[Two new benzoyl-sesquiterpenes from Mesona chinensis].

Mesona chinensis is a common medicinal and edible plant in the Lingnan region of China, which has extensive pharmacological activity. However, the study of its chemical constituents is not sufficient. In this study, a variety of modern chromatographic separation techniques were used to isolate two compounds from 95% ethanol extract of the grass parts of M. chinensis. Their absolute configurations were determined by ultraviolet spectroscopy(UV), infrared spectroscopy(IR), high resolution mass spectrometry(HR-ESI-MS), 1D and 2D nuclear magnetic resonance(1D NMR and 2D NMR), and single-crystal X-ray diffraction(SC-XRD). Specifically, they were two new benzoyl-sesquiterpenes and named mesonanol A and mesonanol B, respectively. The results of the pharmacological activity evaluation showed that neither of the two new compounds showed obvious antiviral and anti-inflammatory activities.

Liquid chromatography-mass spectrometry-based strategy for systematic profiling of chemical components and associated quantitative analysis of quality markers in Qi-Wei-Tong-Bi oral liquid.

Qi-Wei-Tong-Bi oral liquid (QWTB), a famous Chinese medicine preparation composed of seven crude drugs has a good therapeutic effect on rheumatoid arthritis and is widely used in China. However, its chemical composition and quality control have not been comprehensively and systematically investigated. In this study, high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry was employed for its chemical profiling. As a result, 100 components were chemically characterized. Additionally, high-performance liquid chromatography coupled with a quadrupole linear ion trap mass spectrometry method was developed to simultaneously quantify nine bioactive components (hyperoside, ononin, quercetin, sinomenine, magnoflorine, gallic acid, protocatechuic acid, monotropein, and cyclo-(Pro-Tyr)) in multiple-reaction monitoring mode. After successful validation in terms of linearity, precision, repeatability, and recovery, the assay method was applied for the determination of 10 batches of QWTB. The results showed that QWTB was enriched in sinomenine and magnoflorine with the highest amount up to hundreds or even thousands of µg/mL, while quercetin, ononin, cyclo-(Pro-Tyr), and hyperoside were much lower with the lowest content below 10 µg/mL. This study work would help to reveal the chemical profiling and provide a valuable and reliable approach for quality evaluation and even pharmacodynamic material basis studies of QWTB.

Insoluble/soluble fraction ratio determines effects of dietary fiber on gut microbiota and serum metabolites in healthy mice.

Both soluble dietary fiber (SDF) and insoluble dietary fiber (IDF) play pivotal roles in maintaining gut microbiota homeostasis; whether the effects of the different ratios of IDF and SDF are consistent remains unclear. Consequently, we selected SDFs and IDFs from six representative foods (apple, celery, kale, black fungus, oats, and soybeans) and formulated nine dietary fiber recipes composed of IDF and SDF with a ratio from 1 : 9 to 9 : 1 (NDFR) to compare their impact on microbial effects with healthy mice. We discovered that NDFR treatment decreased the abundance of Proteobacteria and the ratio of Firmicutes/Bacteroidetes at the phylum level. The α diversity and relative richness of Parabacteroides and Prevotella at the genus level showed an upward trend along with the ratio of IDF increasing, while the relative abundance of Akkermansia at the genus level and the production of acetic acid and propionic acid exhibited an increased trend along with the ratio of SDF increasing. The relative abundance of Parabacteroides and Prevotella in the I9S1DF group (the ratio of IDF and SDF was 9 : 1) was 1.72 times and 5.92 times higher than that in the I1S9DF group (the ratio of IDF and SDF was 1 : 9), respectively. The relative abundance of Akkermansia in the I1S9DF group was 17.18 times higher than that in the I9S1DF group. Moreover, a high ratio of SDF (SDF reaches 60% or more) enriched the glycerophospholipid metabolism pathway; however, a high ratio of IDF (IDF reaches 80% or more) regulated the tricarboxylic acid cycle. These findings are helpful in the development of dietary fiber supplements based on gut microbiota and metabolites.

