Roselle calyces (Hibiscus sabdariffa), an alternative to the food and beverages industries: a review

Comparative Analysis of Water Extracts from Roselle (Hibiscus sabdariffa L.) Plants and Callus Cells: Constituents, Effects on Human Skin Cells, and Transcriptome Profiles

Roselle (Hibiscus sabdariffa L.) is a plant that has traditionally been used in various food and beverage products. Here, we investigated the potential of water extracts derived from Roselle leaves and callus cells for cosmetic and pharmaceutical purposes. We generated calluses from Roselle leaves and produced two different water extracts through heat extraction, which we named Hibiscus sabdariffa plant extract (HSPE) and Hibiscus sabdariffa callus extract (HSCE). HPLC analysis showed that the two extracts have different components, with nucleic acids and metabolites such as phenylalanine and tryptophan being the most common components in both extracts. In vitro assays demonstrated that HSCE has strong anti-melanogenic effects and functions for skin barrier and antioxidant activity. Transcriptome profiling of human skin cells treated with HSPE and HSCE showed significant differences, with HSPE having more effects on human skin cells. Up-regulated genes by HSPE function in angiogenesis, the oxidation-reduction process, and glycolysis, while up-regulated genes by HSCE encode ribosome proteins and IFI6, functioning in the healing of radiation-injured skin cells. Therefore, we suggest that the two extracts from Roselle should be applied differently for cosmetics and pharmaceutical purposes. Our findings demonstrate the potential of Roselle extracts as a natural source for skincare products.

Optimization of the Extraction of Antioxidant Compounds from Roselle Hibiscus Calyxes (Hibiscus sabdariffa), as a Source of Nutraceutical Beverages

Secondary metabolites from Hibiscus sabdariffa have been used to prevent different diseases. Roselle Hibiscus is known for being rich in phenolic bioactive compounds. The extraction conditions are directly related to the chemical composition and then to the overall bioactivity of the extract. In this study, a Box-Behnken experimental design has been used to optimize the antioxidant activity, considering four variables: ethanol:water ratio, temperature, extraction time, and solvent:solid ratio. The experiment comprises 27 experiments and 3 repetitions at the central point. The results are described by surface response analysis and a second-degree polynomial equation. The model explains 87% of the variation in the response. The maximum antioxidant activity is yielded when 1% solids are extracted in 35.5% ethanol at 60 °C for 33 min. Finally, a nutritional functional supplement of 495 µmol Trolox Equivalent (TE) antioxidant capacity was prepared with the optimized extract.

Can consumption of local micronutrient- and absorption enhancer-rich plant foods together with starchy staples improve bioavailable iron and zinc in diets of at-risk African populations?

Iron and zinc deficiencies remain prevalent in developing countries, often due to monotonous starchy diets that are low in bioavailable minerals. This review addresses the question as to whether consumption of starchy staple foods in Africa together with micronutrient-dense and absorption enhancer-rich plant foods can enhance iron and zinc bioavailability in the diets of at-risk populations. While green leafy vegetables (GLVs) fortification of starchy staples can improve mineral contents, especially iron, it may not improve bioavailable iron and zinc, due to GLVs' high contents of mineral absorption inhibitors, notably polyphenols, phytate and calcium. Fruits, although low in minerals, could improve bioavailable iron and zinc in the staples because of their high ascorbic and citric acid and/or β-carotene contents, which can form soluble chelates with the minerals. More human studies are needed to establish whether such a technology or fortification strategy can improve bioavailable iron and zinc in African-type plant-based diets.

Serum Phospholipids Are Potential Therapeutic Targets of Aqueous Extracts of Roselle (Hibiscus sabdariffa) against Obesity and Insulin Resistance

Roselle (Hibiscus sabdariffa) is rich in phenolic compounds with antiobesogenic and antidiabetic effects. In this study, the effects of aqueous extracts of two varieties of Hibiscus sabdariffa, Alma blanca (white-yellow color) and Cuarenteña (purple color), were evaluated for the prevention of obesity and insulin resistance in rats fed a high-fat and high-fructose diet (HFFD), identifying targeted molecules through global metabolomics. After sixteen weeks, both roselle aqueous extracts prevented body weight gain, and white roselle extract ameliorated insulin resistance and decreased serum free fatty acid levels. Moreover, white roselle extract decreased 18:0 and 20:4 lysophosphatidylethanolamines and purple roselle extract increased 16:0 and 20:4 lysophosphatidylinositol compared to HFFD-fed rats. These results demonstrate that roselle's beneficial health effects are variety-dependent. Interestingly, the white roselle extract showed a greater beneficial effect, probably due to its high contents of organic and phenolic acids, though its consumption is not as popular as that of the red/purple varieties.

