Dr Jayapal's early interest was in immunology including his doctoral studies on leprosy and he has published extensively on various diseases - TB, leprosy and autoimmune diseases. Dr Jayapal has extensive publications on the effects of antimicrobial on bacteria especially Mycobacterium tuberculosis with new developments of drugs to control multidrug resistance tuberculosis. Over these past few years, Dr Jayapal has been actively involved in vitro experiments - studying extracts of leaves of Thulsi plant (Ocicmum sanctum L.) and found that these essential oils show antibacterial activity against as many as 17 human pathogenic bacteria and M. tuberculosis. He further tested for the chemical composition of the essential oils by using the Gas Chromatogram - Mass Spectrum (GC-MS) analysis and found the presence of several chemicals including Eugenolis which displays anti-bacterial activity against about 7 human pathogenic bacteria and Mycobacterium tuberculosis. He continues his in vitro studies on new drugs to address the toxicities and synergistic effects of eugenol when combined with rifampicin or isoniazid as treatment for Mycobacterium tuberculosis. He has recently applied for a patent of his work on skin ointment to treat wounds in a shorter amount of time.