A rapid, sensitive, and selective precolumn derivatization method for the simultaneous determination of eight thiophenols using 3-(2-bromoacetamido)-<i>N</i>-(9-ethyl-9<i>H</i>)-carbazol as a labeling reagent by high-performance liquid chromatography with fluorescence detection has been developed. The labeling reagent reacted with thiophenols at 50°C for 50 min in aqueous acetonitrile in the presence of borate buffer (0.10 mol/L, pH 11.2) to give high yields of thiophenol derivatives. The derivatives were identified by online postcolumn mass spectrometry. The collision-induced dissociation spectra for thiophenol derivatives gave the corresponding specific fragment ions at <i>m/z</i> 251.3, 223.3, 210.9, 195.8, and 181.9. At the same time, derivatives exhibited intense fluorescence with an excitation maximum at λ<sub>ex</sub> = 276 nm and an emission maximum at λ<sub>em</sub> = 385 nm. Excellent linear responses were observed for all analytes over the range of 0.033-6.66 μmol/L with correlation coefficients of more than 0.9997. Detection limits were in the range of 0.94-5.77 μg/L with relative standard deviations of less than 4.54%. The feasibility of derivatization allowed the development of a rapid and highly sensitive method for the quantitative analysis of trace levels of thiophenols from some rubber products. The average recoveries (<i>n</i> = 3) were in the range of 87.21-101.12%.
Phytochemical studies on the whole herb of Sphaerophysa salsula has resulted in the discovery of one new 8-isopentenyl isoflavone derivative, named sphaerosin s2 (3-(8-(2-hydroxypropan-2-yl)-3,4-dihydro-2H-furo[2,3-h]chromen-3-yl)-2,6-dimethoxyphenol) (1), along with four know 8-isopentenyl isoflavone derivatives (2-5). Compounds (2, 4 and 5) were isolated for the first time from this species. Their structures were elucidated on the basis of ESI-MS, UV, IR, 1D NMR and 2D NMR data.
Though aboveground biomass (AGB) has an important contribution to the global carbon cycle, the information about storage and climatic effects of AGB is scare in Three-River Source Region (TRSR) shrub ecosystems. This study investigated AGB storage and its climatic controls in the TRSR alpine shrub ecosystems using data collected from 23 sites on the Tibetan Plateau from 2011 to 2013. We estimated the AGB storage (both shrub layer biomass and grass layer biomass) in the alpine shrubs as 37.49 Tg, with an average density of 1447.31 g m<sup>-2</sup>. Biomass was primarily accumulated in the shrub layer, which accounted for 92% of AGB, while the grass layer accounted for only 8%. AGB significantly increased with the mean annual temperature (<i>P</i> < 0.05). The effects of the mean annual precipitation on AGB were not significant. These results suggest that temperature, rather than precipitation, has significantly effects on of aboveground vegetation growth in the TRSR alpine shrub ecosystems. The actual and potential increase in AGB density was different due to global warming varies among different regions of the TRSR. We conclude that long-term monitoring of dynamic changes is necessary to improve the accuracy estimations of potential AGB carbon sequestration across the TRSR alpine shrub ecosystems.
An accurate and sensitive liquid chromatography-tandem mass spectrometry method was developed for the analysis of amino acids (isoleucine, leucine, valine, tyrosine, phenylalanine and tryptophan) in serum samples using a stable isotope labeling strategy. Amino acid samples and standards were, respectively, derivatized by 10-methyl-acridone-2-sulfonyl chloride (d0-MASC) and its deuterated counterpart d3-MASC to form isotopic pairs which co-eluted and were detected by an MS detector at the same time. Accurate internal standard-based quantification was thereby achieved without the use of any internal standard analogy. The labeling reaction of MASC with amino acids is fast, simple and robust. Besides, derivatization increased the molecular weight of amino acids, and therefore they were shifted out of the background noise which was often observed in low mass region. The instrument LODs were in the range of 1.0-2.5 nmol/L. Linearities calculated by comparing theoretical peak area ratios of d0-/d3-MASC derivatives with the experimental peak area ratios were excellent with correlation coefficients of >0.995. The proposed method was successfully applied to the analysis of amino acids in serum samples with high sensitivity and accuracy.
