---
title: "Antimicrobial activity and phytochemical profile of Rumex abyssinicus root extracts"
id: "plos-one-8-in-vitro-antimicrobial-potential-and-phytochemical-analysis-of-root-extracts-of"
canonical_url: "https://medichelpline.com/clinical-feed/plos-one-8-in-vitro-antimicrobial-potential-and-phytochemical-analysis-of-root-extracts-of"
content_type: "clinical_feed_article"
specialty: "Pharmacology"
source_name: "PLOS ONE (Medicine)"
source_url: "https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0358267"
published_at: "2026-09-11T14:00:00.000Z"
evidence_level: "Journal Feed"
license: "CC-BY-NC-4.0 / Informational Use"
---
# Antimicrobial activity and phytochemical profile of Rumex abyssinicus root extracts
## Provenance & Clinical Metadata
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- **Specialty:** [Pharmacology](https://medichelpline.com/clinical-feed/pharmacology.md)
- **Primary Source:** PLOS ONE (Medicine)
- **Source URL:** [Original Journal Publication](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0358267)
- **Published At:** 2026-09-11T14:00:00.000Z
- **Evidence Rating:** Journal Feed
## Executive GIST (TL;DR)
- Study evaluated in vitro **antimicrobial** activity and phytochemical composition of root extracts of **Rumex abyssinicus**, a medicinal plant used in southern Ethiopia. - Roots were collected from Chencha, Arba Minch, taxonomically authenticated and deposited in the National Herbarium. - Dried root powder was extracted using six solvents of differing polarity; stock solutions prepared at 100 mg/mL and stored at −20°C. - Antimicrobial testing used agar well-diffusion against ATCC bacterial strains, clinical bacterial isolates and fungi; MICs determined by tube dilution. - For phytochemical profiling, root powder was refluxed with **acetonitrile** (1:10 w/v) and analyzed by reverse-phase HPLC coupled with mass spectrometry (RPHPLC-MS). - Statistical analysis used one-way ANOVA with post hoc comparisons; significance at p < 0.05. - Extracts showed measurable antimicrobial effects: bacterial inhibition zones 11–25 mm and fungal zones 9–24 mm; MIC range 12.5–100 mg/mL. - Major compounds identified by RPHPLC-MS included **emodin** (30%), **chrysophanol** (18%), **physcion** (16%), helminthosporin (12%), citreorosein (11%) and emodic acid (8%). - Antimicrobial potency varied by solvent and extract concentration, with generally stronger activity against bacteria than fungi. - Findings support the traditional use of R. abyssinicus roots for treating infectious conditions and provide a chemical basis for observed antimicrobial effects.
## Clinical Analysis & Structured Key Points
In vitro antimicrobial potential and phytochemical analysis of root extracts of Rumex abyssinicus from southern Ethiopia | PLOS One Browse Subject Areas ? Click through the PLOS taxonomy to find articles in your field. For more information about PLOS Subject Areas, click here . Article Authors Metrics Comments Media Coverage Reader Comments Figures Figures Abstract The escalating challenge of antimicrobial resistance require a continuous search for novel compounds with therapeutic potential. The approach of linking traditional practices and knowledge with evidence-based preclinical studies can help minimize the resource-intensive process of drug screening. Rumex abyssinicus is an important plant species used in Ethiopian traditional medicine, and this study aims to conduct a phytochemical analysis of root extracts of R. abyssinicus and determine its antimicrobial activity. R. abyssinicus roots were extracted in six solvents of different polarities. Agar well-diffusion assays of the extracts were performed against type culture bacterial strains, clinically bacterial isolates, and fungi, while the tube dilution method was used to determine the minimum inhibitory concentration of the extracts. The ground root powder was refluxed with acetonitrile (1:10 w/v) and analyzed using reverse-phase high-performance liquid chromatography combined with mass-spectrometry. A one-way analysis of variance followed by post hoc multiple comparisons was performed, and differences were considered statistically significant at p < 0.05. The root extract of R. abyssinicus showed antimicrobial activity against type culture bacteria and clinical isolates, and fungi. Extraction with different solvents yielded extracts with varying antimicrobial activities. The extracts showed a varied range of antimicrobial activities against the test