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At least 19 recordsLinked to original sources
PubMed2002

Photosynthetic responses to water deficit in six Mediterranean sclerophyll species: possible factors explaining the declining distribution of Rhamnus ludovici-salvatoris, an endemic Balearic species.

We sought to explain the declining distribution in the Balearic Islands of the endemic shrub Rhamnus ludovici-salvatoris R. Chodat, by comparing its photosynthetic response to drought with that of several widely distributed, competing Mediterranean species (R. alaternus L., Quercus ilex L., Pistacia lentiscus L., Q. humilis Mill. and P. terebinthus L.). All of the study species, except for the two Rhamnus species, avoided desiccation by rapidly adjusting their stomatal conductance at the onset of drought, and maintaining constant leaf relative water content. The two Rhamnus species showed desiccation-tolerant behavior; i.e., as drought progressed, their predawn leaf relative water content decreased simultaneously with stomatal closure. All four desiccation-avoiding species showed a significant positive correlation between leaf thermal dissipation (estimated by the fluorescence parameter NPQ (non-photochemical quenching)) and the de-epoxidation state of the xanthophyll cycle (DPS). The two Rhamnus species exhibited maximum DPS regardless of treatment, but only R. alaternus increased NPQ in response to drought. Rhamnus ludovici-salvatoris had a high ratio of photorespiration to photosynthesis and a low intrinsic water-use efficiency; traits that are likely to be unfavorable for plant productivity under arid conditions. It also had the lowest DPS and thermal dissipation among the six species. We conclude that the photosynthetic traits of R. ludovici-salvatoris account for its limited ability to compete with other species in the Mediterranean region.

Carbon Dioxide↗
PubMed2026

The complete chloroplast genomes of Rhamnus arguta Maxim. and R. parvifolia Bunge (Rhamnaceae).

The genus Rhamnus L. (Rhamnaceae) has high medicinal, ecological, and ornamental value, but its infrageneric classification remains unclear. Here, we sequenced, assembled, and annotated the complete chloroplast genomes of Rhamnus arguta and R. parvifolia using Illumina sequencing. Both plastomes exhibit the typical quadripartite structure, with lengths of 160,566 bp and 161,243 bp, containing 128 and 129 genes, respectively. Phylogenetic analyses support the monophyly of Rhamnus and its close relationship with Frangula. This study provides genomic resources for further phylogenetic and comparative studies within Rhamnaceae.

Chloroplast genome↗
PubMed2001

In vitro anti-inflammatory effects of quercetin 3-O-methyl ether and other constituents from Rhamnus species.

The anti-inflammatory activities of the isolated flavonoids, quercetin 3-O-methyl ether (1), kaempferol (2), and quercetin (3), of Rhamnus nakaharai, and anthraquinone, frangulin B (4), of Rhamnus formosana, were assessed in vitro by determining their inhibitory effects on the chemical mediators released from mast cells, neutrophils, macrophages, and microglial cells. Compounds 1 - 3 strongly inhibited the release of beta-glucuronidase and lysozyme from rat neutrophils stimulated with formyl-Met-Leu-Phe/cytochalasin B (fMLP/CB). Compound 1 strongly inhibited superoxide anion formation in fMLP/CB or phorbol 12-myristate 13-acetate (PMA)-stimulated rat neutrophils. Compound 1 exhibited potent inhibitory effect on tumor-necrosis factor-alpha ( TNF-alpha) formation in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells while 1 and 4 showed potent inhibitory effects on TNF-alpha formation in LPS/IFN-gamma (interferon-gamma)-stimulated murine microglial cell lines N9.

Animals↗
PubMed2003

Alteration in rhizosphere soil properties of afforested Rhamnus lycioides seedlings in short-term response to mycorrhizal inoculation with Glomus intraradices and organic amendment.

The reestablishment of autochthonous plant species is an essential strategy for recovering degraded areas under semiarid conditions. A field experiment was carried out to assess the short-term effect of two reafforestation methods involving mycorrhizal inoculation and compost addition on soil quality parameters and Rhamnus lycioides seedling growth. The nutrient content (NPK) and enzymatic activities (dehydrogenase, urease, protease-BAA, acid phosphatase and beta-glucosidase) increased and bulk density decreased in the rhizosphere soil with the organic amendment. Biomass C of rhizosphere soil increased by at least 240% with respect to the control soil after mycorrhizal inoculation and the combination of compost addition + mycorrhizal inoculation. Both mycorrhizal inoculation and composted organic residue addition increased R. lycioides seedling growth in the same proportion. In the short term, we conclude that the application of both reafforestation methods not only enhances the establishment of R. lycioides seedlings, but also improves soil quality.

Biomass↗
PubMed1994

Rhamnetin 3-p-coumaroylrhamninoside from Rhamnus petiolaris.

