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European Journal of Applied Sciences – Vol. 11, No. 3

Publication Date: June 25, 2023

DOI:10.14738/aivp.113.14845.

Revelo-Cáceres, D., Oliveras-López, M. J., & López-García de la Serrana, H. (2023). Development of an Infusion for LDL Cholesterol

Based on Avocado Leaves (Persea americana), Guava Leaves (Psidium guajava) and Cinnamon. European Journal of Applied

Sciences, Vol - 11(3). 398-406.

Services for Science and Education – United Kingdom

Development of an Infusion for LDL Cholesterol Based on

Avocado Leaves (Persea americana), Guava Leaves (Psidium

guajava) and Cinnamon

Daniel Revelo-Cáceres

Universidad de Granada, Facultad de Farmacia, Granada-España

María Jesús Oliveras-López

Universidad Pablo de Olavide, Departamento de Biología

Molecular e Ingeniería Bioquímica, Sevilla-España

Herminia López-García de la Serrana

Universidad de Granada, Facultad de Farmacia, Granada-España

ABSTRACT

An infusion based on avocado leaves, guava leaves and cinnamon were developed

as a potential alternative for the treatment of LDL cholesterol. Avocado and guava

leaves were washed, dehydrated and ground. Optimal dehydration length for

avocado leaves was determined using weight loss curves, from which it was decided

to treat leaves for 60 minutes at 40oC. Similarly, optimal dehydration conditions for

guava leaves were achieved in a period of 80 minutes at 45oC. Three infusion

formulations were tested. All formulations contained 1.5 g of guava leaves and 6 g

of cinnamon, alongside 5, 10 and 15 g of dehydrated avocado leaves, respectively. A

sensory analysis was carried out in which raters ranked the infusions in terms of

taste and aroma, Basker's preference test was conducted and purchase intentions

were gaged. Tasters preferred the formulation containing the lowest amount of

dehydrated avocado leaves. 91.67% of tasters indicated that they would buy this

infusion due to its possible functional properties.

Keywords: Infusion, avocado leaves, guava leaves, cinnamon, LDL cholesterol, sensory

analysis.

INTRODUCTION

High levels of cholesterol in the blood have been related to an increased risk of cardiovascular

disease in individuals aged above 40 years [1]. This increase is known as hypercholesterolemia,

which is one of the most common metabolic diseases and results from high LDL (low-density

lipoprotein cholesterol) cholesterol levels [2]. A high level of LDL cholesterol is a risk factor for

the development of atherosclerosis, which can cause cardiovascular problems such as

myocardial infarction and stroke [3]. This has led to the measurement of LDL cholesterol being

considered as an indicator of great importance. Specifically, values <70 mg/dL in the blood

indicate that an individual has a low risk of cardiovascular disease. In contrast, individuals with

LDL values ≥190 mg/dL are classified as high risk, with this risk having to be controlled through

medication [4]. Unfortunately, many of the drugs used to treat this condition can lead to a

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399

Revelo-Cáceres, D., Oliveras-López, M. J., & López-García de la Serrana, H. (2023). Development of an Infusion for LDL Cholesterol Based on Avocado

Leaves (Persea americana), Guava Leaves (Psidium guajava) and Cinnamon. European Journal of Applied Sciences, Vol - 11(3). 398-406.

URL: http://dx.doi.org/10.14738/aivp.113.14845.

higher incidence of diabetes mellitus and myopathy [5]. An example of this can be seen in the

case of statins. Despite being the most used treatment for cholesterol, several investigations

have revealed that they may promote the calcification of the cardiovascular disease coronary

atheroma [6]. Likewise, acute memory loss could be related to the use of drugs to control

cholesterol, due to the modification of the lipid composition of the brain [7]. The biological

compounds of various foods have aroused great interest due to their possible effects on

diseases such as hypercholesterolemia, diabetes, oxidative stress and hypertension [8]. One

such food is avocado, whose pulp is commonly consumed and has a high composition of

monounsaturated fatty acids. However, the peel, seed and leaves of this fruit have several

compounds with functional properties [9]. In rats inoculated with carbon tetrachloride (known

to contribute to fatty liver), 100-200 mg of an aqueous extract taken from the avocado leaf was

found to significantly reduce total cholesterol and triacylglycerol levels, suggesting that this

extract helps prevent hyperlipidemia and has a hepatoprotective effect in rats [10]. The

antihypertensive effects of an aqueous extract taken from avocado leaves and Cymbopogon

citrates has been studied in rats fed with honey as a source of ethanol and sucrose. This extract

led to a lowering of glucose, total cholesterol, LDL cholesterol and triglyceride levels, revealing

it to be a potential regulator of blood pressure [11]. Several investigations have reported that

quercetin-3-glucoside and quercetin-3-rhamnoside are the main functional compounds

present in avocado leaf [12]. These flavonoids improve endothelial dysfunction and reduce

blood pressure, possibly by increasing the bioavailability of nitric oxide in the blood (potent

vasodilator) [13].

