Kaempferol acetylrhamnosides from the rhizome of Dryopteris crassirhizoma and their inhibitory effects on three different activities of human immunodeficiency virus-1 reverse transcriptase

Anticoronavirus activity of rhizome of Dryopteris crassirhizoma via multistage targeting of virus entry and viral proteases, Mpro and PLpro

ETHNOPHARMACOLOGICAL RELEVANCE

The rhizome of Dryopteris crassirhizoma Nakai (Dryopteridaceae, RDC), a traditional East Asian herbal medicine, possesses a broad spectrum of medicinal properties, including anti-inflammatory, anticancer, antibacterial, and antiviral activities.

AIM OF THE STUDY

This study investigates the 30% ethanolic extract of RDC's antiviral potential against human coronavirus OC43 (HCoV-OC43), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and its variants infections.

MATERIALS AND METHODS

A 30% ethanolic extract of RDC or its components, filixic acid ABA (PubChem CID: 15081408) and dryocrassin ABBA (PubChem CID: 3082025) were treated with Human Coronavirus infection (HCoV-OC43, SARS-CoV-2 and its variants). The base peak chromatogram of RDC was evaluated using UPLC-Q/TOF Mass to identify the RDC, and the quantitative analysis of RDC compounds was performed using LC-MS/MS. A cytopathic effect (CPE) reduction assay, Western blot, immunofluorescence staining of viral protein expression, and qRT-PCR were performed to quantify the viral RNA copy numbers and determine the antiviral activity. The time-of-addition assay, the virus attachment, penetration, and virucidal assays, and SARS-CoV-2 Mpro and PLpro activity assay were used to elucidate the mode of action.

RESULTS

RDC exhibited dose-dependent inhibition of HCoV-OC43-induced cytopathic effects, reducing viral RNA copy numbers and viral protein levels. Time-of-addition assays indicated that RDC targets the early stages of the HCoV-OC43 life cycle, inhibiting virion attachment and penetration with virucidal activity. Notably, filixic acid ABA and dryocrassin ABBA, constituents of RDC, reduced HCoV-OC43 viral RNA loads. Furthermore, RDC effectively blocked viral entry in pseudotyped lentivirus assays, involving spike proteins of SARS-CoV-2 Delta plus and South Africa variants, as well as control lentiviral particles expressing vesicular stomatitis virus glycoprotein G. Additionally, RDC demonstrated inhibition of SARS-CoV-2 infection and its variants by targeting viral proteases, namely main protease (Mpro) and papain-like protease (PLpro).

CONCLUSIONS

These findings underscore RDC's multistage approach to targeting viral infections by impeding virus entry and inhibiting viral protease activity. Therefore, RDC holds promise as a potent, broad-spectrum anticoronaviral therapeutic agent.

Phytochemical investigation of aerial parts of Woodsia ilvensis and its plasmin-inhibitory activity in vitro

The fern plant Woodsia ilvensis (L.) R. Br. belongs to the Woodsiaceae family and its leaves are used to treat diarrhea, soft-tissue injuries, and external injuries. Investigations of the compounds obtained from the plasmin-inhibitory-active extracts of W. ilvensis led to the isolation of two undescribed maleimide N-glycosides, an undescribed stilbenoid glycoside, and five undescribed acetylated flavonol bisdesmosides, together with 19 known compounds. The chemical structures of the isolated compounds were determined using spectroscopy. The absolute configurations of the sugar moieties were determined via HPLC after acid hydrolysis. Among the isolated compounds, some flavonoids and stilbenoid glycosides exhibited plasmin-inhibitory activity.

Identification and Comparison of Bioactive Components of Two Dryopteris sp. Extract Using LC-QTOF-MS

Dryopteris sp. is known for its various pharmacological effects and is used as a traditional medicine in Asia. The present study investigated the chemical composition and antimicrobial activity of Dryopteris sp. distributed in Korea. The chemical compounds in the ethanolic extracts of Dryopteris lacera and Dryopteris bissetiana were investigated by ultra-high performance liquid chromatography-quadrupole time-of-flight-mass spectrometry analysis and identified by exploring the UNIFI traditional medicine library. Flavonoids such as juglanin, 6-hydroxyluteolin 7-O-laminaribioside, peltatoside, kaempferitrin, hyperoside, and astragalin were identified in both D. lacera and D. bissetiana. Neochlorogenic acid was identified as a caffeoylquinic acid in D. bissetiana. Both extracts of D. lacera and D. bissetiana exhibited antibacterial activity against Gram-positive pathogens, Staphylococcus aureus and Streptococcus mutans. The minimum inhibitory concentration of D. bissetiana against S. aureus was less than 625 ppm. The antibacterial activity was attributed to the identified phenolic compounds, juglanin, 6-hydroxyluteolin 7-O-laminaribioside, kaempferitrin, astragalin, and neochlorogenic acid. Therefore, D. lacera and D. bissetiana can be used as Gram-positive selective antibiotics for further investigation.

