Plant growth-promoting rhizobacteria (PGPR) are the rhizosphere bacteria that can enhance plant growth by a wide variety of mechanisms like phosphate solubilization, siderophore production, biological nitrogen fixation, rhizosphere engineering, production of 1-Aminocyclopropane-1-carboxylate deaminase (ACC), quorum sensing (QS) signal interference and inhibition of biofilm formation, phytohormone production, exhibiting antifungal activity, production of volatile organic compounds (VOCs), induction of systemic resistance, promoting beneficial plant-microbe symbioses, interference with pathogen toxin production etc. The potentiality of PGPR in agriculture is steadily increased as it offers an attractive way to replace the use of chemical fertilizers, pesticides and other supplements. Growth promoting substances are likely to be produced in large quantities by these rhizosphere microorganisms that influence indirectly on the overall morphology of the plants. Recent progress in our understanding on the diversity of PGPR in the rhizosphere along with their colonization ability and mechanism of action should facilitate their application as a reliable component in the management of sustainable agricultural system. The progress to date in using the rhizosphere bacteria in a variety of applications related to agricultural improvement along with their mechanism of action with special reference to plant growth-promoting traits are summarized and discussed in this review.

Plant growth-promoting rhizobacteria (PGPR): emergence in agriculture

Herbs, spices and their active components as natural antimicrobials in foods Effect of natural antioxidants in herbs and spices on shelf life of foods Ajowan Aniseed Asafoetida Allspice Capers and caperberries Caraway Celery Chervil Fennel and fennel seed Galangal Kaffir lime leaf Lavender Lemongrass Lovage Nigella Oregano Poppy Sesame Star anise Tarragon Tamarind Other significant herbs and spices.

Handbook of Herbs and Spices

Background
Crocus sativus L. (saffron) is used in folk medicine, for example as an antiedematogenic agent. We aimed to evaluate the antinociceptive and anti-inflammatory activity of saffron extracts in mice.

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Antinociceptive and anti-inflammatory effects of Crocus sativus L. stigma and petal extracts in mice

Plant carotenoids are a family of pigments that participate in light harvesting and are essential for photoprotection against excess light. Furthermore, they act as precursors for the production of apocarotenoid hormones such as abscisic acid and strigolactones. In this review, we summarize the current knowledge on the genes and enzymes of the carotenoid biosynthetic pathway (which is now almost completely elucidated) and on the regulation of carotenoid biosynthesis at both transcriptional and post-transcriptional levels. We also discuss the relevance of Arabidopsis as a model system for the study of carotenogenesis and how metabolic engineering approaches in this plant have taught important lessons for carotenoid biotechnology.

https://bioone.org/journals/the-arabidopsis-book/volume-2012/issue-10/tab.0158/Carotenoid-Biosynthesis-in-Arabidopsis-A-Colorful-Pathway/10.1199/tab.0158.pdf

Carotenoid biosynthesis in Arabidopsis: a colorful pathway.

Since cancer is the most common cause of death in the world population, the possibility that readily available natural substances from plants, vegetables, herbs, and spices may be beneficial in the prevention of cancer warrants closer examination. Saffron in filaments is the dried, dark red stigmata of Crocus sativus L. flowers and it is used as a spice, food colorant, and a drug in medicine. A growing body of research has demonstrated that saffron extract itself and its main constituents, the carotenoids, possess chemopreventive properties against cancer. This review discusses recent literature data and our results on the cancer chemopreventive activities of saffron and its main ingredients.

Cancer chemopreventive and tumoricidal properties of saffron (Crocus sativus L.).

Crocin, safranal and picrocrocin from saffron (Crocus sativus L.) inhibit the growth of human cancer cells in vitro

Saffron is made with the dried stigmas of Crocus sativus L., an Iridaceae that has been traditionally cultivated in different countries of Asia and the Mediterranean region. Saffron production at a worldwide scale is facing challenging tasks such as the need of new farming techniques, genetic improvement, propagation of high quality plant material, conservation of genetic resources, new chemical technologies to assess quality and prevent adulteration of saffron, and to develop a wide range of saffron uses, particularly those related to human health. The application of modern technologies from the fields of molecular biology, cell biology, biochemistry, genetics and genomics could help to achieve these objectives. This article reviews some of the latest advances carried out on the biology, biotechnology and biomedicine of this ancient crop.

