Two Kaempferol Sophorosides fromCrocus Sativus

Bioactivity and applications of saffron floral bio-residues (tepals): a natural by-product for the food, pharmaceutical, and cosmetic industries

Saffron "Crocus sativus" is a plant of the Iridaceae family. Its therapeutic virtues have been known since antiquity; it is used in traditional medicine and culinary preparations. It is also known for its use in cosmetics because of its beneficial pharmacological activities for human skin. In particular, saffron tepals are the main by-product of saffron processing; they contain several bioactive compounds such as mineral agents, anthocyanins, monoterpenoids, carotenoids, flavonoids, and flavonols (kaempferol). This review aims to describe the different properties of saffron flower tepals, including their botanical characteristics, phytochemical composition, biological activities, and cosmetology and perfumery uses.

Effective Isolation of Picrocrocin and Crocins from Saffron: From HPTLC to Working Standard Obtaining

Saffron is widely cultivated and used as a spice. Recently published data on the chemical composition and pharmacological potential of saffron determine its use in pharmacy and medicine. The proposed high-performance thin-layer chromatography (HPTLC) method allows good separation of 11 analytes. The saffron quality (Iran, Ukraine, Spain, Morocco samples) assessment was based on the European Pharmacopoeia monograph and ISO 3632. The HPTLC method for the safranal, crocin, and picrocrocin quantification was proposed and validated. The crocins content in Ukrainian saffron was from 17.80% to 33.25%. Based on qualitative and quantitative assessment results, the saffron sample from Zaporizhzhia (Ukraine) had the highest compounds content and was chosen to obtain the working standards of picrocrocin and crocins (trans-4GG, trans-2G, trans-3Gg) by preparative chromatography. The compounds were isolated from lyophilized extract of saffron using a Symmetry Prep C18 column (300 × 19 mm × 7 µm), and identified by spectroscopic techniques (HPLC-DAD, UPLC-ESI-MS/MS). The purity of crocins and picrocrocin was more than 97%. A novel method proposed to obtain working standards is simple and reproducible for the routine analysis of saffron quality control.

Comparative analysis of apocarotenoids and phenolic constituents of Crocus sativus stigmas from 11 countries: Ecological impact

The chemical compositions of 15 saffron samples from 11 countries (Morocco, India, Italy, Spain, Germany, Switzerland, Iran, Lithuania, Ukraine, Australia, and Azerbaijan) were evaluated. The samples were analyzed regarding the impact of environmental factors on the composition of apocarotenoids and phenolic constituents. Quantification of saffron metabolites was carried out using high-performance liquid chromatography. It was found that the high content of chlorogenic acid (0.2 mg/g, Ukraine) and ferulic acid (0.28 mg/g, India) was controlled by the duration of solar radiation during plant development. The accumulation of caffeic acid (the higher content 4.88 mg/g, Ukraine) in stigmas depended on the average air temperature. In contrast, the total crocins content according to the correlation analysis depended on the duration of solar radiation, the solar UV index, and the soil type. Rutin was found in all samples (0.83-8.74 mg/g). The highest amount of crocins (average 382.45 mg/g) accumulated in saffron from Italy and Ukraine. Crocins, picrocrocin, safranal, and rutin can further serve as saffron quality markers. All validation parameters were satisfactory and high-performance liquid chromatography methods could be successfully applied for the composition assessment of saffron metabolites. Saffron extracts showed the highest antibacterial activity against Bacillus subtilis, Staphylococcus aureus, and Escherichia coli (MICs 62.5-125 µg/ml).

