In this study, the inhibitory potential of bacterial neuraminidase (NA) was observed on the leaves of
Nakai, which is a popular ingredient in traditional herbal medicine. This study attempted to ...isolate the relevant, responsible metabolites and elucidate their inhibition mechanism. The methanol extraction process yielded eight flavonoids (
⁻
), of which compounds
and
were new compounds named koreanoside F and koreanoside G, respectively. All the compounds (
⁻
) showed a significant inhibition to bacterial NA with IC
values of 0.17⁻106.3 µM. In particular, the prenyl group on the flavonoids played a critical role in bacterial NA inhibition. Epimedokoreanin B (compound
, IC
= 0.17 µM) with two prenyl groups on C8 and C5' of luteolin was 500 times more effective than luteolin (IC
= 85.6 µM). A similar trend was observed on compound
(IC
= 0.68 µM) versus dihydrokaempferol (IC
= 500.4 µM) and compound
(IC
= 12.6 µM) versus apigenin (IC
= 107.5 µM). Kinetic parameters (
,
, and
/
) evaluated that all the compounds apart from compound
showed noncompetitive inhibition. Compound
was proven to be a mixed type inhibitor. In an enzyme binding affinity experiment using fluorescence, affinity constants (
) were tightly related to inhibitory activities.
In this study, the changes in free amino acids of soybean leaves after ethylene application were characterized based on quantitative and metabolomic analyses. All essential and nonessential amino ...acids in soybean leaves were enhanced by fivefold (250 to 1284 mg/100 g) and sixfold (544 to 3478 mg/100 g), respectively, via ethylene application. In particular, it was found that asparagine is the main component, comprising approximately 41% of the total amino acids with a twenty-five fold increase (78 to 1971 mg/100 g). Moreover, arginine and branched chain amino acids (Val, Leu, and Ile) increased by about 14 and 2-5 times, respectively. The increase in free amino acid in stem was also similar to the leaves. The metabolites in treated and untreated soybean leaves were systematically identified by gas chromatography-mass spectrometry (GC-MS), and partial variance discriminant analysis (PLS-DA) scores and heat map analysis were given to understand the changes of each metabolite. The application of ethylene may provide good nutrient potential for soybean leaves.
s Merr. et Rolfe has been cultivated on a large scale and is widely consumed by local inhabitants as an important nutraceutical, especially against rheumatism which has a deep connection with ...antioxidants. In this study, a total of 18 different phenolic metabolite compounds in
s were isolated and identified, and evaluated for their antioxidant and DNA damage protection potential. The antioxidant activity of the 18 identified compounds was screened using DPPH, ORAC, hydroxyl and superoxide radical scavenging assays. The antioxidant potential of the compounds was found to differ by functionality and skeleton. However, most compounds showed a good antioxidant potential. In particular, seven of the identified compounds, namely, compounds
,
,
,
,
,
and
, showed significant protective effects on pBR322 plasmid DNA against the mutagenic and toxic effects of Fenton's reaction. The most active compound, compound
, displayed a dose-dependent DNA damage protection potential in the range of 7.5~60.0 μM. The DNA damage protective effect of the identified compounds was significantly correlated with the hydroxyl radical scavenging activity. Compounds that exhibited effective (IC
= 5.4~12.5 μg/mL) hydroxyl radical scavenging activity were found to be the ones with higher DNA damage protection potential.
The aim of this study is to explore anti-inflammatory phytochemicals from
based on the inhibition of pro-inflammatory enzyme, human neutrophil elastase (HNE) and anti-inflammatory activities in ...lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage. Three stereoisomers of iridal-type triterpenoids (
-
) were isolated from the roots of
and their stereochemistries were completely identified by NOESY spectra. These compounds were confirmed as reversible noncompetitive inhibitors against HNE with IC
values of 6.8-27.0 µM. The binding affinity experiment proved that iridal-type triterpenoids had only a single binding site to the HNE enzyme. Among them, isoiridogermanal (
) and iridobelamal A (
) displayed significant anti-inflammatory effects by suppressing the expressions of pro-inflammatory cytokines, such as iNOS, IL-1β, and TNF-α through the NF-κB pathway in LPS-stimulated RAW264.7 cells. This is the first report that iridal-type triterpenoids are considered responsible phytochemicals for anti-inflammatory effects of
.
Xanthine oxidase is a frontier enzyme to produce oxidants, which leads to inflammation in the blood. Prenylated isoflavones from
were found to display potent inhibition against xanthine oxidase (XO). ...All isolates (
-
) inhibited XO enzyme with IC
ranging 7.8~36.4 μM. The most active isoflavones (
-
, IC
= 7.8~14.8 μM) have the structural feature of a catechol motif in B-ring. Inhibitory behaviors were disclosed as a mixed type I mode of inhibition with
<
. Binding affinities to XO enzyme were evaluated. Fluorescence quenching effects agreed with inhibitory potencies (IC
s). The compounds (
-
) also showed potent anti-LDL oxidation effects in the thiobarbituric acid-reactive substances (TBARS) assay, the lag time of conjugated diene formation, relative electrophoretic mobility (REM), and fragmentation of apoB-100 on copper-mediated LDL oxidation. The compound
protected LDL oxidation with 0.7 μM in TBARS assay, which was 40-fold more active than genistein (IC
= 30.4 μM).
