Abstract Kebar grass (Biophytum petersianum) is traditionally believed as a food ingredient to increase the health of the reproductive. The specific bioactive compounds with antioxidant effect in this plant have not been reported before. The objective of this research was to identify the specific bioactive compounds as a source of functional food ingredients of Kebar grass (KG) which have antioxidant activity by using a metabolomic approach. Samples chemical profile (extract and fraction) used HPLC, followed by metabolomic analysis by OPLS. Chosen samples were isolated by TLC and then identified by UHPLC-MS/MS. Specific bioactive compounds were identified from chromatogram with putative identification by MZmine referring to online databases. The metabolomic result obtained ethyl acetate fraction (FEA) as the sample that most contributed to antioxidant activity. FEA identification result showed ten specific bioactive compounds that are thought to contribute to antioxidant agents. Two of the compounds were identified as caffeic acid and cassiaoccidentalin A, while the other eight compounds have not been identified. The finding of cassiaoccidentalin A in KG is a novel finding and can be used as a specific marker for petersianum species of Biophytum genus and as a source of functional food ingredients as antioxidant agents to improve reproductive health.

Abstract Melastoma malabathricum is one of the medicinal plants plated in West Kalimantan, Indonesia. Its leaves extraction using organic solvents revealed bioactive compounds and antioxidant activity. However, the antioxidant activity, toxicity, and chemical profile of water extract of M. malabathricum leaves are still unknown. This study aimed to determine extraction conditions that provide water extract of M. malabathricum with the highest antioxidant activity and the lowest toxicity. The extraction conditions were conducted at different water temperatures (25 ± 2 ºC and 90 ± 2 ºC), concentrations (10 and 5 g leaves/100 mL water), and extraction time (15, 30, and 45 minutes). Data analysis was performed by one-way ANOVA followed by Duncan's test (p < 0.05). The result showed that M. malabathricum leaves of 5g/100 mL extracted with hot water (90 ± 2 ºC) for 15 minutes showed the highest antioxidant activity (IC50 2.13 ± 19.20 ppm), which was higher than vitamin C (IC50 4.32 ± 0.16 ppm), and low toxicity (LC50 333.06 ± 99.45 ppm). Six compounds namely, 4-O-caffeoylquinic acid, quercimeritin, digiprolactone, 3-O-trans-coumaroylquinic acid, norbergenin, and arteamisinin were identified for the first time in the water extract of M. malabathricum leaves. These compounds, individually or extracted from other ingredients, have previously been reported to have antioxidant activity.

Abstract Characteristics of water-soluble flours from soy (SF), soy tempe (STF), and germinated-soy tempe (GTF) were compared with those of commercial soy protein isolate (SPI). Defatted flour of soy, soy tempe, and germinated soy tempe were extracted in alkaline water (pH 9) and freeze dried to produce water-soluble flours. Protein contents of SF, STF, and GTF were 49%, 47%, and 51%, respectively, and lower than that of SPI (84%). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) profiles showed that STF and GTF contained lower molecular size of proteins compared to SF and SPI. Trypsin inhibitor activity was detected only in SPI. The most abundant phytic acid was contained in SF, followed in order of decreasing abundance, by SPI, STF, and GTF. Antiradical activities measured by DPPH assay also showed significant variations, and the activity was highest in GTF, followed in order of decreasing activities, by STF, SF, and SPI. The foaming and emulsion capacities of STF and GTF were significantly lower than SPI, but higher than SF. These data strongly suggest that STF and GTF have better functional characteristics than commercial SPI. However, optimization of the extraction process is needed to improve the yield and protein content.