organisms, with inhibition zones of 11–25 mm for bacteria and 9–24 mm for fungi. The MIC range fell between 12.5 and 100 mg/mL. The phytochemical analysis revealed the presence of major compounds such as emodin (30%), chrysophanol (18%), physcion (16%), helminthosporin (12%), citreorosein (11%) and emodic acid (8%) which are envisaged to have functional roles in chemical defense against the tested organisms. The susceptibilities of the tested bacteria and fungi varied depending on the type of solvent used for extraction and extract concentration. Enhanced antimicrobial activities were observed against the entire panel of bacteria compared to those against the test fungi. The results support the traditional use of R. abyssinicus for treating infectious diseases. Citation: Ameya G, Manilal A, Abdulkadir M, Gelana T, Sabu KR (2026) In vitro antimicrobial potential and phytochemical analysis of root extracts of Rumex abyssinicus from southern Ethiopia. PLoS One 21(9): e0358267. https://doi.org/10.1371/journal.pone.0358267 Editor: Zheng Yuan, China Academy of Chinese Medical Sciences Institute of Chinese Materia Medica, CHINA Received: May 16, 2026; Accepted: August 29, 2026; Published: September 11, 2026 Copyright: © 2026 Ameya et al. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability: All data are in the manuscript and/or supporting information files. Funding: The author(s) received no specific funding for this work. Competing interests: The authors have declared that no competing interests exist. Introduction The irrational use of antimicrobial agents and the resulting spread of antimicrobial resistance present considerable challenges to the modern healthcare system [ 1 ]. Antimicrobial resistance is now recognized as a silent pandemic of the 21st century [ 2 ]. An urgent need to develop novel antimicrobial agents exists against the backdrop of rising antimicrobial resistance worldwide. Increasing resistance among bacterial and fungal pathogens is diminishing the efficacy of currently available regimens and poses a substantial threat to global public health [ 3 ]. More than ten thousand patients die each day as a result of infections caused by drug-resistant bacteria [ 4 ]. Beyond its health implications, AMR imposes a heavy economic burden, resulting in losses of billions of dollars annually [ 5 ]. Besides, conventional antimicrobial drugs are often associated with adverse effects, and their limited accessibility in low-income settings has driven research towards safer and more affordable alternatives derived from medicinal plants [ 5 , 6 ]. Traditional medicines serve as an alternative option and continue to play an effective role in disease prevention and management in many regions. The sources of traditional medicines, generally plants, remain integral to healthcare and nutrition globally, especially in developing countries where such formulations constitute a primary component of healthcare systems [ 7 ]. Historically, plant-derived medicines have been extensively utilized to manage diverse diseases, and a considerable proportion of modern therapeutics are derived from natural product leads [ 8 , 9 ]. The genus Rumex (Polygonaceae) has been extensively used in traditional medicine for the treatment of constipation, inflammation, diarrhoea, wounds, jaundice, skin disorders, tumours, and infections [ 10 ]. The genus comprises approximately 200–250 species of annual, biennial, and perennial herbs that are distributed worldwide, particularly in the Northern Hemisphere [ 11 ]. Rumex abyssinicus is a perennial herb native to the Arabian Peninsula and East Africa, where it is commonly known as “Dhangaggoo” (in Afan Oromo) or Embuacho (in Amharic) in Ethiopia. It has long been used in traditional medicine for the treatment of wounds, diarrhea, dysentery, stomach ache, pharyngitis, typhus, rabies, and inflammatory disorders in both humans and livestock [ 11 ]. In Ethiopia, the root of R. abyssinicus is widely applied topically for wound healing by traditional healers across several regions. Despite its widespread use in ethnomedicine for treating infections and inflammatory conditions, further studies are required to identify its chemical constituents and elucidate their relationship to its medicinal value [ 12 ]. Some of the previous studies have demonstrated that R. abyssinicus exhibits significant antioxidant, antimicrobial, anti-inflammatory, and antiviral activities, including activity against influenza A virus [ 