Two Pelargonium species which are indigenous to South Africa; P. sidoides DC and P. reniforme Curt., are highly valued traditional remedies used primarily for the treatment of upper respiratory tract ...infections. The ethnobotanical value of P. sidoides has led to the commercialisation of herbal medicinal products such as Umckaloabo super( registered ) that are marketed internationally. Although the two species can be distinguished by leaf shape and flower colour, the rhizomes which are used for preparation of the commercial extracts are morphologically similar. Non-targeted super(1)H-NMR and UHPLC-MS metabolomic approaches were applied to differentiate P. sidoides and P. reniforme extracts. qNMR was used for the quantitative comparison of the marker constituents occurring in both species. Both super(1)H-NMR and UHPLC-MS in combination with multivariate algorithms revealed a chemical distinction between the two species. Umckalin was identified as the marker compound in P. sidoides (0.0012-0.2760 % (w/w)) by UHPLC-MS, which occurred in trace quantities in P. reniforme (0-0.0016 % (w/w)). Conversely, coumarins such as scopoletin, isofraxoside and a scopoletin isomer were reported to occur in relatively higher levels in P. reniforme compared to P. sidoides.
Summary
Geraniol, citronellol and their esters are high‐value acyclic monoterpenes used in food technology, perfumery and cosmetics. A major source of these compounds is the essential oil of ...rose‐scented geraniums of the genus Pelargonium. We provide evidence that their biosynthesis mainly takes place in the cytosol of glandular trichomes via geranyl monophosphate (GP) through the action of a Nudix hydrolase. Protein preparations could convert geranyl diphosphate (GDP) to geraniol in in vitro assays, a process which could be blocked by inorganic phosphatase inhibitors, suggesting a two‐step conversion of GDP to geraniol. Pelargonium graveolens chemotypes enriched in either geraniol or (−)‐citronellol accumulate GP or citronellyl monophosphate (CP), respectively, the presumed precursors to their monoterpenoid end products. Geranyl monophosphate was highly enriched in isolated glandular trichomes of lines producing high amounts of geraniol. In contrast, (−)‐isomenthone‐rich lines are depleted in these prenyl monophosphates and monoterpene alcohols and instead feature high levels of GDP, the precursor to plastidic p‐menthane biosynthesis. A Nudix hydrolase cDNA from Pelargonium glandular trichomes, dubbed PgNdx1, encoded a cytosolic protein capable of hydrolyzing GDP to GP with a KM of about 750 nm but is only weakly active towards farnesyl diphosphate. In citronellol‐rich lines, GDP, GP and CP were detected in nearly equimolar amounts, while citronellyl diphosphate was absent, suggesting that citronellol biosynthesis may proceed by reduction of GP to CP in this species. These findings highlight the cytosol as a compartment that supports monoterpene biosynthesis and expands the roles of Nudix hydrolases in the biosynthesis of plant volatiles.
Significance Statement
Monoterpenes are ordinarily synthesized from geranyl diphosphate in the plastid, but rose‐scented geraniums make acyclic monoterpenes such as geraniol from geranyl monophosphate in the cytosol of glandular trichomes. We show the involvement of a Nudix hydrolase in this process, a family of enzymes with emerging roles in plant terpenoid metabolism.