Modelling the effects of pecan nut [Carya illinoinensis (Wangenh.) K.Koch], roselle (Hibiscus sabdariffa L.), and salt on the quality characteristics of beef patties

The meat industry has become increasingly interested in developing products containing new ingredients oriented to consumers’ health. Health benefits are gained from frequent consumption of pecan nut and roselle, which can therefore be used as ingredients in meat product formulations. However, incorporating novel ingredients or reducing the content of traditional ingredients might affect meat product quality, thus needs to be evaluated and optimised for the development of functional foods. The objective of the present work was to assess how pecan nut (0 to 10%), roselle (0 to 2%), and salt (0 to 2%) affect the physicochemical properties, antioxidant, and sensory characteristics of beef patties, and use response surface methodology to optimise the content of these ingredients in a meat product formulation. Regression models were developed to predict quality properties. All models were significant (p < 0.05) with an R2 > 0.85 and a nonsignificant lack of fit (p > 0.05), thus indicating that these models could adequately predict response variables. The optimised formulation was 7.97% pecan nut, 1.59% roselle, and 1.08% salt. The predicted physicochemical properties were L* = 42.88, a* = 12.29, b* = 8.51, pH = 5.10, and cooking loss = 24.66%; the antioxidant properties were DPPH = 0.53 mg TE/g fp, ABTS = 0.65 mg TE/g fp, and total phenolic content = 0.46 mg GA/g fp; and the sensory properties were flavour = 7.03, tenderness = 6.98, and juiciness = 7.01. Pecan nut and roselle are promising natural ingredients that can be used to prepare low-salt beef patties.

Hibiscus sabdariffa in Diabetes Prevention and Treatment—Does It Work? An Evidence-Based Review

Diabetes is currently a global health problem that is already reported as an epidemic. This metabolic disease, characterized by a disturbance in the carbohydrate, protein, and lipid metabolism, is often accompanied by disorders of several organs. Its treatment is expensive and often difficult to control. Therefore, it seems necessary to search for new drugs and solutions to facilitate therapy and reduce treatment costs. Herbal medicines are becoming more and more popular. Hibiscus sabdariffa (roselle) is a plant that grows wild in a tropical climate. It has been used in folk medicine for thousands of years. Thanks to the numerous active compounds, including polyphenols, polysaccharides, organic acids, or pectins, it is reported to exhibit hypoglycemic, antioxidant, hypotensive, and anti-lipidemic activities and numerous indirect effects that are related to them. The aim of this review was to update the knowledge about the therapeutic effects of roselle in diabetes and its comorbidities based on in vitro, animal, and human studies. After a careful analysis of the scientific literature, it can be stated that roselle is a promising product that can be used either on its own or as an addition to the conventional treatment regimens to prevent or treat diabetes and its accompanying diseases.

Use of Hibiscus sabdariffa Calyxes in Meat Products

In the search for new ingredients that counteract some of the problems associated with the consumption of meat and meat products like high contents of saturated fat, salt, cholesterol, the absence of dietary fiber, and the presence of synthetic additives, Hibiscus sabdariffa calyxes have shown good colorant, antimicrobial, and antioxidant properties. This research paper studies the use of H. sabdariffa roselle calyxes directly or by means of extracts in meat and meat products. Although its application is incipient, the results are promising. The vibrant red color of the calyxes makes calyxes suitable for their use in meat products even though the concentration must be optimized since the acid taste can detract from the overall acceptance. The antimicrobial properties contribute to safer meat products, and antioxidant effects, helping to extend the shelf life of meat products and reducing oxidative processes. Nonetheless, achieving the desired effects is still challenging since several factors can affect these functional properties.

Identification of anthocyanic profile and determination of antioxidant activity of Dahlia pinnata petals: A potential source of anthocyanins

