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

The Potential of Roselle (Hibiscus sabdariffa) Plant in Industrial Applications: A Promising Source of Functional Compounds

Roselle is an annual botanical plant that widely planted in different countries worldwide. Its different parts, including seeds, leaves, and calyces, can offer multi-purpose applications with economic importance. The present review discusses the detailed profile of bioactive compounds present in roselle seeds, leaves, and calyces, as well as their extraction and processing, to explore their potential application in pharmaceutical, cosmetic, nutraceutical, food and other industries. Roselle seeds with high phenolics, fiber, and protein contents, which are suitable to use in functional food product development. Besides, roselle seeds can yield 17-20% of roselle seed oil with high content of linoleic acid (35.0-45.3%) and oleic acid (27.1- 36.9%). This unique fatty acid composition of roselle seed oil makes it suitable to use as edible oil to offer the health benefits of essential fatty acid. Moreover, high contents of tocopherols, phenolics, and phytosterols were detected in roselle seed oil to provide nutritional, pharmaceutical, and therapeutic properties. On the other hand, roselle leaves with valuable contents of phenols, flavonoids, organic acid, and tocopherols can be applied in silver nanoparticles, food product development, and the pharmaceutical industry. Roselle calyces with high content of anthocyanins, protocatechuic acids, and organic acids are widely applied in food and colorant industries.

Comparative Study on the Chemical Profile, Antioxidant Activity, and Enzyme Inhibition Capacity of Red and White Hibiscus sabdariffa Variety Calyces

Hibiscus sabdariffa L. (Family: Malvaceae) is believed to be domesticated by the people of western Sudan sometime before 4000 BC for their nutritional and medicinal properties. This study aimed to investigate the chemical profile, antioxidant activity, and enzyme inhibition property of extracts from red roselle (RR) and white roselle (WR) varieties grown in Sudan. Three aqueous extracts obtained by maceration, infusion, and decoction, in addition to the methanolic one, were prepared from the two roselle varieties. Results showed that the highest total phenolic and flavonoid contents of RR were obtained from the extracts prepared by infusion (28.40 mg GAE/g) and decoction (7.94 mg RE/g) respectively, while those from the WR were recorded from the methanolic extract (49.59 mg GAE/g and 5.81 mg RE/g respectively). Extracts of RR were mainly characterized by high accumulation of chlorogenic acid (6502.34-9634.96 mg kg-1), neochlorogenic acid (937.57-8949.61 mg kg-1), and gallic acid (190-4573.55 mg kg-1). On the other hand, neochlorogenic acid (1777.05-6946.39 mg kg-1) and rutin (439.29-2806.01 mg kg-1) were the dominant compounds in WR. All extracts from RR had significant (p < 0.05) higher antioxidant activity than their respective WR except in their metal chelating power, where the methanolic extract of the latter showed the highest activity (3.87 mg EDTAE/g). RR extracts prepared by infusion recorded the highest antioxidant values (35.09, 52.17, 65.62, and 44.92 mg TE/g) in the DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), CUPRAC (cupric ion reducing antioxidant capacity), and FRAP (ferric reducing antioxidant power) assays, respectively. All aqueous extracts from the WR exerted significant (p < 0.05) acetylcholinesterase (AChE) inhibitory activity (3.42-4.77 mg GALAE/g; GALAE = galantamine equivalents), while only one extract, obtained by maceration, from RR exerted AChE inhibitory activity (4.79 mg GALAE/g). All extracts of the RR showed relatively higher BChE (butyrylcholinesterase) inhibitory activity (3.71-4.23 mg GALAE/g) than the WR ones. Methanolic extracts of the two roselle varieties displayed the highest Tyr (tyrosinase) inhibitory activity (RR = 48.25 mg KAE/g; WR = 42.71 mg KAE/g). The methanolic extract of RR exhibited the highest amylase (0.59 mmol ACAE/g) and glucosidase (1.46 mmol ACAE/g) inhibitory activity. Molecular docking analysis showed that delphinidin 3,5-diglucoside, rutin, isoquercitrin, hyperoside, and chlorogenic acid exerted the most promising enzyme inhibitory effect. In conclusion, these findings indicated that the chemical profiles and biological activity of roselle varied according to the variety, extraction solvent, and technique used. These two roselle varieties can serve as a valuable source for the development of multiple formulations in food, pharmaceutical, and cosmetic industries.