Secoiridoid glycosides from the fruits of Ligustrum lucidum and their in vitro anti-inflammatory activity.

Seven new secoiridoid glycosides (1-7), together with a known analogue (8), were isolated from the fruits of Ligustrum lucidum. Their structures with absolute configurations were determined by HR-ESI-MS, 1D and 2D NMR, and electronic circular dichroism (ECD) spectroscopic analysis, as well as biogenetic consideration. Compounds 1 and 2 are the first examples of secoiridoid glycoside dimers featuring a rare rearranged oleoside-type secoiridoid moiety, and compounds 3-7 represent a new class of oleoside-type secoiridoid glycosides with unusual stereochemistry at C-1 position. A plausible biosynthetic pathway for this group of unusual secoiridoid glycosides was also proposed herein. In addition, the isolates were evaluated for their in vitro anti-inflammatory activity, and all tested compounds exhibited modest inhibitory effects against nitric oxide (NO) production in lipopolysaccharide (LPS)-induced RAW264.7 macrophages.

A comprehensive review: Botany, phytochemistry, traditional uses, pharmacology, and toxicology of Spatholobus suberectus vine stems.

ETHNOPHARMACOLOGICAL RELEVANCE: Spatholobus suberectus vine stem (SSVS) is the dried lianoid stem of the leguminous plant, Spatholobus suberectus Dunn, which is mainly distributed in China and some Southeast Asian countries. Due to its notable effects of promoting blood circulation and tonifying blood, regulating menstruation and relieving pain, this phytomedicine has been used in traditional Chinese medicine for hundreds of years. AIM OF THE STUDY: This review is designed to provide a comprehensive profile of SSVS concerning its botany, traditional uses, phytochemistry, quality control, pharmacology, pharmacokinetics, and toxicology and attempts to provide a scientific basis and future directions for further research and development. MATERIALS AND METHODS: Related document information was collected with the help of databases such as the Web of Science, Science Direct, PubMed, China National Knowledge Infrastructure (CNKI) and Flora of China. RESULTS: SSVS is reported to be traditionally used to treat rheumatic arthralgia, numbness and paralysis, blood deficiency, irregular menstruation and other gynecological diseases. Botanical studies have revealed that there are some confusable varieties in some specific locations with a long history. Additionally, 145 chemical constituents have been isolated and identified from SSVS, including flavonoids, organic acids, terpenoids, lignans, and phenolic glycosides. Pharmacological studies have shown that SSVS has a variety of effects, such as nervous system regulation, and antioxidative, antitumor, antiviral, antidiabetic, and anti-inflammatory effects. However, in regard to the absorption-distribution-metabolism-elimination-toxicity (ADMET) of SSVS, few studies have been carried out, and few articles have been published. CONCLUSION: With a long history of traditional uses, a variety of bioactive phytochemicals and a wide range of definite pharmacological activities, SSVS is believed to have great potential in clinical applications and further research, development and exploitation. The precise action mechanisms, rational quality control and quality markers, and explicit ADMET routes should be highlighted in the future, which might provide effective help to safely, effectively and sustainably use this herbal medicine.

Anthraquinone Removal from Cassia obtusifolia Seed Water Extract Using Baking, Stir-Frying, and Adsorption Treatments: Effects on the Chemical Composition, Physicochemical Properties of Polysaccharides, and Antioxidant Activities of the Water Extract.

Safety issues of the controversial anthraquinones from Cassia obtusifolia seed water extracts (CWEs) limit its application. This work aimed to remove the anthraquinones of CWEs by baking treatment (BT), stir-frying treatment (ST), and adsorption treatment (AT). Effects of these treatments on the chemical composition, physicochemical properties of polysaccharides, and antioxidant activities of CWEs were analyzed and compared. Results indicated that AT exhibited the best removal effect on the total anthraquinone among the three treatments. After AT, the contents of rhein, emodin, aloe-emodin, and aurantio-obtusin of the CWE were below the limit of detection. In addition, AT increased the contents of neutral sugars in CWEs in comparison to BT and ST. None of the treatments had an obvious influence on the structural characteristics of polysaccharides. However, AT decreased the antioxidant activity of CWEs due to their lower anthraquinone content. In summary, AT was considered as an efficient and simple method to remove anthraquinones, while retaining the features of polysaccharides.

