usnic acid

noun

us·nic acid ˌəs-nik-

: a yellow crystalline antibiotic C₁₈H₁₆O₇ that is obtained from various lichens (as old-man's beard)

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Usnea

usnic acid

USP

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“Usnic acid.” Merriam-Webster.com Medical Dictionary, Merriam-Webster, https://www.merriam-webster.com/medical/usnic%20acid. Accessed 31 Oct. 2025.

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