Seven oleanane-type triterpene saponin bisdesmosides, perennisaponins N-T (<i>1</i>-<i>7</i>), were newly isolated from a methanol extract of daisy, the flowers of <i>Bellis perennis</i> L. (Asteraceae). The structures were determined based on chemical and physicochemical data and confirmed using previously isolated related compounds as references. The isolates, including 13 previously reported perennisaponins A-M (<i>8</i>-<i>20</i>), exhibited anti-proliferative activities against human digestive tract carcinoma HSC-2, HSC-4, and MKN-45 cells. Among them, perennisaponin O (<i>2</i>, IC<sub>50</sub> = 11.2, 14.3, and 6.9 μM, respectively) showed relatively strong activities. The mechanism of action of <i>2</i> against HSC-2 was found to involve apoptotic cell death.
The adsorption mechanism of Cr(VI) onto different α-Fe2O3 crystal facets is chemisorption process through outer surface of doubly and triply coordinated hydroxyl groups.<br><br>Display Omitted<br>• 3D hierarchical α-Fe2O3 nanoparticles with different planes predominantly exposed were synthesized. • The Cr(VI) removal ability reach to 34.4 mg/g by flower-like α-Fe2O3 particles with (0 0 1) plane exposed. • The coordination between Cr(VI) and special doubly coordinated hydroxyl groups plays important role for adsorption.<br>Two kinds of 3D hierarchical α-Fe2O3 nanoparticles, flower-like structure with the (0 0 1) plane predominantly exposed on petals and urchin-like structure with nanorods grown along [0 0 1] direction, have been synthesized under the influence of glycerol by a facile hydrothermal method. It is proposed that the Fe(III)-glycerol micro-reaction units that selectively adsorb to (0 0 1) or other planes result in different morphologies. The adsorption of Cr(VI) from aqueous solution onto these α-Fe2O3 nanoparticles showed that the removal efficiency up to 98.5% and 88.8% in 25 mg/L Cr(VI) solution, and the adsorption capacity reaches to 34.4 mg/g and 26.0 mg/g without pH adjustment. The adsorption kinetic is well described by the pseudo-second-order model and the Cr(VI) adsorption on the adsorbent agrees well with the Langmuir model. Lower surface areas and more excellent adsorption property associates with the chemisorption of Cr(VI) onto α-Fe2O3 (0 0 1), which is achieved by coordination between Cr(VI) and doubly or triply coordinated hydroxyl groups on α-Fe2O3 surface.
Meconopsis horridula is one of alpine plants belonging to family Papaveraceae, mainly distributed in Himalaya Range area. M. horridula is a rare alpine flower, and is a kind of traditional Tibetan medicine, which has been included in more than 40 compound formulae, having efficacies of clearing away heat and alleviating pain, activating blood circulation to remove stasis, traditionally used for the treatment of fractures, injuries, and chest and back pains. Modern research shows that the whole plant of M. horridula contains alkaloids, flavonoids, and terpenes, and its pharmacological activities including antitumor, antivirus and myocardial protection etc. However, due to various factors, the current research of M.horridula still faces many challenges. This paper summaries herein a progress of MH on its ecological resources, traditional uses, and studies on chemical constituents and pharmacological effects, hopefully to provide a useful reference for the ecological protection and applications.
The aim of this study was to determine the inhibitory action of alantolactone, a gradient of traditional Chinese medicine Inulae Radix (Tu-Mu-Xiang), on herpes simplex virus 1 (HSV-1). African green monkey kidney cells (Vero cells) were infected with HSV-1 and the protective effects of alantolactone on Vero cells were examined. At concentrations of 10(-6), 10(-7), and 10(-8) g/mL, alantolactone did not have a marked harmful effect on the viability of Vero cells according to an MTT assay. Based on the cytopathic effect (CPE) and MTT assays, alantolactone at these concentrations exhibited antiviral action and protected cells from being damaged by HSV-1. Results indicated that alantolactone had potent anti-HSV-1 action and provided evidence for use of Inulae Radix in the treatment of HSV-1 infection.
