Physicochemical and fungistatic properties of Hibiscus sabdariffa seed oil extract on Aspergillus niger in soft rot of Dioscorea alata

Abstract

Hibiscus sabdariffa, commonly known as zobo in Nigeria is an annual plant in the family Malvaceae. It is used in the production of blast fiber and as an  infusion (herbal tea). All over the world, there is an increased interest in the use of oils of plant origin as Plant Protectants and in Organic farming.  Extraction of oil from the seed of H. sabdariffa, determination of the physicochemical attributes of this oil as well as the determination of the proximate  composition of this seed were all determined using AOAC methods.The antimycotic potential of the extracted oil was investigated on Aspergillus niger  using growth studies. Results from the analysis of the seed oil showed it has a saponification value of 191.30 MgKOH/Kg, iodine value of 143.60 Wij’s,  peroxide value of 0.21Meq/Kg and specific gravity of 0.9191g. The results for the proximate composition of the seed showed that it contains 20.20% fat,  24.82% protein, 33.52% carbohydrate, 2.40% ash, 7.32% moisture and 9.88% fibre, The seed oil showed considerable fungistatic properties throughout  the experiment by significantly (P˂0.05) inhibiting the growth of this A. niger from between 100% to 63.5% for the first 5days and the last 5days respectively. H. sabdariffa seed has a high nutritional value. The result from the present study suggests that this oil has some bioactive compounds that  are fungistatic in their mode of action. These findings might pave way for the use of this seed as an alternative nutrient source and for industrial uses,  while the oil from the seed may find use as a plant protection com