(R)-(-)-Aloesaponol III 8-Methyl Ether from Eremurus persicus: A Novel Compound against Leishmaniosis

Neurodegeneration: can metabolites from Eremurus persicus help?

The number of patients affected by neurodegenerative diseases is increasing worldwide, and no effective treatments have been developed yet. Although precision medicine could represent a powerful tool, it remains a challenge due to the high variability among patients. To identify molecules acting with innovative mechanisms of action, we performed a computational investigation using SAFAN technology, focusing specifically on HuD. This target belongs to the human embryonic lethal abnormal visual-like (ELAV) proteins and plays a key role in neuronal plasticity and differentiation. The results highlighted that the molecule able to bind the selected target was (R)-aloesaponol-III-8-methyl ether [(R)-ASME], a metabolite extracted from Eremurus persicus. Notably, this molecule is a TNF-α inhibitor, a cytokine involved in neuroinflammation. To obtain a suitable amount of (R)-ASME to confirm its activity on HuD, we optimized the extraction procedure. Together with ASME, another related metabolite, germichrysone, was isolated. Both ASME and germichrysone underwent biological investigation, but only ASME confirmed its ability to bind HuD. Given the multifactorial nature of neurodegenerative diseases, we decided to investigate ASME as a proteasome activator, being molecules endowed with this kind of activity potentially able to counteract aggregations of dysregulated proteins. ASME was able to activate the considered target both in enzymatic and cellular assays. Therefore, ASME may be considered a promising hit in the fight against neurodegenerative diseases.

Structural Insights into the Ligand–LsrK Kinase Binding Mode: A Step Forward in the Discovery of Novel Antimicrobial Agents

LsrK is a bacterial kinase that triggers the quorum sensing, and it represents a druggable target for the identification of new agents for fighting antimicrobial resistance. Herein, we exploited tryptophan fluorescence spectroscopy (TFS) as a suitable technique for the identification of potential LsrK ligands from an in-house library of chemicals comprising synthetic compounds as well as secondary metabolites. Three secondary metabolites (Hib-ester, Hib-carbaldehyde and (R)-ASME) showed effective binding to LsrK, with KD values in the sub-micromolar range. The conformational changes were confirmed via circular dichroism and molecular docking results further validated the findings and displayed the specific mode of interaction. The activity of the identified compounds on the biofilm formation by some Staphylococcus spp. was investigated. Hib-carbaldehyde and (R)-ASME were able to reduce the production of biofilm, with (R)-ASME resulting in the most effective compound with an EC50 of 14 mg/well. The successful application of TFS highlights its usefulness in searching for promising LsrK inhibitor candidates with inhibitor efficacy against biofilm formation.

Evaluation of antioxidant and anti-ulcerogenic effects of Eremurus persicus (Jaub & Spach) Boiss leaf hydroalcoholic extract on ethanol-induced gastric ulcer in rats

This study aimed to investigate the antioxidant and protective effect of E. persicus leaf hydroalcoholic extract (EPE) in preventing gastric ulcers induced by ethanol in rats. Wistar rats weighing 180-220 g were randomly divided into five groups. These groups included negative control (normal) group, positive control (ethanolic) group, comparative control (ranitidine recipient) group, group recipient the dose of 250 mg/kg plant extract, and group recipient the dose of 500 mg/kg plant extract. One hour after gavage of the drug and extract, the gastric ulcer was induced by feeding 1 ml of 96% ethanol to each animal except the rats of the negative control group. After one hour, the rats were killed, and their stomachs were separated. Then, the gastric Ulcer index (UI), pH, oxidative stress parameters, and histopathological changes in the stomach of all groups were measured. Pre-treatment of ethanol-induced rats with the EPE reduced (P < 0.05) the ulcer index and gastric juice pH, compared to ethanolic group rats. Furthermore, pre-treatment with EPE at a dose-dependent manner, alleviated the gastric oxidative stress injury in rats through increase the activity of CAT, tissue NO^· and GSH levels. EPE also was able to decrease the levels of ROS, MDA, PCO and serum NO^·. According to the results, it can be concluded that pre-treatment with EPE prevents the formation of gastric ulcers caused by ethanol, which can be attributed to the antioxidant activity of plant polyphenols compounds.

Green Approach: ''A Forwarding Step for Curing Leishmaniasis-A Neglected Tropical Disease''

The present review focuses on a dreaded vector-mediated leishmaniasis, with the existing therapeutic approaches including a variety of drugs along with their limitations, the treatment with natural compounds, and different types of metal/metal oxide nanoparticles (NPs). As evidenced, various metallic NPs, comprising silver, silver oxide, gold, zinc oxide, titanium, lead oxide, etc., played a curative role to treat leishmaniasis, are also presented. Keeping in view the advance success of vaccines against the prevalent dreaded diseases in the past and the present scenario, efforts are also being made to develop vaccines based on these NP formulations.