An Investigation of the Anti-Depressive Properties of Phenylpropanoids and Flavonoids in Hemerocallis citrina Baroni

The World Health Organization predicts that over the next several years, depression will become the most important mental health issue globally. Growing evidence shows that the flower buds of Hemerocallis citrina Baroni (H. citrina) possess antidepressant properties. In the search for new anti-depression drugs, a total of 15 phenylpropanoids and 22 flavonoids were isolated and identified based on spectral data (1D and 2D NMR, HR-ESI-MS, UV) from H. citrina. Among them, compound 8 was a novel compound, while compounds 1-4, 6, 9, 10, 15, 17, 24-26, 28, and 37 were isolated for the first time from Hemerocallis genus. To study the antidepressant activity of phenylpropanoids and flavonoids fractions from H. citrina, macroporous resin was used to enrich them under the guidance of UV characteristics. UHPLC-MS/MS was applied to identify the constituents of the enriched fractions. According to behavioral tests and biochemical analyses, it showed that phenylpropanoid and flavonoid fractions from H. citrina can improve the depressive-like mental state of chronic unpredictable mild stress (CUMS) rats. This might be accomplished by controlling the amounts of the inflammatory proteins IL-6, IL-1β, and TNF-α in the hippocampus as well as corticosterone in the serum. Thus, the monomer compounds were tested for their anti-neuroinflammatory activity and their structure-activity relationship was discussed in further detail.

Anticoronaviral Activity of the Natural Phloroglucinols, Dryocrassin ABBA and Filixic Acid ABA from the Rhizome of Dryopteris crassirhizoma by Targeting the Main Protease of SARS-CoV-2

The rhizome of Dryopteris crassirhizoma Nakai. (Dryopteridaceae) has been used in traditional medicine in East Asia and has recently been reported to have anticancer, anti-inflammation, and antibacterial activity as well as antiviral activity. Natural phloroglucinols from D. crassirhizoma, dryocrassin ABBA and filixic acid ABA were reported to inhibit influenza virus infection with an inhibitory activity on neuraminidase. In this study, we found that dryocrassin ABBA and filixic acid ABA have an inhibitory activity against the main protease of SARS-CoV-2. Therefore, dryocrassin ABBA and filixic acid ABA exhibited inhibitory activity against SARS-CoV-2 infection in Vero cells dose-dependently using the immunofluorescence-based antiviral assays. Moreover, these compounds inhibited SARS-CoV and MERS-CoV infection, suggesting their broad-spectrum anticoronaviral activity. In addition, a 5-day repeated-dose toxicity study of dryocrassin ABBA and filixic acid ABA suggested that an approximately lethal dose of these compounds in mice was >10 mg/kg. Pharmacokinetic studies of dryocrassin ABBA showed good microsomal stability, low hERG inhibition, and low CYP450 inhibition. In vivo pharmacokinetic properties of dryocrassin ABBA showed a long half-life (5.5–12.6 h) and high plasma exposure (AUC 19.3–65 μg·h/mL). Therefore, dryocrassin ABBA has therapeutic potential against emerging coronavirus infections, including COVID-19.

Nanotechnology Applications of Flavonoids for Viral Diseases

Recent years have witnessed the emergence of several viral diseases, including various zoonotic diseases such as the current pandemic caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Other viruses, which possess pandemic-causing potential include avian flu, Ebola, dengue, Zika, and Nipah virus, as well as the re-emergence of SARS (Severe Acute Respiratory Syndrome) and MERS (Middle East Respiratory Syndrome) coronaviruses. Notably, effective drugs or vaccines against these viruses are still to be discovered. All the newly approved vaccines against the SARS-CoV-2-induced disease COVID-19 possess real-time possibility of becoming obsolete because of the development of ‘variants of concern’. Flavonoids are being increasingly recognized as prophylactic and therapeutic agents against emerging and old viral diseases. Around 10,000 natural flavonoid compounds have been identified, being phytochemicals, all plant-based. Flavonoids have been reported to have lesser side effects than conventional anti-viral agents and are effective against more viral diseases than currently used anti-virals. Despite their abundance in plants, which are a part of human diet, flavonoids have the problem of low bioavailability. Various attempts are in progress to increase the bioavailability of flavonoids, one of the promising fields being nanotechnology. This review is a narrative of some anti-viral dietary flavonoids, their bioavailability, and various means with an emphasis on the nanotechnology system(s) being experimented with to deliver anti-viral flavonoids, whose systems show potential in the efficient delivery of flavonoids, resulting in increased bioavailability.

