Isorhamnetin glycosides with free radical and ONOO− scavenging activities from the stamens ofNelumbo nucifera

Recent advances on bioactive compounds, biosynthesis mechanism, and physiological functions of Nelumbo nucifera

Nelumbo nucifera Gaertn, commonly known as lotus, is a genus comprising perennial and rhizomatous aquatic plants, found throughout Asia and Australia. This review aimed to cover the biosynthesis of flavonoids, alkaloids, and lipids in plants and their types in different parts of lotus. This review also examined the physiological functions of bioactive compounds in lotus and the extracts from different organs of the lotus plant. The structures and identities of flavonoids, alkaloids, and lipids in different parts of lotus as well as their biosynthesis were illustrated and updated. In the traditional medicine systems and previous scientific studies, bioactive compounds and the extracts of lotus have been applied for treating inflammation, cancer, liver disease, Alzheimer's disease, etc. We suggest future studies to be focused on standardization of the extract of lotus, and their pharmacological mechanisms as drugs or functional foods. This review is important for the lotus-based food processing and application.

Structures, Sources, Identification/Quantification Methods, Health Benefits, Bioaccessibility, and Products of Isorhamnetin Glycosides as Phytonutrients

In recent years, people have tended to consume phytonutrients and nutrients in their daily diets. Isorhamnetin glycosides (IGs) are an essential class of flavonoids derived from dietary and medicinal plants such as Opuntia ficus-indica, Hippophae rhamnoides, and Ginkgo biloba. This review summarizes the structures, sources, quantitative and qualitative analysis technologies, health benefits, bioaccessibility, and marketed products of IGs. Routine and innovative assay methods, such as IR, TLC, NMR, UV, MS, HPLC, UPLC, and HSCCC, have been widely used for the characterization and quantification of IGs. All of the therapeutic effects of IGs discovered to date are collected and discussed in this study, with an emphasis on the relevant mechanisms of their health-promoting effects. IGs exhibit diverse biological activities against cancer, diabetes, hepatic diseases, obesity, and thrombosis. They exert therapeutic effects through multiple networks of underlying molecular signaling pathways. Owing to these benefits, IGs could be utilized to make foods and functional foods. IGs exhibit higher bioaccessibility and plasma concentrations and longer average residence time in blood than aglycones. Overall, IGs as phytonutrients are very promising and have excellent application potential.

Profiling of Secondary Metabolites of Optimized Ripe Ajwa Date Pulp (Phoenix dactylifera L.) Using Response Surface Methodology and Artificial Neural Network

The date palm (Phoenix dactylifera L.) is a popular edible fruit consumed all over the world and thought to cure several chronic diseases and afflictions. The profiling of the secondary metabolites of optimized ripe Ajwa date pulp (RADP) extracts is scarce. The aim of this study was to optimize the heat extraction (HE) of ripe Ajwa date pulp using response surface methodology (RSM) and artificial neural network (ANN) modeling to increase its polyphenolic content and antioxidant activity. A central composite design was used to optimize HE to achieve the maximum polyphenolic compounds and antioxidant activity of target responses as a function of ethanol concentration, extraction time, and extraction temperature. From RSM estimates, 75.00% ethanol and 3.7 h (extraction time), and 67 °C (extraction temperature) were the optimum conditions for generating total phenolic content (4.49 ± 1.02 mgGAE/g), total flavonoid content (3.31 ± 0.65 mgCAE/g), 2,2-diphenyl-1-picrylhydrazyl (11.10 ± 0.78 % of inhibition), and cupric-reducing antioxidant capacity (1.43 µM ascorbic acid equivalent). The good performance of the ANN was validated using statistical metrics. Seventy-one secondary metabolites, including thirteen new bioactive chemicals (hebitol II, 1,2-di-(syringoyl)-hexoside, naringin dihydrochalcone, erythron-guaiacylglycerol-β-syringaresinol ether hexoside, erythron-1-(4'-O-hexoside-3,5-dimethoxyphenyl)-2-syrngaresinoxyl-propane-1,3-diol, 2-deoxy-2,3-dehydro-N-acetyl-neuraminic acid, linustatin and 1-deoxynojirimycin galactoside), were detected using high-resolution mass spectroscopy. The results revealed a significant concentration of phytoconstituents, making it an excellent contender for the pharmaceutical and food industries.

