The phenols and prodelphinidins of white clover flowers

Unveiling myricetin's pharmacological potency: A comprehensive exploration of the molecular pathways with special focus on PI3K/AKT and Nrf2 signaling

Myricetin can be found in the traditional Chinese medicinal plant, Myrica rubra. Myricetin is a flavonoid that is present in many vegetables, fruits, and plants and is considered to have strong antioxidant properties as well as a wide range of therapeutic applications. Growing interest has been piqued by its classification as a polyphenolic molecule because of its potential therapeutic benefits in both the prevention and management of numerous medical conditions. To clarify myricetin's traditional medical uses, modern research has investigated various pharmacological effects such as antioxidant, anticancer, anti-inflammation, antiviral, antidiabetic, immunomodulation, and antineurodegenerative effects. Myricetin shows promise as a nutritional flavonol that could be beneficial in the prevention and mitigation of prevalent health conditions like diabetes, cognitive decline, and various types of cancer in humans. The findings included in this study indicate that myricetin has a great deal of promise for application in the formulation of medicinal products and nutritional supplements since it affects several enzyme activities and alters inflammatory markers. However, comprehensive preclinical studies and research studies are necessary to lay the groundwork for assessing myricetin's possible effectiveness in treating these long-term ailments. This review summarizes both in vivo and in vitro studies investigating myricetin's possible interactions through the nuclear factor-E2-related factor 2 (Nrf2) as well as PI3K (phosphatidylinositol 3-kinase)/AKT (protein kinase B) signaling pathways in an attempt to clarify the compound's possible clinical applicability across a range of disorders.

Arginase inhibitory activities of chemical constituents from Macaranga hurifolia Beille leaves

The methanolic extract of the leaves of Macaranga hurifolia Beille showed arginase inhibitory activity (40% at 100 µg/mL) and was then fractionated to obtain nine polyphenolic compounds. Their structures were elucidated on the basis of NMR spectroscopic data, and by comparison with data previously reported in the literature, as gallic acid (1), 3,4-dihydroxybenzoic acid (2), chlorogenic acid, (3), corilagin (4), cynaroside (5), cosmosiin (6), hyperoside (7) isoquercitrin (8) and guajaverin (9). These compounds have been evaluated as arginase inhibitors. Compounds 4, 7, 8 and 9 showed varying arginase inhibitory activities with IC50 values ranging from 102 to 302 μM. All the isolated compounds were previously identified in this species but their activities on arginase are reported here for the first time.

Undescribed Phenolic Glycosides from Syzygium attopeuense and Their Inhibition of Nitric Oxide Production

Four undescribed phenolic glycosides including three stilbene derivatives (1 and 3) and sodium salt of 3 (2), and a chalcone glycoside (4), together with thirteen known compounds (5-17) were isolated from the leaves of Syzygium attopeuense (Gagnep.) Merr. & L.M.Perry. Their chemical structures were elucidated to be (Z)-gaylussacin (1), 6''-O-galloylgaylussacin sodium salt (2), 6''-O-galloylgaylussacin (3), 4'-O-[β-D-glucopyranosyl-(1→6)-glucopyranosyl]oxy-2'-hydroxy-6'-methoxydihydrochalcone (4), gaylussacin (5), pinosilvin 3-O-β-D-glucopyranoside (6), myricetin-3-O-(2''-O-galloyl)-α-L-rhamnopyranoside (7), myricetin-3-O-(3''-O-galloyl)-α-L-rhamnopyranoside (8), myricetin-3-O-α-L-rhamnopyranoside (9), quercitrin (10), myricetin-3-O-β-D-glucopyranoside (11), myricetin-3-O-β-D-galactopyranoside (12), quercetin 3-O-α-L-arabinopyranoside (13), myricetin-3-O-2''-O-galloyl)-α-L-arabinopyranoside (14), (+)-gallocatechin (15), (-)-epigallocatechin (16), and 3,3',4'-trimethoxyellagic acid 4-O-β-D-glucopyranoside (17) by the analysis of HR-ESI-MS, 1D and 2D NMR spectra in comparison with the previously reported data. Compounds 1-3, 5, and 6 significant inhibition of NO production in LPS-activated RAW264.7 cells, with IC50 values ranging from 18.37±1.38 to 35.12±2.53 μM, compared to a positive control (dexamethasone) with an IC50 value of 15.37±1.42 μM.

R2R3-MYB gene family: Genome-wide identification provides insight to improve the content of proanthocyanidins in Trifolium repens

The R2R3-MYB family is one of largest transcription factor families in plants playing significant roles in regulating anthocyanin and proanthocyanidin biosynthesis. Proanthocyanidins are one of major objectives to improve the quality of white clover (Trifolium repens L.), which have a beneficial effect on ruminant to prevent the lethal pasture bloat. A total of 133 TrR2R3-MYB genes were identified and distributed on all 16 chromosomes based on the whole genome information of white clover. Also, by exploring the gene structure, motifs and duplication events of TrR2R3-MYBs, as well as the evolutionary relationship with TrR2R3-MYB genes of other species, 10 TrR2R3-MYB genes with the potential to regulate the anthocyanins and proanthocyanidins biosynthesis were screened. These TrR2R3-MYB genes responded significantly to low temperature in white clover. In addition, they have different expression patterns in leaves, petioles and inflorescences of white clover. Importantly, TrMYB116 and TrMYB118 may positively regulate anthocyanin accumulation and low temperature response in white clover. TrMYB118 may also be associated with anthocyanin pigmentation pattern in Purple leaves. This study provides a basis for verifying the function of TrR2R3-MYB and breeding white clover cultivars with high proanthocyanidins.

Myricetin: a Multifunctional Flavonol in Biomedicine

PURPOSE OF REVEIW

The root cause of many diseases like CVD, cancer, and aging is free radicals which exert their effect by interfering with different metabolic pathways. The sources of free radicals can be exogenous, like UV rays from sunlight, and endogenous due to different metabolic by-products.In our body, there are defense mechanisms present, such as antioxidant enzymes and antioxidant molecules to combat these free radicals, but if there is an overload of these free radicals in our body, the defense system may not be sufficient to neutralize these free radicals. In such situations, we are exposed to a chronic low dose of oxidants creating oxidative stress, which is responsible for eliciting different diseases.

RECENT FINDINGS

Pubmed and Google Scholar are the search engines used to sort out relevant papers on myricetin and its role in combating many diseases. Myricetin is present in many fruits and vegetables and is a known antioxidant. It can elevate the antioxidant enzyme levels; reduces the lipid peroxidation; and is known to protect against cancer. In the case of myocardial dysfunction, myricetin has been shown to suppress the inflammatory cytokines and reduced the mortality rate. Myricetin has also been found to reduce platelet aggregation and control the viral infections by interfering in the DNA replication pathways.

