Roselle (Hibiscus sabdariffa L.) calyces tea improves physical fitness of healthy adults

Roselle calyces (Hibiscus sabdariffa L.) is a plant that contains anthocyanin and flavonoids, which function as exogenous antioxidants for the human body to counteract excess oxidative stress. Roselle has anti-hypertensive, anti-cancer and anti-diabetic effects. The present study evaluated roselle to see whether it affects physical fitness. The components of physical fitness include strength, balance, right and left hand grip, vertical jump and VO2max (maximum oxygen consumption). A total of 30 subjects received 200 ml rosella tea for 30 days every morning and evening. Every week, subjects were assessed for physical fitness. Data analysis used paired t and Wilcoxon test according to the normality test results. The results showed significant improvements in strength (from 24.9 to 27.3 kg; P=0.025), balance (from 23.3 to 42.2 sec; P=0.004), right (from 31.8 to 35.1 kg; P<0.0001) and left hand grip (from 29.8 to 31.6 kg; P=0.020), vertical jump (from 38.6 to 41.1 m/sec; P=0.008) and VO2max (from 31.1 to 34.3 ml/kg/min; P=0.014). This demonstrated that roselle significantly improved six parameters of physical fitness and may be used as a supplement to improve physical fitness without severe side effects.

Evaluating the potential of Hibiscus sabdariffa beverage to address the prevalence of iron deficiency in sub-Saharan Africa

The potential of Hibiscus sabdariffa L. beverage as a dietary iron source for sub-Saharan Africans was investigated. The target was to provide 6 mg of iron through 250 mL of the beverage daily. However, the iron content of the dried hibiscus calyces was determined to be 9.73 ± 0.31 mg/100 g and from that only ∼30% was extractable, resulting in 0.93 ± 0.19 mg Fe/250 mL of the selected beverage formulation. Therefore, ferrous sulfate was explored as a fortificant. The beverage contains polyphenols which could form non-absorbable chelation complexes with iron during digestion. Subsequently, the effect of polyphenols on the bioaccessibility of native and added iron was assessed using spectrophotometric methods. The presence of iron-polyphenol complexes in samples of the unfortified and fortified beverages, adjusted to pH 6.5 (pH at site of iron absorption in the gut) was established. However, only ∼25% of the added iron was found to be bound in the complex. It was shown that the viability of H. sabdariffa L. beverage as an iron source is impacted by extraction losses and the inhibitory effect of polyphenols. Nonetheless, if iron-polyphenol complexation was reduced/prevented then, a fortified hibiscus beverage could be a useful iron source.

Novel Perspectives on Food-Based Natural Antimicrobials: A Review of Recent Findings Published since 2020

Various fruit and vegetable wastes, particularly peels, seeds, pulp, and unprocessed residues from the food industry, are abundant sources of antioxidants and essential antimicrobial agents. These valuable bioactive compounds recovered from the food industry have a great application in food, agriculture, medicine, and pharmacology. Food-derived natural antimicrobials offer advantages such as diminishing microbial loads and prolonging the shelf life of food products particularly prone to microbial spoilage. They not only enrich the foods with antioxidants but also help prevent microbial contamination, thereby prolonging their shelf life. Similarly, incorporating these natural antimicrobials into food packaging products extends the shelf life of meat products. Moreover, in agricultural practices, these natural antimicrobials act as eco-friendly pesticides, eliminating phytopathogenic microbes responsible for causing plant diseases. In medicine and pharmacology, they are being explored as potential therapeutic agents. This review article is based on current studies conducted in the last four years, evaluating the effectiveness of food-based natural antimicrobials in food, agriculture, medicine, and pharmacology.

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.

The Impact of Salt Stress on Plant Growth, Mineral Composition, and Antioxidant Activity in Tetragonia decumbens Mill.: An Underutilized Edible Halophyte in South Africa

Climate change, expanding soil salinization, and the developing shortages of freshwater have negatively affected crop production around the world. Seawater and salinized lands represent potentially cultivable areas for edible salt-tolerant plants. In the present study, the effect of salinity stress on plant growth, mineral composition (macro-and micro-nutrients), and antioxidant activity in dune spinach (Tetragonia decumbens) were evaluated. The treatments consisted of three salt concentrations, 50, 100, and 200 mM, produced by adding NaCl to the nutrient solution. The control treatment had no NaCl but was sustained and irrigated by the nutrient solution. Results revealed a significant increase in total yield, branch production, and ferric reducing antioxidant power in plants irrigated with nutrient solution incorporated with 50 mM NaCl. Conversely, an increased level of salinity (200 mM) caused a decrease in chlorophyll content (SPAD), while the phenolic content, as well as nitrogen, phosphorus, and sodium, increased. The results of this study indicate that there is potential for brackish water cultivation of dune spinach for consumption, especially in provinces experiencing the adverse effect of drought and salinity, where seawater or underground saline water could be diluted and used as irrigation water in the production of this vegetable.

Evaluation of nutritional and elemental compositions of green and red cultivars of roselle: Hibiscus sabdariffa L

Roselle—Hibiscus sabdariffa L. leaves at different stages of growth, calyces and seeds were analyzed for nutritional and anti-nutritional factors. All the treatments contained a good but varied proportion of carbohydrate in a range of 26.93–54.13%, crude protein from 5.7 to 27.06%, crude fat 1.16–13.09%, crude fibre 15.75–36.10%, energy 631.36–1065 kJ, ash 6.08–13.74% and moisture content 6.00–9.7%. The vitamins A, C and E were also found to be present in all the treatments in a different but substantial amount. The calcium, magnesium and iron contents in all the treatments were higher than the recommended daily allowance of 1250, 350, and 15 mg for adults, while the phosphorus and sodium values in all the treatments were below 1000 and 1500 mg RDA for adults. However, the Na + /K + for all the treatments were lower than 1. The values of anti-nutrients in the samples were small except post-flowering red which had high phytate content of 21.02%, although this can be easily reduced during processes like boiling and cooking. Thus, both cultivars of roselle contain high nutritional, elemental, and vitamins compositions and small content of anti-nutrients.