Bioactive compounds from Artemisia dracunculus L. activate AMPK signaling in skeletal muscle.

An extract from Artemisia dracunculus L. (termed PMI-5011) improves glucose homeostasis by enhancing insulin action and reducing ectopic lipid accumulation, while increasing fat oxidation in skeletal muscle tissue in obese insulin resistant male mice. A chalcone, DMC-2, in PMI-5011 is the major bioactive that enhances insulin signaling and activation of AKT. However, the mechanism by which PMI-5011 improves lipid metabolism is unknown. AMPK is the cellular energy and metabolic sensor and a key regulator of lipid metabolism in muscle. This study examined PMI-5011 activation of AMPK signaling using murine C2C12 muscle cell culture and skeletal muscle tissue. Findings show that PMI-5011 increases Thr172-phosphorylation of AMPK in muscle cells and skeletal muscle tissue, while hepatic AMPK activation by PMI-5011 was not observed. Increased AMPK activity by PMI-5011 affects downstream signaling of AMPK, resulting in inhibition of ACC and increased SIRT1 protein levels. Selective deletion of DMC-2 from PMI-5011 demonstrates that compounds other than DMC-2 in a "DMC-2 knock out extract" (KOE) are responsible for AMPK activation and its downstream effects. Compared to 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) and metformin, the phytochemical mixture characterizing the KOE appears to more efficiently activate AMPK in muscle cells. KOE-mediated AMPK activation was LKB-1 independent, suggesting KOE does not activate AMPK via LKB-1 stimulation. Through AMPK activation, compounds in PMI-5011 may regulate lipid metabolism in skeletal muscle. Thus, the AMPK-activating potential of the KOE adds therapeutic value to PMI-5011 and its constituents in treating insulin resistance or type 2 diabetes.

Compounds leached from quinoa seeds inhibit matrix metalloproteinase activity and intracellular reactive oxygen species.

OBJECTIVE: Quinoa (Chenopodium quinoa Willd.) is a seed crop rich in bioactive compounds including phytoecdysones (especially 20-hydroxyecdysone, 20HE), polyphenols, proteins and essential fatty acids. We previously reported a method to leach and concentrate quinoa bioactives into a complex phytochemical mixture termed quinoa leachate (QL). Here, we aimed to determine the effect of QL and its chemically distinct fractions on five biochemical endpoints relevant to skin care applications: (i) cell viability, (ii) matrix metalloproteinase (MMP) mRNA expression, (iii) MMP enzymatic activity, (iv) tyrosinase enzymatic activity and (v) intracellular reactive oxygen species (ROS) production. METHODS: Quinoa leachate was fractionated and chemically characterized using column chromatography and liquid chromatography-mass spectrometry (LC-MS). Cell viability was determined using a MTT assay in four mammalian cell lines. MMP-1 mRNA expression was assessed in human dermal fibroblasts (HDF) via qRT-PCR. The enzymatic activity of MMP-9 and tyrosinase was measured using fluorometric and colorimetric in vitro assays, respectively. Lipopolysaccharide (LPS)-induced ROS production was determined in human dermal fibroblasts by fluorescence intensity of an oxidant-sensitive probe. RESULTS: Quinoa leachate was separated into three fractions: (i) carbohydrate-rich fraction (QL-C; 71.3% w/w of QL); (ii) phytoecdysone, polyphenol and protein-rich fraction (QL-P, 13.3% w/w of QL); (iii) oil-rich fraction (QL-O, 10.8% w/w of QL). QL did not reduce cell viability in any of the four cell lines tested. QL, QL-P and QL-O each significantly inhibited MMP-1 mRNA expression in HDF at a concentration of 5 µg mL(-1) . QL and QL-P also significantly inhibited MMP-9 enzymatic activity, whereas QL-P demonstrated significant tyrosinase enzymatic inhibition. Furthermore, QL, QL-P, QL-O and 20HE significantly inhibited intracellular ROS production. CONCLUSION: This study is the first to demonstrate the MMP, tyrosinase and ROS inhibiting properties of multiple different phytochemical components derived from quinoa seeds. Our work indicates that quinoa phytochemicals may play a role in the treatment and prevention of skin ageing through a multiplicity of effects.

