Nature is an indispensable source of new compounds that can be used as medicinal agents. Natural products play an invaluable role in the drug discovery process. Recently, interest in research on natural products has been renewed due to failure of alternative drug discovery methods to deliver many lead compounds in key therapeutic areas (Bramachari, 2011)
The rich biodiversity in the Philippines has always been an important source of bioactive products which could be harnessed for medical and health purposes. However, these resources should be utilized appropriately and evaluated properly in order to maximize their uses for drug development, and consequently, for disease prevention and treatment.
An important focus in drug discovery and research is cancer treatment, as cancer is one of the most prevalent diseases today. In 2012, an estimated 14.1 million adults in the world were diagnosed with the disease and 8.2 million deaths were accounted to the disease. In the Philippines, new cases of cancer reached an estimate of 98,249 while deaths were estimated at 59,012 with the risk of dying before age 75 at 9.8 percent (Globocan, 2012). Targeted therapies have been the focus in anticancer drugs in the 90s, but with the failure of these drugs to take positive actions against many solid tumors, interest in natural products has been revitalized (Basmadijian, et al., 2014).
Another important area for drug discovery and research is immunotherapy. Boosting immunity is important against environmental stress and infections due to pathogenic organisms, and in immunodeficiency conditions (e.g. HIV infection). On the other hand, immunosuppression is an essential mechanism in cases of allergies and autoimmune diseases. Immuno-inhibitory substances, or substances that block the immune system, are also useful in transplant medicine since there is still a continuous search for therapeutic agents to alleviate graft rejection (Butler, 2005). Thus, it is crucial to discover bioactive principles that can modulate immune responses.
The country’s rich collection of endemic and native plant species presents a vast ground for the discovery of unique plant-derived anticancer and immunomodulatory agents. For this reason, native and endemic plants from the Philippines are being studied further and formulated as effective drugs. The Institute of Biology of the University of the Philippines Diliman, headed by Dr. Sonia D. Jacinto and Dr. Elena Catap, with Ms. Cielo Mae Marquez, Ms. Abigail Trinidad, Ms. Anna Isabel Navarro and Mr. John Perry Morales as Research Associates, is screening Philippine terrestrial plants extracts for cytotoxic and immunomodulatory activities through in vitro cell-based assays.
Philippine indigenous and endemic plant samples were collected from various locations such as Morong and Limay, Bataan; Mt. Makiling, Los Baños, Laguna; and UP Diliman. These plant samples were air-dried for more than two weeks, then homogenized into powder form. The powdered samples were soaked in absolute ethanol with one gram sample to ten millimeter ethanol ratio. The duration of soaking should be at least 48 hours to ensure that the organic compounds from the plant extracts are released into the ethanol.
The soaked samples were then filteres to ensure that only the liquid portion of the ethanolic extract is collected. The liquid ethanolic extract is collected. The liquid ethanolic extract will then be subjected to rotary evaporation to exclude the ethanol, leaving a concentrated plant extract which is ready for various assays. These extracts are tested for their cytotoxicity against cancer cells and for their ability to stimulate or inhibit immune response in mice cells. Extracts exhibiting significant activities will be further tested with confirmatory cell-based assays. Later on, extracts with significant activities in confirmatory assays will be subsequently subjected to bioassay to isolate, purify and identify the active compounds present. From these, a library of bioactive extracts shall be generated to be used for future Adsorption, Metabolism and Toxicity (ADMETox) assays.
It is hoped that the information obtained from this study will be used by the drug industry, herbal industry, and other scientists and researchers for projects dedicated to the advancement of cancer treatment and immunotherapy.
Written by: Dr. Sonia D. Jacinto and Dr. Elena S. Catap University of the Philippines Diliman Published by: Department of Science and Technology-Science and Technology Information Institute (DOST-STII)