Establishment of antitick efficacy of a phytoformulation prepared from Annona squamosa leaf extracts for the management of acaricide resistant tick infestations on cattle.

To combat the problem of acaricide resistance in ticks, efforts have been made to develop eco-friendly herbal acaricides which are safe for animal use with no possibilities of evoking environment and residual toxicity. In the present study, the acaricidal properties of a commonly available plant, Annona squamosa have been established to develop a novel antitick phytoformulation using leaf extract, suitable solvents and emulsifier for managing resistant tick infestations in animals. The quality control of the safe and stable phytoformulation using Rutin as a major constituent was maintained by HPTLC profiling. Several phytformulations (A-E) were prepared and formulation 'C' is identifried as the most effective showing 52.5-75% antitick activity against in vitro treated resistant strains of R. microplus (IVRI-IV and V) with 33.8-40.2% inhibition of oviposition while 65-85% mortality against multiacaricide resistant field populations. The phytoformulation provided 70.4% efficacy after first larval challenge in experimentally infested animals. The field efficacy of the formulation in different multilocational field trials was 68.53-77.8%. The detail antitick efficacy of the formulation along with safety and stability are explained as a component of antitck technology to manage resistant tick problem in livestock.

In vitro acaricidal properties of Semecarpus anacardium fruit and Datura stramonium leaf extracts against acaricide susceptible (IVRI-I line) and resistant (IVRI-V line) Rhipicephalus (Boophilus) microplus.

In an attempt to identify plants having anti-tick properties, the 95% ethanolic and 50% hydro-ethanolic extracts of the fruits of Semecarpus anacardium and leaves of Datura stramonium were evaluated against reference tick lines of Rhipicephalus (Boophilus) microplus. The 95% ethanolic extracts of S. anacardium and D. stramonium caused 50% and 20% mortality, respectively, within 72 h of treatment by adult immersion test. The LC90 value of the ethanolic fruit extract of S. anacardium was determined as 13.5% (CI 12.05-15.12). The extract was also found efficacious (73.3%±3.3%) against the multi-acaricide-resistant IVRI-V line of R.(B.) microplus. The S. anacardium extract significantly affected the reproductive physiology of treated ticks by inhibiting the oviposition and was found safe. The HPTLC fingerprinting profile revealed the presence of pyrocatechol as a marker compound. The acaricidal property of S. anacardium against chemical acaricide-resistant R. (B.) microplus was discussed.

Identification of potential plant extracts for anti-tick activity against acaricide resistant cattle ticks, Rhipicephalus (Boophilus) microplus (Acari: Ixodidae).

To develop an eco-friendly tick control method, seven plant extracts were prepared using 50 and 95% ethanol and evaluated for acaricidal activity against cattle tick, Rhipicephalus (Boophilus) microplus. The adult immersion test was adopted for testing different extracts. Based on 72 h screening criterion, 95% ethanolic extracts of Datura metel fruits and Argemone mexicana whole plant were found effective showing more than 50% mortality of treated ticks. The 95% ethanolic extracts of D. metel fruits and A. mexicana whole plant exhibited acaricidal and reproductive inhibitory effects on treated ticks. The LC90 values of D. metel and A. mexicana extracts were determined as 7.13 and 11.3%, respectively. However, although both the extracts were found efficacious against deltamethrin-resistant IVRI-4 and multi-acaricide resistant IVRI-5 lines of R. (B.) microplus, they caused less mortality than treated ticks of the reference IVRI-I line. Phytochemical studies indicated the presence of alkaloids and glucosides in D. metel fruits and alkaloids, terpenoids, flavonoids and phenolics in A. mexicana whole plant extracts. The results indicated that these botanicals may play an important role in reducing the use of chemicals for tick control and possibly to manage resistant tick population in environment friendly manner.

Acaricidal properties of Ricinus communis leaf extracts against organophosphate and pyrethroids resistant Rhipicephalus (Boophilus) microplus.

Indian cattle ticks have developed resistance to commonly used acaricides and an attempt has been made to formulate an ecofriendly herbal preparation for the control of acaricide resistant ticks. A 95% ethanolic extract of Ricinus communis was used to test the efficacy against reference acaricide resistant lines by in vitro assay. In in vitro assay, the extract significantly affects the mortality rate of ticks in dose-dependent manner ranging from 35.0 ± 5.0 to 95.0 ± 5.0% with an additional effect on reproductive physiology of ticks by inhibiting 36.4-63.1% of oviposition. The leaf extract was found effective in killing 48.0, 56.7 and 60.0% diazinon, deltamethrin and multi-acaricide resistant ticks, respectively. However, the cidal and oviposition limiting properties of the extract were separated when the extract was fractionated with hexane, chloroform, n-butanol and water. The HPTLC finger printing profile of R. communis leaf extract under λ(max.) - 254 showed presence of quercetin, gallic acid, flavone and kaempferol which seemed to have synergistic acaricidal action. In vivo experiment resulted in 59.9% efficacy on Ist challenge, however, following 2nd challenge the efficacy was reduced to 48.5%. The results indicated that the 95% ethanolic leaf extract of R. communis can be used effectively in integrated format for the control of acaricide resistant ticks.

TLC densitometric quantification of picrosides (picroside-I and picroside-II) in Picrorhiza kurroa and its substitute Picrorhiza scrophulariiflora and their antioxidant studies.

Picroside-I and picroside-II are known bioactive metabolites in Picrorhiza species. In the present study a simple, precise method has been established for the simultaneous determination of picrosides (picroside-I and picroside-II) in two different Picrorhiza species, P. kurroa and P. scrophulariiflora. This method was also validated for accuracy, precision, robustness, limit of detection and quantification, repeatability and recovery, according to International Conference of Harmonization guidelines. Separation and quantification was achieved by HPTLC using as the mobile phase chloroform-methanol (88:12, v/v) on precoated silica gel 60F(254) aluminum plates. Densitometric determination was carried out at wavelength λ(max) 254 nm in UV absorbance mode. Comparative study also revealed that picroside-I and picroside-II are higher in P. scrophulariiflora than P. kurroa. Picroside-I content was found to be 1.258 and 1.611%, and picroside-II was estimated as 0.481 and 0.613% in P. kurroa and P. scrophulariiflora, respectively. Antioxidant potential of these two Picrorhiza species was also studied using DPPH. At a concentration of 0.1 mg/mL the scavenging activities of P. kurroa and P. scrophulariiflora were found to 37.70 and 34.30%, respectively.

In vitro and in vivo efficacy of Acorus calamus extract against Rhipicephalus (Boophilus) microplus.

To develop a environment friendly control measure against cattle tick, Rhipicephalus (Boophilus) microplus, medicinally important plants were identified and extracts were prepared. Twelve 95% ethanolic, thirteen 50% hydroethanolic and nine hot water extracts were prepared and tested against laboratory reared homogenous colony of R. (B.) microplus. Amongst the 34 extracts, 26 extracts showed no mortality within 72 h of application while 12.0 ± 4.9% to 35.0 ± 9.6% mortality of treated ticks was recorded in other extracts. Of the effective extracts, the extract prepared from rhizome of Acorus calamus proved highly efficacious and 100% final mortality within 14 DPT was recorded. The LC85 value of the extract was determined as 11.26. In vivo experiments confirmed the efficacy of the extract up to 42%, and repeat application was required after 7 DPT. The extract was found safe and no reaction was observed when animals were treated with 50% of the concentration, which was five times of the concentration used for in vivo studies. The possibility of using the extract for the control of cattle tick is discussed.