Abstract | | |
Background: Nanotechnology is the specialty associated with material science and biology, rather than a particular field. It entails the method of particles at nanoscale called Nanoparticles, wherein they have control over bulk macroscopic properties of the identical material. The “drug nanocarrier,” selenium possesses strong antibacterial, antioxidant and anti-cancer as well as anti-inflammatory properties. As the medicinal plant Thymus vulgaris possesses a lot of phytochemicals, this study was conducted to assess the anti-inflammatory and antioxidant activity of selenium nanoparticles (SeNps) reinforced with T. vulgaris. Materials and Methods: Anti-inflammatory activity, antioxidant activity of SeNps reinforced with T. vulgaris extract were assessed using bovine serum albumin and 2, 2-diphenyl-1-picrylhydrazyl assay, respectively, at 10, 20, 30, 40, and 50 μL. Results: The values for anti-inflammatory property of nanoparticles were higher than the standard values at 30, 40, and 50 μL concentrations. Percentage of inhibition was highest at 40 μL (87.7%) and 50 μL (92.6%). The values for antioxidant property of nanoparticles were found to be higher than the standard values at 10, 20, and 30 μL concentrations. Percentage of inhibition was highest at 30 μL (68.3%). Conclusion: SeNps reinforced with T. vulgaris extract have a potential as an anti-inflammatory and antioxidant agent and can be used as an alternative to commercially available products.
Keywords: Anti-inflammatory; antioxidant; selenium nanoparticles; Thymus vulgaris
How to cite this article: Pandiyan I, SriS, Indiran MA, Rathinavelu PK, Prabakar J, Rajeshkumar S. Antioxidant, anti-inflammatory activity of Thymus vulgaris-mediated selenium nanoparticles: An in vitro study. J Conserv Dent 2022;25:241-5 |
How to cite this URL: Pandiyan I, SriS, Indiran MA, Rathinavelu PK, Prabakar J, Rajeshkumar S. Antioxidant, anti-inflammatory activity of Thymus vulgaris-mediated selenium nanoparticles: An in vitro study. J Conserv Dent [serial online] 2022 [cited 2023 Jun 4];25:241-5. Available from: https://www.jcd.org.in/text.asp?2022/25/3/241/347343 |
Introduction | |  |
In current years, novel nanotechnologies have seized a lot of attention in research areas as they hold enormous applications in multidisciplinary fields.[1] Nanotechnology is the specialty associated with material science and biology, rather than a specific field. It involves the formulation of particles at nanoscale known as Nanoparticles, where they have control over bulk macroscopic properties of the same material.[2] Many studies have proved the pharmaceutical and nutraceutical values of nanoparticles, in which they interact at cellular as well as molecular levels with a high degree of specificity, sensitivity, and signaling capability.[3] Nanoparticles can modify their physical, chemical, and biological characteristics on account of their large surface-to-volume ratio. “Green chemistry” plays a vital role in fabricating bioengineered nanoparticles, to attain peculiar composition and function.[4],[5]
The green protocol also eliminates the chances of producing unwanted/hazardous by-products rather than the conventional physical and chemical methodologies.[6],[7] The biological synthesis of nanoparticles is emerging as an eco-friendly and exciting approach in the field of nanotechnology. The use of plants for the biosynthesis of nanoparticles does not require high energy or temperatures, and it is easily scaled up for large-scale synthesis, and it is cost-effective too.[8]
Many natural product extracts have been discovered to have a variety of pharmacological and antioxidant results. Hence, here our primary focus was Thymus vulgaris (common thyme), which is locally known in Algeria as “Zaatar,” belonging to the Lamiaceae family, is a perennial herb indigenous to North Africa, Central, and Southern Europe. Its leaves are small, oval, and coiled at the rims, and very fragrant while its flowers appear from May to September and are of a white or pale pink. T. vulgaris L. has been usually used since ancient times in the treatment of burns and poisoning caused by snakes and scorpions. It is an aromatic medicinal herb that broadly utilized in conventional peoples medication for its antimicrobial effects. It is also recognized for its antispasmodic, antiseptic, anthelmintic, diuretic and sedative properties,[9] anti-inflammatory and antalgic effects, antioxidant benefits,[10] and its antifungal properties.[11] It is these different advantages of T. vulgaris L. that form the inspiration driving the current study which aims to assess the protective effects of T. vulgaris L. against oral pathogens.
