Use Of Plant-derived Compounds Research Articles

Exploring the Combined Efficacy of Carvacrol and Friedelin against Multi-Drug Resistant Bacteria in Upper and Lower Respiratory Tract Infections

In the face of escalating antibiotic resistance, the quest for alternative therapeutic strategies against multi-drug resistant (MDR) bacteria has become imperative. This study explores the combined efficacy of carvacrol and friedelin, derived from Nigella seed and Sweet violet extracts, against prevalent MDR bacteria implicated in upper and lower respiratory tract infections. Employing a dose-dependent methodology across a spectrum of bacterial strains—E. coli, S. aureus, P. aeruginosa, and K. pneumonia—our research evaluates the antibacterial potential of these natural compounds in comparison to conventional antibiotic treatments, notably ciprofloxacin. Results demonstrated a significant increase in zones of inhibition with methanolic extracts exhibiting superior activity, particularly against S. aureus and E. coli, suggesting a potent mechanism of action capable of targeting specific bacterial cell structures or metabolic pathways. Notably, at higher concentrations, these extracts outperformed ciprofloxacin, underscoring their potential as viable alternatives or adjuncts in combating bacterial infections. This study not only contributes to the growing body of evidence supporting the use of plant-derived compounds against MDR bacteria but also underscores the urgency for further investigation into their mechanisms, safety, and clinical applications. Through this research, we affirm the significant potential of carvacrol and friedelin as foundational elements in developing new antimicrobial strategies to address the pressing challenge of antibiotic resistance.

The Potential of Phytotherapy In Managing Dyspepsia: A Narrative Review

Dyspepsia, commonly known as indigestion, is delineated as suffering the manifestations of epigastric pain, nausea, burning, or after-meal fullness. The common therapy for dyspepsia, e.g., proton pump inhibitors or histamine-H2 receptor antagonists, has shown some adverse effects, thus, phytotherapy is currently becoming the drug of interest. Phytotherapy, additionally known as herbal medicine or botanical medicinal drug, includes the use of plant-derived compounds to prevent, alleviate, or therapy for diverse ailments. Most medications commonly used in Chinese traditional medicine or Asian folklore drugs contain mixtures of several plant extracts. Twelve clinical trials reported the effect and safety of phytotherapy on gastrointestinal disorders. Taken together, phytotherapy may be considered safe for the management of dyspepsia with close monitoring of the dose and duration of therapy.

Technological strategies for the use of plant-derived compounds in the preservation of fish products.

New approaches to reducing synthetic preservatives in the preservation of foods draw the attention of plant-derived bioactive compounds, especially for application in foods highly susceptible to spoilage, such as fish products. The review presents relevant data from procurement, application, and methodological research trends to investigate the potential effects of plant-derived bioactive compounds on shelf life extension in fish products. The systematization of data allowed observation that the different methods of extraction and application of bioactive plant compounds result in different effects, such as the reduction of lipid oxidation, antimicrobial effects, and maintenance of sensory characteristics, benefiting the extension of shelf life. In general, plant-derived bioactive compounds are an alternative for the preservation of fish products; however, approaches to the composition of the compounds can contribute to the optimization and efficiency of the process from a technical point of view and industrial viability.

Role of Ayurvedic drugs as possible chemo protectors in cancer

Cancer is the leading cause of mortality worldwide. Although substantial progress has been made in the treatment and control of cancer progression, there are still significant flaws and space for improvement. During chemotherapy, a number of unfavorable side effects might arise. Natural therapies, such as the use of plant-derived compounds in cancer treatment, have the potential to lessen negative side effects. A few plant products are now being used to cure cancer. However, there are a slew of plant compounds with promise anti-cancer capabilities in vitro that have yet to be tested in humans. In light of this, Ayurveda, which takes a holistic approach to disease treatment, could be a viable alternative to individual plant isolates in the treatment of cancer. To assess the efficacy of these plant components in treating cancer in humans, more research is needed. The focus of this study will be on the plant-derived chemical compounds that have showed promise as anticancer medicines in recent years, as well as their probable mechanisms of action as chemo protectors as adjuvant to conventional cancer treatment.

Plant Products in the Prevention of Diabetes Mellitus.

