Extraction of antioxidant, phenolic content and minerals of coleus blumei leaves by boiling

摘要

Coleus leaves are commonly known as ati-ati leaves in Malaysia. Previous study has shown that the Coleus leaves have high antioxidant activity and nutritional value. The present work is to investigate whether antioxidant, minerals and phenolic content can be extracted by boiling the leaves in water. The antioxidant was determined by mixing the extract solution with DPPH (2, 2-Diphenyl-1-Picrylhydrazyl) solution using different ratios. Acid ascorbic acid was used as standard in measurement by Uv-Vis Spectrophotometer. Phenolic content was measured by Uv-Vis Spectrophotometer using Gallic acid as standard. There is about 40.77 wt % of antioxidant activity, 6.256998 wt% of total phenolic content, and some minerals (magnesium, calcium, iron and zinc) existing in solution after the Coleus blumei leaves were removed. The wt% of the phenolic content is directly proportional to the wt% of antioxidant activity. The mineral concentration, antioxidant activity and phenolic content seemed to be highly correlated. As a conclusion, it is proven that the Coleus blumei leaves have high potential value for the nutritional purpose.