Nutritional and health beneficial properties of saffron (Crocus sativus L): a comprehensive review

Saffron (Crocus sativus L., family Iridaceae) is used traditionally for medicinal purpose in Chinese, Ayurvedic, Persian and Unani medicines. The bioactive constituents such as apocarotenoids, monoterpenoids, flavonoids, phenolic acids and phytosterols are widely investigated in experimental and clinical studies for a wide range of therapeutic effects, especially on the nervous system. Some of the active constituents of saffron have high bioavailability and bioaccessibility and ability to pass the blood-brain barrier. Multiple preclinical and clinical studies have supported neuroprotective, anxiolytic, antidepressant, learning and memory-enhancing effect of saffron and its bioactive constituents (safranal, crocin, and picrocrocin). Thus, this plant and its active compounds could be a beneficial medicinal food ingredient in the formation of drugs targeting nervous system disorders. This review focuses on phytochemistry, bioaccessibility, bioavailability, and bioactivity of phytochemicals in saffron. Furthermore, the therapeutic effect of saffron against different nervous system disorders has also been discussed in detail.

Bioactivity and Bioavailability of the Major Metabolites of Crocus sativus L. Flower

Crocus sativus L. has been cultivated throughout history to obtain its flowers, whose dried stigmas give rise to the spice known as saffron. Crocetin esters, picrocrocin, and safranal are the main metabolites of this spice, which possess a great bioactivity, although the mechanisms of action and its bioavailability are still to be solved. The rest of the flower is composed by style, tepals, and stamens that have other compounds, such as kaempferol and delphinidin, which have an important antioxidant capacity, and these can be applied in foods, phytopharmaceuticals, and cosmetics. The aim of this work was to provide an updated and critical review of the research on the main compounds of Crocus sativus L. flower, including the adequate analytical methods for their identification and quantification, with a focus on their bioactivity and bioavailability.

Biologically active compounds and pharmacological activities of species of the genus Crocus: A review

The present article is the first comprehensive review on the chemical composition and pharmacological activities of the raw materials of Crocus species. In the present review, data on chemical constituents and pharmacological profile of Crocus sativus stigmas, as well as of other plant parts (perianth, stamens, leaves, corms) of different Crocus spp. are given. This review discusses all the classes of compounds (carotenoids, flavonoids, anthocyanins, terpenoids, phenol carboxylic acids, etc.) detected in raw materials of Crocus plants providing information on the current state of knowledge on phytochemicals of Crocus species. Almost all structural formulas of the compounds identified and isolated from Crocus species are given; all compounds are presented in accordance with the types of the studied raw materials. The latest hypotheses relating to the biosynthesis pathways of the main biologically active compounds of saffron (crocin, picrocrocin, safranal), as well as chemotaxonomy of Crocus genus are briefly summarized. The present review discusses the most thoroughly studied pharmacological activities (namely, antioxidant, antiparasitic, hypolipidemic, antihypertensive, immunomodulatory, antimicrobial, antitumor, cytotoxic, antidepressant) of saffron stigmas extracts, of its individual phytochemicals (safranal, crocin, crocetin), as well as pharmacological activities of raw materials of other Crocus species. This comprehensive review will be informative for scientists searching for new properties of saffron stigmas, as well as for saffron producers, since the present review highlights the prospects for the use of waste products in the production of the expensive spice. In addition, the present review provides information on pharmacological properties and composition of other Crocus species as promising medicinal and food plants. In the present review the emphasis will be put on the chemical constituents of Crocus species and the intraspecies variation in phytochemicals and pharmacological activities.

Ameliorative potential of Alstonia scholaris (Linn.) R. Br. against chronic constriction injury-induced neuropathic pain in rats

BACKGROUND

Alstonia scholaris commonly known as 'Saptaparni' is an Indian traditional medicinal plant used in Ayurveda. It is commonly used to treat various disorders like asthma, bronchitis, diarrhea, dysentery and malaria. In folklore medicine the milky juice of the plant is applied on wounds and ulcers to treat pain, ear ache and also in rheumatic pains.

AIM

The present study was designed to investigate the potential of A. scholaris R. Br. in chronic constriction injury of sciatic nerve (CCI) induced neuropathic pain in rats.

