Clinical & Medical Biochemistry

Ethanol Leaf Extract of Anacardium occidentale Ameliorates Alloxan Induced Changes on Blood Glucose Level and Lipid Profile of Wistar Rats

OD Oshan Abu^1*, KE Imafidon¹ and O Obayuwana^{2 1}Department of Biochemistry, University of Benin, Edo State, Nigeria
²Department of Science Laboratory Technology, University of Benin, Edo State, Nigeria
^*Correspondence: OD Oshan Abu, Department of Biochemistry, University of Benin, Edo State, Nigeria, Tel: 2347086427636, Email:

Received: 22-Sep-2020, Manuscript No. CMBO-20-6561; Editor assigned: 26-Sep-2020, Pre QC No. CMBO-20-6561(PQ); Reviewed: 10-Oct-2020, QC No. CMBO-20-6561; Revised: 02-Jan-2023, Manuscript No. CMBO-20-6561(R); Published: 30-Jan-2023, DOI: 10.35841/2471-2663.22.9.142

Introduction

It is estimated that by the year 2030 the number of persons with Diabetes Mellitus (DM) would increase to 366 million. Diabetes Mellitus (DM) is a condition primarily defined by the level of hyperglycemia giving rise to risk of microvascular damage (retinopathy, nephropathy and neuropathy). It is associated with reduced life expectancy, significant morbidity due to specific diabetes related microvascular complications, increased risk of macrovascular complications (ischemic heart disease, stroke and peripheral vascular disease), as well as diminished quality of life [1]. If blood glucose level remains high (hyperglycemia) over a long period of time, it results in long term damage to organs such as kidney, liver, eye, nerves, heart and blood vessels. Type-2 Diabetes Mellitus (T2DM) often exhibits an atherogenic dyslipidemia characterized by elevation of TG, reduction of HDL-C, as well as residual cardiovascular risk. Insulin affects many aspects of mammalian lipid metabolism. Early interventions aimed at normalizing circulating lipids reduce cardiovascular complications and mortality. Many of the drugs currently used for the treatment of DM produce adverse effects. Sulfonylureas stimulate pancreatic islet cells to secrete insulin, while metformin slows down hepatic glucose production. All these therapies have limited effectiveness, thereby necessitating the search for novel plant based compounds that can effectively reduce blood glucose [2].

The antidiabetic effect of plant derived compounds is due to their capacity to alter carbohydrate digestion/absorption, stimulate beta cell function, mimic insulin action and mop up Reactive Oxygen Species (ROS). Anacardium occidentale (cashew tree) is a tropical plant indigenous to Brazil, Portugal, India, Southeast Asia and Africa. Extracts of the plant have been reported to possess hypoglycemic effect [3]. The young and tender leaves of A. occidentale are consumed raw or sometimes blanched to reduce the stringent taste. In traditional medicine, the leaves are used for the treatment of dysentery, diarrhea, piles, toothache, sore gums, rheumatism and hypertension. This study investigated the effect of aqueous leaf extract of A. occidentale on blood glucose level and lipid profile of diabetic rats [4].

Materials and Methods

Chemicals and reagents

All reagents used were of analytical grade. Lipid profile, ALT and ALP assay kits were products of Randox laboratories limited (UK). All other chemicals were obtained from British Drug House (BDH) (England), Merck (Germany) and Sigma-Aldrich (USA).

Plant sample collection

The plant leaves were obtained from dentistry quarters, university of Benin, Benin city and authenticated at the herbarium of the department of plant biology and biotechnology, university of Benin, Benin city, Nigeria [5].

Plant preparation and extraction

The leaves were washed and shade dried at room temperature for a period of two weeks and pulverized using mechanical blender. Aqueous extract of the leaves was obtained using cold maceration method [6].