Sustainable aquafeed development: Incorporating select fruit wastes into Zebrafish diets using mathematical model-based approach

Expensive aquafeed is a major problem in aquaculture, creating the need for a low-cost feed that provides ideal nutritional requirement to maximize growth performances. This study aims to formulate and evaluate two new optimized Zebrafish feeds (F1 and F2) using linear programming mathematical model, one of which incorporates two pigment rich fruit wastes (Pitaya peel and Roselle calyx) in the formulation. The model represents nutritional content and cost of each ingredient into linear equations, with the goal of finding ideal combination that satisfies the specific nutrient requirements. By systematically evaluating ingredient proportions, linear programming ensures that Zebrafish receives adequate nutrients at the lowest possible cost, making the feed development process more efficient and cost-effective. The novel feed formulations derived from the mathematical model were tested on the growth and pigmentation of Zebrafish in comparison to a commercial feed (control). Feed intake of F1 and F2 were generally found to be similar to the control feed, indicating the acceptability of the formulated feeds by the Zebrafish. Body weight and length of Zebrafish fed with F1 and F2 were comparable to Zebrafish fed with control feed (p > 0.05). Similarly, Zebrafish fed with F1 and F2 showed no significant differences in pigment intensity compared to Zebrafish fed with control feed (p > 0.05). The survival rate of fishes in all feeding groups were greater than 70 % with no significant differences (p > 0.05). Results obtained in this study illustrated the potential of mathematic linear programming and effectiveness of utilising pigment-rich fruit wastes in formulating an optimized economic aquafeed.

Preparation and Characterisation of Acid-Base-Change-Sensitive Binary Biopolymer Films with Olive Oil and Ozonated Olive Oil Nano/Microcapsules and Added Hibiscus Extract

The purpose of this study was to develop and characterise bionanocomposites based on chitosan (CHIT) and alginate (ALG) in two series, which were subsequently functionalised with emulsions based on a combination of water, oil, ozonated oil and hibiscus flower extracts. The structure and morphology of the materials produced were characterised by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and ultraviolet and visible light (UV-Vis) absorption spectroscopy, along with a surface colour analysis and the determination of the mechanical and thermal properties of the resulting composites. Functionalisation did affect the analysed composite parameters. The FTIR spectra indicated that the polysaccharide matrix components were compatible. The SEM images also confirmed the presence of nano/microcapsules in the polysaccharide matrix. The obtained results indicate that the order of adding polysaccharides has a significant impact on the encapsulation capacity. The encapsulation resulted in the improved thermal stability of the composites. The emissions analysis showed that the composites containing nano/microcapsules are characterised by a higher emission intensity and are sensitive to acid or base changes. Significant differences in emission intensity were observed even at low concentrations of acids and bases. A drop in the mechanical properties was observed following functionalisation. The results of this study suggest that these bionanocomposites can be used as active and/or smart packaging materials.

Therapeutic Potential of Hibiscus sabdariffa Linn. in Attenuating Cardiovascular Risk Factors

Cardiovascular diseases (CVDs) represent a broad spectrum of diseases afflicting the heart and blood vessels and remain a major cause of death and disability worldwide. CVD progression is strongly associated with risk factors, including hypertension, hyperglycemia, dyslipidemia, oxidative stress, inflammation, fibrosis, and apoptosis. These risk factors lead to oxidative damage that results in various cardiovascular complications including endothelial dysfunctions, alterations in vascular integrity, the formation of atherosclerosis, as well as incorrigible cardiac remodeling. The use of conventional pharmacological therapy is one of the current preventive measures to control the development of CVDs. However, as undesirable side effects from drug use have become a recent issue, alternative treatment from natural products is being sought in medicinal plants and is gaining interest. Roselle (Hibiscus sabdariffa Linn.) has been reported to contain various bioactive compounds that exert anti-hyperlipidemia, anti-hyperglycemia, anti-hypertension, antioxidative, anti-inflammation, and anti-fibrosis effects. These properties of roselle, especially from its calyx, have relevance to its therapeutic and cardiovascular protection effects in humans. This review summarizes the findings of recent preclinical and clinical studies on roselle as a prophylactic and therapeutic agent in attenuating cardiovascular risk factors and associated mechanisms.

