Effects of Bilobol from the Fruit Pulp of Ginkgo biloba on Cell Viability

Abstract

Cytotoxic activity profiling of the n-hexane extract from the fruit pulp of Ginkgo biloba L. (Gingkgoaceae) led to the purification of 8 compounds. HPLC based extract profiling identified a cytotoxic alkenylresorcinol. The extract was further separated by time-based fractionation in a gradient HPLC condition, and cytotoxicity of each fraction was evaluated using 293, B16F10, BJAB, and HCT116 cancer cells in vitro. Bilobol was isolated as an active constituent by semi-preparative HPLC and showed significant cytotoxic activities against the cancer cells in a dose-dependent manner at the concentrations of 15.0 ~ 50 μg/mL. The western blotting analysis showed that this compound increased expression of active caspase-3 and active caspase-8 in HCT116 human colon cancer cells, indicating that this compound causes apoptotic cell death in a dose-dependent manner. The results suggest that bilobol is the active component from fruit pulp of Ginkgo Biloba L. that can induce apoptotic cell death in various cancer cells.

Ginkgols and bilobols in Ginkgo biloba L. A review of their extraction and bioactivities

“…Regarding the extraction of bilobol, only a little research has been done (Kim & Yim, 2022; Tanaka et al, 2011; Zarnowska et al, 2000). In research by Zarnowska et al (2000), GB was extracted with acetone for 24 h, separated by filtration, and the acetone was eliminated in a rotary vacuum evaporator.…”

“…Concise synthesis of bilobol has been accomplished in 10 steps (yield = 51%) from 3,5‐ dihydroxybenzoic acid in research by Tanaka et al (2011). A 2 L of MeOH and GB (250 g) was thoroughly extracted three times in research by Kim and Yim (2022). First, the filtered MeOH layer was concentrated to yield an extract (100 g) that was then partitioned with 400 mL of n‐hexane and 300 mL of water to produce an n‐hexane extract (53.84 g) and was repeatedly separated by HPLC under 280 nm to get a bilobol (12.19 min, 31.0 mg) isolated as a yellow oil which 1 H NMR confirmed.…”

“…Few research on the use of bilobol as an anti‐cancer agent has been documented (Boyko & Brygadyrenko, 2021; Kim & Yim, 2022; Schulte et al, 2021; Tanaka et al, 2011; Xu et al, 2015). In research by Kim and Yim (2022), bilobol was separated by semi‐preparative HPLC, and the western blotting and cytotoxicity assay was used to describe apoptotic activities.…”

“…(a–h) CT26 cells were treated with media alone (a), dimethyl sulfoxide (DMSO) (b), or various amounts of bilobol (c–h) ([c] 3.125 μg/mL, [d] 6.25 μg/mL, [e] 12.5 μg/mL, [f] 25 μg/mL, [g] 50 μg/mL, [h] 100 μg/mL). (i) 293 cells, B16F10 cells, BJAB cells, or HCT116 cells were treated with designated quantities of bilobol for 24 h (Kim & Yim, 2022). …”

“…Few research on the use of bilobol as an anti‐cancer agent has been documented (Boyko & Brygadyrenko, 2021; Kim & Yim, 2022; Schulte et al, 2021; Tanaka et al, 2011; Xu et al, 2015). In research by Kim and Yim (2022), bilobol was separated by semi‐preparative HPLC, and the western blotting and cytotoxicity assay was used to describe apoptotic activities. To evaluate the cytotoxic effects of the isolated compound on tumor cells, we treated CT26 cells with different concentrations of bilobol (~3.125–100 μg/mL) for 24 h. Ginkgol demonstrated dose‐dependent cytotoxic impacts of the compound suppressing more than 50% of cell viability with the highest concentration compared to the control group (Figure 7a–h).…”