Highlights

  1. Roselleleaf serves as a food component in correction of heart dysfunction through elimination of toxins and unwanted cholesterol from the body.
  2. Roselle leaf is used as medication for persons with AIDS.
  3. Roselle leaf extract has being found to significantly decrease the degree of all types of ulceration.

There has been a massive increase in the demand for natural foods in the last three decades owing to the growing demands for healthier eating and living lifestyles. In view of this, value-added agri-food products rich in many micro and macro nutrients complexes, have become the staple foods consumed both as direct foods and derived foods. The large family Hibiscus has not only featured in these class of nature in high demands but has been used as a food supplement which not only sustains the body but prevent many conventional diseases that have bedeviled the health of many people. With over 300 specie of the plant in existence Hibiscus flower offers an endless variety of uses, both medically and industrially. Hibiscus sabdariffa, also known scientifically as Roselle is a plant flower grown massively as an annual tropical/subtropical plant widely cultivated in the agricultural terrain of Africa, central America, Southeast Asia and South America.

Hibiscus is a genus of flowering plants in the mallow family, Malvaceae. The genus is quite large, comprising several hundred species that are native to warm temperate, subtropical and tropical regions throughout the world. Member species are renowned for their large, showy flowers and those species are commonly known simply as “hibiscus”, or less widely known as rose mallow. Other names include hardy hibiscus, rose of sharon, and tropical hibiscus. (wikipedia)

Hibiscus is embedded with red, fleshy and juicy calyces which enhances its nutritional and commercial value over the globe.

Hibiscus contains numerous bioactive compounds, such as polyphenols, organic acids and vitamins A, C, and E (Da-Costa-Rocha et al., 2014). These properties earned it its potential health benefits as it abounds in analgesic memory enhancement, anti-inflammatory substances, antioxidant anti-microbial, antimodulatory, hepatoprotective, anticarcinogenic effects, relief of oxidative stress, prevention of cardiovascular diseases, and control of diabetes (Zhen et al., 2016). Traditionally, Hibiscus flowers has been reported to possess antitumor properties, as well as have been used as analgesic, antipyretic, anti-asthmatic, and anti- inflammatory agents. Research on extracts of stems, roots, leaves, and flowers from Hibiscus have revealed that its photochemical components contributed to beneficial findings to human’s health. Current scientific literature suggests that more than 50% of today’s clinical medications were of natural product origin. Many of them have played a significant role in pharmacological industry and in developing better therapies for various diseases. This plant is economically very essential owing to the herbal products and medicinal uses Because of insufficient current pharmacological information, there is not much scientific research or clinical trials conducted on the chemical extracts.

Nature of Roselle leaf

The Zobo Leaf, scientifically known as Hibiscus sabdariffa, is an annual or perennial herbaceous shrub that is a member of the Malvaceae family (Foline et al., 2011). In English, it is known as Roselle, while in North Africa, it is known as Karkade or Carcade. H. sabdariffa is a herbaceous plant with erect, more or less branched stems that can grow up to 2.5 cm long and 3 cm wide (Baiyeri and Ugese, 2011). It has a deep penetrating tap root and smooth or slightly cylindrical, hispid branches that can be reddish or green in color. Simple alternating leaves with stipules that are up to 1.5 cm long and are narrowly lanceolate to linear. Leaf stalks range in length from 1 to 6 cm (Kumar et al., 2011). The Roselle leaf or leaflet is widely diverse both in shape and size, 3 to 5 palmate veins, a wedge-shaped base, an acute apex, and an oblong-lanceolate lobe that is 5 to 10 cm long. Upper leaves are 3-5 palmatilobed. The faces have a hint of pubescence and occasionally have prickles on the midrib. An oval nectar gland, measuring 2 to 3 mm in length, is present at the beginning of the midrib on the underside (Kumar et al., 2012).