Metabolic Profiling and Antioxidant Analysis for the Juvenile Red Fading Leaves of Sweetpotato

Leaves of sweetpotato (Ipomoea batatas L.) are promising healthy leafy vegetable. Juvenile red fading (JRF) leaves of sweetpotato, with anthocyanins in young leaves, are good candidates for developing functional vegetables. Here, metabolic profiling and possible antioxidants were analyzed for five leaf stages of the sweetpotato cultivar "Chuanshan Zi". The contents of anthocyanins, total phenolics, and flavonoids all declined during leaf maturation, corresponding to declining antioxidant activities. By widely targeted metabolomics, we characterized 449 metabolites belonging to 23 classes. A total of 193 secondary metabolites were identified, including 82 simple phenols, 85 flavonoids, 18 alkaloids, and eight terpenes. Analysis of the metabolic data indicates that the antioxidant capacity of sweetpotato leaves is the combined result of anthocyanins and many other colorless compounds. Increased levels of "chlorogenic acid methyl ester", a compromised form of chlorogenic acid, significantly correlated with the declined antioxidant abilities. Besides anthocyanins, some significant metabolites contributing to the high antioxidant property of the sweetpotato leaves were highlighted, including chlorogenic acids, isorhamnetin glycosides, trans-4-hydroxycinnamic acid methyl ester, 4-methoxycinnamic acid, esculetin, caffeate, and trigonelline. This study provides metabolic data for the utilization of sweetpotato leaves as food sources, and sheds light on the metabolomic change for JRF leaves of other plants.

Establishment of Holistic Quality Control Methods for Nelumbinis Folium Containing Alkaloids and Flavonoids with Simple HPLC Conditions

In this study, a positive charged C18 column was used to explore its performance in analysis of herbal medicines containing alkaloids and flavonoids with Nelumbinis Folium (NF) as an example. A chromatographic fingerprint analysis method was established by high performance liquid chromatography-diode array detector with commonly used 0.1% formic acid as mobile phase additive and this method could simultaneously detect both alkaloids and flavonoids with good peak shape. It is noted that the HPLC conditions were directly applied in the HPLC-ESI-Orbitrap-MS/MS analysis, and 12 common peaks were identified. In the quantification method of nuciferine, compared with common C18 column, good performance was observed, including sharp and symmetric peak shape of nuciferine, and no obvious retention time shift in chromatogram. The fingerprint method and quantification method of nuciferine and quercetin-3-O-glucuronic acid could be readily utilized as quality control methods for NF and its related preparations.

Identification and quantification of flavonoids in 207 cultivated lotus (Nelumbo nucifera) and their contribution to different colors

Sacred lotus (Nelumbo nucifera) is a large economic crop, which is also cultivated as a horticultural crop. This study performed a systematic qualitative and quantitative determination of five anthocyanins and 18 non-anthocyanin flavonoids from the petals of 207 lotus cultivars. Among the compounds identified in this study, quercetin 3-O-pentose-glucuronide, quercetin 7-O-glucoside, laricitrin 3-O-hexose, and laricitrin 3-O-glucuronide were discovered for the first time in sacred lotus. The relationships between these pigments and petals colors were also evaluated. A decrease in the total content of anthocyanins and increase in the content of myricetin 3-O-glucuronide resulted in a lighter flower color. Furthermore, petals were yellow when the content of quercetin 3-O-neohesperidoside and myricetin 3-O-glucuronide were increased, whereas petals were red when the total anthocyanin content was high and the quercetin 3-O-sambubioside content was low. These investigations contribute to the understanding of mechanisms that underlie the development of flower color and provide a solid theoretical basis for the further study of sacred lotus.

Isolation of New Constituents from Whole Plant of Salsola imbricata Forssk. of Saudi Origin

This work describes the first report of the known glycosidic constituents β-sitosterol-3-O-β-d-glucoside-6'-palmitate (1), β-sitosterol-3-O-β-d-glucoside (2), momor-cerebroside I (3), phytolacca cerebroside (4), 1,2-di-O-palmitoyl-3-O-(6-sulfoquinovopyranosyl)-glycerol (5), isorhamnetin-3-robinobioside (6), and isorhamnetin-3-rutinoside (7) from the plant Salsola imbricata Forssk. grown in the eastern region of Saudi Arabia. The structures of the isolated compounds were elucidated from extensive 1D and 2D nuclear magnetic resonance (NMR), gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), and chemical analyses. Compound 1 is reported for the first time from the Amaranthaceae family. In addition to the isolated and identified fatty alcohols, compounds 3, 4, 5, and 6 are also reported for the first time from the genus Salsola. The findings of this study suggest a contribution of the isolated compounds to the various biological activities reported for this plant.