The beneficial effect of plants in treating diabetes is not only well-known in traditional medicine but also confirmed in numerous scientific studies. The basic platform for testing the potential antidiabetic activity of traditionally known plants and their bioactive compounds is a set of in vitro, in vivo experiments, clinical trials, and molecular docking studies. Basic assays usually measure enzyme inhibitory activity (α-amylase and α-glucosidase) and other aspects related to diabetes mellitus disease. Recently, the use of plant-derived compounds has proven useful in treating diabetes and reducing complications resulting from high blood sugar levels. The main goal is to establish an action mechanism of plant extracts or active compounds to find new antidiabetic drugs with less toxicological properties. This work aims to collect data and discuss the newest results in the area of plant extracts, compounds, and antidiabetic effects using in vitro, in vivo, and in silico models. The data covered in this review include plant extracts, polyphenols, terpenoids, saponins, phytosterols, and other bioactive compounds, with some of the investigated plants being less known. Isolation of new compounds might be a plentiful source for treatment and prevention of diabetes mellitus. Clinical trials with adequate monitoring give the best results of plants' product efficacy and safety. Many studies have confirmed the importance of patent and use of medicinal herbs in the treatment of diabetes.

In vitro investigation of cytotoxic, antioxidant, apoptosis-inducing, and wound healing properties of endemic Centaurea fenzlii Reichardt extracts.

Cancer is a formidable problem for global health, and the increasing burden necessitates the search for new and alternative treatments and/or approaches. For this reason, any approach to cancer treatment is extremely valuable. Recently, there has been increasing interest in the use of plant-derived compounds in the treatment of cancer. ​Many studies have shown that many of the best-selling anti-cancer drugs are of plant origin. Based on this, the cytotoxic potential of two extracts [C. fenzlii leaf extract (CFL) and C. fenzlii capitula extract (CFC)] from Centaurea fenzlii, a plant species endemic to Turkey, were tested in two different cancer cell lines (DLD1 and ARH77) and a healthy cell line (HUVEC). Cytotoxic effects of the extracts were determined by MTT assay, changes in the mRNA expressions of the apoptotic genes (apaf, bax, bcl2, bcl2l11, casp3, gadd45a and hrk) were determined via the qRT-PCR technique, and the caspase3 enzyme activity was determined. In addition, the capacities of the extracts against invasion and migration were also evaluated. The chemical content and phenolic composition were evaluated via the gas chromatography-mass spectrometry (GC/MS) and high-performance liquid chromatography (HPLC) techniques. As a result, the extracts showed a selective cytotoxic effect in all the cancer cell lines examined, especially the DLD1 colorectal cell line. In addition, it has been determined that the extracts inhibit the invasion and migration of cells. The results of the study reveal that C. fenzlii, which has been found to have acceptable anti-cancer effects, should be investigated with more comprehensive studies.

In-silico characterization of phytochemicals identified from Vitex negundo (L) extract as potential therapy for Wnt-signaling proteins

BackgroundColorectal cancer is the third most diagnosed disease in the world population and current chemotherapy has been used for targeting the cell proliferation and metastasizing ability of tumor cells. Potent chemotherapeutic drugs for colorectal cancer are capecitabine, fluorouracil, irinotecan, etc. which have toxic effects in normal tissues and adverse effects in multiple organs leading to major obstacles in clinical use. The aim of the study is the use of plant-derived compounds that improve the effectiveness of chemotherapeutics with lower and alleviate toxic side effects and reduce the risk of tumor progression.ResultsThe current study is performed using Vitex negundo leaf which has been demonstrated to have positive effects against colorectal cancer. The use of computational approaches will help improve the identification and screening of lead molecules using AutoDock 4.2 and AutoDock Vina. Using computational approaches will help to improve lead identification and screening. Herein, we have retrieved six phytochemicals from published literature and investigated their inhibitory effect with Wnt-associated signaling proteins. Authentication of phytocompounds and Wnt-associated signaling proteins was done using AutoDock.4.2.ConclusionsThe results are screened based on the number of hydrogen bonds, binding energy, and interacting amino acids. The Isoorientin, luteolin, and Chrysophanol get the highest binding energy with target receptors. The binding energy is calculated with all target receptors from the range of − 6.0 to − 8.9 kcal/mol. The In-silico drug likeliness properties are predicted to be the best interacting compounds based on Lipinski Rule of 5 and ADMET analysis. Hence, we propose that Isoorientin, luteolin, and Chrysophanol are the potential inhibitors of Wnt signaling inhibitors, and preclinical studies are needed to confirm the promising therapeutic ability of colorectal cancer.

Roles and Mechanisms of Astragaloside IV in Combating Neuronal Aging.

