Evaluation of Antioxidant Properties and Total Phenolic Content of Selected Nigerian Spices from Rivers State

Nigerian culinary spices are rich repositories of bioactive phenolic compounds with demonstrated antioxidant potential, yet systematic comparative chemical analysis of commonly used species from specific Nigerian localities remains limited. This study evaluates the total phenolic content and antioxidant properties of six commonly used Nigerian spices: ehuru (Monodora myristica), uziza (Piper guineense), grains of Selim, calabash nutmeg, turmeric, and ginger, sourced from markets in Rivers State, South South Nigeria. Spice samples are dried, powdered, and extracted with 80 percent methanol by cold maceration. Total phenolic content is determined by the Folin-Ciocalteu colorimetric method. Antioxidant capacity is assessed using the DPPH radical scavenging assay, the ferric reducing antioxidant power assay, and the ABTS radical cation decolorisation assay. Standard curves are constructed using gallic acid and Trolox equivalents. All assays are performed in triplicate and results are expressed as means plus or minus standard deviation. Statistical differences across spice types are assessed by one-way analysis of variance and Tukey multiple comparison tests. A positive correlation between total phenolic content and antioxidant capacity is anticipated based on existing literature. Findings contribute to the valorisation of Nigerian food spices as functional food ingredients and natural antioxidant additives for the food industry. Keywords: antioxidant activity, total phenolic content, Nigerian spices, DPPH assay, functional food