W Rizvi., M Rizvi, R Kumar, A Kumar, I Shukla, M Parveen
antibacterial activity, ficus lyrata, flavonoid, triterpenoid
W Rizvi., M Rizvi, R Kumar, A Kumar, I Shukla, M Parveen. Antibacterial Activity of Ficus lyrata -An In vitro Study. The Internet Journal of Pharmacology. 2009 Volume 8 Number 2.
The semitropical climate of India serves as an excellent environment for abundant bacterial growth. Adding to it the large human host population and the easy availability of the entire gamut of antibiotics over the counter, we face not only rampant bacterial infection but also an enormous problem of escalating drug resistance to known antimicrobial drugs.
In such a situation indigenous plants serve as invaluable sources of new antimicrobial agents (1). In the present study we assessed Ficus lyrata (
Material And Methods
The study was conducted in the Departments of Microbiology, Pharmacology, J.N. Medical College and the Department of Chemistry Aligarh Muslim University, Aligarh, U.P., India.
Plant Moraceae (Ficus lyrata) leaves were collected from University campus and authenticated by Prof. Wazahat Hussain in the department of Botany. A voucher specimen has been deposited in the department no. 215
The structure of pure compounds Ursolic acid (FL-1) and Acacetin-7-O- neohesperidoside. (FL-2) were elucidated on the basis of UV, IR, IH-NMR.
Both gram positive and gram negative bacterial isolates were tested against the plant extracts and isolated pure compounds.
Gram positive strains:
Gram negative strains:
The inoculum size was adjusted to 0.5 Mc Farland for each of these strains before performing disc diffusion assay. The plates were incubated for 24 hours at 37oC. The antibacterial activity was interpreted according to the zones of inhibition produced around the impregnated discs measured to the nearest millimeter. An inhibition zone of 12 mm or more was considered to indicate good antibacterial activity.
Determination of MIC:
The MIC’s were determined for all strains which showed significant zones of inhibition. MIC was performed using the two fold serial dilution method with saline at a final concentration ranging from 5120 mg/L to 0.025 mg/L. Each extract and isolated compound was tested in duplicate. The bacterial suspension was used as positive control and sterile saline as negative control. Two control plates prepared under the same conditions but without the plant extract were included in every MIC determination as a quality control measure. An overnight broth was prepared by picking several identical colonies. The inoculum when applied to the plate with a steers replicator device contained 103 to 104 colony forming units/spot. The plates were incubated overnight at 37oC. The MIC was determined as the lowest concentration of antibiotic inhibiting visible growth after 18-24 hours. One to three colonies or a faint haze was considered a negative result.
Disc diffusion assay : The antibacterial properties of aqueous and alcoholic extracts of
Both FL-1 and FL-2 showed improved results in the disc diffusion assay as compared to the crude extract
_ Zone of inhibition of > 12 mm was taken as significant
FL-1 : Ursolic Acid, FL-2 : Acacetin-7-O- neohesperidoside.
. It is important to note that the zones of inhibition of Methicillin resistant and ESBL producing strains increased to beyond the significant cut off of 12mm in case of FL-1. Significant increase in zones of inhibition were also noticed against
Determination of MIC
MIC values were obtained against the strains which showed significant zones of inhibition (> 12mm) around the discs impregnated with the plant extracts and pure compounds. As expected the MIC’s of the aqueous extract were lower than the alcoholic extracts. The MIC’s of aqueous extracts of
The MIC’s of
With ever increasing momentum in the quest for newer antimicrobial agents, to counteract the spiraling bacterial drug resistance plants are being increasingly explored in many parts of the world. These plants may offer a new source of potential activity against infective microorganisms (8,9). We studied the antibacterial properties of
It is interesting to note that the aqueous /alcoholic extract was selectively active against some Gram positive and some Gram negative bacteria.
To identify the active principle responsible for the antibacterial activity we screened the isolated pure compounds (FL-1 – FL8) from
Our results show that Ursolic acid and Acacetin-7-O- neohesperidoside contributes significantly to the antimicrobial activity of the crude extract of
We acknowledge Miss Priyamvada Raghav and Dr. Onkar Singh for their technical help in our research work.