Extracts of Indonesian medicinal plants, Murraya koenigii, Syzygium polyanthum, and Zingiber purpurea were investigated for their biological activity. The presence of phytochemicals, cytotoxicity, and antimicrobial and antioxidant activities were investigated. Parts of M. koenigii, S. polyanthum, and Z. purpurea were extracted with ethanol. The extracts were evaluated for antimicrobial activity using the disc diffusion method, while antioxidant activity was determined with a 1,1-diphenyl-2-picrylhydrazyl radical scavenging assay. Cytotoxicity was investigated using the brine shrimp lethality test, and phytochemical screening was performed using a standard method. M. koenigii leaf extract exhibited the most activity in the test microorganism activity index (AI), 0.38−1.25, when compared with standard drugs. S. polyanthum ripened fruit displayed significant antioxidant activity (90%) in comparison to ascorbic acid (95%). Z. purpurea rhizome extract possessed the highest cytotoxic effect with a LC 50 of 52 μg/mL. Phytochemical analysis revealed that carbohydrate, tannin, alkaloid, steroid, triterpenoid, and flavonoid were present in the extracts of M. koenigii leaves and twigs, S. polyanthum leaves and ripened and unripe fruits, and Z. purpurea rhizome, while saponin was only present in the S. polyanthum ripened fruit extract. Our work revealed that the M. koenigii leaves, S. polyanthum ripened fruit, and Z. purpurea rhizome extracts have potential as sources of new antimicrobial, antioxidant, and cytotoxic compounds, respectively.

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An active compound from the bulb of Eleutherine americana L. Merr. (Iridaceae) collected from East Kalimantan, Indonesia, was tested for its antidermatophyte and antimelanogenesis activity. Antifungal assay-directed fractionation of the n-hexane-soluble fraction of the methanolic extract of the bulb of E. americana led to the isolation of 1 as an active compound. The compound was identified as the naphthoquinone eleutherin by EI-MS and (1)H-, (13)C-, and two-dimensional NMR analyses. Antidermatophyte assay of 1 at concentrations of 10, 20, 40, 60, and 80 microg/disk and myconazole, a commercial antidermatophyte, at 10 microg/disk displayed 7, 8, 13, 16, 17, and 14 mm of inhibition zone against Trichophyton mentagrophytes, respectively. In a melanin formation inhibition assay, compound 1 displayed potent antimelanogenesis activity at 5 ppm with low toxicity compared with arbutin, a commercial skin-whitening agent. The results showed the high potential of 1, an active compound from E. americana, to be applied as an antidermatophyte and antimelanogenesis agent.

Abstract. Nurhasnawati H, Sundu R, Sapri, Supriningrum R, Kuspradini H, Arung ET. 2019. Antioxidant activity, total phenolic and flavonoid content of several indigenous species of ferns in East Kalimantan, Indonesia. Biodiversitas 20: 576-580. This study aimed to determine the total phenolic and flavonoids content and antioxidant activity of ethanol extract of several indigenous species of ferns in East Kalimantan. Total phenolic content was determined by Folin-Ciocalteau method and flavonoid content was measured by colorimetric method. Antioxidant activity was evaluated by DPPH (2,2-diphenyl-1-picrylhydrazyl) method. The result of photochemical screening indicated that the leaves of Plagiogyria pycnophylla, Plagiogyria glauca, and Stenochlaena palustris contained alkaloid, flavonoid, tannin, saponin, and steroid while Acrostichum aureum contained flavonoid, tannin, saponin and steroid. The result showed extract Acrostichum aureum had the highest total phenolic content (366.4573 ± 2.2117 mg GAE.g-1), flavonoid content (228.6087 ± 2.2548 mg QE.g-1), and very strong antioxidant activity with IC50 value 29.5303 ppm. There is positive correlation between total phenolic content, flavonoid with antioxidant activity.