Quantification of phenolics, flavonoids and antioxidant activity of Tamarindus indica from selected areas in Tanzania

Abstract

Abstract. Mbunde M, Mdegela RH, Laswai HS, Mabiki FP. 2018. Quantification of phenolics, flavonoids and antioxidant activity of Tamarindus indica from selected areas in Tanzania. Biofarmasi J Nat Prod Biochem 16: 22-28. The objective of this study was to establish the quantities and antioxidant activity in fruits and leaves of Tamarindus indica L. collected from three agroecological zones of Tanzania represented by the Morogoro, Tanga, and Dodoma regions. Samples were examined for their total phenolic and flavonoid contents as well as their antioxidant activity. The total phenolic content showed a significant difference in all fruit and leaves extracts and ranged from 1994.4±530.77 to 17874.67±5234 mg GAE/100 g. Similarly, the total flavonoid content in tamarind leaf and fruit extracts ranged from 880±609.45 to 11483.11±2559.67 mg CE /100 g dry weight. There was a significant difference between the antioxidant activity in the leaf (54.39±0.13%) and fruit extracts (40.11±0.03%). Tamarind leaf extracts exhibited significantly higher radical scavenging activity than fruit extracts. The antioxidant activity in fruit extracts expressed in percentage ranged between 29.27±0.06% and 40.11±0.03%, while in leaf extracts, the activity ranged from 22.33±0.08% to 54.39±0.13%. The radical scavenging activity from Coastal leaf extracts had the highest activity, followed by Eastern leaf extracts and lastly, Central leaf extracts. The highest activity was shown in the fruit samples by Coastal fruit extracts, followed by Central fruit extracts, and Eastern fruit extracts were the least active. The values in the Ferric reducing power (FRAP) assay ranged between 6968±3655.91 µM Fe (II)/g and 76822.67±23259.9 µM Fe (II)/g for leaves and fruits dry mass, respectively. These values correspond to the antioxidant activity, positively correlated with the total phenolic and flavonoid contents. Geographical location and climatic conditions have been reported to have enormous effects on the amount and activity of antioxidants available in both tamarind leaves and fruits. Findings from the study indicated that tamarind could be utilized as a cheap source of antioxidants. However, more agronomic studies should be considered to confirm the effects of agroecological differences on antioxidant activity.