Structures and bioactivities of seven flavonoids from Osmanthus fragrans 'Jinqiu' essential oil extraction residues.

Osmanthus fragrans are well-known for their fragrance, but it is wasteful if to discard O. fragrans flower after extracting their essential oils. In this paper, we found that O. fragrans flower residues were rich in flavonoids. Six flavonoids and one phenylethanoid glycoside were isolated from the ethanol extract of O. fragrans flower residues, identified as quercetin (1), rutin (2), verbascoside (3), genistin (4), kaempferol (5), isorhamnetin (6) and naringin (7). In bioactivity study, kaempferol (IC50 = 1.43 µg/mL) showed the best anti-inflammatory activity. Isorhamnetin, quercetin, kaempferol, verbascoside and rutin (the values of IC50 were 18.30, 11.05, 16.88, 20.21 and 22.76 µg/mL, respectively) showed excellent DPPH free radical scavenging activity. Verbascoside performed relatively well at inhibiting the growth of both CT26 colonic carcinoma cells (IC50 = 46.87 µg/mL) and HepG2 hepatocarcinoma cells (IC50 = 30.58 µg/mL). In addition, quercetin and kaempferol showed strong anti-proliferation activity against HepG2 cells.

Two new compounds from the leaves of Indocalamus latifolius.

Two new compounds, erythro-syringylglycerol-9-O-trans-4-hydroxycinnamate 7-O-ß-d-glucopyranoside (1) and indocalatin A (2), together with three known ones, 5,7,3'-trihydroxy-6-C-ß-d-digitoxopyranosyl-4'-O-ß-d-glucopyranosyl flavonoid (3), 5,4'-dihydroxy-3',5'-dimethoxy-7-O-[ß-d-apiose-(1→2)]-ß-d-glucopyranosyl flavonoid (4), and tricin-6-C-ß-boivinopyranosyl-8-C-ß-glucopyranoside (5), were isolated from the 95% EtOH extract of Indocalamus latifolius leaves. Their molecular structures were determined by UV, IR, HRESIMS, CD, and 1D and 2D NMR data analyses.

Chemical Constituents and Antibacterial Properties of Indocalamus latifolius McClure Leaves, the Packaging Material for "Zongzi".

The glutinous rice dumpling named "Zongzi" in Chinese is a type of traditional food that is popular in East Asian countries. "Zongzi" is made of glutinous rice and wrapped in the leaves of Indocalamus latifolius McClure as the packaging material. Four new compounds, latifoliusine A (2), (7S,8R) syringylglycerol-8-O-4'-sinapyl ether 4-O-ß-d-glucopyranoside (7), (7S,8S) syringylglycerol-8-O-4'-sinapyl ether 7-O-ß-d-glucopyranoside (8), and (7R,8S) syringylglycerol-8-O-4'-sinapyl ether 7-O-ß-d-glucopyranoside (10), along with six known compounds (1, 3-6 and 9) were isolated from I. latifolius McClure leaves. The structures and relative configurations of the compounds were determined by detailed spectroscopic analysis, high-resolution electrospray ionization mass spectroscopy (HRESIMS), heteronuclear single quantum correlation (HSQC), heteronuclear multiple bond correlation (HMBC), nuclear overhauser enhancement (NOE) and circular dichroism (CD). All of the isolated compounds were screened for their antibacterial activities in vitro. The results indicated that apigenin 6-C-α-l-arabinopyranosyl-8-C-ß-d-glucopyranoside (5) and apigenin 7-O,8-C-di-glucopyranoside (6) have antibacterial activities against four bacterial strains (Staphylococcus aureus, Bacillus thuringiensis, Escherichia coli and Pseudomonas solanacearum).

Enantiomeric determination of four diastereoisomeric oxyneolignans from Bambusa tuldoides Munro.

INTRODUCTION: Bambusa tuldoides Munro, a bamboo species, is used as a health food, dietary supplement and folk medicine in China, and produces lignans that can be used to supplement other natural sources. OBJECTIVE: To simultaneously separate eight stereoisomers of a particular type of oxyneolignan by chiral chromatography. METHODS: Ninety-five per cent ethanol extracts of B. tuldoides Munro were analysed using HPLC/UV with a chiral column. The structures and configurations of isolated compounds were elucidated using NMR and circular dichroism (CD). RESULTS: Four diastereoisomers were characterised and given the names oxyneolignans A, B, C and D. Furthermore, each oxyneolignan occurred as a pair of enantiomers. The oxyneolignans A-D consisted of the erythro-diastereoisomer of oxyneolignan at C7 and C8. CONCLUSION: The chiral chromatography combined with the analysis techniques of NMR and CD reported here were reliable methods for discovering and separating the enantiomers.

