Endophytes are an endosymbiotic group of microorganisms that colonize in plants and microbes that can be readily isolated from any microbial or plant growth medium. They act as reservoirs of novel bioactive secondary metabolites, such as alkaloids, phenolic acids, quinones, steroids, saponins, tannins, and terpenoids that serve as a potential candidate for antimicrobial, anti-insect, anticancer and many more properties. While plant sources are being extensively explored for new chemical entities for therapeutic purposes, endophytic microbes also constitute an important source for drug discovery. This review aims to comprehend the contribution and uses of endophytes as an impending source of drugs against various forms of diseases and other possible medicinal use.

Aquilaria malaccensis is a precious tropical plant reputed for its agarwood resin, which is the outcome of biochemical interaction of the plant with fungus. The present study was aimed at investigating the process of agarwood production by isolating endophytic fungus from juvenile plant, effect of stem pieces of juvenile plant on the growth of fungus, and antibacterial effect of isolated fungus and leaves. Four endophytic fungi (Alternaria, Curvularia, Rhizopus and Sterilia species) were isolated from juvenile (1-year-old) A. malaccensis plant and three fungal colonies (Penicillium, Fusarium and one putative Cladosporium species) were isolated from agarwood chips. The addition of stem pieces of juvenile A. malaccensis to the culture media (PDA) exhibited profuse and faster growth of six different fungi. The methanolic leaf extract (concentration 200 mL) showed clear inhibitory zone against Streptococcus pneumonia (15.66 mm), Escherichia coli (12.80 mm), and Shigella dysenteriae (13.66 mm). However, 100 µL of methanolic leaves extract showed inhibition of 12.66, 12.30 and 11.41 mm on S. pneumonia, E. coli and S. dysenteriae plates respectively. The study concludes that agarwood is the product of persistent interaction between endogenous fungi and the plant, which triggers at early stage of its growth and the resin production probably is visible at onset of maturity.