脂肪細胞を対象としたインドネシア薬用植物の抗肥満研究

Obesity has become a global health problem due to its association with major life-threatening diseases including cardiovascular diseases, type 2 diabetes and numerous cancers. Over the past decades, only few anti-obesity drugs have been developed and approved. In fact, some drugs have been withdrawn from the market due to their serious side-effects. With the alarming rise of obese individuals globally and in view of the dissatisfactions with synthetic drugs, there is a growing shift towards natural product-based medications. In this study, investigation of potential anti-obesogenic agents was conducted from Indonesian medicinal plants. Indonesia, a Southeast Asian country, is rich in flora diversity which have been used as herbal medicines. Two plants, Eurycoma longifolia and Brucea javanica (both from family Simaroubaceae) were investigated for their lipolytic activity, a bioactivity to break down triglyceride into glycerol in adipocytes. Several lipolytic compounds were isolated from these plants and were further studied for their cellular mechanisms of actions. In addition, an anti-obesogenic screening was conducted to explore different mode of action from Indonesian medicinal plants. 1. Study of lipolytic activity from E. longifolia The roots extract of E. longifolia have been widely used as aphrodisiac in Southeast Asian traditional medicine. Our previous study demonstrated its activity to reduce lipid accumulation in 3T3-L1 white adipocytes without cytotoxicity, indicating an antiobesogenic activity. In current study, further investigation on lipolytic activity from this plant was conducted, including isolation of its active compounds, and lipolytic mechanisms for its extract and active compounds. Additionally, explorative study on the bioactivities of the active compounds in brown adipocytes, different type of adipocytes known for its thermogenesis, was studied. Based on glycerol release assay, the extract of E. longifolia (EL) exerted lipolytic activity in 3T3-L1 adipocytes in a concentration-dependent manner. Subsequent molecular mechanistic study using several specific inhibitors to lipolytic signaling pathways showed that PKA and ERK inhibitors attenuate the lipolytic activity of EL. Further immunoblotting analysis confirmed that EL activates PKA and ERK phosphorylation by 200% and 250%, respectively. Based on bioassay-guided fractionation, two lipolytic compounds, eurycomanone (1) and 13β,21-epoxyeurycomanone (2), were isolated from E. longifolia. Compound 1 enhanced lipolysis in adipocytes with an EC50 of 14.6 μM, while its epoxy derivate, compound 2, had a stronger activity with an EC50 of 8.6 μM. Molecular mechanistic study found that PKA inhibitor totally diminishes the lipolytic activity of 1 and 2. Furthermore, immunoblotting analysis confirmed the activation of phosphorylated PKA by both 1 and 2. When tested in WT-1 brown adipocytes, compounds 1 and 2 also reduced lipid accumulation and exerted lipolytic activity, suggesting a potential of thermogenesis stimulation. 2. Lipolytic activity of B. javanica The fruit of B. javanica has been used by local Indonesian people in traditional medicine for the treatment of dysentery, malaria, and cancers. So far, there was not much research that studies its activity in glucose and lipid metabolisms. This is the first study to explore potential anti-obesity activity from B. javanica. In this study, B. javanica demonstrated strong lipolytic activity in white adipocytes, thus further study was conducted to identify its lipolytic compounds. Bioassay-guided fractionation from B. javanica has isolated several lipolytic compounds, including brucein A (5), brusatol (6), brucenatinol (7), brucein B (8), 3’-hydroybrucein A (9), and bruceine C (10). Some isolated compounds from this plant have demonstrated much stronger lipolytic activity compared to two isolated compounds from E. longifolia. 3. Anti-obesogenic screening of Indonesian medicinal plants The 76 selected Indonesian plant extracts were subjected to two bioassays, namely lipid accumulation and glycerol release assays. The results of this screening revealed plant species that exert different lipid metabolism regulatory effects in adipocytes. There are plants that reduce lipid accumulation and enhance lipolysis, B. javanica, Melaleuca leucadendra, Zingiber purpureum, and Clerodendrum serratum. There are some plants that enhance lipolysis but not reduce lipid accumulation, Leucas lavandulifolia, Mentha arvensis, Pimpinella anisum, E. longifolia, Piper crocatum, Guazuma ulmifolia, and Sapindus rarak. There is also a plant that reduces lipid accumulation but not enhance lipoysis, Momordica charantia. Taken together, the findings of this study provide significant contributions to the body of knowledge in anti-obesity research from Indonesian medicinal plants. Not only has this study provided scientific basis and rationale for the use of those potential plants for medicinal purposes, but it has also provided information on different mode of anti-obesity effects to address this global health problem

Uncovering potential of Indonesian medicinal plants on glucose uptake enhancement and lipid suppression in 3T3-L1 adipocytes

