In vitro anti-osteoporosis properties of diverse Korean Drynariae rhizoma phenolic extracts

Abstract

Drynariae rhizoma has been used to prevent bone loss that occurs with increasing age. However, the chemical compounds in extracts that act on bone metabolism in herbal medicine are poorly understood. This study aimed to investigate and compare the extraction efficacy of polyphenolic compounds, antioxidant activity, and in vitro anti-osteoporosis properties of water extract (DR-DW) and ethanol extract (DR-EtOH) from D. rhizoma. Total phenolics and flavonoids were better extracted with 70% EtOH, and this extraction method also resulted in higher antioxidant activity and in vitro anti-osteoporosis properties in these extracts. In particular, the contents of phloroglucinol, protocatechuic acid ethyl ester, 2-amino-3,4-dimethyl-benzoic acid, 3-(3,5-dimethyl-pyrazol-1-yl)-benzoic acid, chlorogenic acid, syringic acid, trans-ferulic acid, (-)-epigallocatechin, epigallocatechin gallate, quercetin dehydrate, luteolin and emodin in DR-EtOH were higher than those in DR-DW. These results indicated that DR-EtOH could be a good source of natural herbs with anti-osteoporosis properties.

Figure 1

The radical scavenging activity of water and ethanol extracts from Drynariae rhizoma. (A) Free radical scavenging activity; (B) Superoxide anion radical scavenging activity; (C) Hydroxyl radical scavenging activity.

Figure 2

Effects of water and ethanol extracts from Drynariae rhizoma on the proliferation of mouse osteoblastic cells. Cells were treated with vehicle (excipient) or various concentrations of D. rhizoma extracts for 48 h. Results are expressed as percentage of control (vehicle). Significant differences were compared with vehicle control (p < 0.05).

Figure 3

Morphological changes of mouse osteoblastic cells after treatment with various concentrations of DR-DW (A–D) and DR-EtOH (E–H) from Drynariae rhizoma. Scale bar = 20 μm.

Figure 4

Effects of water and ethanol extracts from Drynariae rhizoma on DNA synthesis of mouse osteoblastic cells. Cells were treated with vehicle or various concentrations of D. rhizoma extracts for 48 h. Results are expressed as percentage of control (vehicle). Significant differences were compared with vehicle control (p < 0.05).

Figure 5

Effects of water and ethanol extracts from Drynariae rhizoma on the alkaline phosphatase of mouse osteoblastic cells. Cells were treated with vehicle or various concentrations of D. rhizoma extracts for 96 h. Each point represents the Mean ± SD. Significant differences were compared with vehicle control (p < 0.05).