Phytochemical Constituent’s Comparison Using Various Drying Effects on Rubus Fraxinifolius Pour Leaves

Abstract

Rubus fraxinifolius is a genus that belongs to the Rosaceae family, which grows in the mountainous forests in Indonesia. The study aimed to determine the effects of air-drying (AD) and oven drying (OD) of the young R. fraxinifolius leaves and compare them to the fresh leaves (FL) to observe the phytochemical content and bioactivities. Phytochemical contents of the samples were determined based on qualitative assay, total phenolics, and total flavonoid, whereas bioactivities were evaluated on antioxidant DPPH free radical scavenging effect, α-glucosidase inhibitory activity, and antibacterial assays. LCMS-MS was used for the quantitative investigation of naturally occurring phytochemicals. The methanol exttract of FL had the highest free radical scavenging activity against DPPH with IC50of 45.51± 5.03µg/mL, total phenolic content (25.35 ± 1.06 mg GAE/100 mg extract), and total flavonoid content (28.71 ± 2.07 equivalent quercetin mg/ 100 mg extract) compared to those of AD and OD. However, AD had the highest α-glucosidase inhibitory activity (IC50= 8.86 ± 1.41µg/mL) among others. The antibacterial activity of the young leaves showed that there was no activity difference in both fresh and dried conditions. Based on LCMS-MS analysis, it was revealed that Luteolin-7-O-glucoronide, an active antioxidant flavonoid glycoside, had been detected in FL and AD leaf extracts, but it was not found in OD leaf extract. Our findings showed that drying could influence the phytochemical contents, which significantly affect the production of characteristic active compounds in R. fraxinifolius leaves.