Analysis of Gliricidia sepium Leaves by MALDI Mass Spectrometry Imaging

When investigating the potential use of plants as a raw material for an all-natural cosmetic formulation, the main parameters are the chemical composition, antioxidant potential, antimicrobial action, and toxicity. Additionally, the production of natural cosmetics should also consider the availability of primary materials and the environmental and socioeconomic impact. Gliricidia sepium is a species that produces a large amount of plant material, being cultivated in the agroforestry system. However, studies of phytochemical composition and chemical spatial distribution are scarcely using the MALDI MS (matrix-assisted laser desorption ionization mass spectrometry) and MALDI MSI (mass spectrometry imaging) techniques. A methodology was developed to optimize ionization parameters and analysis conditions by evaluating the efficiency of three matrices: α-cyano-4-hydroxycinnamic acid, 2,5-dihydroxybenzoic acid (DHB), and 2-mercaptobenzothiazole in MALDI MS analysis. All results were compared to ESI MS (electrospray ionization mass spectrometry), and afterward, MALDI MSI analysis was performed on the leaf surface. This study showed through phytochemical analysis that G. sepium leaves are composed of polyphenols and tannins, concluding that the methanolic extract had a higher amount of flavonoid content. Four compounds were identified on the leaf surface, and their spatial distribution was analyzed by MALDI MS using DHB as a matrix. Kaempferol, isorhamnetin, and some fatty acids showed potential applicability for cosmetical use. All the extracts presented antioxidant activity or antimicrobial action and no cytotoxicity. Therefore, extracts of G. sepium could be used as raw materials in cosmetics.

Antioxidant and anticancer potentials of edible flowers: where do we stand?

Edible flowers are attracting special therapeutic attention and their administration is on the rise. Edible flowers play pivotal modulatory roles on oxidative stress and related interconnected apoptotic/inflammatory pathways toward the treatment of cancer. In this review, we highlighted the phytochemical content and therapeutic applications of edible flowers, as well as their modulatory potential on the oxidative stress pathways and apoptotic/inflammatory mediators, resulting in anticancer effects. Edible flowers are promising sources of phytochemicals (e.g., phenolic compounds, carotenoids, terpenoids) with several therapeutic effects. They possess anti-inflammatory, anti-diabetic, anti-microbial, anti-depressant, anxiolytic, anti-obesity, cardioprotective, and neuroprotective effects. Edible flowers potentially modulate oxidative stress by targeting erythroid nuclear transcription factor-2/extracellular signal-regulated kinase/mitogen-activated protein kinase (Nrf2/ERK/MAPK), reactive oxygen species (ROS), nitric oxide (NO), malondialdehyde (MDA) and antioxidant response elements (AREs). As the interconnected pathways to oxidative stress, inflammatory mediators, including tumor necrosis factor (TNF)-α, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), interleukins (ILs) as well as apoptotic pathways such as Bcl-2-associated X protein (Bax), Bcl-2, caspase and cytochrome C are critical targets of edible flowers in combating cancer. In this regard, edible flowers could play promising anticancer effects by targeting oxidative stress and downstream dysregulated pathways.

The Effect of Sacred Lotus (Nelumbo nucifera) and Its Mixtures on Phenolic Profiles, Antioxidant Activities, and Inhibitions of the Key Enzymes Relevant to Alzheimer's Disease

