Essential Oils of Seven Lamiaceae Plants and Their Antioxidant Capacity

Oxidative stress has been reported as a cause of many diseases like Parkinson′s, Alzheimer′s, cardiovascular disease, and diabetes. Oxidative stress can also lead to cancer formation by promoting tumor development and progression. Antioxidants derived from Lamiaceae plants play an important role in natural medicine, pharmacology, cosmetology, and aromatherapy. Herein, we examine the antioxidative capacity of essential oils from seven aromatic Lamiaceae plants against the synthetic radicals DPPH and ABTS. Among the essential oils analyzed, the most robust scavenging capacities were found in mixtures of volatile compounds from thyme and savory. The scavenging activity of tested EOs against the ABTS radical was clearly higher than activity towards DPPH. Analysis of essential oils with weaker antioxidant activity has shown that volatile compounds from marjoram, sage, and hyssop were more active than EOs from lavender and mint. It can be suggested that the potent antioxidant capacity of thyme (Thymus vulgaris) and savory (Satyreja hortensis) are related to a high level of phenolic constituents, such as thymol and carvacrol. On the other hand, the elevated antioxidative power of marjoram, sage, and hyssop essential oils may also be due to their terpinene, o-cymene, terpinolene, and terpinen-4-ol constituents. Although non-phenolic components are less active than thymol or carvacrol, they may affect antioxidant capacity synergistically.     

高温弱还原气氛下高硅铝比煤灰变化行为的研究

利用XRD和FT-IR考察了两种高硅铝比煤(小龙潭褐煤、府谷烟煤)灰中矿物质在高温(1 100~1 500 ℃)弱还原气氛下的演变行为。通过FACT sage对煤中矿物质主要组分在高温下的变化进行了计算,并与XRD和FT-IR结果进行了比较和验证。结果表明,两种高硅铝比煤中矿物质在高温下的演变行为具有很大的差异,高温下,氧化钙含量较高的煤灰主要生成钙镁黄长石和钙长石等长石类矿物质,氧化钙含量较低的煤灰主要生成铝硅酸盐和少量的钙长石、拉长石等。氧化铁对晶体组成影响不明显;二氧化硅的含量随着温度的升高逐渐减少;低温共熔体系的存在降低了高硅铝比煤灰的灰熔点,同时,增加了高温煤灰中非晶体的含量。FACT sage热力学计算结果与XRD、FT-IR分析结果一致。     

Electrochemical behaviour of rosmanol 9-ethyl ether,a diterpene lactone antioxidant isolated from sage

The electrochemical behaviour and mechanism of the redox process of the natural antioxidant rosmanol 9-ethyl ether, isolated fromSaliva officinalis L., were studied. The cyclic voltammograms of rosmanol 9-ethyl ether (R9EE), at characteristic pH values, and the electrochemical parameters for all investigated pH values were measured. Three characteristic pH regions, each with different behaviour of R9EE, were identified. In regions of pH < 4 and pH > 5 only one anodic peak appeared, whereas in the solutions of pH 4–5 two anodic peaks could be noted. The overall oxidation mechanism at pH < 4 is an e.H.e.H. oxidation mechanism, which as a final product gives a quinonic molecule. The influence of pH on the second oxidation peak potential tends towards zero in accordance with the preceding dissociation of the one of phenolic groups, thus suggesting an e.e.H. mechanism at pH > 5. This means that at the pH values expected in plant cells, R9EE has an unexpected structure, making this substance a potent antioxidant. Electrochemical and spectrophotometric measurements enabled us to establish an extremely low pK _a value (4.35) for R9EE.     

The Changes in Bioactive Compounds and Antioxidant Activity of Chia (Salvia hispanica L.) Herb under Storage and Different Drying Conditions: A Comparison with Other Species of Sage

Studies on herb chia (Salvia hispanica L.) are very limited. Therefore, the aim of this study was to assess how different drying methods and periods of storage affect the bioactive properties of the herb Salvia hispanica and to compare it with other species of sage (Salvia officinalis L. and Salvia sclarea L.). In fresh herbs, directly after drying (freeze-drying, natural drying, and drying at 30, 40, and 50 °C), and after storage (3, 6, and 12 months), the following analyses were performed: content of total carotenoids and total polyphenols, polyphenol profile (including 25 compounds), and antioxidant activity. Additionally, the basic chemical compositions of the herbs were analyzed. To the best of our knowledge, the content of total carotenoids and the quantitative polyphenol profile in Salvia hispanica and Salvia sclarea were evaluated for the first time. The obtained results showed that the barely investigated herb Salvia hispanica is rich in polyphenolic compounds and shows high antioxidant activity. In all the tested species, rosmarinic acid was the most abundant polyphenolic compound. The use of different drying methods allowed us to determine that freeze-drying was the most effective for preserving polyphenols and carotenoids. Long-term storage up to 12 months resulted in a gradual reduction in antioxidant activity and in the content of polyphenols and carotenoids.     

Indirect determination of superoxide anion radical in the plant of red sage based on vanillin-8-aminoquinoline with fluorescence

A novel spectrofluorimetric method using vanillin-8-aminoquinoline (VAQ) as fluorescent probe was developed for the determination of superoxide anion radical (O₂⁻). The new fluorescent probe was characterized by elemental analysis and IR spectra. Under the optimum conditions of the determination, the linear calibration range and the detection limit of the developed method for superoxide anion radical were in the range (0.0-1.0)×10⁻⁵ and 2.0×10⁻⁸ mol l⁻¹, respectively. The effect of interferences was studied. The proposed method was applied to determine the generation rate of superoxide anion radical in the course of aging in red sage successfully.     

精油中挥发性成分GC/FTIR与GC/MS联合分析

采用同时蒸馏萃取(SDE)法获得了香紫苏(Salvia sclarea L.)精油,利用气相色谱/傅里叶变换红外光谱联用(GC/FTIR)和气相色谱/质谱联用(GC/MS)相结合的手段,对其挥发成分进行了定性和定量分析,着重讨论了GC/FTIR在精油分析中的应用研究。通过不同波数官能团(Gram-Schmidt)重建红外光谱图、红外光谱差谱技术及质谱等相互验证的方法,大大提高了香紫苏油挥发成分的定性分析准确性。