Antioxidant Capacity And Mineral Contents Of Five Species Of Cucurbitaceae Seeds From Cameroon

Research Article
Mercy Bih Achu Loh., Josiane Madah Silatsa and Elie Fokou
Antioxidant and antiradical activities, phenols, minerals, Cucurbitaceae, different regions

Cucurbitaceae seeds are widely used to prepare African sauces. Their proximate analysis has shown their nutritional potential as sources of macronutrients for humans. They are also used for medicinal purposes but their contents in phytochemicals and minerals that could explain their utilization are not yet investigated in Cameroonian context. This paper therefore analyses some secondary metabolites, the total antioxidant and antiradical abilities of oils, phenol and mineral contents in the seeds of Lagenaria siceraria, Cucumeropsis mannii, Cucurbita maxima, Cucurbita moschata and Cucumis sativus, from different agro-ecological zones in Cameroon. The methods of screening of phytochemicals and antioxidant evaluation have been described in detail. The mineral content was by flame absorption spectrophotometry on ash solutions except for phosphorus which was by colorimetry. The results showed that saponins, tannins, flavonoïds, alkaloids, phenols and triterpenes were present in all the seeds, except C. mannii which had no saponins. The phenol content varied from 299 (C. mannii) to 735mg Gallic Acid Equivalent (EAG) /100g dw (C. maxima). These secondary metabolites confer to them antimicrobial properties. The total antioxidant capacity ranged from 50 (C. moschata) to 97.78 mgEq.catechine /g dw (C. sativus). L. siceraria oil had the highest antiradical activity (0.083). The high antioxidant capacities of these seeds (especially C. sativus) and the abilities of their oils to trap the DPPH• radical (especially L. siceraria oil which was similar to that of Olive oil), suggest their potential use against cardiovascular diseases and prostate cancer. These seeds were rich in minerals, especially C. moschata with the highest levels of phosphorus (810.26), potassium (681.38), magnesium (586.21), sodium (2.01), iron (5.06), zinc (5.46) and manganese (2.81 mg /100g dw). The Na/K<1 and high Zn levels suggest their potential use against hypertension and enhancement of the immune system for people living with HIV/AIDS.