Sacred lotus (Nelumbo nucifera) has long been used as a food source and ingredient for traditional herbal remedies. Plant parts contain neuroprotective agents that interact with specific targets to inhibit Alzheimer's disease (AD). Organic solvents including methanol, ethyl acetate, hexane, and n-butanol, are widely employed for extraction of sacred lotus but impact food safety. Seed embryo, flower stalk, stamen, old leaf, petal, and leaf stalk of sacred lotus were extracted using hot water (aqueous extraction). The extractions were analyzed for their bioactive constituents, antioxidant and anti-AD properties as key enzyme inhibitory activities toward acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and β-secretase 1 (BACE-1). Results showed that the sacred lotus stamen exhibited significant amounts of phenolics, including phenolic acids and flavonoids, that contributed to high antioxidant activity via both single electron transfer (SET) and hydrogen atom transfer (HAT) mechanisms, with anti-AChE, anti-BChE, and anti-BACE-1 activities. To enhance utilization of other sacred lotus parts, a combination of stamen, old leaf and petal as the three sacred lotus plant components with the highest phenolic contents, antioxidant activities, and enzyme inhibitory properties was analyzed. Antagonist interaction was observed, possibly from flavonoids-flavonoids interaction. Further in-depth elucidation of this issue is required. Findings demonstrated that an aqueous extract of the stamen has potential for application as a functional food to mitigate the onset of Alzheimer's disease.

Antimelanogenic and Antimigration Properties of the Ethyl Acetate Fraction of Calendula officinalis Flowers on Melanoma Cells

Calendula officinalis L., commonly known as marigold, is not only cultivated for ornamental purposes but is also used as a traditional medicinal herb. Its flowers have been used to treat various skin diseases, including rashes, burns, cuts and bruises, since ancient times. However, to our knowledge, the impact of C. officinalis L. on melanoma and its mechanism have not been clarified. The aim of this work was to investigate the chemical characterization and antimelanogenic and antimigration activities of the ethyl acetate fraction of C. officinalis flowers (EFC), as well as elucidate the potential mechanism. The obtained results showed that EFC markedly decreased α-MSH-induced melanin production and the cell migration ability of melanoma cells in a dose-dependent manner. Additionally, EFC significantly inhibited the activity and expression of matrix metalloproteinase 2 (MMP-2) via suppressing the mitogen-activated protein kinase (MAPK) signaling pathway. Taken together, the present study demonstrated that C. officinalis flowers can be used as a natural source of antimelanogenisis and antimigration regent to treatment or prevent skin diseases.

Lotus Flavonoids and Phenolic Acids: Health Promotion and Safe Consumption Dosages

Nelumbo nucifera Gaertn., also known as the sacred lotus, is extensively cultivated in Southeast Asia, primarily for food and as an herbal medicine. This article reviews studies published between 1995 and 2017, on flavonoid and phenolic acid profiles and contents of 154 different cultivars of lotus. So far, some 12 phenolic acids and 89 to 90 flavonoids (47 flavonols, 25 to 26 flavons, 8 flavan-3-ols, 4 flavanons, and 5 anthocyanins) have been isolated from different parts of the lotus plant, including its leaves (whole leaf, leaf pulp, leaf vein, and leaf stalk), seeds (seedpod, epicarp, coat, kernel, and embryo), and flowers (stamen, petal, pistil, and stalk), although not all of them have been quantified. Factors affecting flavonoids and phenolic acid profiles, including types of tissues and extracting factors, are discussed in this review, in order to maximize the application of the lotus and its polyphenols in the food industry. Health promotion activities, attributed to the presence of flavonoids and phenolic acids, are described along with toxicology studies, illustrating appropriate usage and safe consumption dosages of lotus extracts. This review also presents the controversies and discusses the research gaps that limit our ability to obtain a thorough understanding of the bioactivities of lotus extracts.

Nelumbo nucifera Gaertn leaves extract inhibits the angiogenesis and metastasis of breast cancer cells by downregulation connective tissue growth factor (CTGF) mediated PI3K/AKT/ERK signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Nelumbo nucifera Gaertn (Nymphaeaceae) has been recognized as a medicinal plant, which was distributed throughout the Asia. The aqueous extract of Nelumbo nucifera leaves extract (NLE) has various biologically active components such as polyphenols, flavonoids, oligomeric procyanidines. However, the role of NLE in breast cancer therapy is poorly understood.

THE AIM OF THIS STUDY

The purpose of this study was to identify the hypothesis that NLE can suppress tumor angiogenesis and metastasis through CTGF (connective tissue growth factor), which has been implicated in tumor angiogenesis and progression in breast cancer MDA-MB-231 cells.