[Simultaneous determination of four flavone C-glycosides in Phyllostachys edulis leaves by high-performance liquid chromatography with ultraviolet spectrometry].

High-performance liquid chromatography with ultraviolet spectrometer (HPLC-UV) was used to simultaneously detect the four flavone C-glycosides, i. e. orientin, isoorientin, vitexin and isovitexin. Analytes were separated with Waters XTerra MS C18 column (250 mm x 4.6 mm, 5 µm) using acetonitrile and 0.5% (φ) formic acid as mobile phase. The flow rate was set at 1.0 mL · min(-1) with the column temperature at 30 °C, and the detection wavelength was 360 nm. The calibration curve was linear over the concentration range of 0.1-10.0 mg · L(-1) for the mixed standard solution. Analytes were separated in 22 minutes, and the relative standard deviation values were all above 0.999. LOD values of standards were found to be between 0.03 and 0.07 mg · L(-1), and LOQ values were in the range of 0.04-0.08 mg · L(-1). After comparing the spectra (240-400 nm) of four flavone C-glycosides in mixed standards and the final product purified by macroporous resin, respectively, the curve shape and characteristic ultraviolet absorption wavelength of each flavone C-glycoside including orientin, isoorientin, vitexin and isovitexin were fitted well. The bamboo leaves sample was extracted by ethanol under reflux, and then partitioned with water and petroleum ether. The aqueous phase was added onto macroporous resin (AB-8), and the fraction of ethanol-water (40%, φ) was concentrated. It was found that the contents of orientin, isoorientin, vitexin and isovitexin relative to the fraction of ethanol- water were 13.73, 49.68, 7.85 and 30.70 mg · g(-1), respectively. In addition, the average recovery of the four flavone C-glycosides ranged from 34.90% to 87.64% with RSD values from 0.41% to 10.83%. The results showed that bamboo leaves sample had good stability and repeatability. The new method was used to analyze the four flavone C-glycosides quickly and provide quality control for commercial products.

Two new compounds from the dry leaves of Pleioblastus amarus (Keng) keng f.

Two new compounds, xylitol 1-O-(6'-O-p-hydroxylbenzoyl)-glucopyranoside (1) and bambulignan B (2), together with three known ones gastrodin (3), glucovanillin (4), and rel-(7S,7'R,8R,8'S)-4,4'-dihydroxy-3,3',5,5'-tetramethoxy-7,7'-epoxyligna-9,9'-diol-9(or)9'-O-ß-glucopyranoside (5), were isolated from the 95% EtOH extract of the dry leaves of Pleioblastus amarus (Keng) keng f. Their structures were determined by UV, IR, HR-ESI-MS, CD, and 1D and 2D NMR data analyses as well as GC experiments.

Isolation and identification of lignans from Caulis Bambusae in Taenia with antioxidant properties.

Caulis Bambusae in Taenia is a medicinal preparation from Bambusa tuldoides Munro consisting of skinless slices of the stem (bamboo shavings) and used as a traditional health food in tea, wine, and soup in Asia. Three novel lignans, (-)-7'-epi-lyoniresinol 4,9'-di-O-ß-D-glucopyranoside (7), (-)-lyoniresinol 4,9'-di-O-ß-D-glucopyranoside (8), bambulignan A (10), and seven known lignan compounds (1-6 and 9) were isolated from Caulis Bambusae in Taenia. The structures of the lignans were determined by detailed spectroscopic analysis (HRESIMS, HSQC, HMBC, NOE). All the isolated lignans were tested for antioxidant activities by DPPH and FARP assays. The results showed that the compounds (+)-lyoniresinol 9'-O-ß-D-glucopyranoside (1) and (-)-7'-epi-lyoniresinol 9'-O-ß-D- glucopyranoside (9) have strong free radical scavenging activity and reducing power.

TLC screening for antioxidant activity of extracts from fifteen bamboo species and identification of antioxidant flavone glycosides from leaves of Bambusa. textilis McClure.