Novel Anti-Hepatitis B Virus Activity of Euphorbia schimperi and Its Quercetin and Kaempferol Derivatives

Natural or plant products, because of their structural diversity, are a potential source for identifying new anti-hepatitis B virus (HBV) agents. Here, we report the anti-HBV activity of Euphorbia schimperi and its quercetin (QRC) and kaempferol derivatives. The anti-HBV-active methanol fraction of E. schimperi was subjected to chromatographic techniques, leading to isolation of three flavonols, following their structure determination by ¹H and ¹³C NMR spectroscopies. Their cytotoxicity and anti-HBV potential were assessed using HBV reporter HepG2.2.15 cells, and their modes of action were delineated by molecular docking. The isolated compounds identified as quercetin-3-O-glucuronide (Q3G), quercetin-3-O-rhamnoside (Q3R), and kaempferol-3-O-glucuronide (K3G) were non-cytotoxic to HepG2.2.15 cells. The viral HBsAg/HBeAg production on day 5 was significantly inhibited by K3G (∼70.2/∼73.4%), Q3G (∼67.8/∼72.1%), and Q3R (∼63.2%/∼68.2%) as compared to QRC (∼70.3/∼74.8%) and lamivudine (∼76.5/∼84.5%) used as standards. The observed in vitro anti-HBV potential was strongly supported by in silico analysis, which suggested their structure-based activity via interfering with viral Pol/RT and core proteins. In conclusion, this is the first report on the anti-HBV activity of E. schimperi-derived quercitrin-3-O-glucuronide, quercitrin-3-O-rhamnoside, and kaempferol-3-O-glucuronide, most likely through interfering with HBV proteins.

Structural Characterization and Assessment of Anti-Inflammatory and Anti-Tyrosinase Activities of Polyphenols from Melastoma normale

Polyphenols, widely distributed in the genus Melastoma plants, possess extensive cellular protective effects such as anti-inflammatory, anti-tyrosinase, and anti-obesity, which makes it a potential anti-inflammatory drug or enzyme inhibitor. Therefore, the aim of this study is to screen for the anti-inflammatory and enzyme inhibitory activities of compounds from title plant. Using silica gel, MCI, ODS C18, and Sephadex LH-20 column chromatography, as well as semipreparative HPLC, the extract of Melastoma normale roots was separated. Four new ellagitannins, Whiskey tannin C (1), 1-O-(4-methoxygalloyl)-6-O-galloyl-2,3-O-(S)-hexahydroxydiphenoyl-β-d-glucose (2), 1-O-galloyl-6-O-(3-methoxygalloyl)-2,3-O-(S)-hexahydroxydiphenoyl-β-d-glucose (3), and 1-O-galloyl-6-O-vanilloyl-2,3-O-(S)-hexahydroxydiphenoyl-β-d-glucose (4), along with eight known polyphenols were firstly obtained from this plant. The structures of all isolates were elucidated by HRMS, NMR, and CD analyses. Using lipopolysaccharide (LPS)-stimulated RAW2 64.7 cells, we investigated the anti-inflammatory activities of compounds 1-4, unfortunately, none of them exhibit inhibit nitric oxide (NO) production, their IC50 values are all > 50 μM. Anti-tyrosinase activity assays was done by tyrosinase inhibition activity screening model. Compound 1 showed weak tyrosinase inhibitory activity with IC50 values of 426.02 ± 11.31 μM. Compounds 2-4 displayed moderate tyrosinase inhibitory activities with IC50 values in the range of 124.74 ± 3.12-241.41 ± 6.23 μM. The structure-activity relationships indicate that hydroxylation at C-3', C-4', and C-3 in the flavones were key to their anti-tyrosinase activities. The successful isolation and structure identification of ellagitannin provide materials for the screening of anti-inflammatory drugs and enzyme inhibitors, and also contribute to the development and utilization of M. normale.