Experimental rats

Adult male Wistar rats (n=30) weighing 150 g-200 g (mean weight=175 g ± 25 g) were obtained from the department of anatomy, university of Benin, Benin city. The rats were housed in metal cages under standard laboratory conditions: Average temperature of 25°C, 55% 65% humidity and 12 h light/12 h dark cycles. They were allowed access to rat feed (pelletized growers mash) and clean drinking water [7]. Prior to commencement of the study, the rats were acclimatized to the laboratory environment for one week. The study protocol was approved by the faculty of life sciences ethical committee on animal use.

Experimental design

The rats were randomly assigned to 6 groups (5 rats/group): Normal control, diabetic control and DMSO, metformin, extract and treatment groups. Diabetes Mellitus (DM) was induced via intraperitoneal injection of freshly prepared alloxan monohydrate solution at a dose of 120 mg/kg bwt. Rats in normal control, DMSO and extract groups were not induced [8]. Rats in treatment and extract groups received aqueous leaf extract of A. Occidentale at a dose of 100 mg/kg bwt orally for 4 days. Metformin served as standard drug and was administered orally at a dose of 50 mg/kg bwt. Dimethylsulfoxide (DMSO) was used to solubilize the extract.

Blood sample collection and plasma preparation

At the end of the treatment period peripheral venous blood was drawn from retro orbital plexus of each rat after mild anesthesia and centrifuged at 3000 rpm for 10 min to obtain plasma which was used for biochemical analysis [9,10].

Determination of blood glucose level

The rats were fasted overnight and their FBG level was measured with a glucometer (Accu-Chek).

Measurement of activities of ALT and ALP

Alanine Aminotransferase (ALT) and ALP activities were assayed using their respective commercial kits [11].

Determination of lipid profile

Lipid profile parameters were determined using randox kits. Only LDL-C and VLDL-C were determined via calculation using the frieldwald equation as shown below:

VLDL-C=TG/5

LDL-C=TC-(TG/5)-HDL-C

Statistical analysis

Data are expressed as mean ± SEM. Statistical analysis was performed using SPSS (21.0). Groups were compared using student t test [12]. Statistical significance was assumed at p<0.05.

Results

Effect of aqueous extract of A. occidentale leaves on body and organ weights of diabetic rats: Treatment of diabetic rats with aqueous extract of A. occidentale leaves significantly reduced their body weights, but there were no significant differences in the relative weights of kidney, pancreas and liver among the groups (Tables 1 and 2) [13].

Table 1: Body and organ weights of diabetic rats.

Table 2: Percentage change in body weight and relative organ weights of diabetic rats.

Effect of aqueous extract of A. occidentale leaves on FBG of diabetic rats: As shown in Table 3, treatment of diabetic rats with aqueous extract of A. Occidentale leaves led to significant and time dependent reductions in their FBG levels (p<0.05) [14].

Table 3: Fasting blood glucose of diabetic rats.

Effect of aqueous extract of A. occidentale leaves on lipid profile of diabetic rats: Treatment of diabetic rats with aqueous extract of A. occidentale leaves significantly reduced the circulating levels of TG, TC, VLDL-C and LDL-C, but it significantly increased HDL-C level (p<0.05). These results are shown in Table 4 [15,16].

Table 4: Lipid profile of diabetic rats.

Effect of aqueous extract of A. occidentale leaves on activities of liver enzymes: Aqueous leaf extract of A. occidentale significantly reduced the activities of ALT and ALP in serum of diabetic rats (p<0.05) (Table 5).

Table 5: Effect of aqueous extract of A. occidentale leaves on activities of liver enzymes.

Discussion

Diabetes Mellitus (DM) is a group of metabolic disorders characterized by hyperglycemia resulting from defects in insulin secretion, insulin action, or both. The chronic hyperglycemia of diabetes is associated with long term damage, dysfunction, and failure of different organs, especially the eyes, kidneys, nerves, heart, and blood vessels [17,18].

Several pathogenic processes are involved in the development of DM. These range from autoimmune destruction of the pancreatic beta cells with consequent insulin deficiency to abnormalities that result in resistance to insulin action. The basis of the abnormalities in carbohydrate, fat, and protein metabolism in DM is deficient action of insulin on target tissues. Deficient insulin action results from inadequate insulin secretion and/or diminished tissue responses to insulin at one or more points in the complex pathways of hormone action.