RESULTS

We examined the effects of NLE on angiogenesis in the chicken chorioallantoic membrane (CAM) model. The data showed that NLE could reduce the chorionic plexus at day 17 in CAM and the duration of this inhibition was dose-dependent. In Xenograft model, NLE treatment significantly reduced tumor weight and CD31 (capillary density) over control, respectively. We examined the role of angiogenesis involved restructuring of endothelium using human umbilical vein endothelial cell (HUVEC) in Matrigel angiogenesis model. The results indicated that vascular-like structure formation was further blocked by NLE treatment. Moreover, knockdown of CTGF expression markedly reduced the expression of MMP2 as well as VEGF, and attenuated PI3K-AKT-ERK activation, indication that these signaling pathways are crucial in mediating CTGF function.

CONCLUSION

The present results suggest that NLE might be useful for treatment in therapy-resistance triple negative breast cancer.

Contribution to the characterization of Opuntia spp. juices by LC-DAD-ESI-MS/MS

Opuntia spp. fruits are considered as health promoting foods due to the diversity of bioactive molecules found in these fruits. The composition in organic acids, flavonols and betalains in the Opuntia ficus-indica juice from a region of Portugal was accomplished for the first time by liquid chromatography and tandem mass spectrometry using an electrospray ionization source operating in negative and positive mode. The methodology used allowed the detection of 44 compounds, from which 32 were identified. Isorhamnetin derivatives were the dominant flavonol glycosides. A total of 9 betalains including 6 betaxanthins and 3 betacyanin were also detected in the fruit juice samples and indicaxanthin, betanin and isobetanin were the major pigments. Phenolic acid and phenylpyruvic acid derivatives were also identified. To our knowledge, it is the first time derivative compounds from piscidic acid, phenolic compounds and betalains are characterized in cactus pear juice using a single LC-DAD-ESI-MS/MS method.

Antioxidant and anti-inflammatory activity of a flavonoid-rich concentrate recovered from Opuntia ficus-indica juice

A flavonoid-rich concentrate (FRC) recovered from cactus pear juice is able to modulate intestinal oxidative stress biomarkers and inflammatory mediators suggesting that it could be an interesting natural ingredient to attenuate and prevent intestinal chronic inflammation.

Acute and subchronic oral toxicity studies of Nelumbo nucifera stamens extract in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Since the use of Nelumbo nucifera stamens in herbal medicines as well as in cosmetic products are highly prevalent in Thailand and increasing worldwide, acute and subchronic toxicity studies to confirm the safe use of Nelumbo nucifera stamens are warranted.

AIM OF THE STUDY

Acute and subchronic oral toxicity studies of Nelumbo nucifera stamens extract in rats were performed in the present study in order to evaluate its safety.

MATERIALS AND METHODS

In acute toxicity study, Nelumbo nucifera stamens extract was administered by oral gavage to Sprague-Dawley rats (5 males and 5 females) at a dose of 5000 mg/kg. In subchronic toxicity study, the extract at doses of 50, 100, and 200mg/kg/day were given orally to groups of rats (6 rats/dose/sex) for 90 consecutive days.

RESULTS

The extract at a dose of 5000 mg/kg produced no treatment-related signs of toxicity or mortality in any of the animals tested during 14 days of the study. In the repeated dose 90-day oral toxicity study, there was no significant difference in body weight between the control and all treatment groups with the exception of the body weight of the female group treated with 200mg/kg/day of the extract which was statistically significantly less than that of its control counterpart on day 90 but the percent weight changes of both groups were almost similar. Some statistically significant differences in hematological and biochemical parameters as well as in some internal organ weights of both male and female rats treated with the extract at the highest dose were observed. However, no abnormality of internal organs was observed in both gross and histopathological examinations.

CONCLUSIONS

These results suggest that the oral lethal dose of Nelumbo nucifera stamens extract for male and female rats is in excess of 5000 mg/kg and the no-observed-adverse-effect level (NOAEL) of the extract for both male and female rats is considered to be 200mg/kg/day.

Tomato ( Lycopersicon esculentum ) seeds: new flavonols and cytotoxic effect

In this study, seeds of Lycopersicon esculentum Mill. were analyzed by HPLC/UV-PAD/MS(n)-ESI. Fourteen flavonoids were identified, including quercetin, kaempferol, and isorhamnetin derivatives, with 13 of them being reported for the first time in tomato seeds. The major identified compounds were quercetin-3-O-sophoroside, kaempferol-3-O-sophoroside, and isorhamnetin-3-O-sophoroside. A significant cell proliferation inhibition (>80%), against rat basophile leukemia (RBL-2H3) cell line, was observed with this extract (IC(50) = 5980 microg/mL). For acetylcholinesterase inhibitory activity, a concentration-dependent effect was verified (IC(20) = 2400 microg/mL). The same behavior was noted regarding antioxidant capacity, evaluated against DPPH (IC(10) = 284 microg/mL), nitric oxide (IC(25) = 396 microg/L), and superoxide radicals (IC(25) = 3 microg/mL).

