Anthocyanidins and anthocyanins: colored pigments as food, pharmaceutical ingredients, and the potential health benefits

Understanding the genetic regulation of anthocyanin biosynthesis in plants - Tools for breeding purple varieties of fruits and vegetables

Anthocyanins are naturally occurring flavonoids derived from the phenylpropanoid pathway. There is increasing evidence of the preventative and protective roles of anthocyanins against a broad range of pathologies, including different cancer types and metabolic diseases. However, most of the fresh produce available to consumers typically contains only small amounts of anthocyanins, mostly limited to the epidermis of plant organs. Therefore, transgenic and non-transgenic approaches have been proposed to enhance the levels of this phytonutrient in vegetables, fruits, and cereals. Here, were review the current literature on the anthocyanin biosynthesis pathway in model and crop species, including the structural and regulatory genes involved in the differential pigmentation patterns of plant structures. Furthermore, we explore the genetic regulation of anthocyanin biosynthesis and the reasons why it is strongly repressed in specific cell types, in order to create more efficient breeding strategies to boost the biosynthesis and accumulation of anthocyanins in fresh fruits and vegetables.

Flavonoids, Potential Bioactive Compounds, and Non-Shivering Thermogenesis

Obesity results from the body having either high energy intake or low energy expenditure. Based on this energy equation, scientists have focused on increasing energy expenditure to prevent abnormal fat accumulation. Activating the human thermogenic system that regulates body temperature, particularly non-shivering thermogenesis in either brown or white adipose tissue, has been suggested as a promising solution to increase energy expenditure. Together with the increasing interest in understanding the mechanism by which plant-derived dietary compounds prevent obesity, flavonoids were recently shown to have the potential to regulate non-shivering thermogenesis. In this article, we review the latest research on flavonoid derivatives that increase energy expenditure through non-shivering thermogenesis.

Schizosaccharomyces pombe: A Promising Biotechnology for Modulating Wine Composition

There are numerous yeast species related to wine making, particularly non-Saccharomyces, that deserve special attention due to the great potential they have when it comes to making certain changes in the composition of the wine. Among them, Schizosaccharomyces pombe stands out for its particular metabolism that gives it certain abilities such as regulating the acidity of wine through maloalcoholic fermentation. In addition, this species is characterized by favouring the formation of stable pigments in wine and releasing large quantities of polysaccharides during ageing on lees. Moreover, its urease activity and its competition for malic acid with lactic acid bacteria make it a safety tool by limiting the formation of ethyl carbamate and biogenic amines in wine. However, it also has certain disadvantages such as its low fermentation speed or the development of undesirable flavours and aromas. In this chapter, the main oenological uses of Schizosaccharomyces pombe that have been proposed in recent years will be reviewed and discussed.

Isolation of antioxidative compounds from Micromelum minutum guided by preparative thin layer chromatography-2,2-diphenyl-1-picrylhydrazyl (PTLC-DPPH) bioautography method

The application of preparative thin layer chromatography-2,2-diphenyl-1-picrylhydrazyl (PTLC-DPPH) bioautography technique successfully isolated a lignan sesamin (1), two prenylated coumarins (2 and 3) and a marmesin glycosides (4) from Micromelum minutum methanol bark extract. Compounds 2 and 3 were identified as new compounds whereas 1 and 4 were first isolated from Micromelum genus. Structural identification of all compounds were done by detailed spectroscopic analyses and comparison with literature data. Antioxidant capacities of extract, active fraction and compounds were measured based on DPPH free radical savenging activity, oxygen radical absorbance capacity (ORAC) and β-carotene bleaching. The DPPH activity of methanol extract and its fraction present the IC₅₀ values of 54.3 and 168.9 µg/mL meanwhile the β-carotene bleaching results were 55.19% and 5.75% respectively. The ORAC measurements of M. minutum extract, compounds 2 and 4 showed potent antioxidant activity with the values of 5123, 5539 and 4031 µmol TE/g respectively.

