Phytochemical and antifungal properties of garlic (Allium sativum) and ginger (Zingiber officinale) on three fungi isolated from sorghum sold in Bida, Niger State, Nigeria

Abstract

Fungi grow in grains and seeds during storage and hence cause spoilage of grains. Sorghum grain is the fifth major staple cereal after wheat, rice, maize and barley. It is cultivated in warmer climates and is an important food crop in semi-arid tropical areas of Africa, Asia and Central America. Sorghum is mostly grown for fodder and human food in Nigeria. The objectives of this present study include the determination of phytochemical constituents of Allium sativum and Zingiber officinale and determination of minimum inhibitory concentration (MIC) of Allium sativum and Zingiber officinale extracts against fungal isolates from sorghum commonly stored in Bida, Niger state. Extract of Zingiber officinale were found to contain alkaloids, tannins, saponins, flavonoids, glycosides and terpenoids while alkaloids, saponins, glycosides and steroids were present in Allium sativum. Stored sorghum used in this study contains, Fusarium solani, Aspergilus terreus and Fusarium oxysporum. Alium sativum and Zingiber officinale exhibited antifungal activity against the test fungi. The minimum inhibitory concentration of the extracts ranged between 30mg/ml and 50mg/ml. Synthetic fungicides can be used in the preservation of stored grains; however as a result of long-term effects on human health, natural plant extracts may be a better alternative. The effect of Allium sativum and Zingiber officinale on the fungi used in this study suggests that the spices could be useful as sources of chemotherapeutic agents against fungal infection and preservative against fungal spoilage of sorghum grain.