The method for producing noble metal nanocomposites involves reducing noble metal ions (Ag, Au and Pt) on graphene oxide (GO) or carbon nanotubes (CNT) by using Artocarpus integer leaves extract as a reducing agent. As synthesized MNPs/GO and MNPs/CNT composites have been characterized using X-ray diffraction (XRD), transmission electron microscope (TEM) imaging, and energy dispersive X-ray spectroscopy (EDX). The TEM images of prepared materials showed that the nanocomposites were 1-30 nm in size with spherical nanoparticles embedded on the surface of GO and CNT. This synthetic route is easy and rapid for preparing a variety of nanocomposites. The method avoids use of toxic chemicals, and the prepared nanocomposites can be used for biosensor, fuel cell, and biomedical applications.