Preparation and Characterization of Bhant Leaves‐derived Nitrogen‐doped Carbon and its Use as an Electrocatalyst for Detecting Ketoconazole

In this study, the electrocatalytic characteristics of nitrogen‐doped carbon (NDC) prepared from Clerodendrum Infortunatum L leaves on a glassy carbon electrode (GCE) surface was evaluated with regards to its ability to detect the electroactive drug ketoconazole (KCZ). The NDC was prepared by carrying out a simple pyrolysis of dry powder of the leaves at 850 °C. The prepared NDC was characterized using field‐emission scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, X‐ray photoelectron spectroscopy and Brunauer‐Emmett‐Teller analysis, and was then used as an electrode material. The performance of the electrochemical KCZ sensor with the NDC‐modified glassy carbon electrode (NDC/GCE) was found to be optimal when using PBS buffer at pH 3 and a concentration of 0.1 mg/ml of NDC in the conjugate with Nafion polymer. Under these conditions, the NDC/GCE displayed a KCZ detection limit of 3 μM and a linear dependence of its response on KCZ concentration over a wide range of KCZ concentrations from 47 μM to 752 μM (R²=0.9742). These results confirmed the potential of NDC as an electrocatalyst.     

A green protocol for efficient discovery of novel natural compounds: Characterization of new ginsenosides from the stems and leaves of Panax ginseng as a case study

Exploration of new natural compounds is of vital significance for drug discovery and development. The conventional approaches by systematic phytochemical isolation are low-efficiency and consume masses of organic solvent. This study presents an integrated strategy that combines offline comprehensive two-dimensional liquid chromatography, hybrid linear ion-trap/Orbitrap mass spectrometry, and NMR analysis (2D LC/LTQ-Orbitrap-MS/NMR), aimed to establish a green protocol for the efficient discovery of new natural molecules. A comprehensive chemical analysis of the total ginsenosides of stems and leaves of Panax ginseng (SLP), a cardiovascular disease medicine, was performed following this strategy. An offline 2D LC system was constructed with an orthogonality of 0.79 and a practical peak capacity of 11,000. The much greener UHPLC separation and LTQ-Orbitrap-MS detection by data-dependent high-energy C-trap dissociation (HCD)/dynamic exclusion were employed for separation and characterization of ginsenosides from thirteen fractionated SLP samples. Consequently, a total of 646 ginsenosides were characterized, and 427 have not been isolated from the genus of Panax L. The ginsenosides identified from SLP exhibited distinct sapogenin diversity and molecular isomerism. NMR analysis was finally employed to verify and offer complementary structural information to MS-oriented characterization. The established 2D LC/LTQ-Orbitrap-MS/NMR approach outperforms the conventional approaches in respect of significantly improved efficiency, much less use of drug materials and organic solvent. The integrated strategy enables a deep investigation on the therapeutic basis of an herbal medicine, and facilitates new compounds discovery in an efficient and environmentally friendly manner as well.     

Olive-Derived Triterpenes Suppress SARS COV-2 Main Protease: A Promising Scaffold for Future Therapeutics

SARS CoV-2 pandemic is still considered a global health disaster, and newly emerged variants keep growing. A number of promising vaccines have been recently developed as a protective measure; however, cost-effective treatments are also of great importance to support this critical situation. Previously, betulinic acid has shown promising antiviral activity against SARS CoV via targeting its main protease. Herein, we investigated the inhibitory potential of this compound together with three other triterpene congeners (i.e., ursolic acid, maslinic acid, and betulin) derived from olive leaves against the viral main protease (M^pro) of the currently widespread SARS CoV-2. Interestingly, betulinic, ursolic, and maslinic acids showed significant inhibitory activity (IC₅₀ = 3.22–14.55 µM), while betulin was far less active (IC₅₀ = 89.67 µM). A comprehensive in-silico analysis (i.e., ensemble docking, molecular dynamic simulation, and binding-free energy calculation) was then performed to describe the binding mode of these compounds with the enzyme catalytic active site and determine the main essential structural features required for their inhibitory activity. Results presented in this communication indicated that this class of compounds could be considered as a promising lead scaffold for developing cost-effective anti-SARS CoV-2 therapeutics.     

Phytochemical analysis of non-polar solvent extracts of the Wisteria sinensis leaves

A comparative study on the phytochemical composition of the n-hexane and chloroform extracts from Wisteria sinensis leaves collected in June and October is described. Continuous extraction in Soxhlet apparatus, as well as ultrasound-assisted technique, was used for the preparation of the extracts. All the extracts were analysed by GC/MS method. As a result, α-tocopherol was identified as the main component (56%) of the extracts from October leaves, whereas, β-sitosterol was identified as the main compound (47%) in the extracts from the June leaves. Additionally, pure α-tocopherol was isolated from n-hexane extract of the October leaves using column chromatography. A total of 6.25 mg of α-tocopherol was isolated from 1 g of dried leaves. The presence of the vitamin E in extracts from W. sinensis leaves is described here for the first time.     