Aim: To reinvestigate the chemical constituents of the ethanolic extract of Meconopsis quintuplinervia Regel which is a traditional Tibetan medicine used for treatments of hepatitis, tuberculosis etc..; Methods: The compounds were enriched by column chromatography techniques over silica gel, macro porous resin and Sephadex LH-20 absorbents, and finally purified by reverse phase preparative HPLC methods with isocratic mobile phase systems of methanol-H2O-acetic acid (500:500:1) and acetonitrile-H2O-acetic acid (200:800:1). Structural determination of the pure compounds were based on extensive analyses of modern spectroscopic methods including IR, MS, HRMS, 1D- and 2D-NMR spectra.; Results: Three alkaloids were obtained and their structures were elucidated as norsanguinarine (I), O-methylflavinantine (II) and 6-methoxy-17-methyl-2, 3-[methylenebis (oxy)]-morphin-5-en-7-one (III).; Conclusion: Norsanguinarine (I) was isolated from genus Meconopsis for the first time, and 6-methoxy-17-methyl-2,3-[methylenebis(oxy)]-morphin-5-en-7-one (III) is a new alkaloid named as meconoquintupline.;
Siwei Jianghuang Decoction Powder (SWJH) documented originally in the Four Medical Tantras-Blue Glaze exhibited beneficial effects on diabetic nephropathy (DN) via combined synergistically action of multiple formula components including Curcumae longae Rhizoma, Berberidis dictyophyllae Cortex, Phyllanthi Fructus and Tribuli Fructus. This study investigated the effects of SWJH on DN in db/db mice and possible underlying mechanisms. The ten weeks old db/db mice treated with SWJH by intra-gastric administration once a day for 8 weeks. After 8 weeks, body weight, water and food intake of mice were recorded. The level of fasting blood glucose (FBG) was measured. Serum creatinine (Scr), blood urea nitrogen (BUN), urine microalbumin (UMAlb), serum uric acid (UA) and urinary albumin excretion (UAE) were detected. An enzyme-linked immunosorbent assay was performed to test serum vascular endothelial growth factor (VEGF) and transforming growth factor-β1 (TGF-β1). Real-time PCR and Western blot analysis were used to test mRNA and protein expression of hypoxia inducible factor-1α (HIF-1α), VEGF and TGF-β1 in kidney tissue. SWJH treatment significantly reduced the levels of FBG, Scr, BUN, UMAlb, UA and UAE and retarded renal fibrosis. SWJH treatment further significantly reduced serum TGF-β1 level and downregulated the expression of HIF-1α, VEGF and TGF-β1 at both mRNA and protein levels. Principal component analysis and partial least squares regression and hierarchical cluster analysis demonstrated that SWJH treatment significantly ameliorated renal damage in DN mice. These consequences suggested that SWJH formulations were effective in the treatment of DN through regulating the HIF-1α, VEGF and TGF-β1 overexpression.
