Introduction

Diabetes Overview

Diabetes is a chronic medical condition of hyperglycaemia where blood  sugar levels are elevated due to the body's inability to produce or effectively  use insulin. In a human’s healthy body, their pancreas, an organ located  behind the liver and stomach, secretes enzyme called insulin that controls  the blood glucose levels in the body. Hence, diabetic people either has the  inability to produce or recognize the insulin which can be divided into two  types: type 1 and type 2.  

Type 1 diabetes is an autoimmune condition where the body's immune  system attacks and destroys insulin-producing beta cells in the pancreas,  leading to little or no insulin production. While type 2 diabetes is a condition  where the body's cells do not use insulin properly, known as insulin  resistance. Initially, the pancreas makes more insulin to compensate, but  over time it can't keep up, resulting in elevated blood glucose levels.  

Diabetes can significantly impact various body systems over time, leading  to both macrovascular and microvascular complications. Macrovascular complications include damage to large blood vessels, increasing the risk of  cardiovascular diseases such as heart attack and stroke. Microvascular  complications affect small blood vessels, leading to issues in the eyes  (retinopathy), kidneys (nephropathy), and nerves (neuropathy). This can  result in vision problems, kidney failure, and nerve damage, particularly in  the extremities, which may cause foot ulcers and infections, potentially leading to amputations.

Common Anti-Diabetic Treatments

Diabetes is responsible for 6.7 millions deaths of the world in 2021.  While 44% of people living with diabetes are undiagnosed, 90% of  these problems are found in middle and low-income countries such  as Indonesia. Hence, not only do these people identify themselves to  struggle with the disease, it is also a battle of cost, as a lot of them who are in lower economical statuses cannot afford the costly  treatments commonly used.  

A drug commonly sold in the market for type 2 diabetes is also  known as Acarbose, which is also used to treat the positive  hyperglycemic group in this investigation. Acarbose possess alpha  glucosidase inhibiting properties that inhibits the active absorption of  glucose. This lowers down the blood glucose level from the  hyperglycemic stage which has been proved to treat adults with type  2 diabetes mellitus.  

However, by investigating further the anti-diabetic properties of the Castanopsis Tunggurut plant, we hope to find a much more  cost-efficient treatment as it can be found naturally and hopefully it  can be more accessible to those suffering from type 2 diabetes.

Castanopsis tunggurut

The Castanopsis Tunggurut Blume A. DC is a plant that currently can only be found in Indonesia and Malaysia. Despite it being categorized as one of the endangered species, Indonesia is  making efforts in harvesting and conserving them, one of which is  placed in the Cibodas Biosphere Reserve. C. Tunggurrut is  currently observed closely but as of now, there has been no  findings pertaining to this plant. Although, a recent investigation  has been made by a former ASA student, in which an antidiabetic  activity potential is found via in vitro, which is proven to inhibit  alpha-glucosidase. Hence, to confirm these findings further, an investigation of C. Tunggurut via in vivo or through the administering through animals is proceeded.

Sample Preparation & Extraction Using Ethanol 70%

A total of 235 g of C. Tunggurut leaves undergoes a  maceration process, where the leaves are added to 1.175L  of ethanol 70% until the simplicia (raw natural ingredient  used for medicine) submerges by occasionally stirring and  allowing it to settle. The ethanol attracts the active  ingredients that consist of the same polar in the  C.Tunggurrut extract. This attraction causes the ethanol to  appear brown and later on is filtered out. The remaining  substance from the filtration is left to evaporate which in  turn results to leave a thickened gel or jam-like substance  which is a result of the C. Tunggurt extraction that is  obtained. This is then evaporated with rotary vacuum  evaporator and dried with oven at 40°C. The dry substance  is the C. Tunggurrut extraction that is ready to use.

Animal Preparation

In this investigation, thirty male Wistar rats aged 8-12 weeks and weighing 100-150 g  are being used as the subject of the testing of the C. Tunggurrut. These rats were  maintained in polyethylene cages, inside a well-ventilated laboratory, with a controlled  temperature of 25 ± 2oC. Other controlled conditions include the constant 12:12 hour  light-dark cycle and the feeding of standard animal food and water available ad libitum.  Prior to this study, the rats were allowed to acclimatize to the laboratory for seven days  which is a protocol that has been approved by The Research Ethics Committee of  Universitas Padjadjaran Bandung, Indonesia. Under The Research Ethics Committee,  this experiment is  registered with the number of 438/UN6.KEP/EC/2024.

Hyperglycemic Induction

Hyperglycemic IC induction is the process of after one week of adaptive feeding. The animals were randomly divided into 2 groups: 

1. The normal group (n=5) > fed a standard food

2. The hyperglycemic group (n=25) > fed a high-fructose fat (40% fructose, 20% lard and 5% egg yolks)

Treatment

Four rats were randomly selected from the normal group to continuously be treated ‘normally’ meaning that they receive standard food. While the  rest of the  hyperglycemic groups were divided into five other groups such as the following:  

• Group 1: The normal group is treated normally without any additional treatments other than receiving standard rat food.

• Group 2 (-): Hyperglycemic rats receive negative treatment, indicating that they are still kept diabetic by the oral administration of CMC Na.  

• Group 3 (+): Hyperglycemic rats receive positive treatment, where it aims to lower their blood glucose levels by orally administering acarbose dose  of 5 mg/KgBW as a current therapy used for type 2 diabetes.  

• Group 4: Hyperglycemic rats received extract of Castanopsis Argentea dose  75 mg/kgBW orally  

• Group 5: Hyperglycemic rats received extract of Castanopsis Argentea dose  150 mg/kgBW orally  

• Group 6: Hyperglycemic rats received extract of Castanopsis Argentea dose  300 mg/kgBW orally  

All rats were treated by oral administration for 2 weeks. During this period, after fasting overnight, fasting blood glucose and body weight were  measured simultaneously at days 3, 5, 7, 9,12 and 14. Fasting blood glucose were carried out using whole blood from rat tail tips and a hand held  glucometer (Nesco, Kernel Int'l Corp, Taiwan.

Result 

Result can be seen in the image section.

Conclusion

Based on the data obtained. a high-fat and fructose diet can increase the blood glucose levels of test rats. However. this diet needs to be  reassessed as the increase in blood glucose levels takes a considerable amount of time and the resulting blood glucose levels are unstable  and not very high. The experiment results also show that administering Castanopsis Tunggurut ethanol extract at doses of 75, 150, and 300  mg/Kg BW all have the potential to lower blood sugar levels in the test animal model. Of the three doses. the 150 mg/Kg BW dose of  Castanopsis Tunggurut ethanol extract is the most effective in reducing blood glucose levels.