Evaluation of Antioxidant,Antibacterial and Enhancement of Antibiotic Action by Punica granatum Leaves Crude Extract and Enriched Fraction against Multidrug-Resistant Bacteria

The aim of this study was to evaluate the phytochemical composition, antioxidant, and antimicrobial potential of crude extract and fractions of Punica granatum leaves. The extract was produced by turbo extraction, after which hexanic, ethyl acetate, and aqueous fractions were obtained by partitioning. The chemical analyses were performed by thin layer chromatography and high-performance liquid chromatography, and the antioxidant activities were assayed by DPPH^. and ABTS^.+. Minimal inhibitory and bactericidal concentrations (MIC/MBC) were applied to twenty-two bacteria. Most strains susceptible to extract/fractions and resistant to antibiotics were selected, and ampicillin, azithromycin, ciprofloxacin, and gentamicin were associated with the ethyl acetate fraction (EAF) against multidrug-resistant strains in modulatory and checkboard models. The data from chromatographic analyses showed flavonoids and tannins in the extract, as well as the enrichment of EAF in phenols, mainly flavonoids. The flavonoids were connected to the electron transfer activity demonstrated in the DPPH^. and ABTS^.+ assays. Gram-positive strains are more susceptible to EAF. The subinhibitory concentrations of P. granatum enhanced the antimicrobial activity of the agents and reduced the EAF individual MIC, and the combination of EAF and antibiotics demonstrated a synergistic effect. These results present a promising approach for developing a therapy in which antioxidant extracts and fractions can be used in combination with antibiotics.     

StructureActivity Relationships of Antimicrobial Gallic Acid Derivatives from Pomegranate and Acacia Fruit Extracts against Potato Bacterial Wilt Pathogen

Bacterial wilts of potato, tomato, pepper, and or eggplant caused by Ralstonia solanacearum are among the most serious plant diseases worldwide. In this study, the issue of developing bactericidal agents from natural sources against R. solanacearum derived from plant extracts was addressed. Extracts prepared from 25 plant species with antiseptic relevance in Egyptian folk medicine were screened for their antimicrobial properties against the potato pathogen R. solancearum by using the disc‐zone inhibition assay and microtitre plate dilution method. Plants exhibiting notable antimicrobial activities against the tested pathogen include extracts from Acacia arabica and Punica granatum. Bioactivity‐guided fractionation of A. arabica and P. granatum resulted in the isolation of bioactive compounds 3,5‐dihydroxy‐4‐methoxybenzoic acid and gallic acid, in addition to epicatechin. All isolates displayed significant antimicrobial activities against R. solanacearum (MIC values 0.5–9 mg/ml), with 3,5‐dihydroxy‐4‐methoxybenzoic acid being the most effective one with a MIC value of 0.47 mg/ml. We further performed a structure–activity relationship (SAR) study for the inhibition of R. solanacearum growth by ten natural, structurally related benzoic acids.     

Analysis of ellagic acid in pomegranate rinds by capillary electrophoresis and high-performance liquid chromatography

Two novel methods for the analysis of ellagic acid in pomegranate (Punica granatum) rinds are proposed. Capillary electrophoresis (CE) was performed in a bare fused-silica capillary using a buffer solution of tri(hydroxymethyl)aminomethane:potassium dihydrogen phosphate (pH 8.4) with an applied voltage of 20 kV and UV detection at 254 nm. HPLC analysis was performed with a Zobax SB C(18) column and a mobile phase consisting of methanol:ethyl acetate:potassium dihydrogen phosphate: phosphoric acid at a flow rate of 1.0 mL/min. Under optimised conditions, the HPLC retention and the CE migration times for ellagic acid were 10.32 and 12.23 min, respectively. Calibration curves of peak area vs. concentration gave correlation coefficients of 0.9999 for HPLC and 0.9990 for CE. The detection limits for HPLC and CE were 2.8 and 2.2 microg/mL, respectively. Average recoveries were 98.32 +/- 1.2% for HPLC and 96.52 +/- 2.8% for CE. Both methods were shown to be suitable for the determination of ellagic acid in pomegranate rinds extraction; however, the CE method required less solvent and gave better column efficiency, whilst the HPLC provided superior precision.     

太行山石质山地石榴中幼龄林林地蒸散规律研究

利用波文比-能量平衡方法测定了太行山石质山地石榴林地蒸散量的日变化和月变化,并且计算出各物候期的蒸散量．结果表明,石榴在中午关闭气孔,以减少生理蒸腾．石榴林地蒸散量与净辐射呈显著线性相关,回归方程为Y=0．0029X-0．1449,相关系数R为0．9．石榴林地从萌芽期到落叶期的总蒸散量为424．08mm．其中,开花-果实成熟期林地蒸散量最大,占生长季节总蒸散量的64．59％．石榴林地每年需要补充灌溉两次,一次在萌芽期,一次在开花前期．     

Antibacterial activity of Punica granatum L. and Areca nut (P.A) combined extracts against some food born pathogenic bacteria

The antibacterial effects of combined extracts of Punica granatum L. and Areca nut (P.A) against resistant bacteria, a gram-positive bacterium, Staphylococcus aureus and three gram-negative bacteria, Escherichia coli, Salmonella, and Enterobacter aerogenes, in individual and biofilm forms was studied. Antibacterial activity was studied using disk diffusion method, microbroth dilution, and microtiter plate methods. Given the disc diffusion test (Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC)), the extracts had inhibitory effects on the individual forms of bacteria. However, the ethanolic extract had greater effectiveness than the methanolic extract. Generally, ethanol efficiently extracts flavonoids and their glycosides, catechol and tannins. This fact due to the ethanol polarity that is equal 0.654. The results indicated that the ability of extracts in inhibiting the formation of biofilms, destruction of biofilms, and prevention of metabolic activity of bacteria had a direct relationship with concentration and the highest inhibitory was seen on Staphylococcus aureus (98.98%), Staphylococcus aureus (94.98%), and Enterobacter aerogenes (88.55%). Based on the results, the P.A. combined extract can be used as an alternative combination with the ability to inhibit antibiotic-resistant bacteria in single and biofilm forms.     

