Functional characterization of genes related to triterpene and flavonoid biosynthesis in Cyclocarya paliurus.

MAIN CONCLUSION: The oxidosqualene cyclases (OSCs) generating triterpenoid skeletons in Cyclocarya paliurus were identified for the first time, and two uridine diphosphate (UDP)-glycosyltransferases (UGTs) catalyzing the glycosylation of flavonoids were characterized. Cyclocarya paliurus, a native rare dicotyledonous plant in China, contains an abundance of triterpenoid saponins and flavonoid glycosides that exhibit valuable pharmaceutical effects in preventing hypertension, hyperlipidemia, and diabetes. However, the molecular mechanism explaining the biosynthesis of triterpenoid saponin and flavonoid glycoside in C. paliurus remains unclear. In this study, the triterpene content in different tissues and the expression pattern of genes encoding the key enzymes associated with triterpenoid saponin and flavonoid glycoside biosynthesis were studied using transcriptome and metabolome analysis. The eight upstream oxidosqualene cyclases (OSCs) involved in triterpenoid saponin biosynthesis were functionally characterized, among them CpalOSC6 catalyzed 2,3;22,23-dioxidosqualene to form 3-epicabraleadiol; CpalOSC8 cyclized 2,3-oxidosqualene to generate dammarenediol-II; CpalOSC2 and CpalOSC3 produced ß-amyrin and CpalOSC4 produced cycloartenol, while CpalOSC2-CpalOSC5, CpalOSC7, and CpalOSC8 all produced lanosterol. However, no catalytic product was detected for CpalOSC1. Moreover, two downstream flavonoid uridine diphosphate (UDP)-glycosyltransferases (UGTs) (CpalUGT015 and CpalUGT100) that catalyze the last step of flavonoid glycoside biosynthesis were functionally elucidated. These results uncovered the key genes involved in the biosynthesis of triterpenoid saponins and flavonoid glycosides in C. paliurus that could be applied to produce flavonoid glycosides and key triterpenoid saponins in the future via a synthetic strategy.

Chemical Constituents of the Fruits of Cornus Officinalis and Evaluation of their Neuroprotective Activity.

The phytochemical investigation of the fruits of Cornus officinalis yielded a new phenolic acid derivative, neophenolic acid A (1), and a novel flavonoid glycoside, (2R)-naringenin-7-O-ß-(6''-galloyl-glucopyranoside) (2 a), along with six known flavonoid glycosides (2 b-7). Their structures were determined by 1D, 2D NMR and HRESIMS data. The absolute configuration of 1 was established by ECD analysis. Compounds 1- 7 were evaluated for their neuroprotective activities against corticosterone (CORT)-induced injury in PC-12 cells. Compounds 1, 2 a, 2 b, 5, and 6 exhibited neuroprotective activities against CORT-induced neurotoxicity in PC-12 cells. The underlying mechanism study suggested that compounds 1, 2 a, 2 b, 5, and 6 were able to attenuate CORT-induced apoptosis and damage, increase the levels of MMP and decrease Ca2+ inward flow in PC-12 cells.

Highly Promiscuous Flavonoid Di-O-glycosyltransferases from Carthamus tinctorius L.

Safflower (Carthamus tinctorius L.) has been recognized for its medicinal value, but there have been limited studies on the glycosyltransferases involved in the biosynthesis of flavonoid glycosides from safflower. In this research, we identified two highly efficient flavonoid O-glycosyltransferases, CtOGT1 and CtOGT2, from safflower performing local BLAST alignment. By constructing a prokaryotic expression vector, we conducted in vitro enzymatic reactions and discovered that these enzymes were capable of catalyzing two-step O-glycosylation using substrates such as kaempferol, quercetin, and eriodictyol. Moreover, they exhibited efficient catalytic activity towards various compounds, including flavones (apigenin, scutellarein), dihydrochalcone (phloretin), isoflavones (genistein, daidzein), flavanones (naringenin, glycyrrhizin), and flavanonols (dihydrokaempferol), leading to the formation of O-glycosides. The broad substrate specificity of these enzymes is noteworthy. This study provides valuable insights into the biosynthetic pathways of flavonoid glycosides in safflower. The discovery of CtOGT1 and CtOGT2 enhances our understanding of the enzymatic processes involved in synthesizing flavonoid glycosides in safflower, contributing to the overall comprehension of secondary metabolite biosynthesis in this plant species.