SUMMARY

In this paper, we have briefly reviewed about the different type and site of free radicals and the role of myricetin in addressing the ROS and different diseases.

Antioxidant Phenylpropanoid Glycosides from Ginkgo biloba Fruit and Identification of a New Phenylpropanoid Glycoside, Ginkgopanoside

Ginkgo biloba (Ginkgoaceae), well-known as the oldest living plant species and often referred to as a "living fossil," is a famous medicinal plant that has been used in multiple countries to improve numerous illnesses, including anxiety, dementia, peripheral artery disease, and eye problems. We conducted a phytochemical exploration of G. biloba fruit, commonly consumed as a functional food as part of an ongoing natural product chemical research for the discovery of bioactive phytochemicals with novel structures. The natural product chemical analysis of the methanol extract of G. biloba fruit using column chromatography and high-performance liquid chromatography separation under the guidance of a liquid chromatography-mass spectrometry (LC/MS)-based analysis identified six phenylpropanoid glycosides (1-6), including one new compound, ginkgopanoside (1). The structures of the isolated compounds were elucidated by nuclear magnetic resonance spectroscopic data and LC/MS analysis, and the absolute configuration of compound 1 was established by chemical reactions followed by the application of Snatzke's method. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities of the isolated compounds 1-6 and the aglycone 1a of 1 were evaluated, and we found that compounds 1-5 exhibited antioxidant activities with IC₅₀ values in the range 32.75-48.20 μM, while the aglycone 1a exhibited greater radical scavenging activity (IC₅₀ = 5.23 μM) comparable to that of ascorbic acid (IC₅₀ = 2.54 μM), a positive control, implying that the present of glucose may decrease the DPPH scavenging activity. These findings provide experimental information that the active phenylpropanoid glycosides could represent natural antioxidants for use in pharmaceuticals and functional foods.

Penicacids H-J, three new mycophenolic acid derivatives from the marine-derived fungus Rhizopus oryzae

Chemical investigation of secondary metabolites in crude methanol extract of a solid rice medium of a marine-derived fungus, Rhizopus oryzae, has enriched the metabolic profile of this genus by affording three mycophenolic acid derivatives recognized as new fungal metabolites trivially named as penicacids H–J (1–3), along with two known naphtho-γ-pyrone dimers, asperpyrone A (4) and dianhydroaurasperone C (5). Structure elucidation of isolated compounds was unambiguously determined based on extensive 1D and 2D NMR spectroscopic analyses together with comparing coupling constant and optical rotation values with those reported for related congeners in literature. All isolated compounds were assessed for their antibacterial activity against four different bacterial microorganisms and they revealed moderate to weak activities with minimum inhibitory concentration (MIC) values ranging from 62.5 to 250 μg mL⁻¹.

Penicacids H–J (1–3), three new natural MPA derivatives, were purified from a marine-derived fungus, Rhizopus oryzae, together with two known naphtho-γ-pyrone dimers, asperpyrone A (4) and dianhydroaurasperone C (5).

A new prenylated coumestan from the roots of Campylotropis hirtella

A new prenylated coumestan, campylohirtin A (1), along with fifteen phenolic known compounds (2‒16) and four other known compounds (17‒20), was obtained from the 95% ethanol extract of roots of Campylotropis hirtella. Their structures were elucidated based on extensive spectroscopic analysis (1 D and 2 D-NMR, MS, UV and IR). In vitro antimalarial activities of compounds 1-3, 5-14 and 16 were evaluated by β-hematin formation inhibition assay. Compared with the positive control chloroquine diphosphate, compounds 8, 11 and 16 exhibited strong antimalarial activity with the IC₅₀ values of 69.9, 33.2 and 75.4 µM, respectively. Compounds 1-3, 5-7 and 12 showed moderate antimalarial activities with IC₅₀ values ranging from 134.6 µM to 578.6 µM.[Formula: see text].

Compounds Isolated from Wikstroemia taiwanensis Regulate Bone Remodeling by Modulating Osteoblast and Osteoclast Activities

Bone remodeling, a dynamic process in which bone formation by osteoblast is preceded by bone resorption by osteoclast, is a vital physiological process for maintaining bone mass and strength, imbalances in which could precipitate osteoporosis. Due to the unilateral mechanism of the existing bone remodeling drugs, identifying compounds that could regulate the balance between osteoclast and osteoblast could improve the treatment of osteoporosis. Here, we show that compounds isolated from Wikstroemia taiwanensis modulate osteoclast and osteoblast activities. Specifically, astragalin (1) and kaempferol 3-O-β-D-apiofuranosyl-(1→6)-β-D-glucopyranoside (2), besides increasing mineral deposition, increased alkaline phosphatase activity (137.2% for 1 and 115.8% for 2) and ESR-α expression (112.8% for 1 and 122.5% for 2) in primary human osteoblasts. In contrast, compounds 1, 2, 3, and 5 inhibited tartrate-resistant acid phosphatase (TRAP) activity in receptor activator of nuclear factor-κB ligand-induced osteoclasts by 40.8, 17.1, 25.9, and 14.5% and also decreased the number of TRAP-positive cells by 51.6, 26.8, 20.5, and 18.6%, respectively. Our findings, therefore, showed that compounds isolated from W. taiwanensis could increase osteoblast activity while simultaneously decreasing osteoclast activity, and hence, warrant further evaluation for development as anti-osteoporosis agents.

Assessing the Potential of Diverse Forage Mixtures to Reduce Enteric Methane Emissions In Vitro

Methane emissions from ruminants are a major contributor to agricultural greenhouse gas emissions. Thus, eight different forage species were combined in binary mixtures with Lolium perenne in increasing proportions, in vitro, to determine their methane reduction potential in ruminants. Species were sampled in two consecutive years where possible. The aims were: a) to determine if mixtures with specific forages, particularly those rich in plant specialized metabolites (PSM), can reduce methane emissions compared to ryegrass monocultures, b) to identify whether there is a linear-dose effect relationship in methane emissions from the legume or herb addition, and c) whether these effects are maintained across sampling years. Results showed that all dicot species studied, including the non-tannin-containing species, reduced methane production. The tannin-rich species, Sanguisorba minor and Lotus pedunculatus, showed the greatest methane reduction potential of up to 33%. Due to concomitant reductions in the forage digestibility, Cichorium intybus yielded the lowest methane emissions per digestible forage unit. Contrary to total gas production, methane production was less predictable, with a tendency for the lowest methane production being obtained with a 67.5% share of the legume or herb partner species. Thus, linear increments in the partner species share did not result in linear changes in methane concentration. The methane reduction potential differed across sampling years, but the species ranking in methane concentration was stable.