The sacred lotus (Nelumbo nucifera)– phytochemical and therapeutic profile

Objectives

Nelumbo nucifera Gaertn. (Nymphaeaceae), also known as sacred lotus, is a well known medicinal plant. This article reviews the traditional uses, phytochemistry and therapeutic reports on different parts of N. nucifera viz. the seeds, rhizomes, leaves and flowers. This review also describes various compounds isolated from different parts of this plant and the therapeutic benefits derived from those phytoconstituents.

Key findings

There are several therapeutic benefits of this plant for which different parts are used. The extracts of rhizomes, seeds, flowers and leaves have been reported to have varied therapeutic potential. Several bioactive compounds have been derived from these plant parts belonging to different chemical groups, including alkaloids, flavonoids, glycosides, triterpenoid, vitamins etc., which all have their own therapeutic impact. Thus, the pharmacological effects and various active ingredients of different parts of N. nucifera are well understood.

Summary

In this review we explore the current pharmaceutical, phytochemical and pharmacological knowledge about this well known plant species as well as several emerging aspects for research on N. nucifera.

Isorhamnetin protects rat ventricular myocytes from ischemia and reperfusion injury

Ischemia/reperfusion (I/R) has been known to cause damages to ventricular myocytes. Isorhamnetin, one member of flavonoid compounds, has cardioprotective effect, the effect that suggests a possible treatment for I/R damages. In the present investigation, we found that isorhamnetin could significantly promote the viability of neonatal rat ventricular myocytes that were exposed to ischemia/reperfusion (I/R) in vitro. Ventricular myocytes were obtained from neonatal SD rats, and then were divided randomly into three groups, namely I/R-/isor-, I/R+/isor- and I/R+/isor+ group. Before the whole experiment, the most appropriate concentration of isorhamnetin (4 μM) was determined by MTT assay. Our results showed that isorhamnetin could alleviate the damages of I/R to ventricular myocytes through inhibiting lactate dehydrogenase (LDH) activity, and repressing apoptosis. Compared with the counterpart of the I/R+/isor- group, LDH activity in the isorhamnetin-treated group weakened, halving from 24.1 ± 2.3 to 11.4 ± 1.2U/L. Additionally, flow cytometry showed the apparently increased apoptosis rate induced by I/R, the result that was further confirmed by transmission electron microscope. Administration of isorhamnetin, however, assuaged the apoptosis induced by I/R. Corresponding to the reduced apoptosis rate in the I/R+/isor+ group, western blotting assay showed increased amount of Bcl-2 and p53, decreased amount of Bax, and nuclear accumulation of NF-κB/p65.

Simultaneous determination of quercetin and its glycosides from the leaves of Nelumbo nucifera by reversed-phase high-performance liquid chromatography

The purpose of this study was to develop reversed-phase HPLC method for the simultaneous determination of the flavonoids from the leaves of Nelumbo nucifera, which have been known to exhibit antioxidant, anti-HIV, antihyperlipidemic and antiobesity effects. HPLC separation was achieved on C(18) column using gradient elution with mobile phase consisting of acetonitrile-water containing 0.1% formic acid. The separated peaks were identified by electrospray ionization mass spectrometry. The HPLC method was validated and applied for the simultaneous determination of the bioactive flavonoids from the leaves of Nelumbo nucifera. In the methanol extract, six flavonoids, quercetin, rutin, quercetin 3-O-beta-D-galactopyranoside (Qc-3-Gal), quercetin 3-O-beta-D-glucopyranoside (Qc-3-Glc), quercetin 3-O-beta-D-glucuronide (Qc-3-Gln) and quercetin 3-O-alpha-arabinopyranosyl-(1-->2)-beta-galactopyranoside (Qc-3-AraGal), were identified. Among them, Qc-3-Glc and Qc-3-Gln were found to be major component in the methanol extract of Nelumbo nucifera leaves.

