Comparative study of the phenolic profile,antioxidant and antimicrobial activities of leaf extracts of five Juniperus L. (Cupressaceae) taxa growing in Turkey

Abstract

The purpose of this study was to conduct a comparative evaluation of some biological properties of methanol and water extracts of leaves of five Juniperus taxa growing in Turkey: J. communis L. var. communis (Jcc), J. communis L. var. saxatilis Pall. (Jcs), J. drupacea Labill. (Jd), J. oxycedrus L. subsp. oxycedrus (Joo), J. oxycedrus L. subsp. macrocarpa (Sibth. & Sm.) Ball. (Jom). The antioxidant properties were examined in vitro; both in the DPPH and in the reducing power tests, Joo methanol extract resulted the most active (IC₅₀?=?0.09?±?0.01mg/mL and ASE/mL?=?2.56?±?0.06). In the TBA assay, Jcs methanol extract exhibited the highest activity (IC₅₀?=?4.39?±?0.47?μg/mL). The extracts displayed bacteriostatic activity against Staphylococcus aureus, and Jd methanol extract resulted the most effective (MIC?=?19.53?μg/mL); no effect on the S. aureus biofilm formation was observed. The extracts resulted non-toxic in the Artemia salina lethality bioassay. Finally, the phenolic profile of the methanol extracts was characterized by HPLC-PDA/ESI-MS.     

Isolation of Volatile Compounds with Repellent Properties against Aedes albopictus (Diptera: Culicidae) Using CPC Technology

The present work describes the use of Centrifugal Partition Chromatography (CPC) for the bio-guided isolation of repellent active volatile compounds from essential oils. Five essential oils (EOs) obtained from three Pinus and two Juniperus species were initially analyzed by gas chromatography–mass spectrometry (GC/MS) and evaluated for their repellent properties against Aedes albopictus. The essential oil from needles of P. pinea (PPI) presented the higher activity, showing 82.4% repellency at a dose of 0.2 μL/cm². The above EO, together with the EO from the fruits of J. oxycedrus subsp. deltoides (JOX), were further analyzed by CPC using the biphasic system n-Heptane/ACN/BuOH in ratio 1.6/1.6/0.2 (v/v/v). The analysis of PPI essential oil resulted in the recovery of (−)-limonene, guaiol and simple mixtures of (−)-limonene/β-pheladrene, while the fractionation of JOX EO led to the recovery of β-myrcene, germacrene-D, and mixtures of α-pinene/β-pinene (ratio 70/30) and α-pinene/germacrene D (ratio 65/45). All isolated compounds and recovered mixtures were tested for their repellent activity. From them, (−)-limonene, guaiol, germacrene-D as well the mixtures of (−)-limonene/β-pheladrene presented significant repellent activity (>97% repellency) against Ae. albopictus. The present methodology could be a valuable tool in the effort to develop potent mosquito repellents which are environmentally friendly.     

Structural analysis and anticomplement activity of a novel homogenous polysaccharide isolated from Juniperus tibetica kom

Abstract

Juniperus tibetica Kom., a common forest species in Tibet, has been traditionally used in Tibetan medicine to treat rheumatic arthritis. In order to investigate the effective substances of J. tibetuca, anticomplent assay-guided fractionation using gradient anion-exchange chromatography and gel permeation chromatography was applied to the crude polysaccharides of the twigs and leaves of J. tibetica and led to the isolation of a homogenous polysaccharide, YB-PS. It exhibited a robust anticomplement activity (CH₅₀: 461?±?10?μg/mL) through the classical pathway of complement system activation by targeting complement components C1q, C3, C4 and C5. The structure of YB-PS was studied by monosaccharide composition and methylation analyses, 1?D, 2?D NMR data and scanning electron microscope. The results indicated that YB-PS was composed of Ara, Gal, and Glc with a molar ratio of 5.8:3.0:1.2. Its backbone was comprised of 1,3-linked α-Araf, 1,3,5-linked α-Araf, 1,2,4-linked α-Galp, and 1,3-linked α-Glcp with terminal α-Araf, β-Galp and 1,4-linked β-Galp as branches. YB-PS was found to have a sheet structure with smooth surface. This study provided scientific foundation for YB-PS as a potential complement inhibitor to treat diseases involved with excessive activation of the complement system.     