石榴组织培养研究进展

石榴是中国常见的栽培果树之一,其果实具有较高的食用和药用价值。每年除了供应国内市场以外,还大量出口。在当前农业结构调整及加入世贸组织的形势下,种植和发展石榴具有广阔的市场前景。传统的分株、扦插及压条繁殖方式已不能满足石榴种苗市场生产的需求,通过组织培养快繁技术,可望在较短时间内,生产大量优质种苗。通过查阅相关文献资料,对石榴组织培养过程中外植体选择、灭菌和消毒,愈伤组织的诱导,试管苗的分化、扩繁、生根、炼苗及移栽进行综述,提出了制约石榴组织培养规模化生产的问题,并对石榴组织培养的发展前景进行了展望。     

石榴类黄酮代谢产物的研究进展

石榴（Punica granatum）是一种栽培历史悠久且营养价值很高的水果, 我国已形成了河南荥阳和开封、陕西临潼、山东枣庄、安徽怀远、四川会理、云南蒙自和新疆叶城8大石榴主产区。迄今为止, 从石榴果汁、果皮和叶片中共检测出类黄酮多达33种, 其中包括6种黄烷醇、1种黄烷酮苷、2种黄酮醇、3种黄酮醇苷、3种黄酮、5种黄酮苷、1种二氢黄酮醇苷、3种花青素苷元和9种花青素苷, 这些化合物在保健食品和医疗应用中具有重要作用。该文对石榴果实、叶片和花瓣中所含类黄酮的组成、含量、检测方法及药理等方面的研究现状进行了综述, 建议今后应加强石榴果实中类黄酮的快速分析、半制备和制备分离、定量分析方法以及种质资源评价、叶和花中的活性成分鉴定等方面的研究, 以促进对石榴活性成分及其功能的深入研究和利用。     

Limonoids with an Oxygen Bridge between C(1) and C(29) from the Seeds of a Krishna Mangrove,Xylocarpus granatum

Ten limonoids, named granatumins L–U ( 1 – 10 , resp.), were isolated from the seeds of an Indian mangrove, Xylocarpus granatum, collected in the estuary of Krishna, Andhra Pradesh. The structures of these compounds were established on the basis of spectroscopic data. The relative configuration of granatumin L ( 1 ) was confirmed by a single‐crystal X‐ray diffraction analysis. Granatumins L–T ( 1 – 9 , resp.) belong to the small group of limonoids with an oxygen bridge between C(1) and C(29), while granatumin U ( 10 ) is a 28‐Me‐oxidized mexicanolide. This is the first report of limonoids with an O‐bridge between C(1) and C(29) from the Indian X. granatum. The pronounced structural diversity of limonoids from this mangrove might originate from environmental factors.     

石榴果色合成相关基因CHS和CHI的表达特性分析

花色苷是类黄酮家族中重要的一类次生代谢产物,对果实呈色起重要作用。CHS (查尔酮合成酶)和CHI (查尔酮异构酶)为花色苷合成提供了前体物质,是花色苷合成所不可或缺的。利用RT-PCR和RACE方法,本研究从石榴果皮中克隆了与花色苷合成相关的CHS基因和CHI基因的cDNA全长,同时采用qRT-PCR研究了这两个基因在三个不同色泽石榴品种‘红宝石’、‘水晶甜’、‘墨石榴’发育期内的表达模式,并分析了果皮花色苷含量变化与基因转录水平的关系。结果表明,石榴中CHS和CHI基因cDNA全长分别为1 197 bp和693 bp,分别编码398和230个氨基酸,命名为PgCHS和PgCHI,在GenBank中的登录号分别为KF841615和KF841616。在氨基酸水平上,Pg CHS与荔枝、葡萄、山竹等果树的同源性达到90%以上。Pg CHI与果树中龙眼、梨、美洲葡萄、桑树等同源性达到70%以上。qRT-PCR结果显示,CHS和CHI基因的表达模式随色泽发育期和品种不同而有差异。在‘红宝石’石榴中,该两个基因都有前期和后期两个表达高峰期;而‘水晶甜’石榴中这两个基因的表达高峰期均出现在中后期;‘墨石榴’发育初期时CHS和CHI的表达量最高,以后的表达量都较低。同一品种内,CHS和CHI的表达具有协同性,两者的协同性表达有利于花色苷及其他类黄酮相关产物的合成。3个品种中CHS和CHI基因的表达与花色苷的积累并不一致。     

Xylomexicanins C and D,New Mexicanolide-Type Limonoids from Xylocarpus granatum

Cell-free extracts of petioles of Arctium lappa catalyzed enantioselective formation of (+)-secoisolariciresinol [about 20% enantiomer excess (e.e.)] from achiral coniferyl alcohol in the presence of NADPH and H₂O₂. This is the first report of an enzymatic reaction to afford (+)-secoisolariciresinol enantioselectively.