Potential Antidiabetic Properties of Syzygium Cumini (L.) Skeels Leaf Extract-Mediated Silver Nanoparticles

Research Article

Austin J Anal Pharm Chem. 2024; 11(1): 1168.

Potential Antidiabetic Properties of Syzygium Cumini (L.) Skeels Leaf Extract-Mediated Silver Nanoparticles

Santosh Mallikarjun Bhavi1; Shubha K Mirji1; Bothe Thokchom1; Sapam Riches Singh1; Raju B Maliger2; Shivanand S Bhat3; Pooja Joshi1; BP Harini4; Ramesh Babu Yarajarla1*; Salim Al Jadidi2

1Drosophila and Nanoscience Research Laboratory, Department of Applied Genetics, Karnatak University, Dharwad, India

2Department of Mechanical and Industrial Engineering (MIE), University of Technology and Applied Science (UTAS), Muscat, Sultanate of Oman

3Department of Botany, Smt. Indira Gandhi Government First Grade Women’s College, Sagar, India

4Department of Zoology, Bangalore University, Bangalore, India

*Corresponding author: Ramesh Babu Yarajarla Department of Applied Genetics, Karnatak University, Dharwad, Karnataka – 580003, India. Email: rameshy@kud.ac.in

Received: January 17, 2024 Accepted: February 17, 2024 Published: February 24, 2024

Abstract

This study explores the use of Syzygium cumini (L.) Skeels plant aqueous leaf extract as a reducing agent, which enables the green synthesis and comprehensive characterization of silver nanoparticles (AgNPs). The results indicated that the synthesized AgNPs were spherical in shape with an average size of 27.5 nm and a silver content of approximately 43.18%. The AgNPs exhibited promising antidiabetic and wound-healing properties. The antidiabetic activity, measured through glucose uptake and a-amylase inhibition assays, showed values of 80.08% and 83.91%, respectively. Additionally, the cytotoxicity assessment revealed that the AgNPs exhibited good biocompatibility even at higher doses, indicating their lower toxicity profile. Furthermore, the AgNPs demonstrated wound-closure percentages of 27.59% and 92.48% at 12 h and 24 h respectively, post-treatment, indicating that they were as effective as that of the standard ascorbic acid. These findings suggest that Syzygium cumini-mediated AgNPs have significant potential for applications in antidiabetic and wound-healing treatments.

Keywords: Silver nanoparticles; Syzygium cumini; Antidiabetic; Wound-healing; Cytotoxicity

Introduction

Diabetes Mellitus (DM) is a complex disease characterized by high blood glucose levels. The primary cause of diabetes is oxidative stress and an increase in Reactive Oxygen Species (ROS) [1]. Untreated diabetes can lead to organ damage, including heart, eyes, and kidneys. There are two main categories of diabetes: impaired insulin secretion and insulin resistance [2]. In spite of the available synthetic drugs, controlling diabetes remains challenging globally [3]. Amylase, an enzyme involved in glucose metabolism, is produced by salivary glands and the pancreas [4]. Current inhibitors of a-amylase and glucosidase used in clinical practice have side effects, limiting their effectiveness in diabetes treatment [5]. Reduced activity of facilitative Glucose Transporters (GLUTs) contributes to insulin resistance and Type II diabetes [6]. Therefore, alternative approaches with fewer side effects are needed. Chronic wounds in individuals with diabetes exhibit impaired healing due to various factors, including hypoxia, dysfunctional cells, impaired angiogenesis, ROS damage, decreased immune resistance, and neuropathy [7,8]. Nanoparticles, especially AgNPs, are becoming increasingly popular due to their various commercial and pharmacological benefits, such as their nano size, which imparts unique physicochemical properties including optical, electrical, and thermal characteristics, as well as high electrical conductivity and biological properties [9]. The properties of AgNPs depend on their size, shape, distribution, and surface characteristics, which can be adjusted by controlling the synthesis process [10]. Green synthesis has emerged as an eco-friendly and sustainable approach to generating nanoparticles, where plant extracts, microbes, or enzymes are used as reducing and stabilizing agents. AgNPs synthesized via green synthesis have shown promising results in various fields, including antidiabetic applications [11].

