HEALTH / NURITIONAL BENEFITS OF ROSELLE (ZOBO) PLANT

INTRODUCTION

Medicinal plants are stockroom of phytochemical constituents used for the treatment of various ailments from the ancient era. As the world evolves day by day, the need to understand the chemistry of life forms and how they affect the traditional natural substance have become the focus of the day.The search for new therapeutic remedies from natural sources is an ongoing process. Roselle (Hibiscus sabdariffa) is a popular West African plant taken for its unique flavor. It gets its traditional Nigerian name Zobo from the typical Hausa dialect in Nigeria, Zoborodoa (Aliyu, L. 2000). It is gotten from the Roselle Plant.

Furthermore, the alarming rate of the growth and development of this life forms as well as diseases and illnesses has made it necessary for experiments to be carried out. This seminar work shows the traditional African Roselle (Zobo) plant (Hibiscus sabdariffa), its possible nutritional benefits as well as its nutritional contents.

OVER VIEW OF ROSELLE (ZOBO) PLANT

Roselle (Hibiscus sabdariffa) is a species of Hibiscus probably native to West Africa, used for the production of bast fibre and as an infusion. It is an annual or perennial herb or woody-based subshrub, growing to 2-2.5m (7-8ft)    tall. The leaves are deeply three- to five-lobed, 8-15cm (3-6 in) long, arranged alternately on the stems. The flowers are 8-10cm (3-4in ) in diameter, white to pale yellow with a dark red spot at the base of each petal, and have a stout fleshy calyx at the base, 1-2cm (0.39-0.79 in) wide, enlarging to 3-3.5 cm (1.2-1.4 in), fleshy and bright red as the fruit matures. They take about six months to mature.

1.2       USES

The plant is primarily cultivated for the production of bast fibre from the stem. The fibre may be used as a substitute for jute in making burlap. Hibiscus, specifically roselle, has been used in folk medicine as a diuretic and mild laxative.

The red calyces of the plant are increasingly exported to the United States and Europe, particularly Germany, where they are used as food colourings. It can be found in markets (as flowers or syrup) in places, such as France, Thailand, Tanzania Nigeria etc (Peter, K.V. 2007) The green leaves are used like a spicy version of spinach. They give flavour to the fish and rice dishes (Peter, K.V. 2007) In Burma their green leaves are the main ingredient in chin baung kyaw curry. Brazilians attribute stomachic, emollient, and resolutive properties to the bitter roots.

Zobo Drink, one of the many nutritional drinks produced from the Roselle plant, is found in West Africa. Although several recipes for zobo drink preparation exist, the beverage is generally produced by steaming flower petals of the plant in hot water, additional flavorings and ginger are sometimes added to improve taste and nutritional content. There is widespread consumption of Zobo across Nigeria especially during festivities owing to perceived nutritional benefits. A study published in The American Journal of food technology noted the three varieties of Habiscus Sandarifa used in producing Zobo each had their own specific nutritional value.

NURITIONAL BENEFITS OF ROSELLE (ZOBO) PLANT

 A study published in The American Journal of food technology noted the three varieties of Habiscus Sandarifa used in producing Zobo each had their own specific nutritional value. The Health benefits of Zobo consumption are;

  ·    Zobo and Hypertension (Anti-Hypertensive Property)

Zobo exert its anti-hypertensive effect as a result of its ability to reduce blood cholesterol level. This it does by reducing the amount of plaque which accumulate and narrow blood vessels leading to higher blood pressure and atherosclerosis. Its consumption leads to the reduction in blood pressure of around 7.5/3.5 units (systolic/diastolic) (Serban, C. et al, 2015).

Experiments in animals have shown aqueous and methanol extracts of the plant calyces have hypertensive actions (Odigle, P. et al. 2003). Suggested mechanisms of action include inhibition of angiotensin I converting enzyme, partial cholinergic and/or histaminic mechanisms, (Ali, B.H. 2005) vasodilation, (Ajay, M. et al. 2007) and natriuric effects (Mojiminiyi, F.B. et al. 2007). A number of small clinical trials evaluated the effect of aqueous calyx extracts on blood pressure.

A dose-dependent decrease in systolic and diastolic blood pressure has been demonstrated for aqueous preparations of the hibiscus calyx comparable in effect to that of captopril and lisinopril. A natriuric effect was also observed in these studies (Harrere-Arellano, A et al. 2007). In an earlier trial, patients with essential, but untreated, hypertension demonstrated a decrease in blood pressure with sour tea therapy. Their hypertensive state returned on cessation of therapy (Haji, F.M et al. 1999).

·         Zobo and Cancer (Anti-cancer Properties)

Zobo is a very rich source of vitamin C a powerful anti-oxidant which plays a significant role in the growth and repair of all body tissues (Pau, L.T et al. 2002). It also plays a critical role in the absorption of iron, wound healing and immune system. According to a study published in the international journals of biomedical science, zobo has a rich content of anthocyannins which has several therapeutic properties such as, hepatoprotective and anti-inflammatory, anti-cancer and chemoprotective properties. Studies in rats have evaluated effects against liver, oral, colon, bladder, and stomach cancers. In vitro experiments have shown apoptotic activity against human leukemia (Ali, B.H. et al, 2005).

