Four new phenolic constituents from the roots of Rumex dentatus L.

Four new phenolic compounds, including two naphthalenes, musizin-8-O-ß-D-(6'-O-malonyl-3''-methoxy)glucopyranoside (1) and 2-acetyl-3-methyl-1,4-naphtho-quinone-8-O-ß-D-glucopyranoside (2), one chromone, (2'R)-7-hydroxy-2-(2'-hydroxypropyl)-5-methyl acetate chromone (3), and one xanthone, 2,8-dimethyl-3,6-dihydroxyxanthone (4) were isolated from the roots of Rumex dentatus L. (Polygonaceae). In addition, five known including four naphthalenes (5-8) and one chromone (9) were also obtained. Their structures were determined by means of extensive spectroscopic analysis and acidic hydrolysis. Compound 1 showed moderate antifungal activity against Epidermophyton floccosum, with inhibitory rate of 39.539 ± 0.412% at a concentration of 100 µM.

HPLC-DAD-MS3 fingerprints of phenolics of selected Polygonum taxa and their chemometric analysis.

Many Polygonaceae taxa such as Bistorta officinalis, Persicaria amphibia, Persicaria hydropiper, Persicaria lapathifolia, Persicaria maculosa, Persicaria mitis, Polygonum aviculare occur naturally in the entire territory of Poland and are also common in other European countries. Many of these species are also utilised as medicinal plants. In this manuscript we establish the phytochemical profiles of selected taxa from the Polygonaceae focusing on phenolics. Additionally, we try to find chemophenetic markers for the species investigated. Compounds were detected and characterised based on HPLC-DAD-MS data, quantified, and furtherly analysed using multivariate analyses. Chemophenetic markers were identified also considering previous literature.

Microencapsulation of Phenolic Extract from Sea Grape (Coccoloba uvifera L.) with Antimutagenic Activity.

This study aimed to microencapsulate the sea grape ethanolic extract by the spray drying process, characterizing the obtained powder, and evaluating its antimutagenicity activity. Microparticles showed a mean size of 6.28 µm and a spherical shape with a smooth surface. The powder had a low moisture content (4.02±0.92 %) and water activity (0.27±0.01), and high solubility (76±3.60 %). Moreover, hygroscopicity (14.75±2.63 g/100 g of powder) and bulk density (0.63±0.03 g/cm3 ) values suggested that this powder can be easily handled at a pilot or industrial scale. In addition, microencapsulation protected the extract against oxidation by ultraviolet light, improved its thermal stability, and its antimutagenicity activity was similar to fresh sea grape extract. In conclusion, the microencapsulation with maltodextrin by spray drying technique is an alternative to protect bioactive compounds from sea grapes against environmental conditions, maintaining their antimutagenic activity.

Indigo Pulverata Levis (Chung-Dae, Persicaria tinctoria) Alleviates Atopic Dermatitis-like Inflammatory Responses In Vivo and In Vitro.

Atopic dermatitis (AD) is a chronic inflammatory skin disease associated with a type 2 T helper cell (Th2) immune response. The IndigoPulverata Levis extract (CHD) is used in traditional Southeast Asian medicine; however, its beneficial effects on AD remain uninvestigated. Therefore, we investigated the therapeutic effects of CHD in 2,4-dinitrochlorobenzene (DNCB)-induced BALB/c mice and tumor necrosis factor (TNF)-α- and interferon gamma (IFN)-γ-stimulated HaCaT cells. We evaluated immune cell infiltration, skin thickness, and the serum IgE and TNF-α levels in DNCB-induced AD mice. Moreover, we measured the expression levels of pro-inflammatory cytokines, mitogen-activated protein kinase (MAPK), and the nuclear factor-kappa B (NF-κB) in the mice dorsal skin. We also studied the effect of CHD on the translocation of NF-κB p65 and inflammatory chemokines in HaCaT cells. Our in vivo results revealed that CHD reduced the dermis and epidermis thicknesses and inhibited immune cell infiltration. Furthermore, it suppressed the proinflammatory cytokine expression and MAPK and NF-κB phosphorylations in the skin tissue and decreased serum IgE and TNF-α levels. In vitro results indicated that CHD downregulated inflammatory chemokines and blocked NF-κB p65 translocation. Thus, we deduced that CHD is a potential drug candidate for AD treatment.

