Creating Pyrethrin Mimetic Phosphonates as Chemical Genetics Tools Targeting the GDSL Esterase/Lipase TcGLIP to Investigate Pyrethrin Biosynthesis.

Pyrethrins from Tanacetum cinerariifolium are natural pesticides that exhibit high knockdown and killing activities against flying insects such as disease-spreading mosquitoes. Despite the increasing demand for pyrethrins, the mechanism of pyrethrin biosynthesis remains elusive. To elucidate it, we for the first time created pyrethrin mimetic phosphonates targeting the GDSL esterase/lipase (GELP or TcGLIP) underpinning pyrethrin biosynthesis. The compounds were synthesized by reacting mono-alkyl or mono-benzyl-substituted phosphonic dichloride with pyrethrolone, the alcohol moiety of pyrethrin I and II, and then p-nitrophenol. n-Pentyl (C5) and n-octyl (C8)-substituted compounds were the most potent of the (S)p,(S)c, and (R)p,(S)c diastereomers, respectively. The (S)-pyrethrolonyl group is more effective than the (R)-pyrethrolonyl group in blocking TcGLIP, consistent with the features predicted by TcGLIP models complexed with the (S)p,(S)c-C5 and (R)p,(S)c-C8 probes. The (S)p,(S)c-C5 compound suppressed pyrethrin production in T. cinerariifolium, demonstrating potential as a chemical tool for unravelling pyrethrin biosynthesis.

Effect of ethanol extract from Chrysanthemum cinerariifolium leaves on Ki-67 proliferation and dysplasia severity in a rat model of oral squamous cell carcinoma.

Background: Oral squamous cell carcinoma (OSCC) is a malignant tumor that can rapidly infiltrate the oral epithelial tissue and cause high mortality worldwide because the available therapies are less effective. Chrysanthemum cinerariifolium leaf contains secondary metabolites as anti-inflammatory, antioxidant, anticancer, and antimutagenic. Aims: The study aimed to analyze the ethanolic extract of C. cinerariifolium leaf in reducing proliferation (Ki-67) and the degree of dysplasia in OSCC rats. Methods: This study used male Sprague Dawley induced by 7,12-dimethylbenz(a)anthracene (DMBA) 0.5% and divided into five treatment groups, namely positive control/C+ (sick), negative control/C- (healthy), and treatment group induced with DMBA and given extract C. cinerariifolium leaf with successive doses of T1, T2, and T3 (50, 100, and 200 mg/kg bw). The oral epithelium was stained with hematoxylin and eosin and immunohistochemically stained with a Ki-67 monoclonal antibody. The statistical analysis utilizes the one-way analysis of variance test. Results: The results showed that T1 at a dose of 200 mg/kg bw could significantly reduce Ki-67 expression and the degree of oral epithelial dysplasia (OED; p < 0.05) close to healthy controls. Conclusion: The conclusion shows that C. cinerariifolium leaf extract can be a therapy against OSCC by decreasing cell proliferation and the degree of OED.

TcGLIP GDSL Lipase Substrate Specificity Co-determines the Pyrethrin Composition in Tanacetum cinerariifolium.

Natural pesticides pyrethrins biosynthesized by Tanacetum cinrerariifolium are biodegradable and safer insecticides for pest insect control. TcGLIP, a GDSL lipase underpinning the ester bond formation in pyrethrins, exhibits high stereo-specificity for acyl-CoA and alcohol substrates. However, it is unknown how the enzyme recognizes the other structural features of the substrates and whether such specificity affects the product amount and composition in T. cinrerariifolium. We report here that the cysteamine moiety in (1R,3R)-chrysanthemoyl CoA and the conjugated diene moiety in (S)-pyrethrolone play key roles in the interactions with TcGLIP. CoA released from chrysanthemoyl CoA in the pyrethrin-forming reaction reduces the substrate affinity for TcGLIP by feedback inhibition. (S)-Pyrethrolone shows the highest catalytic efficiency for TcGLIP, followed by (S)-cinerolone and (S)-jasmololone, contributing, at least in part, to determine the pyrethrin compositions in T. cinerariifolium.

The use of Dalmatian pyrethrum daisy and an excipient in the treatment of seborrheic dermatitis.