The Management of Diabetes Mellitus Using Medicinal Plants and Vitamins

Diabetes mellitus (DM) is a serious chronic metabolic disease that is associated with hyperglycemia and several complications including cardiovascular disease and chronic kidney disease. DM is caused by high levels of blood sugar in the body associated with the disruption of insulin metabolism and homeostasis. Over time, DM can induce life-threatening health problems such as blindness, heart disease, kidney damage, and stroke. Although the cure of DM has improved over the past decades, its morbidity and mortality rates remain high. Hence, new therapeutic strategies are needed to overcome the burden of this disease. One such prevention and treatment strategy that is easily accessible to diabetic patients at low cost is the use of medicinal plants, vitamins, and essential elements. The research objective of this review article is to study DM and explore its treatment modalities based on medicinal plants and vitamins. To achieve our objective, we searched scientific databases of ongoing trials in PubMed Central, Medline databases, and Google Scholar websites. We also searched databases on World Health Organization International Clinical Trials Registry Platform to collect relevant papers. Results of numerous scientific investigations revealed that phytochemicals present in medicinal plants (Allium sativum, Momordica charantia, Hibiscus sabdariffa L., and Zingiber officinale) possess anti-hypoglycemic activities and show promise for the prevention and/or control of DM. Results also revealed that intake of vitamins C, D, E, or their combination improves the health of diabetes patients by reducing blood glucose, inflammation, lipid peroxidation, and blood pressure levels. However, very limited studies have addressed the health benefits of medicinal plants and vitamins as chemo-therapeutic/preventive agents for the management of DM. This review paper aims at addressing this knowledge gap by studying DM and highlighting the biomedical significance of the most potent medicinal plants and vitamins with hypoglycemic properties that show a great potential to prevent and/or treat DM.

Antioxidant and Antiradical Activities of Hibiscus sabdariffa L. Extracts Encapsulated in Calcium Alginate Spheres

The interest in natural sources with high antioxidant powder has recently increased in several sectors. Ionic gelation methods could be used to protect bioactive substances to control the kinetics and release of these ingredients to the food matrix. This study dealt with the evaluation of the antioxidant capacity and scavenging activity of extracts of Hibiscus Sabdariffa L. (HSL) (with 50% ethanol) encapsulated in calcium alginate spheres as a new source for preserving food against oxidative damage. Their antioxidant activity was measured in different o/w emulsions in which HSL spheres reduced the formation of hydroperoxides (~80%) and thiobarbituric-acid-reactive substance products (~20%). The scavenging activity of HSL extracts was measured in different food simulants (water, water acidified with 3% acetic acid, ethanol at 50%, and pure ethanol), and corresponded to 0.20–0.43, 0.31–0.62, and 11.13–23.82 mmol Trolox/mL extract for Trolox equivalent antioxidant capacity (TEAC), 2,2-diphenylpicrylhydrazyl (DPPH), and oxygen radical absorbance capacity (ORAC) assays, respectively. In general, the best antiradical activity was observed in the ethanolic and acidified mediums, in which the highest concentration of released polyphenols ranged from 0.068 to 0.079 mg GAE/mL. This work indicates the potential of alginate spheres for encapsulating antioxidant compounds as an innovative strategy for several industrial applications.