HPLC-DAD phenolics analysis, α-glucosidase, α-amylase inhibitory, molecular docking and nutritional profiles of Persicaria hydropiper L.

BACKGROUND: Natural phenolic compounds and Phenolics-rich medicinal plants are also of great interest in the management of diabetes. The current study was aimed to analyze phenolics in P. hydropiepr L extracts via HPLC-DAD analysis and assess their anti-diabetic potentials using in-vitro and in-silico approaches. METHODS: Plant crude methanolic extract (Ph.Cme) was evaluated for the presence of phenolic compounds using HPLC-DAD analysis. Subsequently, samples including crude (Ph.Cr), hexane (Ph.Hex), chloroform (Ph.Chf), ethyl acetate (Ph.EtAc), butanol (Ph.Bt), aqueous (Ph.Aq) and saponins (Ph.Sp) were tested for α-glucsidase and α-amylase inhibitory potentials and identified compounds were docked against these target enzymes using Molecular Operating Environment (MOE) software. Fractions were also analyzed for the nutritional contents and acute toxicity was performed in animals. RESULTS: In HPLC-DAD analysis of Ph.Cme, 24 compounds were indentfied and quantified. Among these, Kaemferol-3-(p-coumaroyl-diglucoside)-7-glucoside (275.4 mg g- 1), p-Coumaroylhexose-4-hexoside (96.5 mg g- 1), Quercetin-3-glucoronide (76.0 mg g- 1), 4-Caffeoylquinic acid (58.1 mg g- 1), Quercetin (57.9 mg g- 1), 5,7,3'-Trihydroxy-3,6,4',5'-tetramethoxyflavone (55.5 mg g- 1), 5-Feruloylquinic acid (45.8 mg g- 1), Cyanidin-3-glucoside (26.8 mg g- 1), Delphinidin-3-glucoside (24 mg g- 1), Quercetin-3-hexoside (20.7 mg g- 1) were highly abundant compounds. In α-glucosidase inhibition assay, Ph.Sp were most effective with IC50 value of 100 µg mL-1. Likewise in α-amylase inhibition assay, Ph.Chf, Ph.Sp and Ph.Cme were most potent fractions displayed IC50 values of 90, 100 and 200 µg mL-1 respectively. Docking with the α-glucosidase enzyme revealed top ranked conformations for majority of the compounds with Kaemferol-3-(p-coumaroyl-diglucoside)-7-glucoside as the most active compound with docking score of - 19.80899, forming 14 hydrogen bonds, two pi-H and two pi-pi linkages with the Tyr 71, Phe 158, Phe 177, Gln 181, Arg 212, Asp 214, Glu 276, Phe 300, Val 303, Tyr 344, Asp 349, Gln 350, Arg 439, and Asp 408 residues of the enzyme. Likewise, docking with α-amylase revealed that most of the compounds are well accommodated in the active site residues (Trp 59, Tyr 62, Thr 163, Leu 165, Arg 195, Asp 197, Glu 240, Asp 300, His 305, Asp 356) of the enzyme and Cyanidin-3-rutinoside displayed most active compound with docking score of - 15.03757. CONCLUSIONS: Phytochemical studies revealed the presence of highly valuable phenolic compounds, which might be responsible for the anti-diabetic potentials of the plant samples.

Rapid Screening Alpha-Glucosidase Inhibitors from Polygoni Vivipari Rhizoma by Multi-Step Matrix Solid-Phase Dispersion, Ultrafiltration and HPLC.

Polygoni Vivipari Rhizoma (PVR), the dried root of Polygonum viviparum, has been used as herbal medicine in China for a long time. In the present study, a new method based on multi-step matrix solid-phase dispersion (MSPD), ultrafiltration and high performance liquid chromatography (HPLC) for screening alpha-glucosidase inhibitors (AGIs) from PVR was proposed. First, three different PVR extractions were prepared by multi-step MSPD with 15% methanol, 60% methanol and 100% methanol. Second, the alpha-glucosidase inhibition tests for the three extracts were carried out, and the 60% methanol extraction showed the best activity. Then, the AGIs screening experiment was performed with ultrafiltration and HPLC analysis using the 60% methanol extraction. Seven binding components (quercetin-3-O-vicianoside, quercetin 3-O-neohesperidoside, rutin, hyperoside, quercetin 3-O-glucuronide, luteolin-7-O-neohesperidoside, kaempferol 3-glucuronide) were found. These seven components were further validated as the AGIs by molecular docking analysis. The developed method was a rapid and efficient tool for screening AGIs from PVR, which provided scientific data for the bioactive components study of PVR.