13 ]. Phytochemical analyses indicate that flavonoids and coumarins are among the major bioactive constituents of the plant [ 14 ]. Moreover, R. abyssinicus has been reported as a potent inhibitor of urease, an enzyme implicated in several pathological conditions [ 15 ]. So far, no study has been conducted in the study area using reverse-phase high-performance liquid chromatography to analyze root extract of the R. abyssinicus and evaluate their antimicrobial activity against a wide range of pathogenic microorganism . In this study, we specifically focused on investigating the antimicrobial properties and conducting a phytochemical analysis using reverse-phase high-performance liquid chromatography of root extracts of R. abyssinicus , which is commonly used by the local community. Materials and methods Root sample collection The root samples of R. abyssinicus were collected from Chencha, Arba Minch. The plant material was well characterized in the Flora of Ethiopia [ 16 ], and the plant material was identified by botanist Garuma Gerbaba Chemeda (PhD) and deposited in the National Herbarium of Addis Ababa University (GG. 28). Chencha is located in the Gamo Gofa Zone, 37 km north of Arba Minch, Ethiopia. Chencha is located at 6°15′N 37°34′E with an elevation of 2,732 m above sea level, providing a cool and relatively moist environment compared with the surrounding lowland areas. The area is predominantly a rural highland district, inhabited mainly by a community that largely depend on subsistence agriculture and long-established traditional practices involving medicinal plant. Average temperatures typically range from 15°C to 22°C, and annual precipitation is estimated to be between 1,000 and 1,600 mm. These environmental conditions support dense vegetation and create favorable habitats for a wide diversity of plant species, including a rich diversity of medicinal plants which are widely used by local communities as part of their traditional healthcare system [ 17 , 18 ]. Study design This study employed an integrated in vitro pre-clinical experimental design. The crude root extracts of R. abyssinicus were evaluated for their antibacterial and antifungal activities using agar well-diffusion assays and determination of minimum inhibitory concentrations (MICs). Collection and extraction of R. abyssinicus roots The R. abyssinicus plant material was taxonomically authenticated by a qualified plant taxonomist. The collected roots were chopped into small pieces, thoroughly washed under running tap water, rinsed twice with sterile distilled water, and oven-dried at 40°C. The dried material was ground into a fine powder. An amount of 100 g of powder was then soaked separately in 1,000 mL of each solvent for 30 minutes and placed on an orbital shaker at 100 rpm for 24 hours at room temperature. The extracts were then filtered using a sterilized Whatman No. 1 filter paper, and the solvents were removed using a rotary vacuum evaporator at 40°C (Yamato RE 801, Japan) with a round-bottom flask fitted with water condenser. The filtrate obtained were concentrated under reduced pressure in a rotary evaporator at 40°C. After appropriate adjustments and standardizations, the ratios of the respective solvents to the weight of the crude extracts were determined. The color of the obtained extract varied depending on the solvent used for extraction. The resulting residues were weighed and reconstituted in respective solvents to obtain a stock concentration of 100 mg/mL and stored at −20 °C until further use [ 19 , 20 ]. For reverse-phase high-performance liquid chromatography-mass spectrometry (RPHPLC-MS) analysis, the above-mentioned procedure was performed to obtain the extract using acetonitrile as the solvent. Culture and maintenance of test microorganisms The antimicrobial activities of root extracts were evaluated against multiple panels of microorganisms. The first panel consisted of pure cultures of ATCC standard organisms ( Staphylococcus aureus , Salmonella enterica , Klebsiella pneumoniae, and Escherichia coli ), procured from the Ethiopian Public Health Institute. The second panel consisted of clinically isolated bacteria, including WHO-priority bacterial pathogens: methicillin-resistant Staphylococcus aureus (MRSA), extended-spectrum β-lactamase (ESβL) producing E. coli, piperacillin-resistant Pseudomonas aeruginosa (PRP) [ 17 ], and diarrheagenic clinical isolates of Shigella dysenteriae . The third panel consisted of clinically