Aging can lead to changes in the cellular milieu of the brain. These changes may exacerbate, resulting in pathological phenomena (including impaired bioenergetics, aberrant neurotransmission, compromised resilience and neuroplasticity, mitochondrial dysfunction, and the generation of free radicals) and the onset of neurodegenerative diseases. Furthermore, alterations in the energy-sensing pathways can accelerate neuronal aging but the exact mechanism of neural aging is still elusive. In recent decades, the use of plant-derived compounds, including astragaloside IV, to treat neuronal aging and its associated diseases has been extensively investigated. This article presents the current understanding of the roles and mechanisms of astragaloside IV in combating neuronal aging. The ability of the agent to suppress oxidative stress, to attenuate inflammatory responses and to maintain mitochondrial integrity will be discussed. Important challenges to be tacked for further development of astragaloside IV-based pharmacophores will be highlighted for future research.

A comparative study of bacterial activity of allyl isothiocyanate, phenyl isothiocyanate, and 2- (4- hydroxy phenyl) ethyl isothiocyanate using density functional theory

The main objective of this work is to study and compare the antibacterial activity of some isothiocyanate molecules. Isothiocyanates come under the category of sulfur-containing phytochemicals based on their chemical structure. We choose here three isothiocyanate molecules; Phenyl isothiocyanate (PITC), Allyl isothiocyanate (AITC), and 2-(4-hydroxyphenyl) ethyl isothiocyanate (HEITC), and study their properties using the method of Density-Functional Theory (DFT) of B3LYP/6-31G basis type through Gaussian software and compare their anti-bacterial activity. The optimized structure and optimization parameters of these molecules are found using this approach. The HOMO-LUMO analysis is done and the bandgap energy and global descriptive parameters are calculated. The chemical activity of the molecules is studied through ESP (Electrostatic Potential Energy) mapping. The atomic charge values are obtained through Mulliken population analysis. Thermal analysis of the molecules is carried out and the thermal properties are determined. The chemical reactivity of each molecule is studied based on these analyses and thus the anti-bacterial activity of the molecules is compared. This study implicitly signifies the use of plant-derived compounds for the synthesis of antibiotics for human diseases.

The potential of phenolic acids in therapy against snakebites: A review

Ophidism is a serious health problem worldwide and is included in the World Health Organization's (WHO's) list of Neglected Tropical Diseases. Although snakebite envenoming requires emergency treatment, currently the only treatment recommended by WHO is serotherapy, which has some disadvantages such as low access to the rural population, low effectiveness in neutralizing local effects, and high cost. In this context, new alternatives for the treatment of snakebites are required. The use of plant-derived compounds to inhibit the effects caused by snake venoms has been the object of a number of studies in recent years. This review aims to provide an up-to-date overview of the use of phenolic acids with therapeutic application against envenomation by snakes of different species. In this sense, structural analysis in silico and biological activities in vivo and in vitro were reported. The acids were subdivided into derivatives of benzoic and cinnamic acids, with derivatives of cinnamic acids being the most studied. Studies have revealed that these compounds are capable of inhibiting local and systemic effects induced by envenomation, and structural analyses indicate that the acids interact with important sites responsible for the action of toxins. Thus, it was reported that phenolic acids showed antiophidic potential, providing insights for future research to develop complementary drugs for the treatment of snakebites.

Simultaneous Inhibition of SARS-CoV-2 Infectivity by a Specific Combination of Plant-derived Compounds

SARS-CoV-2 pandemic remains a challenge to human health and economy worldwide. Previously we have shown that a combination of active plant-derived compounds and plant extracts can dose-dependently inhibit binding of RBD-spike protein SARS-CoV-2 to the ACE2 receptor and its expression on human alveolar epithelial cells. Here we use eGFP-luciferase-SARS-CoV-2 spike protein pseudo-virions and SARS-CoV-2-RdRp, to show if the antiviral effectiveness of this combination of plant-derived compounds and plant extracts expands to other important key mechanisms of SARS-CoV-2 infection. Or results revealed that this combination of five plant-derived compounds inhibited the attachment of the SARS-CoV-2 pseudo-typed particles with lung hACE2/A549 cells. In addition, it down-regulated the activity of key enzymes known to be crucial for the entry of the SARS-CoV-2 virus, such as TMPRSS2, furin and cathepsin L, but not their expression at protein level. This combination did not affect ACE2 binding to and ACE2 enzymatic activity, but modestly decrease cellular expression of neuropilin-1 molecule and significantly inhibited activity of viral RdRp. This study demonstrates inhibitory effects of this combination on key cellular mechanisms of SARS-CoV-2 infection. The findings further support the use of plant-derived compounds as effective health measures against SARS-CoV-2-caused infection.

