Drosera Species Research Articles

ACTIONS OF DROSERA SP IN DENTISTRY DISEASES. PHITOCHEMICAL COMPONENTS, PHARMACOLOGICAL ACTIONS

The aim of this review is to establish the main phytoconstituents of Drosera species and to find interrelations between them and the pharmacological action of the extracts. We paid special attention to the possibilities of using the Drosera species in the field of dentistry. To achieve the proposed goal, a series of scientific publications on the chemical composition, pharmacological action and medicinal use of Drosera species were identified and evaluated. The analysis took into account different criteria: the establishment of the phytoconstituents, the chemical methods of isolation, the analysis and the pharmacological particularities, and the use in dental field. Results showed that Drosera species are rich in flavonoids, especially flavonols (gossypin and gossiptrin) and their glycosides (quercetin, isoquercetin, hyperoside, astralgin), naphthoquinone derivatives (plumbagin, naphthoquinone) and tannins (ellagic acid, dimethylellagic acid). These components are responsible for anti-inflammatory, antispasmodic, antioxidant and anti tumoral activity. The first studies related to the anti-inflammatory action are recorded in 2002 by Kolodziej [23] and refers to Drosera peltata. The latest studies on the anti-inflammatory action are those from 2022 led by Hake [22] and these lead to a better understanding of the mechanism of the anti-inflammatory action , respectively of its natural compounds ( quercetin , isoquercetin and hyperoside ) functioning as neutrophyl inhibitors. Drosera sp. can be used in dental diseases due to the anti-inflammatory and antibacterial action of its bioactive components.

Accumulation of Polyphenols and Naphthoquinones in Morphogenic Cultures of Two Drosera Species

A rhizogenic culture of Drosera capensis L. was obtained. An HPLC method with UV and mass-spectrometric detection was applied to analyze the effect of different drying protocols on the yield of individual polyphenols and 1,4-naphthoquinones from the rhizogenic culture of D. capensis L. The results of this analysis were compared with similar data obtained on the previously established morphogenic culture of D. rotundifolia L. that has been maintained for more than 15 years. In the rhizogenic culture of D. capensis L., six compounds were identified for the first time (myricetin-3-O-β-glucopyranoside, rossoliside, 3,3'-di-O-methylellagic acid 4-O-β-D-glycopyranoside, myricetin, 3,3'-di-O-methylellagic acid, and plumbagin).

Accumulation of Polyphenols and Naphthoquinones in Morphogenic Cultures of Two Drosera Species

Accumulation of Polyphenols and Naphthoquinones in Morphogenic Cultures of Two Drosera Species

Light-emitting diode-induced ellagic acid production in Drosera tokaiensis inhibits advanced glycation end-product formation

Drosera tokaiensis (DT) is an insectivorous plant that effectively inhibits advanced glycation end products (AGEs) generated from non-enzymatic reactions between reducing sugars and protein amino groups using phenolic compounds, including ellagic acid, myricitrin, and quercitrin. The accumulation of AGEs increases during the pathogenesis of non-communicable diseases, such as diabetes and nephropathy. Therefore, the extracts of Drosera species could have preventive effects against such diseases. The development of light-emitting diodes (LEDs) and their use in plant cultivation and tissue culture can enhance secondary metabolite production by controlling the wavelength of light in which plants are cultivated. We evaluated how LEDs affected the production of AGE-inhibitory compounds in extracts isolated from DT tissue cultures. DT was cultured for two months in different light wavelengths under unified photosynthetic photon flex density and the resulting extracts were used to examine changes in phenolic compound content and the inhibition of AGE formation. Cultivation in monochromatic light from LEDs had no significant effect on plant weight compared to conventional fluorescent cultivation, except for red LED light. Ellagic acid content increased regardless of LED coloration and the production and accumulation of myricitrin and quercitrin were inhibited. The extracts isolated from plantlets cultured under LEDs showed the same level of AGE inhibition as those cultured under fluorescent light. Therefore, for anti-glycation activity, DT can be grown stably and at a low cost using LED lights when compared to conventional culture methods.

