Current Issues - Allelopathy Journal

This study aimed to predict the molecular docking study of inhibition of the most targeted genes of migraine headache by finding the effective or natural ligands derived from lavender (Lavandula angustifolia L.). Subsequently we did screening of several compounds having anti- inflammatory, antiseptic and anti-action using different in-silico approaches (Lipinski rule of five, made analysis and molecular docking tools). We found potent ligands against migraine headache and recommend that natural compounds of lavender are intense inhibitors against the migraine headache.

Rosemary oil (Rosmarinus officinalis L.) is a potential therapeutic agent to treat Alzheimer's disease (AD), characterized by cognitive decline and memory impairment. We reviewed the effects of rosemary oil on cognitive functions in individuals with Alzheimer's disease, foccusing on its bioactive compounds, particularly 1,8-cineole, which has neuroprotective and cognitive-enhancing properties. Preclinical studies have shown that rosemary oil improves memory and reduces cognitive deficits in animal models of Alzheimer's through acetylcholinesterase inhibition, antioxidant activity and modulation of neuroinflammation. Clinical studies further, showed that aromatherapy with rosemary oil enhances the cognitive function and sleep quality in elderly populations. This review aimed to synthesize current research on the efficacy of rosemary oil in managing Alzheimer's disease, its potential as a complementary therapy along with traditional pharmacological treatment. The findings showed that rosemary oil improves quality of life of Alzheimer's disease patients.

Flowers are rich sources of various medicinal active metabolites (Phenolics, alkaloids, terpenoids, essential oils etc), hence, they have strong antioxidant, anti-inflammatory and antibacterial properties. These could be used in pharmacognosy and health care products. Flowers are cultivated for ornamental and religious purposes, food, colour, dye, essential oil, cosmetics and pharmaceuticals. Flowers have great importance as temple offerings for worshipping the deities; which generates lot of floral waste, besides, floral waste also comes from floriculture as cut/ unsold flowers and floral refuge from industries which use flower as raw materials. This floral waste causes land, water and environmental pollution. This paper reviewed the current state of floral waste and its use in pharmacognosy and pharmacological applications.

This study aimed to explore Evernia prunastri, lichen potential as a source of bioactive flavonoids and natural precursors of vitamin D2. Extracts obtained by maceration and Soxhlet were subjected to phytochemical analysis, revealing a high content of total phenolics (25.5 mg GAE/100 g) and total flavonoids (0.285 mg QE/g). Antioxidant, anti-inflammatory and antibacterial activities were evaluated using in-vitro assays. Antioxidant potency, measured by DPPH assay, revealed IC₅₀ of 0.049 mg/mL, indicating notable activity. Inhibition of protein denaturation (indicator of anti-inflammatory activity), showed IC₅₀ of 388.52 μg/mL. The extracts also had moderate antibacterial activity against Escherichia coli and Pseudomonas aeruginosa. Finally, the detection of ergosterol a fungal sterol characteristic of lichens and a precursor of vitamin D₂ (ergocalciferol) by gas chromatography-mass spectrometry (GC/MS) confirmed the nutraceutical activity of this specie. This plant-based form of vitamin D is distinct from animal-derived vitamin D₃ (cholecalciferol), derived from 7-dehydrocholesterol. These results showed Evernia prunastri as a promising source of bioactive compounds with therapeutic and nutritional potential.

We evaluated the tolerance of 9- Zea mays L. varieties (Baby Corn, Bajaura sweet corn, Bajaura popcorn, Bajaura Makka, Girija composite, L-315, L-316, L-317 and L-318) against the maize weevil (Sitophilus zeamais Motsch). The experiment was done in ‘No-Choice Tests’ under the laboratory conditions in completely randomized design. The observations on the number of progeny emergence, grain damage (on number and weight basis) and weight loss were recorded. Preliminary observations revealed that the longest developmental period from egg to adult occurred in the Bajaura Popcorn variety, followed by Bajaura Sweet Corn. Resistance to the maize weevil varied significantly among the varieties, ranging from 88 % in Bajaura Sweet Corn and 86 % in Bajaura Popcorn to 24 % in Girjia Composite, indicating differential varietal responses to infestation. These variations may be due to differences in the genetic background of the cultivars. The identified tolerant genotypes could serve as valuable donors for breeding programmes to enhance resistance to maize weevil in new maize varieties.

