Phenolic constituents with antibacterial activity from Eleutherine bulbosa.

Eleutherine bulbosa (Mill.) Urb. is a medicinal and edible plant with various benefits for humans and animals. In this work, four new phenolic constituents (1-4), along with six known phenolic compounds (5-10) were obtained from the red bulbs of E. bulbosa. Their structures with absolute configurations were characterized by extensive spectroscopic analysis, combined with HR-ESI-MS and quantum mechanical electronic circular dichroism (ECD). Compounds 1 and 2 are novel homologous and heterodimers, respectively, featuring an unusual spiro ring system. All isolated phenolic constituents were tested for their antibacterial effects. The results revealed four phenolic compounds 1-3 and 7 showed moderate antibacterial activity against Bacillus subtilis, Staphylococcus aureus and Escherichia coli with minimum inhibitory concentration (MIC) values ranging from 15.6 to 250.0 µg/mL.

Carbon Dots Derived from Traditional Chinese Medicines with Bioactivities: A Rising Star in Clinical Treatment.

In the field of carbon nanomaterials, carbon dots (CDs) have become a preferable choice in biomedical applications. Based on the concept of green chemistry, CDs derived from traditional Chinese medicines (TCMs) have attracted extensive attention, including TCM charcoal drugs, TCM extracts, and TCM small molecules. The design and preparation of CDs from TCMs (TCMs-CDs) can improve the inherent characteristics of TCMs, such as solubility, particle size distribution, and so on. Compared with other precursor materials, TCMs-CDs have outstanding intrinsic bioactivities and potential pharmacological effects. However, the research of TCMs-CDs in biomedicine is not comprehensive, and their mechanisms have not been understood deeply either. In this review, we will provide concise insights into the recent development of TCMs-CDs, with a major focus on their preparation, formation, precursors, and bioactivities. Then we will discuss the perfect transformation from TCMs to TCMs-CDs. Finally, we discuss the opportunities and challenges for the application of TCMs-CDs in clinical treatment.

Gram-Scale Total Synthesis of TAB with Cardioprotective Activity and the Structure-Activity Relationship of Its Analogs.

Traditional Chinese medicine has been proven to be of great significance in cardioprotective effects. Clinopodium chinense (Lamiaceae) has unique advantages in the treatment and prevention of cardiovascular diseases. Tournefolic acid B (TAB) was proven to be a potent component against myocardial ischemia reperfusion injury (MIRI) from Clinopodium chinense (Lamiaceae). This article will attempt to establish a gram-scale synthesis method of TAB and discuss the structure-activity relationship of its analogs. The total synthesis of TAB was completed in 10 steps with an overall yield of 13%. In addition, analogs were synthesized, and their cardioprotective activity was evaluated on the hypoxia/reoxygenation of H9c2 cells. Amidation of the acid position is helpful to the activity, while methylation of phenolic hydroxyl groups greatly decreased the cardioprotective activity. The easily prepared azxepin analogs also showed cardioprotective activity. Most of the clogP values calculated by Molinspiration ranged from 2.5 to 5, which is in accordance with Lipinski's rule of 5. These findings represent a novel kind of cardioprotective agent that is worthy of further study.

New naphtoquinones derivatives from the edible bulbs of Eleutherine americana and their protective effect on the injury of human umbilical vein endothelial cells.

Seven new naphthoquinone derivatives, named eleutherins A-G (1-7), were isolated from the edible bulbs of Eleutherine americana (Hong-Cong), which belongs to the Iridaceae family. Their structures were elucidated on the basis of spectroscopic analysis including high-resolution-electron spray ionization-mass spectrometry (HR-ESI-MS) and 1D and 2D nuclear magnetic resonance (NMR) techniques. The absolute configurations of compounds 1-4 were determined by experimental and calculated data. Additionally, a hypothetical biosynthetic pathway of 1-7 was postulated. All the isolates were evaluated for their protective effect against the injury of human umbilical vein endothelial cells (HUVECs) in vitro. Eleutherins A and B (1-2) showed a potential protective effect on microvessels.