Effect of Long-Term Xanthophyll and Anthocyanin Supplementation on Lutein and Zeaxanthin Serum Concentrations and Macular Pigment Optical Density in Postmenopausal Women

Xanthophylls (lutein, L; zeaxanthin, Z) and anthocyanins are often included in food supplements to improve ocular health. There are no dietary reference intakes for them. The aim was to assess the effects of L, Z and anthocyanin supplementation on short and long-term lutein status markers (serum concentration and macular pigment optical density (MPOD)). Seventy-two postmenopausal women were randomized into a parallel study of 8 months: Group A-anthocyanines (60 mg/day); Group X-xanthophylls (6 mg L + 2 mg Z/day); Group X+A-anthocyanines (60 mg/day) + xanthophylls (6 mg L + 2 mg Z/day). At the beginning of the study, 4 and 8 month serum L and Z concentrations were determined (HPLC), as well as L, Z and anthocyanine dietary intake and MPOD (heterochromic flicker photometry). Baseline concentrations of L (0.35 ± 0.19 μmol/L), Z (0.11 ± 0.05 μmol/L), L+Z/cholesterol/triglycerides (0.07 ± 0.04 μmol/mmol) increased in Group X (2.8- and 1.6-fold in L and Z concentrations) and in group XA (2- and 1.4-fold in L and Z concentrations). MPOD (baseline: 0.32 ± 0.13 du) was not modified in any of the groups at the end of the study. There were no differences in the dietary intake of L+Z and anthocyanin at any point in time in any group. Supplementation of L and Z at a dietary level provoked an increase in their serum concentration that was not modified by simultaneous supplementation with anthocyanins.

Ameliorative Influence of Ajwa Dates on Ochratoxin A-Induced Testis Toxicity

Ajwa dates (Phoenix dactylifera), cultivated particularly in Al-Madina Al-Monawarh in Saudi Arabia, and considered as a rich source of natural antioxidants such as anthocyanins, carotenoids and phenolics. It is believed that Ajwa dates have a wide range of protective effects. For this reason, this work aimed to investigate the ameliorative effect of Ajwa dates aqueous extract against ochratoxin A (OTA)-induced testicular lesions in rats. Rats were divided into four groups and treated for 28 days. Group I served as normal control, group II (OTA exposed) treated orally with 289 μg/kg/day. Group III (Ajwa dates aqueous extract) treated orally with 1 g/kg/day. The last group served as the protective group (pretreated with Ajwa dates extract, then OTA). Histological studies revealed that OTA induced lesions in the testicular structure included proliferation of sertoli cells, impairment of some spermatogenesis stages and accumulation of premeiotic germinal cells. However, pretreatment with Ajwa dates extract prevented all the testicular damage and improved spermatogenesis, as well as remarkably enhanced the testicular structure. In conclusion, Ajwa dates aqueous extract has a powerful protective effect and ameliorative influence against OTA- induced testicular damage and may be used to treat sexual impairment and male infertility.

Flavonoids as a Natural Treatment Against Entamoeba histolytica

Over the past 20 years, gastrointestinal infections in developing countries have been a serious health problem and are the second leading cause of morbidity among all age groups. Among pathogenic protozoans that cause diarrheal disease, the parasite Entamoeba histolytica produces amebic colitis as well as the most frequent extra-intestinal lesion, an amebic liver abscess (ALA). Usually, intestinal amebiasis and ALA are treated with synthetic chemical compounds (iodoquinol, paromomycin, diloxanide furoate, and nitroimidazoles). Metronidazole is the most common treatment for amebiasis. Although the efficacy of nitroimidazoles in killing amebas is known, the potential resistance of E. histolytica to this treatment is a concern. In addition, controversial studies have reported that metronidazole could induce mutagenic effects and cerebral toxicity. Therefore, natural and safe alternative drugs against this parasite are needed. Flavonoids are natural polyphenolic compounds. Flavonoids depend on malonyl-CoA and phenylalanine to be synthesized. Several flavonoids have anti-oxidant and anti-microbial properties. Since the 1990s, several works have focused on the identification and purification of different flavonoids with amebicidal effects, such as, -(-)epicatechin, kaempferol, and quercetin. In this review, we investigated the effects of flavonoids that have potential amebicidal activity and that can be used as complementary and/or specific therapeutic strategies against E. histolytica trophozoites. Interestingly, it was found that these natural compounds can induce morphological changes in the amebas, such as chromatin condensation and cytoskeletal protein re-organization, as well as the upregulation and downregulation of fructose-1,6-bisphosphate aldolase, glyceraldehyde-phosphate dehydrogenase, and pyruvate:ferredoxin oxidoreductase (enzymes of the glycolytic pathway). Although the specific molecular targets, bioavailability, route of administration, and doses of some of these natural compounds need to be determined, flavonoids represent a very promising and innocuous strategy that should be considered for use against E. histolytica in the era of microbial drug resistance.

