Two new triterpenoid glycosides from the stems of Camellia oleifera Abel

Two new oleanane-type triterpenoid glycosides, 3-O-β-D-xylopyranosyl-(1→2)-α-L-arabinopyranosyl-(1→3)-[β-D-glucuronopyranosyl-(1→2)]-β-D-glucuronopyranosyl-22α-angeloyloxyolean-12-ene-15α,16α,28-triol(1) and 3-O-β-D-xylopyranosyl-(1→2)-α-L-arabinopyranosyl-(1→3)-[β-D-glucuronopyranosyl-(1→2)]-β-D-glucuronopyranosyl-21β-acetyl-22α-angeloyloxyolean-12-ene-16α,28-diol (2) were isolated from the stems of Camellia oleifera Abel. Their structures were elucidated by means of spectroscopic methods and chemical evidence. The cytotoxic activities of compounds 1–2 were evaluated against five human tumour cell lines (HCT-8, BGC-823, A5049, and A2780). Compounds 1–2 showed cytotoxic activity against five human cancer cell lines, with IC₅₀ values ranging from 3.15 to 7.32 μM.     

Triterpenoids from the Roots of Camellia oleifera C.Abel and Their Cytotoxic Activities

Three new triterpenoids, 21β,22α‐diangeloyloxy‐3β,15α,16α,28‐tetrahydroxyolean‐12‐en‐23‐al ( 1 ), 21β‐angeloyloxy‐3β,15α,16α,28‐tetrahydroxy‐22α‐(2‐methylbutanoyloxy)olean‐12‐en‐23‐al ( 2 ), and 21β‐angeloyloxy‐3β,16α,28‐trihydroxy‐22α‐(2‐methylbutanoyloxy)olean‐12‐en‐23‐al ( 3 ), along with six known triterpenoids, were isolated from the roots of Camellia oleifera C.Abel . The structures of compounds 1 – 3 were elucidated on the basis of spectroscopic analyses. Moreover, all compounds isolated were evaluated for their cytotoxic activities by MTT (=3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bromide) assay.     

New Triterpenoid Glycosides from the Roots of Camellia oleifera Abel

Five new triterpenoid saponins, oleiferosides I–M ( 1 – 5 , resp.) were isolated from the roots of Camellia oleifera Abel . Their structures were elucidated by a combination of 1D‐ and 2D‐NMR spectroscopy, mass spectrometry, and chemical methods. All the compounds were identified as oleanane‐type saponins with sugar moieties linked to C(3) of the aglycone. In addition, cytotoxic activities of these saponins were evaluated against four human tumor cell lines (A549, B16, BEL‐7402, and MCF‐7) by using the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) in vitro assay. All of the compounds showed significant cytotoxic activities against the tested cell lines.     

Authentication of Camellia oleifera Abel Oil by Near Infrared Fourier Transform Raman Spectroscopy

Adulteration of Camellia oleifera Abel. oil with other cheaper oil has been a long‐term problem in Taiwan because the price of Camellia oleifera Abel. oil is much higher than that of other edible oils due to its distinguished physiological properties. To develop an efficient method for determining the authenticity of Camellia oleifera Abel. oil is of great importance. In previous study (Appl. Spectrosc. 2003 , 57, 413), we showed that the Raman intensity ratio of ν₁₆₅₆/ν₁₄₃₉ was capable of reflecting precisely the degree of unsaturation in edible oils. Accordingly, we further present this Raman method to determine the authenticity of Camellia oleifera Abel. oil. It showed that the intensity ratio (I_{ν1656/ν1439}) changed concomitantly with the magnitude of double bonds in the binary mixtures of Camellia oleifera Abel. oil blended with other edible oil. A linear relationship with a high correlation coefficient (R² = 0.9938) between the Raman intensity ratio of ν₁₆₅₆/ν₁₄₃₉ and the percentage of Camellia oleifera Abel. oil was obtained, which could be used to determine the authenticity of Camellia oleifera Abel. oils collected from various markets. It shows that FT‐Raman spectroscopy provides a direct, simple, rapid, and non‐invasive method to probe the authenticity of Camellia oleifera Abel. oil.     