The effect of guar gum consumption on the lipid profile in type 2 diabetes mellitus: a systematic review and meta-analysis of randomized controlled trials.

Dyslipidemia is a common encounter in type 2 diabetes mellitus (T2DM) and the current strategies to manage it are still suboptimal. Subsequently, identifying newer molecules with lipid-lowering effects is necessary. A great deal of attention has been given in recent years to fiber supplements, e.g., guar gum. Thus, we screened and evaluated the quality of the evidence regarding the benefits of guar gum supplementation in T2DM and conducted a meta-analysis to assess the effects of this compound on serum lipids in T2DM. We conducted a comprehensive search in PubMed/Medline, Web of Science, Scopus, Google Scholar and Embase, from the inception of these databases until January 2021. In total, 11 papers were included based on the eligible criteria in our meta-analysis. The meta-analysis of the eligible trials demonstrated a significant reduction of total cholesterol (TC) (WMD: -20.32 mg/dL, 95% CI: -27.02, -13.62, P < 0.001) and low-density lipoprotein cholesterol (LDL-C) (WMD: -14.52 mg/dL, 95% CI: -20.69, -8.35, P < 0.001) following guar gum supplementation in T2DM patients. The subgroup analysis based on the dosage (g/day) of this compound revealed that ≥20 g/day of guar gum led to a notable decrease in triglyceride (TG) levels (WMD: -12.55 mg/dL, 95% CI: -23.72, -1.37, P = 0.02) versus < 20 g/day (WMD: -1.84 mg/dL, 95% CI: -32.18, 28.49, P = 0.90). Guar gum supplementation had no effects on high-density lipoprotein cholesterol (HDL-C) (WMD: 0.66 mg/dL, 95% CI: -0.95, 2.28, P = 0.42). Guar gum consumption has lipid-lowering effects when administered to patients with type 2 diabetes mellitus and it is particularly able to reduce TC, LDL-C and TG levels. Further research is however needed to confirm our findings.

Tea polyphenol and epigallocatechin gallate ameliorate hyperlipidemia via regulating liver metabolism and remodeling gut microbiota.

Hyperlipidemia can directly cause metabolic diseases that seriously endanger disorder and metabolism and gut health. Tea polyphenol (TP) and epigallocatechin gallate (EGCG) was found to improve blood lipid levels and gut microbiota. This study aimed to investigate the effects of TP and EGCG on alleviating hyperlipidemia and liver fat accumulation with physiology, genomics, and metabolomics. Results showed that both TP and EGCG reduced body weight, and TP showed advantages in the decrease of serum cholesterol and triglycerides in hyperlipidemic rats induced by the high-fat diet. Moreover, EGCG may protect liver function via reducing the glycerophospholipids increased by high-fat diet intervention. TP remodeled the gut microbiota composition and enriched the abundance of beneficial bacteria (Bacteroides, Faecalibacterium, Parabacteroides, Akkermansia), and EGCG may improve gut health via promoting the acid-producing bacteria (such as Butyricimonas, Desulfovibrio). The above results provided new insights into the hypolipidemic mechanism of TP and EGCG.

Structural characteristic of pectin-glucuronoxylan complex from Dolichos lablab L. hull.