An Update on Phytochemicals and Pharmacological Activities of the Genus Persicaria and Polygonum.

The discovery of new pharmaceutical identities, particularly anti-infective agents, represents an urgent need due to the increase in immunocompromised patients and the ineffectiveness/toxicity of the drugs currently used. The scientific community has recognized in the last decades the importance of the plant kingdom as a huge source of novel molecules which could act against different type of infections or illness. However, the great diversity of plant species makes it difficult to select them with probabilities of success, adding to the fact that existing information is difficult to find, it is atomized or disordered. Persicaria and Polygonum constitute two of the main representatives of the Polygonaceae family, which have been extensively used in traditional medicine worldwide. Important and structurally diverse bioactive compounds have been isolated from these genera of wild plants; among them, sesquiterpenes and flavonoids should be remarked. In this article, we firstly mention all the species reported with pharmacological use and their geographical distribution. Moreover, a number of tables which summarize an update detailing the type of natural product (extract or isolated compound), applied doses, displayed bioassays and the results obtained for the main bioactivities of these genera cited in the literature during the past 40 years. Antimicrobial, antioxidant, analgesic and anti-inflammatory, antinociceptive, anticancer, antiviral, antiparasitic, anti-diabetic, antipyretic, hepatoprotective, diuretic, gastroprotective and neuropharmacological activities were explored and reviewed in this work, concluding that both genera could be the source for upcoming molecules to treat different human diseases.

Persicaria strigosa (R.Br.) Nakai: a natural anthelmintic?

Persicaria strigosa (R.Br.) Nakai. (Family Polygonaceae) is an important plant of Assam, having several ethnobotanical uses. Tribal communities consume leaf extracts to cure helminth infection. The present study investigated the antioxidant, phytochemicals, and anthelmintic activity of P. strigosa. Total phenolic and flavonoid contents were estimated following standard methods. Antioxidant properties were analyzed by TAC, FRAP, DPPH, ABTS, and TBARS assays. Anthelmintic activity of plant was investigated in Paramphistomum sp. treated with 5 mg/mL, and paralysis and death times were recorded. The most potent solvent extract was performed GC-MS analysis to identify the phytocompounds. Plant extract-treated parasites were further analyzed for biochemical changes. Additionally, molecular docking was performed to study the binding affinities between phytocompounds and enzymes. P. strigosa showed rich phenolics, flavonoids, and antioxidant properties. Ethyl acetate and methanolic extracts showed more powerful antioxidant properties than other extracts. In vitro anthelmintic study found ethyl acetate and diethyl ether the most active extracts. Treated parasites showed a significant decrease in enzyme activity. The highest inhibition was observed in AchE, followed by MDH, LDH, ALP, and ACP. GC-MS study identified 12 probable compounds from the ethyl acetate extract of P. strigosa. Molecular docking showed the strongest binding affinity between the phytocompounds and AchE enzyme (- 7.6 kcal/mol). Overall, compounds C6, C7, and C12 showed better binding affinity compared to other compounds. The in vitro helminth bioassays and biochemical analysis suggest Persicaria strigosa a possible anthelmintic agent. However, isolation and characterization of bioactive compound(s) may promise new drug candidates for helminth infections.

Screening of antioxidant and tyrosinase inhibition activities of spicy vegetables in Vietnam and application of Persicaria odorata leaf extract to preservative white leg shrimp (Litopenaus vannamei).