Jikan Mingmu Drops (JMD), a traditional Tibetan medicine containing six herbs, has been used to treat dry eye syndrome (DES) in individuals with diabetes mellitus. However, the activity of JMD ameliorates DES with diabetes mellitus has not been previously examined. The aim of the study is to investigate the molecular mechanism of JMD on db/db mice. The main chemical constituents of JMD were analyzed by high-performance liquid chromatography and gas chromatography-mass spectrometry. DES was then induced in db/db mice by applying 0.2% benzalkonium chloride to the ocular surface for 7 days. Eye drops containing JMD (0.25, 0.5, or 1 g/mL) or vehicle subsequently were administered three times daily for another 7 days, and the therapeutic effects were evaluated by phenol red thread tear and sodium fluorescein tests. Conjunctival specimens were subjected to hematoxylin and eosin staining and periodic acid-Schiff staining to examine pathological changes and number of goblet cells. ELISA was performed to assess the levels of various inflammatory cytokines. JMD contains hydroxysafflor yellow A, magnoflorine, jatrorrhizine hydrochloride, palmatine hydrochloride, berberine hydrochloride, gallic acid, ellagic acid, tauroursodeoxycholic acid, camphor, isoborneol, borneol, trans-cinnamic acid, and muscone. JMD treatment significantly increased the tear volume, decreased the corneal fluorescein staining score, restored the morphology and structure of conjunctival epithelial cells, and markedly downregulated the levels of interleukin (IL)-6, IL-17α, IL-1β, tumor necrosis factor-α, and vascular endothelial growth factor in the conjunctiva. Further data showed that these protective effects were accompanied by inhibition of inflammation in a dose-dependent manner. Amelioration of DES in db/db mice with diabetes mellitus by treatment with Tibetan medicine formula JMD maybe related to its anti-inflammatory effects.
<br>Display Omitted<br>• 4′-Carbonyl chloride rosamine was synthesized and used for NTs by UHPLC-MS/MS. • <b>In situ</b> UA-DDLLME was reported for the simultaneous determination of AANTs and MANTs. • The method was sensitive, selective, low matrix effect, speedy and eco-friendly. • A new analytical tool in diagnosis of AD-related disease.<br>Neurotransmitters (NTs) may play an important role in neurodegenerative disorders such as Alzheimer’s disease (AD). In order to investigate the potential links, a new simple, fast, accurate and sensitive analytical method, based on <b>in situ</b> ultrasound-assisted derivatization dispersive liquid-liquid microextraction (<b>in situ</b> UA-DDLLME) coupled with ultra high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS), has been developed and validated. The quantitation of amino acid neurotransmitters (AANTs) and monoamine neurotransmitters (MANTs) in urine of AD rats were performed in this work. The <b>in situ</b> UA-DDLLME procedure involved the rapid injection of the mixture of low toxic 4-bromoanisole (extractant) and acetonitrile (dispersant), which containing the new designed and synthesized 4′-carbonyl chloride rosamine (CCR) as derivatization reagent, into the aqueous phase of real sample and buffer. Under the selected conditions, the derivatization and microextraction of analytes were simultaneously completed within 1 min. Good linearity for each analyte (R > 0.992) was observed with low limit of detections (LODs, S/N > 3). Moreover, the proposed method was compared with direct detection or other reported methods, and the results showed that low matrix effects and good recoveries results were obtained in this work. Taken together, <b>in situ</b> UA-DDLLME coupled with UHPLC-MS/MS analysis was demonstrated to be a good method for sensitive, accurate and simultaneous monitoring of AANTs and MANTs. This method would be expected to be highly useful in AD diseases’ clinical diagnostics and may have potential value in monitoring the efficacy of treatment.
Dihuang powder (DHP) has been used in the traditional Chinese medicine for the treatment of diarrhea in some regions of China. But up to now, the anti-diarrheal activity of DHP haven't been performed with modern pharmacological technology. This study aims to investigate the quality control, the potential toxicity and anti-diarrheal activity of Dihuang powder in mice. High performance liquid chromatography (HPLC) and thin layer chromatography (TLC) were used to detect five active compounds in DHP for quality control, and the acute toxicity and sub-acute toxicity for 28-day oral administration of DHP were then evaluated. The anti-diarrheal activity was investigated using mouse model. Results showed that the levels of quercetin and berberine in DHP were 0.054 and 0.632 mg/g, respectively, and atractylodin, matrine, and patehouli aleohal were also detected in DHP. At the given doses, DHP was safe in terms of acute and sub-acute toxicity. Meanwhile, DHP exhibited strong anti-diarrheal effects as well as decreased gastrointestinal motility and the secretions induced by Sennae and castor oil in a dose-dependent manner. It could decrease the content of IL-1β, IL-6, and TNF-α in the small intestine, and improve the histopathological changes of small intestine and large intestine induced by Sennae. The antinociceptive and anti-inflammatory activities in vivo also were presented. Based on all of the results, we thought that DHP has anti-diarrheal activity, and could be used to treat diarrhea as well as alleviate the pain and inflammation induced by diarrhea. This study provides a theoretical basis for the clinical use of DHP and may assist in the development of new drugs for the treatment of diarrhea. The mechanism of the anti-diarrheal activity should be investigated in the future.