Responses of Lotus corniculatus to environmental change 3: The sensitivity of phenolic accumulation to growth temperature and light intensity and effects on tissue digestibility

Growth temperature and light intensity are major drivers of phenolic accumulation in Lotus corniculatus resulting in major changes in carbon partitioning which significantly affects tissue digestibility and forage quality. The response of plant growth, phenolic accumulation and tissue digestibility to light and temperature was determined in clonal plants of three genotypes of Lotus corniculatus (birdsfoot trefoil) cv Leo, with low, intermediate or high levels of proanthocyanidins (condensed tannins). Plants were grown from 10 °C to 30 °C, or at light intensities from 20 to 500 µm m^-2 s^-1. Plants grown at 25 °C had the highest growth rate and highest digestibility, whereas the maximum tannin concentration was found in plants grown at 15 °C. Approximately linear increases in leaf flavonol glycoside levels were found with increasing growth temperature in the low tannin genotype. Tannin hydroxylation increased with increasing growth temperature but decreased with increasing light intensity. The major leaf flavonols were kaempferol glycosides of which kaempferol-3-glucoside and kaempferol-3,7-dirhamnoside were the major components. Increases in both tannin and total flavonol concentrations in leaves were linearly related to light intensity and were preceded by a specific increase in the transcript level of a non-legume type chalcone isomerase. Changes in growth temperature and light intensity, therefore, result in major changes in the partitioning of carbon into phenolics, which significantly affects tissue digestibility and nutritional quality with a high correlation between tannin concentration and leaf digestibility.

Antioxidant and α-Glucosidase Inhibitory Activities Guided Isolation and Identification of Components from Mango Seed Kernel

In the present study, petroleum ether, dichloromethane, ethyl acetate, and n-butanol fractions of mango seed kernel exhibited different degrees of antioxidant and α-glucosidase inhibitory activity. Thus, quantitative and qualitative analysis of the petroleum ether fraction was conducted by GC-MS. Among identified components, four unsaturated fatty acids had never been reported in natural products before, together with 19 known components. In addition, 17 compounds were isolated and elucidated from other active fractions. Compounds 2, 9, 15, and 17 were isolated for the first time from Mangifera genus. Compounds 1 and 2 exhibited prominent DPPH radical scavenging and α-glucosidase inhibitory effects. In order to further explore their mechanism of α-glucosidase inhibition, their enzyme kinetics and in silico modeling experiments were performed. The results indicated that 1 inhibited α-glucosidase in a noncompetitive manner, whereas 2 acted in a competitive manner. In molecular docking, the stability of binding was enhanced by π-π T-shaped, π-alkyl, π-π stacked, hydrogen bond, and electrostatic interactions. Thus, compounds 1 and 2 were determined to be new potent antioxidant and α-glucosidase inhibitors for preventing food oxidation and enhancing hypoglycemic activity.

Nephroprotective property of Trifolium repens leaf extract against paracetamol-induced kidney damage in mice

Paracetamol-induced toxicity is one of the major drawbacks in the treatment of inflammatory conditions. The present study was performed to find out the impacts of phenolic compounds in the Trifolium repens (white clover) leaves (TR) against the paracetamol-induced nephrotoxicity in mice. The extract was administered orally to mice in different doses (1, 2, and 3 mL having a dry mass of 11.0 mg/mL) along with paracetamol (300 mg/kg) alone or in combination. Kidney histology, serum renal function tests, serum electrolytes, reduced glutathione, and lipid peroxidation were evaluated. Paracetamol significantly affected kidney weight, renal profile biochemistry, serum electrolytes, reduced glutathione, and thiobarbituric acid reactive substances (as lipid peroxidation) in mice. The amount of total phenolic compounds identified in the extract was 8.89 mg/g, representing 80.8% of the extract. The simultaneous administration of the TR extract leads to the normalization of all those parameters, which were deviated due to paracetamol ingestion. Kidney histological examination showed that nephrotoxicity was induced due to paracetamol, while the extract rich in phenolic compounds acts as therapeutic agents. The administration of extract also normalized the reduced glutathione from 0.837 to 2.21 of the paracetamol and paracetamol with 3-mL extract, respectively. Lipid peroxidation in the kidney was significantly (p < 0.05) declined by the extract (0.435 µmol/g) as compared to PC (3.96 µmol/g). In conclusion, TR extract possesses active beneficial phenolic compounds with nephroprotective function.

Phytochemical profile and pharmacological properties of Trifolium repens

Trifolium repens belongs to the family Leguminosae and has been used for therapeutic purposes as traditional medicine. The plant is widely used as fodder and leafy vegetables for human uses. However, there is a lack of a detailed review of its phytochemical profile and pharmacological properties. This review presents a comprehensive overview of the phytochemical profile and biological properties of T. repens. The plant is used as antioxidants and cholinesterase inhibitors and for anti-inflammatory, antiseptic, analgesic, antirheumatic ache, and antimicrobial purposes. This review has summarized the available updated useful information about the different bioactive compounds such as simple phenols, phenolic acids, flavones, flavonols, isoflavones, pterocarpans, cyanogenic glucosides, saponins, and condensed tannins present in T. repens. The pharmacological roles of these secondary metabolites present in T. repens have been presented. It has been revealed that T. repens contain important phytochemicals, which is the potential source of health-beneficial bioactive components for food and nutraceuticals industries.

Characterization of antioxidant, α-glucosidase and tyrosinase inhibitors from the rhizomes of Potentilla anserina L. and their structure-activity relationship

Five new flavonoids (1-5), along with 25 known compounds, were isolated from the rhizomes of Potentilla anserina L. and their structures were identified using spectroscopic and chemical evidence. The extract, all fractions, and all isolated compounds were evaluated for their antioxidant, α-glucosidase, and tyrosinase inhibitory activities, and their structure-activity relationship was interpreted. The biflavanols and quercetin-3-O-α-l-rhamnopyranoside-2″-gallate (14) exhibited significant antioxidant and α-glucosidase inhibition activities. In this study, anti-tyrosinase activity and its mechanism of active compounds (potenserin C (4), potenserin D (5), and quercetin-3-O-α-l-rhamnopyranoside-2″-gallate (14)) were explored by a combination of computational simulations and kinetic studies. Kinetic studies indicated that potenserin C (4) and quercetin-3-O-α-l-rhamnopyranoside-2″-gallate (14) inhibited tyrosinase in a competitive manner, whereas potenserin D (5) acted in a reversible noncompetitive manner. The molecular docking result indicated that the substitution of the glucose moiety with galloyl and the presence of 3', 4', 5'-OH in flavonoid aglycones played a crucial role for the tyrosinase inhibiting effect. Moreover, the presence of biflavanols increased the activity against tyrosinase because of strong hydrogen binding, π-alkyl binding, and electrostatic interaction. Thus, the presented experiments developed several new lead compounds that could act as antioxidants and α-glucosidase inhibitors. Furthermore, biflavanols and quercetin-3-O-α-l-rhamnopyranoside-2″-gallate played important roles in the anti-browning activity during food processing.