In this study, we aimed to exploit natural extracts from the spicy vegetables, which are rich in phenolic compounds as an initial treatment step in the cold storage process for shrimp. Firstly, 40 extracts from 10 types of spicy vegetables in Vietnam were prepared and tested for their bioactivities. Among samples, the extract from Persicaria Odorata leaves (E-4) exhibited the highest potential of scavenging DPPH free radical (IC50 of 7.54 µg.mL-1) and decreasing tyrosinase activity with the inhibition percentage of 54.2 % at the concentration of 100 mg/mL. Twenty-two out of a total of 36 chemical compounds in the E-4 extract identified using HPLC-MS technique were phenolic compounds, in which four compounds (morin, quercetin, fisetin, astragalin) are flavonoids. Shrimp (Litopenaus vannamei) samples were treated with the E-4 extract having lower gray values, lipid peroxidation values, and microbiological counts than those of the control samples after 7 days of storage at 2 oC. These results show the potential of using the natural extract as a safe and effective alternative for commercial chemical-derived preservatives in the shrimp storage process.

Genus Triplaris (Polygonaceae): A review on traditional medicinal use, phytochemistry and biological activities.

ETHNOPHARMACOLOGICAL RELEVANCE: The genus Triplaris (Polygonaceae) comprises approximately 25 species distributed throughout South and Central America. Some species have been used in folk medicine, mainly, to treat malaria, leishmaniasis, diarrheia, dysenteria, pain and inflammation. AIM OF THE STUDY: The purpose of this review is to provide information on the traditional uses, phytochemistry and known biological activities of Triplaris, an important genus for South America research groups on medicinal plants, in order to explore its therapeutic potential to direct future research in the search for new bioactive molecules. MATERIALS AND METHODS: The available information on the genus Triplaris was gathered from scientific databases (LILACS, Pubmed, SciELO, Science Direct, Scopus, CAPES Periodicals Portal and Theses and Dissertations Catalog) before March 2020 using the keyword "Triplaris". Works related to traditional uses, phytochemistry and biological activities of plants were included in this review. RESULTS: Most of the studies involving Triplaris were conducted by research groups located in Brazil, Peru e Bolivia. Probably, because the genus has been used in folk medicine only by these countries. Regarding the annual evolution of the publications, a larger number of articles published in 2010 were observed. Flavonols represent the main classe of secondary metabolites from Triplaris. In terms of the pharmacological investigations, T. americana and T. gardneriana are considered the most studied species, with extensive promising biological activities. The pharmacological activities can be attributed to bioactive phytochemicals. CONCLUSIONS: All findings indicate that Triplaris is an important genus of the Polygonaceae family. However, considering its chemical and pharmacological importance, the studies developed with Triplaris species are still limited, representing an opportunity to investigate new bioactive molecules and extracts. The review shows that little pre-clinical or in vivo research is available to prove the ethnopharmacological records in the genre. Therefore, this review encourages further studies on Triplaris in the search for a wide range of therapeutic products.

Review on Pharmacological and Phytochemical Prospects of Traditional Medicinal Plant: Persicaria hydropiper (Smartweed).

Persicaria hydropiper (L.) Delarbre (family Polygonacea), commonly known as Polygonum hydropiper, is a popular medicinal plant used in traditional medicine. The plant is indigenous to the tropical northern hemisphere and temperate zone, including China, Bangladesh, India, and Japan. The plant is used in folk medicine for numerous ailments such as hemorrhoids, antifertility, diarrhea, and dyspepsia. Its medicinal usage in Unani, Ayurveda, Siddha, and other traditional medicine is well-recognized. So far, a wide range of active phytochemicals of this plant has been identified, such as flavonoids, sulphated flavonoids, terpenoids, anthraquinones, steroids, coumarin, simple phenolics, and others. Pharmacological data reported in the literature suggest that various parts of P. hydropiper exhibit antimicrobial, antioxidant, hypoglycemic, antidepressant, cardioprotective, hepatoprotective, anticancer, and antifertility effects. The present review aims to compile the coherently document research on the phytochemical, pharmacological, and biological activities of P. hydropiper from different parts of the globe.

Chemical and Pharmacological Potential of Coccoloba cowellii, an Endemic Endangered Plant from Cuba.

