formation of advanced glycation end-products.

The accumulation of advanced glycation end-products (AGEs) correlates with aging and accompanies the onset of age-related diseases, such as diabetes and arteriosclerosis. Therefore, a daily intake of natural compounds that inhibit the production of AGEs may be beneficial in preventing these diseases. In this study, we evaluated the inhibitory effects of 14 natural crude extracts, including those of Drosera species, which possess anti-inflammatory activity, on the formation of AGEs, such as Nω-(carboxymethyl)arginine (CMA) and Nε-(carboxymethyl)lysine (CML). Crude extracts of Drosera inhibited the formation of CMA and CML by incubation on gelatin with ribose more effectively than with other extracts, so active compounds that prevent AGE formation were purified from Drosera tokaiensis, which is endemic to Japan. Several compounds were purified from D. tokaiensis extracts using HPLC and identified by NMR analysis. These compounds included ellagic acid, 3,3'-di-O-methylellagic acid 4'-glucoside, myricitrine, and quercimelin. Furthermore, all compounds showed a significantly higher inhibitory effect on CMA and CML formations than aminoguanidine. Specifically, ellagic acid and myricitrine had the highest inhibitory effects of the compounds tested. However, not all compounds showed inhibition of CMA formation in a mixture of gelatin and glyoxal (GO). These results suggest that the compounds in D. tokaiensis inhibit CMA and CML formations via the antioxidative activity of phenolic compounds, rather than GO trapping action. This study provides the first evidence that D. tokaiensis inhibits CMA and CML formations and that phenolic compounds such as ellagic acid and myricitrine play an important role as active components of D. tokaiensis extracts.

The Droserasin 1 PSI: A Membrane-Interacting Antimicrobial Peptide from the Carnivorous Plant Drosera capensis.

The Droserasins, aspartic proteases from the carnivorous plant Drosera capensis, contain a 100-residue plant-specific insert (PSI) that is post-translationally cleaved and independently acts as an antimicrobial peptide. PSIs are of interest not only for their inhibition of microbial growth, but also because they modify the size of lipid vesicles and strongly interact with biological membranes. PSIs may therefore be useful for modulating lipid systems in NMR studies of membrane proteins. Here we present the expression and biophysical characterization of the Droserasin 1 PSI (D1 PSI.) This peptide is monomeric in solution and maintains its primarily α -helical secondary structure over a wide range of temperatures and pH values, even under conditions where its three disulfide bonds are reduced. Vesicle fusion assays indicate that the D1 PSI strongly interacts with bacterial and fungal lipids at pH 5 and lower, consistent with the physiological pH of D. capensis mucilage. It binds lipids with a variety of head groups, highlighting its versatility as a potential stabilizer for lipid nanodiscs. Solid-state NMR spectra collected at a field strength of 36 T, using a unique series-connected hybrid magnet, indicate that the peptide is folded and strongly bound to the membrane. Molecular dynamics simulations indicate that the peptide is stable as either a monomer or a dimer in a lipid bilayer. Both the monomer and the dimer allow the passage of water through the membrane, albeit at different rates.

Effect of 3-O-acetylaleuritolic acid from in vitro-cultured Drosera spatulata on cancer cells survival and migration.

BACKGROUND: Drosera spatulata is a source of many compounds such as naphthoquinones, phenolic acids, flavonoids, anthocyanins, and naphthalene derivatives. Unfortunately, the information regarding the biological activity and chemical profile of those compounds is still incomplete. Herein, we investigated the biological activity of 3-O-acetylaleuritolic acid (3-O-AAA) in cancer cell lines. METHODS: The cell viability of HeLa, HT-29, MCF7, and MCF12A cells was assessed using MTT assay. Proliferation potential was assessed using the clonogenic assay and flow cytometry. Migration modulation was tested using a scratch assay. Protein expression was analyzed by immunoblotting. RESULTS: 3-O-AAA significantly inhibited the growth of all tested tumor cells. The results of the colony formation assay suggested cytostatic properties of the studied compound. The scratch assay showed that 3-O-AAA was an efficient migration inhibitor in a dose-dependent manner. Moreover, it caused modulation of mTOR, beclin1, and Atg5 proteins suggesting a possible role of the compound in autophagy induction. CONCLUSION: Collectively, these results demonstrated that 3-O-AAA inhibited the proliferation and migration of cancer cell lines as well as contributed to autophagy induction showing some anticancer properties.

