Pyrethrum extracts

Recently a new constituent of pyrethrum extract was described by Godin et al. (9) jasmolin II, the cir-pent-2-enylrethronyl ester of pyrethric acid. Jasmolin II differs from pyrethrin II in that the terminal double bond of the alcoholic side chain is saturated. This constituent forms about 3% of the total pyrethrins. Jasmolin II is less toxic to the insects tested than a similar concentration of pyrethrins. The pyrethrum extract was 16 to 17 times as toxic as jasmolin II to Aedes aegypti and Fhaedon cochlearia adults, less than 17 times... 

Jasmolin II in pure form was nearly equal to cinerin II in toxicity to houseflies but much less when synergized. The synergistic factor of the synergized compounds is pyrethrum extract 9.6 jasmolin II, 7.0 cinerin II, 12.0. 

Sawicki et al. (33) prepared by reconstitution pure samples of pyrethrins I and II and cinerins I and II and compared the toxicity of these esters with the regular pyrethrum extract on houseflies 5 to 6 days old. 

Partition column chromatography for separating several of the primary constituents of the pyrethrum extract has been reported. The elution pattern for some of the constituents of the pyrethrum mixture recovered from the partition column is shown in Table I. 

Thin-Layer Chromatography. A study using thin-layer chromatography both for separating components of a pyrethrum extract and for purifying single components has been made. Other reports have mentioned the use of thin-layer chromatography in various connections related to pyrethrin analysis. Stahl (14) reported on pyre-thrins I and II and evidence for presence of other compounds from... 

After World War II, the production of pyrethrum in Japan fell markedly and declined to only 1,000 tons in terms of dried flowers in 1965. At present, pyrethrum is not cultivated in Japan and the main producers are Kenya, Tanzania, Tasmania, and China, with worldwide production in 2010 amounting to around 10,000 tons of dried flowers. Dried flowers are extracted and purified at pyrethrum-extracting factories on the spot, producing 25-50% pyrethrin extracts. While pyrethrum extracts have been replaced with various synthetic pyrethroids, they are still used in houses, food factories, gardens, and organic farms, all of which emphasize the importance of safety. Katsuda [1] reported that natural pyrethrins showed a low development of resistance by flies and mosquitoes compared with many synthetic pyrethroids, against which a high development of cross-resistance was observed. 

Sanitary insects coming into houses are largely divided into two types - flying insects and crawling insects. The use of pyrethrum powders as an insecticide for crawling insects was started around 1855 in the USA and in 1886 in Japan. Mosquito coils were developed in 1890 in Japan and oil formulations containing pyrethrum extract were available in 1919 in the USA. 

Pyrethroids are a class of synthetic insecticides designed and optimized based on the structure of the pyrethrins found in natural pyrethrum extracted from chrysanthemum flowers [1, 2], Pyrethroids are widely used to control insect pests in agriculture and public health because of their relative safety for humans and high insecticidal potency [3]. 

Synonyms Pyrethrin I or II Cinerin I or II Jasmolin I or II. Note Pyrethrum flowers yield pyrethrum extract, of which the insecticidal constituents are collectively the pyrethrins or the natural pyrethrins ... 

The pediculicides include permethrin, malathion, lindane and combinations of pyrethrum extract or bioalletrin with piperonylbutoxide. Permethrin, lindane and benzyl benzoate are also effective scabi-cides. 

Bioallethrin is a synthetic pyrethrin insecticide. Piperonylbutoxide, a weak insecticide itself, has synergistic activity. The same holds true for the combination of pyrethrum extract with piperonylbutoxide. These combinations have the same efficacy as permethrin. Local irritation occurs frequently effect and contact with mucous membranes and the eyes must be avoided. 

One of the limitations of HPLC has been its restriction to the analytical mode of operation. However, increasing attention has been focused upon the development of preparative systems. For example, the use of HPLC in the isolation and identification of the components of complex mixtures of pyrethrum extracts, progesterone, and cholesteryl phenylace-tate was described [265]. Various large diameter columns for preparative work have also been developed such as that available from Du Pont and described by Wolf [266] and by De Stefano [267] in a variety of preparative applications. 

Synthetic pyrethroids (cypermethrin, permethrin) and natural pyrethrins (pyrethrum extract) combined with piperonyl butoxide constitute the most important class of insecticide applied topically to horses (Table 5.7). The liquid concentrate containing cypermethrin which, after dilution, is applied to horses by spray contains a mixture of the isomers in equal proportion (cis trans 50 50). 

Head, S.W., Sylvester, N.K. and Challiimr, 5K, (1968). The effect of pipenonyl bn [oxide on the stability of ti Itms of crude and retired pyrethrum extract. Pyretfi. PosiV, 14. 

Pyrethrins These have low mammalian toxicity. Separation of constituents of pyrethrum extracts has been achieved by chromatography on permaphose ODS. 

Since 2500 BC, farmers have used pesticides to prevent damage to their crops. The first known pesticide was elemental sulfur, used to dust crops in Sumeria about 4500 years ago. By the fifteenth century, pesticides containing arsenic, mercury, and lead were being applied to crops. In the seventeenth century, nicotine was extracted from tobacco leaves as nicotine sulfate for use as an insecticide. In the nineteenth century, two more natural pesticides were introduced pyrethrum (extracted from chrysanthemums) and rotenone (extracted from the roots and stems of several tropical and subtropical plant species of the genus Lonchocarpus or Derris) [Miller (21A46)]. 

