1,5-dihydroxyanthraquinones and an anthrone from roots of Rumex crispus

Two new anthraquinone derivatives from Saprosma crassipes H. S. Lo

Two new anthraquinone derivatives sapranquinones A and B (1 and 2) together with two known biogenetically related anthraquinone derivatives (3 and 4) were isolated from the stems of Saprosma crassipes H. S. Lo. The structures of these compounds were elucidated using comprehensive spectroscopic methods. Compounds 1-4 were evaluated for their antibacterial activities and compounds 1 and 3 had a broad spectrum antibacterial activity against Staphylococcus albus, Escherichia coli, Bacillus cereus, Micrococcus tetragenus, and Micrococcus luteus with MIC values ranging from 1.25 to 5 μg/mL.

More Than Just a Weed: An Exploration of the Antimicrobial Activity of Rumex crispus using a Multivariate Data Analysis Approach

Plants have a long history of use for their medicinal properties. The complexity of botanical extracts presents unique challenges and necessitates the application of innovative approaches to correctly identify and quantify bioactive compounds. For this study, we used untargeted metabolomics to explore the antimicrobial activity of Rumex crispus (yellow dock), a member of the Polygonaceae family used as an herbal remedy for bacterial infections. Ultra-performance liquid chromatography coupled with high resolution mass-spectrometry (UPLC-MS) was used to identify and quantify the known antimicrobial compound emodin. In addition, we used biochemometric approaches to integrate data measuring antimicrobial activity from R. crispus root starting material and fractions against methicillin-resistant Staphylococcus aureus (MRSA) with UPLC-MS data. Our results support the hypothesis that multiple constituents, including the anthraquinone emodin, contribute to the antimicrobial activity of R. crispus against MRSA.

The genus Rumex (Polygonaceae): an ethnobotanical, phytochemical and pharmacological review

Rumex L., a genus in Polygonaceae family with about 200 species, is growing widely around the world. Some Rumex species, called "sorrel" or "dock", have been used as food application and treatment of skin diseases and hemostasis after trauma by the local people of its growing areas for centuries. To date, 29 Rumex species have been studied to contain about 268 substances, including anthraquinones, flavonoids, naphthalenes, stilbenes, diterpene alkaloids, terpenes, lignans, and tannins. Crude extract of Rumex spp. and the pure isolates displayed various bioactivities, such as antibacterial, anti-inflammatory, antitumor, antioxidant, cardiovascular protection and antiaging activities. Rumex species have important potential to become a clinical medicinal source in future. This review covers research articles from 1900 to 2022, fetched from SciFinder, Web of Science, ResearchGate, CNKI and Google Scholar, using "Rumex" as a search term ("all fields") with no specific time frame set for the search. Thirty-five Rumex species were selected and summarized on their geographical distribution, edible parts, traditional uses, chemical research and pharmacological properties.

Phytotherapy for Wound Healing: The Most Important Herbal Plants in Wound Healing Based on Iranian Ethnobotanical Documents

Wound healing is a process that starts with the inflammatory response after the occurrence of any damage. This process initiates by restoring the wound surface coating tissue, migrating fibroblasts to form the required collagen, forming a healing tissue and finally, leading to contortion and extraction of the wound. Today, various drugs are used to heal wounds. However, the drugs used to repair wounds have some defects and side effects. In spite of all attempts to accelerate wound healing definitely, no safe drug has been introduced for this purpose. Therefore, the necessity to identify herbal plants in ethnopharmacology and ethnobotany documents with healing effects is essential. In this article, we tried to review and present effective Iranian medicinal plants and herbal compounds used for wound healing. Searching was performed on databases, including ISI Web of Science, PubMed, PubMed Central, Scopus, ISC, SID, Magiran and some other databases. The keywords used included wound healing, skin treatment, medicinal plants, ethnobotany, and phytotherapy. In this regard, 139 medicinal plants effective on wound healing were identified based on ethnopharmacology and ethnobotanical sources of Iran. Plants such as Salvia officinalis, Echium amoenum, Verbascum spp., G1ycyrrhiza glabra, Medicago sativa, Mentha pulegium, Datura stramonium L., Alhagi spp., Aloe vera, Hypericum perforatum, Pistacia atlantica and Prosopis cineraria are the most important and useful medicinal plants used for wound healing in Iran. These native Iranian medicinal plants are rich in antioxidants and biological compounds and might be used for wound healing and preparation of new drugs.

The photoactivity of natural products - An overlooked potential of phytomedicines?

BACKGROUND

Photoactivity, though known for centuries, is only recently shifting back into focus as a treatment option against cancer and microbial infections. The external factor light is the ingenious key-component of this therapy: Since light activates the drug locally, a high level of selectivity is reached and side effects are avoided. The first reported photoactive medicines were plant extracts. Synthetic entities (so-called photosensitizers PSs), however, paved the route towards the clinical approval of the so-called photodynamic therapy (PDT), and thus natural PSs took a backseat in the past.