In recent decades, the food industry has focused on the search for potential sources of anthocyanins that are able to provide color to replace synthetic dyes and at the same time provide health benefits through food products. Thus, in the present work, we propose the Dahlia pinnata flower as a potential source of anthocyanins. The dahlia is a native, annual flower from Mexico with a wide diversity of shapes and colors. The ancestral use of the flower in several dishes, its abundance, and the intense color of the flowers known as black make the D. pinnata flower a suitable candidate to be considered as a potential source of anthocyanins. Thus, the aim of this research is the determination of its nutritional composition, anthocyanin profile, and antioxidant activity. For this purpose, proximate composition of petals was determined by the AOAC standard methods. Anthocyanins were extracted from the dried petals of the flower with 0.1% HCl in methanol and 70% aqueous acetone solution and purified through Amberlite-XAD7-HP resin. Then, the purified extracts were analyzed for antioxidant activity by the DPPH method and the anthocyanin profile was characterized by HPLC and UPLC-MS/MS. Results showed that D. pinnata flowers have a proximate composition similar to other important edible flowers with a high level of moisture (87%-92%) and fiber (6%-7%). The antioxidant activity of both purified extracts was considerable (2.6-12 g/ml) compared to other sources of anthocyanins. The anthocyanin profile of the purified extracts contains four main anthocyanins: delphinidin-3-glucoside, delphinidin-3-rutinoside, pelargonidin-3-sambubioside-5-glucoside, and peonidin-3-sambubioside-5-glucoside, the last two being uncommon as major anthocyanin components in other plant sources. PRACTICAL APPLICATION: We present a potential and novel source of anthocyanins based on anthocyanin content and antioxidant activity of Dahlia pinnata petals. On the basis of UPLC-MS/MS studies, we identified four main anthocyanins, so this information provides the opportunity to study the source in many areas such as natural pigment stabilization, food additives, and antioxidants.

Roselle (Hibiscus sabdariffa L.) calyx water extract ameliorates isoniazid and rifampicin induced liver and renal injuries in rats

Introduction: Roselle (Hibiscus sabdariffa L.) calyces possess natural antioxidants that may provide therapeutic benefits. This study aimed to investigate the protective effects of Roselle calyx water extract against isoniazid (INH) and rifampicin (RIF) induced liver and renal toxicities.Methods: Male Wistar rats (150-250 g) were designated into five groups: control group, INH-RIF group that was treated with INH-RIF at the toxic doses (50-100 mg/kg for 4 weeks, followed by 100-200 mg/kg for 2 weeks), and Roselle groups that were treated daily with Roselle extract at the doses 62.5, 125, and 250 mg/kg, respectively prior to INH-RIF administration. Blood samples were withdrawn weekly for 6 weeks before removing rats’ livers and kidneys for tissue malondialdehyde (MDA) and histopathological analysis.Results: The results showed all rats in the INH-RIF group experienced marked elevations of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea, creatinine, and tissue MDA levels compared to the controls (P<0.05). In contrast, these biomarkers were maintained at near-normal levels in Roselle extract groups. Significant inflammation and cellular degeneration were found in the liver and renal tissues of the INH-RIF group, which were noticeably reduced with Roselle extract pre-treatment at the dose of 250 mg/kg.Conclusion: It is concluded that Roselle calyx extract can provide protection against liver and renal toxicities induced by INH-RIF administration in rats.

Methodologies in the Analysis of Phenolic Compounds in Roselle (Hibiscus sabdariffa L.): Composition, Biological Activity, and Beneficial Effects on Human Health

Roselle (Hibiscus sabdariffa L.), as an edible flower, has long provided an array of positive effects on human health. This benefit is a result of phenolic compounds that are naturally present mainly in the calyx. Plentiful medicinal remedies and functional foods based on this flower are available worldwide, as supported by the studies of phenolic compounds in recent decades. This paper aims to provide a comprehensive review of the composition, biological activity, and beneficial effects on human health of phenolic compounds in roselle. This review was performed in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. A structured search in the published literature for phenolics compositions in roselle was required prior to the evaluation on the validity of the reported analytical methods. Reliable identification and quantification of phenolic compounds in roselle can be achieved by employing the proper extraction and separation methods. With ample alternative analytical methods discussed here, this review provided an aid for comprehending and selecting the most appropriate method for a particular study. The applications of the analytical methods highlighted indicated that phenolic acids, flavonoids, and their derivatives have been identified and quantified in roselle with a range of biological activities and beneficial effects on human health. It was also disclosed that the composition and concentration of phenolic compounds in roselle vary due to the growth factors, cultivars, and environmental influence. Finally, apart from the research progress carried out with roselle during the last ten years, this review also proposed relevant future works.