Congmujingnosides B-G, triterpene saponins from the stem of Aralia chinensis and their protective effects against H2O2-induced myocardial cell injury.

Phytochemical investigation of the stem of Aralia chinensis yielded six new oleanane-type triterpene saponins named as congmujingnosides B-G (1-6). The new ones were elucidated on the basis of the chemical and spectroscopic analysis. Protective effects of compounds 1-6 were tested against H2O2-induced H9c2 cardiomyocyte injury, and the data showed that compounds 1 and 5 had significant cell-protective effects. No significant DPPH radical scavenging activity was observed for compounds 1-6.

Quantitative Evaluation of Twelve Major Components of Sulfur-Fumigated Astragali Radix with Different Durations by UPLC-MS.

In this study, an improved UPLC-MS (Ultra-high performance liquid chromatography-tandem mass spectrometry) method for simultaneously quantifying twelve major components belonging to two chemical types was developed and validated, and was applied to quantitatively compare the quality of sulfur-fumigated Astragali Radix of different durations and of the fresh reference sample. The results showed that the contents of triterpenes astragaloside III and astragaloside IV decreased moderately, while the flavonoids calycosin, formononetin, and 7,2'-dihydroxy-3',4'-dimethoxyisoflavane decreased significantly. The corresponding flavonoid glycosides increased accordingly, which indicated the occurrence of chemical transformation of flavonoids and glycosides in the process of sulfur-fumigation. These transformations were further confirmed by the synthesis of flavonoid glycosides under simulated sulfur-fumigation circumstances. Furthermore, the sulfur-fumigated duration varied in proportion with the contents of compounds 7, 11, and 12. These results suggest that the established method was precise, accurate and sensitive enough for the global quality evaluation of sulfur-fumigated Astragali Radix. Further, sulfur-fumigation not only changes the proportions of bioactive components, but also causes chemical transformation in Astragali Radix.

New polyoxypregnane glycosides from Aspidopterys obcordata vines with antitumor activity.

Nine new polyoxypregnane glycosides, obcordatas A-I (1-9), were isolated from Aspidopterys obcordata Hemsl vines. Their structures were elucidated by extensive spectroscopic methods. Separated compounds were evaluated for antitumor activities against the human cancer cell lines AGS, SW480, HuH-7 and MCF-7, and compounds 1-6 and 9 showed selective cytotoxicity against HuH-7 cells with IC50 values of 8.7, 10.2, 7.5, 12.1, 16.5, 14.3, and 17.4 µM, respectively. Flow cytometry experiments showed that the effects of compound 1 on the cell cycle were attributable to cell cycle arrest at G1/S phase.

Cucurbitane-type triterpenes from the tubers of Hemsleya penxianensis and their bioactive activity.

The tubers of the medicinal plant Hemsleya penxianensis (Cucurbitaceae) yielded 11 cucurbitane-type triterpenes Xuedanencins A-K by silica gel column, ODS column, and pre-HPLC techniques. Their structures were determined by spectroscopic analysis and examined alongside existing data from prior studies. Separated compounds were evaluated for cytotoxic activity against the Hela human cancer cell line and compounds 7 and 8 showed significant cytotoxicity with IC50 values at 1.82 and 2.45 µM, respectively.

New Cassane Diterpenoids from Caesalpinia sappan and their Antiplasmodial Activity.

One new cassane diterpene possessing an unusual N bridge between C-19 and C-20 named caesalsappanin R (1), as well as another new diterpene caesalsappanin S (2), were isolated from the seeds of Caesalpinia sappanwith methanol extract. Their structures were determined by spectroscopic analysis and examined alongside existing data from prior studies. Their biological activities were profiled by their antiplasmodial activity.