Antihyperglycemic activity of Tarralin, an ethanolic extract of Artemisia dracunculus L.

The studies reported here were undertaken to examine the antihyperglycemic activity of an ethanolic extract of Artemisia dracunculus L., called Tarralin in diabetic and non-diabetic animals. In genetically diabetic KK-A(gamma) mice, Tarralin treatment by gavage (500 mg/kg body wt./day for 7 days) lowered elevated blood glucose levels by 24% from 479+/-25 to 352+/-16 mg/dl relative to control animals. In comparison, treatment with the known antidiabetic drugs, troglitazone (30 mg/kg body wt./day) and metformin (300 mg/kg body wt./day), decreased blood glucose concentrations by 28% and 41%, respectively. Blood insulin concentrations were reduced in the KK-A(gamma) mice by 33% with Tarralin, 48% with troglitazone and 52% with metformin. In (STZ)-induced diabetic mice, Tarralin treatment, (500 mg/kg body wt./day for 7 days), also significantly lowered blood glucose concentrations, by 20%, from 429+/-41 to 376+/-58 mg/dl relative to control. As a possible mechanism, Tarralin was shown to significantly decrease phosphoenolpyruvate carboxykinase (PEPCK) mRNA expression by 28% in STZ-induced diabetic rats. In non-diabetic animals, treatment with Tarralin did not significantly alter PEPCK expression, blood glucose or insulin concentrations. The extract was also shown to increase the binding of glucagon-like peptide (GLP-1) to its receptor in vitro. These results indicate that Tarralin has antihyperglycemic activity and a potential role in the management of diabetic states.

Tracer studies with 13C-labeled carbohydrates in cultured plant cells. Retrobiosynthetic analysis of chelidonic acid biosynthesis.

The biosynthesis of chelidonic acid was studied in cell suspension cultures of Leucojum aestivum. Cell cultures were supplied with [U-13C]glucose, [l-13C]glucose or [U-13Cs]ribose/ribulose in standard medium containing unlabeled glucose. 13C labeling patterns of amino acids obtained by hydrolysis of biomass were determined by NMR spectroscopy and compared to the labeling pattern of chelidonic acid. The data document the incorporation of a contiguous 4-carbon fragment derived from the pentose phosphate pool into chelidonic acid. This suggests a biosynthetic pathway involving the condensation of phosphoenolpyruvate with a pentose phosphate followed by dehydration, dehydrogenation, ring closure and decarboxylation conducive to the loss of C-5 of the pentose precursor.

Use of plant roots for phytoremediation and molecular farming.

Alternative agriculture, which expands the uses of plants well beyond food and fiber, is beginning to change plant biology. Two plant-based biotechnologies were recently developed that take advantage of the ability of plant roots to absorb or secrete various substances. They are (i) phytoextraction, the use of plants to remove pollutants from the environment and (ii) rhizosecretion, a subset of molecular farming, designed to produce and secrete valuable natural products and recombinant proteins from roots. Here we discuss recent advances in these technologies and assess their potential in soil remediation, drug discovery, and molecular farming.

Synthesis and separation of potential anticancer active dihalocephalomannine diastereomers from extracts of Taxus yunnanensis.

Two diastereomeric 2",3"-dibromo cephalomannines and their two corresponding 7-epimers were obtained by treatment of extracts of Taxus yunnanensis with bromine solution under mild conditions. Treatment of the same extract with chlorine solution yielded four diasteromeric 2",3"-dichlorocephalomannines, with no 7-epimers. The diastereomeric mixtures were separated into the individual components by preparative HPLC on C18 reversed-phase silica gel. A more efficient analytical separation was obtained on a pentafluorophenyl-bonded phase. These reaction products were isolated and fully identified spectroscopically. Slight differences were observed in the NMR spectra of the 7-epimers when compared to their 7 beta-OH analogues. On the basis of a comparison of physicochemical data, the bromo compounds were identified as (2"R,3"S)-dibromo-7-epi-cephalomannine (3), (2"S,3"R)-dibromo-7-epi-cephalomannine (4), (2"R,3"S)-dibromocephalomannine (5), and (2"S,3"R)-dibromocephalomannine (6), and the chloro compounds as (2"R,3"R)-dichlorocephalomannine (7), (2"S,3"S)-dichlorocephalomannine (8), (2"R,3"S)-dichlorocephalomannine (9), and (2"S,3"R)-dichlorocephalomannine (10). Cytotoxic activity was tested against the NCI 60 human tumor cell line panel in comparison with paclitaxel (1), and encouraging results were obtained in some cases.