Milk production, nitrogen utilization, and methane emissions of dairy cows grazing grass, forb, and legume-based pastures

Achieving high animal productivity without degrading the environment is the primary target in pasture-based dairy farming. This study investigated the effects of changing the forage base in spring from grass-clover pastures to forb or legume-based pastures on milk yield, N utilization, and methane emissions of Jersey cows in Western Oregon. Twenty-seven mid-lactation dairy cows were randomly assigned to one of three pasture treatments: grass-clover-based pasture composed of festulolium, tall fescue, orchardgrass, and white clover (Grass); forb-based pasture composed of chicory, plantain, and white clover (Forb); and legume-based pasture composed of red clover, bird's-foot trefoil, berseem clover, and balansa clover (Legume). Pastures were arranged in a randomized complete block design with three replicates (i.e., blocks) with each replicate grazed by a group of three cows. Production and nutritive quality of the forages, animal performance, milk components, nitrogen partitioning, and methane emissions were measured. Feed quality and dry matter intake (DMI) of cows were greater (P ≤ 0.05) for Legume and Forb vs. Grass, with consequent greater milk and milk solids yields (P < 0.01). Cows grazing Forb also had more (P < 0.01) lactose and linoleic acid in milk compared with cows grazing the other pastures, and less (P = 0.04) somatic cell counts compared with Grass. Cows grazing Forb had substantially less (P < 0.01) N in urine, milk, and blood compared with cows grazing the other pastures, with not only a greater (P < 0.01) efficiency of N utilization for milk synthesis calculated using milk urea nitrogen but also a larger (P < 0.01) fecal N content, indicating a shift of N from urine to feces. Both Forb and Legume had a diuretic effect on cows, as indicated by the lower (P < 0.01) creatinine concentration in urine compared with Grass. Methane emissions tended to be less (P = 0.07) in cows grazed on Forb vs. the other pastures. The results indicate that Forb pasture can support animal performance, milk quality, and health comparable to Legume pasture; however, Forb pasture provides the additional benefit of reduced environmental impact of pasture-based dairy production.

Elevation of Condensed Tannins in the Leaves of Ta-MYB14-1 White Clover (Trifolium repens L.) Outcrossed with High Anthocyanin Lines

Condensed tannins (CT) are highly desirable in forage as they sequester dietary protein and reduce bloat and methane emissions in ruminants. However, the widely used forage legume white clover (Trifolium repens) only produces CTs in flowers and trichomes and at levels too low to achieve therapeutic effects. Genetic transformation with transcription factor Ta-MYB14-1 from Trifolium arvense was effective in inducing CTs to 0.6% of leaf dry matter. CT synthesis has been elevated further by crossing the primary white clover transgenic line with wild type genotypes producing the related phenylpropanoids, anthocyanins. CT levels in leaves were highest under the anthocyanin leaf marks associated with the "red midrib" trait; however, there was no evidence for CT accumulation in leaf sections with the "red V" anthocyanin marking. Ta-MYB14-1 was stably inherited in two generations of crosses, and T2 progeny produced up to 3.6-fold higher CTs than the T0 parent. The profile of small CT oligomers such as dimers and trimers was consistent in T0, T1, T2, and BC2 progeny and consisted predominantly of prodelphinidins (PD), with lesser amounts of procyanidins (PC) and mixed PC:PD oligomers.

Structural characterization and anti-inflammatory activity evaluation of chemical constituents in the extract of Trifolium repens L

The chemical constituents in Trifolium repens L. were comprehensively studied by UPLC in this work, and a total number of 308 compounds were detected with 169 ones identified. The possible fragmentation pathways were proposed and fragmentation rules were summarized. On the basis of the concluded strategies, the characterized compounds could be classified into organic acids and their derivatives, alkaloids, amino acids, peptides, flavonoids, oligosaccharides, coumarins, and other types of compounds. This approach provided a rapid way for the identification of constituents in T. repens L., and even in other complex analytes. Among the separation and identification of the constituents, three compounds of great amount were isolated and characterized by NMR. The expression of iNOS and COX-2 in LPS-induced RAW 264.7 cells was suppressed by the pretreatment with three isolated constituents. The results implied they may potentially serve as a remedy for the therapy of inflammation. PRACTICAL APPLICATIONS: This work provided a rapid method for the identification of the complex analyte, which could be used in TCM, natural food and so on. The summarized fragmentation rule could be applied for the analysis of several types of compounds, such as organic acids and their derivatives, alkaloids, amino acids and peptides, flavonoids, oligosaccharides, coumarins, and so on. Most of natural plants contain these kinds of compounds, so these rules could have wide applications. Except the phytochemical investigation, T. repens L. displayed anti-inflammation activity according to the reported literature, and the three isolated constituents may potentially serve as a remedy for the therapy of inflammation referring to the result of this research.

New Depsides and Neuroactive Phenolic Glucosides from the Flower Buds of Rugosa Rose ( Rosa rugosa)

The flower buds of Rosa rugosa Thunb. have been commonly used as a source of rose oil and as an ingredient in tea in eastern Asia, including China, Japan, and Korea. Repeated chromatography of a hot water extract from the flower buds of R. rugosa led to the isolation and characterization of three new depside glucosides, rosarugosides A-C (1-3), along with three phenolic compounds, one ionone glucoside, four flavonoids, and two tannins having known chemical structures. Linarionoside A and 2-phenylethyl-(6- O-galloyl)-β-d-glucopyranoside were isolated from R. rugosa for the first time in this study. The structures of the new compounds 1-3 were elucidated by interpreting one- and two-dimensional nuclear magnetic resonance spectroscopic and mass spectrometric data. Among the isolates, a new depside glucoside (1) and two major phenolic glucosides (4 and 5) improved MK-801-induced sensorimotor gating deficits, which were measured via an acoustic startle response test in mice.