A Study on the In Vitro Antioxidant Activity of Juniper (Juniperus communis L.) Fruit Extracts

Abstract

This study aimed at evaluating the in vitro antioxidant activity of water and ethanol extracts of juniper (Juniperus communis L., Family Cupressaceae) fruit. The antioxidant properties of both Juniper extracts were studied using different antioxidant assays, including reducing power, free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities. Both the water and the ethanol extracts exhibited strong total antioxidant activity. The concentrations of 20, 40, and 60 µg/mL of water and ethanol extracts of juniper fruit showed 75%, 88%, 93%, 73%, 84%, and 92% inhibition on peroxidation of linoleic acid emulsion, respectively. On the other hand, 60 µg/mL of standard antioxidant such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and α‐tocopherol exhibited 96, 96, and 61 inhibitions on peroxidation of linoleic acid emulsion, respectively. However, both extracts of juniper had effective reducing power, free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities at these same concentrations (20, 40, and 60 µg/mL). Those various antioxidant activities were compared to BHA, BHT, and α‐tocopherol as standard antioxidants. In addition, total phenolic compounds in both aqueous and ethanolic juniper extracts were determined as gallic acid equivalents. Accordingly, these results indicate that juniper has in vitro antioxidant properties and these may be major reasons for the inhibition of lipid peroxidation properties.     

Five New Sesquiterpenes from the Heartwood of Juniperus Squamata Lamb

Extracts of the heartwood of Juniperus squamata Lamb. var. morrisonicola (Hay.) Li and Keng contain the known constituents 8,14-cedranoxide, 8,14-cedranolide, cedrol, β-sitosterol, widdrol, 7-oxototarol, procerin, 8,14-cedranediol, hinokiol, sugiol, hinokiic acid, cedrolic acid, and five new sesquiterpenoids, epicedranediol, 4-ketocedrol, 3β-hydroxycedrol, isocedrolic acid, and β-chamigrenic acid. These new sesquiterpenes were identified by spectroscopic data and chemical correlations.     

The Composition of Essential Oils from Various Parts of Juniperus foetidissima

Water-distilled oils from the leaf, cone berry, seedless cone berry, seed, and branch of Juniperus foetidissima were analyzed by GC/MS. The main components of the leaf oil were found as -thujone and cedrol. Sabinene was the major component in the essential oil of cone berries. Sabinene, -thujone, and abietal were the main components of the seed and seedless cone berry oils. In the branch oil -pinene was the major component.     

Bioactivity-guided isolation of new antiproliferative compounds from Juniperus foetidissima Willd.

Based on a literature survey on cytotoxic medicinal plants, Juniper species were identified as interesting source of antitumor compounds. Using bioassay-guided fractionation against Caov-4 cancer cells on acetone extract of leaves and branchlets of Juniperus foetidissima led to the isolation of a new 3H-benzofuaran-2-one: 4-methyl-3-methoxy-3H-benzofuaran-2-one (1), a new sesquiterpene: 4,9(α)-dihydroxy-nardosin-6-en (2) and an already known labdane-type diterpene: 15-hydroxy-8(17),13(E)-labdadiene-19-carboxilic acid (3). Compounds 1–3 exhibited cytotoxic effects, with moderate cytotoxicity against the EJ-138 bladder and CAOV-4 ovary cancer cell lines.     

Green synthesis and characterization of silver nanoparticles using Juniperus communis leaf extract: Catalytic activity in real-outdoor conditions and electrochemical properties

The present study investigates the green synthesis of stable silver nanoparticles using Juniperus communis leaf aqueous extract at room temperature. Synthesized silver nanoparticles (AgNPs) were characterized with different techniques such as UV–vis spectroscopy, Fourier transforms infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM-EDAX) and electrochemical method. Photocatalytic and anti-bacterial activities of synthesized AgNPs are evaluated based on the obtained result showed an efficient inhibition growth for gram negative P. Aeruginosa, E. Coli, and gram positive bacteria S.aureus. The AgNPs exhibited an excellent photocatalytic activity toward the degradation of methylene blue both indoor and outdoor, under sunlight, an efficiency of 95% was achieved. As an easy and environmentally friendly process, AgNPs based on Juniperus communis leaf extract could be applied for the degradation of pollutants and wastewater treatment.     

The Structure of Suginal from the Wood of Juniperus Formosana Hayata

The detailed investigation of the acetone extract from the wood of Juniperus formosana Hayata gave a new diterpene aldehyde which was elucidate as suginal on the basis of chemical and spectroscopic evidence.