Coccoloba cowellii Britton (Polygonaceae) is an endemic and critically endangered plant that only grows in Camagüey, a province of Cuba. In this study, a total of 13 compounds were identified in a methanolic leaf extract, employing a dereplication of the UHPLC-HRMS data by means of feature-based molecular networking (FBMN) analysis in the Global Natural Products Social Molecular Network (GNPS), together with the interpretation of the MS/MS data and comparison with the literature. The major constituents were glucuronides and glycosides of myricetin and quercetin, as well as epichatechin-3-O-gallate, catechin, epicatechin and gallic acid, all of them being reported for the first time in C. cowellii leaves. The leaf extract was also tested against various microorganisms, and it showed a strong antifungal effect against Candida albicans ATCC B59630 (azole-resistant) (IC50 2.1 µg/mL) and Cryptococcus neoformans ATCC B66663 (IC50 4.1 µg/mL) with no cytotoxicity (CC50 > 64.0 µg/mL) on MRC-5 SV2 cells, determined by the resazurin assay. Additionally, the extract strongly inhibited COX-1 and COX-2 enzyme activity using a cell-free experiment in a dose-dependent manner, being significantly more active on COX-1 (IC50 4.9 µg/mL) than on COX-2 (IC50 10.4 µg/mL). The constituents identified as well as the pharmacological activities measured highlight the potential of C. cowellii leaves, increasing the interest in the implementation of conservation strategies for this species.

Antimutagenic, Antiproliferative and Antioxidant Properties of Sea Grape Leaf Extract Fractions (Coccoloba uvifera L.).

BACKGROUND: Cancer is a disease characterized by the invasion and uncontrolled growth of cells. One of the best ways to minimize the harmful effects of mutagens is through the use of natural antimutagens. In this regard, the search for new antimutagens that act in the chemoprevention could represent a promising field in this area. OBJECTIVE: In this study biological potential of 11 fractions from Coccoloba uvifera L. leaf hexane extract was evaluated by several in vitro tests. METHODS: Leaves were lyophilized and hexane extraction was performed. The extract was fractionated by column chromatography with hexane, ethyl acetate, and methanol. The antimutagenic (Ames test), antiproliferative (MTT test), and antioxidant capacity (DPPH, ABTS, and ferrous ion chelation) of the fractions were evaluated. RESULTS: Fractions 4, 6, 8, and 9 have antimutagenic activity (against sodium azide in strain TA100), fraction 11 showed antiproliferative capacity (IC50 of 24 ± 9 µg/mL in cells of HCT 116). The fractions with the highest activity were analyzed by HPLC-MS and lupeol, acacetin, and ß-sitosterol were identified. CONCLUSION: This study demonstrates, for the first time, the bioactivity of C. uvifera leaf as a new source of High Biological Value Compounds (HBVC), which can be of interest to the food and pharmaceutical industries.

Efficient Separation of Phytochemicals from Muehlenbeckia volcanica (Benth.) Endl. by Polarity-Stepwise Elution Counter-Current Chromatography and Their Antioxidant, Antiglycation, and Aldose Reductase Inhibition Potentials.

Muehlenbeckia volcanica (Benth.) Endl. (M. volcanica), native to South America, is a traditional Peruvian medicinal plant that has multi-therapeutic properties; however, no phytochemicals have been identified from it yet. In this study, a five-step polarity-stepwise elution counter-current chromatography (CCC) was developed using methanol/water (1:5, v/v) as the stationary phase and different ratios of n-hexane, ethyl acetate, and n-butanol as mobile phases to separate the compounds from the 70% methanol extract of M. volcanica, by which six compounds with a wide range of polarities were separated in a single run of CCC and were identified as gallic acid, protocatechuic acid, 4,4'-dihydroxy-3,3'-imino-di-benzoic acid, rutin, quercitrin, and quercetin. Then, two compounds from the fractions of stepwise elution CCC were separated using conventional high-speed CCC, pH-zone-refining CCC, and preparative high-performance liquid chromatography, and identified as shikimic acid and miquelianin. These compounds are reported from M. volcanica for the first time. Notably, except for shikimic acid, all other compounds showed anti-diabetic potentials via antioxidant, antiglycation, and aldose reductase inhibition. The results suggest that the polarity-stepwise elution CCC can be used to efficiently separate or fractionate compounds with a wide range of polarities from natural products. Moreover, M. volcanica and its bioactive compounds are potent anti-diabetic agents.

Ellagitannins and Oligomeric Proanthocyanidins of Three Polygonaceous Plants.