Pelargonium sidoides is a medical herb and respective extracts are used very frequently for the treatment of respiratory tract infections. However, the effects of Pelargonium sidoides and a special ...extract prepared from its roots (EPs 7630) on human immune cells are not fully understood. Here we demonstrate that EPs 7630 induced a rapid and dose-dependent production of TNF- alpha , IL-6, and IL-10 by human blood immune cells. This EPs 7630-induced cytokine profile was more pro-inflammatory in comparison with the profile induced by viral or bacterial infection-mimicking agents. The search for EPs 7630 target cells revealed that T-cells did not respond to EPs 7630 stimulation by production of TNF- alpha , IL-6, or IL-10. Furthermore, pretreatment of T-cells with EPs 7630 did not modulate their TNF- alpha , IL-6, and IL-10 secretion during subsequent activation. In contrast to lymphocytes, monocytes showed clear intracellular TNF- alpha staining after EPs 7630 treatment. Accordingly, EPs 7630 predominantly provoked activation of MAP kinases and inhibition of p38 strongly reduced the monocyte TNF- alpha production. The pretreatment of blood immune cells with EPs 7630 lowered their secretion of TNF- alpha and IL-10 and caused an IL-6 dominant response during second stimulation with viral or bacterial infection-mimicking agents. In summary, we demonstrate that EPs 7630 activates human monocytes, induces MAP kinase-dependent pro-inflammatory cytokines in these cells, and specifically modulates their production capacity of mediators known to lead to an increase of acute phase protein production in the liver, neutrophil generation in the bone marrow, and the generation of adaptive Th17 and Th22 cells.
Stevens' Cure (Umckaloabo) emerged as a patent medicine claiming to treat tuberculosis in the United Kingdom at the beginning of the 20th century. However, due to its identity being shrouded in ...secrecy, it was never truly accepted by the medical community. It was "rediscovered" in the 1970s and subsequently developed into a very popular and successful phytopharmaceutical for the treatment of upper respiratory tract infections. Whether Stevens' Cure contained the same ingredient(s) as the modern Umckaloabo has not yet been demonstrated. We attempted to elucidate for the first time the identity of the original ingredient by comparative analysis of historical product samples. Three historical samples of Stevens' Cure were compared with
DC. and
Curt. root per UPLC-MS analysis. We confirm that the ingredient-
DC.-is indeed the same as used in modern phytotherapy. We also attribute the first ethnopharmacological record of
DC. being used for the treatment of tuberculosis to C. H. Stevens, the "creator" of Umckaloabo.
The aim of this study was to assess EDTA-assisted Pb and Cd phytoextraction potential of locally grown Pelargonium hortorum and Pelargonium zonale. Plants were exposed to different levels of Pb ...(0-1500 mg kg
−1
) and Cd (0-150 mg kg
−1
) in the absence or presence of EDTA (0-5 mmol kg
−1
). P. hortorum and P. zonale accumulated 50.9% and 42.2% higher amount of Pb in shoots at 1500 mg kg
−1
Pb upon addition of 5 mmol kg
−1
EDTA. Plant dry biomass decreased 46.8% and 64.3% for P. hortorum and P. zonale, respectively at the combination of 1500 mg kg
−1
Pb and 5 mmol kg
−1
EDTA. In Cd and EDTA-treated groups, P. hortorum and P. zonale accumulated 2.7 and 1.6-folds more Cd in shoots at 4 and 2 mmol kg
−1
EDTA, respectively, in 150 mg Cd kg
−1
treatment. Plant dry biomass of P. hortorum and P. zonale was reduced by 46.3% and 71.3%, respectively, in soil having 150 mg Cd kg
−1
combined with 5 mmol kg
−1
EDTA. Translocation factor and enrichment factor of both plant cultivars at all treatment levels were >1. Overall, the performance of P. hortorum was better than that of P. zonale for EDTA-assisted phytoextraction of Pb and Cd.
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•SEM studies reveal that the Cr accumulation in vascular bundles.•Siderophore producing Pseudomonas in plants to enhance their phytoextraction.•No detectable amount of metal found in ...oil of geranium.•The glandular trichomes were probably the main site of essential oil synthesis.