[A new neolignan glycoside from Acori Tatarinowii Rhizoma].

The main chemical constituents from Acori Tatarinowii Rhizoma were isolated and purified using the macroporous resin,microporous resin(MCI) and octadecylsilyl silica gel(ODS) column chromatography, as well as semi-preparative high performance liquid chromatography. Their chemical structures were elucidated by spectroscopic analyses including mass spectrometry(MS),nuclear magnetic resonance(NMR), ultraviolet(UV), infrared(IR) and circular dichoism(CD) combined with literature data.A total of 11 compounds were isolated and identified, including 4 lignan glycosides, 2 benzyl alcohol glycosides, 4 flavonoid glycosides, and 1 α-tetralone glycoside:(7S,8R)-dihydrodehydrodiconiferyl alcohol 9-O-ß-D-glucopyranosyl-9'-O-ß-D-glucopyranosyl-(1 → 6)-ß-D-glucopyranoside(1),(7S, 8R)-dihydrodehydrodiconiferyl alcohol 9-O-ß-D-glucopyranoside(2),(7S, 8R)-dihydrodehydrodiconiferyl alcohol di-9, 9'-O-ß-D-glucopyranoside(3),(+)-lyoniresinol 3α-O-ß-D-glucopyranoside(4), benzyl alcohol O-ß-D-glucopyranosyl-(1→6)-ß-D-glucopyranoside(5), benzyl alcohol O-ß-D-xylopyranosyl-(1→6)-ß-D-glucopyranoside(6), 3'-O-methylepicatechin 7-O-ß-D-glucopyranoside(7), 3'-O-methylcatechin 7-O-ß-D-glucopyranoside(8), apigenin 6-C-ß-D-glucopyranosyl-7-O-ß-D-glucopyranoside(9), isoscoparin 7-O-ß-D-glucopyranoside(10), and(4R)-8-hydroxy-α-tetralone-4-O-ß-D-glucopyranoside(11). Compound 1 is a new neolignan glycoside, and compounds 2-5 and 7-11 are isolated from genus Acorus for the first time.

Cross-Species Metabolomic Analyses in the Brassicaceae Reveals Common Responses to Ultraviolet-B Exposure.

Exposure to UV-B radiation, an intrinsic component of solar light, is detrimental to all living organisms as chromophore units of DNA, RNA and proteins readily absorb high-energy photons. Indirect damage to the same molecules and lipids is mediated by elevated reactive oxygen species (ROS) levels, a side effect of exposure to UV-B stress. To protect themselves from UV-B radiation, plants produce phytochemical sunscreens, among which flavonoids have shown to be particularly effective. The core aglycone of flavonoid molecules is subjected to chemical decoration, such as glycosylation and acylation, further improving sunscreen properties. In particular, acylation, which adds a phenolic ring to flavonoid molecules, enhances the spectral absorption of UV-A and UV-B rays, providing to this class of compounds exceptional shielding power. In this study, we comprehensively analyzed the responses to UV-B radiation in four Brassicaceae species, including Arabidopsis thaliana, Brassica napus, Brassica oleracea, and Brassica rapa. Our study revealed a complete reprogramming of the central metabolic pathway in response to UV-B radiation characterized by increased production of functional precursors of specialized metabolites with UV-B shielding properties, indicating a targeted effort of plant metabolism to provide increased protection. The analysis of specialized metabolites and transcripts revealed the activation of the phenylpropanoid-acetate pathway, leading to the production of specific classes of flavonoids and a cross-species increase in phenylacylated-flavonoid glucosides with synapoyl glycoside decorations. Interestingly, our analysis also revealed that acyltransferase genes of the class of serine carboxypeptidase-like (SCPLs) proteins are costitutively expressed, but downregulated in response to UV-B radiation, possibly independently of the ELONGATED HYPOCOTYL 5 (HY5) signaling pathway.

A comparison of consistent UV treatment versus inconsistent UV treatment in horticultural production of lettuce.

