Comparative study on morpho-anatomy of leaf, stem and root of Boerhaavia diffusa L. (Nyctaginaceae) and its adulterant plants

ABSTRACT Punarnava (Boerhaavia diffusa L.- Nyctaginaceae) is a promising drug to rejuvenate new cells in the body. It is well known in Ayurvedic medicine and locally called Tambadivasu. Superficially it is similar to other species of Boerhaavia and species of Trianthema and Sesuvium. Due to the minute morphological differences, the above plants are erroneously used in medicine as Punarnava, and at times on purpose as an adulterant. Therefore, it is necessary to highlight the anatomical features of Punarnava for proper identification of the medicinal plant species for local people and for scientific research. Due to the ambiguity in local names and similar apparent appearance, market samples of Punarnava are often adulterated with various species of Trianthema and Sesuvium. These adulterated samples contain neither the Punarnavine alkaloid, nor does it possess anisocytic stomata but possess paracytic stomata. Comparative study of stem anatomy showed two main characteristic differences. First, plenty of starch grains can be seen in both the ground parenchymatous tissues present in between successive cambia and xylem parenchyma of Punarnava which is not observed in species of Trianthema, and second, the phloem around the xylem of Punarnava root has semi-circular or eccentric patches, while that of Trianthema only has narrow strips. This study is focused on comparative SEM study of leaf morphologies and anatomy of leaf, stem, and root of Boerhaavia diffusa L., Trianthema portulacastrum L. and Sesuvium portulacastrum L.

Screening of Chonemorpha fragrans Bioactive Extracts for Cytotoxicity Potential and Inhibition Studies of Key Enzymes Involved in Replication.

BACKGROUND: Chonemorpha fragrans (Moon) Alston, a liana belonging to family Apocynaceae, is used in traditional medicinal systems for the treatment of various ailments. It is an unexplored medicinal plant with respect to its anticancer potential. OBJECTIVE: Cytotoxicity of sequential as well as crude extracts of in vivo plant parts (leaves, bark, and roots), in vitro cultures, and callus were compared. MATERIALS AND METHODS: 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell proliferation assay was used to compare the extracts of various in vivo plant parts (leaves, bark, and roots) along with in vitro culture systems (in vitro plantlets, callus). Furthermore, the extracts were used to evaluate inhibition of key enzymes involved in replication, i.e. topoisomerase (Topo) I and II, DNA polymerase, to check the probable mechanism of action for this cytotoxicity. RESULTS: MTT assay showed that the chloroform extract of callus has potent anticancer potential. The plant has a promising anticancer activity against human colon epithelium, lung carcinoma, and epidermoidal carcinoma cell lines. It was found to possess Topo as well as DNA polymerase inhibitory activity. CONCLUSION: The results have pointed toward pharmaceutical importance of this plant. This study is the first report of exploring the antiproliferative potential as well as inhibition studies of key enzymes involved in replication, which was useful to point out probable mechanism of action for extracts of C. fragrans. SUMMARY: It's a first report of cytotoxicity studies and inhibition of enzyme involved in the replication process by Chonemorpha fragrans plant extracts. The results reveal the pharmaceutical importance of this plant. From various assays performed here, a potent anticancer potential of chloroform extract of callus was revealed showing Topo I (E. coli and human) inhibitory activity, DNA pol inhibitory activity. Considering the importance of these activities, plant further needs to be explored in detail for in vivo cancer studies as well as for its metabolite content. Abbreviations used: CPT: Camptothecin, EDTA: Ethylenediaminetetraacetic acid, MTT: 3-4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide, Pol: Polymerase, Topo - Topoisomerase.

Effect of polyamines on shoot multiplication and furanocoumarin production in Ruta graveolens cultures.

