Natural antioxidants produced in oxidized lipid/amino acid browning reactions

1-Substituted pyrroles (1 and2) and1-substituted 2-(1′-hydroxypropyl)pyrroles (3–5) were produced in reactions between a lipid peroxidation product, 4,5(E)-epoxy-2(E)-heptenal, and the amino acid lysine. The antioxidative activity of compounds1–5 was studied. Oxidative stability was evaluated in refined soybean oil containing compounds1–5, butylated hydroxytoluene (BHT),n-propyl gallate orl-lysine, at concentrations of 50–200 ppm. Oils were either oxidized at 60°C and oxidation products determined by the thiobarbituric acid-reactive substances assay, or they were oxidized at 110°C by the Rancimat method. Although both methods gave similar results, greater differences were observed at 60°C than at 110°C. Addition of compounds1–5,l-lysine, BHT, and propyl gallate significantly (P<0.01) protected the oil against oxidation. The effectiveness order found was:l-lysine << compounds3–4 < compounds1–2 < compound5 ≈ BHT << propyl gallate.     

A fourier transform infrared spectroscopic method for determining butylated hydroxytoluene in palm olein and palm oil

A simple, rapid, and direct FTIR spectroscopic method was developed for the determination of BHT content in refined, bleached, and deodorized (RBD) palm olein and RBD palm oil. The method used sodium chloride windows with a 50-mm transmission path. Fifty stripped oil samples of both RBD palm olein and RBD palm oil were spiked with known amounts of BHT concentrations up to 300 mg/kg (ppm). The data were separated into two sets for calibration and validation using partial least squares models. FTIR results for both oils correlated well with results obtained by the IUPAC HPLC-based method. For RBD palm olein, the coefficient of determination (R ²) was 0.9907 and the SE of calibration (SEC) was 8.47 ppm. For RBD palm oil, an R ² of 0.9848 and an SEC of 10.73 ppm were achieved. Because of the significant decrease in analysis time and reduction in solvent usage, this FTIR method for BHT is especially well suited for routine quality control applications in the palm oil industry.     

Health-beneficial qualities of the edible mushroom, Agrocybe aegerita

The black poplar mushroom, Agrocybe aegerita is a popular edible mushroom with reported anti-tumor properties. A bioactivity-guided investigation gave positive results for ceramide (1), methyl-β-d-glucopyranoside and α-d-glucopyranoside, along with already reported linoleic acid and its methyl ester. The structure elucidation of the above was accomplished by NMR and mass spectral methods. The ceramide (1) inhibited cyclooxygenase enzymes, COX-1 and -2, by 43 and 92.3%, respectively at 25 μg/ml (34.4 μM). The 50% inhibition concentration (IC₅₀) of compound 1 against COX-2 was 5.3 μg/ml (7.3 μM). Similarly, its anti-cancer potential was investigated against five human cancer cell lines in vitro and it was found to inhibit the proliferation of stomach, breast and CNS cancer cell lines at 26.9, 23.2 and 39.1%, respectively, at 100 μg/ml (139 μM) concentration. This is the first report of the isolation of ceramide from A. aegerita and its COX and tumor cell proliferation inhibitory activities. This suggested that the consumption of A. aegerita would assist in alleviating inflammatory conditions, as well as reducing the development of the above cancers.     

凝胶渗透色谱-气相色谱法测定食品中BHA、BHT

建立了凝胶渗透色谱-气相色谱法测定油炸食品中丁基羟基茴香醚(BHA)和二丁基羟基甲苯(BHT)两种抗氧化剂。采用乙酸乙酯-环己烷(体积比为1∶1)溶液提取样品中BHA和BHT。提取液经凝胶渗透色谱(GPC)净化。采用配有FID检测器的气相色谱进行测定。方法准确度高、稳定性好。加标回收率为85.7%~94.0%。BHA和BHT检出限为0.002 mg/m L。BHA和BHT在5 mg/L~100 mg/L时,线性相关系数在0.999 6以上。     

气相色谱法测定食用油中BHA和BHT残留量的对比研究

目的建立气相色谱法测定食用油中叔丁基羟基茴香醚(butyl hydroxyanisole,BHA)和二丁基羟基甲苯(butylated hydroxytoluene,BHT)的残留量。方法使用无水乙醇萃取样品,经中性氧化铝吸附杂质,HP-5毛细管柱分离,使用气相色谱仪定量分析BHA和BHT在食用油中的残留量。同时,与GB/T 5009.30中的方法进行对比,考察了本方法的线性、重现性、回收率和精密度。结果本方法中BHA和BHT的线性范围分别为2.02~40.48 ng和2.07~41.36 ng,标准曲线方程分别为Y=16.61X+10.03(r=0.9996)和Y=20.14X+16.56(r=0.9997);BHA和BHT的检出限分别为92.4 ng/kg和108.6 ng/kg,加标回收率分别为98.94%(相对标准偏差为0.33%)、98.69%(相对标准偏差为0.34%)。结论本实验建立的方法灵敏度高、定量准确,和国标法相比,具有简单实用的特点,适合食用油中BHA和BHT残留量的检测。     