Bacterial strains PsF84 and PsF610 were isolated from tannery sludge polluted soil, Jajmau, Kanpur, India. 16S rRNA gene sequence and phylogenetic analysis confirmed the taxonomic affiliation of PsF84 as Pseudomonas monteilii and PsF610 as Pseudomonas plecoglossicida. A greenhouse study was carried out with rose-scented geranium (Pelargonium graveolenscv. bourbon) grown in soil treated with tannery sludge in different proportions viz. soil: sludge ratio of 100:0, 25:75, 50:50, 75:25 and 0:100 to evaluate the effects of bacterial inoculation on the heavy metal uptake. The isolates solubilized inorganic phosphorus and were capable of producing indole acetic acid (IAA) and siderophore. The isolate PsF84 increased the dry biomass of shoot by 44%, root by 48%, essential oil yield 43% and chlorophyll by 31% respectively over uninoculated control. The corresponding increase with the isolate PsF610 were 38%, 40%, 39% and 28%, respectively. Scanning electron microscopic (SEM) studies reveal that the Cr(VI) accumulation resulted in breakdown of vascular bundles and sequesters Cr(VI) in roots. The glandular trichomes (GT) were investigated using SEM studies as these glands are probably the main site of essential oil synthesis. Owing to its wide action spectrum, these isolates could serve as an effective metal sequestering and bioinoculants due to the production of IAA, siderophore and solubilization of phosphate for geranium in metal-stressed soil. The present study has provided a new insight into the phytoremediation of metal-contaminated soil.
Participation of nitric oxide (NO) in cross-talk between ivy pelargonium (Pelargonium peltatum) leaves and Botrytis cinerea was investigated using electrochemical and biochemical approaches. In ...response to the necrotroph, leaves initiated a near-immediate NO burst, but the specificity of its generation was dependent on the genetic makeup of the host plant. In the resistant cultivar, a strong NO burst was followed by a wave of secondary NO generation, shown by bio-imaging with DAF-2DA. The epicentre of NO synthesis was located in targeted cells, which exhibited a TUNEL-positive reaction. Soon after the challenge, an elevated concentration of hydrogen peroxide (H₂O₂) was correlated with a reversible inhibition of catalase (CAT), ascorbate peroxidase (APX), and suppression of ethylene synthesis. The induced NO generation initially expanded and then gradually disappeared on successive days, provoking noncell-death-associated resistance with an enhanced pool of antioxidants, which finally favoured the maintenance of homeostasis of surrounding cells. By contrast, in the susceptible pelargonium, a weak NO burst was recorded and further NO generation increased only as the disease progressed, which was accompanied by very intensive H₂O₂ and ethylene synthesis. The pathogen colonizing susceptible cells also acquired the ability to produce considerable amounts of NO and enhanced nitrosative and oxidative stress in host tissues.
The essential oil of Pelargonium graveolens (rose-scented geranium), an important aromatic plant, comprising mainly mono- and sesqui-terpenes, has applications in food and cosmetic industries. This ...study reports the characterization of isoprenyl disphosphate synthases (IDSs) involved in P. graveolens terpene biosynthesis. The six identified PgIDSs belonged to different classes of IDSs, comprising homomeric geranyl diphosphate synthases (GPPSs; PgGPPS1 and PgGPPS2), the large subunit of heteromeric GPPS or geranylgeranyl diphosphate synthases (GGPPSs; PgGGPPS), the small subunit of heteromeric GPPS (PgGPPS.SSUI and PgGPPS.SSUII), and farnesyl diphosphate synthases (FPPS; PgFPPS).All IDSs exhibited maximal expression in glandular trichomes (GTs), the site of aroma formation, and their expression except PgGPPS.SSUII was induced upon treatment with MeJA. Functional characterization of recombinant proteins revealed that PgGPPS1, PgGGPPS and PgFPPS were active enzymes producing GPP, GGPP/GPP, and FPP respectively, whereas both PgGPPS.SSUs and PgGPPS2 were inactive. Co-expression of PgGGPPS (that exhibited bifunctional G(G)PPS activity) with PgGPPS.SSUs in bacterial expression system showed lack of interaction between the two proteins, however, PgGGPPS interacted with a phylogenetically distant Antirrhinum majus GPPS.SSU. Further, transient expression of AmGPPS.SSU in P. graveolens leaf led to a significant increase in monoterpene levels. These findings provide insight into the types of IDSs and their role in providing precursors for different terpenoid components of P. graveolens essential oil.