This study investigated the allelopathic effects of phytochemical compounds in Averrhoa carambola L. [starfruit (family Oxalidaceae)] leaf leachates on seedling growth of Hordeum vulgare L. (Barley) and Eleucine coracana (L.) Gaertn. (Finger millet). The A. carambola leaf extract was bio-assayed to determine the bioactivities of compounds and their phytochemical nature. In GC-MS analysis, total 19 bioactive-chemical compounds were identified the major were: Triterpenes (21.31 %), Bis (2-ethylhexyl) phthalate (14.44 %), 3,7,11,15-Tetramethyl-2-hexadecen-1-ol (9.85 %), Gamma-Sitosterol (8.99 %) etc. Most of these suppressed the seedlings growth. In laboratory assay, effects of 3-concentrations (10 %, 20 % and 30 %) of leaf extract were determined on seed germination and seedling growth. To evaluate the allelopathic effects in nursery, 10 g, 20 g and 30 g leaf mulch was added per pot. Findings revealed dose-dependent dual allelopathic effects where low concentrations stimulated while higher concentrations acted as phytotoxic. It reduced seed germination, root length of Eleucine coracana and; shoot length and biomass of Hordeum vulgare. In pot culture, Eleucine coracana, compared to Hordeum vulgare showed more stimulation (hormesis) at lower concentrations and resistance at doses of mulch. This allelopathic tolerance in H. vulgare indicated its potential for inclusion of Averrhoa carambola in agroforestry systems. It is recommended to evaluate Averrhoa carambola for dose dependent allelopathic effects on the other important Himalayan crops under field conditions.

Amaranthus viridis L. and to determine the appropriate phenological stage of sorghum for extract collection. The experiment was done in greenhouse covered with transparent plastic, with 50 % shade to reduce solar radiation. Polyethylene containers were filled with 12 kg substrate (Soil, sand and manure in 3:1:0.5 ratio). The treatments were replicated thrice in completely randomized design. The sorghum extract was obtained at 3-phenological stages (E1, E3 and E6) and a control (witout extract) and 4-extract concentrations (0 %, 25 %, 50 % and 100 %). Using high-precision manual sprayer, 20 ml extract/plant was sprayed in 3-applications at 33,39 and 43 days after emergence (DAE) of A. viridis L., when the plants had enough leaves to receive the extract. The sorghum extract obtained at the phenological stages corresponding to the vegetative periods E1 and E3 greatly inhibited the growth of Amaranthus viridis L., thus, it was recommended to harvest sorghum leaves at these stages for extract preparation. The 25 %, 50 % and 100 % extract concentrations decreased the shoot and root growth of A. viridis L.. However, the highest growth inhibition occurred at the undiluted 100 % concentration, making it the most promising concentration for Amaranthus viridis L. control.

We determined the allelopathic effect of papyrus (Cyperus papyrus L) extracts (0,5,10 %) on growth and root nodules and their bacteria of two pea (Pisum sativum L) cultivars (Iraqi and Turkish, Local varieties). The extracts reduced the Plant height, root length, dry weight of shoot and root by 23.5 %, 42.30 %, 45.65 % and 50 %, respectively, in Iraqi variety. The aqueous extract of papyrus at the highest concentration of 10 % decreased the root nodules numbers in both varieties, the highest decrease (88.88 %) was in Iraqi variety. Morphological, biochemical and molecular analyses were performed on two bacterial strains isolated from the root nodules of the control sample and from the aqueous extract of papyrus leaves at 5 % concentration for the Iraqi variety, while no isolates were recorded at 10 % concentration. Sequence analysis using DNA BLAST showed 97 % similarity with bacterial isolates from the genus Siccibacter (strain Siccibacter colletis N16, accession number MN555377.1) and 99 % similarity with isolates from the genus Staphylococcus (strain Staphylococcus warneri Dk131, registered with NCBI). All isolates with 16S rRNA sequences were registered as new strains in Mosul in Gene Bank (NCBI) and the phylogenetic tree of these isolates was constructed using MEGA 6.

