IN VITRO ANTIMICROBIAL ACTIVITY OF THE CRUDE EXTRACTS OF COLOCASIA ESCULENTA LEAVES (ARACEAE)

IN VITRO ANTIMICROBIAL ACTIVITY OF THE CRUDE EXTRACTS OF COLOCASIA ESCULENTA LEAVES (ARACEAE)

Meenal S Kubde *, S S Khadabadi, S S Saboo, D S Ghorpade and A J Modi

Department of Pharmacognosy and Phytochemistry, Govt. College of Pharmacy, Kathora Naka, Amravati (MH), India

ABSTRACT

Colocasia esculenta belonging to family araceae popularly knows as “taro”, is very useful medicinal plant described by Charaka as an anti-inflammatory plant. An experiment was carried out to study the antimicrobial activity of chloroform and methanol extract of Colocasia esculenta plant by agar diffusion method. Zone of inhibition produced by chloroform and methanol extract in dose of 20, 10, 5, 2.5, 1.25, 0.625, 0.3125 mg/ml against some selected strains was measured and compared with standard antibiotics tetracycline in dose of 5, 2.5, 0.625, 0.3125, 0.15625, 0.078072 mg/ml.

INTRODUCTION: Colocasia esculenta (araceae) having Taro as local Indian name, was evaluated for preliminary antimicrobial activity. They are edible aroids which are important staple foods in many parts of the world. Within the family Araceae True taro probably originates from the tropical region between India and Indonesia and has been grown in the South Pacific for hundreds of years. The species is thought to be a native of India. The young leaves are rich in Vitamin C, and the roots are rich in starch. It contains thiamine, riboflavin, niacin, oxalic acid, calcium oxalate, sapotoxin and flavones, apigenin and luteolin.

The tubers contain amino acids and proteins. The corms contain the anthocyanins perlargonidin 3-glucoside, cyaniding 3-rhamnoside and cyaniding 3-glucoside. Traditionally it is used to settle the stomach, to prevent swelling and pain and to reduce fever. It is also used as a poultice on infected sores. The leaf juice of the plant is styptic, stimulant and rubefacient, and is useful in internal hemorrhages. The juice of the corm is laxative, demulcent and anodyne. Antiinflammatory activity has been reported ¹.  Antibacterial Activity of Colocasia esculenta was studied against bacterial strains, Pseudomonas testosteroni, Staphylococcus epidermidis, Proteus morganii, Bacillus subtilis, Micrococcus flavus and Klebsiella pneumoniae. The methanolic extract showed inhibitory activity against K. pneumoniae only ².

MATERIAL AND METHOD: Fresh leaves of Colocasia esculenta collected in the month of November to December from Amravati District, Maharashtra. The fresh leaves of Colocasia esculenta were dried under shade & powder in a mixture grinder. The powder leaves packed in a paper bags and stored in air tight container until use. The  Soxhlet  process  was  used  for  the    extraction  of  the  plant  material  with  particular  solvent   choose  according  to  increasing  its  polarity like Chloroform, Methanol . Qualitative phytochemical analysis of all extracts was performed to know chemical constituents of extracts.

Antimicrobial Study: Microorganisms: All the strains of micro- organism were obtained from National chemical Laboratory, Pune. Table 1 is showing Gram-Positive, Gram-negative and fungal microorganisms used for the study.

TABLE NO. 1: GRAM-POSITIVE, GRAM-NEGATIVE AND FUNGAL MICROORGANISMS

Antibacterial Assay: Agar-well diffusion method: The agar diffusion method was used to screen the Antibacterial activity of various extract of leaves of. Colocasia esculenta 0.2 ml of each of the seeded broth containing 10^-7 test organisms was inoculated on the plates of solidified agar and spreaded uniformly. Then 8 wells were cut in the agar layer of each plate with an aluminium bore of 6mm diameter.