Propolis and its potential against SARS-CoV-2 infection mechanisms and COVID-19 disease: Running title: Propolis against SARS-CoV-2 infection and COVID-19

Propolis, a resinous material produced by honey bees from plant exudates, has long been used in traditional herbal medicine and is widely consumed as a health aid and immune system booster. The COVID-19 pandemic has renewed interest in propolis products worldwide; fortunately, various aspects of the SARS-CoV-2 infection mechanism are potential targets for propolis compounds. SARS-CoV-2 entry into host cells is characterized by viral spike protein interaction with cellular angiotensin-converting enzyme 2 (ACE2) and serine protease TMPRSS2. This mechanism involves PAK1 overexpression, which is a kinase that mediates coronavirus-induced lung inflammation, fibrosis, and immune system suppression. Propolis components have inhibitory effects on the ACE2, TMPRSS2 and PAK1 signaling pathways; in addition, antiviral activity has been proven in vitro and in vivo. In pre-clinical studies, propolis promoted immunoregulation of pro-inflammatory cytokines, including reduction in IL-6, IL-1 beta and TNF-α. This immunoregulation involves monocytes and macrophages, as well as Jak2/STAT3, NF-kB, and inflammasome pathways, reducing the risk of cytokine storm syndrome, a major mortality factor in advanced COVID-19 disease. Propolis has also shown promise as an aid in the treatment of various of the comorbidities that are particularly dangerous in COVID-19 patients, including respiratory diseases, hypertension, diabetes, and cancer. Standardized propolis products with consistent bioactive properties are now available. Given the current emergency caused by the COVID-19 pandemic and limited therapeutic options, propolis is presented as a promising and relevant therapeutic option that is safe, easy to administrate orally and is readily available as a natural supplement and functional food.

Effects of different pretreatments on flavonoids and antioxidant activity of Dryopteris erythrosora leave

Flavonoids are secondary metabolites of plants that often have medical applications. The influences of different sample drying pretreatments on flavonoids and antioxidant activity of ferns have not studies. Dryopteris erythrosora leaves used to analyze flavonoid alterations resulting from drying pretreatments. The total flavonoid content of D. erythrosora leaves exposed to different pretreatments was significantly different. The total flavonoid content of samples initially air-dried in shade and then oven-dried at 75°C were the highest (7.6%), while samples initially dried at 75°C had the lowest content (2.17%). Antioxidant activities of D. erythrosora leaves with different pretreatments varied. Group B first air-dried in the shade and then oven-dried at 75°C and group C first air-dried in the sun and then oven-dried at 75°C, both showed relatively stronger antioxidant activity. The best pretreatment for preserving the flavonoids was to first dry the plant material in the shade and then complete the drying process in an oven at 75°C. It was tentatively identified 22 flavonoids among the four different pretreatments by HPLC-ESI-TOF-MS.

Medicinal Plants Used in the Treatment of Human Immunodeficiency Virus

Since the beginning of the epidemic, human immunodeficiency virus (HIV) has infected around 70 million people worldwide, most of whom reside is sub-Saharan Africa. There have been very promising developments in the treatment of HIV with anti-retroviral drug cocktails. However, drug resistance to anti-HIV drugs is emerging, and many people infected with HIV have adverse reactions or do not have ready access to currently available HIV chemotherapies. Thus, there is a need to discover new anti-HIV agents to supplement our current arsenal of anti-HIV drugs and to provide therapeutic options for populations with limited resources or access to currently efficacious chemotherapies. Plant-derived natural products continue to serve as a reservoir for the discovery of new medicines, including anti-HIV agents. This review presents a survey of plants that have shown anti-HIV activity, both in vitro and in vivo.

Equisetum telmateia extracts: Chemical compositions, antioxidant activity and antimicrobial effect on the growth of some pathogenic strain causing poisoning and infection

The aerial parts of Equisetum telmateia have been used as a source of biologically active compounds to treat inflammatory, diarrhea, stomach-ache, eczema and mouth infections in traditional medicine. The aim of this work is to evaluate the extraction yield, chemical compositions, antioxidant activity and antimicrobial activity of E. telmateia extracts on Staphylococcus aureus, Bacillus cereus, Escherichia coli, Salmonella typhi and Candida albicans. Chemical compositions E. telmateia was analyzed by high performance liquid chromatography (HPLC) using a C18 column. Analysis of E. telmateia extract by HPLC allowed the identification of Kaempferol 3-O-(6″-O-acetylglucoside) as major compound. The antioxidant activity of extracts was examined by measuring their ability to sequestrate 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. The results showed that the DPPH (IC₅₀ = 70.83 ± 0.2 μg/ml) were obtained in the case of supercritical fluid extraction (SFE) extract. MIC microdilution assay were used to determine the antimicrobial activities. Contrary to lower extraction yield (9.6 ± 0.5), the SFE extract exhibited the highest antimicrobial potency with MIC and MBC values of 32 mg/ml against S. aureus compared to the other extracts. The results suggest that SFE method is more appropriate for extraction of E. telmateia biologically active substances with antimicrobial and antioxidant activity than conventional solvent extraction methods.