HYPOTHESIS

Many isolated bioactive phytochemicals hold a hidden photoactive potential, which is overlooked due to the reduced common awareness of photoactivity.

METHODS

A systematic review of reported natural PSs and their supposed medicinal application was conducted by employing PubMed, Scifinder, and Web of Science. The identified photoactive natural products were compiled including information about their natural sources, their photoyield, and their pharmacological application. Furthermore, the common chemical scaffolds of natural PS are shown to enable the reader to recognize potentially overlooked natural PSs.

RESULTS

The literature review revealed over 100 natural PS, excluding porphyrins. The PSs were classified according to their scaffold. Thereby it was shown that some PS-scaffolds were analyzed in a detailed way, while other classes were only scarcely investigated, which leaves space for future discoveries. In addition, the literature revealed that many PSs are phytoalexins, thus the selection of the starting material significantly matters in order to find new PSs.

CONCLUSION

Photoactive principles are ubiquitous and can be found in various plant extracts. With the increasing availability of light-irradiation setups for the identification of photoactive natural products, we anticipate the discovery of many new natural PSs in the near future. With the accumulation of chemically diverse PSs, PDT itself might finally reach its clinical breakthrough as a promising alternative treatment against multi-resistant microbes and cancer types.

Comparison of the Proximate Composition, Vitamins (Ascorbic Acid, α-Tocopherol and Retinol), Anti-Nutrients (Phytate and Oxalate) and the GC-MS Analysis of the Essential Oil of the Root and Leaf of Rumex crispus L

Medicinal plants are a pertinent and effective remedy, employed in indigenous healthcare systems by traditional healers. This study focused on proximate parameters, minerals, vitamins, anti-nutrients and essential oil of the root and leaf of the medicinal plant; R. crispus, using the standard food analysis techniques. The result reveals that the moisture content of the leaf (7.57 ± 0.40%) and root (7.59 ± 0.08%) was not significantly different. The leaf has a higher ash, crude fat, fibre and mineral content than the root, except the carbohydrate (57.74 ± 3.06%) and Ca (1190.0 ± 0 mg/100g) values which are quite higher in the root. Traces of phytate was found in the leaf (1.15 ± 0.74%) and root (1.38 ± 0.27%) of R. crispus. The highest value of retinol, ascorbic acid and α-tocopherol was found in dried leaf (1.29 ± 0.014 mg retinol/100g), fresh leaf (159.73 ± 26.77 mg ascorbic acid/100g) and fresh root (54.90 ± 0.39 mg α-tocopherol/100g) respectively. The principal compound in the essential oil of the leaf are; 5-Eicosene, (E)-, docos-1-ene, trans-5-Octadecene, tetradecane while those found in the root are; 1-Heptacosanol, 4-Methyloctane, ethylcyclohexane, eucalyptol, m-Xylene, octadecane, phytol, and tetradecane. The research reveals that R. crispus may not only be used for medicinal purposes but could also be suitable for a complementary diet.

The Genus Rumex: Review of traditional uses, phytochemistry and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

The approximately 200 species of the genus Rumex (sorrel, Polygonaceae) are distributed worldwide (European, Asian, African and American countries). Some species have been used traditionally as vegetables and for their medicinal properties. Based on the traditional knowledge, different phytochemical and pharmacological activities have been at the focus of research. This review aims to provide an overview of the current state of knowledge of local and traditional medical uses, chemical constituents, pharmacological activities, toxicity, and safety of Rumex species, in order to identify the therapeutic potential of Rumex species and further directions of research.

MATERIALS AND METHODS

The selection of relevant data was made through a search using the keyword "Rumex" in "Scopus", "Google Scholar", "Web of Science", "PubMed", and "ScienceDirect" databases. Plant taxonomy was validated by the databases "The Plant List", and "Mansfeld's Encyclopedia". Additional information on traditional use and botany was obtained from published books and MSc dissertations.

RESULTS

This review discusses the current knowledge of the chemistry, the in vitro and in vivo pharmacological studies carried out on the extracts, and the main active constituents, isolated from plants of genus Rumex. Although, there are about 200 species in this genus, most of the phytochemical and pharmacological studies were performed on up to 50 species. The aerial parts, leaves and roots of the plants are used as vegetables and for the treatment of several health disorders such as mild diabetes, constipation, infections, diarrhoea, oedema, jaundice, and as an antihypertensive, diuretic and analgesic and in case of skin, liver and gallbladder disorders, and inflammation. Many phytochemical investigations on this genus confirmed that Rumex species are rich in anthraquinones, naphthalenes, flavonoids, stilbenoids, triterpenes, carotenoids, and phenolic acids. Moreover, it draws the attention that high level of oxalic acid in some species can cause toxicity (kidney stones) if consumed large quantity.