Better to risk limb than life: some insects use autotomy to escape passive predation by carnivorous plants

Limb autotomy, the voluntary shedding of body parts as a strategy to escape predation or entrapment, is particularly common in insects and other arthropods that are frequently captured by the carnivorous plant genus Drosera. However, no study has previously examined the effectiveness of autotomy at facilitating escape from these passive, sessile plant predators. Using field observations of numerous Drosera species in Western Australia and Australia’s Northern Territory, we present the first field evidence of limb autotomy being employed by insects and other arthropods to escape capture by carnivorous plants. Most autotomised limbs found on the Drosera traps belonged to large nematoceran flies, probably comprised primarily of Tipulidae (crane flies), which have a characteristically large, slender body with very long limbs that seems likely to allow the effective use of autotomy as a strategy to prevent fatal capture. However, autotomy was overall only rarely observed amongst the Drosera prey as most prey items were small and quickly became completely enveloped by the sticky mucilage, rendering any such escape attempts impossible. Finally, we determined that the likelihood of escape decreased markedly as multiple limbs were lost.

Snatching Sundews—Analysis of Tentacle Movement in Two Species of Drosera in Terms of Response Rate, Response Time, and Speed of Movement

Drosera, Droseraceae, catch prey with sticky tentacles. Both Australian Drosera allantostigma and widespread D. rotundifolia show three types of anatomically different tentacles: short, peripheral, and snap-tentacles. The latter two are capable of fast movement. This motion was analysed after mechanical, chemical, and electrical stimulation with respect to response rate, response time, and angular velocity of bending. Compared to D. rotundifolia, D. allantostigma responds more frequently and faster; the tentacles bend with higher angular velocity. Snap-tentacles have a lower response rate, shorter response time, and faster angular velocity. The response rates for chemical and electrical stimuli are similar, and higher than the rates for mechanical stimulus. The response time is not dependent on stimulus type. The higher motility in D. allantostigma indicates increased dependence on mechanical prey capture, and a reduced role of adhesive mucilage. The same tentacle types are present in both species and show similar motility patterns. The lower response rate of snap-tentacles might be a safety measure against accidental triggering, since the motion of snap-tentacles is irreversible and tissue destructive. Furthermore, tentacles seem to discern stimuli and respond specifically. The established model of stereotypical tentacle movement may not fully explain these observations.

Antibiofilm Activity of Sundew Species against Multidrug-Resistant Escherichia coli Strains.

Species of the genus Drosera, known for carnivorous plants, such as sundew, have been traditionally used for centuries as medicinal plants. Efficacy-determining compounds are naphthoquinones and flavonoids. Flavonoids possess a broad spectrum of bioactive properties, including biofilm inhibitory activity. Biofilms render antibiotics ineffective, contributing to the current rise in antimicrobial resistance. In this study, the biofilm inhibitory activity of two European sundew species (Drosera rotundifolia and Drosera intermedia) grown agriculturally in Germany and four commercial sundew products (declared as Drosera longifolia, Drosera sp. and Drosera planta trit.) against three multidrug-resistant Escherichia coli strains was tested. The aim of the study was to comparatively investigate the biofilm inhibitory potential of sundew species extracts grown locally in northern Germany and commercial sundew products. The minimum biofilm inhibitory concentration of the European sundew species was approx. 35 µg mL-1. In comparison, commercial sundew products ranged in concentration from 75 to 140 µg mL-1. Additionally, individual compounds isolated from European sundew were tested. Among these compounds, biofilm inhibitory activity was determined for four of the eight substances, with 2″-O-galloyl hyperoside standing out for its activity (38 µg mL-1). The whole plant extracts of Drosera rotundifolia and Drosera intermedia proved to be more effective than the commercial products and the single compounds in its biofilm inhibition activity against Escherichia coli strains. Sundew extracts may serve as a potential therapeutic approach for targeting biofilm production.

