Benzothiazoles are also present in many biologically important naturally occurring products (Fig. ). Unsubstituted benzothiazole itself was first isolated in 1967 from the volatiles of American cranberries Vaccinium macrocarpon Ait. var. Early Black. Since then, benzothiazole has been isolated from many different sources: the tail-gland of the red deer Cervus elaphus, French oak wood, the fungi Aspergillus clavatus, some tealeaves and wines, etc. . Hu and MacMillan reported the isolation of erythrazoles A and B from mangrove sediments of Erythrobacter sp. The erythrazole B had been investigated to possess potent cytotoxic activity against a panel of non-small cell lung cancer (NSCLC) cell lines. 6-Hydroxybenzothiazole-5-acetic acid, also known as antibiotic C304A, is a naturally occurring benzothiazole that was isolated from the cultured filtrate of the bacterium Actinosynnema sp. and Paecilomyces lilacinus. The rifamycins are a group of antibiotics (mycobacteria) that are synthesized naturally by the bacterium Nocardia mediterranei, and are therefore used to treat tuberculosis, leprosy, and Mycobacterium avium complex infections. Violatinctamine, bright orange alkaloid isolated in 2004 from a Kenyan marine tunicate of the genus Cystodytes cf. violatinctus, presents a unique heterocyclic skeleton that combines a benzothiazole core and a dihydroisoquinoline unit. It is interesting to note that the amino acid cysteine could be the source of the sulfur atom in all benzothiazole natural products .