Free Radicals and Antioxidants

A Comprehensive Review on the Antioxidant Properties of Green Synthesized Nanoparticles: In Vitro and In Vivo Insights

Aditya Jain — 2025-01-21

The use of green-synthesized nanoparticles has emerged as a promising avenue for enhancing antioxidant activity in various applications, including medicine, environmental protection and food preservation. This review provides a comprehensive overview of the role of nanotechnology in antioxidant activity, focusing on the green synthesis of nanoparticles using plant-based extracts. The paper begins by discussing the types of antioxidants, categorizing them into enzymatic, non-enzymatic and synthetic compounds and highlighting their mechanisms of action in scavenging free radicals. Various antioxidant assay methods, including DPPH, ABTS and FRAP, are examined for their effectiveness in evaluating antioxidant potential. The review also delves into the role of medicinal plants in the green synthesis of nanoparticles, detailing how bioactive compounds in plant extracts contribute to the reduction and stabilization of metal ions into nanoparticles. The types of green synthesized nanoparticles covered include silver, gold, titanium oxide, starch, iron oxide, zinc oxide, copper, cerium oxide, nickel oxide, selenium, platinum and palladium, each with unique properties that influence their antioxidant activity. The interaction between these nanoparticles and free radicals, as well as their potential synergistic effects with other antioxidants, is discussed. Finally, the review highlights the benefits of using green synthesis methods over conventional chemical synthesis, emphasizing sustainability, cost-effectiveness and the reduced environmental impact. This work underscores the growing potential of green-synthesized nanoparticles as powerful antioxidant agents, offering new insights into their applications and future directions in both scientific research and industrial innovation.

Antioxidants, Radical Scavenging, and Their Impact on Oxidative Stress

Franklyn Okechukwu Ohiagu — 2025-01-21

Antioxidants impede free radical chain reactions and thereby retard and prevent oxidative cellular damage. The present review provides an overview of the basic mechanisms by which antioxidants scavenge free radicals and describes the basic methods for measurement of antioxidant activities against free radicals as well as the underlying chemistry and pathologies linked with oxidative stress. This review was sourced online from scientific search engines using appropriate keywords. For appropriate measurement of antioxidant capacity, with respect to reaction mechanisms involved in the free radical reduction process, exclusive application of HAT, SET methods, and/or a combination of both HAT/SET methods should be considered. The human body is equipped with an antioxidant defence system to mitigate or prevent free radical-induced cellular damage through free radical scavenging mechanisms such as inhibition of enzyme activity involved in free radical generation, activation of intracellular enzymatic antioxidant activity, metal ion chelation, as well as inhibition of protein modification, DNA damage, and lipid peroxidation. Impaired antioxidant activity is associated with chronic diseases such as cardiovascular diseases, diabetes mellitus, inflammatory disease, cancer, cataracts, Alzheimer’s disease, autism, and ageing. Overexpression of enzymatic antioxidants, as demonstrated in mutant mice models, could serve as a novel alleviative measure against the development of pathological conditions associated with oxidative stress.

2,3,4-Trihydroxybenzoic Acid, an Antioxidant Plant Metabolite Inhibits Cancer Cell Growth in vitro: Potential Role in Cancer Prevention

Mina Akter — 2025-01-21

Background: Colorectal Cancer (CRC) is the third most common cause of cancer death in the US and more than 1 million people are diagnosed with this disease every year worldwide. In this regard, flavonoids and their degradation products, namely Hydroxybenzoic Acids (HBAs) continue to be evaluated for the prevention of CRC. Hydroxybenzoic acids are also present as secondary plant metabolites in many fruits and vegetables. In the present study, we determined the ability of 2,3,4-THBA, which is present in fruits and vegetables and known to have antioxidant properties, to inhibit cancer cell growth in HCT-116 colon and MDA-MB-231 breast cancer cells. Materials and Methods: Cell proliferation assays and clonogenic assays were carried out to determine the effect of 2,3,4-THBA on cancer cell growth. Cell morphology was determined using light microscopy. Western Blot experiments were performed to determine the expression levels of Human Epidermal Growth Factor Receptor-type 2 (HER2), Fibroblast Growth Factor Receptor (FGF-R), Cyclin-Dependent Kinase (CDK) inhibitors p21 and p27. In silico studies were performed to determine the potential binding of 2,3,4-THBA to CDK1, CDK2, CDK4 and CDK6. Results: We demonstrate that 2,3,4-THBA dose-dependently inhibited HCT-116 colon and MDA-MB-231 cancer cell proliferation. It also significantly decreased the colony formation in both cancer cell lines. Treatment of cells with 2,3,4-THBA did not alter the levels of HER-2 and FGF-R; however, it induced the levels of expression of CDK inhibitors p21 and p27 in a dose-dependent fashion. In silico studies suggested that 2,3,4-THBA has the potential to bind to CDK1, CDK2, CDK4 and CDK6 through interactions with specific amino acids. Conclusion: The growth inhibitory effect of 2,3,4-THBA on cancer cells may occur partly through induction of CDK inhibitors p21 and p27, and through direct binding to CDKs involved in cell cycle regulation. These data suggest that 2,3,4-THBA from plant sources has the potential to be used in cancer prevention.

