Symplastic continuity between companion cells and the translocation stream: long-distance transport is controlled by retention and retrieval mechanisms in the phloem. (1/17)

Substantial symplastic continuity appears to exist between companion cells (CCs) and sieve elements of the phloem, which suggests that small solutes within the CC are subject to indiscriminate long-distance transport via the translocation stream. To test this hypothesis, the distributions of exotic and endogenous solutes synthesized in the CCs of minor veins were studied. Octopine, a charged molecule derived from arginine and pyruvate, was efficiently transported through the phloem but was also transferred in substantial amounts to the apoplast, and presumably other non-phloem compartments. The disaccharide galactinol also accumulated in non-phloem compartments, but long-distance transport was limited. Conversely, sucrose, raffinose, and especially stachyose demonstrated reduced accumulation and efficient transport out of the leaf. We conclude that small metabolites in the cytosol of CCs do enter the translocation stream indiscriminately but are also subject to distributive forces, such as nonselective and carrier-mediated membrane transport and symplastic dispersal, that may effectively clear a compound from the phloem or retain it for long-distance transport. A model is proposed in which the transport of oligosaccharides is an adaptive strategy to improve photoassimilate retention, and consequently translocation efficiency, in the phloem.  (+info)

Molecular cloning and functional expression of geranylgeranyl pyrophosphate synthase from Coleus forskohlii Briq. (2/17)

BACKGROUND: Isopentenyl diphosphate (IPP), a common biosynthetic precursor to the labdane diterpene forskolin, has been biosynthesised via a non-mevalonate pathway. Geranylgeranyl diphosphate (GGPP) synthase is an important branch point enzyme in terpenoid biosynthesis. Therefore, GGPP synthase is thought to be a key enzyme in biosynthesis of forskolin. Herein we report the first confirmation of the GGPP synthase gene in Coleus forskohlii Briq. RESULTS: The open reading frame for full-length GGPP synthase encodes a protein of 359 amino acids, in which 1,077 nucleotides long with calculated molecular mass of 39.3 kDa. Alignments of C. forskohlii GGPP synthase amino acid sequences revealed high homologies with other plant GGPP synthases. Several highly conserved regions, including two aspartate-rich motifs were identified. Transient expression of the N-terminal region of C. forskohlii GGPP synthase-GFP fusion protein in tobacco cells demonstrated subcellular localization in the chloroplast. Carotenoid production was observed in Escherichia coli harboring pACCAR25DeltacrtE from Erwinia uredovora and plasmid carrying C. forskohlii GGPP synthase. These results suggested that cDNA encoded functional GGPP synthase. Furthermore, C. forskohlii GGPP synthase expression was strong in leaves, decreased in stems and very little expression was observed in roots. CONCLUSION: This investigation proposed that forskolin was synthesised via a non-mevalonate pathway. GGPP synthase is thought to be involved in the biosynthesis of forskolin, which is primarily synthesised in the leaves and subsequently accumulates in the stems and roots.  (+info)

Effects of Coleus forskohlii on fat storage in ovariectomized rats. (3/17)

The antiobesity effects of Coleus forskohlii were investigated in ovariectomized (ovx) rats. Eight-week-old female Wistar rats were assigned to four groups: a sham-operated group fed the control diet (MF, sham-m) ; an ovx-m group fed the control diet; a sham-operated group fed the control diet containing 50 g/kg of Coleus forskohlii extract (sham-c) ; and an ovx-c group fed the control diet containing 50 g/kg of Coleus forskohlii extract. The body weight, adipose tissues, and cell diameter were investigated in ovx rats after Coleus forskohlii extract treatment. Administration of Coleus forskohlii extracts reduced body weight, food intake, and fat accumulation in ovx rats. Our results suggest that Coleus forskohlii may be useful in the treatment of obesity.  (+info)

Water-soluble extract of Coleus barbatus modulates weight gain, energy utilization and lipid metabolism in secondary biliary cirrhosis: an experimental study in young rats. (4/17)

PURPOSE: To test if a water extract of Coleus barbatus (WEB) has any effect on weight gain, food energy utilization and lipid metabolism in young rats with obstructive cholestasis. METHODS: Forty 21 day old (P21) Wistar rats, in groups of 10, were submitted to one of the following treatments: a sham operation with daily water or WEB administration, double ligature and resection of the bile duct with daily water or WEB administration. At P49 they were submitted for euthanasia when the following were determined: ingested feed (IF), energy utilization (EU) and weight gain (WG) from P29 to P49, together with total serum cholesterol (TC) and triacylglycerol (TG) concentrations, liver wet weight (LWW) and fat content (LFC). Two Way ANOVA and the S.N.K. test for paired comparisons were employed to study the effects of cholestasis and those of WEB and their interactions (p < or = 0.05). RESULTS: Cholestasis, independently of WEB, and WEB, independently of cholestasis both reduced IF, EU, and WG but there was no significant interaction between the two factors. Cholestasis, independently of WEB, increased LWW, LFC, the TC and TG The WEB, independently of cholestasis, reduced these values, and there was a significant interaction between the two factors; such that these effects were more accentuated in animals with cholestasis. CONCLUSION: The WEB reduced IF, WG, and EU, both in the presence and absence of cholestasis in the same proportion. It also partially inhibited the increase in LWW, LFC, TC and TG caused by cholestasis.  (+info)