Characterization of the Volatile Compounds in Camellia oleifera Seed Oil from Different Geographic Origins

Volatile flavor of edible oils is an important quality index and factor affecting consumer choice. The purpose of this investigation was to characterize virgin Camellia oleifera seed oil (VCO) samples from different locations in southern China in terms of their volatile compounds to show the classification of VCO with respect to geography. Different samples from 20 producing VCO regions were collected in 2020 growing season, at almost the same maturity stage, and processed under the same conditions. Headspace solid-phase microextraction (HS-SPME) with a gas chromatography–mass spectrometer system (GC–MS) was used to analyze volatile compounds. A total of 348 volatiles were characterized, including aldehydes, ketones, alcohols, acids, esters, alkenes, alkanes, furans, phenols, and benzene; the relative contents ranged from 7.80–58.68%, 1.73–12.52%, 2.91–37.07%, 2.73–46.50%, 0.99–12.01%, 0.40–14.95%, 0.00–27.23%, 0.00–3.75%, 0.00–7.34%, and 0.00–1.55%, respectively. The VCO geographical origins with the largest number of volatile compounds was Xixiangtang of Guangxi (L17), and the least was Beireng of Hainan (L19). A total of 23 common and 98 unique volatile compounds were detected that reflected the basic and characteristic flavor of VCO, respectively. After PCA, heatmap and PLS-DA analysis, Longchuan of Guangdong (L8), Qingshanhu of Jiangxi (L16), and Panlong of Yunnan (L20) were in one group where the annual average temperatures are relatively low, where annual rainfalls are also low. Guangning of Guangdong (L6), Yunan of Guangdong (L7), Xingning of Guangdong (L9), Tianhe of Guangdong (L10), Xuwen of Guangdong (L11), and Xiuying of Hainan (L18) were in another group where the annual average temperatures are relatively high, and the altitudes are low. Hence, volatile compound distributions confirmed the differences among the VCO samples from these geographical areas, and the provenance difference evaluation can be carried out by flavor.     

HPLC法测定油茶枯饼中两种主要黄酮苷

建立了油茶枯饼中两种主要黄酮苷：山奈酚3-0-[2-O-β-D-木糖-6-0-α-L-鼠李糖]-β-D-葡萄糖苷（Ⅰ）和山奈酚3-0-[2-O-β-D-半乳糖-6-0-α-L-鼠李糖]-β-D-葡萄糖苷（Ⅱ）的高效液相色谱测定方法。采用C18 Column（BDS,Hypersil,250mm×4.6 mm）,流动相为V（乙腈）∶V（0.1%H3PO4）=20∶80,流速1 mL/min;检测波长266 nm。结果表明,黄酮苷Ⅰ的线性范围为60-2000 mg/L（R=0.9993,n=6）,平均回收率99.5%,RSD为1.6%;黄酮苷Ⅱ的线性范围为30-1200mg/L（R=0.9995,n=6）,平均回收率100.7%,RSD为1.2%。该方法可用于检测油茶枯饼及其提取物中两种主要黄酮苷。     

Maturity Stage Discrimination of Camellia oleifera Fruit Using Visible and Near-Infrared Hyperspectral Imaging

The maturity of Camellia oleifera fruit is one of the most important indicators to optimize the harvest day, which, in turn, results in a high yield and good quality of the produced Camellia oil. A hyperspectral imaging (HSI) system in the range of visible and near-infrared (400–1000 nm) was employed to assess the maturity stages of Camellia oleifera fruit. Hyperspectral images of 1000 samples, which were collected at five different maturity stages, were acquired. The spectrum of each sample was extracted from the identified region of interest (ROI) in each hyperspectral image. Spectral principal component analysis (PCA) revealed that the first three PCs showed potential for discriminating samples at different maturity stages. Two classification models, including partial least-squares discriminant analysis (PLS-DA) and principal component analysis discriminant analysis (PCA-DA), based on the raw or pre-processed full spectra, were developed, and performances were compared. Using a PLS-DA model, based on second-order (2nd) derivative pre-processed spectra, achieved the highest results of correct classification rates (CCRs) of 99.2%, 98.4%, and 97.6% in the calibration, cross-validation, and prediction sets, respectively. Key wavelengths selected by PC loadings, two-dimensional correlation spectroscopy (2D-COS), and the uninformative variable elimination and successive projections algorithm (UVE+SPA) were applied as inputs of the PLS-DA model, while UVE-SPA-PLS-DA built the optimal model with the highest CCR of 81.2% in terms of the prediction set. In a confusion matrix of the optimal simplified model, satisfactory sensitivity, specificity, and precision were acquired. Misclassification was likely to occur between samples at maturity stages two, three, and four. Overall, an HSI with effective selected variables, coupled with PLS-DA, could provide an accurate method and a reference simple system by which to rapidly discriminate the maturity stages of Camellia oleifera fruit samples.     