The active ingredients of the Pyretrin-D trichological cosmetic series, namely benzyl benzoate, Dalmatian pyrethrum daisy, Cistus incanus, tea tree oil and geranium oil, almond acid and arginine were tested in respect to the treatment of seborrheic dermatitis. The paper describes the application of Dalmatian pyrethrum daisy and the excipient. Methods and devices used to confirm the effectiveness of the tested formulations included the TrichoScope Polarizer Dino-Lite (MEDL4HM) and the scanning electron microscope (SEM).

Improvement of fertility parameters with Tribulus Terrestris and Anacyclus Pyrethrum treatment in male rats.

OBJECTIVE: Anacyclus Pyrethrum (AP) and Tribulus Terrestris (TT) have been reported as male infertility treatment in several studies; however, in Iranian traditional medicine these two plants are prescribed simultaneously. In this study, we aimed to determine the effects of AP and TT extracts both separately and simultaneously on the male Wistar rat fertility parameters. MATERIALS AND METHODS: 32 male Wistar rats were divided into 4 groups: Control, TT, AP, and AT treated groups. Treatment continued for 25 days and rats were weighed daily. Their testes were dissected for histological studies. Sperm analysis including sperm count, viability and motility were performed. Serum was obtained to evaluate testosterone, LH and FSH levels. Histological studies were conducted to study Leydig, and Sertoli cells, spermatogonia and spermatid cell numbers, and to measure seminiferous diameter and epithelium thickness. RESULTS: Sperm count increased in all the treatment groups. Sperm viability and motility in AT and AP groups were elevated. TT and AT groups showed signifi cantly increased testosterone level compared to control group (P=004, P=0.000, respectively) and TT, AP and AT treatment groups showed increased LH level (P=0.002, P=0.03 and P=0.000, respectively) compared to control, while only AT group showed increased FSH (p=0.006) compared to control. Histological studies showed signifi cant increase of spermatogonia, Leydig and Sertoli cell numbers and epithelial thickness in AT group compared to other groups. All the treatment groups had higher number of Leydig, spermatogonia and spermatid cells. CONCLUSION: TT and AP improved sexual parameters; however, their simultaneous administration had higher improving effects on studied parameters.

Improvement of fertility parameters with tribulus terrestris and anacyclus pyrethrum treatment in male rats

ABSTRACT Objective Anacyclus Pyrethrum (AP) and Tribulus Terrestris (TT) have been reported as male infertility treatment in several studies; however, in Iranian traditional medicine these two plants are prescribed simultaneously. In this study, we aimed to determine the effects of AP and TT extracts both separately and simultaneously on the male Wistar rat fertility parameters. Materials and Methods 32 male Wistar rats were divided into 4 groups: Control, TT, AP, and AT treated groups. Treatment continued for 25 days and rats were weighed daily. Their testes were dissected for histological studies. Sperm analysis including sperm count, viability and motility were performed. Serum was obtained to evaluate testosterone, LH and FSH levels. Histological studies were conducted to study Leydig, and Sertoli cells, spermatogonia and spermatid cell numbers, and to measure seminiferous diameter and epithelium thickness. Results Sperm count increased in all the treatment groups. Sperm viability and motility in AT and AP groups were elevated. TT and AT groups showed significantly increased testosterone level compared to control group (P=004, P=0.000, respectively) and TT, AP and AT treatment groups showed increased LH level (P=0.002, P=0.03 and P=0.000, respectively) compared to control, while only AT group showed increased FSH (p=0.006) compared to control. Histological studies showed significant increase of spermatogonia, Leydig and Sertoli cell numbers and epithelial thickness in AT group compared to other groups. All the treatment groups had higher number of Leydig, spermatogonia and spermatid cells. Conclusion TT and AP improved sexual parameters; however, their simultaneous administration had higher improving effects on studied parameters.

Pyrethric acid of natural pyrethrin insecticide: complete pathway elucidation and reconstitution in Nicotiana benthamiana.

