Jannatara Khatun, Professor, Department of Animal Science and Nutrition, CVASU, for her competent supervision, scientific and passionate excellent guidance, valuable suggestions and constructive criticism throughout the period of my dissertation and in the preparation of this dissertation. I also express my special gratitude and sincere gratitude to my beloved co-supervisor Mohammad Mozibul Haque, Assistant Professor, Department of Applied Food Sciences and Nutrition, CVASU, for his guiding support and sincere cooperation during my research work. Azizul Islam, Professor, Department of Physiology, Biochemistry and Pharmacology, for their valuable suggestions, inspirations and collaborations.
I also express my sincere thanks to all my respected teachers in the Faculty of Food Science and Technology, CVASU, for their support in completing my research work smoothly. I also express my gratitude to all the staff and members of the Department of Applied Food Science and Nutrition, Department of Animal Science and Nutrition, Department of Food Processing and Engineering, and Department of Physiology, Biochemistry and Pharmacology, for their continuous inspiration and friendly cooperation to carry out the research activities precisely to execute. I would like to express my gratitude to the Ministry of Science and Technology, Bangladesh and Advanced Studies and Research, CVASU, for providing funds for this research work.
The in vitro antioxidant activity of mucilage and husk seed powder was determined by DPPH free radical scavenging assay, total phenolic content and total flavonoid content.
Introduction
Okra fruits are generally eaten as vegetables and are also used in the preparation of salads, soups and stews (Gemede et al., 2015). However, recent study revealed that the proximate composition varies in different okra accessions (Gemede et al., 2016). Okra seeds are a good source of protein and oil and rich in linoleic acid, which is essential for human nutrition (Savello et al., 1980; Oyelade et al., 2003).
Okra has been shown to be effective in treating diabetes, digestive problems, colon health, body cholesterol levels and heart health (Gemede et al., 2015). Different parts of the okra plant have also revealed the presence of the total phenolics, total flavonoids and antioxidant properties (Liao et al., 2012). Okra mucilages are generally acidic polysaccharides composed of galacturonic acid, galactose, rhamnose, arabinose and glucose (Woolfe et al., 1977).
Previous research studies also produce the okra slime as a potential pharmaceutical substance (Farooq et al., 2013).
Review of Literature
- Diabetes Mellitus
- Classification
- Etiology of diabetes mellitus
- Pathophysiology and pathogenesis of diabetes
- Epidemiology of diabetes
- Signs and symptoms
- Diagnosis
- Management of diabetes mellitus
- Drug Therapy
- Diet Therapy
- Overview of okra (Abelmoschus esculentus)
- Okra constituents and uses
- Medicinal effects of Okra
- Significance of plant based diet/medicine to improve diabetes mellitus
- Mucilage and Diabetes
- Summary of alloxan-induced diabetes
- Conclusion
The study of different ethnic groups showed that environmental factors play a decisive role in the prevalence of diabetes (LaPorte et al., 1985). A significantly higher incidence of type I diabetes is observed in males compared to females (Bruno et al., 1993). However, during the onset of diabetes there may also be unexplained weight loss (Guariguata et al., 2014).
It also improves glucose uptake in peripheral tissues, mainly muscle (Chehade and Mooradian, 2000; Collier et al., 2006). The name Okra is probably derived from a language group from Niger-Congo (the name for okra in the Twi language is nkuruma) (Yonas et al., 2014). The hydrolysis of okra mucilage yielded rhamnose, galactose, glucose, galacturonic acid and glucuronic acid (Woolfe et al., 1977).
In vivo study of different parts of okra also showed antidiabetic activity (Sabitha et al., 2011). The use of okra is an efficient method to manage the level of cholesterol in the body (Nguyen et al., 2019). This is due to the specific necrosis action of pancreatic beta cells (Dunn et al., 1943).
Materials and Methods
- Study area and Study period
- Layout of experiment
- Plant material/Sample collection
- Extraction of Mucilage
- Peel-Seed powder preparation
- Experimental animals and Diet
- Acute toxicity study
- Induction of Diabetes
- Experimental design
- Oral glucose tolerance test
- Collection of Blood Samples
- Biochemical tests
- Methanolic extraction of PM and PPS
- Antioxidant activity
- Preparation of DPPH solution (100 µm)
- Preparation of standard ascorbic acid solution
- Preparation of sample solution
- Procedure
- Determination of total phenol content
- Preparation of standard gallic acid solution
- Procedure
- Total flavonoid content determination
- Preparation of 1M potassium acetate solution
- Preparation of 10% AlCl 3 solution
- Preparation of standard quercetin solution
- Procedure
- Mineral analysis
- Crude protein determination
- Statistical analysis
It was then heated in a water bath with continuous stirring for 30 min at 60 °C to allow a thorough release of the mucilage into the water. After extracting the mucus, the separated fruits with seeds were taken into a tray. The powder mixture (PPS) was then sieved through a #80 mm sieve and stored in an airtight container until the study was completed.
A total of sixty healthy Swiss albino laboratory mice weighing between 23–27 g were purchased from the animal house of the Department of Pharmacy, Jahangirnagar University, Bangladesh. Mice were maintained in the animal house of the Department of Animal Science and Nutrition, Chattogram Veterinary and Animal Science University (CVASU). During the entire study period, the mice were fed a pellet diet as presented in (Table 3).