Combined application of macroporous resin and high speed counter-current chromatography for preparative separation of three flavonoid triglycosides from the leaves of Actinidia valvata Dunn

In this paper, the combined techniques of macroporous resin column chromatography and high speed counter-current chromatography were applied for preparative separation of flavonoid triglycosides from the leaves of Actinidia valvata Dunn, a famous Chinese medicinal herb. Twelve kinds of macroporous resins were investigated by adsorption and desorption tests. HPD-300 resin showed the maximum effectiveness and thus was selected for the first cleaning-up, in which 20% ethanol was used to remove the undesired constituents and 60% ethanol to elute the targets. The crude extract was then purified by high speed counter-current chromatography with the solvent system composed of ethyl acetate-n-butanol-water (2:1:3 and 4:1:5, v/v). Three flavonoid triglycosides, namely, kaempferol 3-O-α-L-rhamnopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→6)-β-D-galactopyranoside, kaempferol 3-O-α-L-rhamnopyranosyl-(1→3)-(4-O-acetyl-α-L-rhamnopyranosyl)-(1→6)-β-D-galactopyranoside and kaempferol 3-O-α-L-rhamnopyranosyl-(1→3)-(2,4-di-O-acetyl-α-L-rhamnopyranosyl)-(1→6)-β-D-galactopyranoside, were obtained. The purities of the separated compounds were all over 95% as determined by HPLC area normalization method. Their chemical structures were confirmed by UV, MS, NMR, and the standards.     

Two new kaempferol glycosides from the seeds of Camellia semiserrata Chi

Two new acetylated kaempferol glycosides were isolated from the seeds of Camellia semiserrata Chi,their structures were elucidated as kaempferol-3-O-[(3-O-acetyl)-α-L-rhamnopyranosyl(1→3)(4-O-acetyl)-α-L-rhamnopyranosyl(1→6)-β-D-glucopyranoside] (1) and kaempferol-3-O-[(2-O-acetyl)-α-L-rhamnopyranosyl(1→3)(4-O-acetyl)-α-L-rhamnopyranosyl(1→6)-β-D-gluco -pyranoside](2) by spectral experiments(including ESI-MS,1D- and 2D-NMR).     

A new cytotoxic salannin-class limonoid alkaloid from seeds of Azadirachta indica A. Juss

Azadiramide A (1), a new salannin-class limonoid alkaloid, inhibits growth of human breast cancer MDA-MB-231 cell line with IC₅₀ value of 2.70±0.63 μmol/L.     

Synergism and foaming properties in binary mixtures of a biosurfactant derived from Camellia oleifera Abel and synthetic surfactants

A biosurfactant, named tea saponin (TS), was isolated and purified from the defatted seed of Camellia oleifera Abel. The characterization of TS including molecular weight, glycosyl composition, and thermal behavior as well as the surface and foaming properties was conducted. The synergistic interactions of binary systems of CTAB-TS, SDS-TS, and Brij35-TS were investigated. The results show that TS had a weight-average molecular weight of 809.12 g mol(-1) and contained four aglycones of L-rhamnose, D-galactose, D-glucose, and D-glucuronic acid. The critical micelle concentration (cmc) of 2.242 mmol L(-1) and the minimum surface tension (γ(cmc)) of 43.5 mN m(-1) were determined for TS. Synergisms in surface tension reduction efficiency, in mixed micelle formation, and in surface tension reduction effectiveness were observed in CTAB-TS and SDS-TS systems, whereas that was not shown in Brij35-TS mixtures. The mixtures of TS with CTAB and SDS showed synergism in foaming efficiency, but this synergism did not exist in Brij35-TS system with respect to the surface properties. Nevertheless, there appears to be no significant correlation between foam stability and the surface properties.     

