Phytochemical screening, total phenolic content, antioxidant activities and cytotoxicity of Dendrobium signatum leaves

Abstract

In the present work, the leaves of Dendrobium signatum were extracted with ethanol by maceration; called M; and by sonication-maceration for 30 and 45 mins; called MS30 and MS45. Some biological activities of extracts were investigated. The results showed that the sonication for 30 mins and then maceration 72 hr gave the highest yield at 7.32%. The phytochemical investigation revealed that the bioactive compound from M, MS30 and MS45 were similar which composed of carbohydrates, coumarins, alkaloids, flavonoids, phenolics, sterols and glycosides, respectively. The total phenolic contents were assessed by Folin - Ciocalteau method using gallic acid as the chemical standards. The results showed that MS30 displayed the highest total phenolic contents at the value of 8.83 gGAE/100 g extract. The antioxidant activity was measured using DPPH assay. The results showed that MS30 had the stronger free radical scavenging activity than M and MS45 and had moderate radical scavenging ability compared to ascorbic acid. The cytotoxicity was performed against human cancer cell lines using MTT assay. The results showed that all ethanol extracts displayed weak anticancer activity against MCF-7 and NCI-H187 cell lines, compared to the standard drug doxorubicin. In addition, they showed no activity against KB cell lines.