Vermicompost Supplementation Improves the Stability of Bioactive Anthocyanin and Phenolic Compounds in Clinacanthus nutans Lindau

This project studied the effect of vermicompost application on the composition of bioactive anthocyanin and phenolic compounds, and the antioxidant activity of Clinacanthus nutans. The correlation between the bioactive constituents and antioxidant capacity was also evaluated. In this project, a field study was conducted using a randomized complete block design (RCBD) with four treatment groups, including control plants (CC), plants supplied with chemical fertilizer (CF), plants supplied with vermicompost (VC), and plants supplied with mixed fertilizer (MF). The leaves of C. nutans from all treatment groups were harvested, subjected to solvent extraction, and used for quantification of total anthocyanin content (TAC), total phenolic content (TPC), and total flavonoid content (TFC). The initial antioxidant activity of the extracts was evaluated using 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, as well as after two and four weeks of storage at −20 °C and 4 °C. Data analysis showed that CC plants contained the highest TAC (2180.14 ± 338.43 µg/g dry weight) and TFC (276.25 ± 3.09 mg QE/g dry weight). On the other hand, CF plants showed the highest TPC (181.53 ± 35.58 mg GAE/g dry weight). Moreover, we found that CC plants had the highest antioxidant potential against DPPH radicals whereas MF plants showed the lowest antioxidant potential. After four weeks of extract storage at −20 °C and 4 °C, the TPC, TFC, TAC, and antioxidant potential of the extracts decreased. Extracts from VC showed the lowest percentage of total phenolic and total flavonoid loss after extract storage at −20 °C and 4 °C compared with other plant extracts. At this juncture, it could be deduced that the application of vermicompost had little effect on the expression of phenolics, flavonoids, or anthocyanin in C. nutans. However, the extract from plants treated with vermicompost (VC and MF) showed better stability compared with CC and CF after extract storage at different temperatures.

A Randomized, Placebo-Controlled Study on the Safety and Efficacy of Daily Ingestion of Green Tea (Camellia sinensis L.) cv. "Yabukita" and "Sunrouge" on Eyestrain and Blood Pressure in Healthy Adults

The green tea (Camellia sinensis L.) cultivar “Sunrouge” contains anthocyanins, catechins and flavonols. To determine whether ingesting green tea containing anthocyanins improves visual function and blood pressure (BP) in healthy adults, a randomized, double-blind, placebo-controlled study was performed. A total of 120 healthy subjects, aged between 20 and 60 years and with a systolic BP (SBP) value of ≤125 and <155 and a diastolic BP (DBP) value <95, or a DBP of ≤75 mmHg and <95 mmHg and a SBP <155 mmHg, were randomly assigned to one of three groups. For 12 weeks, the placebo group received barley extract without catechin; another group received “Sunrouge” extract containing 11.2 mg anthocyanin and 323.6 mg epigallocatechin-3-O-gallate (EGCG); and a third group received “Yabukita” extract containing 322.2 mg EGCG. Home BP, accommodation ability, visual analog scale questionnaires for eyestrain, and metabolic-associated markers were analyzed at weeks 0, 4, 8, and 12 of the intake period. The ingestion of “Sunrouge” tea significantly improved accommodation ability and eyestrain in subjects younger than 45 years and in subjects who operated visual display terminals every day. It also elevated BP. “Yabukita” tea ingestion significantly increased serum adiponectin levels. No adverse effects were observed. We conclude that long-term intake of “Sunrouge” tea containing anthocyanins and flavonols might improve visual function.

Antibacterial activity and in vivo wound healing potential of phenolic extracts from jaboticaba skin

In this study, different phenolic extracts were obtained from the jaboticaba skin meal (JSM), whose phenolic compounds were characterized and their antibacterial activities were assessed. Moreover, the activity of lyophilized ethanolic extract of jaboticaba skin (EEJS) on wound healing was analyzed in rats. The JSM phenolic extracts were obtained in four ways: aqueous, methanolic, ethanolic, and acetone extracts. The phenolic compounds were characterized in these extracts by high-performance liquid chromatography, and their antibacterial activities were evaluated. The in vivo experiment was divided into four groups and received the following treatments: G1-silver sulfadiazine (positive control); G2-EEJS at 10%; G3-EEJS at 5%, and G4-EEJS at 2.5%. The aqueous extract did not inhibit the growing of any bacterium. The ethanolic, acetone, and methanolic extracts inhibited the growing of all bacteria tested at the concentrations of 1.25%, 2.50%, and 5.00%, respectively. The ethanolic extract was the one that showed the highest bacterial inhibition potential and the highest contents of phenolic compounds, especially of catechin, epicatechin gallate, and epicatechin. The G3 and G4 treatments presented faster wound healing compared to the G1 one, as it promoted a less intense inflammatory reaction and full closure of the wounds at an accelerated rate.