Ethnopharmacological relevance: The fruits of <b>Hippophae rhamnoides</b> L., <b>Lycium barbarum</b> L., <b>Lycium ruthenicum</b> Murr. and <b>Nitraria tangutorum</b> Bobr. are traditional medicinal food of Tibetans and used to alleviate fatigue caused by oxygen deficiency for thousands of years. The present study focused on exploiting natural polysaccharides with remarkable anti-fatigue activity from the four Qinghai-Tibet plateau characteristic berries.<br>Materials and methods: The fruits of <b>Hippophae rhamnoides</b>, <b>Lycium barbarum</b>, <b>Lycium ruthenicum</b> and <b>Nitraria tangutorum</b> were collected from Haixi national municipality of Mongol and Tibetan (N 36.32°, E98.11°; altitude: 3100 m), Qinghai, China. Their polysaccharides (HRWP, LBWP, LRWP and NTWP) were isolated by hot-water extraction, and purified by DEAE-Cellulose ion-exchange chromatography. The total carbohydrate, uronic acid, protein and starch contents of polysaccharides were determined by a spectrophotometric method. The molecular weight distributions of polysaccharides were determined by gel filtration chromatography. Their monosaccharide composition analysis was performed by the method of 1-phenyl-3-methyl-5-pyrazolone (PMP) pre-column derivatization and RP-HPLC analysis. HRWP, LBWP, LRWP and NTWP (50, 100 and 200 mg/kg) were orally administrated to mice once daily for 15 days, respectively. Anti-fatigue activity was assessed using the forced swim test (FST), and serum biochemical parameters were determined by an autoanalyzer and commercially available kits; the body and organs were also weighted.<br>Result: LBWP, LRWP and NTWP were mainly composed of glucans and some RG-I pectins, and HRWP was mainly composed of HG-type pectin and some glucans. All the four polysaccharides decreased immobility in the FST, and the effects of LBWP and NTWP were demonstrated in lower doses compared with HRWP and LRWP. There was no significant difference in liver and heart indices between non-treated and polysaccharide-treated mice, but the spleen indices were increased in LBWP and NTWP (200 mg/kg) group. Moreover, the FST-induced reduction in glucose (Glc), superoxide dismutase (SOD) and glutathione peroxidase (GPx) and increase in creatine phosphokinase (CK), lactic dehydrogenase (LDH), blood urea nitrogen (BUN), triglyceride (TG) and malondialdehyde (MDA) levels, all indicators of fatigue, were inhibited by HRWP, LBWP, LRWP and NTWP to a certain extent while the effects of LBWP and NTWP were much better than that of HRWP and LRWP at the same dosage.<br>Conclusion: Water-soluble polysaccharides HRWP, LBWP, LRWP and NTWP, from the fruits of four Tibetan plateau indigenous berry plants, significantly exhibited anti-fatigue activities for the first time, through triglyceride (TG) (or fat) mobilization during exercise and protecting corpuscular membrane by prevention of lipid oxidation via modifying several enzyme activities. Moreover, it is demonstrated that LBWP and NTWP are more potent than HRWP and LRWP, which were proposed to be applied in functional foods for anti-fatigue and antioxidant potential.<br><br>Display Omitted
Background: Swertia chirayita, has been commonly used under the name "Zang-yin-chen" for the treatment of liver infections, inflammation, abdominal pain, and bacterial infection in traditional Tibetan medicine. However, the bioactive components with anti-inflammatory activities and underlying mechanisms remain poorly evaluated.Study Design/methods: Repeated column chromatography yielded two main xanthones from petroleum ether (PE) and ethyl acetate fractions of whole plants of S. chirayita, and their structures were determined as bellidifolin (1) and swerchirin (2) on the basis of spectroscopic data and literature analysis. The anti-inflammatory activities and mechanisms of