In vitro Cytotoxicity and Antioxidant Study of Rhodomyrtus tomentosa (Aiton) Hassk. Ethanolic Leaf Extract on LPS-induced RAW 264.7 Macrophage Cells

Aims: Ethanol extract of Rhodomyrtus tomentosa leaves found specifically on Malaysian soil was used to further investigate the antioxidant properties and cytotoxicity against RAW 264.7 macrophage cells in the search for a safer and effective natural antioxidant agent. Study Design: Antioxidant potential of R. tomentosa were analyzed through series of spectrometric assays and cell-based bioassays model. Place and Duration of Study: This study was carried out at Faculty of Pharmacy, Universiti Teknologi MARA (UiTM), Puncak Alam Campus, 43200, Selangor, Malaysia from the year of 2019 to 2021. Methodology: R. tomentosa leaves were subjected to extraction with 95% ethanol. The extracts were then denoted as ethanolic leaves extract of R. tomentosa or EtRT extract. EtRT extract were then screen for its antioxidant activity (AOA) and total antioxidant capacity (TAC) through DPPH radical scavenging assay and ferric reducing antioxidant power (FRAP) assay. After that, EtRT extract were brought to observe its toxicity against RAW 264.7 macrophage cells in MTT assay. Once their toxicity was obtained, EtRT extracts were finally tested for their ability to inhibit intracellular reactive oxygen species (ROS) and nitric oxide (NO) inhibition in RAW 264.7 macrophage cells to further analyze their antioxidant properties. Results: In this study, EtRT extracts dose dependently showed the ability to scavenge DPPH radicals and reduce ferric ions during DPPH radicals scavenging activity assay and ferric reducing antioxidant power assay (FRAP), respectively. In DPPH radical scavenging activity assay, EtRT extracts showed EC50 value at 12.37 ± 1.73 µg/mL with ARP value of 0.08 almost as near as ascorbic acid’s ARP value which is 0.09. Further into the study, EtRT extract were not cytotoxic to RAW 264.7 macrophage cells at concentrations 3.91 µg/mL and lower which showed more than 86.4% cell viability with IC50 value at 204.70 ± 5.30 µg/mL. EtRT extract possessed the ability to inhibit ROS production on LPS-induced RAW 264.7 macrophage cells at 7.813 µg/mL and lower, with the highest concentration can reduce up to 30.20% ± 1.01 out of the total ROS produced by the induced cells. Furthermore, EtRT extract also have evidenced that it is able to significantly inhibit NO production by the LPS-induced RAW 264.7 macrophage cells at 7 µg/mL and lower being the highest at 56.73% ± 0.11 inhibition of the highest concentration tested. Conclusions: This study suggests that EtRT extracts have the potential to reduce LPS-induced oxidative stress due to the antioxidant activities of phenolic compounds in the extracts, and that at low doses, EtRT extracts had low to no cytotoxicity on RAW 264.7 macrophage cells. As a result, EtRT extract could be a promising natural medicinal agent for the treatment of oxidative stress.

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Physicochemical and Antioxidant Properties of Iranian Commercial Honeys

Current Nutrition & Food Science ◽

10.2174/1573401314666180606090908 ◽

2019 ◽

Vol 15 (7) ◽

pp. 700-706

Author(s):

Mehdi Zarei ◽

Ali Fazlara ◽

Maedeh S. Hamedani

Keyword(s):

Reducing Sugars ◽

Radical Scavenging Activity ◽

Antioxidant Properties ◽

Radical Scavenging ◽

Total Phenolic ◽

Dpph Radical ◽

Dpph Radical Scavenging Activity ◽

Antioxidant Power ◽

Ferric Reducing Antioxidant Power ◽

Dpph Radical Scavenging

Background: All over the world, the quality of commercial honeys varies greatly depending on many factors. Hence, this study was conducted to evaluate the physicochemical and antioxidant properties of Iranian commercial honeys to confirm their nutritional and economical quality. Methods: Fifty three honey samples from six different types, including alfalfa, milkvetch, lotus, thyme, coriander and multifloral honeys, were analyzed for pH, free acidity, electrical conductivity, Ash, moisture, hydroxymethylfurfural, reducing sugars, glucose, fructose, proline, color, total phenolic content, ferric reducing antioxidant power and DPPH radical-scavenging activity. Results: : In total, physicochemical properties of different honey types were in the range of 4.3 ± 0.49 to 5.2 ± 0.49 for pH, 13.81 ± 2.5 to 26.22 ± 2.8 for free acidity (meq/kg), 15.95 ± 0.45 to 17.98 ± 0.97 for moisture (%), 282.2 ± 50.3 to 578 ± 47 for electrical conductivity (µS/cm), 0.14 ± 0.04 to 0.38 ± 0.03 for ash (g/100 g), 68.66 ± 4.3 to 72.09 ± 6.4 for reducing sugars (g/100 g), 34.67 ± 2.6 to 36.7 ± 2.2 for glucose (g/100 g), 31.9 ± 4.75 to 37.04 ± 4.0 for fructose (g/100 g), 6.1 ± 5.8 to 22.85 ± 10.9 for hydroxymethylfurfural (mg/kg), 426.7 ± 53.91 to 593.9 ± 108.6 for proline (mg/kg), 46.27 ± 4.3 to 96.04 ± 14.4 for color (mm) and 245.4 ± 48.45 to 573.9 ± 69.3 for total phenolic (mg/kg) content. In terms of antioxidant capacity, lotus and thyme honeys were preferable, while the highest level of DPPH radical scavenging activity and ferric reducing antioxidant power were observed in lotus and thyme honeys. Conclusion: These results confirmed that the Iranian commercial honeys meet the quality standards established by national and international regulatory agencies.

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