Biological activity and phytochemical study of purple pigment from Gynochthodes sublanceolata Miq.

Color plays a major role affecting a consumer’s first perception towards product. Artificial food colorants were widely used by people. However, the usage of synthetic food colorants were found to cause several health problems such as cancer and hypersensitivity. Thus, this study presents new discovery of natural purple color from Gynochthodes sublanceolata, which have high potential to be developed as natural food colorant to replace synthetic colorant. Purple colored pigment (PCP) was successfully extracted and separated from pitang leaves. The objectives of this study were to provide biological activities and phytochemical profile of PCP. Biological activities of PCP were determined by DPPH free radical scavenging assays, antibacterial test by disc diffusion test, brine shrimp lethality test, sulphorhodamine B assays, and heat stability test. Phytochemical profiles of PCP was determined by anthocyanin analysis using high performance liquid chromatography, folin-ciocalteu method, aluminium chloride colorimetric method, fatty acid methyl ester, and amino acid profile. The result shows that PCP has moderate antioxidant activity with IC50 267.38 ± 2.47 µg/mL. PCP was inhibited the growth of Edwadsiella tarda, Aeromonas hydrophila, and Flavobacterium columnare. PCP was found to be non-toxic towards human cell line MCF-7, HT-29, and WRL-68 and Artemia salina with IC50 > 1.00 mg/mL and IC50 2.11 ± 0.02 mg/mL respectively. Heat stability test shows that PCP was stable after heat treatment. Anthocyanin pigments were detected in PCP and expected to contribute for purple color of pitang leaves. Total phenolic contents and total flavonoid compounds in PCP were 10.90 ± 0.25 µg GAE/mg PCP and 0.92 ± 0.02 µg CE/mg PCP respectively. PCP contained fatty acids and amino acids about 325.00 ± 21.21 mg/100 g PCP, and 1.11 ± 0.04 mg/100 mg PCP. In conclusion, PCP shows moderate antioxidant and antibacterial activities, as well as non-toxic. Heat treatment did not effects purple color faded. The main group of compound presence in PCP was phenol group, including anthocyanin, flavonoid, fatty acids and amino acids. Collectively, PCP might have potential to be developed as natural food colorant in order to replace synthetic food colorant.