anti-inflammation of these two isolated xanthones were determined via enzyme-linked immunosorbent assay (ELISA) and western blot in lipopolysaccharide (LPS)-stimulated RAW 264.7 murine macrophages in vitro.Results: Anti-inflammation assay demonstrated that 1 and 2 inhibit the production of the pro-inflammatory cytokines interleukin-6 (IL-6) and TNF-α in LPS-stimulated RAW 264.7 macrophages. Xanthone 1 also potently inhibited the production of prostaglandin E2 (PGE2) by suppressing the protein expression of cyclooxygenase-2 (COX-2) in LPS-stimulated RAW 264.7 macrophages. Western blot showed that the phosphorylation of c-Jun N-terminal kinases (JNK), extracellular signal-regulated kinase (ERK), and p38 MAPKs were remarkably attenuated by 1 in a concentration-dependent manner. Particularly, Compound 1 suppressed the phosphorylation of the inhibitor κB kinase-β (IKK-β), Akt, and p65 subunit of nuclear factor-kappaB (NF-κB).Conclusion: The potent suppressive effects of 1 from S. chirayita on inflammatory mediators by blocking the expression of COX-2 and phosphorylation of Akt, IKK-β, MAPK and NF-κB, activation in LPS-stimulated macrophages suggest that 1 can be a preventive therapeutic candidate for the management of inflammatory-mediated immune disorders.
Yak butter is one of the most important foods for the Tibetan people. Of note, its production yields waste yak milk as a by-product. In this work, waste yak milk protein hydrolysates made via Pepsin hydrolysis were shown to have antimicrobial activity. Furthermore, an innovative method of magnetic liposome adsorption combined with reversed-phase high performance liquid chromatography (RP-HPLC) was developed to screen for and purify the antimicrobial peptides. Two antimicrobial peptides were obtained and their amino acid sequences were determined by N-sequencing, namely Arg-Val-Met-Phe-Lys-Trp-Ala and Lys-Val-Ile-Ser-Met-Ile. The antimicrobial activity spectra of Arg-Val-Met-Phe-Lys-Trp-Ala included Bacillus subtilis, Staphylcoccus aureus, Listeria innocua, Escherichia coli, Enterobacter cloacae and Salmonella paratyphi, while the Lys-Val-Ile-Ser-Met-Ile peptide shows not only bacterial growth inhibition but also of fungi. Haemolytic testing suggested that these two antimicrobial peptides could be considered to have no haemolytic effect at their minimum inhibitory concentrations (MICs).
Ethnopharmacological relevance Pterocephalus hookeri (C.B. Clarke) Höeck, one of the most popular Tibetan herbs, has been widely applied in Tibetan medicine prescriptions. Chemical investigations have led to the isolation of many bis-iridoids. However, the pharmacological activities of bis-iridoid constituents of this plant have never been reported before. Aim of the study This study evaluated the anti-inflammatory and analgesic activities of afraction of bis-iridoid constituents of P. hookeri (BCPH) in order to provide experimental evidence for its traditional use, such as for cold, flu, and rheumatoid arthritis. Materials and methods The analgesic effects of BCPH were investigated using the hot-plate test and acetic acid-induced writhing test. The anti-inflammatory activities were observed using the following models: carrageenin-induced edema of the hind paw of rats and xylene-induced ear edema in mice. The effects of dexamethasone administration were also studied. Results BCPH significantly increased the hot-platepain threshold and reduced acetic acid-induced writhing response in mice. Moreover, BCPH remarkably inhibited xylene-induced ear edema and reduced the carrageenin-induced rat paw edema perimeter. Conclusion The results reveal that BCPH has central, peripheral analgesic activities as well as anti-inflammatory effects, supporting the traditional application of this herb in treating various diseases associated with inflammation and pain.