Effects of phenolic compounds from aqueous extract of Trifolium repens against acetaminophen-induced hepatotoxicity in mice

The aqueous extract of Trifolium repens (TR) leaves was analyzed for the phenolic profile using reversed phase HPLC-DAD and administered to mice against acetaminophen-induced hepatoxicity. Twenty-four phenolic compounds were identified and quantified. The highest amounts present were of kaempferol-3-(caffeoyldiglucoside)-7-glucoside (983.7 µg/ml), followed by p-coumaroyl-4-glucoside (905.6 µg/ml) and daidzein-O-sulfate (808.3 µg/ml). The aqueous extract was administered to mice along with acetaminophen at different doses. Acetaminophen was found to significantly alter body weight, serum biochemistry, and hematological indices of mice, which were ameliorated by the co-administration of aqueous extract. Liver histopathological studies revealed that acetaminophen significantly induced toxicity, while TR aqueous extract provides curative functions. Lipid peroxidation and total reduced glutathione in the liver were also normalized by the aqueous extract of TR. The aqueous extract of TR was rich in important phenolic compounds, which can be used as a source of beneficial bioactive compounds with hepato-protective function. PRACTICAL APPLICATIONS: Acetaminophen has been widely used as antipyretic and analgesic. However, the major complication reported is hepatotoxicity. Synthetic or conventional drugs used for hepatic diseases or against hepatotoxicity are insufficient and causes severe side effects. For this purpose, traditional medicinal plants or nutraceuticals are used to decrease in the side effects of different hepatotoxic medicine are demanding. Food and neutraceuticals are rich in important polyphenolic compounds which are the best antioxidants. This study was aimed to evaluate the phenolic composition of aqueous extract of Trifolium repens and its potential protective action against the acetaminophen-induced toxicity in mice. This study showed for the first time that the aqueous extract of TR was protective against the hepatotoxicity induced by acetaminophen.

Antiproliferative Activity of (-)-Rabdosiin Isolated from Ocimum sanctum L

Background:Ocimum sanctum L. (holy basil; Tulsi in Hindi) is an important medicinal plant, traditionally used in India. Methods: The phytochemical study of the nonpolar (dichloromethane 100%) and polar (methanol:water; 7:3) extracts yielded fourteen compounds. Compounds 6, 7, 9, 11, 12, and 13, along with the methanol:water extract were evaluated for their cytotoxicity against the human cancer cell lines MCF-7, SKBR3, and HCT-116, and normal peripheral blood mononuclear cells (PBMCs). Results: Five terpenoids, namely, ursolic acid (1), oleanolic acid (2), betulinic acid (3), stigmasterol (4), and β-caryophyllene oxide (5); two lignans, i.e., (-)-rabdosiin (6) and shimobashiric acid C (7); three flavonoids, luteolin (8), its 7-O-β-D-glucuronide (9), apigenin 7-O-β-D-glucuronide (10); and four phenolics, (E)-p-coumaroyl 4-O-β-D-glucoside (11), 3-(3,4-dihydroxyphenyl) lactic acid (12), protocatechuic acid (13), and vanillic acid (14) were isolated. Compound 6 was the most cytotoxic against the human cancer lines assessed and showed very low cytotoxicity against PBMCs. Conclusions: Based on these results, the structure of compound 6 shows some promise as a selective anticancer drug scaffold.

Phenolic Content and Antioxidant Activity in Trifolium Germplasm from Different Environments

Phenolics are important mediators in plant-environment interactions. The presence and concentration of phenolic compounds and their antioxidant activity were evaluated in leaves and flowers of a set of Trifolium species originating from contrasting environments encompassing lowland and mountain sites. The current germplasm proved a great reservoir of phenolic compounds, with different chemical structure and, possibly, diversified biological activity. Germplasm groups with specific phenolic composition were observed. In some cases, different patterns bore a taxonomic meaning. Lowland germplasm showed higher concentration of total phenolics in leaves than mountain accessions (50.30 vs. 34.19 mg/g dry matter (DM)), while the latter had higher concentration in flowers (114.16 vs. 57.44 mg/g DM). Outstanding concentration of isoflavones was observed in leaves of lowland germplasm (24.19 mg/g DM), and of both proanthocyanidins and flavonoids in flowers of mountain germplasm (53.81 and 56.62 mg/g DM, respectively). The pattern of phenolic composition in lowland and mountain germplasm was suggestive of different adaptive strategies. Three assays of antioxidant activity were tested, which were characterised by rather different reactivity towards phenolic composition. The scavenging activity was higher for leaf extracts of lowland germplasm, and for flower extracts of mountain germplasm. Besides identifying germplasm of interest, this study also suggested possible links between environmental factors and concentration and composition of phenolic compounds.

C-8 N-Ethyl-2-pyrrolidinone-Substituted Flavan-3-ols from the Leaves of Camellia sinensis var. pubilimba

Camellia sinensis var. pubilimba, one variety of the genus Camellia sect. Thea (Theaceae), has been used for producing green tea mainly by the local people of its growing areas of Guangxi province, China. Forty compounds, including eight C-8 N-ethyl-2-pyrrolidinone-substituted flavan-3-ols (1-8) and their substituted unit N-ethyl-5-hydroxy-2-pyrrolidinone (9), four flavan-3-ol monomers (10-13) and one dimer (14), nine flavonoids (15-23), three hydrolyzable tannins (24-26), two lignans (27-28), 11 simple phenolics (29-39), and caffeine (40), were first isolated and identified from the leaves. Their structures were determined by detailed spectroscopic analysis and comparison with the literature data and authentic samples. Both 1 and 4 were obtained as a mixture of the N-ethyl-2-pyrrolidinone C-5 enantiomers (1a and 1b and 4a and 4b), respectively, while the resolution of another three pairs of enantiomers (2 and 3, 5 and 6, and 7 and 8) was achieved. Among them, 1b is a new compound whose NMR data together with its enantiomer (1a) were reported for the first time, while 2 and 3 are two new natural products. Most of the isolates exhibited significant antioxidant activities, stronger than ascorbic acid and trolox, while parts of the isolates, particularly C-8 N-ethyl-2-pyrrolidinone-substituted flavan-3-ols, showed obvious inhibitory effects on acetylcholinesterase (AChE). The results indicated that C. sinensis var. pubilimba is a valuable plant resource for tea production.

