ANTIMICROBIAL EFFECTS OF EXTRACTS AND MICROORGANISMS FROM POST-FERMENTED LOCUST BEAN (PARKIA BIGLOBOSA JACQ.) ON SOME PATHOGENIC MICROORGANISMS

Abstract

Parkia biglobosa is a nutritious source of food since it is rich in protein and has some beneficial health components. Fermented locust bean (FLB) seed was obtained from three different locations and microorganisms associated with it were isolated. Aqueous and n-hexane extract from it were assayed for antimicrobial activity against pathogenic microorganisms using standard microbiological procedures. Furthermore, the microorganisms isolated from the beans were evaluated for growth antagonistic activity on the pathogenic bacteria. The most susceptible bacterial pathogens to the extracts were used in vivo to determine their effects on the kidney and liver of albino rats. Fermented locust bean bacterial counts ranged from 22.00±2.33 (×105cfu/g) to 37.33±2.40 (×106cfu/g), while the fungal counts ranged between 4.66±0.33 and 9.33±0.88 (×103sfu/g). The microorganisms isolated include Bacillus spp, Lactobacillus spp, Staphylococcus spp, and Aspergillus spp. The phytochemicals present are as follows: flavonoids (19.37±0.53; 12.30±0.23mg/100g), phenol (41.90±0.10; 33.75±0.03mg/100g), saponin (16.65±0.15; 0.00), alkaloids (22.90±0.06; 17.65±0.43 mg/100g), steroids (6.95±0.06 mg/100g; 0.00), cardiac glycosides (3.30±0.06; 1.20±0.00 mg/100g) for n-hexane and aqueous extract of fermented locust bean respectively. Some of the bioactive compounds present in the n-hexane fraction of the sample are 1,3 dimethyl-p-xylene, p-Cymene, azulene, 2-methyl-Naphthalene, 1,2,4 trimethyl Benzene, and ricinoleic acid. Bacillus subtilis, one of the isolates from the sample was observed to have the highest antagonistic activity against pathogenic organisms especially Enterobacter aerogenes (30.00±0.57mm) and Aeromonas hydrophilia (29±0.57mm). The n-hexane fraction of fermented locust bean inhibited Pseudomonas aeruginosa, Klebsiella pneumoniae and Shigella dysenteriae at 2.50mg/ml with mean zones of inhibition (2.00, 3.00 and 4.00mm) respectively and at 20mg/ml Klebsiella pneumoniae had the highest mean zone of inhibition of 14.00±0.23mm. Methicillin- resistant Staphylococcus aureus was more susceptible to the aqueous extract of the bean at 5.00, 10 and 20mg/ml respectively. There was significant decrease in the packed cell volume (PCV) of rats infected with Klebsiella pneumoniae and treated with n-hexane extract of FLB and an increase in the PCV, haemoglobin (HB), white blood cell (WBC), and red blood cell (RBC) of rats infected with Aspergillus flavus and treated with the aqueous extract of FLB, rats infected with Enterobacter aerogenes and antagonized with Staphylococcus saprophyticus from FLB, rats infected with Aeromonas hydrophilia and antagonized with Bacillus subtilis from FLB as compared to the uninfected. Lymphocytes increased in rats infected with Klebsiella pneumoniae and antagonized with Bacillus megaterium (62.00±0.57), Aeromonas hydrophilia antagonized with Bacillus subtilis (62.00±0.57) as compared to the uninfected (55.00±0.57).