The influence of the polyamines putrescine (Put), spermine (Spr) and spermidine (Spd) on growth and furanocoumarin production was investigated by exogenous addition, at different concentrations, to shoot cultures of Ruta graveolens at different phases of growth. Preliminary studies indicated that addition of Put (20 microM) and Spr (80 microM) had a promotive effect on shoot multiplication rate and number of multiple shoots formed. Spd was toxic, even at lower concentrations. The growth-phase of the culture at the time of exogenous addition of polyamines was found to be an important factor. Put was most effective when added at the lag phase, while Spr was most effective when added in the log phase. Time course studies of growth and furanocoumarin content were carried out for each polyamine and phase of addition. It was seen that maximum production of furanocoumarins (256.8 mg/10 g DW) occurred in the second week when Put was added in the lag phase and 260.5 mg/10 g DW in the fourth week when Spr was added in the log phase. Put addition resulted in a 3.10 fold increase in psoralen, 6.12 in xanthotoxin and 1.46 fold in bergapten production. Spr addition resulted in a 1.31 fold increase in psoralen, 4.11 fold in xanthotoxin and 1.49 fold in bergapten production. Results indicate that alteration of growth and furanocoumarin production kinetics is a combined outcome of choice of polyamine and the phase of culture at the time of exogenous addition. Polyamine addition enabled significant enhancement in production of pharmaceutically important bergapten and xanthotoxin in shoot cultures of Ruta graveolens, which could be explored for commercial production.

Bioprocess optimization of furanocoumarin elicitation by medium renewal and re-elicitation: a perfusion-based approach.

Effect of various abiotic (methyl jasmonate, salicylic acid) and biotic (yeast extract, Aspergillus niger) elicitors on furanocoumarin production and in situ product removal was studied using shoot cultures of Ruta graveolens L. Elicitation by yeast extract (1% w/v) on day 15 was most effective. It led to 7.8-fold higher furanocoumarin production that was attained 24 h after elicitation and 43% of the product was released into the medium. Changes in the relative concentration of furanocoumarins produced depend on the elicitor used. Molar ratio of bergapten increased to 93% in response to yeast extract. With the perspective of developing a commercially feasible process, an approach for preserving viability of biomass and its reuse needs to be developed. For this, medium renewal strategy was investigated. Removal of the spent medium 48 h after elicitation allowed in situ product removal and proved effective in revival of cultures, allowing reuse of biomass. A week after medium renewal, the revived biomass was re-elicited and a second furanocoumarin production peak was obtained. A perfusion-based bioprocess optimization approach, employing elicitation coupled with medium renewal with subsequent re-elicitation, as a new strategy for improved furanocoumarin production, has been suggested.

Impact of nutrient components on production of the phytoestrogens daidzein and genistein by hairy roots of Psoralea corylifolia.

Transformed hairy roots of Psoralea corylifolia were established by infection with Agrobacterium rhizogenes LBA 9402. The aim of this work was to elucidate the effects of media constituents on production of the phytoestrogenic isoflavones daidzein and genistein. A. rhizogenes strain LBA 9402 harboring Ri plasmid was used to transform stem segments of in vitro seedlings. The resultant hairy roots were confirmed by polymerase chain reaction (PCR) and exhibited Ri T-DNA. Transformed hairy root clones were cultured in Murashige and Skoog's (MS) medium altered with different concentrations of NH(4) (+) and NO(3) (-) and their growth and production of isoflavones were assessed. Biomass and productivity increased when MS medium was supplemented with NH(4) (+) and NO(3) (-) at a ratio of 20:10. Increased yield of daidzein was obtained when sucrose level in the culture medium increased, whereas decreased level of sucrose favored genistein production. The hairy roots produced the highest levels of daidzein (2.06% dry wt.) and genistein (0.37% dry wt.) in the presence of low concentrations of PO(4) (3-). Hairy roots secreted trace amounts of daidzein and genistein into the culture medium. The present results demonstrated that the productivity of daidzein was 2.2-fold more than that of untransformed roots.

Secondary metabolites as DNA topoisomerase inhibitors: A new era towards designing of anticancer drugs.

A large number of secondary metabolites like alkaloids, terpenoids, polyphenols and quinones are produced by the plants. These metabolites can be utilized as natural medicines for the reason that they inhibit the activity of DNA topoisomerase which are the clinical targets for anticancer drugs. DNA topoisomerases are the cellular enzymes that change the topological state of DNA through the breaking and rejoining of DNA strands. Synthetic drugs as inhibitors of topoisomerases have been developed and used in the clinical trials but severe side effects are a serious problem for them therefore, there is a need for the development of novel plant-derived natural drugs and their analogs which may serve as appropriate inhibitors with respect to drug designing. The theme for this review is how secondary metabolites or natural products inactivate the action of DNA topoisomerases and open new avenues towards isolation and characterization of compounds for the development of novel drugs with anticancer potential.