Phytochemical Investigation of the Fern Asplenium ceterach (Aspleniaceae)

The fern Asplenium ceterach L. (syn. Ceterach officinarum Willd.) is used in local traditional medicine against kidney stones, gallstones, to facilitate diuresis and to treat benign prostatic hyperplasia. The aim of this study was first to investigate the chemical composition of this fern and then to study the chemical profile of the herbal preparations used in local medicine due to its diuretic properties. In total, nine secondary metabolites from the methanol extract of the aerial parts have been isolated; three flavonoids, namely kaempherol-3- O- β-D-gentiobioside (1), quercetin-3- O- β-D-glucuronide (2), quercetin-3- O- β-D-gentiobioside (3), three phenolic acids, i.e. caffeic acid (4), chlorogenic acid (5) and p-coumaroyl-4- O- β-D-glucoside (6), as well as three phenols, 4-vinyl-phenol-1- O- β-D-glucopyranoside (7), 3-(1- O- β-D-glucopyranosyl-4-hydroxyphenyl)-propionic acid (8), and 4- β- O-D-glucosyl-3,4-dihydroxybenzyl alcohol (9). Moreover, the cyclohexane residue has been submitted to GC-MS and NMR analyses and revealed the presence of ethyl esters of palmitic, linoleic and α-linolenic acids. Finally, based on NMR, TLC and HPLC analyses, it was evident that the chemical fingerprints of all herbal preparations were quite similar, with chlorogenic acid being the main compound and caffeic acid present only in traces.

A new diacetylated flavonol triglycoside from the aerial parts of Actinidia polygama

Phytochemical investigation of a methanolic extract of aerial parts Actinidia polygama Miq. led to the isolation of one new diacetylated flavonol triglycoside, kaempferol 3-O-[α-L-rhamnopyranosyl(1→3)-(4-O-acetyl)-O-α-L-rhamnopyranosyl(1→6)-(2-Oacetyl)-O-β-D-galactopyranoside] (1) along with 12 known compounds (2-13). The chemical structures were determined using their spectroscopic data including 1D and 2D NMR. To the best of our knowledge, this is the first time that compounds 2, 4, 6, 7, 8, 9, 12 and 13 are isolated from this plant. All purified compounds were tested for free radical scavenging effect using DPPH and ABTS assays. Our results showed that compounds 4, 6, 7 and 13 have potential antioxidative effect for scavenging both DPPH^· and ABTS^·+ radicals that are comparable with those of ascorbic acid used as positive control, whereas compounds 1 and 2, which are di- and mono- acetylated flavonol triglycoside respectively, were not found to be potent scavengers of free radicals.

Detailed Chemical Composition of Condensed Tannins via Quantitative (31)P NMR and HSQC Analyses: Acacia catechu, Schinopsis balansae, and Acacia mearnsii

The chemical composition of Acacia catechu, Schinopsis balansae, and Acacia mearnsii proanthocyanidins has been determined using a novel analytical approach that rests on the concerted use of quantitative (31)P NMR and two-dimensional heteronuclear NMR spectroscopy. This approach has offered significant detailed information regarding the structure and purity of these complex and often elusive proanthocyanidins. More specifically, rings A, B, and C of their flavan-3-ol units show well-defined and resolved absorbance regions in both the quantitative (31)P NMR and HSQC spectra. By integrating each of these regions in the (31)P NMR spectra, it is possible to identify the oxygenation patterns of the flavan-3-ol units. At the same time it is possible to acquire a fingerprint of the proanthocyanidin sample and evaluate its purity via the HSQC information. This analytical approach is suitable for both the purified natural product proanthocyanidins and their commercial analogues. Overall, this effort demonstrates the power of the concerted use of these two NMR techniques for the structural elucidation of natural products containing labile hydroxy protons and a carbon framework that can be traced out via HSQC.

Antioxidant Activity of Phenolic Compounds from Fava Bean Sprouts

Fava beans are eaten all over the world and recently, marketing for their sprouts began in Japan. Fava bean sprouts contain more polyphenols and l-3,4-dihydroxyphenylalanine (l-DOPA) than the bean itself. Our antioxidant screening program has shown that fava bean sprouts also possess a higher antioxidant activity than other commercially available sprouts and mature beans. However, the individual constituents of fava bean sprouts are not entirely known. In the present study, we investigated the phenolic compounds of fava bean sprouts and their antioxidant activity. Air-dried fava bean sprouts were treated with 80% methanol and the extract was partitioned in water with chloroform and ethyl acetate. HPLC analysis had shown that the ethyl acetate-soluble parts contained phenolic compounds, separated by preparative HPLC to yield 5 compounds (1-5). Structural analysis using NMR and MS revealed that the compounds isolated were kaempferol glycosides. All isolated compounds had an α-rhamnose at the C-7 position with different sugars attached at the C-3 position. Compounds 1-5 had β-galactose, β-glucose, α-rhamnose, 6-acetyl-β-galactose and 6-acetyl-β-glucose, respectively, at the C-3 position. The amount of l-DOPA in fava bean sprouts was determined by the quantitative (1) H NMR technique. The l-DOPA content was 550.45 mg ± 11.34 /100 g of the raw sprouts. The antioxidant activities of compounds 2-5 and l-DOPA were evaluated using the 2,2-diphenyl-1-picrylhydrazyl scavenging assay. l-DOPA showed high antioxidant activity, but the isolated kaempferol glycosides showed weak activity. Therefore, it can be suggested that l-DOPA contributed to the antioxidant activity of fava bean sprouts.

Chemical constituents of Solanum coagulans and their antimicrobial activities

The present study aimed at determining the chemical constituents of Solanum coagulans and their antimicrobial activities. The compounds were isolated by various chromatographic techniques and their structures were elucidated on the basis of extensive spectroscopic analysis, chemical methods, and comparison with reported spectroscopic data. One new phenolic glycoside, methyl salicylate 2-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranoside (1), together with 12 known compounds (2-13), were isolated from the aerial parts of Solanum coagulans. Compound 1 was a new phenolic glycoside, and 2-6 were isolated from Solanum genus for the first time. The antimicrobial activities of the isolated compounds were also evaluated. Compound 7 showed remarkable antifungal activity against T. mentagrophytes, M. gypseum and E. floccosum with MIC values being 3.13, 1.56 and 3.13 μg·mL(-1), respectively.

Galloylated proanthocyanidins from shea (Vitellaria paradoxa) meal have potent anthelmintic activity against Ascaris suum

Proanthocyanidins (PA) from shea (Vitellaria paradoxa) meal were investigated by thiolytic degradation with benzyl mercaptan and the reaction products were analysed by high performance liquid chromatography-mass spectrometry. These PA were galloylated (≈40%), contained only B-type linkages and had a high proportion of prodelphinidins (>70%). The mean degree of polymerisation was 8 (i.e. average molecular size was 2384Da) and epigallocatechin gallate (EGCg) was the major flavan-3-ol subunit in PA. Shea meal also proved to be a potentially valuable source for extracting free flavan-3-ol-O-gallates, especially EGCg (575mg/kg meal), which is known for its health and anti-parasitic benefits. Proanthocyanidins were isolated and tested for bioactivity against Ascaris suum, which is an important parasite of pigs. Migration and motility tests revealed that these PA have potent activity against this parasitic nematode.

