Simona Kranjc Brezar

1 Introduction Vitamin A (VitA), synonymous with all-trans retinol, comprises a group of derivatives known as retinoids—collectively classified as isoprenoids, that have similar properties to all-trans retinol [1, 2]. These retinoids are essential nutrients that humans must obtain from the diet, as endogenous synthesis is not possible [2-4]. Although retinol itself is not biologically active, its metabolite, retinoic acid, is the form that can modulate the activity of transcription factors [5, 6].

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Introduction In ancient medicine, Chinese and Indian cultures widely used cannabis (derived from the plant Cannabis sativa L., mostly known as “marijuana”) for the treatment of various ailments (1). In the 1850s, cannabis was introduced into Western medicine by William B. O’Shaughnessy and Jacques-Joseph Moreau, who described its beneficial effects in treating rheumatism, convulsions, muscular spasms during tetanus and rabies, mental illnesses and cholera (2, 3).