Interest in the antioxidant activity of bamboo leaves is growing. To discover new sources of natural antioxidants, a TLC bioautography method combined with a new image processing method was developed to evaluate the antioxidant activity of leaf extracts from 15 different species of bamboo. The results showed that the methanolic extract of Bambusa. textilis McClure possessed the highest antioxidant activity among the selected bamboo species. To rapidly identify the antioxidant compounds, the crude extract of B. textilis McClure was analysed by HPLC-UV, and HPLC-micro-fractionation of the extract was carried out. Based on TLC bioautography-guided fractionation, three antioxidant fractions were isolated from B. textilis McClure by preparative chromatography. These three antioxidant compounds were identified as isoorientin 4''-O ß-D-xylopyranoside, isoorientin 2''-O-α-L-rhamnoside and isoorientin according to their UV, MS, and NMR data. The proposed TLC screening method could therefore be an easy way to evaluate the antioxidant activity of bamboo leaves, and the results achieved should prove very helpful for promoting their utilization, as B. textilis McClure can be considered a promising plant source of natural antioxidants.

Screening and analysis of the potential bioactive components in rabbit plasma after oral administration of hot-water extracts from leaves of Bambusa textilis McClure.

Bambusa textilis McClure is a traditional Chinese medicinal plant belonging to the Bambusoideae subfamily and used to treat chronic fever and infectious diseases. To investigate the bioactive compounds absorbed in the rabbit blood after oral administration of hot-water extracts from the leaves of B. textilis McClure, a validated chromatographic fingerprint method was established using LC-Q-TOF-MS. Twenty compounds in bamboo leaves and three potential bioactive compounds in rabbit plasma were detected. Of the twenty detected compounds in vitro, fifteen of which were tentatively identified either by comparing the retention time and mass spectrometry data with that of reference compounds or by reviewing the literature. Three potential bioactive compounds, including (E)-pcoumaric acid, (Z)-p-coumaric acid, and apigenin-8-C-ß-D-(2"-O-α-L-rhamnosyl)-glucopyranoside, were detected in both the leaves of B. textilis McClure and rabbit plasma. Of the three compounds, apigenin-8-C-ß-D-(2"-O-α-L-rhamnosyl)glucopyranoside was identified based on its UV, MS, and NMR spectra. This study provides helpful chemical information for further pharmacology and active mechanism research on B. textilis McClure.

Rapid Screening for Flavone C-Glycosides in the Leaves of Different Species of Bamboo and Simultaneous Quantitation of Four Marker Compounds by HPLC-UV/DAD.

A strategy for analyzing flavone C-glucosides in the leaves of different species of bamboo was developed. Firstly, the flavone C-glycosides were extracted from the bamboo leaves (51 species in 17 genera) with methanol and chromatographed on silica gel 60 plates in automatic developing chamber (ADC2), and a qualitative survey using simple derivatization steps with the NP reagent was carried out. The flavone C-glycosides were found in 40 of 51 species of bamboo examined. Secondly, an HPLC method with photodiode array and multiple wavelength detector was optimized and validated for the simultaneous determination of flavone C-glycosides, including isoorientin, isovitexin, orientin, and vitexin in the leaves of three species of bamboo and the flavone C-glycosides were confirmed by LC/MS. The optimized HPLC method proved to be linear in the concentration range tested (0.2-100 µg/mL, r(2) ≥ 0.9997), precise (RSD ≤ 1.56%), and accurate (88-106%). The concentration ranges of isoorientin, isovitexin, orientin, and vitexin in three bamboo leaves samples were 1.00-2.78, 0-0.31, 0-0.07, and 0.20-0.68 mg/g, respectively. The proposed method was validated to be simple and reliable and can be a tool for quality control of bamboo leaf extract or its commercial products.

Coumarins from the leaves of Bambusa pervariabilis McClure.

A new pyrone-coumarin, 7,8-dihydroxy-3-(3-hydroxy-4-oxo-4H-pyran-2-yl)-2H-chromen-2-one (1), along with two known coumarins, scopoletin (2) and scopolin (3), was isolated from the 95% EtOH extract of the leaves of Bambusa pervariabilis McClure. Their structures were determined on the basis of spectroscopic techniques and chemical methods.

[Detection of antioxidative capacity of bamboo leaf extract by scavenging hydroxyl free radical].