CONCLUSIONS

This review confirms that some Rumex species have emerged as a good source of the traditional medicine for treatment of inflammation, cancer and different bacterial infections and provides new insights for further promising investigations on isolated compounds, especially quercetin 3-O-glucoside, emodin, nepodin, torachrysone, and trans-resveratrol to find novel therapeutics and aid drug discovery. In addition, hepatoprotective, antiviral and antidiabetic activities should have priority in future pharmacological studies. However, for applying species to prevent or treat various diseases, additional pharmacological studies are needed to find the mechanism of actions, safety and efficacy of them before starting clinical trials.

Identification of a new naphthalene and its derivatives from the bulb of eleutherine americana with inhibitory activity on lipopolysaccharide-induced nitric oxide production

A new naphthoquinone, (-)-3-[2-(acetyloxy)propyl]-2-hydroxy-8-methoxy-1,4-naphthoquinone (1) was isolated from the bulb of Eleutherine americana MERR. et HEYNE (Iridaceae) together with two known compounds, eleutherinol (6) and 1,5-dihydroxy-3-methylanthraquinone (7) which were found in this species for the first time. The other known compounds, (-)-isoeleutherin (2), (+)-eleutherin (3), (-)-hongconin (4), and (+)-dihydroeleutherinol (5) which were reported previously from this species, were also isolated in the present study. Compounds 2-6 exhibited potent inhibitory activity on nitric oxide production in RAW 264.7 lipopolysaccharide-activated mouse macrophage cells with IC(50) values of 7.7, 11.4, 19.8, 21.7, and 34.4 microM, respectively, whereas the other two compounds, 1 and 7, were inactive. The structure of compound 1 was elucidated by spectroscopic data analysis including 1D and 2D NMR experiments.

Ab initio tools for the accurate prediction of the visible spectra of anthraquinones

The UV/vis absorption spectra of 101 anthraquinones solvated in two protic solvents (methanol and ethanol) has been theoretically predicted using the time-dependent density functional theory (TD-DFT) for the excited state calculations and the polarizable continuum model (PCM) for evaluating bulk solvent effects. Two functionals (B3LYP and PBE0) have been used and they provide similar mean absolute deviations (approximately 0.09 eV) but mean signed errors presenting opposite signs. The errors can be minimized by using simple or multiple linear regression, the latter combining the results of both functionals to reach an optimal estimation of the lambda(max) (mean absolute error 0.06 eV). Specific fittings for the two media have been performed and it turned out that our approach is even more efficient for anthraquinones solvated in ethanol.

Antioxidant activity and inhibition of alpha-glucosidase by trans-resveratrol, piceid, and a novel trans-stilbene from the roots of Israeli Rumex bucephalophorus L

The roots of Rumex bucephalophorus, collected in Israel, were analyzed for trans-stilbenes. Two stilbene-O-glycosyl derivatives were identified, in addition to 3,5,4'-trihydroxystilbene (1) (resveratrol). The stilbene-O-glycosyl derivatives were 5,4'-dihydroxystilbene-3-O-beta-d-glucopyranoside (2) (piceid) and the new 5,4'-dihydroxystilbene-3-O-alpha-arabinopyranoside (3), which is being named rumexoid. The structure of rumexoid was elucidated by using spectroscopic data. The antioxidant capacities of stilbenoids 1-3 were determined and expressed as trolox equivalent antioxidant capacity (TEAC). TEAC value for trans-resveratrol was highest (2.7) and for rumexoid lowest (1.5). In vitro, trans-resveratrol and rumexoid demonstrated a potent inhibitory effect on alpha-glucosidase activity (IC50 < 0.1 and < 0.5 mM, respectively). The commercial antidiabetic agent acarbose was shown to inhibit only 35% of the enzyme activity at 0.5 mM. The addition of piceid to the reaction mixture did not inhibit alpha-glucosidase in vitro in the range of concentrations used. These findings extend the range of reported beneficial effects of stilbene derivatives, and demonstrate the multifaceted activities that dietary polyphenols may exert in the intestine, where their concentrations are highest in the body.

The chemical investigations on the ripe fruits of Ammi visnaga (Lam.) Lamarck growing in Turkey

Two furanochromones and one furanochromone glycoside were isolated from the fruits of Ammi visnaga (L.) Lam. They were identified as khellin, visnagin, and khellol glycoside by interpretation of spectral analyses. Quantitative determination of furanochromones in A. visnaga (L.) ripe fruits from Hatay region (Turkey) was carried out by ultraviolet spectrophotometry and gas chromatography. In addition, photochemical properties of furanochromones and chemical composition of essential oil were determined.

Resveratrol and two monomethylated stilbenes from Israeli Rumex bucephalophorus and their antioxidant potential

The roots of Rumex bucephalophorus were analyzed for resveratrol and analogues. Two stilbene-O-methyl derivatives were identified, in addition to resveratrol (3,5,4'-trihydroxystilbene). The stilbene-O-methyl derivatives were shown to be 5,4'-dihydroxy-3-methoxystilbene and 3,5-dihydroxy-4'-methoxystilbene. The antioxidant capacities of all these stilbenes were determined.