The flowers (Fig. 1) are pentamerous, and solitary in the leaf axils. The corolla is yellow with five large, ovate petals that are 4 to 5 cm long and spotted with purple at the base. The capsule contains 22–34 kidney-shaped seeds that are 3-5 mm long, light to deep brown in color, and covered in minute, stout hair. The stem and leaves are acidic in nature. The fruit’s spherical-conical capsule measure 2–2.5 m in length, and is apiculate at the apex, and is coated in stiff, applied bristles. It is shorter than the calyx. It also involves the accrescent calyx (Aubriot and Knapp, 2022). H. sabdariffa thrives in settings with sandy soil, heavy rainfall, and well-drained soil. Raw Roselle contains some carbohydrates, calcium, magnesium, potassium, vitamin C, and B vitamins. Hibiscus tea (also known as sour tea) tends to be lower in nutrients but still offers many beneficial compounds (Satheesh and Workneh Fanta, 2020). The useful parts of the plant include the leaves and tender shoots, stems, calyces, and seeds. The seeds were found to be a good source of minerals like phosphorus, magnesium and calcium. The young leaves and tender stems of Roselle are consumed raw as green vegetables.

USES

Beverages :  The tea made of the calyces of Hibiscus sabdariffa is known by many names in many countries around the world and is served both hot and cold. The beverage is well known for its red colour, tartness and unique flavor. Additionally, it is highly nutritious because of its vitamin C content.

Food: Dried hibiscus is edible, and it is often a delicacy all over the world. It can also be candied and used as a garnisher, and mostly as usually for desserts in the western worlds.

Drug interactions

It is postulated that H. sabdariffa interacts with diclofenac, chloroquine and acetaminophen by altering the pharmacokinetics. In healthy human volunteers, the H. sabdariffa extract was found to reduce the excretion of diclofenac upon co-administration. Additionally, co-administration of Karkade (H. sabdariffa), a common Sudanese beverage, was found to reduce chloroquine bioavailability. However, no statistically significant changes were observed in the pharmacokinetics of acetaminophen when administered with the Zobo (H. sabdariffa) drink. Further studies are needed to demonstrate clinical significance.

Anti-bacterial actions

There is proof that the calyces of the Roselle have an antibacterial action on a variety of pathogenic microorganisms including Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes, Shigella flexneri, Salmonella Typhimurium, Escherichia coli, and Bacillus anthracis (Abass et al., 2022). Strong antibacterial activity against multidrug resistant A. baumannii is exhibited by the calyces of Roselle (Abdallah, 2016). The calyces of the plant have also been previously reported to possess antibacterial properties against a variety of pathogens, including foodborne pathogens, methicillin-resistant Staphylococcus aureus, Klebsiella pneumonia and Pseudomonas aeruginosa. Saponins, flavonoids, and tannins are antibacterial substances found in hibiscus flowers (Hibiscus rosa-sinensis .) (Abass et al., 2022). By creating intricate molecules against the extracellular proteins of bacterial cells that compromise the integrity of the bacterial cell membrane, flavonoids limit bacterial growth (Donadio et al., 2021). In earlier research, the methanol extract from the calyces of H. sabdariffa substantially inhibited both the non-multidrug resistant and drug resistant strains of A. baumannii, with a zone of inhibition ranging from (11.3–0.3) to (13.6–0.3) mm (Akindahunsi and Olaleye, 2003).