METHODS

Peripheral neuropathy was induced by chronic constriction injury of sciatic nerve. The behavioral parameters like mechanical and thermal hyperalgesia and cold allodynia were assessed on the 14^th day. Tissue parameters like total protein, thiobarbituric acid reactive substances, reduced glutathione, myeloperoxidase, total calcium and TNF-α were assessed to check biochemical changes. Chloroform and methanol extract of A. scholaris leaves (100 and 200 mg/kg) and pregabalin (10 mg/kg, as positive control) were administered orally for 14 consecutive days starting from the day of surgery.

RESULTS

CCI resulted in significant development of mechanical hyperalgesia, heat hyperalgesia and cold allodynia along with alteration in the biochemical changes. Administration of methanol extract at 200 mg/kg significantly attenuated the CCI induced change in nociceptive threshold and biochemical changes which was comparable to that of pregabalin. The high-performance liquid chromatography (HPLC) of the bioactive methanol extract revealed the presence of different types of flavonoids such as gallic acid, catechin, epicatechin, ellagic acid and kaempferol, in which kaempferol was observed to be in higher concentration.

CONCLUSION

Methanol extract (200 mg/kg) of A. scholaris showed the ameliorative effect in CCI induced neuropathic pain which may be due to the presence of kaempferol and attributed to its anti-oxidative and anti-inflammatory properties.

Petals of Crocus sativus L. as a potential source of the antioxidants crocin and kaempferol

Saffron from the province of L'Aquila, in the Abruzzo region of Italy, is highly prized and has been awarded a formal recognition by the European Union with EU Protected Designation of Origin (PDO) status. Despite this, the saffron regions are abandoned by the younger generations because the traditional cultivation of saffron (Crocus sativus L.) is labour intensive and yields only one crop of valuable saffron stamens per year. Petals of the saffron Crocus have had additional uses in traditional medicine and may add value to the crops for local farmers. This is especially important because the plant only flowers between October and November, and farmers will need to make the best use of the flowers harvested in this period. Recently, the petals of C. sativus L., which are considered a waste material in the production of saffron spice, were identified as a potential source of natural antioxidants. The antioxidants crocin and kaempferol were purified by flash column chromatography, and identified by thin layer chromatography (TLC), HPLC-DAD, infrared (IR), and nuclear magnetic resonance ((1)H &(13)C NMR) spectroscopy. The antioxidant activity was determined with the ABTS and DPPH tests. The antioxidant activities are mainly attributed to carotenoid and flavonoid compounds, notably glycosides of crocin and kaempferol. We found in dried petals 0.6% (w/w) and 12.6 (w/w) of crocin and kaempferol, respectively. Petals of C. sativus L. have commercial potential as a source for kaempferol and crocetin glycosides, natural compounds with antioxidant activity that are considered to be the active ingredients in saffron-based herbal medicine.

Kaempferol and inflammation: From chemistry to medicine

Inflammation is an important process of human healing response, wherein the tissues respond to injuries induced by many agents including pathogens. It is characterized by pain, redness and heat in the injured tissues. Chronic inflammation seems to be associated with different types of diseases such as arthritis, allergies, atherosclerosis, and even cancer. In recent years natural product based drugs are considered as the novel therapeutic strategy for prevention and treatment of inflammatory diseases. Among the different types of phyto-constituents present in natural products, flavonoids which occur in many vegetable foods and herbal medicines are considered as the most active constituent, which has the potency to ameliorate inflammation under both in vitro and in vivo conditions. Kaempferol is a natural flavonol present in different plant species, which has been described to possess potent anti-inflammatory properties. Despite the voluminous literature on the anti-inflammatory effects of kaempferol, only very limited review articles has been published on this topic. Hence the present review is aimed to provide a critical overview on the anti-inflammatory effects and the mechanisms of action of kaempferol, based on the current scientific literature. In addition, emphasis is also given on the chemistry, natural sources, bioavailability and toxicity of kaempferol.