Impairment of insulin secretion and defects in insulin action frequently coexist in the same patient, and it is often unclear which abnormality, if either alone, is the primary cause of the hyperglycemia [19]. As a tropical plant A. occidentale is indigenous to Brazil, Portugal, India, Southeast Asia and Africa. Extracts of Anacardium occidentale (cashew tree) are used in folk medicine for the treatment of DM, diarrhea, skin diseases, arthritis, fever, aches and pains. This study investigated the effect of aqueous leaf extract of A. occidentale on blood glucose level and lipid profile of diabetic rats [20].

Alloxan ((5,5-dihydroxyl pyrimidine-2,4,6-trione), a carcinogen and cytotoxic glucose analog, is one of the common diabetogenic agents often used to assess the antidiabetic potential of both pure compounds and plant extracts in studies involving DM. Among the known diabetogenic agents which include dithizone, monosodium glutamate, gold thioglucose, high fructose load, high glucose load and anti insulin serum; alloxan and Streptozotocin (STZ) are the most widely used in diabetes studies. Alloxan is administered as single or multiple doses, via different routes (intraperitoneal, intravenous and subcutaneous); with single intraperitoneal administration apparently the most employed mode [21]. In DM, the levels of free fatty acids are usually elevated. The circulating free fatty acids have deleterious effect on endothelial functions through various pathways and mechanisms which include free radical production, protein kinase c activation and increase in severity of dyslipidemia. Oxidative stress, caused by an increase in free radical production, is strongly linked to insulin resistance and progression of DM. With an increase in oxidative stress, coupled with increase in free fatty acids and blood glucose level, insulin secretion and activity are adversely affected. The liver function markers (ALT and ALP) were also assessed in this study to ascertain the effect of drug treatment in diabetic rats.

Conclusion

The results obtained in this study suggest that aqueous extract of Anacardium occidentale leaves mitigates diabetogenic action of alloxan in Wistar rats. It has been reported that alloxan has a non specific action on the destruction of vasculature of other organs, besides pancreas. The accumulation of exogenous insulin in the blood after the destruction of pancreatic cells may be due to impaired renal and hepatic functions. The results of this study showed that aqueous extract of A. occidentale leaves significantly mitigated alloxan induced metabolic derangement in rats, and are in agreement with those of previous reports.

References

1. Abbott RD, Brand FN, Kannel WB. Epidemiology of some peripheral arterial findings in diabetic men and women: experiences from the framingham study. Am J Med. 1990;88(4):376-381.

   [Crossref][Googlescholar][Indexed]                    

2. Barcelo A, Rajpathak S. Incidence and prevalence of diabetes mellitus in the Americas. Rev Panam Salud Publica. 2001;10(5):300-308.

   [Crossref][Googlescholar][Indexed]

3. Funke I, Melzig MF. Traditionally used plants in diabetes therapy: Phytotherapeutics as inhibitors of alpha amylase activity. Rev bras farmacogn. 2006;16:1-5.

   [Crossref][Googlescholar]

4. Adetuyibi A. Diabetes in the Nigerian African. Review of long term complications. Trop Med Int Health. 1976;28(3):155-159.

   [Googlescholar][Indexed]            

5. Pari L, Saravanan R. Antidiabetic effect of diasulin, a herbal drug, on blood glucose, plasma insulin and hepatic enzymes of glucose metabolism in hyperglycaemic rats. Diabetes Obes Metab. 2004;6(4):286-292.

   [Crossref][Googlescholar][Indexed]                        

6. Haffner SM, Lehto S, Ronnemaa T, Pyorala K, Laakso M. Mortality from coronary heart disease in subjects with type 2 diabetes and in nondiabetic subjects with and without prior myocardial infarction. N Engl J Med. 1998;339(4):229-234.

   [Crossref][Googlescholar][Indexed]                  

7. Windler E. What is the consequence of an abnormal lipid profile in patients with type 2 diabetes or the metabolic syndrome?. Atheroscler Suppl. 2005;6(3):11-14.