In the natural pesticides known as pyrethrins, which are esters produced in flowers of Tanacetum cinerariifolium (Asteraceae), the monoterpenoid acyl moiety is pyrethric acid or chrysanthemic acid. We show here that pyrethric acid is produced from chrysanthemol in six steps catalyzed by four enzymes, the first five steps occurring in the trichomes covering the ovaries and the last one occurring inside the ovary tissues. Three steps involve the successive oxidation of carbon 10 (C10) to a carboxylic group by TcCHH, a cytochrome P450 oxidoreductase. Two other steps involve the successive oxidation of the hydroxylated carbon 1 to give a carboxylic group by TcADH2 and TcALDH1, the same enzymes that catalyze these reactions in the formation of chrysanthemic acid. The ultimate result of the actions of these three enzymes is the formation of 10-carboxychrysanthemic acid in the trichomes. Finally, the carboxyl group at C10 is methylated by TcCCMT, a member of the SABATH methyltransferase family, to give pyrethric acid. This reaction occurs mostly in the ovaries. Expression in N. benthamiana plants of all four genes encoding aforementioned enzymes, together with TcCDS, a gene that encodes an enzyme that catalyzes the formation of chrysanthemol, led to the production of pyrethric acid.

Synthesis of citrophilus mealybug sex pheromone using chrysanthemol extracted from Pyrethrum ( Tanacetum cinerariifolium).

A commercial pyrethrum extract was used as a source of chrysanthemol for the synthesis of the citrophilus mealybug ( Pseudococcus calceolariae) sex pheromone. The chrysanthemic acid esters (pyrethrins I) were isolated and subsequently reduced to obtain chrysanthemol, which was used for ester pheromone synthesis. Field tests showed that the pheromone synthesized using plant-derived chrysanthemol was as attractive to male P. calceolariae as the pheromone obtained using a commercial isomeric chrysanthemol mixture.

Pyrethrum-extract induced autophagy in insect cells: A new target?

Pyrethrum extract (PY) is a natural insecticide that is extensively used across the world, and its insecticidal activity is attributed to the presence of six active esters known as pyrethrins. PY targets the nervous systems of insects by delaying the closure of voltage-gated sodium ion channels in the nerve cells. However, limited information is available regarding the toxicity and detailed mechanisms of PY activity. This study is aimed at understanding the toxicity effect and the underlying mechanisms of PY in cellular level, which have not yet been investigated on the non-nervous system of insects. Results of the MTT assay showed that the viability of Sf9 cells was inhibited by PY in a time- and concentration-dependent manner, and observation under a microscope revealed accumulation of intracellular vacuoles. Monodansylcadaverine staining analysis and transmission electron microscope images revealed typical autophagic morphological changes in PY-treated Sf9 cells. Autophagy-related proteins such as LC3, p62, and beclin-1 were detected using by Western blotting. Protein expression levels of LC3-II and beclin-1 were upregulated while that of p62 was markedly downregulated in a dose-dependent manner upon the PY treatment in Sf9 cells. In conclusion, these results indicate that PY could induce autophagy in the non-nervous system of insects which may contribute to its insecticidal mechanism.

Anacyclus Pyrethrum Extract Exerts Anticancer Activities on the Human Colorectal Cancer Cell Line (HCT) by Targeting Apoptosis, Metastasis and Cell Cycle Arrest.

INTRODUCTION: Colorectal cancer is the second leading cause of cancer mortality in the USA. There are a number of medicinal plants triggering apoptosis response in cancer cells, thus have a therapeutic potential. On the other hand, due to traditional uses and availability of Anacyclus pyrethrum extract, we decided to evaluate the efficacy of this medicinal herb on human colorectal cancer cell line (HCT). MATERIALS AND METHODS: In the present study, the cytotoxic effects of Anacyclus pyrethrum extract were assessed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, and trypan blue viability dye. Then, flow cytometry assay was exploited to measure cell death and apoptosis stage. The scratch test was exploited to assess the effect of Anacyclus pyrethrum on the migration of cancer cells. The expression levels of Caspase 3, Bcl-2, MMP1, and Vimentin genes were quantified by real-time PCR. Finally, cell cycle was analyzed by flow cytometry. RESULTS: MTT assay showed that Anacyclus pyrethrum extract significantly inhibited the cell growth. According to the flow cytometry assay result, the herbal extract was able to induce apoptosis in colorectal cancer cells. Our findings also demonstrated that the plant extract substantially increases the caspase 3 mRNA expression, while decreases Bcl-2, MMP1, and Vimentin. Cell cycle arrest occurred in G1 stage, due to the results of flow cytometry. CONCLUSION: These results indicate that Anacyclus pyrethrum extract can successfully induce apoptosis in HCT cells. Therefore, it could be used as a novel therapeutic candidate for colorectal cancer treatment.