•Six IDSs that are highly expressed in glandular trichomes of P. graveolens were functionally characterized.•Results revealed geranium has a homomeric GPPS, a bifunctional G(G)PPS, and a FPPS involved in terpenoid precursor formation.•Enzyme kinetics indicated that both homomeric and bifunctional G(G)PPS provide precursors for monoterpene biosynthesis.
Soil amendments like ethylene-diamine-tetraacetic-acid (EDTA) have extensively been used for enhancing lead (Pb) phytoextraction. But due to its toxic effects, environment friendly substitute is ...required. Therefore, the present study was conducted to investigate the effect of EDTA and Di-iso-propanol-amine (DIPA) to enhance Pb phytoavailability and uptake by Pelargonium hortorum along with comparative toxicities of both organic amendments. For this purpose, soil was spiked with Pb concentrations (0, 500, 750, 1000 and 1500 mg kg1) and amended with EDTA and DIPA at dosage levels (0, 1.5, 3, 5, 7.5, 10 mmol kg−1) for plantation of Pelargonium hortorum. Soil samples were extracted with MgCl2, plant samples were acid digested and analyzed for metal content. Biomass and root/shoot length of Pelargonium hortorum was decreased with increase in concentration of Pb and chelating agents. Phytoavailability of Pb at 1500 mg kg−1 with EDTA 10 mmol kg−1 was 0.3-folds in comparison to DIPA at the same dosage. Pelargonium hortorum plants amended with EDTA and DIPA at 10 mmol kg−1 with Pb 1000 mg kg−1 were found to uptake Pb 5.3-fold and 2.5-folds, respectively in comparison to Pb 1000 mg kg−1 alone. Pb uptake decreased at 1500 mg kg−1 with both chelating agents. The EDTA alone and in combination with 1500 mg Pb kg−1 showed maximum genotoxicity by reducing the mitotic index and increasing the micronuclei formation. EDTA+Pb showed maximum toxicity followed by Pb and DIPA. Overall, 10 mmol kg−1 of EDTA and DIPA performed better among all dosages in enhancing phytoavailability and uptake of Pb. DIPA showed less toxicity than that caused by EDTA, with comparable ability to promote Pb phytoextraction.
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•The application of EDTA and DIPA was assessed for Pb bioavailability and uptake.•EDTA was comparatively more effective with reference to DIPA.•Phytotoxicity and genotoxicity by Pb were pronounced with EDTA application.•DIPA promoted Pb phytoextraction effectively along with reduction in toxicities.
Citronellol is a pleasant-smelling compound produced in rose (Rosa spp.) flowers and in the leaves of many aromatic plants, including pelargoniums (Pelargonium spp.). Although geraniol production has ...been well studied in several plants, citronellol biosynthesis has been documented only in crab-lipped spider orchid (Caladenia plicata) and its mechanism remains open to question in other species. We therefore profiled 10 pelargonium accessions using RNA sequencing and gas chromatography-MS analysis. Three enzymes from the progesterone 5β-reductase and/or iridoid synthase-like enzymes (PRISE) family were characterized in vitroand subsequently identified as citral reductases (named PhCIRs). Transgenic RNAi lines supported a role for PhCIRs in the biosynthesis of citronellol as well as in the production of mint-scented terpenes. Despite their high amino acid sequence identity, the 3 enzymes showed contrasting stereoselectivity, either producing mainly (S)-citronellal or a racemate of both (R)- and (S)-citronellal. Using site-directed mutagenesis, we identified a single amino acid substitution as being primarily responsible for the enzyme's enantioselectivity. Phylogenetic analysis of pelargonium PRISEs revealed 3 clades and 7 groups of orthologs. PRISEs from different groups exhibited differential affinities toward substrates (citral and progesterone) and cofactors (NADH/NADPH), but most were able to reduce both substrates, prompting hypotheses regarding the evolutionary history of PhCIRs. Our results demonstrate that pelargoniums evolved citronellol biosynthesis independently through a 3-step pathway involving PRISE homologs and both citral and citronellal as intermediates. In addition, these enzymes control the enantiomeric ratio of citronellol thanks to small alterations of the catalytic site.
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