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.

In Vitro Assessment of Myorelaxant and Antispasmodic Effects of Stigmas, Tepals, and Leaves Hydroethanolic Extracts of Crocus sativus

The valorization of Crocus sativus focuses mainly on the plant’s stigma because it is one of the most expensive and valuable spices in the world and has great value in the food, cosmetics, and pharmacological industries. Due to this high stigma value, the other parts of the plant are considered as by-products; our study aimed to evaluate the myorelaxant and antispasmodic activities of the byproducts (tepals and leaves) to compare them with the stigma of the plant. To investigate the myorelaxant and antispasmodic activities of the Crocus sativus on isolated rabbit and rat jejunum, we used an in vitro technic with an organ bath and an isotonic transducer. Our results showed that the STG (hydroethanolic extract of stigmas) and LV (hydroethanolic extract of leaves) had a moderate myorelaxant effect with IC50 = 6.61 ± 1.5 and 5.08 ± 0.45 mg/ml, respectively. TPL (hydroethanolic extract of tepals) had a significant ( $p˂0.001$ ) inhibitory effect on the amplitude of the rabbit jejunum basic contractions with an IC50 = 1.36 ± 0.15 mg/ml. TPL also caused a significant ( $p˂0.001$ ) antispasmodic activity depending on the dose of the contraction induced by CCh (10−6 M) and KCl (25 mM). The antispasmodic effect of the TPL is slightly altered in the presence of nifedipine by a percentage of 26.8%. This difference is statistically significant ( $p˂0.01$ ). Therefore, the extract could induce the inhibitory effect on L-type voltage-dependent Ca2+ channels, but not on the guanylate cyclase and nitric oxide pathways. That confirmed that the TPL has a comparable effect to the verapamil. The HPLC-DAD analysis of various parts of C. sativus shows that the three extracts contain the kaempferol flavanol compound, the STG also was revealed to be rich in carotenoids crocin, and these isomers are trans and cis-crocin, safranal, and picrocrocin. In contrast, the TPL revealed the presence of isorhamnetin and quercetin, but the LV was rich in hesperidin and mangiferin. In conclusion, this study supports the traditional use of this plant to treat digestive problems and will allow us to explore future possibilities for treating bowel spasms using natural molecules derived from saffron.

Crocus sativus L. Stigmas, Tepals, and Leaves Ameliorate Gentamicin-Induced Renal Toxicity: A Biochemical and Histopathological Study

The most costly spice in the world, Crocus sativus L. (C. sativus), has been used for more than 3,000 years. It has various beneficial applications in a range of fields, including aromas, colorants, and medications, but its usefulness as a food flavoring and coloring ingredient is the highest. Large quantities of by-products from the processing of saffron are typically thrown as unwanted bio-residues. This study's goal was to assess and compare the nephroprotective effects of hydroethanolic extracts of C. sativus stigmas, tepals, and leaves on gentamicin (GM)-induced nephrotoxicity in rats. For that, we used a biochemical and histological investigation to propose new pharmaceutical valorizations. Based on the biochemical and histological analyses, it is concluded that all the studied parts of C sativus showed a renoprotective effect. Markedly, tepals revealed the most significant reduction of relative liver weight (p < 0.05), water intake (p < 0.05), plasma creatinine (p < 0.01), plasma urea (p < 0.01), plasma uric acid (p < 0.05), urinary protein (p < 0.01) and albumin (p < 0.001), and renal malondialdehyde (MDA) (p < 0.001). In addition, C. sativus tepals caused a significant increase in body weight (p < 0.05), urinary creatinine (p < 0.01), creatinine clearance (p < 0.05), and urinary urea (p < 0.05) compared with the gentamicin untreated (GM) group. This is confirmed by the histopathological study which shows that treatment with stigmas, tepals, and leaves preserved kidney morphology at the glomerular and tubular cell level. The studied extracts exhibit good recovery potential for nephrotoxicity induced by gentamicin. In order to create potent dietary supplements or phytomedicines, it would also be very interesting to confirm these actions through clinical research.

Antioxidant Activity, Metal Chelating Ability and DNA Protective Effect of the Hydroethanolic Extracts of Crocus sativus Stigmas, Tepals and Leaves