Azadirachtin-Based Insecticide: Overview, Risk Assessments, and Future Directions

In the context of the major crop losses, pesticides will continue to play a key role in pest management practice in absence of practical and efficient alternatives; however, increasing awareness regarding environmental and human health impacts of conventional pesticides as well as the development of resistance and cross-resistance reduced their availability and promoted the search for alternative control strategies and reduced-risk pesticides. Among the various alternatives, a drastic re-emergence of interest in the use of plant-derived compounds, called allelochemicals, was noted and demand for an organic product is rising. Currently, azadirachtin, a tetranortriterpenoid derived from the neem seed of the Indian neem tree [Azadirachta indica A. Juss (Meliaceae)], is one of the prominent biopesticides commercialized and remains the most successful botanical pesticide in agricultural use worldwide. Azadirachtin is a powerful antifeedant and insect growth disruptor with exceptional low residual power and low toxicity to biocontrol agents, predators, and parasitoids. This review summarizes the state of the art on key azadirachtin insecticidal activities and risk assessment, identifies knowledge gaps that could serve as the basis for future research direction and highlights limitation in agricultural use and the development of novel strategies by the use of nanotechnology to control its release rate and improve its stability and sustainability.

Zuccagnia punctata Cav. Essential Oil into Poly(ε-caprolactone) Matrices as a Sustainable and Environmentally Friendly Strategy Biorepellent against Triatoma infestans (Klug) (Hemiptera, Reduviidae).

The main strategies against Triatoma infestans (primary vector responsible for the Chagas disease transmission) are the elimination or reduction of its abundance in homes through the application of insecticides or repellents with residual power, and environmental management through the improvement of housing. The use of plant-derived compounds as a source of therapeutic agents (i.e., essential oils from aromatic plants and their components) is a valuable alternative to conventional insecticides and repellents. Essential oil-based insect repellents are environmentally friendly and provide reliable personal protection against the bites of mosquitoes and other blood-sucking insects. This study investigates, for the first time to our knowledge, the potential repellent activity of Zuccagnia punctata essential oil (ZEO) and poly(ε-caprolactone) matrices loaded with ZEO (ZEOP) prepared by solvent casting. The analysis of its essential oil from aerial parts by GC–FID and GC-MS, MS allowed the identification of 25 constituents representing 99.5% of the composition. The main components of the oil were identified as (−)-5,6-dehydrocamphor (62.4%), alpha-pinene (9.1%), thuja-2, 4 (10)-diene (4.6%) and dihydroeugenol (4.5%). ZEOP matrices were homogeneous and opaque, with thickness of 800 ± 140 µm and encapsulation efficiency values above 98%. ZEO and ZEOP at the lowest dose (0.5% wt./wt., 96 h) showed a repellency of 33 and 73% respectively, while at the highest dose (1% wt./wt., 96 h) exhibited a repellent activity of 40 and 66 %, respectively. On the other hand, until 72 h, ZEO showed a strong repellent activity against T. infestans (88% repellency average; Class V) to both concentrations, compared with positive control N-N diethyl-3-methylbenzamide (DEET). The essential oils from the Andean flora have shown an excellent repellent activity, highlighting the repellent activity of Zuccagnia punctata. The effectiveness of ZEO was extended by its incorporation in polymeric systems and could have a potential home or peridomiciliary use, which might help prevent, or at least reduce, Chagas’ disease transmission.

Pepper and Garlic Extracts as an Alternative Treatment to Onychomycosis: AMyth or Truth?