Molecular Markers for Pyrethrin Autoxidation in Stored Pyrethrum Crop: Analysis and Structure Determination.

Pyrethrum is a natural insecticide extracted from Tanacetum cinerariifolium. Six esters, the pyrethrins, are responsible for the extract's insecticidal activity. The oxidative degradation of pyrethrins through contact with aerial oxygen is a potential cause of pyrethrin losses during pyrethrum manufacture. Described here is the first investigation of the autoxidation chemistry of the six pyrethrin esters isolated from pyrethrum. It was found that pyrethrins I and II, the major pyrethrin esters present in pyrethrum, undergo autoxidation more readily than the minor pyrethrin esters, the jasmolins and cinerins. Chromatographic analysis of pyrethrin I and II autoxidation mixtures showed some correlation with a similar analysis performed on extracts from T. cinerariifolium crop, which had been stored for 12 weeks without added antioxidants. Two pyrethrin II autoxidation products were isolated, characterized, and shown to be present in extracts of stored T. cinerariifolium crop, confirming that autoxidation of pyrethrin esters does occur during crop storage.

Biosynthesis of sesquiterpene lactones in pyrethrum (Tanacetum cinerariifolium).

The daisy-like flowers of pyrethrum (Tanacetum cinerariifolium) are used to extract pyrethrins, a botanical insecticide with a long history of safe and effective use. Pyrethrum flowers also contain other potential defense compounds, particularly sesquiterpene lactones (STLs), which represent problematic allergenic residues in the extracts that are removed by the pyrethrum industry. The STLs are stored in glandular trichomes present on the pyrethrum achenes, and have been shown to be active against herbivores, micro-organisms and in the below-ground competition with other plants. Despite these reported bioactivities and industrial significance, the biosynthetic origin of pyrethrum sesquiterpene lactones remains unknown. In the present study, we show that germacratrien-12-oic acid is most likely the central precursor for all sesquiterpene lactones present in pyrethrum. The formation of the lactone ring depends on the regio- (C6 or C8) and stereo-selective (α or ß) hydroxylation of germacratrien-12-oic acid. Candidate genes implicated in three committed steps leading from farnesyl diphosphate to STL and other oxygenated derivatives of germacratrien-12-oic acid were retrieved from a pyrethrum trichome EST library, cloned, and characterized in yeast and in planta. The diversity and distribution of sesquiterpene lactones in different tissues and the correlation with the expression of these genes are shown and discussed.

Chemical diversity of the natural populations of Dalmatian pyrethrum (Tanacetum cinerariifolium (TREVIR.) SCH.BIP.) in Croatia.

Dalmatian pyrethrum (Tanacetum cinerariifolium (TREVIR.) SCH.BIP.) is a plant species endemic to the east Adriatic coast. The bioactive substance of Dalmatian pyrethrum is a natural insecticide, pyrethrin, a mixture of six active components (pyrethrins I and II, cinerins I and II, and jasmolins I and II). The insecticidal potential of pyrethrin was recognized decades ago, and dried and ground flowers have traditionally been used in Croatian agriculture and households. A total of 25 Dalmatian pyrethrum populations from Croatia were studied to determine the pyrethrin content and composition, and to identify distinct chemotypes. The total pyrethrin content ranged from 0.36 to 1.30% (dry flower weight; DW) and the pyrethrin I/pyrethrin II ratio ranged from 0.64 to 3.33%. The statistical analyses revealed that the correlations between the percentage of pyrethrin I and of all the other components were significant and negative. The total pyrethrin content was positively correlated with the percentage of pyrethrin I and negatively correlated with cinerin II. The multivariate analysis of the chemical variability enabled the identification of five chemotypes among 25 Dalmatian pyrethrum populations. The chemical characterization of indigenous Dalmatian pyrethrum populations may serve as a good background for future breeding and agricultural exploitation.

Consumer and farmer safety evaluation of application of botanical pesticides in black pepper crop protection.