Composite Nanostructures and Adhesion Analysis of Natural Plant Hydrogels Investigated by Atomic Force Microscopy.

Hydrogels designed by biomimetism and bioinspiration have been considered as a promising biomaterial for biomedical applications due to their biocompatible characteristics. Though biomimetic or bioinspired hydrogels have been widely studied by biochemical analysis, so far the detailed organizations and properties of native natural hydrogels are still not fully understood. The advent of atomic force microscopy (AFM) provides a potent tool for probing the biological samples in their living states with nanometer spatial resolution, which offers new possibilities for addressing the biological and material issues at the nanoscale. In this paper, AFM was utilized to characterize the structures and adhesive properties of the natural hydrogels produced by the carnivorous plant sundew. AFM morphological images of the mucilage secreted by three types of sundew show the composite nanostructures of the mucilage (e.g., nanoparticles, nanofibers, and porous polymeric networks), which are correlated with the mucilage's adhesive features revealed by AFM force measurements and peak force tapping mechanical imaging. The research demonstrates the prominent capabilities of AFM in characterizing the nanoscopic structures and properties of natural hydrogels with unprecedented spatial resolution, which is useful for understanding the underlying mechanisms guiding the behaviors of natural hydrogels and will potentially benefit the studies of biomimetic and bioinspired biomaterials.

Efficacy and tolerability of a complex homeopathic drug in children suffering from dry cough-A double-blind, placebo-controlled, clinical trial.

BACKGROUND: A randomised, placebo-controlled clinical trial in children suffering from acute dry cough was performed to assess the efficacy and tolerability of a complex homeopathic drug (Drosera, Coccus cacti, Cuprum Sulfuricum, Ipecacuanha=Monapax syrup, short: verum). METHODS: 89 children received verum and 91 received placebo daily for 7 days (age groups 0.5-3, 4-7 and 8-12 years). The primary efficacy variable was the improvement of the Cough Assessment Score. Tolerability and compliance were also assessed. A confirmatory statistical analysis was performed for the primary efficacy variable and a descriptive analysis for the secondary parameters. RESULTS: The Cough Assessment Score showed an improvement of 5.2±2.6 points for children treated with verum and 3.2±2.6 points in the placebo group (p<0.0001). The difference of the least square means of the improvements was 1.9±0.4. The effect size of Cohen´s d was d=0.77. In all secondary parameters the patients in the verum group showed higher rates of improvement and remission than those in the placebo group. In 15 patients (verum: n=6; placebo: n=9) 18 adverse drug reactions of mild or moderate intensity were observed. CONCLUSIONS: Administering verum resulted in a statistically significantly greater improvement of the Cough Assessment Score than the placebo. The tolerability was good and not inferior to that of the placebo.

Ramentaceone, a Naphthoquinone Derived from Drosera sp., Induces Apoptosis by Suppressing PI3K/Akt Signaling in Breast Cancer Cells.

The phosphoinositide 3-kinase (PI3K) signaling pathway plays an important role in processes critical for breast cancer progression and its upregulation confers increased resistance of cancer cells to chemotherapy and radiation. The present study aimed at determining the activity of ramentaceone, a constituent of species in the plant genera Drosera, toward breast cancer cells and defining the involvement of PI3K/Akt inhibition in ramentaceone-mediated cell death induction. The results showed that ramentaceone exhibited high antiproliferative activity toward breast cancer cells, in particular HER2-overexpressing breast cancer cells. The mode of cell death induced by ramentaceone was through apoptosis as determined by cytometric analysis of caspase activity and Annexin V staining. Apoptosis induction was found to be mediated by inhibition of PI3K/Akt signaling and through targeting its downstream anti-apoptotic effectors. Ramentaceone inhibited PI3-kinase activity, reduced the expression of the PI3K protein and inhibited the phosphorylation of the Akt protein in breast cancer cells. The expression of the anti-apoptotic Bcl-2 protein was decreased and the levels of the pro-apoptotic proteins, Bax and Bak, were elevated. Moreover, inhibition of PI3K and silencing of Akt expression increased the sensitivity of cells to ramentaceone-induced apoptosis. In conclusion, our results indicate that ramentaceone induces apoptosis in breast cancer cells through PI3K/Akt signaling inhibition. These findings suggest further investigation of ramentaceone as a potential therapeutic agent in breast cancer therapy, in particular HER2-positive breast cancer.