•  Zobo and Diabetes

Zobo can be very helpful in the management of diabetes especially in Africa where the leaves are in abundant supply. A comprehensive study conducted in the Department of Biochemistry of the Ahamadu Bello University and published in The African Journal of Pharmacognosy and Phytotherapy on the beneficial effects of extracts of Zobo leaves (Hibiscus sabdariffa) in diabetic rats reported that, zobo extract significantly reduce the level of thiobarbituric acid reactive substance (TBARS) and effected a considerable increase in the level of packed cell volume (PCV) when compared with diabetic control group (Public Health, 2018).

• Zobo and Kidney (Kidney Protecting Properties)

The accumulation of the uric acid and oxalic acid in the kidney can lead to the formation of kidneys stones and its attendant health implications. A phytochemical, pharmacological and toxicological analysis of the plant showed that the consumption of zobo results in a significant decrease in the concentrations of creatinine, uric acid, citrate, tartrate, calcium, sodium, potassium and phosphate in the urine and improved kidney function (Public Health, 2018).

Studies in rats suggest a uricosuric effect of the calyx extract (Ali, B.H. 2005). Conflicting clinical data exist regarding the effect of hibiscus extracts on the excretion of uric acid (Prasongwatana, V et al. 2008). The study parameters vary with respect to dose, preparation used, and study population, making conclusions difficult. Increased urinary sodium excretion has been demonstrated in trials evaluating hypotensive effects of hibiscus extracts.

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•      Zobo and Weight gain

There is no conclusive evidence to show the usefulness of zobo drink in any program geared towards losing and gaining weight. A research published in the International Journal of Biomedical Science actually reported that the drink can be useful in regaining loss weight. It is important to note that the quantity of sugar or other sweetening agents added to the drink can promote weight gain.

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•        Zobo and blood formation

This is one question that many have been asking, Zobo has been scientifically proven to help in the fight against anemia. It has been shown to increase blood packed cell volume or (PCV) which refers to the volume occupied by the red cells when a sample of anti-coagulated blood is centrifuged. PCV is very useful in the in the detection of the presence or absence of anemia or polycythemia. It is also used in the estimation of mean cell volume and mean corpuscular hemoglobin concentration. A study published in The African Journal of Biochemistry reported that, zobo extract led to increases in blood glutathione (GSH), red blood cell counts (RBC), white blood cell counts (WBC), packed cell volume (PCV) and hemoglobin (Hb) and concluded that H. sabdariffa or Zobo protects the blood against 2, 4-DNPH lipoperoxidative and hemolytic effects. A similar study conducted by Department of Biochemistry of the Ahamadu Bello University and published in The African Journal of Pharmacognosy and Phytotherapy reported that, zobo extract can significantly effect a considerable increase in the level of blood packed cell volume (PCV).

• Zobo and Cholesterol level

In vitro experiments attribute lipid-lowering action to inhibition of low-density lipoprotein (LDL) oxidation (Ali, B.H. 2005). Studies in hyperlipidemic mice, rats, and rabbits have evaluated the effects of dried calyx extracts on the lipid profile. Although not consistently, the experiments largely demonstrate decreases in serum cholesterol, triglycerides, and LDL, with no effect on high-density lipoprotein (HDL) (Alarcon-Aguilar, F.J et al. 2007).

Additional effects observed include a hypoglycemic effect (Farombi, EO and Ige, OO. 2007) and antiatherosclerotic (histological) action (Chen, C.C et al. 2003).

SIDE EFFECTS OF ROSELLE (ZOBO) PLANT

·         Zobo and Babies / Pregnant women

Several studies have shown that the consumption of zobo during pregnancy or lactation is controversial. A study published in The African journal of alternative and complementary medicine concluded that the consumption of zobo drink during pregnancy increases the possibility of giving birth to babies with low birth weight (LBW). Possibly through the gluconeogenic activities of the elevated serum glutamate pyruvate transaminase (SGPT). This is one of the major controversies of zobo consumption during pregnancy and lactation.

  

·         Zobo and Breast Feeding

Results from a study which evaluated the effect of zobo drink during breast feeding or lactation showed that, consumption of zobo during lactation decreased maternal food and fluid intake, delays the onset of puberty in the female offspring and increased postnatal weight gain.

OTHER EFFECTS OF ROSELLE (ZOBO) PLANT

Aqueous hibiscus extracts have shown inhibitory effects on the contractility of various muscle tissues, including uterine (Fouda, A.M et al. 2007). In other experiments, extracts have demonstrated a mild cathartic activity in rats (Haruna, A.K. 1997) in the absence of increased peristalsis, as well as stimulatory effects in frogs' abdominal/rectal tissues (Ali, B.H. 2005).