By studying on absorption spectrum of red compound coming from the reaction system of Fe2+ and 1, 10-phenanthroline and the capacity of antioxidant TBHQ and bamboo leaf extract for scavenging hydroxyl free radical, some results were drawn as follows: the determining wavelength of bamboo leaf extract for scavenging hydroxyl free radical by spectrophotometric method is 509.1 nm, and IC50 (the value of antioxidant concentration at scavenging half of hydroxyl free radical)was used as the index to evaluate scavenging capacity. The determined IC50 values were TBHQ (0.040), M20 (0.378), M40 (0.323), M60 (0.334), and bamboo leaf extract could be used as natural antioxidant.

Flavonoids from the leaves of Pleioblastus argenteastriatus.

A new flavonoid, 5,7,3'-trihydroxy-6-C-beta-D-digitoxopyranosyl-4'-O-beta-D-glucopyranosyl flavonoside (1), along with four known flavonoids 5,7,4'-trihydroxy-3',5'-dimethoxy flavone (2), 5,3',4'-trihydroxy-7-O-beta-D-glucopyranosyl flavonoside (3), 5,4'-dihydroxy-3',5'-dimethoxy-7-O-beta-D-glucopyranosyl flavonoside (4), 5,3',4'-trihydroxy-6-C-[beta-D-glucopyranosyl-(1 --> 6)]-beta-D-glucopyranosyl flavonoside (5) were isolated from 95% EtOH extract of the leaves of Pleioblastus argenteastriatus. Their structures were determined on the basis of spectroscopic techniques and chemical methods.

[Detection of antioxidative capacity of bamboo leaf extract by scavenging superoxide anion free radical].

By studying absorption spectrum, oxidation velocity of pyrogallic acid reaction system, the effect of pyrogallic acid concentration and buffer pH value on the scavenging rate for superoxide anion free radical coming from reaction system was investigated, and some results were obtained as follows, the wavelength used for the pyrogallic acid reaction system was determined by spectrophotometric method: 319.5 nm. Some parameters of the reaction system were determined as follows: reaction volume: 10 mL, reaction time: 9 min, volume of pyrogallic acid (3 mmol x L(-1)): 0.3 mL, pH value of buffer: 8.2 and oxidation velocity: 0.035. The relation between scavenging rate for superoxide anion free radical and concentration of TBHQ and bamboo leaf extract samples was studied by our method, and IC50 (the value of antioxidant concentration at scavenging half of superoxide anion free radical) was used as the index to evaluate scavenging capacity. IC50 value of TBHQ and most effective samples were as follows: TBHQ (95.01 mg x L(-1)) and M40 (298.69 mg x L(-1)). M40 and other bamboo leaf extract could be used as natural antioxidant.

[Detection of antioxidative capacity of bamboo leaf extract by scavenging organic free radical DPPH].

By studying on absorption spectrum of DPPH solution and DPPH reaction system, the conclusion was drawn as follows, the wavelength for the determination of DPPH reaction system by spectrophotometric method was chosen to be 518.4 nm, DPPH reaction system was 4.00 mL of 257.7 mg x L(-1) DPPH+1 mL of antioxidant solution with the reaction time of DPPH reaction system of 40 min. The relation between DPPH radical scavenging rate and the concentration of TBHQ and BHT was studied, and IC50 (the value of antioxidant concentration for scavenging half of DPPH radical) was used as the index to evaluate scavenging capacity. The determining IC50 values were as follows: TBHQ (21.14 mg x L(-1)), BHT(42.09 mg x L(-1)) and M40 (108.40 mg x L(-1)). Bamboo leaf extract could be used as natural antioxidant.

Photodegradation of bensulfuron-methyl on soil surface.

Photolysis of bensulfuron-methyl on soil surface was studied under sunlight and UV light. Seven photoproducts were isolated and characterised by spectroscopic methods. The major processes in the photolysis of bensulfuron-methyl in soil are cleavage of the sulfonylurea bridge, scission of the SO2NH bond and contraction of the sulfuronylurea bridge. The rates of photodegradation of bensulfuron-methyl on different soils followed first-order rate kinetics with half lives of 21.9, 28.4, 36.9, 59.2 and 47.2 h (UV) and 23.1, 27.5, 29.1, 38.9 and 33.8 days (sunlight) for vertisol, alluvial, alfisol, red and laterite soils, respectively. The differences in rates of photodegradation were dependent upon the soil texture and organic matter content.