A Quantitative Analysis of in vitro Antioxidant Capacity and Antioxidant Enzymes in Bacopa monnieri (L.) Wettst

Ramya Shanmugam — 2025-01-21

Background: Bacopa monnieri (L.) Wettst is an herbal plant used predominantly in Ayurvedic medicine. Though this plant has diverse pharmacological properties it is pivotal to acknowledge its total antioxidant capacity and enzymatic quantification which are not well established. Therefore, the principal objective of this study is to elucidate the antioxidant capacity in five different solvent extracts including ethanol, acetone, chloroform, petroleum ether and aqueous, further to quantify chlorophyll and iron content and the antioxidant enzymes of B. monnieri fresh stem extracts. Materials and Methods: The comparative identification of the antioxidant capacities of five different extracts ethanol, acetone, chloroform, petroleum ether and aqueous of B. monnieri stem was investigated through phosphomolybdate assay (Total antioxidant capacity). The fresh stem extracts were quantified for chlorophyll and iron content using the acetone method and the thiocyanate method respectively, furthermore quantified antioxidant enzymes are Superoxide Dismutase (SOD), Catalase (CAT), Peroxidase (Px), Ascorbate Oxidase (AO) and Polyphenol Oxidase (PPO). Results: The results showed the fresh stem extract has a total chlorophyll content of 0.2720±0.01 mg/g and the iron content is greatly obtained in distilled water than in 30% sulphuric acid. The ethanol extract exhibited greater antioxidant capacity with the IC₅₀ value of 16±0.3 μg/mL. The enzymatic capacity of SOD, CAT, Px, AO and PPO resulted in 10.83±0.003 units of fresh weight, 41.03±0.004, 2.044±0.003, 56.15±0.003 and 57.21±0.003-unit mg-1 protein min-1 respectively. Conclusion: The results indicate that B. monnieri may serve a strong prophylactic action against ROS-related diseases with its remarkable enzymatic defense system and antioxidant capacity.

Wound-Healing Activity of Herbal Ointment Containing the Root Extracts of Astragalus propinquus in Sprague Dawley Rats

Varatharajan Rajavel — 2025-01-21

Background: Astragalus propinquus is an herb belongs to the family of Fabaceae. Astragalus propinquus is commonly known as Mongolian milkvetch in English and in Chinese it is called huang qi. Astragalus propinquus is a traditional Chinese herbal medicine with ancient origins, derived from the various roots of Astragalus species native to China Mongolia, North America and Korea. A. propinquus possesses cardiotonic, immunostimulant, hepatoprotective and anti-aging activities. The aim of our study was to assess the wound-healing properties of herbal ointment containing the root extracts of A. propinquus in Sprague Dawley (SD) rats. Materials and Methods: A. propinquus roots were collected dried, powdered and extracted with ethanol and methanol for 7 days by cold maceration method. A.propinquus ointment was prepared using wool fat, hard paraffin, cetostearyl alcohol and white soft paraffin. Ointment formulation was applied once daily on the excision wound on SD rats for 20 days. During the study, the animals were weighed on a regular basis every 5 days. Every fourth day after wound formation, wound contraction was measured as a percentage contraction. In the excision wound model, the wound area was measured by tracing the wound margins onto a transparent sheet and assessing it using millimeter-based graph paper. Results: On day 20, the non-treatment group showed a wound contraction was 90.04±1.06 %. The ethanolic extract group and methanolic extract group showed a significant increase in wound contraction which was 98.44±0.99% and 96.63±0.17 % as compared with non-treatment group, moreover the standard drug treatment group also showed the significant contraction with the percentage of 99.88±0.12%. Conclusion: Plant based ointment exhibited shows significant wound healing activity in rat excision wound model.

