New cytotoxic flavonoids from aerial parts of Platycladus orientalis L

Phytochemistry and pharmacology of natural prenylated flavonoids

Prenylated flavonoids are a special kind of flavonoid derivative possessing one or more prenyl groups in the parent nucleus of the flavonoid. The presence of the prenyl side chain enriched the structural diversity of flavonoids and increased their bioactivity and bioavailability. Prenylated flavonoids show a wide range of biological activities, such as anti-cancer, anti-inflammatory, neuroprotective, anti-diabetic, anti-obesity, cardioprotective effects, and anti-osteoclastogenic activities. In recent years, many compounds with significant activity have been discovered with the continuous excavation of the medicinal value of prenylated flavonoids, and have attracted the extensive attention of pharmacologists. This review summarizes recent progress on research into natural active prenylated flavonoids to promote new discoveries of their medicinal value.

Chemotaxonomic Variation in Volatile Component Contents in Ancient Platycladus orientalis Leaves with Different Tree Ages in Huangdi Mausoleum

To gain insight into the differences in the composition and volatile components content in ancient Platycladus orientalis leaves with different tree ages in Huangdi Mausoleum, the volatile components were identified by headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS) method. The volatile components were statistically analyzed by orthogonal partial least squares discriminant analysis and hierarchical cluster analysis, and the characteristic volatile components were screened. The results exhibited that a total of 72 volatile components were isolated and identified in 19 ancient Platycladus orientalis leaves with different tree ages, and 14 common volatile components were screened. Among them, the contents of α-pinene (6.40-16.76%), sabinene (1.11-7.29%), 3-carene (1.14-15.12%), terpinolene (2.17-4.95%), caryophyllene (8.04-13.53%), α-caryophyllene (7.34-14.41%), germacrene D (5.27-12.13%), (+)-Cedrol (2.34-11.30%) and α-terpinyl acetate (1.29-25.68%) were relatively higher (>1%), accounting for 83.40-87.61% of the total volatile components. Nineteen ancient Platycladus orientalis trees were clustered into three groups through the HCA method based on the 14 common volatile components content. Combined with the results of OPLS-DA analysis, (+)-cedrol, germacrene D, α-caryophyllene, α-terpinyl acetate, caryophyllene, β-myrcene, β-elemene and epiglobulol were the differential volatile components to distinguish ancient Platycladus orientalis with different tree ages. The results revealed that the composition of the volatile components in ancient Platycladus orientalis leaves with different tree ages was different, showing different aroma characteristics, which provided a theoretical reference for the differential development and application of volatile components in ancient Platycladus orientalis leaves.

Three new dihydroflavonols with free radical scavenging activity from Ribes himalense Royle ex Decne

Ribes himalense Royle ex Decne, a small shrub, is widely used as a Tibetan medicine in Chinese folk. In this study, three novel 1,1-diphenyl-2-picrylhydrazyl inhibitors named Rihimaside A, Rihimaside B, and Rihimaside C, as well as one known 1,1-diphenyl-2-picrylhydrazyl inhibitor, dihydromyricetin, were isolated from the leaves and stems of Ribes himalense Royle ex Decne using online high performance liquid chromatography-1,1-diphenyl-2-picrylhydrazyl activity screening system combined with medium and high-pressure liquid chromatography. All four 1,1-diphenyl-2-picrylhydrazyl inhibitors are dihydroflavonols. The 1,1-diphenyl-2-picrylhydrazyl scavenging activity and IC₅₀ values of three novel 1,1-diphenyl-2-picrylhydrazyl inhibitors were determined using 1,1-diphenyl-2-picrylhydrazyl methods. Rihimaside A, Rihimaside B, and Rihimaside C exhibited IC₅₀ values of 9.58 μg/mL, 12.57 μg/mL and 387 μg/mL, respectively.

Chemical profiling and identification of anti-inflammatory biomarkers of oriental Thuja (Platycladus orientalis) using UPLC/MS/MS and network pharmacology-based analyses

Platycladus orientalis L. Franco has many folk uses as it is mainly used to treat inflammatory ailments. UPLC-MS/MS was used for the chemical profiling of P. orientalis leaves. Identified metabolites were forwarded to network pharmacology analysis. Networks were constructed based on STITCH, SEA, DAVID, KEGG and STRING databases and using Cytoscape. The identified hit compounds were afzelin, myricetin, apigenin-7-O-hexoside, quercetrin and hyperoside. IL2, VEGFA, AKT1, AKT2, CREB1, IL5, RPS6KB1 and TNF were the main inflammation-related targets identified. Quercetrin and hyperoside were tested for their anti-inflammatory activity. it can be concluded that, the identified hit compounds exhibited strong synergistic interactions with the inflammation and immunity-related targets and pathways.