The aim of this study was to characterize hydrolyzable tannins in Polygonaceous plants, as only a few plants have previously been reported to contain ellagitannins. From Persicaria chinensis, a new hydrolyzable tannin called persicarianin was isolated and characterized to be 3-O-galloyl-4,6-(S)-dehydrohexahydroxydiphenoyl-d-glucose. Interestingly, acid hydrolysis of this compound afforded ellagic acid, despite the absence of a hexahydroxydiphenoyl group. From the rhizome of Polygonum runcinatum var. sinense, a large amount of granatin A, along with minor ellagitannins, helioscpoinin A, davicratinic acids B and C, and a new ellagitannin called polygonanin A, were isolated. Based on 2D nuclear magnetic resonance (NMR) spectroscopic examination, the structure of polygonanin A was determined to be 1,6-(S)-hexahydroxydiphenoyl-2,4-hydroxychebuloyl-ß-d-glucopyranose. These are the second and third hydrolyzable tannins isolated from Polygonaceous plants. In addition, oligomeric proanthocyanidins of Persicaria capitatum and P. chinensis were characterized by thiol degradation. These results suggested that some Polygonaceous plants are the source of hydrolyzable tannins not only proanthocyanidins.

Phytochemical identification and quantification of quercetin in Triplaris gardneriana wedd. leaves by HPLC-DAD with evaluation of antibacterial activity.

Triplaris gardneriana is used by traditional medicine. The objective of this work was the leaves chemical study with isolate, identify and quantify the chemical constituent, validate the analytical method and evaluate the antibacterial activity. The ethyl acetate and chloroform fractions were subjected to column chromatography for isolation of the compounds quercetin and lupeol, respectively. For the identification, quantification of quercetin in the samples and validation of method were performed using HPLC-DAD. The antibacterial activity was evaluated by the microdilution method. The isolated phytochemicals are being reported for the first time in the species. The ethyl acetate fraction showed a higher content of quercetin with 9.967 ± 1.01 mg.g-1. The method was validated. The samples showed good antibacterial activity. In this study, quercetin was isolated and quantified in the species being a great alternative as a producer of this secondary metabolite, which can be safely applied in the quality control analysis.

Coccoloba alnifolia Leaf Extract as a Potential Antioxidant Molecule Using In Vitro and In Vivo Assays.

The genus Coccoloba is widely used in traditional folk medicine, but few scientific data exist for this genus. The goal of this study was to characterise the chemical composition and antioxidant activities of C. alnifolia leaf extracts using in vitro and in vivo assays. Six extracts were obtained: hexane (HE), chloroform (CE), ethanol (EE), methanol (ME), water end extract (WEE), and water extract (WE). Thin-layer chromatography (TLC) analysis showed the presence of phenols, saponins, terpenes, and flavonoids. In vitro assays demonstrated substantial antioxidant potential, especially for polar extracts (EE, ME, WEE, and WE). Moreover, no toxic effects were observed on mammalian cell lines for most of the extracts at the concentrations evaluated. The nematode Caenorhabditis elegans was also used as an in vivo model for testing antioxidant potential. The EE and WE were chosen, based on previously obtained results. It was observed that neither the EE nor the WE had any toxic effect on C. elegans development. Additionally, the antioxidant potential was evaluated using tert-butyl hydroperoxide as a stressor agent. The EE increased the life span of C. elegans by 28% compared to that of the control, and the WE increased the range to 39.2-41.3%. High-performance liquid chromatography (HPLC-DAD) showed the presence of gallic acid, p-coumaric acid, and vitexin in the WE. Therefore, in vitro and in vivo data demonstrated the antioxidant potential of C. alnifolia extracts and their possible biotechnological applications.

Screening of an Endophyte Transforming Polydatin to Resveratrol from Reynoutria Japonica Houtt and the Optimization of Its Transformation Parameters.