Two New Phenolic Glycosides from the Aerial Part of Dryopteris erythrosora

BACKGROUND

Dryopteris erythrosora (D.C. Eaton) Kuntze is a species of fern in the family of Dryopteridaceae, which is distributed throughout East Asia. The genus Dryopteris has been used as traditional medicine, especially to treat hepatitis and protect liver. However, only few studies of chemical constituents of D. erythrosora have been conducted so far.

OBJECTIVE

In this study, we investigated the phytochemical constituents of D. erythrosora.

MATERIALS AND METHODS

The 80% methanol extract of the aerial part of D. erythrosora was used for the isolation of phenolic compounds. The isolated compounds were elucidated by various spectroscopic methods including nuclear magnetic resonance and mass spectrometry.

RESULTS

The present phytochemical investigation on the aerial part of D. erythrosora led to the isolation of two new phenolic glycosides, 1 and 2, as well as nine known flavonoids including two flavones (3 and 4) and seven flavonols (5-11).

CONCLUSION

In this study, two new phenolic glycosides together with nine known flavonoids were isolated from the aerial part of D. erythrosora. Among them, compounds 4, 8, and 11 were isolated for the first time in Dryopteridaceae family from the present investigation. These results helped us to enrich our understanding of the chemical constituents of D. erythrosora and to identify compounds 1 and 2 which could be potential chemotaxonomic markers for the species.

SUMMARY

The genus Dryopteris has been used as traditional medicine, especially to treat hepatitis and protect liverTwo new phenolic glycosides were isolated from D. erythrosoraNine known flavonoids (3-11) were isolated from D. erythrosoraCompounds 4, 8, and 11 were isolated for the first time in Dryopteridaceae family. Abbreviations used: HPLC: High-performance liquid chromatography; Q-TOF LC/MS: Quadrupole-time-of-flight liquid chromatography/mass spectrometry; NMR: Nuclear magnetic resonance; TMS: Tetramethylsilane.

Anti-Influenza Virus (H5N1) Activity Screening on the Phloroglucinols from Rhizomes of Dryopteris crassirhizoma

For screening the active phloroglucinols on influenza virus (H5N1) from Dryopteris crassirhizoma NaKai, a database was established including twenty-three phloroglucinols that had been isolated from Dryopteris crassirhizoma. Their inhibitory effect on the neuraminidase (NA) of influenza virus H5N1 was screened by molecular docking. As a result, three candidates were selected. The rhizomes of D. crassirhizoma were subjected to isolation and purification processes to obtain the inhibitor candidates. Thirteen phloroglucinols were obtained, including three selected candidates and two new phloroglucinols. The five phloroglucinols were investigated for their inhibitory activity on NA in vitro. The results showed that dryocrassin ABBA and filixic acid ABA exhibited inhibitory effects on NA with IC50 as 18.59 ± 4.53 and 29.57 ± 2.48 μM, respectively, and the other three phloroglucinols showed moderate inhibitory activity. Moreover, the anti-influenza virus (H5N1) activity and cytotoxicity of dryocrassin ABBA and filixic acid ABA were tested on Madin-Darby canine kidney (MDCK) cells with the cell counting kit-8 (CCK8) method. The results confirmed that dryocrassin ABBA exhibited an inhibitory activity with low cytotoxicity (TC50 > 400 μM) against influenza virus (H5N1) which will have to be investigated in further detail. In conclusion, phloroglucinols from D. crassirhizoma were shown to have anti-influenza virus activity, and especially dryocrassin ABBA, one of the phloroglucinols, may have the potential to control influenza virus (H5N1) infection.

Phytochemicals from fern species: potential for medicine applications

Ferns are an important phytogenetic bridge between lower and higher plants. Historically they have been used in many ways by humans, including as ornamental plants, domestic utensils, foods, and in handicrafts. In addition, they have found uses as medicinal herbs. Ferns produce a wide array of secondary metabolites endowed with different bioactivities that could potentially be useful in the treatment of many diseases. However, there is currently relatively little information in the literature on the phytochemicals present in ferns and their pharmacological applications, and the most recent review of the literature on the occurrence, chemotaxonomy and physiological activity of fern secondary metabolites was published over 20 years ago, by Soeder (Bot Rev 51:442-536, 1985). Here, we provide an updated review of this field, covering recent findings concerning the bioactive phytochemicals and pharmacology of fern species.

Acute oral toxicity and genotoxicity of Dryopteris crassirhizoma

ETHNOPHARMACOLOGICAL RELEVANCE

Dryopteris crassirhizoma has been traditionally used for the treatment of tapeworm infestation, the common cold and cancer in Korea, China and Japan. Despite various pharmacological properties of Dryopteris crassirhizoma, there is no available information about the safety of Dryopteris crassirhizoma.

AIM OF THIS STUDY

To ensure more information about the safety of Dryopteris crassirhizoma, we performed the acute oral toxicity and genotoxicity tests of Dryopteris crassirhizoma.