气相色谱法快速测定食用油中3种抗氧化剂

采用无水乙醇提取食用油中的抗氧化剂叔丁基羟基茴香醚(BHA)、二丁基羟基甲苯(BHT)、特丁基对苯二酚(TBHQ),提取液经冷冻过滤后用气相色谱法测定其中的BHA、BHT、TBHQ的含量.试验得出方法最低检出限为BHA、BHT 1.0 mg/kg,TBHQ 2.0mg/kg,相对标准偏差为1.13％ ～3.74％,3种抗氧化剂加标回收率为93.98％～102.22％.该方法简便、快速、稳定、可靠.     

Isolation,characterization and antioxidant capacity assessment of the bioactive compounds derived from Hypoxis rooperi corm extract (African potato)

The rhizome of the plant Hypoxis rooperi (“African potato”) is known for its traditional and ethnomedical uses in the treatment of benign prostatic hyperplasia and other diseases. We have characterized an extract derived from H. rooperi, isolated its major bioactive compound, hypoxoside, and obtained its aglycone, rooperol, by enzymatic digestion. Absorption, fluorescence emission and bidimensional NMR complete spectral data of these compounds were obtained. The antioxidant capacity of both compounds was fully analyzed through the thiobarbituric acid reactive substances (TBARS) and Trolox equivalent antioxidant capacity (TEAC) assays, and it was compared to catechins and olive biophenolics. Both compounds showed a strong antioxidant capacity, although rooperol exhibited a higher antioxidant activity against lipid peroxidation which correlated to its strong affinity for phospholipid membranes as derived from its extremely high lipid/water partition coefficient (K_p = 3.4 × 10⁴). The study of the lipophilic (EtOH) and hydrophilic (water) TEAC values revealed that more hydrophobic compounds, had greater lipophilic TEAC values than hydrophilic ones, probably indicating that lipophilic TEAC assay may be more reliable for these compounds. The H. rooperi extract also showed higher antioxidant efficacy compared to other strong antioxidant herbal extracts, such as olive leaf or green tea. Moreover, neither evidence of acute oral toxicity nor adverse effects were observed when the H. rooperi commercial extract containing 45% hypoxoside was used at a dosage of 2000 mg/kg. The results obtained in this work may contribute to understanding the biological activity described for these dicatechols and the African potato extract for food and cosmetic applications.     

迷迭香抗氧化剂抗氧化性能的研究

通过与2,6-二叔丁基对甲苯酚抗氧化剂的对比探讨了迷迭香抗氧化剂在蛇油和葡萄籽油中的抗氧化效果,并对迷迭香抗氧化剂进行紫外谱图分析。结果表明：迷迭香抗氧化剂添加量在0．04％-0．05％之间的抗氧化效果最佳。随着用量的增加,抗氧化性能减弱,到一定程度不仅没有抗氧化作用,反而表现出明显的催化氧化效果。迷迭香抗氧化剂在UVA波段具有良好的吸收峰,可提高防晒化妆品的防晒黑效果。     

毛细管法测定防老剂D与BHT的熔点

为了准确测定防老剂D与BHT的熔点,用两端开口毛细管法、一端开口毛细管法和数字熔点仪测定了两种防老剂的熔点。结果表明,两端开口毛细管法测得的数据精密度较高,而且此法方便、经济。总结了两端开口毛细管法测定防老剂D与BHT的影响因素及注意事项。     

Supercritical fluid extraction and hydrodistillation for the recovery of bioactive compounds from Lavandula viridis L’Hér

The chemical profiles of bioactive essential oil and extracts obtained by hydrodistillation (HD) and supercritical fluid extraction (SFE), respectively, from Lavandula viridis were compared. The SFE was performed at 40 °C and at extraction pressures of 12 or 18 MPa in two different separators. Evaluation of the essential oil and SFE extracts by GC–FID and GC–IT–MS revealed that oxygen-containing monoterpenes were the major constituents in both cases, but there were important differences between the chemical profiles produced by the different extraction techniques. More compounds were isolated by HD but higher yields were achieved by SFE. Camphor was the main component identified in the essential oil (31.59 ± 1.32%), and in extracts from the first (1.61 ± 0.34%) and second SFE separators (22.48 ± 1.49%) at 12 MPa. In contrast, the first separator SFE extract at 18 MPa (heavy compounds) was dominated by myrtenol (5.38 ± 2.04%) and camphor (4.81 ± 1.93%), whereas the second separator SFE extract (volatiles) was dominated by verbenone (13.97 ± 5.27%). The essential oil and heavy compound extracts from the first separator possessed antioxidant and anti-cholinesterase activities. Our data show that phytochemicals from the aerial parts of L. viridis could be developed as natural antioxidant and anti-cholinesterase drugs, with particular applications in the symptomatic treatment of Alzheimer’s disease.