The limited availability of herbicides with new mechanisms of action is remarkable given the wide range of molecular targets in plants. Allelochemicals represent promising alternatives due to their structural diversity and broader chemical spectrum compared to conventional compounds. As an initial step in exploring new herbicide mechanisms, dose-response and IC50 assays are essential to determine effective concentrations. This petri dish bioassay study evaluated the allelochemical custonolide through dose-response curves and IC50 determination on Arabidopsis thaliana (L.) Heynh. Custonolide was tested at 50, 100, 200, and 300 μM in agar, assessing germination, shoot and root lengths, and fresh and dry masses. Data were analyzed by quadratic regression in R software (expdes.pt package), and IC50 values were calculated. Results revealed a clear dose-dependent inhibition of germination and growth. Germination decreased significantly at concentrations above 200 μM, while 50 and 100 μM caused a 49.89 % reduction compared to the control, with an IC50 of 104.08 μM. Shoot and root lengths showed reductions of 49.8 % and 51.21 %, with IC50 values of 104.08 μM and 112.07 μM, respectively. Biomass was especially sensitive, with IC50 values of 3.12 μM (fresh mass) and 1.67 μM (dry mass). These results demonstrated the potent herbicidal activity of custonolide, supporting its potential as a candidate for novel herbicide development.

We studied the effects of Eucalyptus leaves on the germination, growth and development of indigenous morning glory (Ipomeoa ssp.), corn (Zea Mays L.) and peanut (Arachis hypogea L.) in Lab. Bioassays and pot culture. Seeds were sown in pots soil mixed with Eucalyptus leaf material (Was the leaf material collected from Brazil or USA?) at 1 and 10 % (w/w) to assess effects on germination and seedlings weight. The pots were irrigated to fully moisten the paper with 1% and 10% leaf aqueous extracts to evaluate their effects on germination and seedlings growth. The allelochemicals in Eucalyptus leaves inhibited both the germination and growth of test crops, with indigenous plants showing the strongest inhibition. Phenols were detected in leaf extracts using the ferric chloride test and Folin-Ciocalteu method. Higher concentrations of Eucalyptus leaf extracts had higher amounts of phenols, which significantly reduced the seeds germination and growth. These findings suggested that Eucalyptus allelopathy hindered the crop establishment, posing ecological and economic challenges for Brazilian farmers.

We evaluated the anti-enterobacterial activity of C. zeylanicum bark essential oil against

4-pathogenic enteric bacterial strains [(Salmonella sp. (non-typhoidal), Shigella dysenteriae,

Escherichia coli (ATCC 25922) and Klebsiella pneumoniae (ATCC 700603)]. The essential oil

antibacterial activity was determined by the agar well-diffusion method. The inhibition zones were

measured to determine the extent of antibacterial efficacy. C. zeylanicum bark oil exhibited

significant inhibitory effects on all tested bacterial strains, suggesting its potential as a natural

therapeutic agent to treat gastrointestinal infections. Thus cinnamon bark oil may be used to develop

alternate treatment strategies, against drug-resistant enteric pathogens. Further investigations on the

chemical composition of oil and the mechanisms underlying its antibacterial action are essential to

support its potential applications in clinical therapeutics.

This study compared the antifungal efficacy of essential oils extracted from the bark of

Cinnamomum zeylanicum and Cinnamomum camphora. The antifungal activity of essential oils was

evaluated against 7-fungal strains (Aspergillus niger, Aspergillus flavus, Trichoderma viridae,

Fusarium oxysporum, Rhizopus stolonifer, Candida albicans and Penicillium chrysogenum) using agar

well diffusion, broth microdilution for Minimum Inhibitory Concentration (MIC) and time-kill kinetic

assays. C. zeylanicum bark oil was, dominated by cinnamaldehyde (72.4 %), exhibited superior and

broad-spectrum antifungal activity. It showed remarkable efficacy against C. albicans and

F. oxysporum, resulting in complete plate clearance and very low MIC values of 0.125 % and 0.25 %,

respectively. Time-kill assays confirmed its rapid fungicidal activity against C. albicans. In contrast,

C. camphora bark oil, rich in camphor (54.8 %), displayed high activity against P. chrysogenum

(MIC 0.5 %) but no inhibition of F. oxysporum. Statistical analysis revealed strong positive correlations

between the major constituents and the observed antifungal effects. There was significant potential of

C. zeylanicum bark oil as a natural antifungal agent for applications in medicine, agriculture and food

preservation. Further research is warranted to elucidate the precise mechanisms of action, conduct

in-vivo safety and efficacy studies and develop stable formulations for clinical and commercial use.