Furanocoumarins: novel topoisomerase I inhibitors from Ruta graveolens L.

Topoisomerase I inhibitors from Ruta graveolens are reported for the first time. Potent topoisomerase I inhibitory activity from in vitro culture extracts R. graveolens were observed. Stabilization of DNA-topoisomerase covalent complex was observed in all the tested extracts. The mechanism of topoisomerase inhibition was determined by preincubation studies. The irreversible topoisomerase I mediated relaxation of plasmid in enzyme-substrate preincubation study, indicated that the observed inhibitory activity of extract constituents was not mediated through conformational changes in the DNA. Furthermore, the affinity of inhibitors with the enzyme was tested by enzyme-extract preincubation study. Increase in inhibition of topoisomerase activity and promotion of DNA-enzyme complex was observed after enzyme-extract preincubation. The activity could be assigned to furanocoumarins-psoralen, bergapten and xanthotoxin, identifying them as novel, potent topoisomerase I inhibitors.

Studied enhancement strategies for phytoestrogens production in shake flasks by suspension culture of Psoralea corylifolia.

This study proposed secondary metabolites incremental yield due to manipulation of nutrient components into the culture medium. To validate this, the effects of nutrients such as carbon, phosphate and nitrogen on growth and production of phytoestrogens daidzein and genistein by suspension cultures of Psoralea corylifolia was investigated for the first time. The maximum production of daidzein and genistein was achieved when sucrose and maltose used as a sole source of carbon. Suspension cell cultures enriched with sucrose (3%) stimulated accumulation of isoflavones daidzein (1.76% dry wt) and genistein (0.25% dry wt) compared to glucose, fructose and maltose. Sucrose feeding strategy significantly stimulated biomass growth and isoflavones (2.79% dry wt of daidzein and 0.32% dry wt of genistein) production rate. Reduced concentrations of phosphate (0.625 mM) promoted daidzein (1.89% dry wt) and genistein (0.26% dry wt) production by suspension cell cultures, whereas high amount (5mM) in medium was inhibited isoflavones production. It was observed that medium fortified with NH(4)(+) and NO(3)(-) alone inhibited production of isoflavones. The maximum production obtained of daidzein (2.20% dry wt) and genistein (0.29% dry wt) when medium comprised with NH(4)(+)/NO(3)(-) at ratio 20:40 mM as a nitrogen source. Similar nutrient components ratio when altered NH(4)(+)/NO(3)(-); 40:20mM) resulted in approximately 3-fold decrease in production. HPLC analysis revealed that suspension cells cultures leached out trace amount of daidzein and genistein into the culture medium.

Novel technique for scaling up of micropropagated Ruta graveolens shoots using liquid culture systems: a step towards commercialization.

Wide applications of Ruta graveolens L. in pharmaceutical industry has led to increased interest in large-scale plant production, with emphasis on use of in vitro cultures. Earlier reports describe use of in vitro germinated seedlings for raising shoot cultures and not regeneration. There is only a single regeneration protocol of R. graveolens; however, it employs conventional labour intensive techniques deterring automation. The aim of present investigation was to establish a cost effective protocol for large-scale plant production. We report for the first time a one-step protocol with improved regeneration efficiency for multiple shoots induction employing liquid culture systems. Effect of polyamines (putrescine and spermine) on growth and furanocoumarin was studied. Addition of spermine enhanced the number of multiple shoots formed (2.5-fold) and reduced the time taken by half. Spermine addition resulted in 1.47-fold in furanocoumarin production. The selected shoot line, RS2 was successfully scaled up to 5L in culture vessels, with 1.53-fold increase in biomass without affecting the productivity of these cultures. This proves to be a commercially feasible alternative to bioreactors for large-scale biomass and furanocoumarin production.