Abstract

The Clerodendrum serratum (Spreng.) known as ‘Timba Tasek’ is widely used in Asian countries especially Malaysia as the traditional medicine to treat various diseases. This study aimed to evaluate the antioxidant, antiangiogenic and vasorelaxant activities as well as the chemical profiles of C. serratum leaves extract. The dried powder leaves of C. serratum were extracted serially with petroleum ether, chloroform, followed by methanol and water by maceration method. To elucidate the antiangiogenic properties, the inhibitory effects of these extracts on blood vessel growth formation were adapted in rat aortic ring assay. In another set of experiments, the possible vasorelaxant activity of C. serratum leaves extracts were examined on an isolated rat aortic ring preparations and responses of cumulative doses of noradrenaline (NA) were used. To determine antioxidant activity of this plant, the present study used well-established methods, that is, 2,2’-diphenyl-1-picrylhydrazyl (DPPH^•) radical scavenging activity and trolox equivalent antioxidant capacity (TEAC) assay. The results showed that, amongst four extracts, methanolic extract of C. serratum (ME-CS) showed the most potent antioxidant, antiangiogenic and vasorelaxant activities. In another hand, qualitative study proved that ME-CS contains polyphenolics (hydrolysable tannins and flavonoids), terpenoids, saponins and may not contain any alkaloids. Therefore, while polyphenolics are the predominant compounds found in ME-CS, it is highly probable that they may play an important (dominant) role in antioxidant, antiangiogenic and vasorelaxant activity. Since all the three activities of C. serratum extracts end up in the same results, it is likely that, all the activities were contributed by same group (such as polyphenolics) or totally different group of chemical compounds that may act synergistically together with polyphenolics. Polyphenolics are responsible for antioxidant, antiangiogenic and vasorelaxant effects of plants as herbal therapy such as C. serratum leaves.

Key words: Clerodendrum serratum (Spreng.) leaves, polyphenolics, antioxidant, antiangiogenic, vasorelaxant, phytochemical analysis.