Effect of extraction time on antioxidant properties of Fragrea acuminatissima

There are many plants in Malaysia that have not been exploited for their benefits which can be used in food, cosmetic and pharmaceutical industries. Fragrea acuminatissima or well known as tengkuk biawak has been claimed to have healing properties by indigeneous people. This study was conducted to find out the effect of extraction time using decoction and maceration on the antioxidant properties of Fragrea acuminatissima Merr. stem. The stems of tengkuk biawak was obtained from Gua Musang, Kelantan and dried for 2 weeks at 45 ⁰C. The stems were grinded and decocted for 5 minutes, 15 minutes, 30 minutes and 1 hour and macerated for 16 hours before the liquid extract was spray dried. Five analysis namely Total Phenolic Content (TPC), Total Flavanoid Content (TFC). DPPH assay, FRAP assay and ABTS assay was done. The result has shown that 1 hour is the best extraction time since it has the highest phenolic and flavonoid content of 216.19±17.55 µg GAE/mg and 892.11±22.19 µg QE/mg respectively. They have also exhibited high scavenging effect on DPPH radical at 400 µg/ ml and ABTS cation with 89.83 ± 0.39 % and 95.65±0.59 % respectively. The EC₅₀ value of 1 hour extract was 91 µg/ml over DPPH radical which was the second effective after 5 minutes extract. ABTS cation scavenging assay showed that there was no significant difference between extracts extracted at different duration at P < 0.05. Next, their FRAP value has also indicated considerably high value of 96.28 ± 0.7 µg TE/ mg for 1 hour extract
with no significant difference with 5 minutes extract with highest FRAP value. There was moderate negative correlation between DPPH radical scavenging activity and Total Flavanoid Content. Hence, the optimum extraction time can be applied for further study of the plant.