Chemical characterization and acaricide potential of essential oil from aerial parts of Tagetes patula L. (Asteraceae) against engorged adult females of Rhipicephalus sanguineus (Latreille, 1806)

Molecular detection of haemophilic pathogens reveals evidence of Candidatus Mycoplasma haemobos in dogs and parasitic ticks in central China

Background

In addition to Mycoplasma haemocanis and Candidatus Mycoplasma haematoparvum, a few hemoplasma species that mainly infect other livestock have been detected in dogs. ‘Candidatus Mycoplasma haemobos’ (Ca. M. haemobos) has been found in a variety of animals in China. The present study was aimed to investigate the occurrence of ‘Ca. M. haemobos’ infections in dogs and ticks collected from the Henan province, China.

Results

Overall, 55 dog blood samples and 378 ticks on skins were collected from anemic and healthy dogs, and these samples were subjected to PCR, sequence analysis, and identification. The results showed that Haemaphysalis longicornis (266) and Rhipicephalus (Boophilus) microplus (112) were the only two parasitic ticks on dogs. Molecular detection revealed that 163 M. haemocanis, 88 ‘Ca. M. haemobos’ and 32 Anaplasma platys positive amplicons could be amplified from dogs, H. longicornis and R. (B.) microplus. In addition, co-infections (M. haemocanis + A. platys and ‘Ca. M. haemobos’+ A. platys) could be also detected.

Conclusions

To the best of our knowledge, this is the first molecular evidence of ‘Ca. M. haemobos’ natural infection in dogs and tick species identified as H. longicornis and R. (B.) microplus from China.

Traditional uses, Phyto-chemistry and pharmacological activities of Tagetes Patula L

ETHNO-PHARMACOLOGICAL RELEVANCE

Tagetes patula L. an important medicinal plant of Asteraceae family is worldwide distributed and reported for its folkloric use in various disorders like skin, eye problems, injury and stomach issues by different communities of China, Nepal, India, Bangladesh and Pakistan.

AIM OF THIS REVIEW

The present review has focused the ethnomedicinal and traditional uses of T. patula with special reference to Asian countries. Chemical constituents and pharmacological aspects of T. patula was explored. After reading the review the researchers may able to find new insights to further investigate this plant.

REVISION OF LITERATURE

Google scholar, PubMed, and Science direct, were the major search engines used to get relevant information based on articles and books.

RESULTS

and Discussion: The ethno-botanical aspects were recorded, the pharmacological aspects like antioxidant, anti-inflammatory, antimicrobial, anti-parasitic and anti-diabetic potentials evaluated both in vivo and in vitro is described. The toxicity or allergic manifestation with the use of the plant is also a section in the article. It is a rich source for thiophene derivatives, flavonoids, carotenoids, terpenes and terpenoids. Various gaps were pointed out for researchers that need to be investigated.

CONCLUSION

Various traditional uses have been reported in Asian countries that need to be scientifically investigated in depth and several pharmacological activities have been reported for the T. patula but more detailed and mechanism-based studies linked to a particular lead compound need to be targeted in future.

Insecticidal activity of marigold Tagetes patula plants and foliar extracts against the hemipteran pests, Lygus hesperus and Bemisia tabaci

The western tarnished plant bug, Lygus hesperus Knight (Hemiptera: Miridae) and the whitefly, Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) are key hemipteran pests of numerous crop plants throughout the western United States and Mexico. Management in the U.S. currently relies on only a few insecticides and is threatened by the evolution of resistance. New chemistries or alternative management strategies are needed to reduce selection pressure on current insecticides and enhance control. Here, we investigated the bio-insecticidal toxicity of the French marigold, Tagetes patula Linnaeus (Asterales: Asteraceae), against both L. hesperus and B. tabaci. Assays indicated significantly reduced survival of both pest species on T. patula plants, and in diet incorporation assays containing aqueous and methanolic marigold foliar extracts. Mortality was concentration-dependent, indicating the presence of one or more extractable toxicants. These data suggest that T. patula plants have insecticidal constituents that might be identified and developed as novel alternatives to conventional chemical treatments.

