ASSESSING THE PHYTOCHEMICAL CONTENTS AND ANTIMICROBIAL ACTIVITY OF BITTER LEAF (VERNONIA AMYGDALINA) ON MICRO-ORGANISMS

Andrew Omachi Department of Chemistry, Kogi State College of Education, Ankpa. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History Received: 10 February 2021 Final Accepted: 16 March 2021 Published: April 2021

Medicinal plants have assumed the basis of traditional medicine and have proven effective in human health care across the world. There is a growing interest in the role of complementary and alternative medicines to treat various illnesses. The continued consumption of antibiotic with little or no impact on bacteria have negatively affected health care delivery. Bitter leaf (Vernonia amygdalina) is a popular shrub belonging to the family Asteraceae and a perennial shrub commonly cultivated as a homestead vegetable and fodder tree in various parts of Nigeria. The current study was conducted to assess the phytochemical constituents and antimicrobial activity of bitter leaf on Candida albicans, Pseudomonas aeruginosa and Staphylococcus aureus. The result of the phytochemical analysis conducted on the root and stem bark of V. amygdalina revealed the presence of alkaloids, tannin, steroids, flavonoids, phenol, and saponins. However, it was found that tannins and phenol were mainly deposited in the plant's stem bark.Also, the antimicrobial analysis conducted revealed that S. aureus was more vulnerable to the ethanol, acetone, and hot aqueous extracts of V. amygdalina. while, P. aeruginosa, and C. Albicans showed sensitivity to ethanol and acetone exposure but failed to react to the hot aqueous extracts.The study concludes that the observed biological reactions shown by the aqueous extracts of V. amygdalina corroborate the traditional application of this plant as an alternative antibiotic. trend has continued to attract wide patronage following most conventional antibiotics' ineffectiveness due to the antimicrobial resistance by bacteria.
The growing occurrence of antimicrobial drug resistance by most bacteria has triggered a public health concern(Bennani et al.

Sample Extraction Aqueous Extract
Ten grams of the ground sample of the plant stem bark and leaf were extracted was added to 100ml of sterile distilled. The extraction of the plant's aqueous components was done following the method adopted in (Abdulmalik et al., 2016;Ali et al., 2017).

Phytochemical Screening of V. amygdalina
Phytochemical screening of the V. amygdalina stem bark and root extracts was conducted to ascertain bioactive components such as alkaloids, tannins, saponins, steroids, phenols, and flavonoidsusing the standard qualitative method as previously described by Trease and Evans (1989).

Sterility Test of the Plant Extracts
The plant's extracted constituents were tested for sterility following sterilization by inoculating 1 mL of each extract on sterile nutrient agar incubated at 37°C for 24 hours. Perhaps, the plates were carefully observed for growth.

Standardization of the Bacterial Cell Suspension
McFarland standard was adopted to test for the standardization of the bacterial suspension. Colonies of the tested organism werepicked into a sterile test-tube containing sterile nutrient broth and incubated for one day.

Determination of Antimicrobial Activities
The crude extracts' antimicrobial activity was conducted using the agarwell diffusion method described by (Gashe & Zeleke, 2017) with few modifications. The above table shows the outcome of the aqueous screening conducted on the root and stem bark of V. amygdalina indicates that the plant contains a significant number of alkaloids, tannin, steroids, flavonoids, phenol, and saponins. However, the screening revealed tannins and phenols in the stem bark and not the plant's root.  Table showing the observed zone of inhibition of ethanol extract on V. amygdalina stem bark and root against some pathogenic organisms. Exposing the organisms to the aqueous extract of stem bark for sensitivity revealed the same 8mm diameter of inhibition zone (36.89% and 37.10%), respectively, for C. Albicans and S. aureus. However, P. aeruginosapossessed a minimal 5mm (6.78%) diameter inhibition zone compared to C. Albicans and S. aureus. The test on an ethanol extract of the root shows that S. aureus produced a high diameter of inhibition zone of 7mm (36.26%) while C. albicans produced lower with 3mm (12.45%) diameter of inhibition zone. The table above shows the test organisms' sensitivity parameter when exposed to an acetone extract of V. amygdalina stem bark and root. The result indicated a high diameter of inhibition zones of 15mm for P. aeruginosa and S. aureus (31.36% and 36.10%), respectively, when tested with acetone stem bark extract of V. amygdalina. However, C. Albicans produced a reduced diameter of inhibition zones of 8mm (21.38%). Furthermore, it was revealed that C. Albicans produced an increased diameter of inhibition zones of 7mm (41.19%) when subjected to acetone root extract of V. amygdalina. The organisms were exposed to hot aqueous extract of the plant. Only one pathogenic organism (S. aureus) exhibited a reaction with the 8mm diameter of inhibition zone. Thus, other organisms maintained a resistant position towards the extract.

Discussion:-
The current study was conducted to assess the phytochemical constituents and antimicrobial activity of bitter leaf on Candida albicans, Pseudomonas aeruginosa,andStaphylococcus aureus. The result of the phytochemical analysis conducted on the root and stem bark of V. amygdalina revealed the presence of alkaloids, tannin, steroids, flavonoids, phenol, and saponins. However, it was found that tannins and phenol were mainly deposited in the plant's stem bark. Thus, the study is consistent with previous studies (