Polysaccharides are important constituents in Dolichos lablab hull. Herein, pectin-glucuronoxylan complex from D. lablab hull designated as DLHP-3 (D. lablab hull polysaccharide,) was prepared by ion exchange and gel permeation chromatography, and further characterized by acid degradation and enzymatic hydrolysis, methylation combined with GC-MS, NMR and MALDI-TOF-MS analysis. Both of pectin and glucuronoxylan regions were found in DLHP-3. The glucuronoxylan region consisted of a →4)-ß-Xylp-(1→ backbone with branches of α-GlcpA-(1→ substituted at O-2 site, and the ratio of xylose to glucuronic acid was about 5:1. Acetyl groups were mainly attached to O-3 site of →2,4)-ß-Xylp-(1→ residues. The main chain of pectin region could be represented by →4)-α-GalpA-(1→4)-α-GalpA-(1→ and →2)-α-Rhap-(1→4)-α-GalpA-(1→ with partial methyl-esterification. The side chains were deduced to embrace arabinan and arabinogalactan linked to rhamnogalacturonan-I region. Pectin was probably covalently bound to glucuronoxylan. Our findings uncovered the molecular structure of pectin-glucuronoxylan complex from D. lablab hull.

Stilbenes from the leaves of Cajanus cajan and their in vitro anti-inflammatory activities.

Eighteen stilbenes (1-18), including six previously undescribed ones (1-6), with diverse modification patterns were isolated from the leaves of edible and medicinal plant Cajanus cajan. Among the new isolates, compounds 1-3 were initially obtained as three racemic mixtures, which were further resolved into three pairs of optically pure enantiomers, respectively, by chiral HPLC. Besides, compounds 8, 10, 11, and 18 were obtained from C. cajan for the first time. The chemical structures and absolute configurations of the new stilbenes were elucidated unambiguously on the basis of extensive spectroscopic analyses, single crystal X-ray crystallographic study, and quantum chemical electronic circular dichroism (ECD) calculations. In addition, the in vitro anti-inflammatory activities of all isolated stilbenes were evaluated. Compounds 2, 9, 10, 11, and 14 exerted moderate suppression of nitric oxide (NO) secretion in lipopolysaccharide (LPS)-induced RAW264.7 cells without exhibiting substantial cytotoxicity.

Angiogenesis-Inhibitory Piperidine Alkaloids from the Leaves of Microcos paniculata.

Eight new 2,6-disubstituted piperidin-3-ol alkaloids (1-8), featuring a C10 unsaturated alkyl side chain, together with three previously reported analogues (9-11) were isolated from the leaves of medicinal plant Microcos paniculata. Their structures and absolute configurations were elucidated unambiguously by means of 1D and 2D NMR spectroscopic data analysis, modified Mosher's method, Snatzke's method, and quantum chemical electronic circular dichroism (ECD) calculations, as well as single-crystal X-ray crystallography. The isolates were evaluated for their antiangiogenic effects on human umbilical vein endothelial cells (HUVECs). Compound 2 displayed an inhibitory effect on tube formation of HUVECs in a concentration-dependent manner.

Efficient enrichment of total flavonoids from kale (Brassica oleracea L. var. acephala L.) extracts by NKA-9 resin and antioxidant activities of flavonoids extract in vitro.

This work established an effective method for kale flavonoids enrichment by resins. Resin screening, adsorption kinetics and isotherms, dynamic adsorption and desorption tests were conducted to optimize the appropriate resins and enrichment conditions. The results showed that NKA-9 was the optimum resin. The best adsorption conditions were 0.2 mg/mL flavonoids concentration, 12.5 bed volume (BV) sample volume and 2 BV/h adsorption rate. The desorption conditions were 3 BV of 80% ethanol at 2 BV/h elution rate. Under these conditions, the product purity was 31.16%. The purified flavonoids extract was mainly comprised of Kaempferol-3-O-sophoroside-7-O-diglucoside, Kaempferol-3,7,4'-O-d-triglucoside, Kaempferol-3-O-feruloyl-sophoroside-7-O-d-glucoside, and Kaempferol-3-O-sinapoyl-sophoroside. Moreover, it presented higher scavenging ability against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and hydroxyl (OH) radical than crude extract. In conclusion, kale flavonoids can be well concentrated by NKA-9 resin and the purified flavonoids extract has good antioxidant activity which can be potentially applied in food, cosmetic or pharmacy industries.

Quassinoids from the Roots of Eurycoma longifolia and Their Anti-Proliferation Activities.