Anti-hypertensive actions

Roselle is effective at reducing both systolic and diastolic blood pressure reported an experiment. The hibiscus tea also known as sour tea was also seen to lower blood pressure in diabetic patients with moderate hypertension (Kafeshani et al., 2017). The extracts of Roselle exhibit antihypertensive effects mediated by three primary processes: ACE inhibition, vasodilation, and diuretic effects. According to results from a the current clinical investigation, sour tea lowered blood pressure in people with stage 1 hypertension (Montalvo-González et al., 2022). After a month, the blood pressure in the control group also dropped, this may have been a result of non-pharmacological approach of losing weight, following the Dietary approaches to stop hypertension (DASH) diet, boosting potassium and decreasing salt intake, as well as engaging in aerobic exercise (Carey et al., 2018). The sour tea has the added benefit of improving lipid profiles and the anthocyanins in Roselle can stop low-density lipoprotein oxidation, which delays the atherosclerotic process (Hajifaraji et al., 2018). Furthermore, Roselle has been shown to contain a compound that causes the release of nitric oxide from the vascular endothelium followed by an increase in renal filtration, a mechanism that counteracts the diuretic action of the plant and decreases blood pressure (Ahmad et al., 2018). Many therapeutic dosages of sour tea have been documented in order to produce its beneficial effects. (Hopkins et al., 2013) conducted one of the first studies examining how Roselle affects blood pressure. Their findings demonstrate that sour tea can lower blood pressure. They further reported that 3 days after the medicine was withdrawn, both systolic and diastolic blood pressure climbed to 7.9% and 5.6%, respectively (Lee and Lee, 2023).

Anticancer

Researchers discovered that Roselle has potentials for use as a chemo-preventive agent in cancer. For instance, anthocyanins present in Roselle have shown ability to caused apoptosis of cancer cells particularly in cases of stomach and leukemia and cancers (Tsai et al., 2014). How well Roselle’s anthocyanins protect against N-nitrosomethylurea (NMU)-induced leukemia in rat models was recently evaluated in an in vivo experiment (Assmann et al., 2021). According to the results, (0.2%) of anthocyanins significantly reduced NMU damage and decreased leukemia by about 33.3%. The results of the experiments also showed that the compounds induced apoptosis in the cells, reduced cell growth and inhibited metastasis and angiogenesis (Assmann et al., 2021). Furthermore, it has been asserted that a diet high in anthocyanins can be utilized to prevent cancer as well as a number of other chronic illnesses (Khan et al., 2021).

The effectiveness of Roselle’s anthocyanins on human skin has also been studied using lymphoma cells that produce delphinidin-3-sambubioside (Hou et al., 2005). Surprisingly, Roselle’s anthocyanins were able to trigger apoptosis in human promyelocytic leukemia (Hou et al., 2005).

In promoting healthy eyes

Zobo contains carotene which the body transforms into vitamin A. The vitamin offers protection to the eyes, supports healthy eyesight, maintains healthy mucous membranes, and prevents age-related eye disorders, making it an antidote to eye problems (Johra et al., 2020).

Boosts the immune system

Vitamin C together with other important vitamins and minerals that strengthen the immune system are abundant in zobo. Regular consumption of zobo will therefore aid in raising the body’s stores of vitamins and essential minerals that support immune system function (Omole and Oranusi, 2019). This pink coloured tea may also help prevent the sniffles according to (Anwar Ibrahim and Noman Albadani, 2014), and the reason been that sour tea includes vitamin C, a potent antioxidant that is in charge of maintaining the health of the immune systems. Moreover, sour tea is high in iron, a mineral that maintains the balance of the immune system and aids in the body’s maintenance of red blood, this same iron’s absorption is improved by vitamin C.

In high blood pressure

Roselle dramatically reduced blood pressure by eliminating extra fluid and enhancing vaso-relaxation in individuals with pre and moderate hypertension according to a 2010 study published in the Journal of Nutrition. In fact, it was claimed that including Roselle in a diet was just as beneficial as taking the well-known anti-hypertensive medication Captropril (Abdel-Rahman et al., 2017). This discovery is significant since it agrees that consuming a beverage like Zobo can lower blood pressure. Medical costs can therefore be saved and the incidence of health challenges like stroke, heart disease, and even death which are associated with high blood pressure can also be prevented especially in a country like Nigeria where over 43% of the population suffers from high blood pressure and there are inadequate health care facilities.

Rope and Construction: The inner bark of the sea hibiscus (Hibiscus tiliaceus), also called ‘hau’, is used in Polynesia for making rope, and the wood for making canoe floats. The ropes on the missionary ship Messenger of Peace were made of fibers from hibiscus trees.

Paper

One species of Hibiscus, known as kenaf (Hibiscus cannabinus), is extensively used in paper-making

-Promise I.O