Beneficial Phytochemicals with Anti-Tumor Potential Revealed through Metabolic Profiling of New Red Pigmented Lettuces (Lactuca sativa L.)

The present study aimed to compare polyphenols among red lettuce cultivars and identify suitable cultivars for the development and utilization of healthy vegetables. Polyphenols, mineral elements, and antioxidant activity were analyzed in the leaves of six red pigmented lettuce (Lactuca sativa L.) cultivars; thereafter, we assessed the anti-tumor effects of cultivar B-2, which displayed the highest antioxidant activity. Quadrupole-Orbitrap mass spectrometry analysis revealed four classes of polyphenols in these cultivars. The composition and contents of these metabolites varied significantly among cultivars and primarily depended on leaf color. The B-2 cultivar had the highest antioxidant potential than others because it contained the highest levels of polyphenols, especially anthocyanin, flavone, and phenolic acid; furthermore, this cultivar displayed anti-tumor effects against the human lung adenocarcinoma cell line A549, human hepatoma cell line Bel7402, human cancer colorectal adenoma cell line HCT-8, and HT-29 human colon cancer cell line. Hence, the new red-leaf lettuce cultivar B-2 has a distinct metabolite profile, with high potential for development and utilization of natural phytochemical and mineral resources in lettuces and can be used as a nutrient-dense food product.

Rebelling against the (Insulin) Resistance: A Review of the Proposed Insulin-Sensitizing Actions of Soybeans, Chickpeas, and Their Bioactive Compounds

Insulin resistance is a major risk factor for diseases such as type 2 diabetes and metabolic syndrome. Current methods for management of insulin resistance include pharmacological therapies and lifestyle modifications. Several clinical studies have shown that leguminous plants such as soybeans and pulses (dried beans, dried peas, chickpeas, lentils) are able to reduce insulin resistance and related type 2 diabetes parameters. However, to date, no one has summarized the evidence supporting a mechanism of action for soybeans and pulses that explains their ability to lower insulin resistance. While it is commonly assumed that the biological activities of soybeans and pulses are due to their antioxidant activities, these bioactive compounds may operate independent of their antioxidant properties and, thus, their ability to potentially improve insulin sensitivity via alternative mechanisms needs to be acknowledged. Based on published studies using in vivo and in vitro models representing insulin resistant states, the proposed mechanisms of action for insulin-sensitizing actions of soybeans, chickpeas, and their bioactive compounds include increasing glucose transporter-4 levels, inhibiting adipogenesis by down-regulating peroxisome proliferator-activated receptor-γ, reducing adiposity, positively affecting adipokines, and increasing short-chain fatty acid-producing bacteria in the gut. Therefore, this review will discuss the current evidence surrounding the proposed mechanisms of action for soybeans and certain pulses, and their bioactive compounds, to effectively reduce insulin resistance.

Hypoglycemic and hypolipidemic effects of anthocyanins extract from black soybean seed coat in high fat diet and streptozotocin-induced diabetic mice

Black soybean seed coat extract (BSSCE) is a rich source of anthocyanins with multiple health effects. This study was aimed at investigating the composition and hypoglycemic and hypolipidemic effects of BSSCE in vitro and in a high-fat diet and streptozotocin (STZ)-induced diabetic mice. The anthocyanins of BSSCE were identified as cyanidin-3-O-glucoside, delphinidin-3-O-glucoside, and peonidin-3-O-glucoside by HPLC-MS. Results demonstrated that BSSCE exhibited strong inhibitory activities for α-amylase, potent inhibition activity against lipid accumulation in HepG2 cells and protection effect on H2O2-induced oxidative stress-damaged HepG2 cells. The food and water intake, body weight loss, blood glucose and insulin level of BSSCE treatment group were found to be significantly reduced when compared with those of diabetic mice group (p < 0.05). The fasting blood glucose level and insulin level of the BSSCE 400 mg kg-1 group mice significantly decreased by 47.97% and 46.49%, respectively. The oral glucose tolerance and activities of antioxidant enzymes including superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) notably improved (p < 0.05). BSSCE could also ameliorate the atherogenic dyslipidaemia of diabetic mice by remarkably decreasing the content of total cholesterol (T-CHO), total triglyceride (TG), and non-esterified fatty acid (NEFA) and increasing the content of high-density lipoprotein cholesterol (HDL-c) (p < 0.05). BSSCE could protect against liver, kidney and pancreas damages in diabetic mice. This study suggested that cyanidin-3-O-glucoside contributed to BSSCE-induced hypoglycemia and hypolipidemia effects in type 2 diabetes mellitus (T2DM), and BSSCE might be a promising functional food or medicine for T2DM treatment.