Lactagogue effects of Torbangun, a Bataknese traditional cuisine. (5/17)

Coleus amboinicus Lour (CA) has been used as a breast milk stimulant (a lactagogue) by Bataknese people in Indonesia for hundreds of years. However, the traditional use of CA is not well documented, and scientific evidence is limited to establish CA as a lactagogue. This investigation was conducted to elucidate the effect of traditional use of CA during the first month of lactation on quantity and quality of the breast milk. The results collected from the study show that CA supplementation increased breast milk production without compromising the nutritional quality of the breast milk. Lactating women receiving CA supplementation had a 65% increase in milk volume during the last two weeks of supplementation (from Day 14 to Day 28). This increase was greater than that of lactating women receiving Molocco+B12 tablets (10%) or Fenugreek seeds (20%). The residual effects of CA supplementation were seen even after the supplementation had ended for one month. Results of the present study confirmed the belief and the practice amongst the Bataknese people that CA can be used as a lactagogue in humans, and the use of CA might be suitable for lactating women in general.  (+info)

Antioxidant, anticlastogenic and radioprotective effect of Coleus aromaticus on Chinese hamster fibroblast cells (V79) exposed to gamma radiation. (6/17)

Coleus aromaticus (Benth, Family: Laminaceae), Indian Oregano native to India and Mediterranean, is well known for its medicinal properties. A preliminary study was undertaken to elucidate in vitro free radical scavenging potential and inhibition of lipid peroxidation by C.aromaticus hydroalcoholic extract (CAE). Anti-clastogenic and radioprotective potential of CAE were studied using micronucleus assay after irradiating Chinese hamster fibroblast (V79) cells. CAE at 10, 20, 40, 60, 80, 100 and 120 mug/ml resulted in a dose-dependent increase in radical scavenging ability against various free radicals viz., 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), superoxide anion (O(2)(*-)), hydroxyl (OH(*)) and nitric oxide (NO(*)) generated in vitro. A maximum scavenging potential was noticed at 100 mug/ml and a saturation point was reached thereafter with the increasing doses of CAE. The free radical scavenging potential of the extract was in the order of DPPH > ABTS > Superoxide > Hydroxyl > Nitric oxide. CAE also exhibited a moderate inhibition of lipid peroxidation in vitro, with a maximum inhibition at 60 mug/ml (33%), attaining saturation at higher doses. The extract also rendered protection against radiation induced DNA damage, as evidenced by the significant (P < 0.05) decrease in the percentage of radiation-induced micronucleated cells (MN) and frequency of micronuclei (total). A maximum anticlastogneic effect/ radioprotection was noticed at a very low concentration i.e., 5 mug/ml of CAE, treated 1 h prior to 2 Gy of gamma radiation. A significant (P < 0.0001) anticlastogenic/radioprotective effect was also observed when the cells were treated with an optimum dose of CAE (5 mug/ml) 1 h prior to 0.5, 1, 2 and 4 Gy of gamma radiation compared with the respective radiation control groups. Overall, our results established an efficient antioxidant, anticlastogenic and radioprotective potential of CAE, which may be of great pharmacological importance.  (+info)

Potential application of urea-derived herbicides as cytokinins in plant tissue culture. (7/17)

Various urea-derived herbicides and different cytokinin analogues were used to determine their effects on callusing response and shoot regenerating capacity of alfalfa (Medicago sativa L.) and Coleus (Coleus forskohlii Briq.). The herbicides monuron and diuron evoked profuse callusing response from Coleus leaf segments and alfalfa petiole explants on Murashige and Skoog medium. Shoot regeneration by monuron (2.0 mg/l) showed a maximum of 3 multiple shoots both in alfalfa and Coleus with a frequency of 92% and 75%, respectively. Whereas diuron (0.5 mg/l) showed a high frequency of shoot regeneration (89%)with a mean number of 5 shoots in alfalfa, in C.forskohlii, the frequency of regeneration was 90%with a mean number of 6 shoots. Diuron with two chloride groups in the phenyl ring showed significantly higher cytokinin-like activity than single chloride substitution monuron. This study demonstrates the potential use of monuron and diuron as cytokinins in plant tissue culture.  (+info)

Two minor diterpene glycosides and an eudesman sesquiterpene from Coleus forskohlii. (8/17)

Two new labdane diterpene glycosides, forskoditerpenosides A, B (1, 2) and a new eudesmane sesquiterpene, 4beta,7beta,11-enantioeudesmantriol (3), were isolated from the ethanol extract of the whole plant of Coleus forskohlii. Their structures and stereochemistry were elucidated by extensive spectroscopic analysis and chemical methods. The structure of compound 3 was confirmed by X-ray diffraction. This is the first report about the occurrence of glycosides derived from the kind of labdane diterpene, 8,13-epoxy-labd-14-en-11-one, in the nature. Compounds 1 and 2 showed relaxative effects on isolated guinea pig tracheal spirals in vitro.  (+info)

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