Synergistic Antibacterial Proficiency of Green Bioformulated Zinc Oxide Nanoparticles with Potential Fosfomycin Synergism against Nosocomial Bacterial Pathogens

The drug resistance of bacterial pathogens causes considerable morbidity and death globally, hence there is a crucial necessity for the development of effective antibacterial medicines to address the antibacterial resistance issue. The bioprepared zinc oxide nanoparticles (ZnO-NPs) were prepared utilizing the flower extract of Hibiscus sabdariffa and then characterized using different physicochemical techniques. The antibacterial effectiveness of the bioprepared ZnO-NPs and their synergism with fosfomycin were evaluated using disk diffusion assay against the concerned pathogens. Transmission electron microscopy (TEM) investigation of the bioprepared ZnO-NPs showed that their average particle size was 18.93 ± 2.65 nm. Escherichia coli expressed the highest sensitivity to the bioinspired ZnO-NPs with a suppressive zone of 22.54 ± 1.26 nm at a concentration of 50 µg/disk, whereas the maximum synergistic effect of the bioinspired ZnO-NPs with fosfomycin was noticed against Klebsiella pneumoniae strain with synergism ratio of 100.29%. In conclusion, the bioinspired ZnO-NPs demonstrated significant antibacterial and synergistic efficacy with fosfomycin against the concerned nosocomial bacterial pathogens, highlighting the potential of using the ZnO NPs-fosfomycin combination for effective control of nosocomial infections in intensive care units (ICUs) and health care settings. Furthermore, the biogenic ZnO-NPs’ potential antibacterial action against food pathogens such as Salmonella typhimurium and E. coli indicates their potential usage in food packaging applications.

Use of Roselle Calyx Wastes for the Enrichment of Biscuits: An Approach to Improve Their Functionality

The objective of the present study was to evaluate the use of powder made out of Roselle Calyx Wastes (RCP) in developing a biscuit formulation with acceptable sensory value. Roselle calyxes were infused in water in a 1:10 ratio. The residual infused calyxes were dried at 50 °C for 16 h, grounded, sieved through a 50 mesh, and stored in plastic bags until used. The biscuit formulations were enriched with RCP at 0% (BC), 5% (BRCP5), 10% (BRCP10), and 15% (BRCP15). The amount of RCP added to the biscuit formulation did not change the protein content. However, the addition of RCP significantly affected the biscuit’s color; the lightness parameter (L*) decreased as the RP content increased from 69.66 to 49.04. The sensory evaluation showed that the control biscuit and the biscuit enriched with 5% of RP were the best accepted. As for the antiradical activity, the formulation with the highest activity was presented by the BRCP15 (587.43 µmol Trolox/100 g dwb). On the other hand, BRCP5 presented 189.96 µmol Trolox/100 g dwb. Therefore, the biscuit formulation with RCP at a 15% enrichment could be used to commercialize a functional product.

Modelling and optimisation of ultrasound-assisted extraction of roselle phenolic compounds using the surface response method

Extracts from Hibiscus sabdariffa L. (roselle) have been used traditionally as a food, in herbal medicine, in hot and cold beverages, as flavouring or coloring agent in the food industry. In vitro and in vivo studies and trials provide evidence, but roselle is poorly characterised phytochemically due to the extraction processes. The optimization of the extraction of phenolic compounds and their antioxidant activities is still a hot topic. In this study, the effect of solute/solvent ratio (33, 40 and 50 mg/mL), extraction temperature (40, 50 and 60 °C) and extraction time (30, 60 and 90 min) was evaluated through the content of phenolic compounds and antioxidant activity. A response surface methodology through a Box-Behnken design was applied and model fit, regression equations, analysis of variance and 3D response curve were developed. The results showed that TPC, TFC, DPPH and FRAP were significantly influenced by temperature, extraction time and solvent/solute ratio. Thus, TPC, TFC, DPPH and FRAP varied from 5.25 to 10.58 g GAE/100 g DW; 0.28 to 0.81 g QE/100 g DW; 0.24 to 0.70 mg/mL; 2.4 to 6.55 g AAE/100 g DW respectively. The optimal experimental condition (41.81 mg/mL; 52.35 °C and 57.77 min) showed a significant positive effect compared to conventional methods. The experimental values at this extraction condition show that this optimization model is technologically, financially and energetically viable as it requires a reasonable concentration, time and temperature.

