Metabolic profile and biological activities of Lavandula pedunculata subsp. lusitanica (Chaytor) Franco: Studies on the essential oil and polar extracts

We investigated the metabolic profile and biological activities of the essential oil and polar extracts of Lavandula pedunculata subsp. lusitanica (Chaytor) Franco collected in south Portugal. Gas chromatography–mass spectrometry (GC–MS) analysis revealed that oxygen-containing monoterpenes was the principal group of compounds identified in the essential oil. Camphor (40.6%) and fenchone (38.0%) were found as the major constituents. High-performance liquid chromatography with diode array detection (HPLC–DAD) analysis allowed the identification of hydroxycinnamic acids (3-O-caffeoylquinic, 4-O-caffeoylquinic, 5-O-caffeoylquinic and rosmarinic acids) and flavones (luteolin and apigenin) in the polar extracts, with rosmarinic acid being the main compound in most of them. The bioactive compounds from L. pedunculata polar extracts were the most efficient free-radical scavengers, Fe²⁺ chelators and inhibitors of malondialdehyde production, while the essential oil was the most active against acetylcholinesterase. Our results reveal that the subspecies of L. pedunculata studied is a potential source of active metabolites with a positive effect on human health.     

利用衍生化试剂DTNB测定枸杞中谷胱甘肽

利用5,5'-二硫硝基苯甲酸(DTNB)衍生化试剂和植物材料同步破壁提取的样品处理方法,采用电喷雾质谱法和分光光度法对枸杞中还原型谷胱甘肽(GSH)进行定性、定量分析。枸杞样品提取过程中GSH受破壁后胞外化学环境的影响导致氧化变性。利用5,5'-二硫硝基苯甲酸(DTNB)衍生化试剂同步提取,因生成稳定的GSH的衍生化产物避免了GSH氧化变性导致的GSH分析信息丢失。用UV-Vis分光光度法测定GSH含量,发现枸杞中含有丰富的GSH。标准加入法测定枸杞干品中GSH,其含量范围达(6.56±0.54)mg/g,是目前所测植物样品中GSH含量较高的物种。本研究对药用植物胞内活性物质的准确分析提供方法学的尝试,并通过测定发现枸杞中富含GSH。     

Dual effect of free and liposomal forms of phenolic lipids on the activity of GPI-anchor-deprived acetylcholinesterase from erythrocytes

The effect of free and liposomal forms of phenolic lipids isolated from rye grains, cashew nut-shell liquid (CNSL) from Anacardium occidentale, and Merrulius tremellosus fruit body on the glycosyl-phosphatidylinositol (GPI)-anchor-deprived erythrocyte-ghost acetylcholinesterase activity was studied. It was shown that the observed effect distinctly depends on the form of the phenolic lipids available for interaction with the enzyme. The free form of the phenolic lipids decreased the enzymatic activity of GPI-anchor-deprived acetylcholinesterase less than the acetylcholinesterase anchored in erythrocytes ghosts, whereas the same phenolic lipids present in the medium in liposomal form, increased it.     

地鳖虫中抑制AchE活性物质的提取工艺优化

在浸提时间、浸提温度、料液比等单因素实验基础上,运用响应面法优化了地鳖虫中抑制AchE活性物质的提取条件,最终得出其最佳提取工艺为:浸提时间5.1h、浸提温度61.1℃、浸提料液比1∶20.3,在此条件下获得的粗提物对AchE酶活力的抑制率最高可达27.7%。     

Crinumin,a chymotrypsin-like but glycosylated serine protease from Crinum asiaticum: Purification and physicochemical characterisation

Plant latex could be a potential source of novel proteases usable in the food and feed industries because of broad substrate specificity with high stability in extreme conditions. Crinumin, a glycosylated serine protease with chymotrypsin-like activity was purified from the latex of Crinumasiaticum using cation-exchange column chromatography. Crinumin shows activity over a wide range of pH (4.5–11.5 and optimum at 8.5), temperature (75 °C and optimum at 70 °C) and is also functional against chaotrophs, organic solvents, and detergents, even after prolonged exposure. The molecular mass (67.7 kDa), extinction coefficient (17.7), isoelectric point (6.9), and numbers of tryptophan (13), tyrosine (24) and cysteine (15 with 7 disulphide bridges) residues were estimated. K_m of the enzyme was 31.7 μM with casein and 5 × 10⁴ μM with N-succinyl-l-phenylalanine-p-nitroanilide. Easy availability of the aqueous latex, simple purification procedure, high yield (33%), stability and activity in adverse conditions makes it applicable for the pharmaceutical and food industries.     

Neriifolin S, a dimeric serine protease from Euphorbia neriifolia Linn.: Purification and biochemical characterisation

A dimeric serine protease Neriifolin S of molecular mass 94 kDa with milk clotting activity has been purified from the latex of Euphorbia neriifolia by anion exchange and size-exclusion chromatography. It hydrolyses peptidyl substrates l-Ala-pNA with highest affinity (K_m of 0.195 mM) and physiological efficiency (K_cat/K_m of 144.5 mM s). Enzyme belongs to the class of neutral proteases with pI value of 6.8, optimal proteolytic activity displayed at pH 9.5 and temperature 45 °C. Its proteolytic activity is strongly stimulated in the presence of Ca⁺² ions and exclusively inhibited by serine protease inhibitors. Enzyme is fairly stable toward chemical denaturants, pH and temperature. The apparent T_m, was found to be 65 °C. Thermal inactivation follow first order kinetics with activation energy (Ea), activation enthalpy (ΔH∗), free energy change (ΔG∗) and entropy (ΔS∗) of 27.54 kJ mol⁻¹, 24.89 kJ mol⁻¹, −82.34 kJ mol⁻¹ and 337.20 J mol⁻¹ K⁻¹.     

地鳖虫提取物抑制乙酰胆碱酯酶活性的研究

采用乙酰胆碱酯酶抑制剂活性筛选模型对地鳖虫不同提取物进行活性筛选。结果表明,地鳖虫浸提最佳溶剂为乙醇,其对AchE的抑制率为27.7%;地鳖虫醇提物萃取最佳溶剂为乙酸乙酯,其对AchE的抑制率为59.78%;地鳖虫萃取物硅胶柱层析最佳流动相为氯仿:甲醇=91:9,其对AchE的抑制率为59.51%。     

Protective effects of four Iranian medicinal plants against free radical-mediated protein oxidation

The role of oxidative protein damages in the pathophysiology of human diseases is currently a topic of considerable interest as oxidised proteins has been implicated in a wide spectrum of clinical disorders. In this study, the antioxidant activities of four Iranian medicinal plants, namely Teucrium polium, Cyperus rotundus, Anethum graveolens and Nasturtium officinale against metal–catalysed protein oxidation were evaluated by pro-oxidant model (Fe²⁺/ascorbate) in rat liver homogenates. The addition of Fe²⁺/ascorbate to the liver homogenate significantly increased the extent of protein oxidation, such as protein carbonyl (PCO) formation and loss of protein-bound sulphydryl (P-SH) groups. Furthermore, the rates of reactive oxygen species (ROS) formation and lipid peroxidation (LPO) were also increased. The plant extracts showed inhibitory effects against PCO formation, P-SH oxidation, ROS formation and LPO to varying degrees. Based on this study, the order of antioxidant activity against protein oxidation was found to be: T. polium > C. rotundus > A. graveolens > N. officinale. The protective effects of each plant extract could be due to its polyphenolic content. In that respect, the T. polium extract with highest polyphenolic content has more antioxidant activity against protein oxidation.     

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.