Phytochemical and in-vitro antibacterial assessment of selected wild edible plants from southwestern Ethiopia

Abstract

Background: Wild edible plants (WEPs) play a very crucial role in food security and traditional medicine, especially in the regions where access to modern healthcare and nutrition is scarce. Ethiopia is the country rich in biodiversity, with various WEPs having nutritional and medicinal potential. However, the broader utilization of these plants remains limited due to insufficient scientific evidence. Thus, screening the physicochemical and phytochemical contents and assessing the antibacterial properties of WEPs is important for standardizing their therapeutic applications and enhancing their integration into modern health care systems. Objective: The study is aimed at screening the phytochemical constituents and assessing the in-vitro antibacterial activity of selected wild edible plants from southwestern Ethiopia. Methods: A mixed-method approach combining observational and experimental study designs was employed. The study was conducted in the Seri Shewa and Burussa kebeles, selected based on a preliminary desk review. Key informant interviews and multi-criteria decision analysis (MCDA) were used to identify and prioritize WEPs with medicinal significance. The selected WEPs samples were collected, dried and powdered. An extraction was performed using methanol, ethanol, and acetone solvents. Physicochemical properties, including extractive and ash content, were tested. Screening of phytochemicals was conducted using standard conventional qualitative assays. Antibacterial activity was assessed using agar disc diffusion and broth dilution methods against S. aureus and E. coli. Extracts were tested at concentrations ranging from 10 mg/mL to 100 mg/mL, with gentamicin as a positive control and 2% dimethyl sulfoxide (DMSO) as a negative control. Data analysis were conducted using SPSS and Microsoft Excel 2010. Result: A total of 22 WEPs were identified as medicinally important, and M. arcuata and P. aquilinum, exhibiting the highest MCDA scores (scoring 9 out of 10 criteria), were selected. Physicochemical tests revealed that M. arcuata had higher extractive yields in water (36.267%) and ethanol (17.067%) compared to P. aquilinum (16.400% in water and 1.600% in ethanol). Conversely, P. aquilinum resulted in slightly higher ash contents (6.577% total ash, 1.267% water-insoluble ash, and 0.086% acid-insoluble ash) when compared with M. arcuata (5.940%, 1.086%, and 0.056%, respectively). Phytochemical screening confirmed III the presence of alkaloids, glycosides, tannins, flavonoids, saponins, steroids, phenols, terpenoids, quinones, reducing sugars, protein, amino acids, and lipids or oils in M. arcuata, while P. aquilinum lacked only reducing sugars. In antibacterial assays, M. arcuata ethanol and acetone extracts demonstrated significant inhibitory effects against S. aureus, with zone of inhibition 16.20 ± 0.02 mm and 17.23 ± 0.06 mm, respectively, at 100 mg/mL. The minimum inhibitory concentration of the M. arcuata was 25 mg/mL. In contrast, P. aquilinum showed no antibacterial activity at tested concentrations. Conclusion: This study highlights the pharmaceutical potential of M. arcuata, with M. arcuata exhibiting notable antibacterial properties, reflecting its antimicrobial potential. The findings support the ethnomedicinal use of M. arcuata and suggest the need for further research to isolate bioactive compounds for therapeutic applications.