In fact, a plethora of naturally occurring pyrethrums have been used quite extensively as viabally potent insecticides since the 1800s. A number of potent chemical entities have been successfully isolated from the extract of the flowering portion of the Chrysanthemum plant. Importantly, the plants grown in Kenya (East Africa) contain upto 1.3yo pyrethrins. The pyrethrum extracts earn a sizable agricultural revenue for the country. 

The naturally occurring pyrethrums have been used as Insecticides since the 1800s. These compounds are extracted from the flowering portion of the Chrysanthemum plant. The flowers produced In Kenya have, on average, 1.3% pyrethrins. These pyrethrum extracts are a major agricultural product for that country. 

Organophosphorus pesticides have been the insecticides most commonly used by professional pest control bodies and homeowners for the past three decades (Jeannot and Dagnac 2006). Nevertheless, the decision of the US Environmental Protection Agency (EPA) to phase out certain uses of the organophosphate insecticides because of their potentially toxic effects to humans has led to their gradual replacement by other pesticides. Among them, synthetic pyrethroids have been manufactured since 1950 s based upon the structure of natural pyrethrins, which are chemicals with active insecticidal properties in the pyrethrum extract (a mixture of chemicals found in certain chrysanthemum flowers). Pyrethrins are very unstable in the environment, due to oxidation and UV-radiation. 

C.W. Henry III, S.A. Shamsi and I.M. Warner, Separation of natural pyrethrum extracts using micellar electrokinetic chromatography, J. Chromatogr. A, 863, 89-103,1999. 

Fig. 183. Thin-layer chromatograms of ordinary commercially available pyrethrum extracts of different ages (a, 6, c), photographed in short wave UV light [92]. A on silica gel HF254 under normal conditions B in the BN-chamber using continuous development with solvent I (concluded when the butter yellow attained the evaporation zone) C continuous development with solvent II (concluded when the indophenol reached the evaporation zone) Ja jasmoUn Ci cinerin Pypyrethrin ...

In the middle of the 20th century, the synthetic development of DDT and other chlorinated hydrocarbons (C.H.), increased insecticidal activity well beyond that of most natural products. Problems arose with bioaccumulation of C.H. residues in the food chain, human fat tissue, mother s milk, as well as the development of insecticide resistance. It became obvious there were limitations to synthetic technology as well. The modification of a natural product, for example, from chrysanthemum flowers and their pyrethrum extracts (7) to pyrethroids such as allethrin, resmethrin, permethrin (2), and deltamethrin created a model in which insecticides are created from the skeleton of insecticidally active natural molecules. Thus, the avermectin, abamectin, ivermectin family of pesticides originated from compounds produced by the soil bacterium, Streptomyces avermitilis (5), and the commercially successful chloronicotinyl insecticides, though not derived from nicotine, are chemically related 4). Both pyrethroids and chloronicotinyls are currently used commercially as termiticides. We have previously provided a detailed review of natural products as pesticidal agents for control of the Formosan subterranean termites, Coptotermes formosanus Shiraki (5). 

Essig, K. Zhao, Z. Method development and validation of a high-performance liquid chromatographic method for pyrethrum extract, J.Chromatogr.Sci., 2001, 39, 473-480. [pyrethrins cinerin jasmolin ... 

The use of natural products as pesticides to control pests has a long history. For example, nicotine-based preparations and pyrethrum extracts have proved valuable for certain applications and they differ little in their mode of use from conventional insecticides. From a regulatory standpoint, they merit a similar approach to safety assessment. However, in recent decades approaches to pest control strategies have undergone radical changes. 

For assay extract abc)ut 40 g with hexane for eight hours in a Soxhlet apparatus, repeat the extraction for a further four hours with a fresh quantity of solvent and evaporate the solvent from the combined extracts before applying the abo e method for pyrethrum extract. 

Pyrethrum extract 22 7 5 Moderate resistance-some visual change (discoloration/crazing/ checking) occurs ... 

R. Senior White, House spraying with DDT and with pyrethrum extract compared First results, Journal of the Malaria Institute of India, 6, 83, 1945. 

In early research, the dried and powdered flower heads of Chrysanthemum cinerariaefolium were referred to as pyrethrum or insect powder. Pyrethrum extract, on the other hand, referenced a solvent extraction of the flower heads. Some of the earlier pyrethrum sprays included mixtures of petroleum oils, coal-tar creosote oil, naphthalene, pine oil, pine tar oil, and para-dichlorobenzene." Common constituent groups of the pyrethrum extract were described in the Pyrethrum Blend FEK-99 (Shrader Laboratories, Detroit, MI), including pyrethrins (68.2%), hydrocarbons (15.1%), terpenes (8.5%), high molecular weight hydrocarbons (7%), and other inerts (1.2%) (Figure 15.2). 

D. R. MaciVer, Constituents of pyrethrum extract. In Pyrethrum Flowers Production, Chemistry, Toxicology, and Uses, J. E. Casida and G. B. Quistad (eds.), Oxford University Press, New York, p. 108, 1995. 

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