Sundew-Inspired Adhesive Hydrogels Combined with Adipose-Derived Stem Cells for Wound Healing.

The potential to harness the unique physical, chemical, and biological properties of the sundew (Drosera) plant's adhesive hydrogels has long intrigued researchers searching for novel wound-healing applications. However, the ability to collect sufficient quantities of the sundew plant's adhesive hydrogels is problematic and has eclipsed their therapeutic promise. Inspired by these natural hydrogels, we asked if sundew-inspired adhesive hydrogels could overcome the drawbacks associated with natural sundew hydrogels and be used in combination with stem-cell-based therapy to enhance wound-healing therapeutics. Using a bioinspired approach, we synthesized adhesive hydrogels comprised of sodium alginate, gum arabic, and calcium ions to mimic the properties of the natural sundew-derived adhesive hydrogels. We then characterized and showed that these sundew-inspired hydrogels promote wound healing through their superior adhesive strength, nanostructure, and resistance to shearing when compared to other hydrogels in vitro. In vivo, sundew-inspired hydrogels promoted a "suturing" effect to wound sites, which was demonstrated by enhanced wound closure following topical application of the hydrogels. In combination with mouse adipose-derived stem cells (ADSCs) and compared to other therapeutic biomaterials, the sundew-inspired hydrogels demonstrated superior wound-healing capabilities. Collectively, our studies show that sundew-inspired hydrogels contain ideal properties that promote wound healing and suggest that sundew-inspired-ADSCs combination therapy is an efficacious approach for treating wounds without eliciting noticeable toxicity or inflammation.

Flavonoids as chemotaxonomic markers in the genus Drosera.

The botanical classification of the huge genus Drosera remains controversial since long. In the present study, the pattern of major phenolic compounds in ten Drosera species belonging to seven different subgenera and/or sections of the genus was investigated for chemotaxonomic allocation. The composition of flavonoids and ellagic acid derivatives in Drosera adelae, Drosera burmannii, Drosera dielsiana, Drosera hilaris, Drosera montana, Drosera petiolaris, and Drosera pygmaea was elucidated for the first time. The scarce data on these compounds in Drosera binata, Drosera aliciae, and Drosera spatulata were complemented significantly. Detailed LC-DAD-MS, LC-NMR, and offline 1D and 2D NMR analyses resulted in the unambiguous identification of around 40 different substances, three of them (8-hydroxy-luteolin-8-O-arabinopyranoside, tricetin-7-O-xylopyranoside and 8-hydroxytricetin-8-O-arabinopyranoside) being natural products described for the first time. The distribution of the compounds characterized underlines their potential to serve as chemotaxonomic markers in this genus.

Functional analyses of carnivorous plant-specific amino acid residues in S-like ribonucleases.

Unlike plants with no carnivory, carnivorous plants seem to use S-like ribonucleases (RNases) as an enzyme for carnivory. Carnivorous plant-specific conserved amino acid residues are present at four positions around the conserved active site (CAS). The roles of these conserved amino acid residues in the enzymatic function were explored in the current study by preparing five recombinant variants of DA-I, the S-like RNase of Drosera adelae. The kcat and kcat/Km values of the enzymes revealed that among the four variants with a single mutation, the serine to glycine mutation at position 111 most negatively influenced the enzymatic activity. The change in the bulkiness of the amino acid residue side-chain seemed to be the major cause of the above effect. Modeling of the three dimensional (3D) structures strongly suggested that the S to G mutation at 111 greatly altered the overall enzyme conformation. The conserved four amino acid residues are likely to function in keeping the two histidine residues, which are essential for the cleavage of RNA strands, and the CAS in the most functional enzymatic conformation.

An Antioxidant Extract of the Insectivorous Plant Drosera burmannii Vahl. Alleviates Iron-Induced Oxidative Stress and Hepatic Injury in Mice.