Syzygium cumini (L.) Skeels, commonly known as Syzygium jambolanum or Eugenia cumini, is a widely used medicinal plant in traditional medicine for treating diabetes [12]. Belonging to the Myrtaceae family, it goes by various names including Java Plum, Black Plum, Jambul, Jamun, Jamblang, and Indian Blackberry [13]. This remarkable plant is enriched with a range of beneficial phytochemicals such as flavonoids, terpenoids, and phenolics. It includes compounds such as sitosterol, betulinic acid, crategolic acid, quercetin, myricetin, methylgallate, and kaempferol, which are known for their potential antidiabetic effects [14]. Traditional medicinal system of medication have long recognized the effectiveness of Syzygium cumini in treating various health conditions, viz. leucorrhea, gastric disorders, fever, piles, wounds, and dental, digestive, and skin disorders [15]. Its historical usage and the presence of these beneficial phytochemicals make Syzygium cumini an intriguing natural remedy with potential applications in diabetes treatment.

In the current study, we conducted experiments to examine the potential of green-synthesized AgNPs using Syzygium cumini plant extract. We characterized the nanoparticles and assessed their antidiabetic effects, wound-healing properties, and cytotoxicity. Our goal was to explore the diverse biological applications of these nanoparticles in diabetes management.

Methodology

Chemicals and Materials

The study involved the utilization of a range of solvents and chemicals of high quality. These included a precursor solution of 1mM AgNO3, obtained in analytical grade, DMEM media (Dulbecco’s Modified Eagle Medium) produced by Sigma Aldrich, MTT reagent (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide), DMSO (Dimethyl Sulfoxide), and Nutrient broth sourced from Hi-media, India. All solvents and chemicals used in the study met the standards of analytical grade quality. Healthy and disease-free leaves of Syzygium cumini were collected from an area near the Western Ghat in Karwar, Karnataka, India, at coordinates 14° 53' 57'' N, 74° 07' 49'' E. The plant's identification and authentication were carried out by Dr. Shivanand S. Bhat, Taxonomist at Smt. Indira Gandhi Government First Grade Women’s College, Sagar, Karnataka, India (Specimen Acc. No: IGGFWC/Myr-044). The rat myoblast cell line L6 was obtained from the National Centre for Cell Science, located in Pune, Maharashtra, India.

Preparation of Aqueous Leaf Extract

The leaves were meticulously cleaned and subsequently dried in the shade for a few days. Once dried, they were finely ground into coarse powder and kept at room temperature. To prepare the extract, 15g of the coarse powder was mixed with 200 mL of distilled water and heated in a water bath at 70°C for 30 min. The resulting mixture was then filtered using a muslin cloth and Whatman No. 1 filter paper to remove solid particles, yielding a clear extract. This extract was appropriately stored at a temperature of 4°C for future use.

Synthesis of Silver Nanoparticles

The AgNPs were synthesized using a green and eco-friendly method involving the aqueous extract of leaf mixed with a 1 mM AgNO3 solution in a 1:9 ratio. The reaction mixture was kept in the dark at room temperature and incubated in a water bath at 70OC for 1 h, resulting in a color transition from yellow to dark brown. Centrifugation at 10,000 rpm for 12 min and re-dispersion in double distilled water were performed multiple times to remove impurities, and the resulting powder was dried and preserved. This bio-reduction approach utilizing plant extracts offers an environmentally-sustainable and cost-effective alternative for AgNPs synthesis, as reported in previous study [16], and does not involve harmful chemicals, thus making it a pure and eco-friendly process.

Characterization

The green synthesized AgNPs were thoroughly characterized using various techniques in the present study. All characterizations were performed using a single batch of synthesized AgNPs. To confirm the reduction of metal ions to metal in the synthesized AgNPs, UV-Vis spectrophotometry was used, and spectra were measured in the range of 200-800 nm with distilled water used as a blank. To unveil the precise size of the produced AgNPs, X-ray diffraction (XRD) analysis was conducted using a RIGAKU Smart lab SE instrument with Cu_Ka_1D radiation as the source. The diffraction pattern was recorded in the range of 5° to 90° as 20 angles. Particle size analysis and zeta potential were conducted using a HORIBA SZ-100 instrument to investigate the size distribution, surface charge, and stability of the nanoparticles in colloids. The morphology of the synthesized AgNPs was observed using Transmission Electron Microscopy (TEM) at an accelerating voltage of 120 kV. High-Resolution TEM (HRTEM) images were also obtained using the same TEM instrument (JEOL JEM-2100 PLUS). To investigate the near-surface elements and elemental proportions in the synthesized nanoparticles, Energy Dispersive X-ray Analysis (EDX) was used. The EDX analysis was conducted to determine the elemental composition and distribution of the elements within the nanoparticles. Fourier Transform Infrared (FT-IR) spectrophotometer was utilized to identify the functional groups present in the synthesized nanoparticles. The synthesized silver nanoparticles powder sample was loaded into the FT-IR spectrophotometer and scanned in the range of 400 to 4000 cm-1 using the Nicolet iS10 FTIR Spectrophotometer.

