Phytochemical profile, in vitro bioaccessibility, and anticancer potential of golden root (Rhodiola rosea L.) extracts.

The effects of water and ethanolic (40 %, 70 %, and 96 %) extraction on the Rhodiola rosea L. phytochemical profile (HPLC analysis), stability during extract drying, potential bioaccessibility in simulated gastric and intestinal conditions, and cytotoxic activity against human colorectal adenocarcinoma cells (Caco-2 and HT-29 cell lines) were investigated. The phytochemical profile, extractability, and stability during extract processing depend on the solvent type. In general, compounds derived from dry extracts were characterized by higher bioaccessibility than those extracted from powdered plant material. In the case of salidroside, tyrosol, and rosavins, one of the highest bioaccessibilities (often about 100 %) were found for the 70 % ethanolic extract after gastric digestion. Furthermore, the 70 % ethanolic extract most effectively reduced the viability of Caco-2 cells (IC50 85.8 µg∙mL-1). The results suggest that golden root extracts, in particular 70 % ethanolic extract, seem to be promising supplements for the food industry.

Comprehensive chemical characterization and biological evaluation of two Acacia species: A. nilotica and A. ataxacantha.

The genus Acacia (Family Leguminosae) is composed of several medicinal plants used for treating miscellaneous diseases. Amid the important members of this genus, A. nilotica and A. ataxacantha are widely employed for their tremendous healing properties. Hence, this present work aimed to determine the total phenolic and flavonoid contents and investigate the antioxidant, antiproliferative, anti-enzyme and antimicrobial potentials of methanolic and water extracts of leaves and stem bark of A. nilotica and A. ataxacantha obtained by maceration and ultrasonication. The total phenolic and flavonoid contents were obtained in the range of 33.35-116.60 mg GAE/g and 0.26-49.90 mg RE/g, respectively, with the methanolic leaf extracts of both species showing the highest contents. Moreover, the methanolic extracts were observed to display higher antioxidant potentials in almost all antioxidant assays performed compared to the water extracts (ABTS: 52.66-943.81 mg TE/g, DPPH: 8.51-493.90 mg TE/g, CUPRAC: 106.39-1193.75 mg TE/g; FRAP: 31.38-416.21 mg TE/g, and phosphomolybdenum: 0.90-4.17 mM TE/g). However, the water extracts were seen to be better metal chelators than the methanolic extracts (8.47-36.85 mg EDTAE/g). Additionally, all extracts were found to exhibit anti-tyrosinase (30.79-74.80 mg KAE/g) and anti-amylase (0.10-1.10 mM ACAE/g) properties. With the exception of a few extracts, glucosidase and acetylcholinesterase inhibitions (1.69-2.12 mg ACAE/g and 0.42-2.61 mg GALAE/g, respectively) were also demonstrated. While the methanolic extracts of both species showed antimicrobial potency against all the 18 tested microorganisms (gram positive, gram negative, and fungi), the water extracts were effective only against the gram positive bacteria. The extracts were also found to exhibit antiproliferative effects on SH-SY5Y human neuroblastoma cells, with the methanolic extracts showing higher cytotoxic potential than the water extracts. Therefore, this study showed these species to be good sources of antioxidants, enzyme inhibitors, antimicrobials and antiproliferative agents, which could be of great interest for their applications as natural bioactive ingredients in the development of pharmaceuticals and nutraceuticals.