isolated fungi ( Candida albicans, Penicillium sp. , Aspergillus flavus, and A. niger ). All clinical isolates were obtained from Arba Minch General Hospital and were transported in triple-layer packaging under aseptic conditions. Bacterial isolates were maintained on nutrient agar, while fungal isolates were maintained on Sabouraud dextrose agar (SDA). Subculturing was performed regularly, and cultures were stored at 4°C until use. All experiments were conducted under appropriate biosafety conditions, with appropriate disinfection procedures. Agar well-diffusion assay Antibacterial and antifungal activities were evaluated using Mueller–Hinton agar (MHA) and SDA, respectively, following the Clinical and Laboratory Standards Institute guidelines [ 21 ]. A standardized 0.5 McFarland suspension of each test organism was evenly spread on the agar surface. Diffusion wells of approximately 6 mm diameter were prepared using a sterile 200 µL pipette tip (yellow), and 20 µL of each extract at a concentration of 50 mg/mL was added separately to each well. The respective solvents served as negative controls. Inoculated Petri plates were incubated at 37°C for 24 h for bacteria and 48 h for fungi [ 22 ]. Determination of minimum inhibitory concentrations The antibacterial activities of root extracts were evaluated by determining the minimum inhibitory concentrations using the tube dilution technique with nutrient broth. Two-fold serial dilutions of each extract, prepared in the respective solvents, were made to produce concentrations ranging from 1.56 to 100 mg/mL. The initial tube contained a mixture of double-strength nutrient broth and the root extract suspension, from which subsequent serial dilutions were prepared. Each diluted extract was aseptically inoculated with bacterial cultures adjusted to the turbidity of a 0.5 McFarland standard and incubated at 37 °C for 24 hours. Following incubation, the lowest concentration that showed no visible bacterial growth was recorded as the MIC. Control tubes containing nutrient broth inoculated with the test organisms, with and without the solvent used for extraction, were also included [ 17 , 23 ]. The MIC determination procedures were performed in accordance with the CLSI guidelines [ 21 ]. In the case of fungal isolates, MICs were determined by the agar dilution method. Stock solutions of the crude root extracts were mixed with sterile molten Mueller–Hinton agar and Sabouraud dextrose agar, cooled to approximately 45 °C. Two-fold serial dilutions were then prepared to achieve final concentrations ranging between 1.56 and 100 mg/mL, as in the case of bacterial isolates. The resulting agar–extract mixtures were poured into sterile Petri dishes and allowed to solidify. Each plate was inoculated with a fungal suspension standardized to a 0.5 McFarland turbidity and incubated at 37 °C for 48 hours. The MICs were identified as the lowest concentrations of the extracts that completely inhibited the visible growth of the tested fungi; SDA plates containing the fungus with and without the extraction solvent, served as controls [ 17 , 23 ]. Reverse-phase high-performance liquid chromatography The ground root powder was refluxed with acetonitrile (1: 10 w/v) was analyzed using reverse-phase high-performance liquid chromatography (RP-HPLC) combined with mass-spectrometry (MS) (Waters Alliance 2695). The negative ionization mode (ESI 10–40 eV) was selected to identify the fragments produced using a nonpolar Waters symmetry C18 column (250 X 4.6 mm; 5.0µm). The mobile phase consisted of an acetonitrile-water mixture (80:20 v/v) buffered to pH 4.5 with acetate buffer and trifluoroacetic acid, applied isocratically at ambient temperature. The analysis was conducted with a flow rate of 1 ml/minute and a pressure of 4000 psi, utilizing an injection volume of 45 µL for the analyte, which was prepared at a concentration of 1 µg/mL in an 80:20 v/v acetonitrile-water mixture [ 24 ]. Quality control All reagents and culture media were checked for their expiration dates before use. Extracts and inoculated media were stored at 2–8 °C; laboratory procedures strictly adhered to the in-house standard operating procedures for pre-analytical, analytical, and post-analytical quality assurance procedures. The agar well diffusion assay were done in triplicate to minimize measurement bias. Data processing and statistical analysis All agar diffusion assay experiments were conducted in triplicate; data were presented