Characterization of a glucosyltransferase enzyme involved in the formation of kaempferol and quercetin sophorosides in Crocus sativus

UGT707B1 is a new glucosyltransferase isolated from saffron (Crocus sativus) that localizes to the cytoplasm and the nucleus of stigma and tepal cells. UGT707B1 transcripts were detected in the stigma tissue of all the Crocus species analyzed, but expression analysis of UGT707B1 in tepals revealed its absence in certain species. The analysis of the glucosylated flavonoids present in Crocus tepals reveals the presence of two major flavonoid compounds in saffron: kaempferol-3-O-β-D-glucopyranosyl-(1-2)-β-D-glucopyranoside and quercetin-3-O-β-D-glucopyranosyl-(1-2)-β-D-glucopyranoside, both of which were absent from the tepals of those Crocus species that did not express UGT707B1. Transgenic Arabidopsis (Arabidopsis thaliana) plants constitutively expressing UGT707B1 under the control of the cauliflower mosaic virus 35S promoter have been constructed and their phenotype analyzed. The transgenic lines displayed a number of changes that resembled those described previously in lines where flavonoid levels had been altered. The plants showed hyponastic leaves, a reduced number of trichomes, thicker stems, and flowering delay. Levels of flavonoids measured in extracts of the transgenic plants showed changes in the composition of flavonols when compared with wild-type plants. The major differences were observed in the extracts from stems and flowers, with an increase in 3-sophoroside flavonol glucosides. Furthermore, a new compound not detected in ecotype Columbia wild-type plants was detected in all the tissues and identified as kaempferol-3-O-sophoroside-7-O-rhamnoside. These data reveal the involvement of UGT707B1 in the biosynthesis of flavonol-3-O-sophorosides and how significant changes in flavonoid homeostasis can be caused by the overproduction of a flavonoid-conjugating enzyme.

Cloning and characterization of a glucosyltransferase from Crocus sativus stigmas involved in flavonoid glucosylation

BACKGROUND

Flavonol glucosides constitute the second group of secondary metabolites that accumulate in Crocus sativus stigmas. To date there are no reports of functionally characterized flavonoid glucosyltransferases in C. sativus, despite the importance of these compounds as antioxidant agents. Moreover, their bitter taste makes them excellent candidates for consideration as potential organoleptic agents of saffron spice, the dry stigmas of C. sativus.

RESULTS

Using degenerate primers designed to match the plant secondary product glucosyltransferase (PSPG) box we cloned a full length cDNA encoding CsGT45 from C. sativus stigmas. This protein showed homology with flavonoid glucosyltransferases. In vitro reactions showed that CsGT45 catalyses the transfer of glucose from UDP_glucose to kaempferol and quercetin. Kaempferol is the unique flavonol present in C. sativus stigmas and the levels of its glucosides changed during stigma development, and these changes, are correlated with the expression levels of CsGT45 during these developmental stages.

CONCLUSION

Findings presented here suggest that CsGT45 is an active enzyme that plays a role in the formation of flavonoid glucosides in C. sativus.

Flavonols and an indole alkaloid skeleton bearing identical acylated glycosidic groups from yellow petals of Papaver nudicaule

From yellow petals of Iceland poppy, besides the known flavonoid gossypitrin, seven kaempferol derivatives were isolated. In addition to kaempferol 3-O-beta-sophoroside and kaempferol 3-O-beta-sophoroside-7-O-beta-glucoside, known from other plants, the mono- and dimalonyl conjugates of the latter were identified by MS and NMR spectroscopy. Structure analyses of a set of co-occurring pigments, the nudicaulins, revealed that they have the identical acylated glycoside moieties attached to a pentacyclic indole alkaloid skeleton for which the structure of 19-(4-hydroxyphenyl)-10H-1,10-ethenochromeno[2,3-b]indole-6,8,18-triol was deduced from MS and NMR as well as chemical and chiroptical methods.