Roselle tea extract exhibited high inhibition against porcine pancreatic alpha-amylase. Proposed uses for this inhibition include decreased glucose absorption and inhibition of HIV replication (Hansawasdi, C et al. 2000). Protective effects of the plant extracts on induced testicular and hepatic toxicity have been demonstrated in animals and are attributed to antioxidant action (Amin, A and Hamza, AA. 2006).

BACTERIOLOGICAL CONTERMINATION OF ROSELLE (ZOBO) DRINK

There is increase in the demand for zobo drinks due to its low prices, nutritional and medicinal properties (Oboh, G. and Elusiyan, C.A. 2004). The greatest limitations for large-scale production of zobo drinks is the rapid deterioration of the drink. Its shell-life is approximately twenty-four hours following production if not refrigerated (Osueke, J.C and Ehirim, F.N. 2004. Microorganisms associated with the dried calyx and the processing for the production of zobo drinks and other factors may contribute to its spoilage.

Apart from the fact that most chemical preservatives may have adverse effect on humans, they are expensive and usually not affordable by the local people that produce this zobo drink. The total viable counts was 2.79 log10 cfu mL-1 and total coliforms was 2.62 log10 cfu mL-1.

Bacteria isolated from zobo drink samples included Staphylococcus aureus, Bacillus subtilis, Lactobacillus sp. Escherichia coli, Pseudomonas aeruginosa, Enterobacter aerogenes, Klebsiella sp. The isolates in decreasing order of occurrence were Staphylococcus aureus (45%), Escherichia coli (40%), Lactobacillus sp. (37%), Enterobacter aerogenes (32%), Pseudomonas aeruginosa (30%), Klebsiella sp. (26%) and Bacillus subtilis (23%) (Amusa, O.A et al, 2005).

The total coliforms and total viable counts generally decreased in values following treatment of zobo drink samples with lime juice. Lime juice can be used to prolong the shelf-life of zobo drinks. There is the need for alternative source of preservation that is natural, cheap or affordable and readily available and safe.

The occurrence of the different types of bacteria in zobo drinks is of public health importance. The result obtained indicated that isolation of Staphylococcus aureus from zobo drinks occurred frequently followed by Escherichia coli and other bacteria. The presence of these bacteria indicated possible contamination of the drink. Staphylococcus aureus in zobo drink could possibly be through the processing methods which usually involved the use of hands since the organism is a common flora of the skin. The organism is responsible for staphylococcal food poisoning (Hobbs, B.C and Robert, D. 1993) Generally Escherichia coli is an indicator of water pollution and therefore, the presence of the organism in zobo drink is probably related to the sources or quality of water used for processing. In addition Escherichia coli isolated from water may have some health implications (Nwachukwu, E. and Otokunefor, T.V. 2002).

Moreover additives which were incorporated into the zobo drinks after extraction may be source of contamination. Furthermore, packaging materials which probably were not properly sterilized as well as containers and soil particles or the environment can serve as a source of additional microbial contamination of the zobo drinks (Frazier, W.C and Westhoff, D.C. 1995).

TREATMENT OF ROSELLE (ZOBO) DRINK WITH LIME JUICE

Studies reveals a steady decrease in the number of bacteria in zobo drink samples following treatment with lime juice. The effect of lime juice concentrations on the bacterial quality of zobo drinks prolongs the shell-life of zobo drinks. Since the zobo drinks deteriorate rapidly, may be due to microbial activities, especially when not refrigerated, the major problem is therefore how to preserve the drink. The presence of these bacteria in zobo drinks is therefore no longer in doubt but studies must be pursued towards reducing the bacterial load. This may be explained by the microbial quality of ingredients used and personal hygiene.

Zobo Drink Served With Lime.

The treatment of the zobo drink samples with different concentrations of lime juice suggest that the bacterial load of the drink reduces considerably thereby prolonging the shelf-life of the drink. The possible explanation for the reduction of the bacterial load in zobo drinks following addition of lime juice is the acidic nature of the lime juice. According to Jay, J.M. (1996) the excellent keeping quality of fruits and soft drinks is due to low pH. This is because low pH tend to inhibit bacterial growth.

Therefore the addition of lime juice should be encouraged since this study has reviewed that lime juice can inhibit bacterial growth in zobo drinks (Nwachukwu, E. et al. 2007). Moreover lime fruits are not hazardous and hence safe for human consumption. Fasoyiro, S.B et al. (2005) determined the effect of three storage conditions and reported that the microbial load of samples at ambient and refrigeration increased with time. How ever since few organisms such as fungi can survive acidic medium further studies should be carried out to test the effect of lime juice on fungi. There is also the need to investigate other natural preservatives especially of plant origin on the microbial quality of drinks.

The result of the effect of lime on quality of zobo drinks is a finding that will be useful. Since zobo drinks is easy to produce at home, packaged in polyethylene containers and sold as source of income for most families, lime juice as preservative is recommended so as to prolong the shelf life.

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