A synopsis of the genus Drosera (Droseraceae) in Brazil

A synopsis of the Drosera (Droseraceae) species occurring in Brazil is here presented, providing tools for taxonomic identification and summarizing data as a basis for future studies on diversity and conservation of the genus in the country. Thirty-three taxa, comprising 32 species and a nothotaxon, are recognized for the Brazilian territory. We present an identification key, and, for each taxon, we provide a succint description, a differential diagnosis, notes on distribution, habitat, phenology, conservation status, and a list of representative specimens. Drosera hirtella var. lutescens is lectotypified and raised to species status, lectotypes are further designated for other 18 names, and a neotype is designated for D. intermedia var. tenuis. Drosera species are recorded from all Brazilian states, Minas Gerais being the richest with a total of 21 species. The campos rupestres of eastern Brazil are recognized as the main center of Drosera species diversity in the Neotropics, with 23 species, 13 of which are endemic. Twelve out of the 32 recognized species are considered threatened with extinction (37.5%), reinforcing the Brazilian responsibility for the conservation of global Droseraceae diversity.

A novel approach for reliable qualitative and quantitative prey spectra identification of carnivorous plants combining DNA metabarcoding and macro photography

Prey spectra (the number and composition of captured arthropods) represent a crucial aspect of carnivorous plant ecology, yet remain poorly studied. Traditional morphology-based approaches for prey identification are time-intensive, require specialists with considerable knowledge of arthropod taxonomy, and are hampered by high numbers of unidentifiable (i.e., heavily digested) prey items. We examined prey spectra of three species of closely-related annual Drosera (Droseraceae, sundews) from tropical northern Australia using a novel DNA metabarcoding approach with in-situ macro photography as a plausibility control and to facilitate prey quantity estimations. This new method facilitated accurate analyses of carnivorous plant prey spectra (even of heavily digested prey lacking characteristic morphological features) at a taxonomic resolution and level of completeness far exceeding morphology-based methods and approaching the 100% mark at arthropod order level. Although the three studied species exhibited significant differences in detected prey spectra, little prey specialisation was observed and habitat or plant population density variations were likely the main drivers of prey spectra dissimilarity.

Light emitting diodes optimisation for secondary metabolites production by Droseraceae plants

The most abundant active compound in Droseraceae is plumbagin, a naphthoquinone widely used for medical purposes due to its antimicrobial, antitussive, antimalarial and anticancer properties. In this work, we created a light-emitting diode (LED) based culture illumination setup as an alternative to fluorescent lamps traditionally used as a light source in plant in vitro cultures. The plants of Drosera binata and Drosera peltata cultured under LED illumination grew equally well and produced similar amounts of biologically active compounds as plants grown under fluorescent lamps. The plants were cultured on two media differing in mineral composition, sucrose content and pH. Secondary metabolites were extracted with ethanol from the plants after harvesting. The extracts were subjected to HPLC and microbiological analyses. We observed differences in morphology and secondary metabolism between plants of the same species grown on different media. However, we did not note significant changes in secondary metabolite yield under assessed lighting conditions. We propose LEDs as a more efficient, eco-friendly and economically reasonable source of light for big scale in vitro production of plumbagin in Drosera species than fluorescent lamps.