Utilization of camellia oleifera shell for production of valuable products by pyrolysis

Camellia oleifera shell is used as the feedstock to prepare the valuable products by pyrolysis using microwave heating at 400-800 °C. The yield of pyrolysis product is influenced by pyrolysis temperature, which indicates that high pyrolysis temperature promotes to generate bio-gas and restrains the production of biochar. However, pyrolysis temperature little influences the yield of bio-oil. The main compound of bio-oil is phenols, hydrocarbons, ketones, aldehydes and furans, respectively. While, bio-oil produced at 600 °C has as high as 78 % of phenols, which has potential application in chemical industries. The pyrolysis temperature has significantly influenced the composition and heating value of bio-gas. The maximum heating value of bio-gas is 12.44 MJ/Nm³, which is achieved at 600 °C. The physiochemical properties of biochar are also influenced by pyrolysis temperature. Biochar could be used as an adsorbent to adsorb Ag⁺ from aqueous solution, which is formed the value-added ABiochar composite by reduction. The adsorption and reduction process of Ag⁺ are investigated. While, ABiochar composite can be used as the catalyst for methylene blue degradation. ABiochar composite can be also used in the lithium ion battery cathode material for energy storage.     

Optimization of Extraction Conditions for Flavonoid Composition and Antioxidant Activity of Radix Scutellariae

Microwave, ultrasonic, and reflux extraction were compared to provide an optimized method for flavonoids from Radix Scutellariae including the antioxidant activity of the extracts. The antioxidant activities of the extracts were evaluated by 2,2-diphenyl-1-picrylhydrazyl and oxygen radical absorbance capacity assays. Baicalin, wogonoside, baicalein, wogonin, and oroxylin A were quantified using ultra-high performance liquid chromatography. For microwave extraction, with a ten minutes treatment, the extraction efficiencies of the analytes were higher than treatments by refluxing for 180 minutes and sonication for sixty minutes. In addition, the antioxidant activity of the microwave extracts was slightly higher than the extracts obtained by the other methods. Microwave extraction conditions were further optimized by a single-factor experiment and the optimum conditions were 50 percent ethanol–water (volume by volume), an extraction temperature of 100 degrees celsius, an extraction time of ten minutes, and a sample to solvent ratio of 1:50. This study combines extraction, phytochemistry, and bioactivity to screen the most efficient extraction procedure for flavonoids from Radix Scutellariae.     

Flavonoid Glycosides from the Leaves of Machilus philippinensis

Thirteen flavonoid glycosides ( 1‐7 , 11‐13 , 15 , 17 , and 18 ) were isolated from the EtOH extract of the leaves of Machilus philippinensis. Of these, kaempferol 3‐O‐(2‐O‐β‐D ‐apiofuranosyl)‐α‐L ‐rhamnopyranoside ( 1 ) and kaempferol 3‐O‐(2‐O‐β‐D ‐apiofuranosyl)‐a‐L ‐arabinofuranoside ( 2 ) are new natural products. By application of HPLC‐SPE‐NMR hyphenated technique, five additional flavonol glycosides were characterized ( 8‐10 , 14 , and 16 ). Their structures were elucidated based on spectroscopic analysis. Of these, quercetin 3‐O‐(6‐O‐α‐L ‐rhamnopyranosyl)‐β‐D ‐galactopyranoside ( 5 ) and kaempferol 3‐O‐α‐L ‐arabinopyranoside ( 15 ) showed moderate inhibitory activity against α‐glucosidase type IV from Bacillus stearothermophilus with the IC₅₀ values of 19.5 and 19.0 μM, respectively.     

超声微波酶解协同提取油茶壳中原花青素

建立了超声微波酶解协同提取油茶壳中原花青素的方法。通过单因素试验,探讨了超声微波协同提取油茶壳中原花青素过程中各主要因素对原花青素提取率的影响规律。实验中发现,往提取液中加入适量纤维素酶,可显著提高原花青素的提取率。在此基础上,通过正交试验,优化并获得了超声微波酶解协同提取原花青素的最适宜条件。最适宜提取条件为:超声波频率40 KHz、微波功率200 W、提取时间60 s、料液比1∶6、提取温度50℃、0.1%纤维素酶0.5 mL、提取次数2次。在最适宜条件下,原花青素的提取率为4.46%,分别是超声提取、微波提取和超声-微波协同提取的4.0、3.3和1.8倍。本文所建立的超声微波酶解协同提取油茶壳中原花青素的方法具有简便、快速、高效和节能等优势,有利于应用推广。     

