General Toxicity screening of Royleanone derivatives using an Artemia salina model

Cancer is the second leading cause of death globally. World Health Organization recorded an estimated 9.6 million deaths attributed to cancer in 2018. There is an urgent need for new anticancer drugs with novel modes of action. Natural products remain a valuable source for the identification and development of novel treatment options for cancer. Plectranthus species are well-known medicinal species used extensively for the treatment of different illnesses. These species are rich in diterpenoids which are reported to be responsible for various pharmacological activities including cytotoxic activities. Brine shrimp (Artemia salina) is broadly used in lethality studies and this model is a convenient starting point for cytotoxicity study when screening for general toxicity of natural products. This assay is based on their ability to kill a laboratory cultured nauplii. In this work, we report the general toxicity of some derivatives from 6,7-dehydroroyleanone (1) and 7α-acetoxy-6β-hydroxyroyleanone (2) compounds. The A. salina bioassay is a simple, rapid, and low-cost test, and is very useful for preliminary assessment of general toxicity in natural products thereby guiding the determination of possible biological activities.