Enriching street-vended zobo (Hibiscus sabdariffa) drink with turmeric (Curcuma longa) to increase its health-supporting properties

Street-vended foods are cheap, readily available and have been currently identified as possible means for micronutrient fortification in an effort to prevent malnutrition in developing countries. The effect of enriching street-vended zobo drink (Hibiscus sabdariffa) with turmeric (Curcuma longa) was studied to assess the potential to increase health-supporting properties for its consumers. Two processing methods were tested: boiled turmeric root in zobo and addition of fresh turmeric paste to zobo in different concentrations. Vitamin C in turmeric-fortified zobo ranged from 496-725 μg per 100 mL, delphinidin-3-sambubioside from 52-69 mg per 100 mL, and cyanidin-3-sambubioside from 21-27 mg per 100 mL. Micronutrients ranged from 10.9-14 mg L^-1 and 2.19-2.67 mg L^-1 for iron and zinc, respectively. Folic acid, vitamin C, anthocyanins and iron showed the highest amounts in the 2% boiled turmeric zobo samples. Ferulic acid (0.16-2.03 mg per 100 mL), and chlorogenic acid (20-24 mg per 100 mL) did not show the same statistically significant improvement for 2% boiled turmeric-fortified zobo. The zobo samples with turmeric paste consistently had lower values of vitamins, polyphenols and minerals in comparison with the boiled turmeric-fortified zobo samples. Turmeric-fortified zobo can play a role in a healthy diet by its health-supporting properties. Consumption of a typical one serving of 500 mL (representative packaged bottle size of zobo drink by the street vendors in Nigeria) of turmeric-fortified zobo would contribute 63-88% DV and 18-23% DV of iron and zinc. Overall, fortification with boiled turmeric improves the antioxidant and nutritional quality of zobo, specifically regarding vitamin C, delphinidin-3-sambubioside and iron.

Effect of sour tea supplementation on liver enzymes, lipid profile, blood pressure, and antioxidant status in patients with non-alcoholic fatty liver disease: A double-blind randomized controlled clinical trial

The aim of this study was to evaluate the efficacy of sour tea supplementation in patients with nonalcoholic fatty liver disease (NAFLD). Seventy NAFLD patients were enrolled in this randomized, double-blind, placebo-controlled clinical trial. Participants received sour tea in the form of a 450 mg capsule or a placebo capsule daily for 8 weeks. Anthropometric indices, liver enzymes, lipid profile, blood pressure, and antioxidant status were evaluated at the baseline and at the end of the study. Sixty-one participants completed the study. After 8 weeks, sour tea administration significantly decreased serum triglyceride (TG) (p = .03), alanine aminotransferase (ALT) (p = .01), and aspartate aminotransferase (AST) (p = .004) levels compared with the placebo. In addition, sour tea supplementation resulted in a significant reduction in systolic blood pressure (SBP) (p = .03) and diastolic blood pressure (DBP) (p = .04), and a significant increase in serum total antioxidant capacity (TAC) levels (p ˂ .001) compared with the placebo. However, no significant changes in anthropometric measures, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c) levels were observed after sour tea supplementation compared with the placebo (p > .05). Sour tea supplementation may be effective in improving serum TG, liver enzymes, and blood pressure in patients diagnosed with NAFLD. Further studies are needed to address the exact mechanism of action of these effects.

In Vitro Antibacterial Activity of Hibiscus sabdariffa L. Phenolic Extract and Its In Situ Application on Shelf-Life of Beef Meat

Compounds from spices and herbs extracts are being explored as natural antibacterial additives. A plant extract used in traditional folk medicine is Hibiscus sabdariffa L., also known as Roselle. Therefore, the potential use of a phenolic hibiscus extract as antibacterial or natural food preservative was analyzed in vitro and in situ. A phenolic extract was obtained from hibiscus calyces and fractionated, and then the fractions were tested against foodborne pathogen bacteria. Liquid–liquid extraction and solid-phase extraction were used to fractionate the hibiscus extract, and HPLC was employed to analyze the fractions’ phenolic composition. Minimum bactericidal concentration (MBC) and minimal inhibitory concentration (MIC) were calculated for brute hibiscus phenolic extract, each of the fractions and pure commercial phenolic compounds. Bacteria tested were Escherichia coli, Salmonella enterica serovar Typhimurium, Staphylococcus aureus, Listeria monocytogenes and Bacillus cereus. The fraction obtained after liquid–liquid extraction presented the best performance of MBC and MIC against the bacteria tested. Furthermore, a hibiscus ethanolic extract was employed as a natural preservative to extend the shelf-life of beef. Microbiological, color and sensory analyses were performed to the meat during the shelf-life test. The application of the phenolic hibiscus extract also showed an increase of the duration of the meat`s shelf life.