A phytochemical investigation on the roots of medicinal plant Eurycoma longifolia resulted in the isolation of 10 new highly oxygenated C20 quassinoids longifolactones G‒P (1-10), along with four known ones (11-14). Their chemical structures and absolute configurations were unambiguously elucidated on the basis of comprehensive spectroscopic analysis and X-ray crystallographic data. Notably, compound 1 is a rare pentacyclic C20 quassinoid featuring a densely functionalized 2,5-dioxatricyclo[5.2.2.04,8]undecane core. Compound 4 represents the first example of quassinoids containing a 14,15-epoxy functionality, and 7 features an unusual α-oriented hydroxyl group at C-14. All isolated compounds were evaluated for their anti-proliferation activities on human leukemia cells. Among the isolates, compounds 5, 12, 13, and 14 potently inhibited the in vitro proliferation of K562 and HL-60 cells with IC50 values ranging from 2.90 to 8.20 µM.

Protective Effects of Total Flavonoids from Lysimachia christinae on Calcium Oxalate-Induced Oxidative Stress in a Renal Cell Line and Renal Tissue.

Oxidative stress (OS) in renal tubular epithelial cells (RTECs) is induced by calcium oxalate (CaOx) stones and plays an important role in the pathology of CaOx nephrolithiasis. The nuclear factor-E2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway is an important endogenous antioxidant pathway. Flavonoids are compounds with 2-phenylchromone as the basic mother nucleus and are natural antioxidant components of Lysimachia christinae. Our previous studies demonstrated that the total flavonoids from L. christinae (TFL) reduced calcium and oxalic acid concentrations in urine, thus inhibiting CaOx stone formation. We also showed that TFL can reduce OS in renal tissue. However, whether TFL inhibit the formation of CaOx stones through the Nrf2/ARE pathway requires further investigation. Here, we found that TFL protected against injury to a renal cell line and renal tissue, reduced CaOx-induced OS in renal tissue, and reduced CaOx crystal formation. In addition, TFL significantly increased nuclear Nrf2 and the expression of the downstream antioxidant genes heme oxygenase 1 (HO-1) and NAD(P)H quinone oxidoreductase 1 (NQO-1). Furthermore, TFL increased superoxide dismutase (SOD) activity and decreased the malondialdehyde (MDA) content, thereby alleviating OS in RTECs. Silencing Nrf2 expression blocked the protective effect of TFL on CaOx-induced OS. Taken together, our findings indicate that TFL reduce CaOx-induced OS in renal tissue by activating the Nrf2/ARE pathway.

3'-Oxo-tabernaelegantine A (OTNA) selectively relaxes pulmonary arteries by inhibiting AhR.

BACKGROUND: Pulmonary arterial hypertension (PAH), characterized by pulmonary artery constriction and vascular remodeling, has a high mortality rate. New drugs for the treatment of PAH urgently need to be developed. PURPOSE: This study was designed to investigate the vasorelaxant activity of OTNA in isolated pulmonary arteries, and explore its molecular mechanism. METHODS: Pulmonary arteries and thoracic aortas were isolated from mice, and vascular tone was tested with a Wire Myograph System. Nitric oxide levels were determined with DAF-FM DA and DAX-J2™ Red. Cellular thermal shift assays, microscale thermophoresis, and molecular docking were used to identify the interaction between OTNA and aryl hydrocarbon receptor (AhR). The levels of PI3K, p-PI3K, Akt, p-Akt, eNOS, p-eNOS, and AhR were analyzed by Western blotting. RESULTS: OTNA selectively relaxed the isolated pulmonary artery rings in an endothelium-dependent manner. Mechanistic study showed that OTNA induced NO production through activation of the PI3K/Akt/eNOS pathway in endothelial cells. Furthermore, we also found that OTNA directly bound to AhR and activated the PI3K/Akt/eNOS pathway to dilate pulmonary arteries by inhibiting AhR. CONCLUSIONS: OTNA relaxes pulmonary arteries by antagonizing AhR. This study provides a new natural antagonist of AhR as a promising lead compound for PAH treatment.