This study aimed to evaluate the antifungal efficacy of essential bark oil of Cinnamomum

zeylanicum against many pathogenic and non-pathogenic fungal strains. Essential oil was extracted

from the bark using the hydrodistillation method with a Clevenger apparatus and antifungal activity

was assessed by the plate diffusion technique. Results showed that C. zeylanicum essential bark oil

exhibited significant antifungal activity, suggesting its potential as a natural antifungal agent. These

findings indicated that the essential oil may serve as a promising candidate for broader applications,

warranting further evaluation of its efficacy and safety for human use.

This study aimed to evaluate the antimicrobial efficacy of essential leaf oils of Cinnamomum

zeylanicum and Cinnamomum tamala against a broad spectrum of bacterial strains (Vibrio cholerae,

Alcaligenes xylosoxidans, Staphylococcus aureus, Rhizobium trifolii, Klebsiella pneumoniae, Proteus

vulgaris, Shigella dysenteriae and Streptomyces cinerochromogenes). Essential oils antibacterial

activity was assessed by the agar diffusion method. The antimicrobial activity was determined based

on the Inhibition Zones Diameter. Results indicated that both C. zeylanicum and C. tamala leaf oils

had significant antibacterial potential, suggesting their promising role as natural antibacterial agents.

These findings warrant further investigation into their efficacy and safety for potential therapeutic

applications.

We studied the protective impacts of Thymus numidicus Poiret essential oil (TEO) on the

nephrotoxicity induced by TiO2 nanoparticles (NPs) at both histological and oxidative levels. Adult

male albino rats were randomly divided into four groups: Group-I: Control, Group-II: Received

12 mg/kg/day of TiO2 NPs, Group-III: Received 4μL/kg/day of Thymus numidicus Poiret essential

oil and Group-IV: Administered Essential oil and TiO2 NPs for 30 days. Administered TiO2 NPs

significantly increased the serum uric acid levels and creatinine levels than control. Furthermore,

rats exposed to TiO2 NPs increased MDA content with reduction in renal GSH, GPx and GST

activities when compared with control. Renal toxicities induced by TiO2 NPs were evident through

disturbances in oxidative-antioxidant system and changes in serum renal markers. However, these

changes were prevented and the antioxidant status was preserved when experimental rats were

treated with Thymus numidicus Poiret essential oil. The biochemical evidence of nephroprotection

was supported by the histological findings. This study demonstrated that Thymus numidicus Poiret

essential oil significantly decreased the adverse effects of TiO2 NPs, highlighting its role in

reducing nanoparticle-induced renal dysfunction. Its nephroprotective activity was attributed to its

chemical composition and antioxidant properties.

This study aimed to investigate the hypoglycaemic effects of Trianthema portulacastrum L.,

leaves and its in-vitro potential. The study involved DPPH radical scavenging and assay inhibition,

α-amylase and α-glucosidase to evaluate in-vitro anti-oxidant and antidiabetic properties. The dried

plant material was extracted with solvents of varying polarity (Petroleum ether, Ethyl acetate and

Ethanol) using Soxhlet’s apparatus, while aqueous extraction was done by decoction. Phytochemical

study revealed major chemical components in petroleum ether, ethyl acetate, ethanol and water

extracts. Ethyl acetate extract showed the presence of phenols and flavonoids, but lacked alkaloids.