A mitochondria-targeted fluorescent probe for monitoring endogenous cysteine in living cells and zebrafish

At the organelle level, pathogenesis due to abnormal concentrations of cysteine (Cys) is of great significance for the early diagnosis and treatment of related diseases. Generally speaking, organelle localization requires the participation of specific target groups, which increases the difficulty of synthesis. Herein, through simple synthesis, a novel biflavone derivative (BFD) that exhibits excited-state intramolecular proton transfer (ESIPT) was obtained and successfully located in mitochondria without target groups. The probe BFD can distinguish Cys from Hcy and GSH with a rapid response (< 5 s) and showed visual detection for Cys with a large Stokes shift (about 260 nm). Because of its nanomorphology in solution and surface functional groups, the probe BFD can enter the cell smoothly and achieve mitochondrial localization. Owing to its excellent optical performance, the probe BFD was successfully applied to the imaging of endogenous Cys in HeLa cells and zebrafish.

Seasonal dynamics of the phenolic constituents of the cones and leaves of oriental Thuja (Platycladus orientalis L.) reveal their anti-inflammatory biomarkers

In this study, the seasonal dynamics of the flavonoids in the cones and leaves of oriental Thuja (Platycladus orientalis L. Franco) as well as the in vitro anti-inflammatory activity of their extracts were investigated. The important chemical markers of the studied extracts were determined using untargeted HPTLC profiling, which was further utilized to assess the seasonality effect on the composition of these metabolites over three seasonal cycles. A quantitative HPTLC method was developed and validated for the identified chemical markers of oriental Thuja: hyperoside, quercetrin, isoscutellarein-7-O-β-xyloside, cupressuflavone, hinokiflavone, sotetsuflavone and isoscutellarein-8-methyl ether. The highest amounts of flavonoids were observed during the summer and winter seasons, where the leaves possessed higher contents of flavonoids compared to cones. Flavone glycosides are a major class of flavones encountered in leaves, while the cones mainly accumulated biflavones. The results showed that the effect of seasonal variation on the accumulation of flavonoids within the cones was less pronounced than in the leaves. The summer leaves showed a remarkable reduction in the levels of INF-γ, where the value decreased to 80.7 ± 1.25 pg mL-1, a significantly lower level than that obtained with piroxicam (180 ± 1.47 pg mL-1); this suggests a noteworthy anti-inflammatory potential. OPLS (orthogonal projection to latent structures) models showed that flavonoidal glycosides, quercetrin, hyperoside and isoscutellarein-7-O-β-xyloside were the most contributing biomarkers to the reduction in pro-inflammatory mediators in LPS-stimulated WBCs. The results obtained in the study can thus be exploited to establish the best organs as well as the optimal periods of the year for collecting and obtaining certain biomarkers at high concentrations to guarantee the efficacy of the obtained extracts.

New approach in the characterization of bioactive compounds isolated from Calycotome spinosa (L.) Link leaves by the use of negative electrospray ionization LITMSn, LC-ESI-MS/MS, as well as NMR analysis

Two novel compounds were isolated for the first time from Calycotome spinosa (L.) Link, an alkaloid 5-Hydroxy-1H-indole (4) and a cyclitol D-pinitol (5), together with the three well-known flavonoids; Chrysin-7-O-(β-D-glucopyranoside) (1), Chrysin-7-O-β-D-(6″-acetyl)glycopyranoside (2) and Apigenin-7-O-β-D-glycopyranoside (3). The chemical structures of the isolated compounds were elucidated by spectroscopic data and mass spectrometric analyses; including a fresh approach 1D-NMR, 2D-NMR with LC-ESI-MS/MS. In this study, the new compound (4) that has been obtained from the leaves MeOH extract presented the best radical scavenging activity (DPPH) (IC₅₀ < 10 µg/mL) compared to the standard butylated hydroxytoluene (BHT, IC₅₀ = 34.73 ± 0.23 μg/mL) and showed the highest total antioxidant capacity (TAC = 985.54 ± 0.13 mg AAE/g extract) in contrast to ascorbic acid (TAC = 905.95 ± 0.07 mg AAE/g extract). Furthermore, the strongest reducing power (EC₅₀ = 344.82 ± 0.02 µg/mL), as well as the remarkable scavenging potential by ABTS assay (IC₅₀ = 7.8 ± 0.43 µg/mL), were exhibited by the same composite (4). Followed by the methanol crude extract and the compound (3) that also showed a potent antioxidant (DPPH; IC₅₀ = 41.04 ± 0.15 and 47.36 ± 0.21 µg/mL, TAC; 671.02 ± 0.21 and 608.67 ± 0.34 mg AAE/g extract, FRAP; EC₅₀ = 763.73 ± 0.32 and 814.61 ± 0.31 µg/mL, ABTS; IC₅₀ = 19.18 ± 0.06 and 63.72 ± 0.64 µg/mL, respectively), but less than the previous samples. On the opposite side, compound (5) had the lowest activity, in which its values were less interesting to determine. Moreover, compound (4) has equally exerted an attractive antibacterial activity against Staphylococcus aureus (ATTC-25923), Pseudomonas aeruginosa (ATTC- 27853) and Salmonella abony (NCTC 6017), as measured by the disc diffusion assay, with inhibition zones of 16 ± 0.5, 9.83 ± 0.29 and 8 ± 0.28 mm, in that order. To the best of our knowledge, 5-Hydroxy-1H-indole was isolated from plants for the second time in our current work. Thus, the obtained results from this investigation propose that the leaves of C. spinosa are a rich natural source for value molecules as potential antioxidants and antimicrobial agents for best human health.