Selenium, being an indispensable dietary trace element in the human body (about 40 μg Se/day) due to its anti-oxidative as well as pro-oxidative effect, but at high doses selenium can be toxic (400 lg/day).[12] Biosynthesis of selenium nanoparticles (SeNPs), using the diverse range of microorganisms[13] and different plant parts including leaves, flowers, fruits, peel, and seed extracts have been studied extensively.[14],[15] In recent years, there has been growing interest in the preparation and the study of Se-NPs, because these nanoparticles have been found to exhibit interesting (in vitro and in vivo) biological activities, low toxicity, and excellent bioavailability compared with Se(IV) and Se(VI).[16] Importantly, these nanoparticles are involved in the antioxidant defense systems and play an important role in protecting against oxidative stress.[17],[18]
Elemental selenium in the form of nanoparticles additionally confirmed antibacterial activity toward Staphylococcus aureus, a key pathogen in hospital-acquired and medical device-associated infections, even some researchers investigated that SeNPs are more effective with lower toxicity in comparison with silver nanoparticles.[19],[20],[21] However, there are no reports on the biosynthesis of SeNPs from T. vulgaris that are generally utilized in folk medicine since ancient times. Hence, the aim of this study is to analyze the combined anti-inflammatory and antioxidant activity of biosynthesized SeNps prepared from T. vulgaris-An in vitro study.
Materials and Methods | |  |
Ethical approval
All experimental procedures conducted by the authors were approved by the Ethics Committee of Saveetha University, SIMATS.
Collection and preparation of plant extract
Powdered thymus leaves were purchased from the market of South India and identified and authenticated by Botanists. The obtained powder of T. vulgaris was stored in an airtight container. One gram of T. vulgaris powder is diluted with 40 ml of distilled water and boiled for 20 min. The extract was filtered using Whatman No. 1 filter paper and allowed to stand undisturbed for 20 min. Then, the plant extract was moved to an impenetrable container and refrigerated overnight, and used for green synthesis.
Preparation of selenium nanoparticle extract
Thirty Mm of sodium selenite is weighed and mixed with distilled water of 60 ml. The sodium selenite solution was mixed with 40 ml of filtered plant extract and was permitted to stand in a magnetic stirrer for 1 h and kept in a shaker for intermixing of the particles to obtain green synthesis. Ultraviolet (UV) spectrometers periodically monitored the reduction of sodium selenite to SeNps. The change in color was noted visually and photographs were taken.
Preparation of nanoparticle powder
Using Lark refrigerated centrifuge, the SeNps solution is centrifuged at 8000 rpm for 10 min, and therefore, the pellet was collected and washed twice with the distilled water. The final purified pellet is collected and dried at 100–1500°C for 24 h, and finally, the nanoparticles powder is collected and stored in an airtight Eppendorf tube.
Evaluation of anti-inflammatory activity by albumin denaturation assay
Test group
10, 20, 30, 40, and 50 μL of the nanoparticles were taken in 5 test tubes separately. Two milliliters of 1% bovine serum albumin (BSA) was added to each test tube. 390, 380, 370, 360, and 350 μL of distilled water were added to the test tube containing 10, 20, 30, 40, and 50 μL of nanoparticles, respectively.
Control group
Two milliliters of dimethyl sulfoxide was added to 2 mL of BSA solution.
Standard group
A volume of 10, 20, 30, 40, and 50 μL of diclofenac sodium was taken in 5 test tubes, respectively. Two milliliters of 1% BSA was added to each test tube. The test tubes were incubated for 10 min at room temperature. Then, they were incubated in a water bath at 55°C for around 10 min. The absorbance was measured in the UV spectrophotometer at 660 nm.
Percentage inhibition was calculated using the following formula:

Evaluation of anti-oxidant activity
Test group
A volume of 10, 20, 30, 40, and 50 μL of the nanoparticle was taken in 5 test tubes, respectively. To each test tube, 1 ml of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) was added. 1990, 1980, 1970, 1960, and 1950 μL of 50% methanol solution was added to the test tube containing 10, 20, 30, 40, and 50 μL of nanoparticles, respectively.
Control group
One milliliter of DPPH was added to 2 mL of methanol solution.
Standard group
The standard used was ascorbic acid. The test tubes were incubated for 20 min in a dark cupboard. Absorbance was measured at 517 nm in the UV spectrophotometer.