Onychomycosis is a chronic disease ofa nail infection by the fungi. Based on the mode of nail invasion and morphologic patterns, it can be divided into 5subtypes: distal and lateral subungualonychomycosis, proximal subungualonychomycosis, superficial onychomycosis, total dystrophic onychomycosis, and endonyxsubungualonychomycosis.Common pathogens are dermatophytes, non-dermatophyte molds, and yeasts. In recent years, the development of new antifungal agents, such as allylamines and azoles, has provided good treatment options for onychomycosistherapy. There is a growing interest in the use of plant-derived compounds or alternatives to treat dermatophyte infection. Recently, a Chinese web page describing an alternative method for onychomycosis by using garlic and pepper extractswas very popular [Figure 1] [1]. They described 200 cases of onychomycosis patients treated once daily with a mixture of 100g garlic and 20g pepper extracted with 500ml acetic acid for 30 days. They claimed the cure rate was 94.05% and the effective rate was 99.88%. Although it may seem effective, the detailed exact preparation methods, the culture results, and the subtypes of the onychomycosis were not described. The treatment responses also seemed too good to be true. Martin et al. reviewed 7 controlled clinical trials performed to determine the effectiveness of plant extracts against fungal infection [2]. Among them, tea tree oil was the most thoroughly clinically tested. Solanum species and oil of bitter orange preparations were also reviewed. However, there were no researches on garlic or pepper preparation. Till now, there are still no peer-reviewed, double-blind, placebo-controlledclinical trials of garlic or pepper-based preparations used as an alternative treatment method for onychomycosis.

Effect of resveratrol and quercetin on the susceptibility of Escherichia coli to antibiotics.

Activities of plant polyphenols (PPs), resveratrol and quercetin, alone or in combination with four conventional antibiotics against Escherichia coli have been investigated. In medium without antibiotics, both polyphenols caused a dose-dependent growth inhibition. However, pretreatment with resveratrol (40 and 100 μg ml-1) and quercetin (40 μg ml-1) reduced the bacteriostatic effect of kanamycin, streptomycin, cefotaxime and partially of ciprofloxacin. With few exceptions, both PPs also reduced the bactericidal effect of tested antibiotics. Paradoxically, low doses of PPs enhanced the bactericidal effect of kanamycin and partially ciprofloxacin. Compared to quercetin, resveratrol showed a weaker effect on the induction of antioxidant genes and the resistance of E. coli to the oxidative stress generated by hydrogen peroxide treatment. Both polyphenols at high doses reduced membrane potential. Altogether, these findings suggest that the decrease in the bactericidal effect of antibiotics by high doses of polyphenols is mostly due to bacteriostatic action of the latter. In the case of quercetin, the contribution of its antioxidant activity for antibiotic protection may be significant. There is a growing interest in the use of plant-derived compounds to enhance the toxicity of traditional antibiotics. This and other studies show that, under certain conditions, the use of polyphenols as adjuvants may not exert the expected therapeutic effect, but rather to decrease antimicrobial activity of antibiotics.

A Review of the Bioactivity of Plant Products Against Aedes aegypti (Diptera: Culicidae)

Abstract The mosquito Aedes aegypti L. (Diptera: Culicidae) is a disease vector for several pathogens that affect human health worldwide. Therefore, there is a need to produce synthetic chemicals that can effectively control mosquitoes; however, these chemicals can also cause a range of environmental and health problems. In the present review, we compiled all available information from the literature between 2005 and 2018 on plant products that have been used to control A. aegypti and tabulated their modes of action. This review classifies these plant-based products according to their bioactivities (toxicity, repellency, feeding deterrence, and oviposition deterrence) and provides new insights, findings, and patterns of their application. Plants contain a wide spectrum of chemical compounds that can effectively control mosquito populations; therefore, they should be developed to control diseases transmitted by mosquitoes. Plant products are mostly safe for human, animal, and environmental health. Moreover, because of the diversity and low use of plant-derived compounds as insect control agents, mosquitoes have not acquired resistance to them. The present review indicated that the bioactivities of many plant compounds can effectively control A. aegypti in laboratory conditions, and the comprehensive cataloging and classification of natural plant product bioactivities in this review will facilitate the search for new applications of these substances in insect pest control strategies.

Effects of Arthrocen, an avocado/soy unsaponifiables agent, on inflammatory mediators and gene expression in human chondrocytes.

Osteoarthritis (OA) is a chronic joint disease characterized by pain and stiffness. Recently, there has been great interest in the use of plant‐derived compounds and supplements in managing the symptoms of OA. Arthrocen is a plant‐based supplement consisting of avocado and soy unsaponifiable extracts in a 1 : 2 ratio. In an effort to unravel the potential mechanisms of its action on the cellular level, we utilized an in vitro assay to study its effects on cultured human chondrocytes. By pairing this assay with protein arrays on inflammatory markers, RNA‐Seq with downstream pathway analysis, and lipidomics on eicosanoids, we were able to further define its action at the molecular level. Specifically, we found a role for Arthrocen in attenuating the inflammatory response both at the protein and mRNA level. Furthermore, we discovered that Arthrocen diminished prostaglandin E2 (PGE2) levels in response to an inflammatory trigger. Additionally, unlike traditional COX‐2 inhibitors, this response rather specifically attenuated PGE2 levels in the presence of inflammation and without lowering levels of other eicosanoids. This implies that Arthrocen could potentially bring about the reduced pain produced by COX‐2 inhibitors without the known side effects of COX‐2 inhibition.

