Our effort to find new material for anti cancer from natural resources leads us to focus on stingless bee products such as honey, bee pollen, and propolis. The products were from seven stingless bees named Homotrigona fimbriata, Heterotrigona itama, Heterotrigona bakeri, Tetragonula sarawakensis, Tetragonula testaceitarsis, Tetragonula fuscobalteata, Tetragonula laeviceps. The stingless bee products were evaluated for their cytotoxicity effect on MCF-7, HeLa and Caco-2 cancer cell lines. This is the first time to be reported that the honey, ethanol extracts of bee pollen and propolis of H. fimbriata displayed more potent cytotoxicity than other stingless bee products. By chromatography and biological activity-guided fractionation, ethanol extract of propolis from H. fimbriata was fractionated and isolated its active compound named mangiferonic acid. Mangiferonic acid showed a cytotoxicity effect with IC₅₀ values 96.76 µM in MCF-7, >110.04 µM in HeLa, and > 110.04 µM in Caco-2, respectively. These results exhibited the potential of ethanol extracts from propolis of H. fimbriata to be further developed for drug and experiments to verify the function are essential.

Syafrizal, Ramadhan R, Kusuma IW, Egra S, Shimizu K, Kanzaki M, Arung ET. 2020. Diversity and honey properties of stingless bees from meliponiculture in East and North Kalimantan, Indonesia. Biodiversitas 21: 4623-4630. Kalimantan Island in Indonesia is covered by tropical rain forests that are rich in biodiversity. Species, include a stingless bee (Trigona spp.). Recently, stingless bee beekeeping (Meliponiculture) in this region has become popular because the honey has a unique taste, a mix of sweet, sour, and bitter which is highly valued. The objective of this study was to determine the diversity of stingless bee species, the number of colonies, type of hive, and honey properties such as taste, acidity, color, phytochemicals, and radical scavenging activity or antioxidant in meliponiculture in selected areas of Eastern and Northern Kalimantan, Indonesia. The area studied included Samarinda, Balikpapan, Penajam, Bontang, Sangatta, and Tarakan. The study conducted by visiting the farmers, collecting the stingless bees species and bee products (honey, propolis, and bee pollen), pH, color and taste determination, phytochemical screening, and DPPH assay. We found 12 species, with Heterotrigona itama and Tetragonula laeviceps being the main ones cultivated by people in all research areas, except Balikpapan. We counted 111 colonies of T. laeviceps and 99 of H. itama in the meliponiculture. There were three types of hive used by farmers in meliponiculture. Most of the honey tasted sweet and sour with acidity or pH ranging from 3-4, and color from dark brown to light yellow. The phytochemicals contained tannin, alkaloid, flavonoid, triterpenoid, carotenoid, coumarin, saponin, and carbohydrate. The Tetragonula sarawakensis honey was the most potent in term radical scavengers. Our findings showed that stingless bee honey contains antioxidants with phytochemicals that are very useful for human health.

Herawati E, Ramadhan R, Ariyani F, Marjenah, Kusuma IW, Suwinarti W, Mardji D, Amirta R, Arung ET. 2021. Phytochemical screening and antioxidant activity of wild mushrooms growing in tropical regions. Biodiversitas 22: 4716-4721. This study aims to determine the presence of secondary metabolites which generally have bioactivity that is antioxidant with phytochemical tests and antioxidant tests in Auricularia auricula, Schyzophyllum commune, Microporus xanthopus, and Trametes versicolor fungi that grow in the wild. Phytochemical analysis was carried out by testing color changes and modifications, while antioxidant tests were carried out by using a UV-Vis spectrophotometer and a DPPH solution (1,1-diphenyl-2-picrylhydrazyl). This research found that edible wood fungus that grows, wild such as A. auricula, contains secondary metabolites, namely flavonoids, triterpenoids, saponins, and tannins, but does not contain steroids, alkaloids, carotenoids, or coumarin, while S. commune contains secondary metabolites, namely flavonoids, steroids, tannins, and coumarin, but does not contain triterpenoids, alkaloids, carotenoids, or saponins and non-edible wood fungus, such as M. xanthopus, contains secondary metabolites, namely, flavonoids, saponins, tannins, coumarin, and steroids, but does not contain triterpenoids, alkaloids, or carotenoids, while T. versicolor contains compounds, secondary metabolites, flavonoids, saponin, tannins, coumarin, and triterpenoids, but does not contain steroids, alkaloids, or carotenoids. The antioxidant test results are based on IC50 calculations; it is known that the IC50 value of A. auricula is 499.25 g/mL, while S. commune is 121.37 g/mL, M. xanthopus is 251.20 g/mL, and T. versicolor is 493.04 g/mL. Based on the research results, edible and inedible wood mushroom extracts contain several phytochemicals and show potential for antioxidant activity.

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.

We investigated the leaves of Kleinhovia hospita, a plant which has been traditionally used in Indonesia as phytotherapy to cure liver disease, to describe antioxidant materials from plant sources. K. hospita leaves were extracted with methanol and further partitioned into n-hexane, diethyl ether, and ethyl acetate. The antioxidant activity of each fraction and the residue was assessed using a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method and their cytotoxicity on HepG2 liver cancer cells was determined by a MTT assay. The K. hospita leaf methanol extract showed strong antioxidant activity (96%) compared with vitamin C (98%) by the DPPH method and the measured activity from the subsequent extracts of the methanol extract were 48.9% for n-hexane, 74.0% for diethyl ether, 84.3% for ethyl acetate, and 77.1% for the residue. The MTT assay showed the cytotoxicity of the methanol extract on HepG2 cells at 14%, 76%, and 80% at concentrations of 50 microg/mL, 87.5 microg/mL, and 125 microg/mL, respectively. Leaf extracts of the medicinal plant K. hospita showed potent antioxidant activity and moderate cytotoxicity on HepG2 liver cancer cells.