Iranian plant Eremurus persicus: an overview of botany, traditional uses, phytochemistry and pharmacology

Eremurus persicus (Jaub. & Spach) Boiss. commonly known as "Serish" is a valuable ornamental plant with culinary uses and also utilized in traditional medicine for treating Gastrointestinal diseases. This comprehensive study was performed to investigate the pharmacological and biological effects of E. persicus and the compounds identified and isolated from it in order to encourage researchers to study it further. Despite the few number of studies on the ethnopharmacology of the plant E. persicus, however studies conducted on either crude extracts, solvent fractions or isolated pure compounds from E. persicus a varied range of biological effects comprising antibacterial, anti-fungal, anti-diabetic and etc. have reported. Phytochemical analysis of different parts of E. persicus unveiled 52 phytochemicals. However, the toxicity of this plant and its ethnopharmacological claims should be thoroughly investigated.

Vibrational Circular Dichroism Absolute Configuration of Natural Products From 2015 to 2019

Although demonstrated in 1975, vibrational circular dichroism (VCD) finally started to popularize during this century as a reliable tool to determine the absolute configuration (AC) of organic molecules. This research field continues to be a very dynamic one, in particular for the study of natural products which are a unlimited source of chiral molecules. It therefore turns of interest to summarize the accomplishments published in recent years and to comment on some eventual difficulties that emerged in rare cases to complete the AC determination task. Therefore the aim of this review is to update VCD results for the AC assignment of natural products published from 2015 to 2019, a period in which VCD was reported in some 126 publications involving almost 300 molecules. They are organized according the type of studied metabolite allowing an easily search. The molecules correspond to 28 monoterpenes concerning 17 papers, to 42 sesquiterpenes in 14 papers, to 51 diterpenes in 19 publications, to 5 other terpenoids in three papers, to 48 aromatic molecules in 15 reports, to 20 polyketides in 10 publications, to 27 miscellaneous formulas also in 10 papers, and to 76 nitrogen containing compounds, which include alkaloids and their synthetic analogs, in 38 articles. The landscape of reviewed molecules is quite wide as it goes from simple monoterpenes, like borneol or camphor, to very relevant biological molecules like the alkaloid cocaine or tadalafil samples to distinguish genuine and counterfeit Cialis®. In addition, 5 natural products and a simple derivative published outside the reviewed period, were used to illustrate some aspects of density functional theory calculations.

Isolation of secondary metabolites from the Iranian medicinal plant Eremurus persicus

Eremurus persicus (Jaub. & Spach) Boiss. belonging to Xanthorrhoeaceae family is an endemic medicinal plant widely distributed in Iran. Its leaves have been traditionally used as a food and also as medicinal plant. Regarding the widespread application of E. persicus in Iranian folk medicine, and the insignificant investigation of its components, this study aimed at the isolation and identification of major secondary metabolites of this plant. By applying various chromatographic techniques, corchoionoside A (1), 4-amino-4-carboxychroman-2-one (2), isoorientin (3), ziganein 5-methyl ether (4), auraptene (5), and imperatorin (6) were isolated from the EtOAc and CHCl₃ fractions of the crude extract. Except isoorientin (3), all the identified phytoconstituents were reported for the first time from Eremurus genus.

Microwave-Assisted Extraction and HPLC-UV-CD Determination of (S)-usnic Acid in Cladonia foliacea

During the years, many usnic acid (UA) conjugates have been synthesized to obtain potent endowed with biological properties. Since (S)-UA is less abundant in nature than (R)-enantiomer, it is difficult to source, thus precluding a deeper investigation. Among the lichens producing UA, Cladonia foliacea is a valuable (S)-UA source. In the present work, we report on a rapid HPLC-UV/PAD-CD protocol suitable for the analysis and the identification of the main secondary metabolites present in C. foliacea extract. Best results were achieved using XBridge Phenyl column and acetonitrile and water, which were both added with formic acid as mobile phase in gradient elution. By combining analytical, spectroscopical, and chiroptical analysis, the most abundant analyte was unambiguously identified as (S)-UA. Accordingly, a versatile microwave-assisted extractive (MAE) protocol, assisted by a design of experiment (DoE), to quantitatively recover (S)-UA was set up. The best result in terms of UA extraction yield was obtained using ethanol and heating at 80 °C under microwave irradiation for 5 min. Starting from 100 g of dried C. foliacea, 420 mg of (S)-UA were achieved. Thus, our extraction method resulted in a suitable protocol to produce (S)-UA from C. foliacea for biological and pharmaceutical investigation or commercial purposes.