All-trans retinoic acid plus high-dose dexamethasone as first-line treatment for patients with newly diagnosed immune thrombocytopenia: a multicentre, open-label, randomised, controlled, phase 2 trial.

BACKGROUND: High-dose dexamethasone is the standard initial treatment for patients with immune thrombocytopenia, but many patients still relapse and require further treatments. All-trans retinoic acid has been shown to exert immunomodulatory effects and promote thrombopoiesis, and so we aimed to assess the activity and safety of all-trans retinoic acid plus high-dose dexamethasone as a first-line treatment for newly diagnosed patients with immune thrombocytopenia. METHODS: This multicentre, open-label, randomised, controlled, phase 2 trial was done at six different tertiary medical centres in China. Eligible participants were adults (aged >18 years) with treatment-naive, newly diagnosed, primary immune thrombocytopenia who had either a platelet count of less than 30 × 109 platelets per L or a platelet count of less than 50 × 109 platelets per L and clinically significant bleeding. We randomly assigned (1:1) participants to receive either all-trans retinoic acid (10 mg orally twice daily for 12 weeks) plus high-dose dexamethasone (40 mg/day intravenously for 4 consecutive days) or high-dose dexamethasone alone using a central, web-based randomisation system. If patients did not respond by day 14, the 4-day course of dexamethasone was repeated. The primary endpoint was 6-month sustained response, defined as the maintenance of a platelet count of at least 30 × 109 platelets per L and at least 2-times higher than the baseline count and the absence of bleeding, with no need for rescue medication at this time. The primary endpoint was analysed by intention-to-treat and safety was assessed in all participants who received at least one dose of the study drug. This trial is registered with ClinicalTrials.gov, NCT04217148, and is now completed. FINDINGS: Between Jan 1, 2020, and June 30, 2020, 132 patients were randomly assigned to either all-trans retinoic acid plus high-dose dexamethasone (n=66) or high-dose dexamethasone alone (n=66). Three patients did not receive their allocated treatment, leaving 129 in the safety analysis set. At 6 months, a significantly higher proportion of participants in the all-trans retinoic acid plus high-dose dexamethasone group (45 [68%] of 66) than in the high-dose dexamethasone monotherapy group (27 [41%] of 66) had a sustained response (OR 3·095, 95% CI 1·516-6·318; p=0·0017). The most common adverse events were dry skin (31 [48%] of 64 patients), headaches (12 [19%]), and insomnia (12 [19%]) in the combination group, and insomnia (ten [15%] of 65 patients) and anxiety or mood disorders (eight [12%]) in the monotherapy group. Both treatments were well tolerated and no grade 4 or worse adverse events occurred. There were no treatment-related deaths. INTERPRETATION: The combination of all-trans retinoic acid and high-dose dexamethasone was safe and active in newly diagnosed patients with primary immune thrombocytopenia, providing a sustained response. This regimen represents a potential first-line treatment in this setting, but further studies are needed to validate its efficacy and safety. FUNDING: The Beijing Municipal Science and Technology Commission, the National Natural Science Foundation of China, the Beijing Natural Science Foundation, the National Key Research and Development Program of China, and the Foundation for Innovative Research Groups of the National Natural Science Foundation of China.

[Triterpenoids from leaves of Ilex guayusa].