MATERIALS AND METHODS

The acute oral toxicity test of Dryopteris crassirhizoma was performed in rats. Genotoxicity of Dryopteris crassirhizoma was evaluated by bacterial reverse mutation, chromosomal aberration and bone marrow micronucleus tests.

RESULTS

In acute toxicity test, Dryopteris crassirhizoma exhibited no mortality, body weight and behavioral changes and adverse effects in male and female rats. Dryopteris crassirhizoma did not significantly increase the number of the bacterial revertant and chromosomal aberration in both in vitro assays. Moreover, the Dryopteris crassirhizoma-related increases of micronucleated polychromatic erythrocytes (MNPCE) in mouse bone marrow were not observed.

CONCLUSION

Therefore, Dryopteris crassirhizoma is non-genotoxic in a three standard battery of tests and the oral LD50 of Dryopteris crassirhizoma is >2000 mg/kg.

Water Extract of Dryopteris crassirhizoma Attenuates Bone Loss by Suppressing Osteoclast Differentiation and Function

The rhizome of Dryopteris crassirhizoma has been used as a traditional herbal medicine for treating various inflammatory and infectious diseases such as tapeworm infestation and mumps. In the present study, we investigated the bone protective effect of water extract of the rhizome of Dryopteris crassirhizoma (WEDC). We found that WEDC inhibits osteoclast differentiation via directly acting on osteoclast precursors. In osteoclast precursors, WEDC inhibited receptor activator of nuclear factor-κB ligand- (RANKL-) induced expression of c-Fos and nuclear factor of activated T cells cytoplasmic 1, a key downstream target of c-Fos during osteoclast differentiation. We found that WEDC inhibits RNAKL-induced activation of extracellular-regulated kinase and NF-κB that mediates c-Fos expression and osteoclast differentiation. In addition to the inhibitory effect of osteoclast differentiation, WEDC markedly suppressed bon-resorbing activity of mature osteoclasts, which was accompanied by disruption of actin ring structure. Furthermore, administration of WEDC suppressed RANKL-induced trabecular bone loss in mice. Collectively, our results demonstrate that WEDC inhibits not only osteoclast differentiation by inhibiting RANK signaling pathways in osteoclast precursors but also bone resorption by disrupting actin ring in mature osteoclasts, thereby contributing to its protective effect on bone loss.

Discovery and antitumor activities of constituents from Cyrtomium fortumei (J.) Smith rhizomes

Background

Cyrtomium fortumei (J.) Smith is an important Chinese herbal medicine because of its biological functions. However, systematic and comprehensive studies on the phytochemicals from Cyrtomium fortumei (J.) Smith and their bioactivity are limited.

Results

Using the bioassay-guided technique, the ethyl acetate and n-BuOH extracts of the rhizomes of Cyrtomium fortumei (J.) Smith were shown to exhibit good antitumor activities, consequently leading to the isolation of 23 compounds. All compounds were isolated from the plant for the first time. The inhibitory activities of these compounds were investigated on tumor cells MGC-803, PC3, and A375 in vitro by MTT (thiazolyl blue tetrazolium bromide) assay, and the results showed that pimpinellin (3) had potent cytotoxic activities against the three cell lines, with the IC₅₀ values of 14.4 ± 0.3 μM, 20.4 ± 0.5 μM, and 29.2 ± 0.6 μM, respectively. The mechanism of the antitumor action indicated that pimpinellin inhibited the growth of MGC-803 cells via the induction of tumor cell apoptosis, with apoptosis ratio of 27.44% after 72 h of treatment at 20 μM.

Conclusions

This study suggests that most of the compounds from the roots of Cyrtomium fortumei (J.) Smith could inhibit the growth of human carcinoma cells. Moreover, pimpinellin inhibited the growth of tumor cells via the induction of tumor cell apoptosis.

Spectaflavoside A, a new potent iron chelating dimeric flavonol glycoside from the rhizomes of Zingiber spectabile Griff

The rhizomes of Zingiber spectabile yielded a new dimeric flavonol glycoside for which the name kaempferol-3-O-(4″-O-acetyl)-α-L-rhamnopyranoside-(I-6,II-8)-kaempferol-3-O-(4″-O-acetyl)-α-L-rhamnopyranoside; spectaflavoside A (1) was proposed, along with kaempferol and its four acetylrhamnosides (2-6), demethoxycurcumin (7) and curcumin (8). The structure of spectaflavoside A was elucidated by spectroscopic methods including, 1D and 2D NMR techniques. This is the first report on the occurrence of a dimeric flavonol glycoside in the Zingiberaceae and the second in nature. Spectaflavoside A was found to be a potent iron chelating agent.