Biology, biotechnology and biomedicine of saffron

We used an experimental model in the rat to examine the effects of long-term treatment with crocin, a glycosylated carotenoid from the stigmas of the saffron crocus, on colon cancer. BD-IX rats were divided into four groups: Groups G1 and G2, designated "cancer groups," were used to study the effects of crocin on the progression of colon cancer, and Groups G3 and G4, designated "toxicity groups," were used to study the effects of the treatment on metabolic processes and the parenchyma. DHD/K12-PROb cells were injected subcutaneously into the chest of Group G1 and G2 animals. From 1 to 13 weeks after inoculation, animals in Groups G2 and G4 received a weekly injection of crocin (400 mg/kg body wt s.c.). Animals in Groups G1 and G3 received no treatment. In addition, lines of animal and human colon adenocarcinoma cells (DHD/K12-PROb and HT-29) were used to perform assays in vitro to examine the cytotoxicity of crocin. Life span was extended and tumor growth was slower in crocin-treated female rats, but no significant antitumor effect was found in male rats. Acute tubular necrosis was found in all kidney samples from crocin-treated animals, but slight signs of nephrotoxicity were found by biochemical analysis of the serum. In assays in vitro, crocin had a potent cytotoxic effect on human and animal adenocarcinoma cells (HT-29 and DHD/K12-PROb cells, 50% lethal dose = 0.4 and 1.0 mM, respectively). Treated cells exhibited a remarkable loss of cytoplasm and wide cytoplasmic vacuole-like areas. In conclusion, long-term treatment with crocin enhances survival selectively in female rats with colon cancer without major toxic effects. The effects of crocin might be related to its strong cytotoxic effect on cultured tumor cells.

Effects of Long-Term Treatment of Colon Adenocarcinoma With Crocin, a Carotenoid From Saffron (Crocus sativus L.): An Experimental Study in the Rat

Crocus sativus is a triploid sterile plant characterized by its long red stigmas, which produce and store significant quantities of the apocarotenoids crocetin and crocin, formed from the oxidative cleavage of zeaxanthin. Here, we investigate the accumulation and the molecular mechanisms that regulate the synthesis of these apocarotenoids during stigma development in C. sativus. We cloned the cDNAs for phytoene synthase, lycopene-β-cyclase, and β-ring hydroxylase from C. sativus. With the transition of yellow undeveloped to red fully developed stigmas, an accumulation of zeaxanthin was observed, accompanying the expression of CsPSY, phytoene desaturase, and CsLYCb, and the massive accumulation of CsBCH and CsZCD transcripts. We analyzed the expression of these two transcripts in relation to zeaxanthin and apocarotenoid accumulation in other Crocus species. We observed that only the relative levels of zeaxanthin in the stigma of each cultivar were correlated with the level of CsBCH transcripts. By contrast, the expression levels of CsZCD were not mirrored by changes in the apocarotenoid content, suggesting that the reaction catalyzed by the CsBCH enzyme could be the limiting step in the formation of saffron apocarotenoids in the stigma tissue. Phylogenetic analysis of the CsBCH intron sequences allowed us to determine the relationships among 19 Crocus species and to identify the closely related diploids of C. sativus. In addition, we examined the levels of the carotenoid and apocarotenoid biosynthetic genes in the triploid C. sativus and its closer relatives to determine whether the quantities of these specific mRNAs were additive or not in C. sativus. Transcript levels in saffron were clearly higher and nonadditive, suggesting that, in the triploid gene, regulatory interactions that produce novel effects on carotenoid biosynthesis genes are involved.

Implications of Carotenoid Biosynthetic Genes in Apocarotenoid Formation during the Stigma Development of Crocus sativus and Its Closer Relatives

In the diagnosis of human brucellosis, PCR could be a more sensitive technique than blood cultures and more specific than conventional serological tests. We compared three different PCR methods for the detection of Brucella spp. and we studied whether human genomic DNA affect the sensitivity of three primer pairs for the detection of Brucella DNA in a peripheral-blood PCR assay. These three pairs of primers amplified three different fragments included in: (i) a gene encoding a 31-kDa Brucella abortus antigen (primers B4/B5), (ii) a sequence 16S rRNA of B. abortus (primers F4/R2), and (iii) a gene encoding an outer membrane protein (omp-2) (primers JPF/JPR). The three primers assayed showed a difference in sensitivity for detecting purified Brucella DNA, ranging between 8 fg and 20 pg. However, the sensitivity of the primers F4/R2 and B4/B5 was affected by the presence of human DNA while the primers JPF/JPR were not. Therefore, although the sensitivity of PCR using primers F4/R2 is affected by human DNA, they are still the most sensitive and they could provide a useful tool for the diagnosis of human brucellosis.

J. A. Fernández

Papers

Crocin, safranal and picrocrocin from saffron (Crocus sativus L.) inhibit the growth of human cancer cells in vitro

Biology, biotechnology and biomedicine of saffron

Effects of Long-Term Treatment of Colon Adenocarcinoma With Crocin, a Carotenoid From Saffron (Crocus sativus L.): An Experimental Study in the Rat

Implications of Carotenoid Biosynthetic Genes in Apocarotenoid Formation during the Stigma Development of Crocus sativus and Its Closer Relatives

Comparison of three different PCR methods for detection of Brucella spp. in human blood samples