Gastroprotective effects and antimicrobial activity of Lithraea molleoides and isolated compounds against Helicobacter pylori

ETHNOPHARMACOLOGICAL RELEVANCE

Lithraea molleoides (Vell.) Engl. (Anacardiaceae) is a medicinal plant traditionally used in South America to treat various ailments, including diseases of the digestive system.

AIM OF THE STUDY

To evaluate the in vivo antiulcer and antimicrobial activities against Helicobacter pylori of L. molleoides and its isolated compounds.

MATERIALS AND METHODS

Methanolic extract 250 and 500 mg/kg, (LmE 250 and LmE 500, respectively) and infusions, 10 g and 20 g en 100mL (LmI 10 and LmI 20, respectively) of L. molleoides was evaluated for antiulcer activity against 0.6N HCl, 0.2N NaOH, 200mg/kg acetilsalicilic acid and absolute ethanol-induced gastric ulcers in rats. The degree of erosion in the glandular part of the stomach was assessed from a scoring system. Acute toxicity in mice was also evaluated. The antiulcer effect of the isolated compounds (catechol, mannitol, rutin, gallic acid, ferulic acid and caffeic acid, 100mg/kg) was evaluated against absolute ethanol-induced gastric ulcers in rats. The anti-Helicobacter pylori activity of L. molleoides and isolated compounds was performed using broth dilution methods.

RESULTS

The LmE 250, LmE 500, LmI 10 and LmI 20 produced significant inhibition on the ulcer index in 0.6N HCl, 0.2N NaOH, 200mg/kg acetilsalicilic acid and absolute ethanol- induced gastric ulcers in rats. The isolated compounds, catechol, mannitol, rutin, ferulic acid and caffeic acid were active in absolute ethanol- induced gastric ulcers in rats. L. molleoides and different compounds showed antimicrobial activity in all strains tested. The lowest MIC value (0. 5 μg/mL) was obtained with catechol in six of eleven strains assayed. No signs of toxicity were observed with doses up to 2g/kg in an acute toxicity assay.

CONCLUSION

These findings indicate that L. molleoides displays potential antiulcerogenic and antimicrobial activities and the identification of active principles could support the use of this plant for the treatment of digestive affections.

Senna alata leaves are a good source of propelargonidins

Proanthocyanidins (PA) in Senna alata leaves were investigated by thiolysis with benzyl mercaptan, LC-MS and NMR and consisted of almost pure propelargonidins with <6% procyanidins, had B-type linkages and a mean degree of polymerisation of three. Epiafzelechin was the major flavan-3-ol subunit (>94%) and epicatechin a minor constituent (6.4%) in residual PA and mainly detected as an extension unit.

Lotus japonicus flowers are defended by a cyanogenic β-glucosidase with highly restricted expression to essential reproductive organs

Flowers and leaves of Lotus japonicus contain α-, β-, and γ-hydroxynitrile glucoside (HNG) defense compounds, which are bioactivated by β-glucosidase enzymes (BGDs). The α-HNGs are referred to as cyanogenic glucosides because their hydrolysis upon tissue disruption leads to release of toxic hydrogen cyanide gas, which can deter herbivore feeding. BGD2 and BGD4 are HNG metabolizing BGD enzymes expressed in leaves. Only BGD2 is able to hydrolyse the α-HNGs. Loss of function mutants of BGD2 are acyanogenic in leaves but fully retain cyanogenesis in flowers pointing to the existence of an alternative cyanogenic BGD in flowers. This enzyme, named BGD3, is identified and characterized in this study. Whereas all floral tissues contain α-HNGs, only those tissues in which BGD3 is expressed, the keel and the enclosed reproductive organs, are cyanogenic. Biochemical analysis, active site architecture molecular modelling, and the observation that L. japonicus accessions lacking cyanogenic flowers contain a non-functional BGD3 gene, all support the key role of BGD3 in floral cyanogenesis. The nectar of L. japonicus flowers was also found to contain HNGs and additionally their diglycosides. The observed specialisation in HNG based defence in L. japonicus flowers is discussed in the context of balancing the attraction of pollinators with the protection of reproductive structures against herbivores.

¹H-¹³C HSQC NMR spectroscopy for estimating procyanidin/prodelphinidin and cis/trans-flavan-3-ol ratios of condensed tannin samples: correlation with thiolysis

Studies with a diverse array of 22 purified condensed tannin (CT) samples from nine plant species demonstrated that procyanidin/prodelphinidin (PC/PD) and cis/trans-flavan-3-ol ratios can be appraised by (1)H-(13)C HSQC NMR spectroscopy. The method was developed from samples containing 44-∼100% CT, PC/PD ratios ranging from 0/100 to 99/1, and cis/trans ratios ranging from 58/42 to 95/5 as determined by thiolysis with benzyl mercaptan. Integration of cross-peak contours of H/C-6' signals from PC and of H/C-2',6' signals from PD yielded nuclei-adjusted estimates that were highly correlated with PC/PD ratios obtained by thiolysis (R(2) = 0.99). cis/trans-Flavan-3-ol ratios, obtained by integration of the respective H/C-4 cross-peak contours, were also related to determinations made by thiolysis (R(2) = 0.89). Overall, (1)H-(13)C HSQC NMR spectroscopy appears to be a viable alternative to thiolysis for estimating PC/PD and cis/trans ratios of CT if precautions are taken to avoid integration of cross-peak contours of contaminants.

Immunoregulatory and anti-HIV-1 enzyme activities of antioxidant components from lotus (Nelumbo nucifera Gaertn.) rhizome

In the present study, two antioxidant micromolecular components (L2f-2 and L2f-3) and an antioxidant macromolecular component LB2 were extracted from lotus (Nelumbo nucifera Gaertn.) rhizomes. MS, FTIR (Fourier-transform IR) spectroscopy and NMR were used to identify these compounds. L2f-2 was (+/-)-gallocatechin, L2f-3 was (-)-catechin and LB2 was a polysaccharide-protein complex with a molecular mass of 18.8 kDa. LB2 was identified as a polysaccharide sulfate containing α/β-pyranose and α-furanose according to its FTIR spectrogram. It was composed of mannose, rhamnose, glucose, galactose and xylose with a molar ratio 2:8:7:8:1. The antioxidant components L2f-2, L2f-3 and LB2 strongly inhibited HIV-1 RT (reverse transcriptase) and IN (integrase). LB2 inhibited RT with an IC50 value of 33.7 μM. It also exhibited the highest HIV-1 3'-processing inhibitory activity with an IC50 value of 5.28 μM. Both L2f-2 and L2f-3 up-regulated the expression of IL-2 (interleukin-2) and down-regulated IL-10, while LB2 exhibited positive regulation on IL-2, IL-4 and IL-10. Moreover, L2f-3 and LB2 might inhibit HIV-1 directly by down-regulating TNFα (tumour necrosis factor α). These natural antioxidant components with antiviral and immunoregulatory activities could be potentially important for anti HIV-1 drug development and application to HIV-1 therapy.