Body weight and fasting blood glucose levels of mice were recorded weekly during the experimental period. Calculation of the area under the curve (AUC) was measured according to the following formula (Dong et al., 2014). At the end of the experiment, blood samples were collected by cardiac puncture from animals that were anesthetized (with diethyl ether) overnight.
The DPPH radical scavenging capacity of the test samples was determined by following the method described by (Nariya et al., 2013; Gemede et al., 2018). To prepare a 1 mg/ml stock solution, approximately 10 mg of ascorbic acid was dissolved in 10 ml of distilled water. Then the absorbance of the solution was measured at 517 nm using a UV-Vis spectrophotometer against blank.
To prepare stock solution of 1 mg/ml, approximately 10 mg of gallic acid was dissolved in 10 ml of distilled water. Then 10 ml of 20% sodium carbonate was added to the mixture and left for one hour at room temperature for incubation.
Results
- Yield of dry mucilage
- Toxicity study
- Effect of mucilage and peel-seed on fasting blood glucose level
- Oral Glucose Tolerance Test (OGTT)
- Effects of PPS and PM on body weight of mice
- Food and water consumption of alloxan-induced diabetic mice
- Lipid profile
- Total protein content in blood
- In vitro antioxidant activity
- DPPH free radical scavenging assay
- Total phenol content
- Total flavonoid content
- Mineral contents
- Protein content
The calculation of the AUC (area under the curve) also indicated the significant (P<0.001) decrease of all treatment groups in contrast to the DC group (Figure 9). The average body weight of all mice in different groups was approximately 25 grams at the beginning of the experiment. The weight of normal control mice continued to increase steadily and the diabetic control group consistently lost weight until the end of the experiment, as shown in Figure 10.
However, at the end of the experiment, all treated mice showed a significant (P < 0.001) increase in body weight compared to the diabetic control group (Figure 10). NC mice consumed approximately 4.6 g/day of food, while the rate of consumption in DC was statistically significantly higher (P<0.001) at 11.1 g/day. This study also shows that the mucilage and hulled seed mixture significantly (P<0.001) increased HDL levels and decreased cholesterol, triglyceride and LDL levels in alloxan-induced diabetic mice compared to the diabetic control group ( Table 6 ).
It is also clear that, at the same doses, PPS exerted a superior hypolipidemic effect than that of PM. In the present study, a significantly (P<0.001) reduced total protein was observed in diabetic control rats than normal control rats. However, the total protein level was significantly increased (P<0.001) after administration of both doses of PM and PPS compared to diabetic control rats (Table 6).
Results for the DPPH free radical scavenging activity of methanolic extracts of PM and PPS shown in Figure 13. Thus, compared to ascorbic acid, it is clear that both the powdered mucilage and the husk seed possess antiradical activity. The total phenolic content of the methanol extract of PM and PPS was found to be 68.84 ± 0.3 mg gallic acid equivalent per gram and 65.98 ± 0.3 mg gallic acid equivalent per gram.
Total flavonoid content of the methanolic extract of peel-seed (PPS) mixture was 9.50±1.1 mg Quercetin equivalent/g and for mucilage (PM) the value was 7.90±0.1 mg Quercetin equivalent/g. Powdered husk-seed mixture had significantly (P<0.05) higher amounts of potassium, calcium, magnesium and phosphorus in contrast to powdered mucilage (Table 8).
Discussions
The hypoglycemic effect of PM and PPS showed a proportional relationship with increasing dose, indicating their usefulness in the treatment of diabetes mellitus. The standard drug glibenclamide helps in diabetes management by controlling insulin secretion and insulin action (Luzi and Pozza, 1997). A similar scenario was observed in the current study, where the diabetic control group showed excessive levels of LDL, triglycerides and total cholesterol.
The present study conducted on mice supported this theory by revealing that okra mucilage, husk seed can help in the management of diabetes by controlling the glycemic load in blood and thus helps to lower the hyperlipidemic effect on diabetic mice. Moreover, the total protein level in the treatment group also increased compared to the diabetic group. 50 | P a g e to high protein content present in powdered mucilage and husk seed which was also shown in the present study.
Therefore, this study concludes that both PM and PPS have potential in the treatment of dyslipidemia in diabetic subjects. Previous experiment has reported that consumption of peel and seed powder can lower glucose level as well as cholesterol level in diabetic subjects (Sabitha et al., 2011). This result is also supported by another previous study, which shows higher effectiveness of okra seed than mucilage (Hajian et al., 2016).
It is known that dietary flavonoids and antioxidants play a crucial role in the antidiabetic mechanism in the body (Bajaj and Khan, 2012; Babu et al., 2013). Interestingly, researchers have also revealed that active antioxidants in polysaccharides, such as mucus, can lower blood sugar levels in both normal and drug-induced diabetic patients (Li et al., 2006). Studies have also shown that hydroxycinnamic acid, a derivative of cinnamic acid, can improve glucose hemostasis and insulin resistance, thus helping to prevent diabetes complications (Adisakwattana, 2017).
This is also supported by a study reported by Fan et al., (2014b), where isoquercitrin and quercetin 3-O-gentiobioside were found to be effective in lowering blood glucose levels and improving glucose tolerance in obese mice. caused by high fat content. 51 | P a g e Overall, the findings in this study showed that the mucilage and peel of Abelmoschus esculentus have in vitro antioxidant activity and can improve the blood glucose level and lipid profile of diabetic mice.
Conclusion
Recommendations & future perspectives
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