Free iron typically leads to the formation of excess free radicals, and additional iron deposition in the liver contributes to the oxidative pathologic processes of liver disease. Many pharmacological properties of the insectivorous plant Drosera burmannii Vahl. have been reported in previous studies; however, there is no evidence of its antioxidant or hepatoprotective potential against iron overload. The antioxidant activity of 70% methanolic extract of D. burmannii (DBME) was evaluated. DBME showed excellent DPPH, hydroxyl, hypochlorous, superoxide, singlet oxygen, nitric oxide, peroxynitrite radical and hydrogen peroxide scavenging activity. A substantial iron chelation (IC50 = 40.90 ± 0.31 µg/ml) and supercoiled DNA protection ([P]50 = 50.41 ± 0.55 µg) were observed. DBME also displayed excellent in vivo hepatoprotective activity in iron-overloaded Swiss albino mice compared to the standard desirox treatment. Administration of DBME significantly normalized serum enzyme levels and restored liver antioxidant enzymes levels. DBME lowered the raised levels of liver damage parameters, also reflected from the morphological analysis of the liver sections. DBME also reduced liver iron content by 115.90% which is also seen by Perls' staining. A phytochemical analysis of DBME confirms the presence of various phytoconstituents, including phenols, flavonoids, carbohydrates, tannins, alkaloids and ascorbic acid. Alkaloids, phenols and flavonoids were abundantly found in DBME. An HPLC analysis of DBME revealed the presence of purpurin, catechin, tannic acid, reserpine, methyl gallate and rutin. Purpurin, tannic acid, methyl gallate and rutin displayed excellent iron chelation but exhibited cytotoxicity toward normal (WI-38) cells; while DBME found to be non-toxic to the normal cells. These findings suggest that the constituents present in DBME contributed to its iron chelation activity. Additional studies are needed to determine if DBME can be used as a treatment for iron overload diseases.

Sundew adhesive: a naturally occurring hydrogel.

Bioadhesives have drawn increasing interest in recent years, owing to their eco-friendly, biocompatible and biodegradable nature. As a typical bioadhesive, sticky exudate observed on the stalked glands of sundew plants aids in the capture of insects and this viscoelastic adhesive has triggered extensive interests in revealing the implied adhesion mechanisms. Despite the significant progress that has been made, the structural traits of the sundew adhesive, especially the morphological characteristics in nanoscale, which may give rise to the viscous and elastic properties of this mucilage, remain unclear. Here, we show that the sundew adhesive is a naturally occurring hydrogel, consisting of nano-network architectures assembled with polysaccharides. The assembly process of the polysaccharides in this hydrogel is proposed to be driven by electrostatic interactions mediated with divalent cations. Negatively charged nanoparticles, with an average diameter of 231.9 ± 14.8 nm, are also obtained from this hydrogel and these nanoparticles are presumed to exert vital roles in the assembly of the nano-networks. Further characterization via atomic force microscopy indicates that the stretching deformation of the sundew adhesive is associated with the flexibility of its fibrous architectures. It is also observed that the adhesion strength of the sundew adhesive is susceptible to low temperatures. Both elasticity and adhesion strength of the sundew adhesive reduce in response to lowering the ambient temperature. The feasibility of applying sundew adhesive for tissue engineering is subsequently explored in this study. Results show that the fibrous scaffolds obtained from sundew adhesive are capable of increasing the adhesion of multiple types of cells, including fibroblast cells and smooth muscle cells, a property that results from the enhanced adsorption of serum proteins. In addition, in light of the weak cytotoxic activity exhibited by these scaffolds towards a variety of mammal cells, evidence is sufficient to propose that sundew adhesive is a promising nanomaterial worth further exploitation in the field of tissue engineering.

Nitrogen deposition and prey nitrogen uptake control the nutrition of the carnivorous plant Drosera rotundifolia.

Nitrogen (N) deposition has important negative impacts on natural and semi-natural ecosystems, impacting on biotic interactions across trophic levels. Low-nutrient systems are particularly sensitive to changes in N inputs and are therefore more vulnerable to N deposition. Carnivorous plants are often part of these ecosystems partly because of the additional nutrients obtained from prey. We studied the impact of N deposition on the nutrition of the carnivorous plant Drosera rotundifolia growing on 16 ombrotrophic bogs across Europe. We measured tissue N, phosphorus (P) and potassium (K) concentrations and prey and root N uptake using a natural abundance stable isotope approach. Our aim was to test the impact of N deposition on D. rotundifolia prey and root N uptake, and nutrient stoichiometry. D. rotundifolia root N uptake was strongly affected by N deposition, possibly resulting in reduced N limitation. The contribution of prey N to the N contained in D. rotundifolia ranged from 20 to 60%. N deposition reduced the maximum amount of N derived from prey, but this varied below this maximum. D. rotundifolia tissue N concentrations were a product of both root N availability and prey N uptake. Increased prey N uptake was correlated with increased tissue P concentrations indicating uptake of P from prey. N deposition therefore reduced the strength of a carnivorous plant-prey interaction, resulting in a reduction in nutrient transfer between trophic levels. We suggest that N deposition has a negative impact on D. rotundifolia and that responses to N deposition might be strongly site specific.