   [Crossref][Googlescholar][Indexed]               

8. Tiwari AK, Rao JM. Diabetes mellitus and multiple therapeutic approaches of phytochemicals: Present status and future prospects. Current science. 2002;10:30-38. [Crossref][Googlescholar]               
9. Braga A, Medeiros TP, Araujo BV. Investigation of the antihyperglycemic activity of Passiflora edulis Sims, Passifloraceae, bark flour in alloxan-induced diabetic rats. Rev Bras Farmacogn. 2010;20:186-191.

   [Googlescholar][Indexed]            

10. Nugroho AE, Malik A, Pramono S. Total phenolic and flavonoid contents, and in vitro antihypertension activity of purified extract of Indonesian cashew leaves (Anacardium occidentale L.). Int Food Res J. 2013;20(1).
11. Schmourlo G, Mendonca-Filho RR, Alviano CS, Costa SS. Screening of antifungal agents using ethanol precipitation and bioautography of medicinal and food plants. J Ethnopharmacol. 2005;96(3):563-568.

    [Crossref][Googlescholar][Indexed]                 

12. Souto WM, Mourao JS, Barboza RR, Alves RR. Parallels between zootherapeutic practices in ethnoveterinary and human complementary medicine in Northeastern Brazil. J Ethnopharmacol. 2011;134(3):753-767.

    [Crossref][Googlescholar][Indexed]                    

13. Coe FG, Anderson GJ. Ethnobotany of the Garifuna of Eastern Nicaragua. Econ Bot. 1996 1:71-107.

    [Googlescholar]                    

14. Lenzen S. The mechanisms of alloxan and streptozotocin induced diabetes. Diabetologia. 2008;51(2):216-226.

    [Crossref][Googlescholar][Indexed]

15. Federiuk IF, Casey HM, Quinn MJ, Wood MD, Ward KW. Induction of type-1 diabetes mellitus in laboratory rats by use of alloxan: route of administration, pitfalls, and insulin treatment. Compare Med. 2004;54(3):252-257.

    [Googlescholar]

16. Inoguchi T, Li P, Umeda F, Yu HY, Kakimoto M, Imamura M, et al. High glucose level and free fatty acid stimulate reactive oxygen species production through protein kinase C-dependent activation of NAD (P) H oxidase in cultured vascular cells. Diabetes. 2000;49(11):1939-1945.

    [Crossref][Googlescholar][Indexed]                        

17. Rahimi R, Nikfar S, Larijani B, Abdollahi M. A review on the role of antioxidants in the management of diabetes and its complications. Biomed Pharmacother. 2005;59(7):365-373.

    [Crossref][Googlescholar][Indexed]

18. Qinna NA, Badwan AA. Impact of streptozotocin on altering normal glucose homeostasis during insulin testing in diabetic rats compared to normoglycemic rats. Drug Des Devel Ther. 2015;9:2515-2516.

    [Crossref][Googlescholar][Indexed]               

19. Kamtchouing P, Sokeng SD, Moundipa PF, Watcho P, Jatsa HB, Lontsi D. et al. Protective role of Anacardium occidentale extract against streptozotocin-induced diabetes in rats. J Ethnopharmacol. 1998;62(2):95-99.

    [Crossref][Googlescholar][Indexed]                 

20. Jaiswal YS, Tatke PA, Gabhe SY, Vaidya AB. Antidiabetic activity of extracts of Anacardium occidentale Linn. leaves on n-streptozotocin diabetic rats. J Tradit Complement Med. 2017;7(4):421-427.

    [Crossref][Googlescholar][Indexed]                    

21. Beejmohun V, Mignon C, Mazollier A, Peytavy-Izard M, Pallet D, Dornier M, et al. Cashew apple extract inhibition of fat storage and insulin resistance in the diet induced obesity mouse model. J Nutr Sci. 2015;4:37-38.

    [Crossref][Googlescholar][Indexed]