This study presents a consumer and farmer safety evaluation on the use of four botanical pesticides in pepper berry crop protection. The pesticides evaluated include preparations from clove, tuba root, sweet flag and pyrethrum. Their safety evaluation was based on their active ingredients being eugenol, rotenone, ß-asarone and pyrethrins, respectively. Botanical pesticides from Acorus calamus are of possible concern because of the genotoxic and carcinogenic ingredient ß-asarone although estimated margins of exposure (MOE) for consumers indicate a low priority for risk management. For the other three botanical pesticides the margin of safety (MOS) between established acute reference doses and/or acceptable daily intake values and intake estimates for the consumer, resulting from their use as a botanical pesticide are not of safety concern, with the exception for levels of rotenone upon use of tuba root extracts on stored berries. Used levels of clove and pyrethrum as botanical pesticides in pepper berry crop production is not of safety concern for consumers or farmers, whereas for use of tuba root and sweet flag some risk factors were defined requiring further evaluation and/or risk management. It seems prudent to look for alternatives for use of sweet flag extracts containing ß-asarone.

A systematic review of mosquito coils and passive emanators: defining recommendations for spatial repellency testing methodologies.

Mosquito coils, vaporizer mats and emanators confer protection against mosquito bites through the spatial action of emanated vapor or airborne pyrethroid particles. These products dominate the pest control market; therefore, it is vital to characterize mosquito responses elicited by the chemical actives and their potential for disease prevention. The aim of this review was to determine effects of mosquito coils and emanators on mosquito responses that reduce human-vector contact and to propose scientific consensus on terminologies and methodologies used for evaluation of product formats that could contain spatial chemical actives, including indoor residual spraying (IRS), long lasting insecticide treated nets (LLINs) and insecticide treated materials (ITMs). PubMed, (National Centre for Biotechnology Information (NCBI), U.S. National Library of Medicine, NIH), MEDLINE, LILAC, Cochrane library, IBECS and Armed Forces Pest Management Board Literature Retrieval System search engines were used to identify studies of pyrethroid based coils and emanators with key-words "Mosquito coils" "Mosquito emanators" and "Spatial repellents". It was concluded that there is need to improve statistical reporting of studies, and reach consensus in the methodologies and terminologies used through standardized testing guidelines. Despite differing evaluation methodologies, data showed that coils and emanators induce mortality, deterrence, repellency as well as reduce the ability of mosquitoes to feed on humans. Available data on efficacy outdoors, dose-response relationships and effective distance of coils and emanators is inadequate for developing a target product profile (TPP), which will be required for such chemicals before optimized implementation can occur for maximum benefits in disease control.

Bidirectional secretions from glandular trichomes of pyrethrum enable immunization of seedlings.

Glandular trichomes are currently known only to store mono- and sesquiterpene compounds in the subcuticular cavity just above the apical cells of trichomes or emit them into the headspace. We demonstrate that basipetal secretions can also occur, by addressing the organization of the biosynthesis and storage of pyrethrins in pyrethrum (Tanacetum cinerariifolium) flowers. Pyrethrum produces a diverse array of pyrethrins and sesquiterpene lactones for plant defense. The highest concentrations accumulate in the flower achenes, which are densely covered by glandular trichomes. The trichomes of mature achenes contain sesquiterpene lactones and other secondary metabolites, but no pyrethrins. However, during achene maturation, the key pyrethrin biosynthetic pathway enzyme chrysanthemyl diphosphate synthase is expressed only in glandular trichomes. We show evidence that chrysanthemic acid is translocated from trichomes to pericarp, where it is esterified into pyrethrins that accumulate in intercellular spaces. During seed maturation, pyrethrins are then absorbed by the embryo, and during seed germination, the embryo-stored pyrethrins are recruited by seedling tissues, which, for lack of trichomes, cannot produce pyrethrins themselves. The findings demonstrate that plant glandular trichomes can selectively secrete in a basipetal direction monoterpenoids, which can reach distant tissues, participate in chemical conversions, and immunize seedlings against insects and fungi.

Use of natural pyrethrum to control the red swamp crayfish Procambarus clarkii in a rural district of Italy.

