Judul: Identification of Antidiabetic Compounds in Karamunting Leaves (Melastoma malabathricum L.) with Metabolomic and Molecular Docking Approaches and Their Potential as Functional Drinks
Abstrak: Diabetes is a metabolic disease characterized by a high blood glucose level on fasting, which is above 126 mg/dL. Type-2 diabetes mellitus (T2D) was dominant (90%) among three types of diabetes (type-1 diabetes mellitus, type-2 diabetes mellitus, and gestational diabetes mellitus). Hyperglycemic conditions characterize the T2D traits as the result of abnormalities in insulin secretion and activity. These conditions may trigger the accumulation of free radicals. Therefore, consuming food with antihyperglycemic and antioxidant therapies might be a recommendation for DT2 patients’ treatments. Handling of DT2 sufferers can be done by consuming foods that contain antihyperglycemic and antioxidants, including karamunting (M. malabathricum) leaves which the people of West Kalimantan have often used as herbal tea given to diabetics, which is brewed with hot water. One of the taste described by the community from the brewed water of karamunting leaves (ASDK) is astringency. Previous studies have proven the antidiabetic activity of karamunting leaves by in vivo testing of ethanol and methanol extracts. Chemical compounds that act as antidiabetic, their application in diabetic animal models, and the sensory profile of the karamunting leaves, especially when consumed in brewing water, have not been reported. This study has the general objectives of identifying bioactive antidiabetic compounds with the metabolomic method, knowing the mechanism of antidiabetic in vivo using diabetic animal models, and evaluating the effect of various forms of brewing karamunting leaves (Melastoma malabathricum) on sensory profiles by analyzing multivariate (sensometric) data and their antidiabetic activity. The study was divided into three steps as follows: 1) Obtaining an LC-MS/ MS-based fingerprint profile from water extract of karamunting leaves, identifying antidiabetic bioactive compounds (antihyperglycemic and antioxidant) from brewed water of karamantung leaves with a metabolomic approach based on LC-MS/MS and molecular docking methods, and determining the best brewing conditions for karamunting leaves, and; 2) Studying the mechanism of ASDK antidiabetic activity with diabetic animal models; and: 3) Identifying and mapping the ASDK based on their sensory attributes using the sensometric method. Our study was initiated by analyzing the fingerprint profile based on LC-MS/MS, antioxidant activity (DPPH), and toxicity (brine shrimp lethality test / BSLT) of the water extract of karamunting leaves at various extraction conditions with water temperature (room temperature and hot temperature at room temperature). 90 ± 2 ºC) and different times (15, 30, 45 minutes). Six compounds namely, 4-O-caffeoylquinic acid, quercimeritin, digiprolactone, 3-O-trans-couma-roylquinic acid, norbergenin, and arteamisinine I were identified in the aqueous extract of karamunting leaves. Karamunting leaf water extract with hot water (90 ± 2 ºC) at a low dry leave:water ratio (5:100 w/v) for 15 minutes has high antioxidant activity and low toxicity. Therefore, brewing with hot water and a brewing time of under 15 minutes, i.e., 5 minutes, was used for further experiments. Furthermore, the LC-MS/MS profiles of the ASDK obtained from twelve different brewing conditions (with or without ultrasonication; dry leave:water ratio of 20:100, 7:100, and 3:100 (w/v); brewing times of 5 and 15 minutes) were used as variables in the identification stage of antidiabetic compounds. (antihyperglycemic and antioxi-dant) with a metabolomic approach. The antihyperglycemic activity was carried out in vivo
Keyword: antioxidant, antihyperglycemic, brewed water of karamunting leaf, hot brew, sensometrics