Antioxidant action of extracts was evaluated using DPPH assay. For the ethyl acetate extract of

Trianthema portulacastrum leaves, the IC50 value was 147.65 µg/ml for DPPH respectively. Among

the extracts, ethyl acetate extract exhibited significant activity compared to petroleum ether, ethanol

and aqueous extracts. Inhibition of two major enzymes α-amylase and α-glucosidase, is the most

important treatment of Diabetes mellitus. Polysaccharides and saccharides are the major component

of the human diet and α-amylase and α-glucosidase are involved in their digestion. These saccharides

are first broken down into oligosaccharides by α-amylase and then α-glucosidase covert them into

simpler sugar molecules (monosaccharides). The inhibition of the digestive enzymes involved in

polysaccharide breakdown significantly reduces the blood sugar level. The anti-diabetic activity of T.

portulacastrum against α amylase and α glucosidase inhibition assay showed concentration

dependent inhibition (%). The ethyl acetate extract exhibited dose-dependent inhibitory effects on α-

amylase and α-glucosidase, likely due to flavonoids and/or phenolic compounds and their free radical

scavenging properties. The ethyl acetate extract of Trianthema portulacastrum showed promising

antidiabetic activity.

We isolated 30-bacterial isolates from tomato (Solanum lycopersicum L.) plant rhizosphere

roots and screened their ability to mitigate the pathogenic effects of Fusarium oxysporum fungus

on tomato plant. Initially 12-isolates among 30-were selected based on their antagonistic activity

against Fusarium and5-isolates exhibited strong Plant Growth-Promoting characteristics, were

further selected and identified using 16S rDNA analysis. The PGPR consortium was prepared

comprising all 5-selected isolates and was used in this study to analyse its positive effects on the

tomato plant against Fusarium infection. The PGPR consortium was applied in the roots15-days

before Fusarium inoculation and its effect was analysed for 3-days post-infection. PGPR-treated

plants significantly improved all measured parameters like total phenolics, total proteins and five

different PR proteins like peroxidise, β-1,3-Glucanase and chitinase, while the combined PGPR

and Fusarium treatment gave consistently higher yield. These findings suggested that PGPR pre-

treatments, enhanced the resistance against the Fusarium infection.

We did phytochemical screening of Nerium oleander L.,ethanolic and aqueous extracts, todetermine the content of total polyphenols and flavonoids, to test their in-vitro antioxidant activityby DPPH radical scavenging and antimicrobial activity using the disk diffusion method. The plantcontained flavonoids, gallic tannins, catechol tannins, saponins and terpenes. The total polyphenolsand flavonoids contents ranged from 65.321±4.93 mg GAE/g to 11.753±0.92 mg QE/g for theaqueous extract and 88.25±3.25 mg GAE/g to 10.035±0.34 mg QE/g for the ethanolic extract,respectively. N. oleander extracts had higher antioxidant activities (from 33.38±2.88 aqueous and10.97±1.66 μg/mL for ethanolic). The antimicrobial properties of N. oleander extracts wereevaluated against 3-Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa andSerratia marcescens), 2-Gram-positive bacteria (Staphylococcus epidermidis and Staphylococcusaureus) and 2-fungal species (Candida albicans and Candida parapsilosis). Both ethanolic andaqueous extracts demonstrated significant antimicrobial activity against all tested strains, except theSerratia marcescens. The ethanolic extract of N. oleander showed the highest antimicrobial activity,with inhibition zones of 15-17 mm against the most sensitive isolates. The lowest minimalinhibitory concentration (MIC) of 39 μg/mL was observed for the ethanolic extract against C.albicans, while the aqueous extract had an MIC of 78 μg/mL against P. aeruginosa.

This 15-days study evaluated the effects of drought stress (40 % field capacity) at the initial reproductive stage and increase of the allelopathic potential of Cosmos sulphureus Cav. Thereafter, fresh leaves were collected for malondialdehyde and proteomic tests and to prepare crude extract. Bioassays were done on crops [Lactuca sativa L., Sorghum bicolor (L.) Moench], Cucumis sativus L.] and weeds [Urochloa decumbens (Stapf) Webster, Portulaca oleracea L. and Panicum maximum Jacq.]. All extracts significantly inhibited the germination (5-90 %), depending on the species and extract concentration. However, the extracts from stressed plants were more inhibitory to germination (22.74 %), shoot growth (43.91 %) and root growth (35.60 %) than extracts from non-stressed plants (15.69 %, 44.70 % and 33.65 %, respectively). No significant differences were observed between the drought and non-stress conditions. It was concluded that drought stress (40 % field capacity) for 15-days, at the initial reproductive stage in Cosmos sulphureus Cav. plants, did not increase the allelopathic potential of this specie. These findings support further study of its bioherbicidal activity and sustainable weed control.