Ultrasound assisted extraction of hibiscus (Hibiscus sabdariffa L.) bioactive compounds for application as potential functional ingredient

The ultrasound assisted extraction (UAE) of total anthocyanins (TA) and total phenolic compounds (TP) from hibiscus calyces was evaluated with the intention of using the extract in future food products. The Box-Behnken Design was used for the extraction evaluating sonication time, solvent concentration and temperature. Final results suggest that 45 min, 65 °C and 25% ethanol can be considered the best region for UAE extraction. The relative area of the peaks identified by UPLC-MS/MS in the extract obtained by the UAE are superior in 2 or even 4 times those obtained by conventional extraction, for all the compounds, suggesting that the UAE method is more effective in the extraction of bioactive compounds. The extract obtained was used to make jelly and submitted to in vitro digestion and colonic fermentation. Loss of TP, TA and antioxidant activity in the jelly with addition of extract was lower when compared to extract loss itself, showing that it is feasible the hibiscus extract application in food products.

Utilization of by-products of Hibiscus sabdariffa L. as alternative sources for the extraction of high-quality pectin

The by-products of Hibiscus sabdariffa L. (HsL), obtained after soaking or decoction of the calyces of Colima and Sudan cultivars, were used for pectin extraction. After soaking, the wastes of both cultivars gave higher yields of pectin than those obtained by decoction. The pectin of the wastes by soaking presented high methoxyl groups, galacturonic acid content, viscosity and gelling capacity. Pectin of this treatment also exhibited bands in the regions of 1750 cm-1 and 1630 cm-1 that represents the C=O stretching vibrations of methyl ester and the amounts and degree of esterification of the HsL pectin. Interestingly, the pectin retained the typical red color of fresh HsL calyces. The amounts of anthocyanins and ascorbic acid of pectin did not show effects against pathogenic microorganisms. Nonetheless, pectin of the Sudan HsL wastes obtained by soaking, exhibited higher properties than those of the citric pectin, thus, demonstrating its potential for industrial applications.

Herbal products containing Hibiscus sabdariffa L., Crataegus spp., and Panax spp.: Labeling and safety concerns

Herbs have been used from ancient times for infusion preparation based on their potential health effects. In particular, the consumption of Hibiscus sabdariffa L., Crataegus spp. and Panax spp. has been largely associated to cardiovascular benefits. In this work, the label information of 52 herbal products for infusion preparation containing the referred herbs was analyzed and discussed, taking into consideration the European Union regulation for herbal products, which intends to protect public health and harmonize the legal framework in Member States. Details about the cardiovascular-related statements and warning notifications about consumption were considered. Also, regulatory issues and possible herb-drug interactions were explored and discussed. A total of 14 of the 52 herbal products selected presented health claims/statements on the label. Hibiscus was present in the majority of the products and, in some cases, it was mentioned only in the ingredients list and not on the product front-of-pack. Despite the promising outcomes of these plants to modulate cardiovascular risk markers, consumers with some sort of cardiovascular dysfunction and/or under medication treatments should be aware to carefully analyze the labels and consult additional information related to these herbal products. Manufacturers have also a huge responsibility to inform consumers by presenting awareness statements. Lastly, health professionals must advise and alert their patients about possible interactions that could occur between the concomitant consumption of drugs and herbs. Overall, there is still a real need of additional studies and clinical trials to better understand herbs effects and establish a science-based guidance to assess their safety.

Antioxidant characteristics of extracts of Hibiscus sabdariffa calyces encapsulated with mesquite gum

This study compared the stability of extracts of H. sabdariffa calyces microencapsulated with different concentrations of mesquite gum during storage. Dry Roselle calyces were mixed with 50:50 (v/v) ethanol:water solution to obtain 18°Bx concentrate. This Roselle extract concentrate was mixed with purified mesquite gum (100:1-100:5 v/w). The Roselle extract concentrate-gum (RECG) was spray dried at inlet and outlet temperatures of 180 ± 2 and 104 ± 2.3 °C, respectively, at an air flow rate of 38 m³/h. Encapsulated Roselle powders (ERP) were analyzed for moisture content, total monomeric anthocyanins (differential pH), phenolic compounds (Folin and Ciocalteu method), antioxidant capacity (ABTS), and color parameters ([Formula: see text], and [Formula: see text]) after 5 weeks and 1 year of storage. Sorption properties (isotherms) and micrographs of powders were also obtained. The average yield of RECG powders was 15.27 ± 0.81 g/100 mL. During storage, ERP showed average values of phenolic compounds, antioxidant capacity, and anthocyanins of 3.43 ± 0.25 g gallic acid equivalents/100 g, 9.34 ± 1.4 g Trolox equivalents/100 g, and 318.7 ± 20.6 mg cyanidin-O-glycoside/100 g, respectively. Color parameters remained constant along the storage time.