Evaluation of Tagetes patula (Asteraceae) as an ecological alternative in the search for natural control of the cattle tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae)

The cattle tick Rhipicephalus microplus is a great sanitary problem and causes huge losses to livestock, being a vector of important diseases. The aim of this work was to verify the action of plant-derived material obtained from Tagetes patula on the life cycle of R. microplus, as well as to analyze the action of these extracts on ovary cells of engorged females. In the Adult Immersion Test, the crude ethanolic extract (Tp_EtOH) showed an efficacy of 99.2% (LC₅₀ = 18.60 mg mL^-1). From the repellency test, it was found that both the Tp_EtOH and essential oil were 100% efficient on the larval stage. In addition, in the Larval Package Test, a mortality of 98.37% was obtained with Tp_EtOH (LC₅₀ = 3.798 mg mL^-1). From the microscopic analysis of ovary cells, morphological changes in the chorion and cytoplasm of oocytes were observed, with vacuolization around the germinal vesicle and disorganization of the pedicular cells, suggesting an interference in the normal embryogenic formation of the larvae. These results demonstrate that T. patula extracts interfere at all stages of development of the ixodid, from eggs to adults forms, and have a pronounced repellent effect. In addition, the results of the cytotoxicity assays performed on keratinocytes, as well as previous information on oral and dermal acute toxicity (LD₅₀ > 4000 mg kg^-1), attest that T. patula can be a safe alternative for ectoparasitic control, representing an alternative for development of a formulation used to help control populations of ticks in the field.

Tagetes spp. Essential Oils and Other Extracts: Chemical Characterization and Biological Activity

Tagetes (marigold) is native to America, and its cultivation currently extends to other countries in Africa, Asia, and Europe. Many species of this genus, such as T. minuta, T. erecta, T. patula, and T. tenuifolia, are cultivated as ornamental plants and studied for their medicinal properties on the basis of their use in folk medicine. Different parts of the Tagetes species are used as remedies to treat various health problems, including dental, stomach, intestinal, emotional, and nervous disorders, as well as muscular pain, across the world. Furthermore, these plants are studied in the field of agriculture for their fungicidal, bactericidal, and insecticidal activities. The phytochemical composition of the extracts of different Tagetes species parts are reported in this work. These compounds exhibit antioxidant, antiinflammatory, and enzyme inhibitory properties. Cultivation and the factors affecting the chemical composition of Tagetes species are also covered. In the current work, available literature on Tagetes species in traditional medicine, their application as a food preservative, and their antimicrobial activities are reviewed.

Insecticidal activity of an essential oil of Tagetes patula L. (Asteraceae) on common bed bug Cimex lectularius L. and molecular docking of major compounds at the catalytic site of ClAChE1

Emerging resistance to insecticides has influenced pharmaceutical research and the search for alternatives to control the common bed bug Cimex lectularius. In this sense, natural products can play a major role. Tagetes patula, popularly known as dwarf marigold, is a plant native to North America with biocide potential. The aim of this work was to evaluate the biological activity of T. patula essential oil (EO) against adult common bed bugs via exposure to dry residues by the Impregnated Paper Disk Test (IPDT) using cypermethrin as a positive control. We selected the enzyme acetylcholinesterase as a target for modeling studies, with the intent of investigating the molecular basis of any biological activity of the EO. Chemical analysis of the EO was performed using gas chromatography coupled to mass spectrometry (GC-MS). Additionally, oral and dermal acute toxicity tests were performed according to Organization for Economic Cooperation and Development (OECD) guidelines. The sulforhodamine B assay (SRB) was performed to verify the cytotoxicity of EO to HaCaT cells. The EO eliminated 100 % of the bed bugs at 100 mg mL^-1 with an LC₅₀ value of 15.85 mg mL^-1. GC-MS analysis identified α-terpinolene, limonene, piperitenone, and piperitone as major components of the mixture. Molecular modeling studies of these major compounds suggested that they are acetylcholinesterase inhibitors with good steric and electronic complementarity. The in vitro cytotoxicity evaluation revealed a LC₅₀ = 37.06 μg mL^-1 and in vivo acute toxicity showed an LC₅₀ >4000 mg kg^-1, indicating that the EO presents low risk of toxic side effects in humans. The T. patula essential oil components provide a promising strategy for controlling bed bug populations with low mammalian toxicity. These findings pave the way for further in vivo studies aimed at developing a safe and effective insecticide.