Breeding systems of the Japanese‐endemic carnivorous sundew species Drosera makinoi and Drosera toyoakensis (Droseraceae)

AbstractIn response to unfavorable environmental conditions, some Drosera species in the northern hemisphere do not open their flowers but form bud‐like flowers. The bud‐like flowers exhibit pseudo‐cleistogamous behavior and produce similar numbers of seeds as open flowers. However, it is not clear how common this type of reproduction is in the genus Drosera. In this study, we examined the effects of flowering (opening flowers/forming bud‐like flowers) and pollinator visitation on seed production in Drosera makinoi and D. toyoakensis, two endemic species in Japan. D. makinoi and D. toyoakensis plants did not open 20%–40% chasmogamous flowers to form bud‐like flowers. The numbers of mature seeds produced by bud‐like flowers were significantly lower than those produced by open flowers (0%–2% of open flowers). In D. makinoi, the percentage of bud‐like flowers correlated negatively with the seed production per plant, suggesting that the production of bud‐like flowers decreased the lifetime reproductive success. In both D. makinoi and D. toyoakensis, pollinator‐excluded flowers produced similar numbers of seeds as control flowers. Our results suggest that pseudo‐cleistogamy does not occur in D. makinoi and D. toyoakensis, and they produce seeds without pollinator visits once flowers open.

Contrasting Dihydronaphthoquinone Patterns in Closely Related Drosera (Sundew) Species Enable Taxonomic Distinction and Identification.

Dihydronaphthoquinones are described as constituents of sundews (Drosera), Venus flytraps (Dionaea), and dewy pines (Drosophyllum) for the first time. As in the corresponding naphthoquinones, these reduced derivatives may occur in two regio-isomeric series distinguished by the relative position of a methyl group (at position 2 or 7 in the naphthalene skeleton), depending on the taxon. Species producing plumbagin (2-methyljuglone, 1) do commonly contain the corresponding dihydroplumbagin (5), while species containing ramentaceone (7-methyljuglone, 2) also contain dihydroramentaceone (7-methyl-β-dihydrojuglone, 6). So far, only few species containing plumbagin (1) and dihydroplumbagin (5) additionally form dihydroramentaceone (6) but not ramentaceone (2). Thus, subtle but constant differences in the chemism of closely related and morphologically similar species reliably define and distinguish taxa within D. sect. Arachnopus, which is taken to exemplify their chemotaxonomic utility. The joint presence of quinones and hydroquinones allows observations and predictions on the chemical structures and the reactions of these intriguing natural products.

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.

Formation and establishment of neopolyploids from sterile hybrids in Drosera in a disturbed environment

Neopolyploid species have been used as model plants to elucidate the consequences of hybridization and polyploidy. Two Drosera species, D. anglica Hudson (2n = 4x = 40) and D. rotundifolia L. (2n = 2x = 20), and the hybrid D. ×obovata Mert. et Koch (2n = 3x = 30), which results from their crossing, have been reported from Hokkaido Island, northern Japan. Recently, we discovered unexpected higher ploidy levels within the population of these Drosera from a post-mined peatland, in Sarobetsu mire of Hokkaido. The ploidy levels were determined by flow cytometry. Polyploids were tagged and monitored at the site for three years. The morphological characteristics of the neopolyploid leaves and flowers were determined and compared to D. anglica, D. rotundifolia and D. ×obovata. Seeds collected from hexaploids were incubated in a laboratory to verify their viability. Hexaploids occurred in the field over the three years of monitoring and produced a few flowers and viable seeds; however, octoploids were extinct in the second year. The leaf shape quantified by the blade length to blade width ratio showed that the ratios of hexaploids were intermediate between D. ×obovata and D. rotundifolia, suggesting that the origin of hexaploids was likely to originate from the triploid D. ×obovata. Polyploidy may occur in disturbed habitats more commonly than previously thought.

Breeding systems of floral colour forms in the Drosera cistiflora species complex.

