Carbonic anhydrases (CAs, E.C.4.2.1.1) are an important metalloenzyme family that catalyzes reversible CO2 hydration and HCO3dehydration in organisms. CA inhibitors can be used in the treatment of many diseases such as glaucoma, epilepsy, obesity, and cancer. This study aimed to determine the effects of oil and methanol extracts of Cefan melon (Cucumis melo L.) seed (CMS) on CA enzyme activity. While both extracts activated hCA-I isoenzyme, they inhibited hCA-II. In order to determine the active substance causing inhibition or activation in CMS, essential oil content, phenolic substance profile and macro-micronutrient elements were investigated. Dominant fatty acids were identified as linoleic and oleic acid, while the dominant phenolic compound was gallic acid. Besides, it was found that CMS contained high concentrations of Ca, K and Na, and was rich in Se. Results demonstrated that essential oil and phenolic compounds in Cefan melon have potential applications as alternative natural products for pharmaceutical industries. In addition, Cefan melon seed has a w ide range of applications for food and cosmetic industries based on the research into the fatty acid, phenolic content, and nutrient elements.