Resveratrol showed various kinds of bioactivities, such as antioxidant, antimicrobial, anticancer effects and, therefore, has been used widely as an important ingredient in medication, healthy foods and cosmetics. However, in nature, resveratrol usually exists at low content and more often exists as polydatin. Therefore, it becomes important to find the cost-effective and environmental-friendly way to transform polydatin to resveratrol. In this study, endophytes were isolated from the rhizome tissue of Reynoutria japonica and screened for transforming polydatin to resveratrol using reversed-phase high-performance liquid chromatography (RP-HPLC) and confirmed by liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) spectroscopy. A bacterium identified as Bacillus aryabhattai using 16S rRNA phylogenetic tree analysis showed highest transformation rate. The transforming conditions were optimized including substrate concentration, substrate addition time, culture temperature and inoculation ratio. Our results demonstrated that the bacteria isolated from R. japonica rhizome tissue showed high activity in transforming polydatin into resveratrol. Crude extract of R. japonica root and rhizome (RJE) was also tested as substrate and it was found that the transformation was significantly inhibited at 10.0 mg/mL RJE. Emodin at equivalent concentration of 10.0 mg/mL RJE showed no inhibition activity, and glucose content in RJE was trace and far from enough to exhibit the inhibitory activity. Successive solvent partition followed by an inhibition activity assay revealed that the ethyl acetate fraction showed the main inhibition activity. However, due to the coexistence of polydatin and compounds with inhibitory activity, the concentration of RJE can only be used at limited concentration as substrate.

Phenolic Fingerprinting, Antioxidant, and Deterrent Potentials of Persicaria maculosa Extracts.

Persicaria maculosa (Polygonaceae) (known as lady's thumb) is an annual morphologically variable weed that is widely distributed in Chile. The purpose of this study was to investigate the antifeedant potential of methanolic (MeOH), ethanolic (EtOH), and dichloromethane (DCM) extracts from the aerial parts of this plant collected in the Valparaíso and Curicó provinces (Chile) and relate this activity to the antioxidant capacity and the presence of phenolic compounds in the extracts. A phenolic profile based on HPLC-ESI-MS/MS allowed the identification of 26 phenolic compounds, most of them glycosyl derivatives of isorhamnetin, quercetin, and kaempferol. In addition, the total phenolic content (TP), total flavonoids (TF), and antioxidant activity measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide anion scavenging (O2-), ferric-reducing antioxidant power (FRAP), and cupric-reducing antioxidant capacity (CUPRAC) of the extracts are reported. The antifeedant potentials of the plant extracts were tested against Epilachna paenulata, Pseudaletia adultera, Macrosiphum euphorbiae, and Diaphorina citri insects for the first time. The activity against the aphid M. euphorbiae was significant for the DCM extracts of plants from Valparaíso and Curicó (settling % = 23% ± 4% and 23% ± 5%, respectively). The antifeedant activities against the beetle E. paenulata and the lepidoptera P. adultera were significant for Valparaíso extracts, especially when tested against E. Paenulata (IFP = 1.0 ± 0.0). Finally, the MeOH and EtOH extracts from Valparaíso plants reduced the diet consumption of the psilid D. citri (p < 0.05). The results showed that P. maculosa is a good source of flavonoids with some antioxidant capacities and has potential interest as botanical eco-friendly alternative with deterrent activity.

Flavonoid, stilbene and diarylheptanoid constituents of Persicaria maculosa Gray and cytotoxic activity of the isolated compounds.

Persicaria maculosa (Polygonaceae) has been used as edible and as medicinal plant since ancient times. As a result of multistep chromatographic purifications, chalcones [2'-hydroxy-3',4',6'-trimethoxychalcone (1), pashanone (2), pinostrobin chalcone (3)], flavanones [6-hydroxy-5,7-dimethoxyflavanone (4), pinostrobin (5), onysilin (6), 5-hydroxy-7,8-dimethoxyflavanone (7)], flavonol [3-O-methylgalangin (8)], stilbene [persilben (9)], diarylheptanoids [1,7-diphenylhept-4-en-3-one (10), dihydroyashabushiketol (12), yashabushidiol B (13)] and 3-oxo-α-ionol-glucoside (11) were isolated from P. maculosa. The present paper reports for the first time the occurrence of diarylheptanoid-type constituents in the family Polygonaceae. Cytotoxicity of 1-5, 7 and 9-11 on 4 T1 mouse triple negative breast cancer cells was assayed by MTT test. None of the tested compounds reduced the cell viability to less than 80% of the control. On non-tumorigenic D3 human brain endothelial cells the decrease of cell viability was observed in case of 1 and 2. Further impedance measurements on 4 T1 and D3 cells a concentration-dependent decrease in the cell index of both cell types was demonstrated for 1, while 2 proved to be toxic only on endothelial cells.