Immunoassays for the quantitative determination of colchicine.

A radioimmunoassay as well as an enzyme immunoassay for the quantitation of fmol amounts of the alkaloid colchicine have been developed. The antiserum used for both assays was raised against a conjugate of colchicoside-bovine serum albumin. The crude serum was satisfactory for the performance of the radioimmunoassay. For the enzyme immunoassay, the antibodies had to be isolated and purified by Rivanol treatment with subsequent (NH4)2SO4 precipitation. The measuring range extends from 0.1 to 100 ng colchicine for the radioimmunoassay and from 0.05 to 350 ng for the enzyme immunoassay with detection limits of 125 fmol and 25 fmol, respectively. Both immunoassays cross reacted with colchicoside and 3-demethyl-colchicine up to 80%. The colchicine content in the newly established suspension culture of Colchicum variegatum as well as the influence of various culture media on the colchicine production of this cell culture were investigated with the radioimmunoassay. The enzyme immunoassay was well suited for the quantitation of colchicine in HPLC fractions of Gloriosa and Colchicum seed extracts allowing the rapid, sensitive, and precise determination of the substance under investigation. The preliminary experiments indicate that both colchicine immunoassays can be a useful tool for the analysis of colchicine in tissue and cell culture studies, for analysis of plant extracts as well as for biosynthetic investigations.

Enzyme immunoassay for the quantitative determination of galanthamine.

An enzyme immunoassay for the quantitation of fmol amounts of the therapeutically important Amaryllidaceae alkaloid, galanthamine, was established. The antiserum was raised against a conjugate of galanthamine-2- O-hemisuccinate-bovine serum albumin. The antibodies used were isolated and purified by Rivanol treatment with subsequent (NH (4)) (2)SO (4) precipitation. The measuring range of the assay extends from 2 to lOO pg of galanthamine, and as little as 3.5 fmol may be detected. The antibodies are highly specific for galanthamine, showing no cross reactivity with several Amaryllidaceae alkaloids. This assay allows the rapid, sensitive and precise quantitation of galanthamine in unpurified plant extracts as well as biological fluids. The galanthamine content in a variety of herbarium material as well as the frequency distribution of galanthamine in 1000 LEUCOJUM AESTIVUM plants from various origins in South Bulgaria have been investigated. The preliminary results demonstrate that the galanthamine-specific enzyme immunoassay can be a useful tool in medicinal plant breeding, for screening programs, as well as for taxonomic and pharmacokinetic studies.

Radioimmunoassay for the quantitative determination of galanthamine.

A radioimmunoassay for the quantitation of pmol amounts of the therapeutically important Amaryllidaceae alkaloid, galanthamine, has been developed. The antiserum was raised against a conjugate of galanthamine-2-O-hemisuccinate-bovine serum albumin. The measuring range of the assay extends from 0.5 to 100 ng of galanthamine, and as little as 3.5 pmol may be detected. The antiserum is highly specific for galanthamine, showing practically no cross reactivity with different representatives of the most frequently occurring types of alkaloidal structures in Amaryllidaceae. This assay enables a rapid, sensitive and precise quantitation of galanthamine in unpurified plant extracts. The galanthamine concentration in bulbs of several Leucojum aestivum plants and the distribution of galanthamine in some Amaryllidaceae genera of South African origin have been investigated. Preliminary experiments indicate that the galanthamine-specific radioimmunoassay can be a useful tool in medicinal plant breeding as well as in tissue and cell culture studies.