New phenolic compounds and antioxidant potential of Catharanthus roseus

Screening of the phenolic compounds from seeds, stems, leaves and petals of Catharanthus roseus (L.) G. Don (cv. Little Bright Eye) was achieved by HPLC-DAD-ESI-MS/MS. This is the first detailed study of noncolored phenolics in C. roseus, which allowed the characterization of three caffeoylquinic acids and fifteen flavonol glycosides (di- and trisaccharides of kaempferol, quercetin and isorhamnetin). Fifteen compounds are reported for the first time in this species. The scavenging ability of the different plant matrices was assessed against DPPH(*) radical and against reactive oxygen (superoxide radical) and a reactive nitrogen (nitric oxide) species. A concentration-dependent protective effect was observed for seeds and tissues, with petals shown to be the most active.

In vitro activity of almond skin polyphenols for scavenging free radicals and inducing quinone reductase

Observational studies and clinical trials suggest nut intake, including almonds, is associated with an enhancement in antioxidant defense and a reduction in the risk of cancer and cardiovascular disease. Almond skins are rich in polyphenols (ASP) that may contribute to these putative benefits. To assess their potential mechanisms of action, we tested the in vitro effect of ASP extracted with methanol (M) or a gastrointestinal juice mimic (GI) alone or in combination with vitamins C (VC) or E (VE) (1-10 micromol/L) on scavenging free radicals and inducing quinone reductase (QR). Flavonoid profiles from ASP-M and -GI extracts were different from one another. ASP-GI was more potent in scavenging HOCl and ONOO (-) radicals than ASP-M. In contrast, ASP-M increased and ASP-GI decreased QR activity in Hepa1c1c7 cells. Adding VC or VE to ASP produced a combination- and dose-dependent action on radical scavenging and QR induction. In comparison to their independent actions, ASP-M plus VC were less potent in scavenging DPPH, HOCl, ONOO (-), and O 2 (-) (*). However, the interaction between ASP-GI plus VC promoted their radical scavenging activity. Combining ASP-M plus VC resulted in a synergistic interaction, inducing QR activity, but ASP-GI plus VC had an antagonistic effect. On the basis of their total phenolic content, the measures of total antioxidant activity of ASP-M and -GI were comparable. Thus, in vitro, ASP act as antioxidants and induce QR activity, but these actions are dependent upon their dose, method of extraction, and interaction with antioxidant vitamins.

The flavonoid component isorhamnetin in vitro inhibits proliferation and induces apoptosis in Eca-109 cells

Isorhamnetin is one member of flavonoid components which has been used in the treatment of heart disease. Recently the in vitro anti-cancer effect of isorhamnetin on human esophageal squamous carcinoma cell line Eca-109 was investigated in our lab. When Eca-109 cells were in vitro exposed to the graded doses of isorhamnetin (0-80 microg/ml) for 48 h, respectively, isorhamnetin exhibited cytostatic effect on the treated cells, with an IC(50) of 40+/-0.08 microg/ml as estimated by MTT assay. Inhibition on proliferation by isorhamnetin was detected by trypan blue exclusion assay, clone formation test, immunocytochemical assay of PCNA and (3)H-thymidine uptake analysis. Cell cycle distribution was measured by FCM. It was found that the viability of Eca-109 cells was significantly hampered by isorhamnetin. Compared with the negative control group, the treated group which was exposed to isorhamnetin had increased population in G(0)/G(1) phase from 74.6 to 84 while had a significant reduction in G(2)/M phase from 11.9 to 5.8. In addition to its cytostatic effect, isorhamnetin also showed stimulatory effect on apoptosis. Typical apoptotic morphology such as condensation and fragmentation of nuclei and blebbing membrane of the apoptotic cells could be observed through transmission electron microscope. Moreover, the sharp increase in apoptosis rate between the control and treated group were detected by FCM from 6.3 to 16.3. To explore the possible molecular mechanisms that underlie the growth inhibition and apoptosis stimulatory effects of isorhamnetin, the expressions of six proliferation- and death-related genes were detected by FCM. Expressions of bcl-2, c-myc and H-ras were downregulated whereas Bax, c-fos and p53 were upregulated. However, the in vivo experiments were required to further confirm the anti-cancer effects of isorhamnetin. In conclusion, isorhamnetin appears to be a potent drug against esophageal cancer due to its in vitro potential to not only inhibit proliferation but also induce apoptosis of Eca-109 cells.