Evaluation of Free Radical Scavenging Efficacy of Siddha Formulation Pirandai uppu Using in vitro Antioxidant Assay

Kanimozhi Selvakumaran — 2025-01-21

Background: Concentrated forms of the plant extracts such as sathu/uppu possess effective medicinal properties. On concentrating the active principles were also get doubled. These organic substances are valuable resources for contemporary drug research. Pirandai uppu is the salt/ash extracted from Cissus quadrangularis. Pirandai uppu is used to cure a number of illnesses, including hemorrhoids, peptic ulcers, arthritis and diarrhea. Hence, the present study aims to assess the antioxidant property of Pirandai uppu from various antioxidant assays. Materials and Methods: The antioxidant properties of Pirandai uppu were assessed using DPPH, Nitric Oxide Radical Scavenge Assay, ABTS and Hydrogen Peroxide Radical Scavenge Assay. Percentage of inhibition and IC50 values were calculated and compared with that of standards. Results: The percentage inhibition of Pirandai uppu from DPPH radical scavenging activity ranges from 15.935±4.314 to 78.45±18.05%, The percentage inhibition of Pirandai uppu from NO radical scavenging activity ranges from 23.28±6.137 to 70.26±8.898%, The percentage inhibition of Pirandai uppu from ABTS radical scavenging activity ranges from 15.72±24.67 to 75.16±22.1% and The percentage inhibition of Pirandai uppu from hydrogen peroxide radical scavenging activity ranges from 16.234±0.9669 to 68.87±0.9743%. Conclusion: The siddha formulation Pirandai uppu has promising free radical scavenging activity in the estimated assays. Thus, Pirandai uppu posses a potent antioxidant property. This may be due to rich flavonoid content in Cissus quadrangularis.

Methaemoglobin and Malondialdehyde Levels of Human Erythrocytes Incubated with Acetylsalicylic Acid

Marika Louise Graham — 2025-01-21

Background: MetHb and MDA are biomarkers for erythrocyte redox status and membrane lipid peroxidation, respectively. This present study aims to investigate the levels of human erythrocyte redox status and membrane lipid peroxidation indicators in the presence of ASA over time using in vitro models. Materials and Methods: The %MetHb was evaluated by measuring the absorbance of human erythrocyte suspension at λmax=630 nm and 540 nm. Human erythrocytes were incubated in 0.125 mg/mL, 0.25 mg/mL and 0.5 mg/mL ASA over a 6 hr incubation period. The human erythrocyte MDA concentration was measured using the TBARS assay. Results: The %MetHb of human erythrocytes following 3 hr of incubation with 0.125 mg/mL ASA gave a peak value of 2.70±1.36%, indicating a relative significant (p<0.05) increase of 45.16% compared with the control samples. Furthermore, an increase in the incubation time resulted in a decrease in erythrocyte %MetHb, although not to the levels observed at the beginning (t=0 hr) of incubation with ASA. Conversely, MDA concentration of human erythrocytes was 4.45±0.89 μM after 3 hr of incubation with 0.125 mg/mL ASA, showing a significant (p<0.05) decrease of 27.88%. Conclusion: The present study showed a negative correlation between %MetHb and MDA levels in human erythrocytes incubated with ASA over time, suggesting that the erythrocytes redox status did not specifically induce membrane lipid peroxidation.

Evaluation of the Antioxidative and Qualitative Properties of the Tinospora cordifolia

Arthi Boro — 2025-01-21

Background: Tinospora cordifolia is a perennial shrubby creeper, a member of the Menispermaceae family. It is a plant containing various phytochemical compounds and is used in traditional medicine. Materials and Methods: In the following study the qualitative analysis of the phytochemical compounds found in the stem of T. cordifolia is studied and FRAP, DPPH and ABTS assay is carried out to analyse the antioxidative activity of the three solvents including aqueous, ethanol and acetone of T. cordifolia stem. Results: In a qualitative analysis of the T. cordifolia stem the compounds carbohydrates, alkaloids, flavonoids, reducing sugar, phenolic compounds, tannins, saponins, phytosterol, lignin, quinone, anthocyanin and coumarins are found present. In FRAP among the three solvent extracts ethanolic extract of T. cordifolia stem performed better followed by acetone and aqueous. In DPPH the aqueous extract of T. cordifolia stem exhibited better antioxidative activity with IC₅₀ 136 μg/mL followed by acetone and ethanol extract. In the ABTS assay too the aqueous extract showed better antioxidative properties with IC₅₀ 48.150 μg/mL followed by acetone and ethanol extract of the plant. Conclusion: The above study indicates that T. cordifolia has medicinal properties due to the existence of different phytochemical constituents. In antioxidative activity analysis, the aqueous extract of the T. cordifolia stem performs better than the other two extracts, which indicates that the aqueous extract has good antioxidative properties. However, further analysis is needed.