Recent advances in application and progress of advanced materials as adsorbents in sample preparation for plant growth regulators.

Plant growth regulators are a class of physiologically active substances that could modify or regulate basic physiological processes in the plant and defense against abiotic and biotic stresses, including natural plant growth regulators and synthetic ones. Different from natural plant growth regulators with low content and high cost of extraction in plants, synthetic ones can be produced in large-scale production and widely used in agriculture for increasing and securing yield and quality of the harvested produce. However, like pesticides, the abuse of plant growth regulators will have negative impacts on human beings.

Purification, characterization and antioxidant activities of a polysaccharide from the roots of Lilium davidii var. unicolor Cotton.

A polysaccharide (LPR) was separated from the roots of Lilium davidii var. unicolor Cotton with hot water extraction, ethanol precipitation, and purification by anion-exchange and gel-permeation chromatography. LPR was characterized.

Structural characterization, antioxidant and antibacterial activities of two heteropolysaccharides purified from the bulbs of Lilium davidii var. unicolor Cotton.

Two heteropolysaccharides, BHP-1 and BHP-2, were separated and purified from the edible bulbs of Lilium davidii var. unicolor Cotton by anion-exchange and gel-permeation chromatography. The primary structural characteristics of BHP-1 and BHP-2 were investigated by Congo red test, X-ray diffractometry (XRD) analysis, IR, GC and NMR.

Main Allelochemicals from the Rhizosphere Soil of (Decne.) Sch. Bip. and Their Effects on Plants' Antioxidase Systems.

Allelochemicals are the media of allelopathy and form the chemical bases of plant-environment interactions. To determine true allelochemicals and their autotoxic effects, seven compounds were isolated and identified from sampled rhizosphere soil of cultivated . Of these; costunolide (), dehydrocostus lactone () and scopoletin () showed significant inhibition on seedling growth in a concentration-dependent manner.

Bio-guided isolation of plant growth regulators from allelopathic plant-: phyto-selective activities and mechanisms.

Natural pesticides are the subject of growing interest, as the overuse of synthetic pesticides severely threatens the safety of humans and the eco-environment. Allelopathic plants can release plentiful secondary metabolites as natural plant growth regulators to affect the growth of neighboring plants. Bio-guided isolation of the aerial waste part of typical allelopathic plant- led to six active compounds being produced, including ginsenoside Rg (1), ginsenoside Re (2), luteolin (3), luteolin-5--glucoside (4), ginsenoside Rb (5) and lobetyolin (6).

Structural basis, chemical driving forces and biological implications of flavones as Cu(II) ionophores.

A main biochemical property of cancer cells, compared with normal cells, is altered redox status including increased levels of copper to maintain their malignant phenotypes. Thus, increasing copper accumulation, by using ionophores, to disrupt abnormal redox homeostasis of cancer cells may be an important anticancer strategy. Naturally occurring molecules with extraordinarily diverse chemical scaffolds are an important source of inspiration for developing copper ionophores.

Codonopilate A, a Triterpenyl Ester as Main Autotoxin in Cultivated Soil of Codonopsis pilosula (Franch.) Nannf.

Codonopilate A (1), a triterpenyl ester, was isolated from monocultivated soil of annual Codonopsis pilosula and identified as the main autotoxin. The yield ratio of codonopilate A in dried soil was calculated as 2.04 μg/g.

Antifungal activity of umbelliferone derivatives: Synthesis and structure-activity relationships.

Umbelliferone was an important allelochemical with a wide spectrum bioactivity. In our previous study, C7 hydroxy in the backbone of umbelliferone was identified to be responsible for its phytotoxicity and the targeted modification of the above site could lead to the phytotoxicity loss. In view of this, a series of hydroxycoumarins and C7 O-substituted umbelliferone derivatives were efficiently synthesized to evaluate their antifungal activity against four phytopathogenic fungi.

Cycloartane-type triterpenoids from Astragalus hoantchy French.

A new cycloartane-type triterpenoid, 3β-acetoxy-9β,19-cyclolanost-24E-ene-1α,16β-diol-27-O-β-d-glucopyranoside (1), together with three known ones (2-4) were isolated from the aerial parts of Astragalus hoantchy. The structure of compound 1 was elucidated by detailed spectroscopic analyses including 1D and 2D NMR, HRESIMS, and IR experiments. All of the four compounds were isolated from A.

Flavoniods from aerial parts of Astragalus hoantchy.

Four new flavonoids, astragaisoflavans A-D (1-4), along with thirteen known ones (5-17) were isolated from the aerial parts of Astragalus hoantchy. Their structures were established by the extensive spectroscopic analyses including one- and two-dimensional NMR, HRESIMS, IR, and UV results. The absolute configurations of 1-4 were deduced based on circular dichroism.

Synthesis of N-substituted phthalimides and their antifungal activity against Alternaria solani and Botrytis cinerea.

As organosulfur and organophosphorus agents, phaltane and phosmet are facing great challenges for the environmental contamination, mammalian toxicity and increasing resistance with long term use. It is efficient and meaningful to develop phthalimide-based alternatives with non-sulfur and non-phosphorus groups. A series of N-substituted phthalimides were synthesized and their antifungal activity against two disastrous phytopathogenic fungi, Alternaria solani and Botrytis cinerea was evaluated in vitro.

Allelochemicals from the Rhizosphere Soil of Cultivated Astragalus hoantchy.

Astragalus hoantchy, a widely cultivated medicinal plant species in traditional Chinese and Mongolian medicine, has been often hampered by replant failure during cultivation, like many other herbs of the genus Astragalus. Root aqueous extracts of Astragalus herbs were reported to exhibit allelopathic activity against other plants and autotoxic activity on their own seedlings, but the allelochemicals released by Astragalus plants have not been specified so far. Ten compounds were isolated from the rhizosphere soil extract of cultivated A.

