Jaridon 6, a new diterpene from Rabdosia rubescens (Hemsl.) Hara, can display anti-gastric cancer resistance by inhibiting SIRT1 and inducing autophagy.

Tumor resistance is the main cause of treatment failure and is associated with many tumor factors. Jaridon 6, a new diterpene extracted from Rabdosia rubescens (Hemsl.) Hara, which has been previously extracted by our research team, has been tested having more obvious advantages in resistant tumor cells. However, its mechanism is unclear. In this study, we studied the effect and the specific mechanism of Jaridon 6 in resistant gastric cancer cells. Cytotoxicity test, colony test, western blotting, and nude test verified the anti-drug resistance ability of Jaridon 6 in the MGC803/PTX and MGC803/5-Fu cells. Jaridon 6 has shown obvious inhibitory effects in the sirtuin 1 (SIRT1) enzyme test. Transmission electron microscopy and immunofluorescence tests further proved the autophagic action of Jaridon 6. Jaridon 6 could inhibit the proliferation of the resistant gastric cancer cell in vivo and in vitro. Jaridon 6 inhibited SIRT1 enzyme and induced autophagy by inhibiting the phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) pathway. Thus, it may be considered for treating gastric cancer resistance by individual or combined administration, as an SIRT1 inhibitor and autophagy inducer.

Antioxidation and active constituents analysis of flower residue of Rosa damascena.

Objective: To make full usage of resource and turn waste into treasure, the chemical constituents and bioactivity were firstly investigated on Damask rose (Rosa damascena) flower residue (DRFR). Methods: DPPH and ABTS experiments were applied to assess the antioxidant activity of DRFR. Then, column chromatography was used to purify compounds from an antioxidation extract (DRFR-A), and the chemical structure was identified using NMR. The total phenolic acid content was measured by Folin-Ciocalteu colorimetric method, and the content of gallic acid of the indicator ingredient was detected by HPLC. Results: DRFR-A was found to show a high activity both on DPPH (IC50: 2.760 µg/mL) and ABTS (IC50: 2.258 µg/mL) compared to positive control VC. Ten compounds were isolated and identified as quercetin (1), kaempferol (2), gallic acid (3), protocatechuic acid (4), pyrogallic acid (5), 2-phenylethyl 3,4,5-trihydroxybenzoate (6), methyl gallate (7), p-hydroxybenzoic acid (8), p-hydroxyphenethyl alcohol (9) and astragalin (10) from DRFR-A. Among them, pyrogallic acid, 2-phenylethyl-3, 4, 5-trihydroxybenzoate, p-hydroxybenzoic acid and p-hydroxyphenethyl alcohol are obtained from the plant for the first time. The content of total phenolic acids and gallic acid, main ingredient in DRFR-A was determined as 63.73% and 24.67%, respectively. Conclusion: This study provides a reliable data and lays the foundation for the development and utilization of rose residue, and hence for the full utilization of rose resources.