Biological Activities

Glucose uptake assay: The glucose uptake assay for AgNPs involved the use of yeast cells as an in vitro screening method for hypoglycemic effects. Yeast cells were selected due to the complexity of glucose transport across their cell membrane, which involves facilitated diffusion. To conduct the assay, Saccharomyces cerevisiae cells were suspended in distilled water and centrifuged. Different concentrations of the test sample (50, 100, 150, 200 & 250 μg mL-1) were added to test tubes along with glucose. The tubes were incubated at 37- for 60 min, followed by centrifugation (2500×g.5min), and the concentration of glucose was estimated by determining the absorbance at 540 nm by a spectrophotometer. Metformin was used as a standard drug for comparison.

The % increase in glucose uptake by yeast cells was calculated using the formula:

% Increase in glucose uptake =

a-amylase Inhibition Assay: To measure the activity of a-amylase enzyme, the hydrolysis of starch in the presence of a-amylase enzyme was quantified using 3,5-dinitrosalicylic acid (DNS) reagent. Firstly, samples were mixed with a-amylase and starch in PBS solution, along with different concentrations of the test samples and a standard solution such as Acarbose. The mixture was then incubated at room temperature for 10 min. Control samples were also prepared with and without amylase. To stop the reaction, DNS solution was added to the mixture, and the mixture was boiled in a water bath for 5 min. The absorbance of the resulting solution was measured at 540 nm using a UV-visible spectrophotometer.

The % of enzyme inhibition can be calculated using the formula [17]:

% of a-amylase inhibition =

If the sample extract possesses a-amylase inhibitory activity, the intensity of the color produced by the DNS reagent will be more, indicating a higher percentage of enzyme inhibition.

In vitro cytotoxicity: An MTT assay was employed to evaluate the cytotoxicity of AgNPs and a plant extract on L929 cells. This colorimetric assay measures the reduction of MTT to formazan by mitochondrial dehydrogenases in viable cells. L929 cells were seeded in a 96-well microtiter plate at a density of approximately 10,000 cells per well. Subsequently, the plate was incubated for 24 h, enabling the cells to establish attachment and promote their growth. Different concentrations of the test drug (ranging from 100 to 500 μg mL-1 for both extract and AgNPs) were added to the cells, and the plate was incubated for a defined period. Next, 100 μL of 10% MTT reagent was added to each well, and the plate was incubated for 3 h.

The formazan crystals were dissolved in DMSO and their absorbance was measured at 570 nm (with a reference wavelength at 630 nm) using a microplate reader. This enabled the generation of a dose-response curve and determination of the median inhibitory concentration (IC50 value). A lower IC50 value indicates higher cytotoxicity, while a higher IC50 value indicates lower cytotoxicity.

Wound Healing activity by Scratch assay: The wound healing activity of AgNPs and plant extract can be assessed using the Scratch assay, which involves using the L929 cell line. The cells were initially cultured at 37°C in a 5% CO2 atmosphere for 24 h to allow them to reach ~100% confluence as a monolayer. When performing the Scratch assay, it was assured that the long axis of the tip was always perpendicular to the bottom of the well while scratching across the surface. After scratching, the wells were washed twice with DMEM media and 1X PBS. 25 μL of AgNPs (37.55 μg), plant extract (42.26 μg), and standard ascorbic acid (15 μg), respectively, were added to the wells along with 1 mL of fresh media. It was further incubated at 37°C and observed for wound closure at different time intervals (0 h, 12 h, and 24 h).

Results and Discussion

Ultraviolet-Visible Spectroscopic Analysis (UV-Vis)

Confirmation of AgNPs formation was achieved through UV-Vis spectroscopy measurements. As silver nanoparticles are known to exhibit absorption at wavelengths between 400 to 500 nm [18], the reaction mixture in this study displayed a peak at 465 nm, as shown in Figure 1a, providing conclusive evidence for the presence of AgNPs. UV-Vis spectroscopy serves as a valuable analytical tool for confirming the reduction of Ag+ to Ag0 [19].