Evaluation of Inhibitory Zone Diameter (IZD) of crude Spondias mombin (Linn.) extracts (root, leaf, and stem bark) against thirty infectious clinical and environmental isolates.

Abstract

The purpose of this work is to evaluate the Inhibitory Zone Diameter (IZD) of crude Spondias mombin extracts against thirty infectious clinical and environmental organisms. The root, leaf and stem-bark of S. mombin were harvested and air-dried. The dried S. mombin was milled into powdered form using manual grinder. Powdered S. mombin (1kg) each of the different S. mombin parts was extracted with 3 L of 70% (v/v) ethanol, ethyl acetate and distilled water for 72 h at room temperature. The antimicrobial assay of crude Spondias mombin extracts on the test bacteria was determined by the agar diffusion method. A 0.1 ml of 1:10,000 dilutions (equivalent to 106 cfu /ml) of fresh overnight broth culture of the test bacteria was seeded on molten Mueller-Hinton agar plate. Using a sterile cork borer of 6 mm diameter, equidistant wells were bored on the agar. One millimeter of the various re-suspended extracts (7.5, 15, 30 and 60 mg / ml) was introduced into the wells. Ofloxacin (5 µg) was used as control. The plates were then incubated at 37°C for 24 to 48 hours. Antifungal assay of crude root, leaf, and stem bark of Spondias mombin extracts were determined using Agar well diffusion method. A 5- day old fungal culture on potato dextrose agar (PDA) was flooded with 2 ml of sterile distilled water containing 3% glycerol. The spores were harvested by scraping with a sterile inoculating loop. Sterile PDA plates were inoculated with 0.1 ml of the fungal spore suspension using the spread plate technique. Five wells were bored on the potato dextrose agar (PDA) plates using a 6 mm sterile cork borer. The plates were allowed to stand on the bench for 1 hour before incubating at 25°C for 5 days. Diameter of zones of growth inhibition was then measured in millimeter with a vernier caliper. Aqueous leaf extract of S.mombin had the zone of inhibition of 23 mm against B. cepacia at 60 mg/ml. The aqueous stem bark and root of S. mombin extracts at 60 mg/ ml had the highest zone of inhibition of 23 mm, each against C. koseri and K. ozaenae. However, the aqueous Stem bark extract of S.mombin did not show any antibacterial activity against M. abscessus neither did the aqueous root extract show antibacterial activity against E. coli. This study revealed that the plant extracts possessed antibacterial and antifungal activities against some highly infectious clinical and environmental pathogens which justified their use in ethno- medicine for treatment of infectious diseases.