PHYTOCHEMICAL AND ANTIMICROBIAL ANALYSIS OF DICHLOROMETHANE-METHANOL LEAVES EXTRACT OF Cymbopogon citratus (POACEAE) AGAINST SELECTED BACTERIA AND FUNGAL PATHOGENS

Abstract

ABSTRACT The increasing incidence of microbial resistance to existing antimicrobial agents has intensified the search for novel therapeutic alternatives. This study evaluated the phytochemical composition and antimicrobial activity of a dichloromethane–methanol leaf extract of Cymbopogon citratus (Poaceae). Fresh leaves of C. citratus were collected from Lejja, Nsukka Local Government Area, Enugu State, Nigeria, and authenticated. One kilogram of the leaves was air-dried at 29–35 °C for three weeks, pulverized, and extracted by cold maceration using a 1:1 mixture of methanol (2.5 L) and dichloromethane (2.5 L) for 72 h with continuous agitation. The extract was filtered and concentrated in vacuo at room temperature to obtain the dry extract. Qualitative and quantitative phytochemical analyses were carried out using standard procedures. The antimicrobial activity of the extract was evaluated in vitro against nine human pathogenic microorganisms obtained from the clinical stock of the Department of Pharmaceutical Microbiology and Biotechnology, University of Nigeria, Nsukka, using agar well diffusion and broth microdilution methods. Phytochemical analysis revealed the presence of total phenolics (1897.84 ± 0.09 mg/100 g), alkaloids (476.67 ± 0.07 mg/100 g), terpenoids (203.36 ± 0.02 mg/100 g), flavonoids (119.00 ± 0.03 mg/100 g), reducing sugars (32.61 ± 1.02 mg/100 g), tannins (16.25 ± 0.05 mg/100 g), and steroids (4.77 ± 0.00 mg/100 g), while glycosides and saponins were absent. The extract exhibited antimicrobial activity against Bacillus cereus and Aspergillus flavus. A minimum bactericidal concentration (MBC) of 12.5 mg/mL was recorded against B. cereus, while a minimum fungicidal concentration (MFC) of 25 mg/mL was observed against Candida albicans. These findings demonstrate that the dichloromethane–methanol leaf extract of C. citratus possesses appreciable antimicrobial activity and is rich in bioactive phytochemicals with therapeutic potential.