In every plate 6 different extracts of concentration 20 mg/ml dissolved in DMSO were added while in 7^th and 8^th well standard tetracycline and control DMSO was added. Then all plates were incubated at 37⁰C ± 1 for 18 hrs. After the incubation period the mean diameter of the zone of inhibition in mm obtained around the well was measured which has been shown in Table 2.

TABLE-2: ZONE OF INHIBITION IN MM (INCLUDING BORE DIAMETER 6MM)

CH: Chloroform extract, ME: Methanol extract, STD: Standard drug

Antifungal assay: Anti-fungal study was carried out through same procedure as used in antibacterial study only difference was media used for antifungal study was Sabouraud dextrose agar media (SDA MEDIUM) ^{3, 4}.

Determination of Minimum Inhibitory Concentration (MIC):

Two fold serial dilution method: The test was carried out individually for different microorganisms with respect to the chloroform, methanol solvent extract which shows effective result on bacteria. This testing was done in the seeded broth by two-fold serial dilution technique. The solutions of different extracts were prepared of concentration 20 mg/ml in DMSO. For both Gram positive and Gram-negative organism a series of 7 assay tubes for concentrations i.e. 20, 10, 5, 2.5, 1.25, 0.625, 0.3125 mg/ml for each extract were used, while standard tetracycline concentration was taken as 5, 2.5, 0.625, 0.3125, 0.15625, 0.078072 mg/ml. One  positive  control  for  each  microorganism  was  prepared  by  adding  nutrient  broth  with  respective  microorganism  inoculums. To each concentration test tube required volume of sterile nutrient broth and inoculums was added and kept for 24 hours incubation at 37⁰C.  After incubation period the growth of microorganism by considering turbidity was measured by using turbidometer ⁵. Results are shown in Table 3.

TABLE 3: RESULTS OF MINIMUM INHIBITORY CONCENTRATIONS

CH: Chloroform extract, ME: Methanol extract, STD: Standard drug

FIG 1: ANTIMICROBIAL AND ANTIFUNGAL ACTIVITY OF DIFFERENT EXTRACTS

RESULTS AND DISCUSSION: Antimicrobial studies by agar well diffusion method has shown that  all  extracts  of  leaves  of Colocasia esculenta has  considerable  anti bacterial  and  antifungal  activity  against  all  microbial  strains. Though all extract were found effective against bacteria and fungi, chloroform extract showed maximum inhibition against Gram –ve bacteria. Methanolic extract showed maximum inhibition against Gram +ve bacteria. MIC of  chloroform  extract  in  average  on  both  Gram +ve  and  Gram –ve  was  found  to  be  5 mg/ml  while  MIC  of  methanol extract  was  found  to  be  2.5   mg/ml. In anti-fungal study chloroform extract showed good anti fungal activity than methanolic extract.  MIC  of  chloroform  extract on  A. niger,  A. flavons,  candida  albicans  was  found  to  be  2.5,  5,  10 mg/ml respectively and  MIC  of  methanol extract  was  found  to  be  5, 10, 10 mg/ml respectively.

REFERENCES:

1. Shah Biren (2007). The anti-inflammatory activity of the leaves of Colocasia esculenta, Saudi Pharmaceutical Journal, v.15: 3-4.
2. Nair R(2005), Antibacterial Activity of Some Selected Indian Medicinal Flora, Turk J Biol 29: 41-47.
3. Dugler Basaran and Gonuz Ahmet(2004) , Anti microbial Activity  of  Certain  Plants used  in  Turkish  Traditional    Asia J Plant Sci, 3(1): 104-107.
4. Lino Apak and Deogracious Olila (2006) , The In-vitro  anti bacterial  activity  of Annona  senegalensis,  Securidacca  longipendiculata  and  Steganotaenia  araliacea-  Ugandan  medicinal    Afr Health sci, 6: 31-35.
5. Parekh Jigna , Karathia Nehal and Chanda Sumitra (2006), Evaluation  of Antibacterial  activity  and  Phytochemical  analysis  of  Bauhinia  Variegata  bark.  Afr J Biom Res, 9:53-56.
   

   ---