树脂吸附法分离纯化桑叶总黄酮(Ⅰ)H103树脂对桑叶水提液中总黄酮的吸附性能

采用大孔吸附树脂法从桑叶水提液中分离黄酮类化合物。通过比较10种大孔吸附树脂对桑叶水提液中总黄酮的吸附特性及机理,发现H103树脂对桑叶总黄酮吸附量大、洗脱容易、吸附速度快,是一种良好的桑叶总黄酮吸附剂。实验表明,H103树脂吸附桑叶黄酮的适宜上样浓度为6.05mg/mL,吸附动力学符合Bangham模型,吸附过程符合内扩散模型。     

New lactoyl glycoside quercetin from <Emphasis Type="Italic">Melia azedarach</Emphasis> leaves

In the course of phytochemical investigations of Melia azedarach leaves, a novel cinnamoyl glycoside, cinnamoyl-1-α-L-rhamnoside (1), and a novel acylated quercetin triglycoside, quercetin-3-O-[rhamnosyl 1→6(4″-lactoyl glucoside)]-4′-O-glucoside (2), have been isolated and characterized on the basis of spectroscopic methods, together with the six known flavonoid compounds kaempferol-3-O-rutinoside, 3-O-rhamnoside, quercetin-3-O-rutinoside, 3-O-rhamnoside, and the aglycones quercetin and kaempferol. All isolated compounds have been evaluated for their structures by chromatographic methods, chemical degradation, and UV and NMR spectroscopy. The antioxidant activity of the extract was studied as well. Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 12–14, January–February, 2008.     

固相萃取净化-离子色谱测定不同生长期新鲜烟叶中的7种无机阴离子

目的 为了研究不同生长期新鲜烟叶中无机阴离子的含量和变换规律,建立了一种固相萃取净化/离子色谱方法测定新鲜烟叶中的7种无机阴离子（F-,Cl-,Br-,NO2-,NO3-,SO42-,PO43-）。方法 样品经0.1 mol/L NaOH水溶液超声提取,萃取液经RP1.0cc固相萃取柱净化后,使用AS11-HC（4 mm×250 mm）色谱柱进行分离,以KOH为流动相,梯度洗脱。 结果 7种无机阴离子在0.10-5.0 μg/mL范围内具有较好的线性（r>0.996）,检出限在0.01-0.04 μg/mL之间,定量限在0.04-0.14 μg/mL之间,加标回收率为96.3%～102.1%,相对标准偏差（RSD%）在2.7%~4.8%之间。结论 方法前处理操作简单,7种无机阴离子分离好,检测灵敏准确,可用于不同生长时期新鲜烟叶样品中多种无机阴离子含量的检测分析。     

Antioxidant and toxicological evaluation of a Tamarindus indica L. leaf fluid extract

In the scientific community, there is a growing interest in Tamarindus indica L. leaves, both as a valuable nutrient and as a functional food. This paper focuses on exploring its safety and antioxidant properties. A tamarind leaf fluid extract (TFE) wholly characterised was evaluated for its anti-DPPH activity (IC₅₀ = 44.36 μg/mL) and its reducing power activity (IC₅₀ = 60.87 μg/mL). TFE also exhibited a high ferrous ion-chelating capacity, with an estimated binding constant of 1.085 mol L^? 1 while its influence over nitric oxide production in human leucocytes was irregular. At low concentrations, TFE stimulated NO output, but it significantly inhibited it when there was an increase in concentration. TFE was also classified as a non-toxic substance in two toxicity tests: the acute oral toxicity test and the oral mucous irritability test. Further toxicological assays are needed, although results so far suggest that TFE might become a functional dietary supplement.     

Exploring the Antibacterial and Antibiofilm Efficacy of Silver Nanoparticles Biosynthesized Using Punica granatum Leaves

The current research work illustrates an economical and rapid approach towards the biogenic synthesis of silver nanoparticles using aqueous Punica granatum leaves extract (PGL-AgNPs). The optimization of major parameters involved in the biosynthesis process was done using Box-Behnken Design (BBD). The effects of different independent variables (parameters), namely concentration of AgNO₃, temperature and ratio of extract to AgNO_3, on response viz. particle size and polydispersity index were analyzed. As a result of experiment designing, 17 reactions were generated, which were further validated experimentally. The statistical and mathematical approaches were employed on these reactions in order to interpret the relationship between the factors and responses. The biosynthesized nanoparticles were initially characterized by UV-vis spectrophotometry followed by physicochemical analysis for determination of particle size, polydispersity index and zeta potential via dynamic light scattering (DLS), SEM and EDX studies. Moreover, the determination of the functional group present in the leaves extract and PGL-AgNPs was done by FTIR. Antibacterial and antibiofilm efficacies of PGL-AgNPs against Gram-positive and Gram-negative bacteria were further determined. The physicochemical studies suggested that PGL-AgNPs were round in shape and of ~37.5 nm in size with uniform distribution. Our studies suggested that PGL-AgNPs exhibit potent antibacterial and antibiofilm properties.     

凤凰竹叶黄酮类物质提取条件的优化

天然植物黄酮类物质具有消炎、消肿、降压、降血脂,以及清除氧自由基等多种功能,其提取物质已用于食品、药品、化妆品等产品中。