Thumbnail Image

Kerala Veterinary and Animal Sciences University, Wayanad

Browse

2015 - 20173
Reset filters
Subject: Veterinary Pharmacology and Toxicology × End date: 2017 × Start date: 2015 × Thesis Type: Ph.D ×
Reset filters

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    ThesisItemOpen Access
    IDENTIFICATION, ISOLATION AND CHARACTERIZATION OF POTENTIAL ACARICIDAL MOLECULE(S) FROM PLANT EXTRACT AND STUDIES ON THEIR MODE OF ACTION
    (COLLEGE OF VETERINARY AND ANIMAL SCIENCES MANNUTHY, THRISSUR, 2015-09-30) SREELEKHA K. P.; Sanis Juliet
    The present study was conducted to isolate active biomolecule(s) from Blumea mollis plant extract having potent acaricidal activity against R. (B.) annulatus and to study their mode of action. Blumea mollis (D. Don) Merr., Asteraceae family is an annual aromatic herb indigenous to tropical South India. The plant materials were collected from identified phytogeographical zones. The ethanolic extract of different accessions of the plant was assayed for acaricidal activity using adult immersion test and larval packet test. Further, isolation and characterization of bioactive fractions / sub-fractions were performed using standard chromatographic and spectral techniques. The accession CAS 01 of B. mollis was selected as the best accessions with more than 80-100% efficacy against R.(B.) annulatus.The freeze dried crude extract of elite accession of CAS-01 was tested for safety using OECD guidelines. Phytochemical analysis revealed the presence of high content of terpenoids in the accession CAS 01. The hexane fraction was found to be active and HPTLC profiling showed marker concentration comparable to that of ethanolic extract of CAS 01. Phytochemical analysis of hexane fraction revealed the presence of high content terpenoids further confirmed by GC-MS. The GC-MS analysis of active sub-fractions revealed the presence of several components ranging from monoterpenes, diterpenes to sesquiterpenoids. Among the four molecules selected based on their chemical nature and area percent, ethyl palmitate, VP5 and marker compound VP1 elicited the acaricidal activity varying from 95 - 100 %. The histology and transmission electron microscopic analysis of active biomolecules exhibited marked changes comparable to that of synthetic acaricides deltamethrin and amitraz. The β octopamine receptor gene expression studies using whole tick and ovary showed significant down regulation comparable to amitraz in case of VP1 whereas ethyl palmitate and VP5 showed no significant change. Structural analogy results revealed similarity with compounds mediating action through GPCR receptors. The isolated molecules can be used as template for the development of promising acaricides.
  • Thumbnail Image
    ThesisItemOpen Access
    EVALUATION OF ANTITUMOUR PROPERTIES OF SIMAROUBA GLAUCA (‘LAKSHMI TARU’) AND THESPESIA POPULNEA (‘POOVARASU’) IN EXPERIMENTAL MAMMARY TUMOUR MODELS IN RATS
    (COLLEGE OF VETERINARY AND ANIMAL SCIENCES MANNUTHY, THRISSUR, 2017-12-30) ANU G; Usha P. T. A.
    The present study was undertaken to evaluate the antitumour properties of Simarouba glauca (‘Lakshmi taru’) and Thespesia populnea (‘Poovarasu’) in in vitro cancer cell line and in DMBA (7, 12 dimethyl benz[a]anthracene) induced mammary tumours in rats. The crude alcoholic extracts and different fractions of S. glauca leaves and T. populnea bark were screened for their cytotoxic property in MCF-7 human breast carcinoma cell line. Based on the IC50 value, chloroform soluble fractions (CSF) of both S. glauca and T. populnea were found to be superior in cytotoxic action than crude extracts and other fractions, and hence CSFs of both the plants were selected for further in vitro and in vivo studies. In in vitro haemolytic assay, CSF of S. glauca did not produce haemolysis in any of the tested concentrations whereas CSF of T. populnea showed haemolytic activity in a dose dependent manner starting from the concentration 40 µg/mL. Chloroform soluble fractions of S. glauca and T. populnea exhibited a superior in vitro antioxidant effect in a dose dependent manner when compared with vitamin C standard. On phase contrast microscopy and Acridine orange/ ethidium bromide (AOEB) dual staining, MCF-7 cells treated with CSFs of S. glauca and T. populnea exhibited marked morphological and nuclear alterations which were characteristics of apoptosis. DNA ladder assay and TUNEL assay was conducted to detect the apoptotic DNA fragmentation if any, occurred in MCF-7 cells after treatment with the plant fractions. A typical ladder pattern characteristic of apoptosis was not observed in DNA ladder assay whereas, there was an increase in positive reactions noticed in TUNEL assay which indicates an increase in DNA fragmentation after the plant fraction treatments. In acute toxicity study (OECD Guidelines no. 423) in rats, there was no apparent toxic symptoms or mortality observed in both S. glauca and T. populnea treatment groups up to an oral dose of 2000 mg/kg body weight. For in vivo antitumour studies, DMBA induced rat mammary tumour model was used. Experimental study was conducted for 14 days with 12 animals in each group. 