Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Determination of Inhibitory Action of Allamanda Leaf Extracts Against Some Important Plant Pathogens

S.MASUDUZZAMAN
Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh, Bangladesh

M. B.MEAH
Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh, Bangladesh

M. M. RASHID
Bangladesh Rice Research Institute, Regional Station, Sonagazi, Feni, Bangladesh

Abstract/ Executive Summary:

Allamanda leaf extract and separated compounds were studied to determine their inhibitory efficiency against Phomopsis vexans, Fusarium sp, Rhizoctina solani, Sclerotiurn rolfsii and Phytophthora capsici. Four concentrations of the extract namely 1:1, 1:2, 1:3 and 1:4 were used. Extract at 1:3 concentration completely inhibited mycelial growth of P. vexans while other three concentrations were also near completely inhibitory. No concentration showed good performance to inhibit mycelial growth of Fusarium sp. But all concentrations completely inhibited the growth of mycelia of R. solani. Higher concentration (1:1, 1:2) completely inhibited S. rolfsii whereas lower concentration (1:3, 1:4) arrested its growth to some extent. Incase of P. capsici, though 1:3 concentration completely inhibited mycelial growth but other three were also promising. For separated compounds, compound 1 and 3 completely inhibited the growth of P. vexans, the other one was not so much promising. In case of Fusarium sp and R. solani, compound 3 showed partial inhibition, but the same compound completely inhibited the growth of S. rolfsii and P. capsici. Water extract showed better performance compared to separated compounds which indicated that some of the essential compounds for the inhibitory action might have been removed during preparation of extracts in other solvents

Keywords: Allamanda, Leaf extracts, Compounds, Plant pathogens, Efficiency

Location: Bangladesh Agricultural University , Mymensingh

Start Date: 00-12-2005

End Date: 00-11-2006

Program Area: Pest Management

Commodity: Extract (plant, seed)

Objectives:

To determine the specificity of the inhibitory action of compound (s) in allamanda extract against five important plant pathogens

Methodology:

The experiment was conducted at the IPM Laboratory, Department of Plant Pathology and Chemistry Laboratory, Department of Chemistry, Bangladesh Agricultural University (BAU), Mymensingh during December 2005 to November 2006. Allamanda leaves were collected from BAU campus, mixed with equal amount of water, grinded in mortar and finally sieved through muslin cloth to obtain 1:1 solution. Dilution to 1:2, 1:3 and 1:4 was done simply by adding water. Allamanda leaves collected from BAU campus were dried and powdered as far as possible by mortar and pestle. One hundred grams of powdered leaves were taken and 200 ml methylene chloride was added to it. The mixture was kept over night at room temperature (25±2⁰C). The mixture was then shaken for two hours in a flask shaker, afterwards filtered through cheese cloth followed by filtration through filter paper Whatman No. 1. Some important compounds in allamanda seemed to be unstable so they decompose readily. For this reason, at first allamanda leaf extract was made under normal temperature. They were extracted by refluxing in low boiling solvents like methylene chloride. For preparation of refluxing extract 50 g of dried and powdered allamanda leaves were taken in a thimble, added 200 ml methylene chloride in the thimble. This was done by Soxlet’s apparatus in a water bath keeping the temperature at 40±2⁰C. These extracts were partially concentrated and used for testing against Phomopsis vexans, Fusarium sp, Rhizoctina solani, Sclerotiurn rolfsii and Phytophthora capsici. TLC of these reflux extracts was done and Rf values of the colored and colorless spots were determined. Thin layer chromatographic (TLC) technique was employed for the identification of a number of compounds present in the extracts. TLC of the extracts were made by using different solvents and mixed solvents. A number of spots were seen for different compounds. Their Rf values were determined. A chromatographic column is a long glass tube having 100 cm length and 12 cm breadth and packed with particles of stationary phase Silica gel (0.063-0.200 mm). The space between the particles was completely filled with a non polar solvent hexane which moves under the influence of gravity and pass out at the bottom through the porous support. The column was irrigated with the mobile phase until the desired components of the mixture eluted or separated on the column. The flow rate depends on the dimensions of the column. About 250 ml moving solvent was added above the stationary phase and 200 ml elute was collected in equal volumes by means of a fraction collector. The number of the fraction may range up above thirty. The elute was placed in a water bath to remove the solvent and a small residue was collected. TLC of this residue was made by using different solvents and mixed solvents. The sequences of solvents used in column were 1) Hexane, 2) Benzene, 3) Ethyl acetate and 4) Methylene chloride. The sequence of mixed solvents used in column were a) Hexane:Benzene = 3:1, b) Hexane:Benzene = 1:1, c) Hexane:Benzene = 1:3, d) Benzene:Ethyl acetate = 3:1, e) Benzene:Ethyl acetate = 1:1, f) Benzene:Ethyl acetate = 1:3, g) Ethyl acetate:Methylene chloride = 3:1, h) Ethyl acetate:Methylene chloride = 1:1, i) Ethyl acetate:Methylene chloride = 1:3. Allamanda solution at four concentrations (1:1, 1:2, 1:3 and 1:4) were tested separately against P. vexans, Fusarium sp, R. solani, S. rolfsii and P. capsici in vitro following growth inhibition technique (Meah et al., 2002). Linear growth of the fungus was taken after 24, 48, 72 and 96 hours. Separated compounds of allamanda collected through column chromatography were dissolved individually in a polar solvent methylene chloride. Methylene chloride is a volatile solvent and it has no considerable effect on the growth of the test fungi as checked in vitro following growth inhibition techniques. Bioassay of the compounds was accomplished following the procedure as described for the bioassay of extracts (Meah et al., 2002). Data collected on different parameters were analyzed following Completely Randomized Design (CRD) using statistical computer package program MSTAT. Means were compared with Duncan’s Multiple Range Test (DMRT) (Gomez and Gomez, 1984).

Source of Information: J Agric Rural Dev 6(1&2), 107-112, June 2008, ISSN 1810-1860

Article Link (Online Journal):

Funding Source:

Total Budget (Tk.) :

Achievement/Findings:

Allamanda water extract and separated compounds displayed differential inhibitory action against five plant pathogenic fungi. Water extracts of allamanda leaves exhibited higher inhibitory action against five pathogens than separated compounds. It indicates that some of the components essential for the inhibitory action might have been removed during the preparation of extracts in other solvents, even though allamanda water extracts and separated compounds proved having antifungal properties and a potential source of biological control of plant pathogens. The future research should focus separate the active compound in adequate amount through column chromatography or any other easiest direct method and determine the structure of active compound for commercial formulation of botanical fungicide.

Knowledge Management: Journal