The present study investigated the antioxidant activity, metal chelating ability and genoprotective effect of the hydroethanolic extracts of Crocus sativus stigmas (STG), tepals (TPL) and leaves (LV). We evaluated the antioxidant and metal (Fe2+ and Cu2+) chelating activities of the stigmas, tepals and leaves of C. sativus. Similarly, we examined the genotoxic and DNA protective effect of these parts on rat leukocytes by comet assay. The results showed that TPL contains the best polyphenol content (64.66 µg GA eq/mg extract). The highest radical scavenging activity is shown by the TPL (DPPH radical scavenging activity: IC50 = 80.73 µg/mL). The same extracts gave a better ferric reducing power at a dose of 50 µg/mL, and better protective activity against β-carotene degradation (39.31% of oxidized β-carotene at a 100 µg/mL dose). In addition, they showed a good chelating ability of Fe2+ (48.7% at a 500 µg/mL dose) and Cu2+ (85.02% at a dose of 500 µg/mL). Thus, the antioxidant activity and metal chelating ability in the C. sativus plant is important, and it varies according to the part and dose used. In addition, pretreatment with STG, TPL and LV significantly (p < 0.001) protected rat leukocytes against the elevation of percent DNA in the tail, tail length and tail moment in streptozotocin- and alloxan-induced DNA damage. These results suggest that C. sativus by-products contain natural antioxidant, metal chelating and DNA protective compounds, which are capable of reducing the risk of cancer and other diseases associated with daily exposure to genotoxic xenobiotics.

The Pharmacological Activities of Crocus sativus L.: A Review Based on the Mechanisms and Therapeutic Opportunities of its Phytoconstituents

Crocus species are mainly distributed in North Africa, Southern and Central Europe, and Western Asia, used in gardens and parks as ornamental plants, while Crocus sativus L. (saffron) is the only species that is cultivated for edible purpose. The use of saffron is very ancient; besides the use as a spice, saffron has long been known also for its medical and coloring qualities. Due to its distinctive flavor and color, it is used as a spice, which imparts food preservative activity owing to its antimicrobial and antioxidant activity. This updated review discusses the biological properties of Crocus sativus L. and its phytoconstituents, their pharmacological activities, signaling pathways, and molecular targets, therefore highlighting it as a potential herbal medicine. Clinical studies regarding its pharmacologic potential in clinical therapeutics and toxicity studies were also reviewed. For this updated review, a search was performed in the PubMed, Science, and Google Scholar databases using keywords related to Crocus sativus L. and the biological properties of its phytoconstituents. From this search, only the relevant works were selected. The phytochemistry of the most important bioactive compounds in Crocus sativus L. such as crocin, crocetin, picrocrocin, and safranal and also dozens of other compounds was studied and identified by various physicochemical methods. Isolated compounds and various extracts have proven their pharmacological efficacy at the molecular level and signaling pathways both in vitro and in vivo. In addition, toxicity studies and clinical trials were analyzed. The research results highlighted the various pharmacological potentials such as antimicrobial, antioxidant, cytotoxic, cardioprotective, neuroprotective, antidepressant, hypolipidemic, and antihyperglycemic properties and protector of retinal lesions. Due to its antioxidant and antimicrobial properties, saffron has proven effective as a natural food preservative. Starting from the traditional uses for the treatment of several diseases, the bioactive compounds of Crocus sativus L. have proven their effectiveness in modern pharmacological research. However, pharmacological studies are needed in the future to identify new mechanisms of action, pharmacokinetic studies, new pharmaceutical formulations for target transport, and possible interaction with allopathic drugs.

Inhibition of Melanosis in Whiteleg Shrimp (Litopenaeus vannamei) during Refrigerated Storage Using Extracts of Different Avocado (Persea americana Mill.) By-Products

Melanosis in shrimp usually leads to reduction in its shelf life and quality, which causes a significant loss in economic value of shrimp products. This study reports potential applications of nine ethanolic extracts of by-products, i.e., peel and/or seed from three Vietnamese avocado varieties as effective inhibitors of melanosis in whiteleg shrimp. Six out of nine shrimp samples treated with the prepared extracts (0.025%, w/v) reduced melanosis and lipid oxidation more significantly as compared to those treated with sodium metabisulfite (SMS, 1.25%, w/v) and control groups (treated with water) during 8-day storage at 4°C (P<0.05). These six extracts had mean gray values ranging from 47.0±0.7 to 57.3±0.4% were lower than those treated with SMS (mean gray of 39.8±0.4%). The inhibition of melanosis and lipid oxidation in shrimp for these extracts could be attributed to their high content of polyphenols [total phenolic content (TPC) from 44.5±1.1 to 144.7±1.9 mg gallic acid equivalents/g dried weight] and strong antioxidant activities [including 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ferric reducing antioxidant power (FRAP), and tyrosinase enzyme inhibition]. Pearson statistical analysis showed strong correlation for melanosis inhibition to TPC and DPPH scavenging (r>0.80) followed by tyrosinase inhibition and FRAP (r>0.50). The findings obtained from this study suggest potential utilization of avocado by-product extracts as safe and cheap natural alternatives to traditional sulfites for anti-melanosis and shelf life extension of whiteleg shrimp.