Abundance of metabolites in plant is a critical factor toward being functional food stuff. Salicylic acid (SA) treatment led significant changes in levels of the secondary metabolites in soybean ...roots. Notably, the exposure of 3 mM of SA aqueous solution to soybean plants for 24 h resulted in distinctive increases in the levels of coumestrol (16-fold, 0.3–4.8 mg/g DW) and daidzein (7-fold, 1.2–8.9 mg/g DW) in roots part. These changes were systematically investigated by LC-ESI-TOF/MS analysis to afford a clear difference of PLS-DA score, heatmap, and box plots. Quantitative analysis showed that SA treatment played to stimulate biosynthesis of coumestrol as well as hydrolysis of its glycosides (coumestrin and malonylcoumestrin). The highly improved anti-LDL oxidation effect was observed in the SA treated soybean roots in the three different assay systems. It might be rationalized by the increased levels of coumestrol and daidzein.
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•Quercetin derivatives (1-13) including the new (2) were isolated from M. glabra.•O-Alkylated quercetins were selective inhibitory potential toward hAChE and BACE1.•All compounds from ...M. glabra had a significant antioxidant potentials.•LC-ESI-Q-TOF/MS disclosed inhibitors as main metabolite of M. glabra leave extract.
Intensive investigation of phytochemicals from edible Melicope glabra leaves provided a series of O-alkylated quercetins (1–13). The quercetin 1 bearing prenyl and methyl motif showed potent inhibition to human acetylcholinesterase (hAChE) with mixed type I mode, while quercetin was inactive. The position of methyl group was also a critical factor to hAChE inhibition: 1 (4′-O-methyl, IC50 = 12.7 μM) vs2 (3′-O-methyl, IC50 = 119 μM). Inhibitory potency was doubly confirmed with the binding affinity (KSV) based on fluorescence quenching. O-Methyl groups on quercetin were observed to influence β-secretase (BACE1) inhibition. Thus, O-methylated quercetins (4–6) displayed potential inhibitions against BACE1 with IC50 values of 1.3, 4.1, and 14.1 μM, respectively. All compounds (3–6) have noncompetitive mode to BACE1. Additionally, all quercetin derivatives (1–13) had antioxidant potentials against different radical sources (ABTS, ORAC and FRAP). The UPLC-ESI-Q-TOF/MS indicated that the leaves part had promising metabolites towards hAChE and BACE1 inhibitions, which are the most predominant phytochemicals.
Soybean, a vital protein-rich crop, offers bioactivity that can mitigate various chronic human diseases. Nonetheless, soybean breeding poses a challenge due to the negative correlation between ...enhanced protein levels and overall productivity. Our previous studies demonstrated that applying gaseous phytohormone, ethylene, to soybean leaves significantly boosts the accumulation of free amino acids, particularly asparagine (Asn). Current studies also revealed that ethylene application to soybeans significantly enhanced both essential and non-essential amino acid contents in leaves and stems. Asn plays a crucial role in ammonia detoxification and reducing fatigue. However, the molecular evidence supporting this phenomenon remains elusive. This study explores the molecular mechanisms behind enhanced Asn accumulation in ethylene-treated soybean leaves. Transcriptional analysis revealed that ethylene treatments to soybean leaves enhance the transcriptional levels of key genes involved in Asn biosynthesis, such as aspartate aminotransferase (AspAT) and Asn synthetase (ASN), which aligns with our previous observations of elevated Asn levels. These findings shed light on the role of ethylene in upregulating Asn biosynthetic genes, subsequently enhancing Asn concentrations. This molecular insight into amino acid metabolism regulation provides valuable knowledge for the metabolic farming of crops, especially in elevating nutraceutical ingredients with non-genetic modification (GM) approach for improved protein content.
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•Eight human neutrophil elastase (HNE) inhibitors were isolated from the flowers of Hypericum ascyron.•Ascyronones E-G were identified as new polycyclic polyprenylated ...acylphloroglucinols (PPAPs).•The isolated acylphloroglucinols showed a significant HNE inhibition with noncompetitive behavior.
In the course of an investigation of human neutrophil elastase (HNE) associated with inflammation, the extract of the flower parts of Hypericum ascyron showed a significant influence to HNE. The responsible metabolites to HNE inhibition were found to be eight polyprenylated acylphloroglucinols, PPAPs (1–8) which showed IC50 ranges between 2.4 and 19.9 μM. This is the first report to demonstrate that PPAP skeleton exhibits potent HNE inhibition. The compounds 1–3 were characterized and newly named as ascyronone E (IC50 = 4.3 μM), ascyronone F (IC50 = 19.9 μM), ascyronone G (IC50 = 4.5 μM) based on 2D-NMR spectroscopic data. In the kinetic analysis of double reciprocal plots, all the compounds showed noncompetitive behaviors to HNE enzyme with the remaining of Km and the increase of Vmax. The binding affinity levels (KSV) by using fluorescence were sufficient to be able to prove that PPAPs (1–8) had compliant interaction with inhibitory potencies.
Neutrophil elastases are deposited in azurophilic granules interspace of neutrophils and tightly associated with inflammatory ailments. The root barks of
Artocarpus elasticus
had a strong inhibitory ...potential against human neutrophil elastase (HNE). The responsible components for HNE inhibition were confirmed as alkylated flavones (
2
–
4
, IC
50
= 14.8 ~ 18.1 μM) and dihydrobenzoxanthones (
5
–
8
, IC
50
= 9.8 ~ 28.7 μM). Alkyl groups on flavone were found to be crucial functionalities for HNE inhibition. For instance, alkylated flavone
2
(IC
50
= 14.8 μM) was 20-fold potent than mother compound norartocarpetin (
1
, IC
50
> 300 μM). The kinetic analysis showed that alkylated flavones (
2
–
4
) were noncompetitive inhibition, while dihydrobenzoxanthones (
5
–
8
) were a mixed type I (
K
I
<
K
IS
) inhibitors, which usually binds with free enzyme better than to complex of enzyme–substrate. Inhibitors and HNE enzyme binding affinities were examined by fluorescence quenching effect. In the result, the binding affinity constants (
K
SV
) had a significant correlation with inhibitory potencies (IC
50
).
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