UV radiation is an underrated radiation currently missing in many horticultural production systems of vegetables in protected cultivation. It can be added e.g., in LED light sources. Using lettuce as a model plant, this study determined whether the use of UVB LEDs is suitable (1) for use in consistent systems (indoor farming) or (2) inconsistent systems (greenhouse). Blue and red LEDs were selected as additional artificial lighting to UVB LEDs. Both approaches led to a reproducible increase of desired flavonol glycosides, such as quercetin-3-O-(6''-O-malonyl)-glucoside or quercetin-3-O-glucuronide and the anthocyanin cyanidin-3-O-(6''-O-malonyl)-glucoside in lettuce. The impact of the consistent UVB treatment is higher with up to tenfold changes than that of the inconsistent UVB treatment in the greenhouse. Varying natural light and temperature conditions in greenhouses might affect the efficiency of the artificial UVB treatment. Here, UVB LEDs have been tested and can be recommended for further development of lighting systems in indoor farming and greenhouse approaches.

Efficient strategies for preparative separation of iridoid glycosides and flavonoid glycosides from Hedyotis diffusa.

Efficient strategies for the preparative separation of iridoid glycosides and flavonoid glycosides from Hedyotis diffusa using preparative high-performance liquid chromatography combined with appropriate pretreatment technologies were developed. Four fractions (Fr.1-1, Fr.1-2, Fr.1-3, and Fr.2-1) were firstly isolated from the crude extract of Hedyotis diffusa by column chromatography with C18, resin, and silica gel materials, respectively. Then, corresponding separation strategies were developed according to the polarity and chemical constituents. High-polar compounds of Fr.1-1 were purified by hydrophilic reversed-phase liquid chromatography and hydrophilic interaction liquid chromatography mode. The combination of C18 and phenyl columns realized the complementary separation of iridoid glycosides in Fr.1-2. Meanwhile, the improved selectivity caused by the change of organic solvent in the mobile phase was utilized to realize the purification of flavonoid glycosides in Fr.1-3 and Fr. 2-1. Finally, 27 compounds (purity > 95%) mainly involving nine iridoid glycosides and five flavonoid glycosides were obtained. A complete strategy was established for the separation of a complex sample with a wide polarity range, to jointly solve the problems of enrichment of target components and separation of structural analogs.

Systematic Quality Evaluation of Epimedium wushanense T. S. Ying Based on Two Quality Control Standards: Total Flavonoid Glycosides and Epimedin C.

Two quality control standards, total flavonoid glycosides of Epimedii Folium and epimedin C of Epimedii Wushanensis Folium, were used to systematically evaluate the quality of Epimedium wushanense T. S. Ying, so as to provide reference for its germplasm screening and resource utilization. Seven representative populations of E. wushanense covering its main distribution areas were uniformly sampled during the flowering period. There were significant quality differences among the populations of E. wushanense. According to the quality standard of total flavonoid glycosides, all populations were superior to the quality standard of the Chinese Pharmacopoeia for Epimedii Folium, with more than 1.5 % total flavonoid glycosides. The variation ranges of epimedin A, epimedin B, epimedin C, icariin and total flavonoid glycosides were 0.40-0.76 %, 0.51-0.83 %, 1.70-9.31 %, 0.40-1.23 % and 3.05-10.61 %, respectively. According to the quality standard of epimedin C, all populations were better than the quality standard of the Chinese Pharmacopoeia for Epimedii Wushanensis Folium, with more than 1.0 % epimedin C. The variation range of epimedin C was 2.22-10.06 %. When comparing the results of the two methods, a trend of slightly lower mean values was found for total flavonoid glycosides, except for the HBXW population. The quality of E. wushanense was superior to both the quality standard of Epimedii Folium and Epimedii Wushanense Folium in the Chinese Pharmacopoeia. Epimedin C was the most abundant component. Among the investigated populations, HBXW and HBGK exhibited the highest quality, and may provide excellent genetic resources for standardized cultivation. In addition, the habitat of these populations can also serve a reference for cultivation conditions.

Characterization of Polyphenols from Chenopodium botrys after Fractionation with Different Solvents and Study of Their In Vitro Biological Activity.