Ethnopharmacological relevance : As obesity is a key factor in the development of type 2 diabetes, lowering lipid accumulation in adipose tissues is as important as increasing insulin sensitivity in diabetic patients. The selected plant extracts used in this screen have been traditionally used in Indonesian medicine for the treatment of diabetes and its complications. Aim of the study : To investigate of the selected plants to both increase insulin sensitivity through the enhancement of glucose uptake after insulin induction in adipocytes and suppress lipid production in the same target cells. Materials and methods : Dried Indonesian medicinal plants were extracted with 50% (v/v) aq. Methanol. The extracts were dissolved in 50% DMSO when tested on 3T3-L1 adipocytes. The screening platform consists of insulin-induced glucose uptake, lipid accumulation, and cell viability. Initially, an enzymatic fluorescence assay was designed to demonstrate the enhancement of 2-deoxyglucose (2-DG) uptake after insulin induction. Different concentrations of the extracts that enhanced glucose uptake were subjected to lipid accumulation assay using Oil Red O staining. Potential extracts based on lipid suppression were subsequently assessed by CCK-8 cell viability assay to distinguish lipid reduction activity from cytotoxicity. Results : Out of 59 plants, 13 plants demonstrated their ability to increase glucose uptake in 3T3-L1 adipocytes after insulin induction, and 4 of these plants’ extracts suppressed lipid production of the cells. The CCK-8 assay results of those 4 plant extracts suggest that the inhibition activity of Eurycoma longifolia Jack (root) and Piper nigrum L.(fruits) extracts is not attributed to their cytotoxicity in the adipose cells. Both of the plant extracts increased glucose uptake by more than 200% at 50 g/mL and suppressed lipid accumulation in a concentration-dependent manner. Conclusions : Screening of selected Indonesian medicinal plants has uncovered the potentials of Eurycoma longifolia Jack (root) and Piper nigrum L. (fruits) with dual active functions, increasing insulin sensitivity through the enhancement of glucose uptake and reducing lipid accumulation in adipose cells. These findings suggest that the ability of both plants to suppress lipid production would provide additional benefits in the treatment of diabetes

Quassinoids in Brucea javanica are potent stimulators of lipolysis in adipocytes

Obesity is associated with a number of metabolic disorders. Lipolysis is the initial step in the metabolism of lipids stored in adipocytes and is therefore considered a therapeutic target for obesity. Quassinoids are unique terpenes found in plants of the Simaroubaceae family, which were recently reported to have lipolytic activity and to suppress weight gain. Brucea javanica is a plant employed in traditional medicines in Asia, which is known to contain various quassinoids. Here, we investigated the lipolytic activity of B. javanica extracts, and identified six quassinoids: brucein A, brucein B, brucein C, 3′-hydroxybrucein A, brusatol, and bruceantinol, which represent the bioactive principals. The quassinoids contained in B. javanica demonstrated lipolytic activity at nanomolar concentrations, which were an order of magnitude lower than those of the previously reported quassinoids, suggesting that they may be useful for the treatment of obesity

Isolation and lipolytic activity of eurycomanone and its epoxy derivative from Eurycoma longifolia

Eurycomanone (1) and 13β,21-epoxyeurycomanone (2) were isolated from Eurycoma longifolia for studies of lipolytic activity. Compound 1 enhanced lipolysis in adipocytes with an EC₅₀ of 14.6μM, while its epoxy derivate, compound 2, had a stronger activity with an EC₅₀ of 8.6μM. Based on molecular mechanistic study using several specific inhibitors to lipolytic signaling pathways, it was found that PKA inhibitor totally diminished the lipolytic activity of 1 and 2. Further immunoblotting analysis confirmed the activation of phosphorylated PKA by both 1 and 2. With the growing need to develop new anti-obesity agents, eurycomanone and its epoxy derivate can be used as promising lead compounds to target lipid catabolism

Municipal solid waste management – using market instruments: applying a co-benefit approach in green economy paradigm for Indonesia

In recent years Indonesia has been confronted with an excessive generation of municipal solid waste (MSW), predominantly present in the form of organic refuse. While moving towards integrated solid waste management (ISWM) is an important strategy used to control its generation, it is also now recognized that economic approaches need to be promoted as well in order to tackle the problem concertedly. In this case study, empirical approaches are developed to understand how market instruments could be introduced into environmental services and how to apply co-benefit approach in a green economy paradigm for Indonesia. We investigate the feasibility of introducing market instruments in Indonesia by appliying local co-benefit initiatives adapted from German experiences in integrating market instruments into MSW management practices. Currently co-benefit activities are undertaken in the Sukunan village (Yogjakarta) to promote waste composting using market incentives in the framework of community-based solid waste management (CBSWM). This scheme aims at reducing MSW generation at its source and mobilizing people to be involved in waste separation (organic and non-organic) at household levels. As a result, about 200,000 t of CO2 emissions could be successfully reduced annually. By integrating market instruments into waste management practices, the result of our studies sugggests that Indonesia could make positive changes to its environmental policy and regulation of MSW at local levels. The country's policymakers have played important roles in promoting the effectiveness of urban development with co-benefits approaches to facilitate its transition towards a green eccnomy