Complex sentence: The Kollatt Vaidyans maintained a family medical chronicle comprising of several volumes of palm-leaf manuscripts in Kolezhuthu script Malayalam, in which were recorded names of medicinal plants, methods of preparation and application of drugs and the illnesses for which they were used.
Split into simpler sentences: The Kollatt Vaidyans maintained a family medical chronicle comprising of several volumes of palm-leaf manuscripts in Malayalam "Kolezhuthu" script. In these manuscripts were recorded names of medicinal plants, methods of preparation and application of drugs and the illnesses for which they were used.