In the present work, we have investigated the polyphenolic composition of Chenopodium botrys from Bulgaria. The polyphenols were fractionated with solvents of varying polarity (n-hexane, chloroform, ethyl acetate, and n-butanol). The fractions were analyzed by HPLC-PDA and UHPLC-MS. The ethyl acetate fraction contained mono- and di-glycosides of quercetin, di-glycosides of kaempferol, and isorhamnetin and monoglycosides of hispidulin and jaceosidine. We found quercetin triglycosides in the butanol fraction. The ethyl acetate and butanol fractions contained 168.82 mg/g Extr and 67.21 mg/g Extr of quercetin glycosides, respectively. The main components of the polyphenolic complex in C. botrys were 6-methoxyflavones (355.47 mg/g Extr), which were found in the chloroform fraction. The flavonoids pectolinarigenin, demethylnobiletin, and isosinensetin, and the glycosides of quercetin (triglycosides, acylglycosides), kaempferol, isorhamnetin, hispidiulin, and jaceosidine, were discovered and reported in Chenopodium botrys for the first time. We used in vitro methods to assess the biological activity against oxidative stress (hydrogen peroxide scavenging activity (HPSA) and hydroxyl radical scavenging activity (HRSA)), nitrosative stress (nitric oxide scavenging activity (NOSA)), anti-inflammatory activity (IAD inhibition), and anti-tryptic activity (ATA). Quercetin mono- and di-glycosides exhibited greater HPSA and HRSA (IC50 = 39.18, 105.03 µg/mL), while 6-methoxyflavones had a greater NOSA (IC50 = 146.59 µg/mL). The same components showed the highest ATA (IC50 ranging from 116.23 to 202.44 µg/mL).

HPLC-DAD-MS Characterization, Antioxidant Activity, α-amylase Inhibition, Molecular Docking, and ADMET of Flavonoids from Fenugreek Seeds.

Fenugreek (Trigonella foenum-graecum) has a great beneficial health effect; it has been used in traditional medicine by many cultures. Likewise, the α-amylase inhibitors are potential compounds in the development of drugs for the treatment of diabetes. The beneficial health effects of fenugreek lead us to explore the chemical composition of the seeds and their antioxidant and α-amylase inhibition activities. The flavonoid extraction from fenugreek seeds was achieved with methanol through a Soxhlet apparatus. Then, the flavonoid glycosides were characterized using HPLC-DAD-ESI-MS analysis. The antioxidant capacity of fenugreek seed was measured using DPPH, FRAP, ABTS, and CUPRAC assays. Finally, the α-amylase inhibition activity was carried out using in vitro and in silico methods. The methanolic extract was found to contain high amounts of total phenolics (154.68 ± 1.50 µg GAE/mg E), flavonoids (37.69 ± 0.73 µg QE/mg E). The highest radical-scavenging ability was recorded for the methanolic extract against DPPH (IC50 = 556.6 ± 9.87 µg/mL), ABTS (IC50 = 593.62 ± 9.35 µg/mL). The ME had the best reducing power according to the CUPRAC (A 0.5 = 451.90 ± 9.07 µg/mL). The results indicate that the methanolic extracts of fenugreek seed best α-amylase inhibition activities IC50 = 653.52 ± 3.24 µg/mL. Twenty-seven flavonoids were detected, and all studied flavonoids selected have good affinity and stabilize very well in the pocket of α-amylase. The interactions between the studied flavonoids with α-amylase were investigated. The flavonoids from fenugreek seed present a good inhibitory effect against α-amylase, which is beneficial for the prevention of diabetes and its complications.

Characterization of UDP-glycosyltransferase family members reveals how major flavonoid glycoside accumulates in the roots of Scutellaria baicalensis.