as the mean ± standard deviation (SD), and statistical analysis was performed using SPSS version 25. One-way analysis of variance (ANOVA), followed by post-hoc multiple comparison tests, was used to evaluate differences among groups. Statistical significance was set at P < 0.05. Ethics statement Ethical approval for this study was obtained from the College of Natural and Computational Sciences, Addis Ababa University, by Gemechu Ameya. This study does not involve human subjects or human tissues; rather, it involves only isolated pathogenic microorganisms. For the clinically isolated bacterial and fungal test organisms, the sources were de-identified and were not disclosed; only the isolated microorganisms were used in the study. All procedures were conducted in accordance with institutional ethical standards, standard laboratory protocols, and relevant microbiological research guidelines. Results Characteristics of root extracts The crude root extracts obtained using acetone, chloroform, ethyl acetate, ethanol, methanol, and water exhibited noticeable differences in extraction yield and physical appearance. The extracts varied in color from light yellowish-brown to dark brown, with differences in consistency ranging from low viscous to viscous or resinous masses. The methanol, ethanol, and aqueous extracts generally appeared darker and more viscous, whereas the chloroform and ethyl acetate extracts were lighter in color with relatively less viscous consistency. The acetone extract exhibited an intermediate appearance. Differences were also observed in texture and odor among the extracts. Agar well diffusion assays against bacteria The antimicrobial activity of R. abyssinicus root extract varies considerably depending on the solvents used, with the ethanol extract demonstrating the relatively highest and broadest activity across the tested bacterial strains. The acetone extract exhibited relatively consistent antimicrobial activity across the different test organisms compared with the other solvent extracts. In contrast, the antimicrobial activities of the ethyl acetate and ethanol extracts varied considerably depending on the test organism. The aqueous extract demonstrated the lowest antimicrobial activity against most of the test organisms at the same extract concentration ( Fig 1 ). Download: PNG larger image TIFF original image Fig 1. Overall antimicrobial activity of different solvent extracts against selected test organisms based on agar diffusion assay. https://doi.org/10.1371/journal.pone.0358267.g001 The ethanolic extracts showed considerable antimicrobial activity against the drug-resistant clinical isolates, including MRSA (21 mm), EsβL-EC (17 mm) and PRP (19 mm). This extract produced the largest zone of inhibition (25 mm) against the type culture of K. pneumoniae , which was identified as the most susceptible bacterium, while consistently generating larger inhibition zones against other species. The acetone extract also demonstrated strong antimicrobial activity, particularly against the type culture of S. aureus (23 mm) and K. pneumoniae (23 mm), with no significant difference from the ethanol extract. Moderate activities were observed for the chloroform and ethyl acetate extracts, which produced intermediate zones of inhibition. In contrast, the aqueous extract exhibited significantly lowest activity (P < 0.001), failing to inhibit the growth of most of the tested bacteria species and showing only minimal activity against S. aureus (11 mm). Among the organisms tested, Salmonella enterica appeared to be the most resistant to the organic extracts, consistently recording the smallest inhibition zones, including the lowest observed value of 14 mm for the methanol extract. This was followed by ESβL-EC and PRP, which also showed relatively lower susceptibility to the extracts. Overall, the acetone and ethanol extracts of the R. abyssinicus exhibited the greatest antimicrobial effectiveness, followed by the methanol, chloroform, and ethyl acetate extracts, whereas the aqueous extract showed poor activity ( Table 1 ). Download: PNG larger image TIFF original image Table 1. Antimicrobial activity of R. abyssinicus root extract against type culture and clinical isolate bacteria by agar well diffusion assay. https://doi.org/10.1371/journal.pone.0358267.t001 Antifungal activity of the extract using agar well diffusion assay The antifungal activities of R. abyssini
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