Phytotoxicity of umbelliferone and its analogs: Structure-activity relationships and action mechanisms.

Two coumarins, umbelliferone and daphnoretin, were isolated from roots of Stellera chamaejasme L; the former had been identified as one of the main allelochemicals in our previous studies. Both of them have the skeleton of 7-hydroxycoumarin, but showed different phytotoxic effects. Umbelliferone and its analogs were then prepared to investigate the structure-activity relationship of hydroxycoumarins and screened for phytotoxicity.

Isolation, Identification, and Autotoxicity Effect of Allelochemicals from Rhizosphere Soils of Flue-Cured Tobacco.

Autotoxicity, defined as a deleterious allelopathic effect among individuals of the same plant species, is considered as one of the factors that contributes to replant failure. Tobacco, as an important cultured and economic crop over the world, has been often hampered by replant failure. In view of the seriousness of this problem, the allelochemicals of flue-cured tobacco and their allelopathic effects were investigated.

Phylogenic diversity and tissue specificity of fungal endophytes associated with the pharmaceutical plant, Stellera chamaejasme L. revealed by a cultivation-independent approach.

The fungal endophytes associated with medicinal plants have been demonstrated as a reservoir with novel natural products useful in medicine and agriculture. It is desirable to explore the species composition, diversity and tissue specificity of endophytic fungi that inhabit in different tissues of medicinal plants. In this study, a culture-independent survey of fungal diversity in the rhizosphere, leaves, stems and roots of a toxic medicinal plant, Stellera chamaejasme L.

Isolation and characterization of bacteria from the rhizosphere and bulk soil of Stellera chamaejasme L.

This study is the first to describe the composition and characteristics of culturable bacterial isolates from the rhizosphere and bulk soil of the medicinal plant Stellera chamaejasme L. at different growth stages. Using a cultivation-dependent approach, a total of 148 isolates showing different phenotypic properties were obtained from the rhizosphere and bulk soil.

Allelochemicals in the rhizosphere soil of Euphorbia himalayensis.

Weed infestation has been known to cause considerable reductions in crop yields, thereby hindering sustainable agriculture. Many plants in genus Euphorbia affect neighboring plants and other organisms by releasing chemicals into the environment. In view of the serious threat of weeds to agriculture, the allelochemicals of Euphorbia himalayensis and their allelopathic effects were investigated.

Influence of side chain structure changes on antioxidant potency of the [6]-gingerol related compounds.

[6]-Gingerol and [6]-shogaol are the major pungent components in ginger with a variety of biological activities including antioxidant activity. To explore their structure determinants for antioxidant activity, we synthesized eight compounds differentiated by their side chains which are characteristic of the C1-C2 double bond, the C4-C5 double bond or the 5-OH, and the six- or twelve-carbon unbranched alkyl chain. Our results show that their antioxidant activity depends significantly on the side chain structure, the reaction mediums and substrates.

Tailoring 3,3'-dihydroxyisorenieratene to hydroxystilbene: finding a resveratrol analogue with increased antiproliferation activity and cell selectivity.

Four novel compounds were designed by "tailoring" 3,3'-dihydroxyisorenieratene (a natural carotenoid) based on an isoprene unit retention truncation strategy. Among them, the smallest molecule 1 (2,3,6,2',3',6'-hexamethyl-4,4'-dihydroxy-trans-stilbene) was concisely synthesized in a one-pot Stille-Heck tandem sequence, and surfaced as a promising lead molecule in terms of its selective antiproliferative activity mediated by blocking the NCI-H460 cell cycle in G1 phase. Additionally, theoretical calculations and cell uptake experiments indicate that the unique polymethylation pattern of compound 1 significantly induces a conformational change shift out of planarity and increases its cell uptake and metabolic stability.

[Study on chemical constituents from petroleum ether-soluble parts of cones of Platycladus orientalis].

Objective: To study chemical constituents from petroleum ether-soluble parts of cones of Platycladus orientalis.

Methods: The compound were isolaeed by repeated column chromatography of silica gel and Sephadex LH-20. The structures were elucidated by physicochemical properties and spectrum analysis.

Hypohalous acid-mediated halogenation of resveratrol and its role in antioxidant and antimicrobial activities.

The reactions of resveratrol with proinflammatory oxidants including hypochlorous and hypobromous acids in phosphate-buffered saline/methanol solution were carried out and eight halogenated resveratrol derivatives differing in the number and position of halogen atoms, and the configuration of double bond were obtained. Halogenation of resveratrol took place only at the aromatic A ring, and interestingly, the halogenation increased antioxidant activity of this parent molecule in the 2,2'-azobis(2-amidinopropane) hydrochloride-induced RBC haemolysis model. Additionally, antimicrobial activity of the derivatives against Gram-positive bacteria, Gram-negative bacteria and fungi were tested, and toward Candida albicans, 2-chloro-resveratrol and 2-bromo-resveratrol were more active than the unmodified form and the reference compound fluconazole.

Synthesis and antioxidant activity of hydroxylated phenanthrenes as cis-restricted resveratrol analogues.

Five hydroxylated phenanthrenes as "cis-configuration-fixed" resveratrol analogues differing in the number and position of the hydroxyl groups were designed and synthesized. Their antioxidant activity was studied by ferric reducing antioxidant power, 2,2-diphenyl-1-picrylhydrazyl free radical-scavenging, and DNA strand breakage-inhibiting assays, corresponding to their electron-donating, hydrogen-transfer and DNA-protecting abilities, respectively. In the above assays, their activity depends significantly on the number and position of the hydroxyl groups, and most of them are more effective than resveratrol.