Antioxidant Activity of Usnic Acid Compound from Methanol Extract of Lichen Usnea sp.

Lichen Usnea sp. is one of the sources of natural bioactive compounds which are currently being developed as medicinal ingredients. The purpose of this study was the isolation and identification of secondary metabolites from methanol extract, toxicity test and antioxidant activity of Usnea sp. Lichen was isolated by maceration using methanol solvent, then separated by liquid-liquid partition and separation using vacuum chromatography. Based on the results of the study, NMR-1D spectral data and FTIR spectrum is the presence of functional groups showed the presence of F15 compound is usnic acid consisting of 18 carbons with 3 carbons from the C=O carbonyl group. The results of the toxicity test showed that all of them were active against Artemia salina L. shrimp larvae with LC50 values of 0.820 µg/mL (Usnea sp.), 1.030 µg/mL (n-hexane), 1.056 µg/mL (ethyl acetate), and 1.236 µg/mL (methanol extract). The results of the antioxidant activity test showed that the inhibitory activity of usnic acid isolate was very active with an IC50 value of 11.696 µg/mL. Meanwhile, methanol extracts and ethyl acetate showed antioxidant activity with IC50 values of 18.098 and 26.917 µg/mL, respectively.

Potential of Usnic Acid Compound from Lichen Genus Usnea sp. as Antidiabetic Agents.

Lichen Usnea sp. is potential as a new natural medicine. This study report isolation of secondary metabolites from lichen Usnea sp. and α-glucosidase inhibitory, which is potential as an antidiabetic agent. Lichen powder was macerated using methanol, separated using column chromatography gravity and thin-layer chromatography. The crystalline was isolated and purified by the recrystallization process for obtaining pure compound. The isolated compound was determined using FTIR and NMR spectroscopy (1H and 13C). The results showed that the isolated compound was yellow needle crystals. Based on the spectra data interpretation, it was obtained usnic acid compound with the molecular formula of C18H16O7. The α-glucosidase inhibitory activity test showed that the usnic acid had activity in inhibiting the α-glucosidase enzyme with an IC50 value of 106.78 µg/mL. The usnic acid from Usnea sp. has a very good impact on the source of natural compounds as an antidiabetic drug in the future.

Effectiveness of Green Chemical Solvent-based on Triethylammonium Methanesulfonate Ion Liquid for the OPEFB Pretreatment Process.

Many studies have explored the pretreatment of lignocellulosic biomass based on oil palm empty fruit bunch (OPEFB) which is categorized as potential biomass waste for bioethanol production. Before proceeding further to obtain bioethanol, several steps such as pretreatment to increase organic constituents are needed. The ionic liquids (ILs) were commonly investigated by many researchers for lignocellulosic pretreatment because it is easy solubilization property, non-toxic, and not harmful impacts on the environment. Therefore in this study, the hypothesis and main objective were to observe the effectiveness of triethylammonium methanesulfonate ion liquid (TMS IL) in the OPEFB lignocellulose pretreatment process. Three variations were studied to obtain optimization of the pretreatment process, such as times duration, IL composition, and temperature. Based on these results, we observed the effectiveness of the time duration for OPEFB pretreatment of 20 hours. Furthermore, it was applied to determine the optimization of IL composition and temperature showing that using 91% (1:1:10) at 120°C for 20 hours has provided good performance for the OPEFB lignocellulose pretreatment process. TMS IL has exhibited the ability to reduce hemicellulose and lignin contents to 7.35% and 17.80%, whereas cellulose was increased by 54.24%. This has the opportunity to be projected to a larger scale for bioethanol production based on OPEFB lignocellulose.