Intra- and interspecific diversity analyses in the genus Eremurus in Iran using genotyping-by-sequencing reveal geographic population structure

Eremurus species, better known as 'Foxtail Lily' or 'Desert Candle', are important worldwide in landscaping and the cut-flower industry. One of the centers of highest diversity of the genus Eremurus is Iran, which has seven species. However, little is known about the genetic diversity within the genus Eremurus. With the advent of genotyping-by-sequencing (GBS), it is possible to develop and employ single nucleotide polymorphism (SNP) markers in a cost-efficient manner in any species, regardless of its ploidy level, genome size or availability of a reference genome. Population structure and phylogeographic analyses of the genus Eremurus in Iran using a minimum of 3002 SNP markers identified either at the genus level or at the species level from GBS data showed longitudinal geographic structuring at the country scale for the genus and for the species E. spectabilis and E. luteus, and at the regional scale for E. olgae. Our analyses furthermore showed a close genetic relatedness between E. olgae and E. stenophyllus to the extent that they should be considered subspecies within an E. olgae/stenophyllus species complex. Their close genetic relatedness may explain why crosses between these two (sub)species have been found in the wild and are exploited extensively as ornamentals. Last, current species identification, while robust, relies on flower morphology. A subset of seven SNPs with species-specific (private) alleles were selected that differentiate the seven Eremurus species. The markers will be especially useful for cultivar protection and in hybrid production, where true hybrids could be identified at the seedling stage.

Vibrational optical activity for structural characterization of natural products

This review presents the recent progress towards elucidating the structures of chiral natural products and applications using vibrational optical activity (VOA) spectroscopy.

Secondary metabolites profile and physiological leaf traits in wild and cultivated Corylus avellana under different nutritional status

Leaf secondary metabolites production and physiological leaf traits were analyzed in Corylus avellana wild type (WT) and cultivar (cv. 'Tonda Gentile Trilobata', TGT) under different nutrient supplies. Three treatments were applied: control treatment with no fertilizer supply (WT_C and TGT_C), low nutrient treatment (WT_LN and TGT_LN) and high nutrient treatment (WT_HN and TGT_HN). The analysis of leaf extracts showed a higher concentration of Quercitrin and Myricitrin, with the highest concentrations of both the compounds in WT than TGT. This result can be related to the ecological role of flavonoids, including also antimicrobial properties, which resulted more useful in the understory forest form which hazelnut wild type originates. Therefore, their lower concentration in TGT can be relate to the genetic background of TGT cultivar with a lesser intrinsic need to produce such compounds and justified by a usual growth under more controlled environmental conditions, including also pest and disease control.

Anti-Multiple Myeloma Potential of Secondary Metabolites from Hibiscus sabdariffa

Multiple myeloma (MM) belongs to hematological cancers and its incidence is increasing worldwide. Despite recent advances in its therapy, MM still causes many deaths every year. In fact, current therapies sometimes fail and are associated with severe adverse effects, including neurotoxicity. As a part of our ongoing efforts to discover new potential therapies against MM, we prepared Hibiscus sabdariffa extracts obtained by a microwave-assisted solvent extraction and investigate their activity by in vitro assays on the RPMI-8226 cell line. The bioguided fractionation of the crude ethanolic extract allowed the identification of HsFC as the most effective extract. We assessed cell viability (MTT and Tripan blue test), cell migration (Boyden chamber assay), and neurotoxicity (DRG neurotoxicity assay). The promising results prompted us to further fractionate HsFC and we obtained two molecules effective against RPMI-8226 cells without neurotoxic effects at their active concentrations. Moreover, both compounds are able to significantly reduce cell migration.

The use of a microwave-assisted solvent extraction coupled with HPLC-UV/PAD to assess the quality of Marrubium vulgare L. (white horehound) herbal raw material

INTRODUCTION

Marrubium vulgare is a herbal remedy presents in several European Pharmacopoeias and commonly marketed as white horehound. The chemotaxonomic marker of Marrubium genus is marrubiin and its content may change in response to biotic and abiotic stress.

OBJECTIVE

Development of a microwave-assisted solvent extraction (MASE) methodology suitable for exhaustively extracting marrubiin from M. vulgare leaves, easily applicable to large sets of samples. Evaluation of the influence of copper(II) on marrubiin production.

MATERIAL AND METHODS

M. vulgare leaves were dried, extracted exploiting MASE and analysed via high-performance liquid chromatography ultraviolet photodiode array detection (HPLC-UV/PAD) system. A design of experiments approach was adopted to select the best extraction conditions. Extraction parameters (solvent composition, extraction time and temperature), were studied applying two full factorial experimental designs in a sequential approach. To analyse samples, a rapid HPLC-UV/PAD method was set up.

RESULTS

The best results in terms of marrubiin extraction yield were obtained extracting samples at 120°C with 100% ethanol, for 15 min (3 × 5 min microwave cycles). The developed methodology was successfully applied to matrices grown in Greenhouse conditions and under stress induced by copper(II), selected as model agent for abiotic stress. Progressively decreasing production of marrubiin was evidenced in connection with treatment with 80, 200 and 300 mg/L copper sulphate.

