Melanin synthesis inhibitory activity was determined by a paper-disc agar diffusion method using the inhibition of
melanin production in Streptomyces bikiniensis. A preserved culture of S. bikiniensis NRRL B-1049 was inoculated on
a Papavizas’ VDYA agar slant. After incubation at 28 °C for 2 weeks, the spore mass formed on the aerial mycelium was
scraped with an inoculating loop. The spore suspension of S. bikiniensis was inoculated on an agar medium ISP No.7. After drying of the agar surface, a paper disc (8 mm) soaked with sample solution was placed on the agar plate. The plate
was incubated at 28 °C for 48 h and the resulting zone of inhibition of melanin formation was measured from the reverse
side of the plate.