Comparison of Antioxidant and Anticancer Properties of Soft Coral-Derived Sinularin and Dihydrosinularin

Abstract

Marine natural products are abundant resources for antioxidants, but the antioxidant property of the soft corals-derived sinularin and dihydrosinularin were unknown. This study aimed to assess antioxidant potential and antiproliferation effects of above compounds on cancer cells, and to investigate the possible relationships between them. Results show that sinularin and dihydrosinularin promptly reacted with 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS), and hydroxyl (•OH), demonstrating a general radical scavenger activity. Sinularin and dihydrosinularin also show an induction for Fe+3-reduction and Fe+2-chelating capacity which both strengthen their antioxidant activities. Importantly, sinularin shows higher antioxidant properties than dihydrosinularin. Moreover, 24 h ATP assays show that sinularin leads to higher antiproliferation of breast, lung, and liver cancer cells than dihydrosinularin. Therefore, the differential antioxidant properties of sinularin and dihydrosinularin may contribute to their differential anti-proliferation of different cancer cells.

Soft Coral-Derived Dihydrosinularin Exhibits Antiproliferative Effects Associated with Apoptosis and DNA Damage in Oral Cancer Cells

“…DHS exhibits antioxidant activity [26]. In general, antioxidants have dual functions for cell proliferation.…”

“…Some ROS-modulating agents were developed to exhibit antiproliferation effects for anticancer therapy and show little cytotoxicity to normal cells [36,37]. Since DHS has antioxidant abilities [26], DHS is a potential ROS-modulating agent. The principle is based on exogenous ROS that may exceed the ROS threshold of cancer cells with high levels of endogenous ROS.…”

“…Although sinularin and dihydrosinularin (DHS) were identified at the same time [20], most anticancer studies of Sinularia focus on sinularin [21][22][23][24][25]. The structural difference between sinularin and DHS is that sinularin provides an additional conjugated double bond compared to DHS [26]. Moreover, sinularin shows higher antioxidant abilities than DHS.…”

“…However, the anticancer effects of DHS have rarely been investigated to date. The cytotoxic effects of DHS have been reported in several cancer cell lines such as lung cancer, colon cancer, and leukemia [26,27]. Still, these studies only provided IC 50 values without a detailed investigation of the mechanism of its anticancer effect [26].…”

“…The cytotoxic effects of DHS have been reported in several cancer cell lines such as lung cancer, colon cancer, and leukemia [26,27]. Still, these studies only provided IC 50 values without a detailed investigation of the mechanism of its anticancer effect [26]. Additionally, the anticancer effect of this compound on oral cancer cells remains unclear.…”