Antibacterial activity of two phloroglucinols, flavaspidic acids AB and PB, from Dryopteris crassirhizoma

The antimicrobial effect of solvent extracts from the rhizome of a thick-stemmed wood fern (Dryopteris crassirhizoma) was evaluated and its phloroglucinol components, flavaspidic acids PB and AB. Flavaspidic acids PB and AB were isolated from the D. crassirhizoma rhizomes by methanol extraction, followed by silica gel and Sephadex LH-20 column chromatography. The chemical structures were characterized by spectral techniques, including ESI-MS, UV, ¹H- and ¹³C-NMR spectrum analysis. When the antimicrobial activity of the extracts and compounds was tested by the paper disc method, the extracts and compounds were highly active against Gram-positive bacteria, such as methicillin-resistant Staphylococcus aureus KCTC 1928 (a MRSA bacterium), Streptococcus mutans and Bacillus subtilis. The extracts and compounds were not active against fungi and chlorella. Our study revealed that the antibacterial activity of samples from D. crassirhizoma was mainly related to the flavaspidic acids.

Two new triterpenes from the Rhizome of Dryopteris crassirhizoma, and inhibitory activities of its constituents on human immunodeficiency virus-1 protease

Two new hopane type triterpenes, named dryopteric acids A (1) and B (2), were isolated from the Rhizome of Dryopteris crassirhizoma (Aspiadaceae) together with sixteen known compounds (3-18). Of isolated compounds, ursolic acid (15), and dryopteric acid A (1) and B (2) showed potent inhibitory activities against HIV-1 protease with IC50 values of 8.9-44.5 microM. In addition, acetylated compounds 1 and 2 appreciably increased inhibitory activities with their IC50 values of 1.7 and 10.8 microM, respectively.

Antibacterial effect of Dryopteris crassirhizoma against methicillin-resistant Staphylococcus aureus

Methanol extract and its fractions (hexane, EtOAc, n-BuOH, and H2O) of Dryopteris crassirhizoma were investigated for antibacterial activity against methicillin-resistant Staphylococcus aureus. The hexane fraction showed a good antibacterial activity against all tested strains.

Potentials of phenolic molecules of natural origin and their derivatives as anti-HIV agents

Identification of phenolic compounds and their derivatives interfering the several steps of the viral life cycle of the human immunodeficiency virus type 1 (HIV-1) is focused for the development of novel molecules for the treatment of AIDS. Several phenolic compounds isolated and characterized from natural sources have been studied in detail and found to exhibit inhibitory effects against different steps of the HIV-1 life cycle, including virus-cell fusion and virus absorption, reverse transcription, integration (IN) and proteolytic cleavage. In the review, we are summarizing some strong evidences demonstrating several phenolic molecules and their derivatives from natural sources display promising anti-HIV-1 activities. The anti-HIV compounds have been organized in this review according to their mechanism of action in the life cycle of HIV. We also mentioned some findings using in silico approaches, like virtual screening, docking, neural network, etc., and even the chemogenomics and/or functional genomics approaches could be useful for the quick identifying promising new lead anti-HIV molecules without having any other unwanted pharmacological effects. Plants having large amount of phenolic compounds, can be considered as strong sources of molecules for the treatment of HIV-1. Despite the continuous advances made in antiretroviral combination therapy, AIDS has become the leading cause of death in Africa and the fourth worldwide. Today, many research groups are exploring the bio- and chemo-diversity of the plant kingdom to find new and better anti-HIV drugs with novel mechanisms of action.

Simple criterion for selection of flavonoid compounds with anti-HIV activity

Flavonoid compounds represent an important natural source of antiretrovirals for AIDS therapy due to their significant anti-HIV-1 activity and low toxicity. Here we propose a simple theoretical criterion to discriminate active from inactive flavonoids that is suitable for rapid in silico screening of flavonoid libraries, and selection and optimization of lead compounds with anti-HIV-1 activity.

Fatty acid synthase inhibitory activity of acylphloroglucinols isolated from Dryopteris crassirhizoma

Fatty acid synthase (FAS) is emerging as a potential therapeutic target to treat cancer and obesity. Bioassay-guided fractionation of a MeOH extract of the rhizomes of Dryopteris crassirhizoma (Dryopteridaceae), using an in vitro FAS inhibitory assay, resulted in the isolation of a series of acylphloroglucinols, as the active principles. The isolates 1-10 inhibited FAS with IC50 values ranging from 23.1+/-1.4 to 71.7+/-3.9 microM. The results of the present study indicate that the acylphloroglucinol derivatives could be considered to be a promising class of FAS inhibitors.

