# Nanoencapsulation of Rhodiola rosea extract into 2-hydroxypropyl-β-cyclodextrin: enhanced antibacterial and anticancer activities

## TL;DR

Encapsulating Rhodiola rosea extract in cyclodextrin improves its antibacterial and anticancer effects while keeping its antioxidant properties.

## Contribution

Nanoencapsulation of Rhodiola rosea extract in HPβCD significantly enhances antibacterial and anticancer activities.

## Key findings

- RRME-ICs showed IC90 values of 2.38, 3.95, and 1.92 mg mL−1 against E. coli, P. putida, and S. aureus.
- RRME-ICs had an IC50 of 48.14 µg mL−1 against melanoma cells, compared to 131.24 µg mL−1 for the extract.
- Encapsulation preserved antioxidant activity with 92.6% scavenging efficiency in the DPPH assay.

## Abstract

The methanolic extract of Rhodiola rosea (RRME) exhibits multifaceted biological functions, notably antioxidant, anti-inflammatory, and neuroprotective potential. These properties are primarily associated with its rich therapeutic phytochemicals such as salidroside, rosavin, and tyrosol, which contribute to its potential therapeutic applications in managing stress-related disorders and neurodegenerative conditions. In this study, RRME was extracted using the Soxhlet method and subsequently encapsulated in (2-hydroxypropyl)-beta-cyclodextrin (HPβCD) using the freeze-drying technique, forming inclusion complexes (RRME-ICs). RRME-ICs were spherical morphologies with a size range of 87.36 to 166.5 nm. The ICs had a polydispersity index of 0.283 ± 0.01 and %EE of 78.88 ± 1.55%. FT-IR, 1H NMR, 2D NMR NOESY, and TGA demonstrated the effective incorporation of RRME into HPβCD and enhanced integrity with a high thermal stability up to 350 °C. RRME-ICs demonstrated strong antibacterial effects compared to the extract. The MIC90 of RRME exceeded 20 mg mL−1 against Escherichia coli, Pseudomonas putida, and Staphylococcus aureus, indicating limited antibacterial potency. Release kinetics analysis confirmed that the Korsmeyer–Peppas model provided the best fit for RRME-ICs across both pH conditions. RRME-ICs demonstrated remarkable antibacterial activity, with IC90 of 2.38, 3.95, and 1.92 mg mL−1 against E. coli, P. putida, and S. aureus, respectively. Additionally, RRME-ICs preserved antioxidant activity in the DPPH scavenging assay, demonstrating 92.6% scavenging efficiency with an IC50 value of 0.0657 mg mL−1. RRME-ICs also exhibited notable anticancer potential against melanoma (A375) cells with IC50 of 48.14 µg mL−1, compared to RRME (IC50 = 131.24 µg mL−1). In conclusion, encapsulation through HPβCD inclusion complex formation improved its antibacterial and anticancer activities while preserving its antioxidant activity.

Encapsulation of Rhodiola rosea methanolic extract into HPβCD enhances its cytotoxicity against human melanoma (A375) cells and its antimicrobial activity against Pseudomonas putida, Escherichia coli, and Staphylococcus aureus.