Antiproliferative effects of dried Moringa oleifera leaf extract on human Wharton's Jelly mesenchymal stem cells

Mesenchymal stem cells (MSCs) have seen an elevated use in clinical works like regenerative medicine. Its potential therapeutic properties increases when used in tandem with complementary agents like bio-based materials. Therefore, the present study is the first to investigate the cytotoxicity of a highly valued medicinal plant, Moringa oleifera, on human Wharton's Jelly mesenchymal stem cells (hWJMSCs) and its effects on the cells' gene expression when used as a pre-treatment agent in vitro. M. oleifera leaves (MOL) were dried and subjected to UHPLC-QTOF/MS analysis, revealing several major compounds like apigenin, kaempferol, and quercetin in the MOL, with various biological activities like antioxidant and anti-cancer properties. We then treated the hWJMSCs with MOL and noticed a dose-dependant inhibition on the cells' proliferation. RNA-sequencing was performed to explain the possible mechanism of action and revealed genes like PPP1R1C, SULT2B1, CDKN1A, mir-154 and CCNB1, whose expression patterns were closely associated with the negative cell cycle regulation and cell cycle arrest process. This is also evident from gene set enrichment analysis where the GO and KEGG terms for down-regulated pathways were closely related to the cell cycle regulation. The Ingenuity pathway analysis (IPA) software further predicted the significant activation of (p < 0.05, z-score > 2) of the G2/M DNA damage checkpoint regulation pathway. The present study suggests that MOL exhibits an antiproliferative effect on hWJMSCs via cell cycle arrest and apoptotic pathways. We believe that this study provides an important baseline reference for future works involving MOL's potential to accompany MSCs for clinical works. Future works can take advantage of the cell's strong anti-cancer gene expression found in this study, and evaluate our MOL treatment on various cancer cell lines.

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.

How to Measure Organic Fruit Consumer Behavior: A Systematic Review

This review article seeks to systematically identify appropriate ways to measure the consumption behavior of organic fruits. The systematic review of the literature was performed according to the criteria of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the eligibility criteria were declared through the PICOS (population, interventions, comparators, outcomes, and study) tool based on 277 article records scientiometrically identified in both the Journal Citation Report databases from Web of Science. The literature review stages determined a reduced set of articles that presented valid and reliable measurement scales that covered determinant constructs in organic fruit consumer behavior (OFCB). The measurement scale with the best results reported within the screened articles covered the constructs related to health, fear, environment, effort, and economy, allowing it to serve as a reference instrument in further studies on food consumer behavior.

Antibacterial kinetics and phylogenetic analysis of Aloe vera plants

Uncontrolled use of antibiotics has resulted in the emergence of resistant bacteria. It has necessitated the evaluation of antibacterial activities and phylo-diversity of Aloe vera (also called Aloe barbadensis) plants as antimicrobial agent in Nigeria. Biotyped enteric bacilli of 251 strains obtained from fecal samples of patients with various gastro-intestinal complications are profiled for antibiogram. Resistant biotypes were assayed for susceptibility to Aloe vera latex and further evaluated for time-kill kinetics and phylo-diversity. More than 30% of enteric bacilli, including Citrobacter freundii, Escherichia coli and Proteus mirabilis were resistant to cotrimoxazole, ciprofloxacin, and tetracycline respectively at MIC >16 µg/ml (p=0.004). Aloe vera latex significantly inhibited 39.5% resistant enteric biotypes with a significant average reduction of the viable count at 1xMIC and 2xMIC to less than 3.0 Log10CFU/mL after 24 hours. Flavonoids, alkaloids, terpenoids and anthraquinine in anti-enteric sap significantly correlated and regressed with antibacterial activity (p<0.05), while two of the antimicrobial Aloe vera plants showed phylogenetic relatedness with other homologous. Anti-bacteria efficacy of some Nigerian Aloe vera latex could provide alternative therapy, while its phylo-diversity and genomic profiling would offer a promising avenue for identification and development of antimicrobial agents as drug candidates for natural antibiotics.