Flavonoid Aglycones and Indole Alkaloids from the Roots of Acacia Confusa

From the methanolic extract of the roots of Acacia confusa Merr. (Leguminosae), (‐)‐2,3‐cis‐3,4‐cis‐4′‐methoxy‐3,3′,4,7,8‐pentahydroxyflavan ( 1 ), (‐)‐2,3‐cis‐3,4‐cis‐3,3′,4,4′,7,8‐hexahydroxyflavan ( 2 ), (‐)‐2,3‐trans‐3′,4′,7,8‐tetrahydroxydihydroflavonol ( 3 ), (+)‐catechin ( 4 ), (‐)‐epicatechin ( 5 ), 3′,4′,7,8‐tetrahydroxyflavonol ( 6 ) together with N‐methyltryptamine ( 7 ) and N,N‐dimethyltryptamine ( 8 ) were isolated, and their structures were established by analysis of their spectroscopic data. Among them, compound 1 was a new flavonoid. Additionally, the results of chromatographic bioassay on lettuce seeds indicated that compounds 7 and 8 exhibited significant phytotoxicity at a concentration lower than 14 mM.     

Microwave-assisted extraction of polyphenols from Camellia oleifera fruit hull

The abundant fruit hulls of tea-oil tree (Camellia oleifera) are still underutilized and wastefully discaded to pollute the environment. In order to solve this problem and better utilize the fruit hulls of C. oleifera, a microwave-assisted extraction system was used to extract their polyphenols using water as the extraction solvent. A central composite design (CCD) was used to monitor the effects of three extraction processing parameters--liquid:solid ratio (mL/g), extraction time (min) and extraction temperature (°C)--on the polyphenol yield (%). The results showed that the optimal conditions were liquid:solid ratio of 15.33:1 (mL/g), extraction time of 35 min and extraction temperature of 76 °C. Validation tests indicated that under the optimized conditions the actual yield of polyphenols was 15.05 ± 0.04% with RSD = 0.21% (n = 5), which was in good agreement with the predicted yield. Phenolic compounds in the extracts were analysed by HPLC, and gallic acid was found to be the predominant constituent. The total flavonoid content in the extracts was determined and high total flavonoid content was revealed (140.06 mg/g dry material).     

刺五加叶中黄酮类化合物的结构鉴定

利用电喷雾质谱发现刺五加叶中存在4种黄酮类化合物,进一步分离得到其中的两种,经核磁质谱鉴定,一种为槲皮甙(槲皮素－3－O－α－L－鼠李糖),另一种为金丝桃甙(槲皮素－3－O－β-D－半乳糖).其余两种难以分离的黄酮甙经电喷雾多级串联质谱分析,初步推断为槲皮素和芦丁(槲皮素－3-O－芦丁糖).以上4种均为黄酮醇类化合物,除金丝桃甙外,其它3种为刺五加叶中尚未见报道的黄酮类成分.     

Unusual ether-type resin glycoside dimers from the seeds of Cuscuta chinensis

Two new resin glycosides, cuses 3 (1) and 4 (2), were initially obtained from the seeds of Cuscuta chinensis. Both of them contained a reducing glucose unit, and thus existed as a pair of isomers. In order to solve the existing problem of tautomerism, the remanent resin glycoside fraction was converted into aminoalditol derivatives with p-anisidine, and then another eight new resin glycosides cuses 5–12 (3–10) were further isolated. Cuses 7–12 (6–10) were considered to be generated via glycosidation of two acylated oligosaccharides, and thus characterized as ether-type resin glycoside dimers. Their structures including absolute stereochemistry were elucidated by a combination of spectroscopic and chemical methods. Compounds 3–10 exhibited cytotoxic activity toward MCF-7, SMMC-7721, and MG-63 cell lines with IC₅₀ values ranging from 8.72 to 59.35 μg/mL.     

Five New Flavonol Glycosides from the Fresh Flowers of Camellia reticulata

Thirty‐one phenolic constituents, including 13 flavonol glycosides, 3 dihydroflavonols, 5 flavan‐3‐ols, 4 hydrolyzable tannins, and 6 phenylpropanoids, were isolated from the fresh flowers of Camellia reticulata for the first time. Five of them are new flavonol glycosides. Their structures were elucidated by detailed spectroscopic analyses.