CONCLUSION

An efficient methodology for the extraction and determination of the amount of marrubiin in large sets of samples of M. vulgare plants was developed. Results demonstrated that marrubiin is an easily detectable marker useful for evaluating M. vulgare reaction to stress.

Phytotoxic Activity of Metabolites Isolated from Rutstroemia sp.n., the Causal Agent of Bleach Blonde Syndrome on Cheatgrass (Bromus tectorum)

A fungal pathogen soon to be described as Rutstroemia capillus-albis (Rutstroemiaceae, Helotiales, Leotiomycetes) has been identified as the causal agent of 'bleach blonde syndrome' on the invasive annual grass weed Bromus tectorum (cheatgrass) in western North America. This apparently common but previously undescribed disease causes premature senescence and sterility, but does not affect seed germination or seedling emergence and growth. This study investigated whether the new species produces phytotoxins that could be implicated in pathogenesis. The compounds 9-O-methylfusarubin, 9-O-methylbostrycoidin, 5-O-methylnectriafurone, trans-methyl-p-coumarate and terpestacin were isolated from the solid culture of this fungus. The undescribed absolute stereochemistry at C-3 of 9-O-methylfusarubin and at C-1' of 5-O-methylnectriafurone were assigned by applying electronic and vibrational circular dichroism (ECD and VCD) combined with computational methods and the advanced Mosher's method, respectively. The first three listed compounds are naphtoquinone pigments, while terpestacin is a sesterterpene, and trans-methyl-p-coumarate could be the product of an unusual fungal phenylpropanoid biosynthesis pathway. In a juvenile plant immersion bioassay, both 9-O-methylfusarubin and terpestacin proved to be highly toxic at 10^-4 M, causing wilting and plant death within 10 days. This finding suggests that these two compounds could play a role in pathogenesis on B. tectorum.

Regulation of Aquaporin Functional Properties Mediated by the Antioxidant Effects of Natural Compounds

Some aquaporins (AQPs) have been recently demonstrated to facilitate the diffusion of hydrogen peroxide (H₂O₂) from the producing cells to the extracellular fluid, and their reactive oxygen species scavenging properties have been defined. Nevertheless, the identification of different AQPs acting as peroxiporins, their functional role in eustress and distress, and the identification of antioxidant compounds able to regulate AQP gating, remain unsolved. This study aims to investigate, in HeLa cells: (1) the expression of different AQPs; (2) the evaluation of naringenin, quercetin, (R)-aloesaponol III 8-methyl ether, marrubiin, and curcumin antioxidant profiles, via α,α-diphenyl-β-picrylhydrazyl assay; (3) the effect of the compounds on the water permeability in the presence and in the absence of oxidative stress; and (4) the effect of pre- and post-treatment with the compounds on the H₂O₂ content in heat-stressed cells. Results showed that HeLa cells expressed AQP1, 3, 8, and 11 proteins. The oxidative stress reduced the water transport, and both pre- and post-treatment with the natural compounds recovering the water permeability, with the exception of curcumin. Moreover, the pre- and post-treatment with all the compounds reduced the H₂O₂ content of heat-stressed cells. This study confirms that oxidative stress reduced water AQP-mediated permeability, reversed by some chemical antioxidant compounds. Moreover, curcumin was shown to regulate AQP gating. This suggests a novel mechanism to regulate cell signaling and survival during stress, and to manipulate key signaling pathways in cancer and degenerative diseases.

Marrubium vulgare L. Leave Extract: Phytochemical Composition, Antioxidant and Wound Healing Properties

Several factors contribute in wound generation, e.g., accidental traumas or surgery, and in certain cases, this dermal injury may have a devastating outcome. When skin damage occurs, the human body puts in place a sophisticated choreography, which involves numerous repairing processes to restore physiological conditions. Nevertheless, natural healing mechanisms are ineffective towards chronic or non-healing wounds and thus, therapeutic strategies may represent the only beneficial alternative to counteract these tissue insults. Over the years, numerous studies showed the great potential of plants in promoting wound healing, by virtue of their high contents in antioxidant species. These compounds trigger a molecular cascade that collimate into the promotion of reparative processes. In this article, we report on the potential effect on wound healing of Marrubium vulgare L., a medicinal plant well known for several pharmaceutical activities. To this aim, the methanolic extract was prepared and subjected to a phytochemical investigation, quantifying the amount of marrubiin via NMR and drawing the phytochemical fingerprint via high performance liquid chromatography-ultra violet/photodiode-array detection-electrospray/mass (HPLC-UV/PAD-ESI/MS) analysis. Lastly, the antioxidant properties and wound healing potential have been evaluated.