Drosera peltata Smith var. lunata (Buch.-Ham.) C. B. Clarke as a feasible source of plumbagin: phytochemical analysis and antifungal activity assay.

Drosera peltata Smith var. lunata (Buch.-Ham.) C. B. Clarke (DPVL) fractions and plumbagin were tested via broth microdilution techniques on Rhizopus oryzae, Aspergillus flavus, Aspergillus niger, Aspergillus oryzae, Penicillium citrinum. All of the test substances [petroleum ether, chloroform, ethyl acetate, n-butanol fraction and aqueous residue (AR)] except for the AR were active against all the tested strains. The petroleum ether fraction (PEF) was the most active (MIC = 5.86-46.88 µg/ml, MFC = 23.44-93.75 µg/ml) of the five tested substances and therefore, was selected for further analysis. Based on antifungal activity, bioactivity-guided fractionation of the PEF led to the isolation of plumbagin. The structure of plumbagin was elucidated by ¹H and ¹³C NMR. Using HPLC, DPVL was found to be a new source of plumbagin. Reversed-phase HPLC was performed using a mobile phase of water and methanol, and peaks were detected at 254 nm. Plumbagin showed a good linear relationship at concentrations ranging from 0.625 to 10 µg/ml. Both the intraday and the interday precision showed that the method was precise, with RSDs of at least 3% at different concentrations. Recovery rates ranging from 97.86 to 99.94% were observed, which indicate that the method is accurate. The specificity of the method was established by checking the peak purity of plumbagin. For six independent measurements, the average plumbagin content in DPVL was 11.05 ± 0.31 mg/g of dried material. The validated HPLC method provides a new basis for assessing DPVL quality.

Phytochemistry of the carnivorous sundew genus Drosera (Droseraceae) - future perspectives and ethnopharmacological relevance.

Species of the carnivorous genus Drosera L. have long been a source of valuable natural products. The various phytochemicals characteristic of these species, particularly 1,4-naphthoquinones and flavonoids, have contributed to the diverse utilization of sundews in traditional medicine systems worldwide. A growing number of studies have sought to investigate the comparative phytochemistry of Drosera species for improved sources of pharmaceutically important compounds. The outcomes of these studies are here collated, with emergent trends discussed in detail. Important factors which affect production of secondary metabolites in plants are critically examined, such as environmental influences and in vitro culture, and recommendations subsequently presented based on this. Explicitly, the current review aims to i) present an updated, comprehensive listing of the phytochemical constituents of the genus (including quantitative data where available), ii) summarize important factors which may influence the production of phytopharmaceuticals in plants, and iii) recommend guidelines for future research based on the above, including improved standardization and quality control. We have also included a section discussing future perspectives of research on Drosera spp. based on three different research lines i) the potential to produce much needed lead compounds for treatment of tuberculosis, ii) the potential role of anthocyanins in nitrogen transport, and iii) research into 'Natural Deep Eutectic' solvents produced by Drosera spp. in the droplets or 'dew' employed to capture insect prey.

LC-NMR, NMR, and LC-MS identification and LC-DAD quantification of flavonoids and ellagic acid derivatives in Drosera peltata.

The herb of Drosera peltata, commonly named the shield sundew, is used as an antitussive in phytotherapy, although the plants' composition has not been determined in detail so far. Hence, in this study, we present a validated, sensitive, reliable, and cheap narrow-bore LC-DAD method for the simultaneous quantification of flavonoids and ellagic acid derivatives in this herbal drug. In addition, the structures of 13 compounds have been elucidated by LC-MS, LC-NMR, and offline NMR experiments after isolation: herbacetin-3-O-glucoside (1), gossypitrin (2), ellagic acid (3), quercetin-7-O-glucoside (4), isoquercitrin (5), kaempferol-3-O-(6″-O-galloyl)-glucoside (6), herbacetin-7-O-glucoside (7), astragalin (8), gossypetin (9), herbacetin (10), quercetin (11), 3,3'-di-O-methyl ellagic acid (12), and kaempferol (13). Compounds 1, 2, 4, 5, 6, 7, and 10 have been identified in D. peltata for the first time, and compounds 1, 4, 6, 7, and 10 have not been detected in any Drosera species before.