Toxicology & Pharmacology (T & P) Unit provides both diagnostic and research services. The main focus of research in the unit is on in vitro and in-vivo toxicology and reproductive toxicology on plant/herbal extracts and herbal products. The in-vitro toxicology includes the cytotoxicity assay and genetic toxicology such as Bacterial reverse mutation (AMES) and Micronucleus Assay. Other assay such as Mouse Lymphoma Assay and Comet assay will be developed in the future.
The Cytotoxicity assays are done to screen for cytotoxicity in the herbal extracts and herbal products received for research. Assessing cell membrane integrity is one of the commonest ways to measure cell viability and cytotoxic effects thus the MTT Assay which is based on alterations in plasma membrane permeability and leakage of components into the supernatant was used. This assay is to determine the inhibitory activity (IC50) of plant/herbal extracts or product using a panel of cell line and measures the reducing potential of the cell using a colorimetric reaction.
Ames test or bacteria reversed mutation assay is used to assess the mutagenic potential of plant/herbal extracts. The test uses several strains of Salmonella typhimurium that carry mutations in genes involved in histidine synthesis. In the absence of an external histidine source, the cells cannot grow to form colonies. Colony growth is resumed if a reversion of the mutation occurs, allowing the production of histidine to be resumed. Plant/herbal extracts with mutagenic properties will cause an increase in the number of revertant colonies relative to the background level.
We offer overall developmental and reproductive toxicology test to conduct safety assessments for plant/herbal extracts and products. Reproductive toxicology is part of the preclinical toxicity assessments. In our laboratory, research on reproductive toxicology is only focusing on the potential prenatal developmental toxicity effect of selected Malaysian herbal plants on the embryo and foetal development during organogenic periods until before delivery, using Sprague Dawley rat as a test system. Basically, the test system is administered by gavage on gestation days (GD) 6-20. Clinical signs of maternal toxicity, body weight gain, and food and water consumption are monitored recorded. Caesarean sections are performed on GD 21; living and dead foetuses and resorptions are recorded. Foetuses are weighed and examined for external abnormalities. Half of foetuses of each litter were cleared and stained with Alizarin red S for skeleton evaluation and head sectioning.
T & P Unit also provides diagnostic services to all government hospitals in the field of toxicology. It offers tests on routine screening and confirmation of common drug of abuse in urine in Malaysia. We are the organizers of the National Drug Quality Control Programme which have four samples in each year cycle. It is also the only laboratory in the Ministry of Health Malaysia which provides tests for determining the levels of various heavy metals in biological fluids using its Graphite Furnace Atomic Absorption Spectroscopy and Flow Injection Mercury System.
In support to the preclinical toxicology done on laboratory animals in full compliance to the Good Laboratory Practices (GLP) regulations in Institute Medical Research, we provide services in the analytical aspects of the process. We provide biochemical and hematological tests from blood and preparation of histopathology slides from the organs of the general toxicology animals.