Folate-modified Annonaceous acetogenins nanosuspensions and their improved antitumor efficacy.

Annonaceous acetogenins (ACGs) are a large family of fatty acid derived natural products that are exclusively isolated from the Annonaceae species. Many members of this diverse family have a broad spectrum of biological activities, the most impressive of which is anticancer activity. However, their poor solubility and severe toxicity restrict their clinical application, and their complicated composition hinders their formulation and drug delivery. In this study, ß-cyclodextrin was modified with folic acid (FA) and then combined with soybean lecithin to prepare FA-modified ACGs nanosuspensions (FA-ACGs-NSps). The obtained FA-ACGs-NSps had a high drug payload of 57.59% and average particle size of 199.5 nm, and they exhibited sustained drug release within 142 hours. In comparison with ACGs-NSps, FA-ACGs-NSps showed significantly enhanced cytotoxicity and higher cell uptake toward folate receptor-positive 4T1 cell lines. An in vivo study demonstrated that FA-ACGs-NSps more effectively accumulated in tumors and enhanced the antitumor therapeutic efficacy with less toxicity in 4T1 tumor bearing mice. Therefore, FA-ACGs-NSps may be a promising drug delivery system for ACGs to improve their therapeutic window and may be suitable for clinical application to treat folate-positive tumors.

[Studies on chemical constituents of Clinopodium chinense].

Twenty-eight compounds were isolated and purified from Clinopodium chinense by Sephedax LH-20, ODS, MCI and preparative HPLC. Their structures were identified as apigenin (1), apigenin-7-O-ß-D-glucopyranoside (2), apigenin-7-O-ß-D-glucuronopyranoside (3), thellungianol (4), apigenin-7-O-ß-D-rutinoside (5), luteolin (6), luteolin-4'-O-ß-D-glucopyranoside (7), apigenin-7-O-ß-D-pyranglycuronate butyl ester (8), luteolin-7-O-ß-D-rutinoside (9), luteolin-7-O-ß-D-noehesperidoside (10), acacetin (11), acacetin-7-O-ß-D-glucuronopyranoside (12), buddleoside (13), naringenin (14), pruning (15), nairutin (16), isosakuranetin (17), isosakuranin (18), didymin (19), hesperidin (20), kaempferol (21), quercetin (22), kaempferol-3-O-α-L-rahmnoside (23), p-hydroxycinnamic acid (24), caffeic acid (25), cis-3-[2-[1-(3,4-dihydroxy-phenyl)-1 -hydroxymethyl]-1,3-ben-zodioxol-5-yl]-(E)-2-propenoic acid (26), mesaconic acid (27), gentisic acid 5-O-ß-D-(6'-salicylyl)-glucopyranoside (28). Among them, compounds 7, 9-10, 12, 23, 26-28 were isolated from the Clinopodium for the first time. The protective effects of compounds 1-6, 8-17 and 19 against H2O2-induced H9c2 cardiomyocyte injury were tested, compounds 15 exhibited significantly protective effects. Compared with the cell viability of (62.12±6.18)% in the model, pruning exhibited viabilities of (84.25±7.36)% at 25.0 mg•L⁻¹, respectively, using quercetin as a positive control [cell viability of (84.55±8.26)%, 20 mg•L⁻¹].

New cucurbitane triterpenoids with cytotoxic activities from Hemsleya penxianensis.

Seven new cucurbitane triterpenoids, Pengxianencins A-G (1-7) including one alkaloid, were isolated from the ethanol extract of the tubers of Hemsleya penxianensis. Their structures were elucidated on the basis of extensive spectroscopic data, including 1D and 2D NMR spectra as well as HR-ESI-MS. The evaluation of inhibition activity against human Hela, MCF-7, and A-549 cell lines showed that compounds 1, 4, 6, 7 have different levels of cytotoxic activities, with IC50 values ranging from 1.67 to 45.28µM.