Similarly, guava leaves have been shown to have great benefits in the treatment of cholesterol.

These leaves have a considerable content of tannins, phenols, triterpenes and saponins.

However, the most important bioactive compound that they have been found to contain is

quercetin. This flavonoid has antioxidant, anticancer, anti-inflammatory and cardioprotective

properties [14]. An ethanolic extract of guava leaves with isolated quercetin has been found to

regulate lipid metabolism in rats previously inoculated with carbon tetrachloride. This study

also found this extract to reduce levels of free fatty acids, phospholipids, LDL cholesterol and

triglycerides. In addition, normal HDL cholesterol levels were restored [15]. Further, the effects

of 400 mg/kg of weight of an aqueous extract of guava leaves has been evaluated in mice

induced with diabetes via an injection of streptozotocin. At the end of the investigation, a

decrease in the activity of hormone-sensitive lipase was demonstrated, alongside reduced

levels of LDL cholesterol, triglycerides and total cholesterol. The authors of this study

concluded that this extract improved the lipid profile of the mice, in addition to showing

significant antidiabetic activity [16]. Finally, the effects of including guava leaf powder in the

diet of Wistar mice subjected to a diet high in carbohydrates and fats over an 8-week period

has been evaluated. This study concluded that the powder under study helped to prevent

obesity, improved glucose intolerance, and decreased inflammation and oxidative stress in the

liver of these animals [17].

Turning attention to cinnamon, this is an additive used to improve the smell, flavor and color

of food. This plant is of great importance due to its polyphenol and glutathione content, which

ensures anti-inflammatory and anticancer properties, as well as potentially playing a protective

role against heart disease through the reduction of LDL cholesterol and the increase of HDL

cholesterol [ 18] [19]. The effect of a cinnamon extract on glucose and lipid levels has been

evaluated in Sprague-Dawley diabetic rats. Cinnamon was found to lower blood glucose, lead

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European Journal of Applied Sciences (EJAS) Vol. 11, Issue 3, June-2023

to craving and improve lipid parameters [20]. The aim of the present research was to develop

an infusion made from avocado leaves, guava leaves and cinnamon as a potential alternative

for the treatment of LDL cholesterol.

MATERIALS AND METHODS

Plant Material

The avocado leaves, guava leaves and cinnamon used in the present experiment were

purchased from a supermarket. Avocado and guava leaves were classified according to size,

appearance and the absence of defects. The leaves were then washed and dried at room

temperature. In the same way, the cinnamon sticks were classified according to size,

appearance and the absence of defects.

Dehydration of Avocado and Guava Leaves

The washed and dried avocado and guava leaves were placed in trays within a Rational brand

dehydrator. In the case of guava leaves, a hot air dehydration process was used with the

temperature being set at 45oC. This temperature was selected based on the results obtained in

previous studies [15]. With regards to avocado leaves, the same dehydration process was used,

however, the temperature was set at 40oC, in accordance with that established by previous

investigations [10]. During this treatment, avocado and guava leaves were weighed every 20

minutes until a constant weight was reached.

Formulation of the Infusion

Dehydrated avocado and guava leaves were ground in a Bosch ErgoMixx mill. The same

procedure was carried out with the cinnamon sticks. Three formulations were made. All

formulations contained the same quantity of dehydrated guava leaves, specifically, 1.5 g, in

accordance with outcomes produced by previously conducted research [17]. Likewise, the

amount of cinnamon added to the sample was held constant at 120 mg/kg in all three infusions,

in accordance with outcomes reported by previously conducted research [20].

In the case of avocado leaves, three different amounts were compared. Quantities were selected

based on prior research considering effects on cholesterol control [10] and in order to enable

an examination of different sensory aspects (pleasant taste and aroma for the consumer). The

amounts used were 100 mg/kg, 200 mg/kg and 300 mg/kg.

Amounts of avocado leaf and cinnamon were calculated in consideration of a reference body

weight of 50 kg.

Sensory Analysis

Sensory analysis was carried out via two types of tests. The first was a ranking test and the

second was Basker’s preference test. In order to carry out these tests, 60 tasters were required.

All tasters were given three mugs (formulation 1, 2 and 3) containing 15 ml of the infusion made

from avocado, guava and cinnamon leaves. All samples were coded using a four-digit code.

In the ranking test, tasters were asked to place the tasted samples in descending order based

on their flavor and aroma attributes. In the case of Basker’s test of the "critical value of the

difference between the sum of categories", tasters were requested to evaluate samples using a

pre-established scale indicating preference, where 1 pertained to the most preferred sample