Comparative analysis of spermatids of Rhipicephalus sanguineus sensu lato (Ixodidae) and Ornithodoros rostratus ticks (Argasidae): morphophysiology aimed at systematics

The phylogenetic relationships among tick species (Acari: Ixodida) have been revisited by several researchers over the last decades. Two subfamilies, Rhipicephalinae (Ixodidae) and Ornithodorinae (Argasidae), deserve special attention. The male reproductive system morphology, as well as the ultrastructure of the germ cells, may provide important information for phylogeny and systematics of metazoan groups, with spermatozoa exhibiting characters that can be used for this purpose. With that information in mind, this study aimed at evaluating, through a comparative analysis, the morphology of the male reproductive systems and germ cells of ticks species Rhipicephalus sanguineus and Ornithodoros rostratus. In order to do that, histology and scanning electron microscopy techniques were used. The results have shown that despite the similarities in the general morphology of the male reproductive system among studied Ixodida so far, there are morphological differences among the species studied herein, mainly the U-shaped testis (ancestral character) in O. rostratus and the pair testes (derived character) in R. sanguineus, and the general morphology of germ cells (spermatids V). Besides that, the morphological changes observed during the spermiogenesis appear to be different between the species studied here, probably characterizing the two families considered. The data generated in this study showed the importance of comparative internal morphology studies, mainly in regard to spermatology, despite the morphological data obtained herein not being enough to product a cladogram (sperm cladistics), it was already possible to observe clear differences among families Argasidae and Ixodidae in regard to the organization of their male reproductive systems and concerning the external morphology of spermatids. Data yet to be obtained through transmission electron microscopy techniques will allow the application of spermiocladistics and spermiotaxonomy as tools for tick systematics.

Antifungal, antiradical and cytotoxic activities of extractives obtained from Tagetes patula L. (Asteraceae), a potential acaricide plant species

Tagetes patula L. shows a complex chemical composition, ranging from glycosylated flavonoids and thiophenes in extracts until terpenoids in the essential oil. In the present study, due to this rich flavonoidic constitution, its antioxidant potential was determined, having shown values of antiradical percentage superior to reference compounds, mainly the extracts prepared with flowers. Previous studies performed emphasized the acaricide potential of T. patula and thus, the present study aimed to verify the action of extractives obtained from aerial parts on growth of entomopathogenic fungi related to biological control of brown dog tick Rhipicephalus sanguineus and the action against pathogenic fungi closely associated with pets. None of the samples inhibited the growth of strains of Beauveria bassiana or Metarhizium anisopliae, enabling feasible future studies of synergism on acaricide activity of formulations containing fungi and extracts. The antimicrobial activity of ethanolic extract of flowers (FlEtOH70%) against Microsporum canis and Trichophyton rubrum was significant (193.3 μg/mL and 253.9 μg/mL, respectively), as well as ethanolic extract from aerial parts (APEtOH70%) against T. rubrum (312.5 μg/mL). In order to ensure the safety of a topical formulation containing the extractives of T. patula, the cytotoxic potential of these samples were tested in murine macrophages cells. At higher concentrations all extracts were quite lethal, with IC50 ranging from 210.96 μg/mL to 468.75 μg/mL for APEtOH70% and FlEtOH70%, respectively. These results suggest that the application of a product containing T. patula extractives in the control of ticks could be used, at principle, only on the environment.