Emergence of new diseases and development of complications in the old ones, coupled with safety, efficacy and affordability factors associated with existing medicines, have necessitated continuous quest for new remedies. Plants being a virtually unending reservoir of potential bioactive natural products hold great hope for more effective, safer and affordable therapeutic agents. In order to facilitate these studies, it is therefore desirable to publish reviews on medicinal plants. The present review is an effort to cover ethnomedicinal properties and research work done on medicinal plant, Carissa opaca (Apocynaceae), which is traditionally used for a number of purposes, including jaundice, hepatitis, rheumatism and asthma. Pharmacologically, different parts of plant have been studied for various bioactivities, such as, antioxidant, antimicrobial, anti‐cancer, anti‐diabetic, antipyretic, anti‐inflammatory, hepatoprotective and cytotoxic. Phytochemical investigations have resulted in the isolation of many natural products including terpenoids and flavonoids. As the extensive literature review suggests, C. opaca holds great promise for novel therapeutic remedies for various degenerative and pathological ailments. More rigorous, in vitro and in vivo, analyses and clinical studies are, therefore, recommended.

Objective:Carissa opaca is a medicinal plant with rich folkloric applications. The present research was conducted to explore the tyrosinase inhibitory potential of aqueous decoction (AD) and methanolic extract (ME) of roots of C. opaca and its fractions in various solvents and their phytochemical analysis.Materials and Methods:AD of the dried powdered roots of C. opaca was prepared by boiling in water. ME was prepared by cold maceration. Its fractions were obtained in solvents of increasing polarity, i.e., hexane, chloroform, ethyl acetate, n-butanol, and water. The biomass left after extraction with methanol was boiled in water to get its decoction Biomass aqueous decoction (BAD). Tyrosinase inhibitory activities of the samples were studied according to a reported method. Chemical compounds in the samples were identified by gas chromatography-mass spectrometry (GC-MS).Results:The AD, BAD, and ME and its fractions displayed remarkable tyrosinase inhibitory activity. The IC50 of AD was 23.33 μg/mL as compared to 15.80 μg/mL of the standard arbutin and that of BAD was 21.24 μg/mL. The IC50 of ME was 34.76 μg/mL while that of hexane, chloroform, ethyl acetate, n-butanolic, and aqueous fractions was 21.0, 44.73, 43.40, 27.66, and 25.06 μg/mL, respectively. The hexane fraction was thus most potent followed by aqueous fraction. By phytochemical analysis, campesterol, stigmasterol, gamma-sitosterol, alpha-amyrin, 9,19-cyclolanostan-3-ol, 24-methylene-,(3 β)-, lupeol, lup-20(29)-en-3-one, lup-20(29)-en-3-ol, acetate,(3 β)-, 2(1H) naphthalenone, 3,5,6,7,8,8a-hexahydro-4,8a-dimethyl-6-(1-methylethenyl)-, and 2,3,3-trimethyl-2-(3-methylbuta-1,3-dienyl)-6-methylenecyclohexanone were identified in the extracts by GC-MS. Other compounds included fatty acids and their esters. Some of these compounds are being first time reported here from this plant.Conclusions:The roots extracts exhibited considerable tyrosinase inhibitory activities, alluding to a possible application of the plant in cosmetic as whitening agent subject to further pharmacological studies.SUMMARY The present study aimed to explore the tyrosinase inhibitory potential of aqueous decoction and methanolic extract of roots of Carissa opaca and its fractions in various solvents and their phytochemical constituents. GCMS analysis was conducted to identify the phytochemicals. The extracts and fractions of C. opaca roots showed remarkable anti-tyrosinase activities alluding to their possible application to treat disorders related to overproduction of melanin. Abbreviations used: AD: Aqueous decoction; ME: Methanolic extract; BAD: Biomass aqueous decoction; GC-MS: Gas chromatography-mass spectrometry.