The chemical constituents from the leaves of Ilex guayusa were investigated. Sixteen triterpenoids were isolated from the 95% ethanol extract of dried leaves of I. guayusa by silica gel, Sephadex LH-20, and ODS column chromatographies and semi-prepa-rative HPLC. Those triterpenoids were identified by NMR, HR-MS, and literature analysis: 3ß-hydroxy-11α,12α-epoxy-24-nor-urs-4(23)-ene-28,13ß-olide(1), 3ß-hydroxy-24-nor-4(23),12-oleanadien-28-methyl ester(2), oleanolic acid(3), 3ß,28-dihydroxy-12-oleanene(4), 2α,3ß-dihydroxy-11α,12α-epoxy-24-'nor-olean-4(23)-ene-28,13ß-olide(5), ursolic acid(6), 3ß,23-dihydroxy ursolic acid(7), 3ß,28-dihydroxy-12-ursene(8), 3ß-28-nor-urs-12-ene-3,17-diol(9), 3ß-hydroxyurs-11-ene-28,13ß-olide(10), 13ß,28-epoxy-3ß-hydroxy-11-ursene(11), 3ß-hydroxy-28,28-dimethoxy-12-ursene(12), 3ß-hydroxy-24-nor-urs-4(23),12-dien-28-oic acid(13), 3ß-hydroxy-24-nor-urs-4(23),12-dien-28-methyl ester(14), 2α,3ß-dihydroxy-11α,12α-epoxy-24-nor-urs-4(23)-ene-28,13ß-olide(15) and 2α,3ß-dihydroxy-11α,12α-epoxy-24-nor-urs-4(23),20(30)-dien-28,13ß-olide(16). Compounds 1-2 were new compounds, and compounds 4-5, 7 and 9-16 were isolated from I. guayusa for the first time.

[Two new pyranonaphthoquinones from Mansoa alliacea].

Mansoa alliacea,commonly known as garlic vine,is native to the tropical rain forests of South America and widely cultivated in South China. As a popular folk medicine with various biological activities,however,this plant remains to be fully elucidated in terms of its phytochemical constituents. In this study,two new pyranonaphthoquinones were isolated from the 95% ethanol extract of the leaves and twigs of M. alliacea by various chromatographic approaches including silica gel,octadecyl silica( ODS),Sephadex LH-20,and preparative high-performance liquid chromatography( PHPLC). Their structures were determined to be 8,9-dimethoxy-α-lapachone( 1) and 7-hydroxy-8,9-dimethoxy-α-lapachone( 2) by comprehensive spectroscopic analyses and therefore respectively named as mansonin A( 1) and mansonin B( 2).

Phloroglucinol-derived lipids from the leaves of Syzygium cumini and their neuroprotective activities.

Based on the typical HPLC-UV-MS profiles and characteristic 1H NMR signals, twelve new phloroglucinol-derived lipids (1-12), featuring a long linear aliphatic side chain, together with three known ones (13-15) were isolated from the ethanol extract of the leaves of Syzygium cumini. Their structures were elucidated on the basis of extensive NMR spectroscopic analyses and mass spectrometric data. Compounds 1-5 characterize an enolizable ß,ß'-tricarbonyl motif with a cyclohexa-3,5-dien-1-one core that is hitherto undescribed in phloroglucinol-derived lipids. Compounds 4 and 10-12 are novel phloroglucinol-derived lipids containing an uncommon methylene interrupted trans double bond in their polyunsaturated aliphatic side chains. A polyketide biogenetic pathway for those phloroglucinol-derived lipids was also proposed. In addition, the isolates were evaluated for their neuroprotective activities against oxygen-glucose deprivation and re­oxygenation (OGD/R)-induced Neuro-2a cell injury. Notably, compounds 1, 5, and 10-12 significantly improved viability of Neuro-2a cells after OGD/R damage.

Rhodomentosones A and B: Two Pairs of Enantiomeric Phloroglucinol Trimers from Rhodomyrtus tomentosa and Their Asymmetric Biomimetic Synthesis.

Rhodomentosones A and B (1 and 2), two pairs of novel enantiomeric phloroglucinol trimers featuring a unique 6/5/5/6/5/5/6-fused ring system were isolated from Rhodomyrtus tomentosa. Their structures with absolute configurations were elucidated by NMR spectroscopy, X-ray crystallography, and ECD calculation. The bioinspired syntheses of 1 and 2 were achieved in six steps featuring an organocatalytic asymmetric dehydroxylation/Michael addition/Kornblum-DeLaMare rearrangement/ketalization cascade reaction. Compounds 1 and 2 exhibited promising antiviral activities against respiratory syncytial virus (RSV).