The current study evaluated antioxidant activity of <i>Dracocephalum rupestre</i> Hance, characterized by the polyphenolic compounds in the ethyl acetate fraction (EAF) from <i>D. rupestre</i> and investigated the protective mechanisms of EAF in carbon tetrachloride (CCl₄)-induced hepatic injury. EAF showed the largest antioxidant capacity as demonstrated by DPPH, ABTS, OH, and FRAP assays (<i>p</i> ≤ .05). Using LC-MS, two polyphenolics, for example, rosmarinic acid, and eriodictyol were identified in EAF. Total phenol content of <i>D. rupestre</i> was correlated significantly with FRAP value (<i>r</i> = .999, <i>p</i> ≤ .001). The results also showed that EAF decreased serum ALT and AST activities compared with model group, as well as the histological findings. In addition, EAF remarkably decreased MDA and LDH levels in liver. This is the first time to reveal the hepatoprotective effect of EAF from <i>D. rupestre</i>, which may be developed as a new drug for treatment of liver injury in future.<br>Practical applications: <i>Dracocephalum rupestre</i> Hance is known as Chinese herbal medicine with pharmacological functions of antioxidant, anti-inflammatory and has been mainly used in the treatment of damp-heat, headache, fever, jaundice, hepatitis, liver toxicity, and other diseases. In order to detect the potential application of this plant, the antioxidant and hepatoprotective activities of <i>D. rupestre</i> were investigated. It was found that the ethyl acetate fraction (EAF) from <i>D. rupestre</i> displayed strong antioxidant activity. We also demonstrate that EAF could lessen CCl₄-induced acute liver injury in mice. Also, rosmarinic acid may play an important role in the antioxidant activity and hepatoprotective effect for EAF.
Tibetan medicinal plants have been used for more than 2 000 years. In order to find their differences in antioxidant activity, total phenolics and total flavonoids between "hot-nature" and "cold-nature" herbs, we investigated the antioxidant activities of 40 Tibetan herbs from Qinghai plateau, with 20 herbs in cold-nature and 20 herbs in hot-nature. Antioxidant capacities were evaluated by the following methods: scavenging ABTS•(+) (2, 2'azinobis-(3-ethylbenz-thiazoline-6-sulfonic acid), scavenging O2•(-), and Ferric-reducing antioxidant power (FRAP). The effects on inhibition of mitochondrion lipid peroxidation were determined by measuring the formation of TBARS (Thiobarbituric acid reactive substrates). Total phenolics and flavonoids were estimated by Folin-Ciocalteu and NaNO2-Al(NO3)3-NaOH colorimetric methods. Interestingly, the cold-nature herbs displayed higher antioxidant activities than the hot-nature ones, corresponding to nearly three-fold higher total phenolic contents in the cold-nature herbs. Moreover, the antioxidant activities correlated linearly with the levels of total phenolics for both cold-nature and hot-nature herbs, but only with the levels of total flavonoids for the hot-nature herbs. The results suggested that the phenolic compounds, but not the flavonoids, play the major role in antioxidant capacities of the cold-nature herbs. These findings could shed new lights on the study the theory of Tibetan medicine.
The content of bioactive phytochemicals, antioxidant activity and tyrosinase inhibitory activity of the hydroalcoholic extracts of <i>Rosa roxburghii</i> were determined. Yellow fruits of cultivated <i>R. roxburghii</i> showed the highest phenolic content (154.81 mg gallic acid g<sup>−1</sup>), and the green fruits of wild <i>R. roxburghii</i> showed higher content of flavonoid and triterpenoid. <i>Rosa roxburghii</i> fruits from different cultivars and maturity stages all demonstrated as good antioxidant agents and tyrosinase inhibitors, with IC50 value about twice of the positive standard in the DPPH assay and triple of the standard in the tyrosinase inhibitory activity assay. Nineteen compounds, mainly ellagic acids and its derivatives, flavonoids and their glycosides were identified by UPLC-Triple-TOF/MS analysis. As the first study of bioactive phytochemicals of <i>R. roxburghii</i> by UPLC-MS, the present research may provide valuable information for fulfilling the potential of <i>R. roxburghii</i> in the functional food area.<br>Antioxidant and tyrosinase inhibitory activity of <i>Rosa roxburghii</i> fruit and identification of main bioactive phytochemicals by UPLC-Triple-TOF/MS.