Antioxidant Capacity and Proanthocyanidin Composition of the Bark of Metasequoia glyptostroboides

Metasequoia glyptostroboides Hu et Cheng is the only living species in the genus Metasequoia Miki ex Hu et Cheng (Taxodiaceae), which is well known as a “living fossil” species. In the Chinese folk medicine, the leaves and bark of M. glyptostroboides are used as antimicrobic, analgesic, and anti-inflammatory drug for dermatic diseases. This study is the first to report the free radical scavenging capacity, antioxidant activity, and proanthocyanidin composition of the bark of M. glyptostroboides. We observed total of six extracts and fractions, which were easily obtained by water-ethanol extraction and followed by a further separation with D101 resin column chromatography, had significant DPPH radical, superoxide anion radical, and hydroxyl radical scavenging capacity, total antioxidative capacity (T-AOC), lipid peroxidation inhibitory activity, and metal ions chelating capacity. The fraction MGEB, which was obtained by 60% ethanol extraction and followed by a further separation with D101 resin column chromatograph, possessed the highest proanthocyanidin content and the highest free radical scavenging and antioxidant activities. Furthermore, MGEB could significantly protect against CCl₄ induced acute liver injury through inhibition of oxidative stress in mice. In addition, ten proanthocyanidins were isolated from MGEB, and six of them were firstly reported from this plant.

Ultraperformance liquid chromatography tandem mass spectrometry determination of cyanogenic glucosides in Trifolium species

Cyanogenic glucosides were analyzed by ultra-high-performance liquid chromatography combined with mass spectrometry in 88 Trifolium species grown at the same site. On the basis of the occurrence of cyanogenic glucosides and the linamarin/lotaustralin ratio species could be grouped into five clusters. Cluster C1 included 37 species, which did not contain cyanogens. Cluster C2 (22 species) included plants containing only lotaustralin. In clusters C3 (14 species), C4 (13 species), and C5 (2 species) both linamarin and lotaustralin were present but at different ratios. In C3 and C4 the linamarin/lotaustralin ratio was below 1, whereas in cluster C5 the ratio was much higher. Generally, the total content of cyanogens was below 500 μg/g dry matter. Only in Trifolium repens var. biasoletti and Trifolium montanum extremely high cyanogen concentrations were observed. There was no general rule of occurrence of cyanogens. Samples of the same species from different countries accumulated cyanogens or could be free of these compounds.

Characterization of the phytochemical constituents of Taif rose and its antioxidant and anticancer activities

Ward Taifi (Taif rose) is considered one of the most important economic products of Taif, Saudi Arabia. In this study both fresh and dry Taif rose were biologically and phytochemically investigated. The 80% methanol extracts and n-butanol fractions of dry and fresh Taif rose had high radical scavenging activity toward artificial 1,1-diphenyl picrylhydrazyl (DPPH)(•) radical with SC50 values range 5.86-12.24 µg/ml whereas the aqueous fractions showed weak activity. All samples had in vitro anticancer activity toward HepG2 with IC50 < 20 µg/ml which fall within the criteria of the American Cancer Institute. High positive correlation appeared between the antioxidant activity and total phenolics whereas there is no correlation between total phenolics and anticancer activity. The LC-ESI(- ve)-MS analysis of all extracts indicate the presence of phenolic compounds belonging to hydrolysable tannins and flavonol glycosides. In conclusion, the presence of this is considered to be the first phytochemical report that identifies the major compounds in dry and fresh roses using HPLC-ESI-MS. The methanol extracts and its n-butanol and aqueous fractions for both fresh and dry Taif rose could be used as preventive and therapeutic effective natural agents for diseases in which free radicals involved after more in vitro and in vivo studies.

Phytochemical constituents of Sarracenia purpurea L. (pitcher plant)

From the leaves of Sarracenia purpurea, collected in Mistissini, Quebec, Canada, four goodyerosides and three phenolics and nine known compounds, were isolated. The structures of the compounds were determined by mass spectrometry, including HRMS, and by 1D and 2D NMR spectroscopy.

Flavonoids from the cocoon of Rondotia menciana

Two flavonol glycosides along with four known flavonoids were isolated from the cocoon of the mulberry white caterpillar, Rondotia menciana (Lepidoptera: Bombycidae: Bombycinae), a closely related species of the domesticated silkworm Bombyx mori, both of which feed on leaves of mulberry (Morus alba). The two glycosides were characterized as quercetin 3-O-β-d-galactopyranosyl-(1→3)-β-d-galactopyranoside and kaempferol 3-O-β-d-galactopyranosyl-(1→3)-β-d-galactopyranoside, based on spectroscopic data and chemical evidence. The flavonol galactosides found in the cocoon were not present in the host plant, nor in the cocoon of the silkworm, B. mori. Notably, flavonol glucosides, which are the main constituents of cocoon flavonoids in B. mori mori, were not found in the R. menciana cocoon. The present result strongly suggests that R. menciana is quite unique in that they predominantly use an UDP-galactosyltransferase for conjugation of dietary flavonoids, whereas UDP-glucosyltransferases are generally used for conjugation of plant phenolics and xenobiotics in other insects.

Phenolic Content and DPPH Radical Scavenging Activity of the Flowers and Leaves of Trifolium repens

In order to facilitate the quality control of Trifolium repens flowers and leaves, a RP-HPLC method with UV detection was developed for the simultaneous quantitative determination of flavonols and isoflavones. The total flavonoid and phenolic (TPC) contents were determined spectrophotometrically in a visible part of the light spectrum at 425 and 760 nm, respectively. Additionally, evaluation of the antioxidant properties of the plant materials was performed using the DPPH in vitro test. The results showed that the flowers are the richest source of phenolics ranging from 28.7 to 38.8 mg GAE/g, and flavonoids, calculated for hyperoside, up to 20 mg HP/g, which hydrolyzed mainly to flavonols (the quercetin level greater than 6 mg/g). T. repens is poor in isoflavones; similar quantities of ca. 0.2 mg/g were detected in the flowers and leaves. The flower and leaf extracts showed antioxidant activity towards DPPH with EC50 values ranging from 72.3 to 179.3 μg/mL. Significant linear correlations were found between antioxidant potentials of the studied plant materials and total phenolic and flavonoid contents determined by HPLC and spectrophotometric methods ( R2 in the range of 0.97 - 0.99).