BACKGROUND: Flavonoid glycosides extracted from roots of Scutellaria baicalensis exhibit strong pharmaceutical antitumor, antioxidative, anti-inflammatory, and antiviral activities. UDP glycosyltransferase (UGT) family members are responsible for the transfer of a glycosyl moiety from UDP sugars to a wide range of acceptor flavonoids. Baicalin is the major flavonoid glycoside found in S. baicalensis roots, and its aglycone baicalein is synthesized from a specially evolved pathway that has been elucidated. However, it is necessary to carry out a genome-wide study of genes involved in 7-O-glucuronidation, the final biosynthesis step of baicalin, which might elucidate the relationship between the enzymes and the metabolic accumulation patterns in this medicinal plant. RESULTS: We reported the phylogenetic analysis, tissue-specific expression, biochemical characterization and evolutionary analysis of glucosyltransferases (SbUGTs) and glucuronosyltransferases (SbUGATs) genes based on the recently released genome of S. baicalensis. A total of 124 UGTs were identified, and over one third of them were highly expressed in roots. In vitro enzyme assays showed that 6 SbUGTs could use UDP-glucose as a sugar donor and convert baicalein to oroxin A (baicalein 7-O-glucoside), while 4 SbUGATs used only UDP-glucuronic acid as the sugar donor and catalyzed baicalein to baicalin. SbUGAT4 and SbUGT2 are the most highly expressed SbUGAT and SbUGT genes in root tissues, respectively. Kinetic measurements revealed that SbUGAT4 had a lower Km value and higher Vmax/Km ratio to baicalein than those of SbUGT2. Furthermore, tandem duplication events were detected in SbUGTs and SbUGATs. CONCLUSIONS: This study demonstrated that glucosylation and glucuronidation are two major glycosylated decorations in the roots of S. baicalensis. Higher expression level and affinity to substrate of SbUGAT4, and expansion of this gene family contribute high accumulation of baicalin in the root of S. baicalensis.

Phytochemical, Antiplasmodial, and Cytotoxic Investigation of Euclea natalensis A.DC. subsp. natalensis Leaves.

Previous research shows that the root and bark extracts of Euclea natalensis have antiplasmodial activity, but the leaves have not been examined yet. This study investigated the phytochemical, antiplasmodial, and cytotoxic properties of the plant leaves. The activity against 3D7 Plasmodium falciparum was determined using the parasite lactate dehydrogenase assay, and the cytotoxicity against Vero and HeLa cells was evaluated using the MTT and resazurin assays, respectively. The bioactive compounds were isolated by chromatography, and their structures were established with spectroscopic and spectrometric techniques. The extract showed antiplasmodial activity (IC50 =25.6 µg/mL) and was not cytotoxic against Vero cells (IC50 =403.7 µg/mL). Purification of the extract afforded six flavonoid glycosides, four triterpenoids, and a coumarin. The glycosides showed antiplasmodial and cytotoxic activities, against HeLa cells, at 50 µg/mL, but the activity was reduced at 10 µg/mL. Naphthoquinones, which are among the predominant phytochemicals in the root and root bark of E. natalensis, were not detected in the leaves.

New flavonoid glycosides from Xanthium strumarium with their protein tyrosine phosphatase 1B inhibitory activity.

Two new flavonoid glycosides named 6-hydroxy-3-methoxy-apigenin 7-O-α-ʟ-rhamnopyranoside (1) and 3-hydroxyl-apigenin 8-C-ß-ᴅ-xylopyranoside (2), along with five known compounds (3-7), were isolated from Xanthium strumarium. Their structures were elucidated on the basis of spectroscopic and physicochemical analyses. All compounds were evaluated for in vitro inhibitory activity against PTP1B. Among them, compounds 1 and 5 showed significant inhibitory activity on PTP1B with IC50 values of 11.3 ± 1.7 and 8.9 ± 0.7 µM, respectively.

Identification of Antidiabetic Compounds from the Aqueous Extract of Sclerocarya birrea Leaves.

Diabetes, a prevalent metabolic condition with a wide range of complications, is fast becoming a global health crisis. Herbal medicine and enhanced extracts are some of the therapeutic options used in the management of diabetes mellitus. The plant-derived molecules and their suitable structure modification have given many leads or drugs to the world such as metformin used as an antidiabetic drug. The stem extract of Sclerocarya birrea has been reported as a potent antidiabetic (glucose uptake) agent. However, the bioactive compounds have not been reported from S. birrea for treatment of diabetes. In this study, the spray-dried aqueous leaf extracts of S. birrea were investigated as an antidiabetic agent using a 2-deoxy-glucose (2DG) technique showing good stimulatory effect on glucose uptake in differentiated C2C12 myocytes with % 2DG uptake ranging from 110-180% that was comparable to the positive control insulin. Three compounds were isolated and identified using bioassay-guided fractionation of the spray-dried aqueous extract of S. birrea leaves: myricetin (1), myricetin-3-O-ß-D-glucuronide (2) and quercetin-3-O-ß-D-glucuronide (3). Their chemical structures were determined using NMR and mass spectrometric analyses, as well as a comparison of experimentally obtained data to those reported in the literature. The isolated compounds (1-3) were studied for their stimulatory actions on glucose uptake in differentiated C2C12 myocytes. The three compounds (1, 2 and 3) showed stimulatory effects on the uptake of 2DG in C2C12 myocytes with % 2DG uptake ranging from 43.9-109.1% that was better compared to the positive control insulin. Additionally, this is the first report of the flavonoid glycosides (myricetin-3-O-ß-D-glucuronide) for antidiabetic activity and they are the main bioactive compound in the extract responsible for the antidiabetic activity. This result suggests that the S. birrea leaves have the potential to be developed for treatment of diabetes.