Variation in plant breeding systems has implications for pollinator-mediated selection on floral traits and the ecology of populations. Here we evaluate pollinator contribution to seed production, self-compatibility and pollen limitation in different floral colour forms of Drosera cistiflora sensu lato (Droseraceae). These insectivorous perennial plants are endemic to fynbos and renosterveld vegetation in the Cape Floristic Region of South Africa, and the species complex includes five floral colour forms (pink, purple, red, white and yellow), some of which are known to be pollinated by beetles. Controlled hand-pollination experiments were conducted in 15 populations of D. cistiflora s.l. (two to four populations per floral colour form) to test whether the colour forms vary in their degree of self-compatibility and their ability to produce seeds through autonomous self-fertilization. Yellow-flowered forms were highly self-incompatible, while other floral colour forms exhibited partial self-compatibility. Seed set resulting from autonomous selfing was very low, and pollinator dependence indices were high in all populations. Since hand cross-pollination resulted in greater seed set than open pollination in 13 of the 15 populations, we inferred that seed production is generally pollen-limited. Drosera cistiflora s.l. typically exhibits high levels of pollinator dependence and pollen limitation. This is unusual among Drosera species worldwide and suggests that pollinators are likely to mediate strong selection on attractive traits such as floral colour and size in D. cistiflora s.l. These results also suggest that the floral colour forms of D. cistiflora s.l. which are rare and threatened are likely to be vulnerable to local extinction if mutualisms were to collapse indefinitely.

A new and endemic species of Drosera (Droseraceae) from Madagascar

Background and aims – This study is part of an ongoing revision of the world Drosera species. During herbarium revisions of Drosera from Madagascar, a new species was identified and is here described.Methods – The species’ morphology is described based on herbarium studies and observation of living plants in situ, and ecological notes from field observations are provided. The species is compared and contextualized within the current subgeneric classification of Drosera.Key results – The new species, Drosera arachnoides, is recognized as most closely related to another Malagasy-endemic, D. humbertii, from which it is morphologically and ecologically distinct. The new species is placed within D. subg. Drosera sect. Ptycnostigma. Based on the restricted occurrence, the species is assessed as Vulnerable, following IUCN categories and criteria. A key to the Drosera species from Madagascar is provided.Conclusion – Drosera arachnoides is the second endemic Drosera species in Madagascar and raises the total number of species on the island to six.

Drosera stipularis, a new species for the D. petiolaris complex from Cape York Peninsula, Queensland

Across tropical northern Australia 14 Drosera species are recognised within the D. petiolaris complex. The complex is placed in section Lasiocephala; a group of perennial sundews mostly characterised by an indumentum of white hairs upon the petiole. Here we describe a new species for the complex, D. stipularis
 Baleeiro, R.W.Jobson & R.L.Barrett, which is known only from white-sand habitats on Cape York Peninsula, Queensland. The new species is allied to D. petiolaris R.Br. ex DC. and D. lanata K.Kondo.

First report of alien Drosera rotundifolia in a high conservation value Patagonian peat bog

SummaryDrosera L. (Droseraceae) is a genus of insectivorous plants distributed worldwide with 240 species, 40 of which are found in South America. In the temperate forests of Chile and Argentina the only species present is D. uniflora. In a peat bog in Nahuel Huapi National Park, Argentina, a new species of Drosera was found in February 2018. To identify the species, we used morphological characters, and in addition, we sequenced two individuals for the nuclear region ITS and the chloroplast gene rbcL. Other Drosera sequences for these molecular regions were downloaded from GenBank, and a phylogenetic analysis was done to confirm the morphological identification of the Patagonian individuals. Morphologically and genetically, the species found in Nahuel Huapi is D. rotundifolia, a mostly Northern Hemisphere species. This is an alien species to the region and is thought to have been transported to the bog by tourists that visit the area. The presence of an exotic species represents a threat to this particular ecosystem with high conservation value. Currently, the National Park is taking control actions order to remove all individuals of the recently detected species. This study represents the first report of an alien species of Drosera in southern South America growing in the wild. This potentially invasive species may not only have negative impacts on the natural peat bog habitats in southern Argentina and Chile, but may also reach bogs in other temperate parts of the world.