154 After treatment with S. glauca and T. populnea CSFs at the dose rates 50 mg/kg and 100 mg/kg, no significant changes were noticed on tumour volume, tumour weight and ratio of tumour weight to body weight. The elevated mean serum LDH levels decreased significantly in the treatment groups on days 7 and 14. When compared with normal control, SOD, CAT and GSH levels were noticed to increase whereas lipid peroxidation level reduced in the mammary tumour tissues after the plant fraction treatments. In AO/EB dual staining, an increased apoptotic and necrotic cell density was observed in both the plant fraction treatment groups in dose dependent manner. After treatment with CSFs of S. glauca and T. populnea, the antiapoptotic gene Bcl2 expression was downregulated both in in vitro and in vivo studies. On histopathological examination of the mammary tumour masses using H & E staining, a progressive reduction in cellularity and apoptotic changes were noticed in the plant fraction treated groups. Thus in the present study, CSF of ethanolic extract of S. glauca leaf and CSF of methanolic extract of T. populnea bark exhibited a dose dependent cytotoxic and antitumour activity both in vitro and in vivo. The plant fractions were effective in inducing apoptotic cell death and may be considered as potent sources for isolating therapeutic molecules for cancer treatment.
  • Thumbnail Image
    ThesisItemOpen Access
    SCREENING AND EVALUATION OF SELECTED HERBAL EXTRACT FOR MANAGEMENT OF OBESITY AND ASSOCIATED METABOLIC DISORDERS
    (COLLEGE OF VETERINARY AND ANIMAL SCIENCES MANNUTHY, THRISSUR, 2015-12-30) J. JOSHUA ALLAN; Usha P.T.A.
    The global prevalence of obesity and its associated metabolic comorbidities, especially dyslipidemia are at present escalating alarmingly, which necessitates urgent implementation of earnest preventive and therapeutic measures. Identifying the medications that target obesity, dyslipidemia and the underlying oxidative stress with less or negligible side effects, hence seem to be an excellent strategy. The present study was undertaken to identify a safe herbal substance possessing anti-obese and anti-dyslipidemic potentials along with targeting the underlying oxidative stress. The plants were shortlisted based on history of food use, usage in daily life, mentioned in texts of Ayurveda for medicinal use, not classified as endangered species and present in normally traded as commodities list. Accordingly, six plant extracts were initially screened for acute oral toxicity and hypotriglyceridemic effect in oral lipid load test. The screening tests indicated aqueous extract of Zingiber officinale rhizome as the safe and potent extract, which was further fractionated to improve the solubility. The fraction showing highest solubility i.e., water soluble fraction of Zingiber officinale extract (WFZE) was further subjected to acute oral toxicity and oral lipid load tests to ensure the safety and efficacy. The WFZE was found to be safe upto 5000 mg/kg body weight in acute oral toxicity study in rat and its triglyceride lowering activity was found to be better than the parent extract. Consequently, WFZE was evaluated for anti-obese and anti-dyslipidemic potentials. The anti-obesity effect of WFZE was established in high fat diet induced obese male rats by the significant reduction in body weight gain, adiposity and triglyceride levels along with the amelioration of metabolic perturbations such as hyperleptinemia, increase in the FFA, glucose and insulin. Moreover, the total hepatic lipids, serum AST and ALT were reduced while atherogenic index and insulin resistance indices such as HOMA and QUIKI were controlled and the severity of histopathological lesions in liver, pancreas and adipose tissue were reduced after treatment with WFZE. In addition, WFZE treatment significantly reduced the oxidative stress induced by high fat feeding as evident from the significant decrease in hepatic MDA and increase in SOD, catalase and glutathione reductase levels, indicating the anti-oxidant potential of WFZE. The anti-dyslipidemic activity of WFZE was further demonstrated in Triton WR-1339 induced and cholesterol cholic acid induced dyslipidemic models. A significant reduction in serum triglycerides and cholesterol levels following the administration of Triton WR-1339 and chronic feeding of cholesterol and cholic acid in rats established the anti-dyslipidemic activity of WFZE. To elucidate the mechanism of action, WFZE was investigated for its activity against pancreatic lipase, which indicated promising pancreatic lipase inhibitory activity in vitro. The findings of the present study suggest that WFZE is a safe, effective therapeutic agent for the management of obesity and dyslipidemia acting via the inhibition of pancreatic lipase and anti-oxidant mechanisms.