Microbial amelioration of salinity stress in endangered accessions of Iranian licorice (Glycyrrhiza glabra L.).

BACKGROUND: Glycyrrhiza glabra L. is a medicinal and industrial plant that has gone extinct due to different abiotic stress caused by climate change. To understand how the plant-associated microorganism can support this plant under salinity, we collected sixteen Iranian accessions of G. glabra L., inoculated their rhizomes with Azotobacter sp. (two levels, bacterial treatments, and no-bacterial treatments, and grown them under salinity stress (NaCl levels; 0, and 200 mM). RESULTS: Two accessions of Bardsir and Bajgah significantly showed higher resistant to salinity, for example by increasing crown diameter (11.05 and 11 cm, respectively) compared to an average diameter of 9.5 in other accessions. Azotobacter inoculation caused a significant increase in plant height and crown diameter. Among studied accessions, Kashmar (46.21%) and Ilam (44.95%) had the highest rate of membrane stability index (MSI). Evaluation of enzyme activity represented that bacterial application under salinity, increased polyphenol oxidase (PPO) (0.21 U mg-1 protein), peroxidase (POD) (3.09 U mg-1 protein U mg-1 protein), and phenylalanine ammonia-lyase (PAL) (17.85 U mg-1 protein) activity. Darab accession showed the highest increase (6.45%) in antioxidant potential compared with all studied accessions under Azotobacter inoculation. According to principal component analysis (PCA), it was found that the accession of Meshkinshahr showed a more remarkable ability to activate its enzymatic defense system under salt stress. Also, three accessions of Meshkinshahr, Eghlid, and Ilam were categorized in separated clusters than other accessions regarding various studied treatments. CONCLUSION: Analysis indicated that five accessions of Meshkinshahr, Rabt, Piranshahr, Bardsir, and Kermanshah from the perspective of induced systematic resistance are the accessions that showed a greater morphophysiological and biochemical outcome under salinity. This study suggested that, inoculation of with Azotobacter on selected accession can relieve salt stress and support industrial mass production under abiotic condition.

In Silico Evaluation of Iranian Medicinal Plant Phytoconstituents as Inhibitors against Main Protease and the Receptor-Binding Domain of SARS-CoV-2.

The novel coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which initially appeared in Wuhan, China, in December 2019. Elderly individuals and those with comorbid conditions may be more vulnerable to this disease. Consequently, several research laboratories continue to focus on developing drugs to treat this infection because this disease has developed into a global pandemic with an extremely limited number of specific treatments available. Natural herbal remedies have long been used to treat illnesses in a variety of cultures. Modern medicine has achieved success due to the effectiveness of traditional medicines, which are derived from medicinal plants. The objective of this study was to determine whether components of natural origin from Iranian medicinal plants have an antiviral effect that can prevent humans from this coronavirus infection using the most reliable molecular docking method; in our case, we focused on the main protease (Mpro) and a receptor-binding domain (RBD). The results of molecular docking showed that among 169 molecules of natural origin from common Iranian medicinal plants, 20 molecules (chelidimerine, rutin, fumariline, catechin gallate, adlumidine, astragalin, somniferine, etc.) can be proposed as inhibitors against this coronavirus based on the binding free energy and type of interactions between these molecules and the studied proteins. Moreover, a molecular dynamics simulation study revealed that the chelidimerine-Mpro and somniferine-RBD complexes were stable for up to 50 ns below 0.5 nm. Our results provide valuable insights into this mechanism, which sheds light on future structure-based designs of high-potency inhibitors for SARS-CoV-2.

Phytochemistry of Oliveria decumbens Vent. (Apiaceae) and its therapeutic potential: A systematic review.

Oliveria decumbens Vent., an annual herb resistant to harsh environmental conditions, is an aromatic medicinal plant of the Apiaceae family. O. decumbens has numerous pharmacological, food and feed, and cosmetic applications. This species is endemic to Iran, Iraq, and Turkey. Published literature, available until 30 November 2022 on the morphology, phytochemistry, and bioactivity of O. decumbens, has been reviewed, and appraised for the potential therapeutic potential of this species, utilizing the databases, Web of Science, Google Scholar, PubMed, and Dictionary of Natural Products. The search term used was O. decumbens. Some manuscripts were issued on the chemical components of O. decumbens essential oil (EO) and various extracts. The EO of O. decumbens was evaluated for its chemical composition and medicinal potential against various diseases. Thymol and carvacrol constituted the primary oxygenated monoterpenes detected in substantial amounts within the EO. Additionally, diverse metabolites of O. decumbens were examined for their bactericidal, antioxidant, larvicidal, and immunomodulatory effects. This review article discusses morphology, phenology, and geographical distribution of O. decumbens and presents a critical appraisal of its phytochemistry and therapeutic potential as documented in the published literature.

Photosynthesis and chlorophyll fluorescence of Iranian licorice (Glycyrrhiza glabra l.) accessions under salinity stress.