Seasonal vegetation shift and wetland dynamics in vulnerable granitic rocky outcrops of Palghat Gap of southern Western Ghats, Kerala, India

Low altitude granitic hillock systems prevalent in Palghat (Palakkad) Gap region of southern Western Ghats were analyzed for seasonal dynamics in wetland taxa associated with marshy ephemeral flush vegetation, small ephemeral pools and deep rock pools. Due to characteristic habitat features, such systems harbor a unique pattern of microhabitats and associated floristic components. Wet phase in rocky outcrops in the monsoon season establishes a hydro-geomorphic habitat that supports establishment of wetland taxa like Eriocaulon, Drosera, Utricularia, Dopatrium, and Rotala. Seasonal shift in the floral associations was evident in tune with wetland dynamics. Wet rocks support ephemeral flush vegetation which display some unique plant associations of species of Eriocaulon, Utricularia, Drosera, Cyanotis, Murdannia, and Lindernia. Small ephemeral pools displayed taxa like Rotala malampuzhensis R.V. Nair, Dopatrium junceum (Roxb.) Buch.-Ham. ex Benth., D. nudicaule (Willd.) Benth., Monochoria vaginalis (Burm.f.) C. Presl, and Cyperus iria L. Rocky pools are the habitats of aquatic angiosperms like Nymphaea nouchali Burm. f., Ludwigia adscendens (L.) H. Hara, Utricularia aurea Lour. and Hydrilla verticillata (L.f.) Royle. The study documented 121 plant taxa from 37 families during a wet phase from rocky outcrops of the study area. Gradual shift in vegetation is evident as water recedes from granitic hillocks. During the period from December to March, the rocky pools dry up which results in a shift in the vegetation pattern where Poaceae members form the dominant elements. As most of the rocky outcrops are exposed to extreme temperature and acute water shortage, the taxa inhabiting such ecosystems tend to evolve much faster than in other habitats. Moreover, the vicinity of these hillocks in the Palghat Gap region to human settlements, face threats like fire, grazing, quarrying, dumping of wastes etc. which may cause considerable loss to the very sensitive plant communities which are not yet fully documented.

The extraordinary botanical diversity of inselbergs in Madagascar

Rabarimanarivo, M.N., B. Ramandimbisoa, N.H. Rakotoarivelo, P.B. Phillipson, S. Andriambololonera, M.W. Callmander & S. Porembski (2019). The extraordinary botanical diversity of inselbergs in Madagascar. Candollea 74: 65–83. In English, English and French abstracts. DOI: http://dx.doi.org/10.15553/c2019v741a8Inselbergs are isolated mountains, mainly granitic or gneissic rock outcrops rising abruptly above surrounding plains. Malagasy inselbergs are often dome-shaped and occur in varying degrees of isolation, but they sometimes form inselberg landscapes, which comprise dozens of individual outcrops. Despite being typical landscape features on Madagascar's high plateau, little data are available on their detailed plant cover. Recent extensive fieldwork, which was conducted between 2010 and 2014, mainly on the central plateau, has resulted in a better knowledge about the floristic composition and habitats of Malagasy inselbergs. The most speciose vascular plant genera were Cynorkis Thouars (18), Cyperus L. (15) and Euphorbia L. (14). Malagasy inselbergs are centres of diversity for succulents (notably species of the genera Aloe L., Euphorbia and Kalanchoe Adans.), carnivorous plants (species of Drosera L. and Utricularia L.) and resurrection plants (notably species of Xerophyta Juss.). The most speciose habitat types were ephemeral flush vegetation and monocotyledonous mats. The latter habitat supports a large number of succulents and resurrection plants. In total 724 taxa out of 338 genera and 107 families have been recorded. Moreover, the variability in floristic composition between different regions is remarkable. Detrimental human impacts include quarrying, grazing, fire and the collection of plants for ornamental purposes (species of Pachypodium Lindl. and Orchidaceae) and as medicine (species of Aloe, Drosera madagascariensis DC., Myrothamnus moschatus (Baill.) Baill.). For the first time, recommendations are made for the conservation of Malagasy inselbergs.