BACKGROUND: The crayfish Procambarus clarkii inflicts severe ecological and economic damages in Europe. To develop an efficient method for its control, four experiments were carried out to assess the impact of natural pyrethrum (i.e. Pyblast) on crayfish: (1) the 24 h LC(100) and LC(50) were quantified on crayfish; (2) the breakdown time of the 24 h LC(100) was assessed using Daphnia magna as a bioindicator; the effects of 24 h LC(100) on crayfish were investigated by applying the biocide into burrows (3) and in a drainage channel (4). RESULTS: Pyblast concentrations of 0.05 and 0.02 mg L(-1) corresponded to 24 h LC(100) and LC(50) respectively. The concentration of 0.05 mg L(-1) broke down after 72 h, whereas 0.02 mg L(-1) did not cause any significant mortality in D. magna after 24 h. However, 0.05 mg L(-1) had no effect on crayfish when introduced into the burrows, but led to a mortality of 95% when applied in the water. CONCLUSION: Experimental evidence is provided for the efficacy of Pyblast to control invasive crayfish. Obviously, before its use on a large scale, further studies are needed to find a concentration that will achieve the target 100% mortality with the shortest recovery time of the environment.

Identification and characterization of a GDSL lipase-like protein that catalyzes the ester-forming reaction for pyrethrin biosynthesis in Tanacetum cinerariifolium- a new target for plant protection.

Although natural insecticides pyrethrins produced by Tanacetum cinerariifolium are used worldwide to control insect pest species, little information is known of their biosynthesis. From the buds of T. cinerariifolium, we have purified a protein that is able to transfer the chrysanthemoyl group from the coenzyme A (CoA) thioester to pyrethrolone to produce pyrethrin I and have isolated cDNAs that encode the enzyme. To our surprise, the active principle was not a member of a known acyltransferase family but a member of the GDSL lipase family. The recombinant enzyme (TcGLIP) was expressed in Escherichia coli and displayed the acyltransferase reaction with high substrate specificity, recognized the absolute configurations of three asymmetric carbons and also showed esterase activity. A S40A mutation in the Block I domain reduced both acyltransferase and esterase activities, which suggested an important role of this serine residue in these two activities. The signal peptide directed the localization of TcGLIP::enhanced green fluorescent protein (EGFP) fusion, as well as EGFP, to the extracellular space. High TcGLIP gene expression was observed in the leaves of mature plants and seedlings as well as in buds and flowers, a finding that was consistent with the pyrethrin I content in these parts. Expression was enhanced in response to wounding, which suggested that the enzyme plays a key role in the defense mechanism of T. cinerariifolium.

Determination of natural pyrethrins by liquid chromatography-electron ionisation-mass spectrometry.

INTRODUCTION: Pyrethrum extract is a mixture of six insecticidal compounds from the flower heads of Chrysanthemum cinerariaefolium L.. Since they only have low to moderate mammalian toxicity they can be used as natural insecticides in agriculture or to develop low cost and safe dermatological formulations. Because of the thermal instability of pyrethrins, analytical methods based on liquid chromatography (LC) are preferred over those based on gas chromatography (GC). A few applications using LC with mass spectrometry detection are presented in the literature. Current protocols for their characterisation by LC rely on the use of less sophisticated detectors such as UV detection. OBJECTIVE: To develop the first liquid chromatography-electron ionisation-mass spectrometry (LC-EI-MS) method for pyrethrins detection and quantitation in pyrethrum extracts. METHODOLOGY: A commercial pyrethrum extract and various samples of flower heads from C. cinerariaefolium L. were investigated using reversed-phase nano-liquid chromatography coupled to direct electron ionisation-mass spectrometry (nanoLC-direct EI-MS). The eluted compounds were identified through searches of the US National Institute of Standards and Technology (NIST) library, exploiting the direct EI capability to produce high quality EI mass spectra. RESULTS: The method demonstrated satisfactory sensitivity (limit of detection (LOD) range: 0.04-0.38 mg/g), linearity (R² range: 0.9740-0.9983) and precision (RSD% range: 4-13%) for the quantitation of the natural pyrethrins in extracts from C. cinerariaefolium L. CONCLUSION: The nanoLC-direct EI-MS technique can be a useful tool for the detection of pyrethrins.