While salinity is increasingly becoming a prominent concern in arable farms around the globe, various treatments can be used for the mitigation of salt stress. Here, the effective presence of Azotobacter sp. inoculation (A1) and absence of inoculation (A0) was evaluated on Iranian licorice plants under NaCl stress (0 and 200 mM) (S0 and S1, respectively). In this regard, 16 Iranian licorice (Glycyrrhiza glabra L.) accessions were evaluated for the effects on photosynthesis and chlorophyll fluorescence. Leaf samples were measured for photosynthetic pigments (via a spectrophotometer), stomatal and trichome-related features (via SEM), along with several other morphological and biochemical features. The results revealed an increase in the amount of carotenoids that was caused by bacterial inoculation, which was 28.3% higher than the non-inoculated treatment. Maximum initial fluorescence intensity (F0) (86.7) was observed in the 'Bardsir' accession. Meanwhile, the highest variable fluorescence (Fv), maximal fluorescence intensity (Fm), and maximum quantum yield (Fv/Fm) (0.3, 0.4, and 0.8, respectively) were observed in the 'Eghlid' accession. Regarding anatomical observations of the leaf structure, salinity reduced stomatal density but increased trichome density. Under the effect of bacterial inoculation, salinity stress was mitigated. With the effect of bacterial inoculation under salinity stress, stomatal length and width increased, compared to the condition of no bacterial inoculation. Minimum malondialdehyde content was observed in 'Mahabad' accession (17.8 µmol/g FW). Principle component analysis (PCA) showed that 'Kashmar', 'Sepidan', 'Bajgah', 'Kermanshah', and 'Taft' accessions were categorized in the same group while being characterized by better performance in the aerial parts of plants. Taken together, the present results generally indicated that selecting the best genotypes, along with exogenous applications of Azotobacter, can improve the outcomes of licorice cultivation for industrial purposes under harsh environments.

Eco-friendly 'ochratoxin A' control in stored licorice roots - quality assurance perspective.

According to toxicity data, ochratoxin A (OTA) is the second most important mycotoxin and is produced by Aspergillus and Penicillium. As a natural antifungal agent, clove essential oil (CEO) is a substance generally recognised as safe (GRAS) and shows strong activity against fungal pathogens. Here, we aimed to investigate the control efficacy of CEO in nano-emulsions (CEN) against OTA production in licorice roots and rhizomes during storage. The experiments were performed under simulated conditions of all four seasons (i.e. Spring, Summer, Autumn and Winter). Relative humidity (RH) and temperature were simulated in desiccators along with various salt solutions in incubators. Fresh licorice roots were immersed in CEN at various concentrations (150, 300, 600, 1200 and 2400 µl/l). Before utilising the nano-emulsions, we measured their polydispersity index and mean droplet size by the dynamic light scattering (DLS) technique. Also, the chemical composition of the CEO was determined using GC and GC-MS analyses. Sampling was carried out to monitor OTA once every five days. The samples were dried immediately and analysed by high-performance liquid chromatography (HPLC). Results showed that various concentrations of CEN inhibited the growth of fungi and OTA production. The most effective CEN concentrations were 1200 and 2400 µl/l, which reduced OTA production to 19 and 20 ppb under Winter and Autumn conditions, respectively. These results suggest an effective eco-friendly method for the storage of licorice to reduce postharvest fungal decay.

Evaluation of metabolites in Iranian Licorice accessions under salinity stress and Azotobacter sp. inoculation.

Licorice (Glycyrrhiza glabra L.) is an industrial medicinal plant that is potentially threatened by extinction. In this study, the effects of salinity (0 and 200 mM sodium chloride (NaCl)) and Azotobacter inoculation were evaluated on 16 licorice accessions. The results showed that salinity significantly reduced the fresh and dry biomass (FW and DW, respectively) of roots, compared to plants of the control group (a decrease of 15.92% and 17.26%, respectively). As a result of bacterial inoculation, the total sugar content of roots increased by 21.56% when salinity was applied, but increased by 14.01% without salinity. Salinity stress increased the content of glycyrrhizic acid (GA), phenols, and flavonoids in licorice roots by 104.6%, 117.2%, and 56.3%, respectively. Integrated bacterial inoculation and salt stress significantly increased the GA content in the accessions. Bajgah and Sepidan accessions had the highest GA contents (96.26 and 83.17 mg/g DW, respectively), while Eghlid accession had the lowest (41.98 mg/g DW). With the bacterial application, the maximum amounts of glabridin were obtained in Kashmar and Kermanshah accessions (2.04 and 1.98 mg/g DW, respectively). Bajgah and Kashmar accessions had higher amounts of rutin in their aerial parts (6.11 and 9.48 mg/g DW, respectively) when their roots were uninoculated. In conclusion, these results can assist in selecting promising licorice accessions for cultivation in harsh environments.

Phytotoxic Potential and Phenolic Profile of Extracts from Scrophularia striata.

A large number of plants produce secondary metabolites known as allelochemicals that are capable of inhibiting the germination of competitive species. This process is known as allelopathy and is mediated by several classes of chemicals, among which phenolic compounds are the most frequent. Thus, plant allelochemicals can be used to control weeds in agricultural systems. In the present work, we analyzed the phenolic profile and phytotoxic potential of different extracts (pure water or water: ethanol 50:50) from Scrophularia striata plants that were collected from two ecological regions in Iran (Pahleh and Lizan). The total polyphenolic content (TPC), as evaluated by the Folin-Ciocolteau method, ranged from 28.3 mg/g in the aqueous extract obtained from the Lizan ecotype to 39.6 mg/g in the hydroalcoholic extract obtained from the Pahleh ecotype. Moreover, HPLC analysis was aimed at determining the content of eight phenolic compounds, namely eugenol, rosmarinic acid, hesperetin, hesperedin, trans-ferulic acid, vanillin, and caffeic acid. According to the results, rosmarinic acid appeared to be the most abundant component. The phytotoxic activities of S. striata extracts were examined on the seed germination of a crop species, Lepidium sativum, and two weeds, Chenopodium album and Malva sylvestris. All extracts showed inhibitory effects on these species. The efficiency of these inhibitory effects depended on the type of plant species, origin, and concentration of extract. The highest phytotoxic activity was caused by approximately 1% concentration of extract. The most susceptible weed was M. sylvestris. The extracts that were obtained from the Pahleh ecotype, notably the hydroalcoholic ones, showed higher phytotoxicity against L. sativum, C. album and M. sylvestris. These results encourage further studies to support the use of S. striata as a source of bioherbicides.