Phenolic constituents from the rhizomes of Dryopteris crassirhizoma

A new phenolic glycoside, dryopteroside (1), was isolated from the rhizomes of Dryopteris crassirhizoma (Dryopteridaceae), together with five known compounds, 4beta-carboxymethyl-(-)-epicatechin (2), isobiflorin (3), biflorin (4), 1-beta-D-glucopyranosyloxy-3-methoxy-5-hydroxybenzene (5) and (+)-catechin-6-C-beta-D-glucopyranoside (6). The new compound was elucidated to be 1-butanoyl-3-C-beta-D-glucopyranosyl-5-methyl-phloroglucinyl-6-O-beta-D-glucopyranoside (1) by chemical and various spectroscopic analyses. The known compounds 2-6 were first reported from the genus Dryopteris.

Three acetylated flavonol glycosides from Forsteronia refracta that specifically inhibit p90 RSK

A survey of plant extracts for the presence of p90 ribosomal S6 kinase (RSK) inhibitors resulted in the isolation of three acetylated flavonol glycosides. Kaempferol 3-O-(2'',4''-O-diacetyl-alpha-l-rhamnopyranoside) (1), kaempferol 3-O-(3'',4''-O-diacetyl-alpha-l-rhamnopyranoside) (2), and kaempferol-3-O-(4''-O-acetyl-alpha-l-rhamnopyranoside) (3) were isolated from Forsteronia refracta as the first RSK inhibitors. Of these, compound 2 was found to be the best inhibitor with an IC(50) value of 89 nM.

Characterisation of polyphenols by HPLC-PAD-ESI/MS and antioxidant activity in Equisetum telmateia

The antioxidant activity of an aqueous extract (infusion) and respective ethyl acetate fraction of Equisetum telmateia Ehrh. (Equisetaceae), a plant used in traditional medicine for its anti-inflammatory and diuretic properties, has been evaluated by DPPH, TEAC and TBARS assays. A high and significant antioxidant activity was detected in the ethyl acetate fraction. Analysis of the aqueous extract and the ethyl acetate fraction by HPLC-PAD-ESI/MS allowed the identification of the major phenolic compounds as flavan-3-ol, kaempferol and phenolic acid derivatives. Among the flavan-3-ols, A-type proanthocyanidins and afzelechin derivatives were detected as well as the more common B-type procyanidins, B2 and C1, whose identification was further confirmed by HPLC using detection involving chemical reaction with p-dimethylamino-cinnamaldehyde. The results suggest that the anti-inflammatory activity of E. telmateia could be due, at least in part, to the presence of compounds with antioxidant activity.

Stilbenes from the roots of Pleuropterus ciliinervis and their antioxidant activities

Two stilbene glycosides, pieceid-2"-O-gallate and pieceid-2"-O-coumarate, were isolated from the MeOH extract of the roots of Pleuropterus ciliinervis Nakai (Polygonaceae), together with two known compounds, resveratrol and pieceid. Their structures were determined spectroscopically, particularly by 2D NMR spectroscopic analysis. The antioxidant activities of stilbenes isolated were determined in vitro against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, superoxide radicals and by determining their lipid peroxidation inhibitory activities. Among the compounds isolated, pieceid-2"-O-gallate had the most potent inhibitory scavenging effect on DPPH, superoxide radicals and upon lipid peroxidation inhibition with IC50 values of 16.5, 23.9 and 5.1 microM, respectively.

Antioxidant activity of two phloroglucinol derivatives from Dryopteris crassirhizoma

The rhizome of Dryopteris crassirhizoma NAKAI exhibited significant antioxidant activity, as assessed by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity in vitro. Two phloroglucinol derivatives, flavaspidic acids PB (1) and AB (2), were isolated from the rhizome of D. crassirhizoma by a bioassay-guided fractionation. 1H-, 13C-NMR, and UV analysis were used to determine the structures. Furthermore, the two compounds were tested for their antioxidant activities, such as their DPPH radical scavenging, superoxide radical scavenging, and lipid peroxidation (LPO) inhibitory activities. Compounds 1 and 2 exhibited potent antioxidant activity against the LPO inhibitory test with IC(50) values of 12.9 and 13.1 microM, respectively, compared with alpha-tocopherol (IC(50); 15.6 microM) and butylated hydroxy anisole (BHA, IC(50); 10.8 microM), while the two compounds had a moderated effect on the DPPH radical scavenging activity (IC(50); 71.7, 76.3 microM) as well as superoxide radical scavenging activity (IC(50); 58.6, 64.4 microM). The potent activity of the flavaspidic acids (1, 2) on inhibiting LPO might be due to possible stabilization as a result of chelating with iron.