Cassane diterpenes with oxygen bridge from the seeds of Caesalpinia sappan.

The seeds of the medicinal plant Caesalpinia sappan yielded fourteen cassane-type diterpenes, including six new rearranged ones named as caesalppans A-F (1-6). Their structures were elucidated by spectroscopic analysis and comparison with literature data. The isolated new compounds 1-6 possess lactone-type cassane diterpenoid skeleton with an oxygen bridge between C-19 and C-20, and were tested cytotoxic activity against four cancer cell lines using the MTT method.

Four new phenolic acid with unusual bicycle [2.2.2] octane moiety from Clerodendranthus spicatus and their anti-inflammatory activity.

Four new phenolic acids, clerodens A-D (1-4) possessing an unusual bicycle [2.2.2] octane moiety were isolated from the whole plants of Clerodendranthus spicatus. Their structures were elucidated by extensive spectroscopic methods, including NMR, MS, and ECD data. All isolates were evaluated for their anti-inflammatory activities on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7, and compound 4 showed significant inhibitory activities with IC50 value of 6.8 µM.

[Cassae-type diterpenes from seeds of Caesalpinia minax].

Fifteen cassaen-type diterpenes were isolated from the 95% ethanolic extract of the seeds of C. minax through various chromatographic techniques. Their structures were identified on the basis of spectroscopic data as pulcherralpin (1), caesalpinin ML (2), chamaetexane C (3), chamaetexane D (4), 6ß, 18-diacetoxycassan-13, 15-diene (5), neocaesalpin K (6), neocaesalpin MP (7), neocaesalpin M (8), neocaesalpin Q (9), neocaesalpin P (10), neocaesalpin R (11), caesaldekarin D (12), caesaldekarin A (13), caesaldekarin b (14), 3ß,6α-diacetoxyvouacapane (15). Among them, compounds 14, 9-11 were isolated from this plant for the first time.

Norcassane- and cassane-type furanoditerpenoids from the seeds of Caesalpinia sappan.

Three novel furanoditerpenoids, norcaesalpinin J (1) featuring an unusual 20-norcassane hydroperoxide and phangininoxys B (2) and C (3) possessing cassane hemiketal skeletons, were isolated from the seeds of Caesalpinia sappan. Their structures were elucidated by extensive spectroscopic methods. All isolates were evaluated for the cytotoxic activities on three human cancer cell lines.

Antimalarial diterpene alkaloids from the seeds of Caesalpinia minax.

Two new diterpene alkaloids, caesalminines A (1) and B (2), possessing a tetracyclic cassane-type furanoditerpenoid skeleton with γ-lactam ring, were isolated from the seeds of Caesalpinia minax. Their structures were determined by different spectroscopic methods and ECD calculation. The plausible biosynthetic pathway of caesalminines A and B was proposed. The anti-malarial activity of compounds 1 and 2 is presented with IC50 values of 0.42 and 0.79 µM, respectively.

Novel dinorcassane- and cassane-type diterpenes from the seeds of Caesalpinia minax.

Two novel diterpenes, norcaesalpinin I (1) featuring an unusual ring C-contracted dinorcassane and caesalpinin U (2) possessing a highly oxygenated furanocassane skeleton were isolated from the seeds of Caesalpinia minax. Their structures were determined by different spectroscopic methods. A plausible biosynthetic pathway of 1 was proposed. The cytotoxic activity of compounds 1 and 2 against HepG2 and HeLa human tumor cell lines was evaluated.

Two new degradative cassane-type diterpenes isolated from Caesalpinia minax.

Cassane-type diterpenes are main bioactive constituents of Caesalpinia minax HANCE. As a part of our ongoing chemical investigation of C. minax, two new degradative cassane-type diterpenes, named caesalpins I (1) and J (2), were isolated from the EtOAc extract of the seeds of C. minax. The structures were elucidated by means of spectroscopic analysis.