Antimicrobial Activity and Chemical Characterization of a Non-Polar Extract of Saffron Stamens in Food Matrix

The production of saffron spice generates large quantities of plant by-products: over 90% of the plant material collected is discarded, and a consideration fraction of this waste is plant stamens. This work investigated the chemical composition and the antimicrobial activities of the non-polar fraction extracted from four different saffron flower stamens. The chemical composition of ethereal extracts of the saffron stamens was qualitatively assessed by means of gas-chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) analyses. These analyses revealed ethereal extracts to possess a high polyunsaturated fatty acid content. In vitro antibacterial activity of stamen extracts showed no large differences between Gram-positive and Gram-negative bacteria in terms of minimal inhibitory concentration (MIC). In food matrix microbial analysis of the bacterial strains belonging to the main foodborne pathogen species, including Staphylococcus aureus DSM 20231, Escherichia coli DSM 30083, and Listeria monocytogenes DSM 20600, using low-fat UHT milk, revealed a statistically significant reduction in the number of cells (particularly for E. coli and S. aureus with a complete elimination of the population of the two target bacteria following incubation in diethyl ether extracts of saffron stamen (DES) at high concentrations tested, both at 37 °C and 6 °C (for 48 h and 7 days, respectively). A synergic effect was observed when the pathogens were incubated at 6 °C with DES. This work shows these by-products to be excellent sources of bioactive compounds, which could be exploited in high-added-value products, such as food, cosmetics, and drugs.

Antioxidant, Antimicrobial, Antidiabetic and Cytotoxic Activity of Crocus sativus L. Petals

The purpose of this research is to examine in vitro antioxidant, antimicrobial, antidiabetic and cytotoxic efficacy of different extracts of Crocus sativus L. petals. Antioxidant activity of extracts was assessed by DPPH and ABTS (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) assay. Among all extracts, ethanol (SPE) had the maximum radical scavenging activity with IC50 values 86.63 ± 7.53 μg/mL. The antimicrobial activity was determined by the evaluation of the minimum inhibitory concentration using the agar well plate procedure. The most effective extract was SPE with a minimum inhibitory concentration varying between 500 µg/mL, 250 µg/mL, 125 µg/mL, 62.5 µg/mL, 31.25 µg/mL, 15.63 µg/mL. Cytotoxic activity was tested against MDA-MB-231 cell lines using the MTT method whereas, antidiabetic activity was evaluated using an alpha-glucosidase inhibition assay. All extracts were found to have significant antidiabetic activity.

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.

Crocus sativus by-products as sources of bioactive extracts: Pharmacological and toxicological focus on anthers

Multiple studies revealed the potential application of high quality saffron byproducts as cheap sources of bioactive compounds endowed with antioxidant activity. In the present study, we analyzed the total fatty acids of the anthers, and explored the pharmacological and toxicological potential of anthers, by evaluating genotoxic and protective effects in multiple cell lines, brine shrimps and isolated rat tissues. The phytochemical analyses showed that anthers are rich in long chain fatty acids most of which are unsaturated (80.51%). Particularly, anther water extract revealed to be well tolerated by multiple cell lines, and able to modulate reactive oxygen species (ROS) levels, without exerting either genotoxic or cytotoxic effects. The same extract was also able to blunt lipopolysaccharide (LPS)-induced nitrite and malondialdehyde (MDA) in isolated rat tissues. On the other hand, considering the concomitant null effect on HCT116 cell migration, in wound healing experimental paradigm, our findings suggest the efficacy of water anther extract as protective agent without any direct reverting effects on lesioned tissues. Concluding, the promising results, deriving from the pharmacological and toxicological evaluations, support the valorization of saffron anthers as a strategy to optimize and develop the productive chain of Abruzzo saffron.

Crocus sativus L. stigmas and byproducts: Qualitative fingerprint, antioxidant potentials and enzyme inhibitory activities

Saffron (Crocus sativus L.) has been previously reported to be active as a protective agent in multiple experimental models of oxidative stress, inflammation and cancer. These findings refer to the protective effects of stigmas, not byproducts such as tepals and anthers. In this context, the aims of the present work were to characterize the phytochemical profile of saffron stigmas (CST) and high quality byproducts (tepals + anthers - CTA) extracts. Additionally, we studied the antioxidant and chelating effects of CST and CTA extracts by preliminary in vitro assay. The antioxidant activity was further investigated through the evaluation of reactive oxygen species (ROS) levels and lactate dehydrogenase (LDH) activity on mouse myoblast (C2C12) and human colon cancer (HCT116) cell lines. Additionally, we evaluated CST and CTA extract treatment on cholinesterases, α-glucosidase and α-amylase activity, in vitro. Finally, we studied the effects of CST extract on malondialdehyde (MDA) level in rat colon specimens challenged with E. coli lipopolysaccharide (LPS). We observed that water CST extracts are rich in phenolic content, whereas for CTA the olive oil was the elective extraction solvent. As expected, water CST extracts were the most effective in reducing hydrogen peroxide-induced oxidative stress in both cell lines and in vitro assays. Furthermore, both CST and CTA water extracts reduced the LDH activity in HCT116 cells challenged with hydrogen peroxide and LPS-induced MDA levels in rat colon specimens. Concluding, the present findings showed protective effects exerted by CST and CTA extracts in in vitro and ex vivo models of inflammation and oxidative stress.