Activity of myricetin and other plant-derived polyhydroxyl compounds in human LDL and human vascular endothelial cells against oxidative stress.

Studies indicate that oxidative modifications of endothelium and LDL play a preeminent role in atherogenesis; therefore, the preservation of the endothelial antioxidant capacity and the inhibition of LDL oxidation by use of plant-derived compounds are an appealing strategy against several vascular disorders. On this basis, baicalein, eupatorin, galangin, magnolol, myricetin, oleuropein, silibinin and bilobalide were studied against various oxidative conditions. The radical scavenging capacity was analysed using DPPH and ORAC assays. Furthermore, the LDL oxidation was detected by measuring the formation of thiobarbituric acid reactive substances (TBARS) and by monitoring the oxidation kinetics. Further, we used cultured HUVEC to investigate the activities of the polyhydroxyl compounds towards the oxidative stress induced by H2O2. The lowest levels of TBARS were observed in the presence of oleuropein and baicalein, while myricetin, magnolol and eupatorin inhibited these ones to a lesser extent. In addition, oleuropein and myricetin exhibited higher protection in copper-induced LDL oxidation kinetics. However, only myricetin and galangin showed significant protective effects against H2O2 oxidative injury in HUVEC cells. Taken all together the results indicate myricetin as the most active agent among the selected plant-derived polyhydroxyl compounds, with prominent capacities against ox-LDL and ROS production in HUVEC.

The assessment of the level of knowledge and the use of plant-derived preparations among people reporting to the Rehabilitation Clinic in Lublin

The use of plant-derived compounds in medicine arouses more and more interest. Most plants contain numerous active ingredients that may have therapeutic effects on the human body. For many years, herbs have been used as medicinal agents. However, it is necessary to learn about the chemical content of the plant as well as how they work on the human body.The aim of this study was to evaluate the use of preparations containing plant extracts and the assessment of respondents’ knowledge about plant resources with medicinal properties.The study group consisted of people who visited the Rehabilitation Department in Lublin. Respondents voluntarily filled out the questionnaire consisting of 21 questions. 33 persons were examined in total.More than 77% of those who participated in the study have ever applied preparations of plant origin. More than half rated their level of knowledge about medicinal plants as small. Respondents gained knowledge about data on herbs and herbal supplements from several sources. None of the respondents considers preparations containing plant extracts as fully safe for the body and no one would use it without consulting a doctor first. The majority of respondents (over 63%) rated the effectiveness of the plant-derived compounds as good. Over 90% of respondents noticed positive effects of the use of plant supplements. Most respondents did not use compounds of plant origin which might slow down the body’s aging process or improve memory and concentration. However, more than half of the respondents applied preparations containing sedative plant extracts.As seen in the studies and the discussion above, the prevalence of the use of plant-derived compounds among respondents is relatively large. Respondents do not have sufficient knowledge of these substances. Almost all respondents notice the positive impact of plant compounds on the body. There is a need for educational campaigns among society to enrich the knowledge on the use of herbal medicine and its side effects in details.

Isolation and identification of root-inhibiting compounds from corn gluten hydrolysate

Interest has centered on the use of plantderived compounds as natural herbicides, and they are considered to represent an environmentally sound approach to weed control. Corn gluten hydrolysate, found to have a growth-regulating effect on the root system of germinating grass seeds, has been suggested as a natural herbicide. A protocol was developed to extract, isolate, and identify the root-inhibiting compounds from corn gluten hydrolysate aqueous solution and a perennial ryegrass (Lolium perenne L.). A Petri dish bioassay was used to test the root-inhibiting activity. Five bioactive dipeptides were isolated by using Sephadex G-15 gel filtration, solid-phase extraction, and C18 reversed-phase high-performance liquid chromatography procedures. The five dipeptides were glutaminyl-glutamine, alaninyl-asparagine, alaninyl-glutamine, glycinyl-alanine, and alaninyl-alanine. Their root-inhibiting activity on perennial ryegrass was demonstrated in Petri dish bioassays.