Percentage inhibition was calculated using the following formula:

Results | |  |
[Figure 1] depicts the anti-inflammatory property of SeNps reinforced with T. vulgaris extract at various concentrations compared with the standard values. It was found that the values for anti-inflammatory properties of nanoparticles were higher than the standard values at concentrations 30, 40, and 50 μL. Percentage of inhibition was 35.2% at 10 μL concentration, 53.5% at 20 μL, and 78.2% at 30 μL, and highest at 40 μL (87.7%) and 50 μL (92.6%). | Figure 1: Anti-inflammatory property of selenium nanoparticle reinforced with Thymus vulgaris at various concentration compared with standard values
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[Figure 2] depicts the antioxidant property of SeNps reinforced with T. vulgaris extract at various concentrations compared with the standard values. Comparing with the standard concentrations at 10, 20, and 30 μL, the values for the antioxidant property of nanoparticles were found to be higher. Percentage of inhibition was 54.7% at 10 μL concentration, 63.5% at 20 μL, 68.3% at 30 μL, 72.5% at 40 μL, and 65.3% at 50 μL. | Figure 2: Anti-oxidant property of selenium nanoparticle reinforced with Thymus vulgaris at various concentration compared with standard values
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Discussion | |  |
There has been a rapid evolution of nanoparticle synthesis recently as compared to the early part of the century.[22] Earlier, physio-chemical methods were involved in nanoparticle synthesis. Although less time is utilized for synthesizing large quantities of nanoparticles using conventional physical and chemical methods, toxic chemicals are required as capping agents to maintain stability, thus leading to toxicity in the environment. Keeping this in consideration, green nanotechnology using plants is emerging as an eco-friendly alternative, as plant extract-mediated biosynthesis of nanoparticles is cost-effective.[23] Therefore, this experiment was carried out to evaluate the anti-inflammatory and antioxidant properties of SeNps reinforced with T. vulgaris extract.
Percentage of inhibition of protein denaturation (anti-inflammatory activity) was 35.2% at 10 μL concentration, 53.5% at 20 μL, 78.2% at 30 μL, and 87.7% at 40 μL, and highest at 50 μL (92.6%). Percentage of inhibition of DPPH free radicals (antioxidant activity) was 54.7% at 10 μL concentration, 63.5% at 20 μL, 68.3% at 30 μL, 72.5% at 40 μL, and 65.3% at 50 μL.
A lot of artificial drugs such as NSAIDs which are used against inflammation are effective, but they have many side effects such as gastrointestinal and renal damage.[24] The functional groups such as alcohol and polyphenols involved in the reduction of selenium ion to SeNPs were detected with FT-IR analysis. Recent reports on the synthesis of SeNPs by the aqueous extract of Leucas lavandulifolia leaf, Bougainvillea spectabilis flower, and dried Vitis vinifera fruits highlighted the probable role of phytochemicals such as terpenoids, sugar, amines, alcohols, phenols, and carboxylic acids in the reduction of selenium ions and stabilization of SeNPs.[25],[26],[27]
In a study done by El-Ghazaly et al., regarding the anti-inflammatory effect of SeNps on the inflammation induced on irradiated rats, Nano-Se were administered orally in a dose of 2.55 mg/kg. It has been found that nano-Se lessened the elevating inflammation in both irradiated and nonirradiated rats.[3] Melatonin-SeNPs treatment decreased pathological abnormalities of the liver, proinflammatory cytokines, and splenocyte proliferation. At a lower concentration, the combination of silymarin and selenium nanoparticles is an excellent candidate possessing both anti-inflammatory and antioxidant properties.[28]
The SeNps have been proved to be biocompatible to humans by various reports. One such study which was conducted to check about the role of selenium as a protective agent against where people were administered with low dose of antioxidant vitamins and minerals that included vitamin E, vitamin C, β-carotene, selenium, and zinc on a daily basis and after a certain period it was reported that people who were given these antioxidant vitamins and minerals had a reduced incidence of prostate cancer compared to the people who received placebo.[29] Nano-Se exhibited an excellent bioavailability because of its high catalytic efficiency, strong adsorbing ability, and low toxicity. This study has proved the anti-inflammatory and antioxidant properties of SeNps synthesized using T. vulgaris.[30] The study has certain limitations of being in vitro, so it cannot be assumed that the results of, anti-inflammatory and antioxidant activites could be translated into clinical effectiveness.
Recommendations
In further studies, in vivo trials are recommended in animals and further proceed to clinical trial with people's acceptance values as well.
Conclusion | |  |
Findings from this study suggest that SeNps reinforced with T. vulgaris extract have the potential as an anti-inflammatory and antioxidant agent and can be used as an alternative to commercially available products.
Acknowledgment
We take pleasure to thank Saveetha Dental College for giving us permission to conduct the study.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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Correspondence Address: Dr. Sri Sakthi D Department of Public Health Dentistry, Saveetha Dental College and Hospital, 162, Poonamalee High Road, Chennai - 600 077, Tamil Nadu India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/JCD.JCD_369_21

[Figure 1], [Figure 2] |