Hydrolyzed Flavonoids from Cyrtosperma johnstonii with Superior Antioxidant, Antiproliferative, and Anti-Inflammatory Potential for Cancer Prevention.

Cyrtosperma johnstonii is one of the most interesting traditional medicines for cancer treatment. This study aimed to compare and combine the biological activities related to cancer prevention of the flavonoid glycosides rutin (RT) and isorhamnetin-3-o-rutinoside (IRR) and their hydrolysis products quercetin (QT) and isorhamnetin (IR) from C.johnstonii extract. ABTS and MTT assays were used to determine antioxidant activity and cytotoxicity against various cancer cells, as well as normal cells. Anti-inflammatory activities were measured by ELISA. The results showed that the antioxidant activities of the compounds decreased in the order of QT > IR > RT > IRR, while most leukemia cell lines were sensitive to QT and IR with low toxicity towards PBMCs. The reduction of IL-6 and IL-10 secretion by QT and IR was higher than that induced by RT and IRR. The combination of hydrolysis products (QT and IR) possessed a strong synergism in antioxidant, antiproliferative and anti-inflammatory effects, whereas the combination of flavonoid glycosides and their hydrolysis products revealed antagonism. These results suggest that the potential of the combination of hydrolyzed flavonoids from C. johnstonii can be considered as natural compounds for the prevention of cancer.

Bioassay-Guided Isolation of New Flavonoid Glycosides from Platanus × acerifolia Leaves and Their Staphylococcus aureus Inhibitory Effects.

Despite the rapid advances in drug R&D, there is still a huge need for antibacterial medications, specifically for the methicillin-resistant Staphylococcus aureus (MRSA). Inspired by the research where a viable class of MRSA inhibitors was found in the species Platanus occidentalis, a S. aureus inhibition screening-guided phytochemical reinvestigation on Platanus × acerifolia (London plane tree) leaves were performed with four flavonoid glycosides garnered, including two new compounds, quercetin-3-O-α-l-(2″-E-p-coumaroyl-3″-Z-p-coumaroyl)-rhamnopyranoside (E,Z-3'-hydroxyplatanoside, 1) and quercetin-3-O-α-l-(2″-Z-p-coumaroyl-3″-E-p-coumaroyl)-rhamnopyranoside (Z,E-3'-hydroxyplatanoside, 2). All of the isolates showed significant S. aureus ATCC 25904 inhibitory activity with MICs ranging from 4 to 64 µg/mL, suggesting the potential of discovering drug leads for the control of S. aureus from such a rich, urban landscaping plant in the Platanus genus.

Analyses of Physical and Chemical Compositions of Different Medicinal Specifications of CRPV by Use of Multiple Instrumental Techniques Combined with Multivariate Statistical Analysis.