<br>Display Omitted<br> Two new phenolic acids (<b>1</b><b>2</b>) were isolated from the aerial parts of <b>Asterothamnus centrali-asiaticus</b>. Five knownphenolic acids (<b>3</b><b>7</b>) were also obtained from the title plant. <b>1</b><b>7</b> were evaluated for their anti-oxidant activity. <b>1</b><b>7</b> showed anti-oxidant activity with IC50 values ranging from 7.65 to 22.44 μg/mL.<br>Two new phenolic acids 2-hydroxy-5-[(6⿲-<b>O</b>-(<b>E</b>)-caffeoyl)-β-d-glucopyranosyl]-oxybenzoic acid (<b>1</b>) and 2-hydroxy-5-[(3⿲-<b>O</b>-(<b>E</b>)-caffeoyl)-β-d-glucopyranosyl]-oxybenzoic acid (<b>2</b>) were isolated from the aerial parts of <b>Asterothamnus centrali-asiaticus</b>, together with five known ones (<b>3</b>-<b>7</b>). Their structures were elucidated by extensive 1D and 2D NMR studies and HRESIMS investigations. The anti-oxidant activity of the isolates was evaluated through ABTS radical cation decolorization assay. The results showed that all of them exhibited anti-oxidant activity, and compound <b>7</b> was the most active compound with an IC50 value of 7.65 μg/mL.
Air pollution is a serious global health problem nowadays. So, it is an emergency to pay sufficient attention to treat and prevent the diseases caused by air pollution, especially respiratory disease and lung damage. Cladina rangiferina (L.) Nyl. is an edible lichen that has been used in medicinal diets to treat respiratory and other diseases for over 500 years. In this study, a water-soluble polysaccharide, CRWP-P, was obtained from C. rangiferina by hot-water extraction, freeze-thawing separation, and Fehling reagent purification. Structural analysis showed that CRWP-P is a linear α-(1 → 3),(1 → 4)-d-glucan without branches. Its Mw was determined to be 1.05 × 105 Da. Its (1,3)-α-d-glucopyranosyl: (1,4)-α-d-glucopyranosyl ratio is approximately 1:2. Antioxidant activity assay showed that C. rangiferina polysaccharides, especially CRWP-P, had appreciable DPPH radical-scavenging activity and reducing power. Notably, they could effectively decrease cell breakdown and ROS generation, inhibit lipid peroxidation, increase key antioxidase activity, and promote glutathione redox cycling in Pb2+-oxidative injured A549 alveolar epithelium cells. Overall, the results of this study indicated that C. rangiferina polysaccharides, especially CRWP-P, have the potential to be natural antioxidants for the treatment of lung oxidative damage induced by lead of air pollutants.
The young leaves and shoots of Sibiraea laevigata, known as "Liucha", are used as tea by Tibetans to improve digestion after meals. Long-term consumption of "Liucha" will cause weight loss. In present work, we reported on the isolation and NMR and chemical analysis-based elucidation of seven new sorbitol O-caffeic acid ester derivatives named sorbitol esters A-G (1-7) and eighteen known phenolic compounds from S. laevigata. All of the isolates were evaluated for their antioxidant and α-glucosidase inhibitory activities. Among them sorbitol ester A (1), sorbitol ester D (4), sorbitol ester F (6), sorbitol ester G (7), isoferulic acid (15), methyl caffeate (18), trans-p-hydroxycinnamic acid (19), and kaempferol 3-O-β-d-(6″-E-p-coumaroyl)-glucopyranoside (25) showed more potent α-glucosidase inhibitory activity than the clinical drug acarbose.