Ethnopharmacological relevance: Calotropis gigantiea (L.) R. Br (Apocynaceae) commonly called as "crown flower" or "giant milk weed" is a well-known weed to many cultures for treating various disorders related to central nervous system, skin diseases, digestive system, respiratory system, reproductive system etc. Indigenous groups made the plant as a part of their lives since they use the fruit fibre to make ropes, household items, for weaving clothes and flowers for garlands apart from usage for various indications. The study aims at far-reaching review on phytochemistry, pharmacological activities, ethnopharmacology, intellectual property transfer on pharmacological therapies, toxicity which aids to provide scientific evidence for the ethnobotanical claims and to identify gaps required to be conducted as a future research prerequisite.

Materials and methods: A systematic literature search was performed using different databases such as Scopus, Science direct, PubMed and Sciverse with no timeline limit set during the search. All the available abstracts and full text articles were included in the systematic review.

Results: Most of the folkloric uses were validated by the scientific studies such as analgesic, anti-arthritic, anti-asthmatic, anti-bacterial, anti-convulsant, anti-pyretic, central nervous system disorders, contraceptive, anti-ulcer and wound healing. In addition other studies such as anti-diabetic, anti-diarrhoeal, anti-helminthic, anti-histamine, anti-inflammatory, anti-microbial, anti-oxidant, cardio-protective studies, cytotoxicity, hepatoprotectivity, fibrinolytic, mosquitocidal, nerve muscle activity, vasodilation and skeletal muscle activities were also reported for the plant. Isolated compounds such as calotropin, frugoside and 4'-O-β-D-glucopyranosyl frugoside were tested for the cytotoxicity efficacy against both human and rat cell lines out of which calotropin showed potent activity (IC50-15 ng/ml). However there were no clinical trials reported on the plant which is one of the major lacunas.

Conclusions: This review article explores the ethnopharmacological, pharmacological activities phytochemistry and intellectual rights of Cg which gives the evidence of a potent and commercial drug which up on further research leads to the most viable drug for variety of treatments. However there is further need for in-vivo studies and clinical trials on isolated phytoconstituents which will help to commercialise.