Citri Reticulatae Pericarpium Viride (CRPV) is the processed product of Citrus reticulata Blanco. We systematically analyzed two CRPV types, Geqingpi (GQP) and Sihuaqingpi (SHQP), based on powder color, microscopic characteristics, and chemical composition. In addition, we characterized their constituents via ultra-high-performance liquid chromatography with hybrid quadrupole-orbitrap mass spectrometry (UHPLC-Q-Exactive Orbitrap-MS). Both showed significant differences in their powder color and microscopic characteristics. Fourier-transform infrared (FT-IR) spectroscopic analysis results showed that the C=O peak absorption of carboxylic acids and their carbonyl esters in SHQP was higher than that of GQP, while the C-OH and C-H plane bending peaks of polysaccharides were lower than those of GQP. We analyzed these data via similarity analysis, PCA, and OPLS-DA. GQP and SHQP had large distinct differences. Based on the mass measurements for molecular and characteristic fragment ions, we identified 44 main constituents from CRPV, including different flavonoid glycosides and flavonoid aglycones in SHQP and GQP, respectively. We found luteolin-6-C-glucoside, orientin, rhoifolin, and pilloin solely in SHQP, and naringenin and hesperetin only in GQP. The peak area measurements showed GQP having a higher flavonoid glycoside (narirutin, hesperidin, etc.) content, whereas SHQP had a higher polymethoxyflavone (nobiletin, tangeretin, etc.) content. Since we holistically analyzed two CRPV types, the results can not only support future pharmacological research, but also provide a scientific basis for formulating more reasonable CRPV quality standards and guide its clinical potential as a precision medicine.

HPLC coupled with quadrupole time of flight tandem mass spectrometry for analysis of glycosylated components from the fresh flowers of two congeneric species: Robinia hispida L. and Robinia pseudoacacia L.

Developing methods for the systematic and rapid identification of the chemical compositions of fresh plant tissues has long attracted the attention of phytochemists and pharmacologists. In the present study, based on highly efficient sample pretreatment and high-throughput analysis of high-performance liquid chromatography coupled with quadrupole time of flight tandem mass spectrometry data using molecular networks, a method was developed for systematically analyzing the chemical constituents of the fresh flowers of Robinia hispida L. and Robina pseudoacacia L., two congeneric ornamental species that lack prior consideration. A total of 44 glycosylated structures were characterized. And on the basis of establishing of the fragmentation pathways of 11 known flavonoid glycosides, together with the molecular networking analysis, 18 other ions of flavonoid glycosides in five classes were clustered. Moreover, 15 soyasaponins/triterpenoid glycosides were tentatively identified by comparison of their tandem mass spectrometry characteristic ions with those reported in the literature or the online Global Natural Product Social Molecular Networking database. The water extracts were separated by flash chromatography, which resulted in the discovery of one new compound, named rohispidascopolin, along with five known entities. The pharmacological targets were predicted by SwissTargetPrediction.

Antiplasmodial and Cytotoxic Activities of Extract and Compounds from Ozoroa obovata (Oliv.) R. & A. Fern. var. obovata.

Ozoroa obovata (Oliv.) R. & A. Fern. var. obovata found in KwaZulu-Natal in South Africa was investigated for phytochemical constituents, and for antiplasmodial and cytotoxic effects. The plant leaves were collected from the University of KwaZulu-Natal (UKZN) arboretum on the Pietermaritzburg Campus, in March 2019. The inhibitory activity against 3D7 Plasmodium falciparum was determined using the parasite lactate dehydrogenase (pLDH) assay and cytotoxicity against HeLa cells was evaluated using the resazurin assay. The bioactive compounds were isolated by chromatographic purification and their structures were established with spectroscopic and spectrometric techniques. The plant leaf extract displayed significant antiplasmodial activity at 50 µg/mL and was also cytotoxic against HeLa cells. Chromatographic purification of the extract led to the isolation of two biflavonoids, four flavonoid glycosides, a steroid glycoside, and a megastigmene derivative. The compounds displayed antiplasmodial and antiproliferative activities at 50 µg/mL but the activity was substantially reduced at 10 µg/mL. The activities and compounds are being reported in O. obovata for the first time.

Flavonoid glycosides from the fruits of Embelia ribes and their anti-oxidant and α-glucosidase inhibitory activities.

Three new flavonoid glycosides, embeliaflavosides A-C (1-3), together with eight known flavonoid glycosides (4-11), were isolated from the fruits of Embelia ribes. Their structures were established based on the analyses of spectroscopic data. Compounds 1-11 were evaluated for antioxidant and α-glucosidase inhibitory activities. The results revealed that compounds 1-11 owned significant ABTS radical scavenging activity with IC50 values of 2.52-9.78 µM, and DPPH scavenging activity with IC50 values of 7.56-26.47 µM, respectively. However, α-glucosidase inhibition assay indicated that all the isolates were inactive.[Formula: see text].