Antioxidant Activity and Cytotoxicity Against WiDR Cell and Vero Cell of The Karamunting (Rhonomyrtus tomentosa L.) Leaves Ethanol Extract

Karamunting (Rhodomyrtus tomentosa L.), a plant used as a traditional medicine, is widely distributed throughout Indonesia. Karamuting has the potential as an antioxidant and anticancer agents because of its phenolic and flavonoid components. This study aimed to determine total phenolic level, antioxidant activity and cytotoxic of karamunting leaves extract. The simplisia of karamunting leaves were extracted by maceration method using 96% ethanol, tested for its antioxidant activity using DPPH and its citotoxic by MTT method (3- (4,5-dimethyltiazol-2-il) -2,5-diphenyl tetrazolium bromide) on WiDr cells and Vero cells. The results of this study showed that the yield of karamunting extract were 15.635% with a total phenolic level of 0.76%, antioxidant activity (IC50 values) of 15,330 μg / mL and cytotoxicity (IC50 values) of 205.7069 μg / mL for WiDr cells and 44.87703 μg / mL for Vero cells. Ethanol extract of karamunting leaves possessed a very strong antioxidant activity while it showed a weak cytotoxic effect on WiDr cells and toxic effect on Vero cells.Keywords: Antioxidant, Anticancer, Karamunting

Study of Molecular Docking of Alkaloid Derivative Compounds from Stem Karamunting (Rhodomyrtus tomentosa)Against α-Glucosidase Enzymes

Karamunting plant (Rhodomyrtus tomentosa) is a traditional medicinal plant. The leaves, roots, stems, and fruits of Karamunting have been identified, and their biological activities are antioxidants, antibacterial, antidiabetic, anti-inflammatory, and anticancer that contained alkaloids, tannins, and flavonoids. The types of alkaloids found in karamunting stems are homolycorine, ismine, lycorine, maritidine and tazetine. This study aims to determine the binding score of alkaloid-derived compounds with protein α-glucosidase and determine the protein's active site bound to the ligand. The method used in this research is Protein-Ligand ANT-System (PLANTS). The results showed that the anchoring score of homolycorine was -60.83 kcal/mol, ismine -64.42 kcal/mol, lycorine -71.20 kcal/mol, maritidine -61.82 kcal/mol, and tazetine -65.02 kcal/mol. The active sites used for binding are Glu526, Gly555, and Pro556. The average score for anchoring alkaloid-derived compounds with protein α-glucosidase is 83.84%. This number indicates that karamunting stems can be used as antidiabetic.

Fabrication of Dye-Sensitized Solar Cells (DSSC) Using Mg-Doped ZnO as Photoanode and Extract of Rose Myrtle (Rhodomyrtus tomentosa) as Natural Dye

A dye-sensitized solar cell (DSSC) device using Mg-doped Zn thin films as photoanode and fruit extract of rose myrtle (Rhodomyrtus tomentosa) as the natural dye was investigated. The effect of annealing temperature (400-550°C) on the films of photoanode was systematically studied using an X-ray diffractometer (XRD), UV-Visible Near Infrared (UV-Vis NIR) Spectrophotometer, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). XRD confirm that all sample has the wurtzite hexagonal with crystallite size of 25 nm. The SEM images reveal particles on the surface of the Mg-doped ZnO thin film of irregular shapes. Increasing the annealing temperature leads to a larger particle size and slightly increases bandgap energy. The dye sensitizer of extracted rose myrtle (Rhodomyrtus tomentosa) has a strong absorption at the visible light region. The maximum efficiency of the DSSC device is 3.53% with Mg-ZnO photoanode annealed at 500°C.

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.

NGHIÊN CỨU TUYỂN CHỌN VÀ ĐỊNH LOẠI CHỦNG LỢI KHUẨN LÊN MEN LACTIC TỪ QUẢ SIM (Rhodomyrtus tomentosa)

Cây sim mọc tự nhiên ở hầu hết các thôn trên địa bàn xã Côn Lôn, ngoài các giống phổ biến trên địa bàn nghiên cứu thì Rhodomyrtus tomentosa hiếm gặp hơn. Ở địa phương, quả sim được sử dụng chủ yếu nhiều để ngâm rượu, ăn tươi bên cạnh các sản phẩm chế biến từ quả như mứt sim, mật sim, vang sim. Dịch ép quả sim có hàm lượng tanin, hàm lượng vitamin C cao, có ý nghĩa lớn trong kháng khuẩn. Sử dụng các phương pháp nghiên cứu đặc thù chúng tôi đã phân lập được 5 chủng lactic kí hiệu từ L1-L5. Định danh chủng L5 bằng việc giải trình tự 16S rADN của chủng kết quả thu được Lactobacillus plantarum (L. plantarum) thuộc chi Lactiplantibacillus, đặt tên chủng là: L. plantarum L5.