S Patel, N Venugopalan, S Pradeep
antibacterial activity, blotter, screening, seed-borne fungi
S Patel, N Venugopalan, S Pradeep. Screening For Antimicrobial Activity Of Weeds. The Internet Journal of Microbiology. 2006 Volume 4 Number 1.
The efficacy of leaf extracts (aqueous and ether-water extracts) of
The use of higher plants and their extracts to treat infections is an age-old practice. Traditional medicinal practice has been known for centuries in many parts of the world. Ayurveda, the science of life, prevention and longevity is the oldest and most holistic medical system available on the planet today. Herbal medicines are gaining growing interest because of their cost effective and eco-friendly attributes [Dwivedi,1998].
Even though pharmacological industries have produced a number of new antibiotics in the last three decades, resistance to these drugs by microorganisms has increased. Hence, more studies pertaining to the use of plants as therapeutic agents should be emphasized, especially those related to the control of antibiotic resistant microbes.
In recent years much attention has been given to nonchemical systems for seed treatment to protect them against seed-borne pathogens. Plant extracts have played significant role in the inhibition of seed-borne pathogens and in the improvement of seed quality and field emergence of plant seeds [Nwachukwe, 2001].
Contrary to the synthetic drugs, antimicrobials of plant origin are not associated with many side effects and have an enormous therapeutic potential to heal many infectious diseases.
If this medicinal or antimicrobial property resides in a weed that will be an added advantage. The present investigation is therefore, undertaken to test the efficacy of some of the common weed extracts against the bacterial pathogens like
Materials and Methods
Some of the common weeds were collected from different parts of Davanagere District, Karnataka, India and are easily identified, as they are common weeds. Table 1 gives the list of plants used.
Bacterial and fungal cultures used were obtained from NCIM, Pune.
a) For 20% aqueous extract preparation, 2g of plant material was crushed in 10ml. of sterile water and it was filtered using Whatman Filter Paper No.1. The filtrate was collected in sterile tube and was stored by refrigeration
b) For 10% Ether-water solvent extraction 1:3 mixture of ether and water was prepared and 30ml of this solvent was used. [Harbrne, 1998].
Preliminary screening for antibacterial activity
In the preliminary screening was done by well in agar method i.e, the bacterial cultures were spread on the agar surface using sterile cotton swab. Then a well of 0.5cm. was made in the medium using sterile cork borer, 100µl. of each 20% aqueous and 10% ether-water weed extract were transferred into separate wells and plates were incubated at 37 C for 24 hours [Onkar, 1995].
Standard antibiotics like Penicillin, Streptomycin, Sulfasomidine were also tested against each test organism. Each disc of penicillin had concentration of 10 units/disc, streptomycin – 10µg /disc and Sulfasomidine – 300µg/disc.
Screening for antifungal activity
Results and Discussion
Preliminary studies with the aqueous and ether-water extracts of weeds
Among the plant extracts tested
Table3 shows the results of invitro antifungal activity of the extracts. The extracts of
Table4 shows the results of invivo seed testing of extracts. Extracts of
Authors like to thank Sri G M Lingaraju, Secretory, GMIT for providing facilities for the work.
Seema J Patel
Dept. of Biotechnology
GM Institute of Technology