From the berries of Rhamnus petiolaris a new acylated flavonol glycoside was isolated and identified as rhamnetin 3-O-[3""-O-(p-coumaroyl)-alpha-L-rhamnopyranosyl(1-->3)- alpha-L-rhamnopyranosyl(1-->6)]-beta-D-galactopyranoside. Additionally, five known flavonol glycosides, rhamnetin, rhamnazin, quercetin and kaempferol 3-rhamninosides, and quercetin 3-rhamnoside were isolated.

Carbohydrate Sequence↗
PubMed1986

Hypotensive effect of Rhamnus lycioides extracts.

Intravenous administration of a lyophilized hot water extract and various organic solvent extracts of Rhamnus lycioides to normotensive anesthetized Wistar rats produced a lowering of systemic arterial blood pressure. Acute toxicity of the lyophilized extract was studied in mice by intraperitoneal injection. The phytochemical analyses revealed the presence of steroids-triterpenes, catechin tannins, flavonoids, sugars and resins.

Animals↗
PubMed1990

A hypotensive procyanidin-glycoside from Rhamnus lycioides ssp. lycioides.

A lyophilized hot water extract of the aerial parts of Rhamnus lycioides L. (Rhamnaceae) produced a lowering of systemic arterial blood pressure in normotensive anaesthetized Wistar rats. An activity-guided fractionation of the methanolic extract led to the isolation of a tetrameric procyanidin-glycoside which produced a clear dose-dependent hypotensive response (1.5-6 mg/kg i.v.). This principle was characterized using acid hydrolysis, thiolytic degradation and spectroscopic methods. It consisted of four flavanol units with a 2,3-cis configuration and with a O-beta-d-glucosylpyranoside function on the epicatechin terminal unit. The interflavan linkage was (4-8).

Animals↗
PubMed1991

Flavonol and anthraquinone glycosides from Rhamnus formosana.

Two new flavonol triglycosides, and a new anthraquinone glycoside, have been isolated from the roots of Rhamnus formosana. These compounds have been characterized as rhamnazin 3-O-[alpha-L-rhamopyranosyl(1----4)-alpha-L-rhamnopyranosyl(1----6 )]-beta-D-galactopyranoside (rhamnazin 3-isorhamninoside), rhamnocitrin 3-O-isorhamninoside and 1,6,8-trihydroxy-3-methylanthraquinone 1-O-rhamnosyl(1----2)glucoside, respectively.

Anthraquinones↗
PubMed1989

[Studies on isolation, purification and structure of NLC-A of Rhamnus heterophyllus].

A water-soluble glucan, NLC-A, from the roots of Rhamnus heterophyllus Olive was obtained as a homogeneous component as determined by HPLC. NLC-A was shown to compose of D-glucose, and its MW was estimated to be 1.2 x 10(4). Methylation analysis, peroxidation analysis, Smith degradation and reaction with I2-KI showed that NLC-A is a (1----4) linked alpha-D-glucan to which are attached glucosyl side chains at 0-6 of the glucosyl residues of the main chain.

Chemical Phenomena↗
PubMed1993

Frangulin B, an antagonist of collagen-induced platelet aggregation and adhesion, isolated from Rhamnus formosana.

Emodin and its glycoside frangulin B were isolated from the plant Rhamnus formosana. Emodin inhibited the aggregation of rabbit platelets induced by arachidonic acid and collagen, without affecting that by ADP or PAF, while emodin acetate had no any antiplatelet effect. Frangulin B inhibited selectively and concentration-dependently collagen-induced aggregation and ATP release in rabbit platelets, without affecting those induced by arachidonic acid, ADP, PAF and thrombin. Frangulin B also inhibited the platelet aggregation induced by trimucytin which was reported to be a collagen receptor agonist isolated from Trimeresurus muscrosquamatus snake venom. The aggregability of platelets inhibited by frangulin B could be recovered after washing the platelets. Frangulin B also selectively suppressed the thromboxane B2 formation caused by collagen, but not those by arachidonic acid and thrombin. Similarly, the formation of inositol phosphate caused by collagen was also suppressed by frangulin B, while that of PAF or thrombin was not affected. In the presence of PGE1, frangulin B also decreased Mg(2+)-dependent platelet adhesion to collagen. It is concluded that frangulin B may be an antagonist of collagen receptor in platelet membrane.

Amino Acid Sequence↗
PubMed1991

Antihypertensive action of a procyanidin glycoside from Rhamnus lycioides.

The antihypertensive action of a procyanidin glycoside isolated from Rhamnus lycioides aerial parts was studied in spontaneously and renal hypertensive rats. This compound, like 20 micrograms/kg i.v. of captopril, produced a very clear in vivo inhibition of angiotensin I converting enzyme when given at a dose of 3 mg/kg i.v.

Angiotensin-Converting Enzyme Inhibitors↗