Phytoconstituents with Radical Scavenging and Cytotoxic Activities from Diospyros shimbaensis

Abstract

As part of our search for natural products having antioxidant and anticancer properties, the phytochemical investigation of Diospyros shimbaensis (Ebenaceae), a plant belonging to a genus widely used in East African traditional medicine, was carried out. From its stem and root barks the new naphthoquinone 8,8′-oxo-biplumbagin (1) was isolated along with the known tetralones trans-isoshinanolone (2) and cis-isoshinanolone (3), and the naphthoquinones plumbagin (4) and 3,3′-biplumbagin (5). Compounds 2, 4, and 5 showed cytotoxicity (IC50 520–82.1 μM) against MDA-MB-231 breast cancer cells. Moderate to low cytotoxicity was observed for the hexane, dichloromethane, and methanol extracts of the root bark (IC50 16.1, 29.7 and > 100 μg/mL, respectively), and for the methanol extract of the stem bark (IC50 59.6 μg/mL). The radical scavenging activity of the isolated constituents (1–5) was evaluated on the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The applicability of the crude extracts and of the isolated constituents for controlling degenerative diseases is discussed.

Antiproliferation for Breast Cancer Cells by Ethyl Acetate Extract of Nepenthes thorellii x (ventricosa x maxima)

“…Plumbagin showed IC 50 values of 1.155 and 0.658 μg/mL to breast cancer MCF7 cells and noncancerous MCF-10A cells was 2.548 and 1.882 μg/mL at 24 and 48 h treatments, respectively [15]. In the current study, we found that the major bioactive components of EANT identified by HPLC fingerprinting method were isoplumbagin [21], cis -isoshinanolone [22], and quercetin 3- O -(6″- n -butyl β-D-glucuronide) [23] (Supplementary Figure S1). Isoplumbagin also isolated from the common leadwort ( Plumbago europaea ) and showed an anti-Candida effect [21], however, its anticancer effect was rarely reported.…”

“…Isoplumbagin also isolated from the common leadwort ( Plumbago europaea ) and showed an anti-Candida effect [21], however, its anticancer effect was rarely reported. cis -isoshinanolone also isolated from the plant ( Diospyros shimbaensis ) and showed antioxidant property without testing anticancer effect [22]. Quercetin 3- O -(6″- n -butyl β-D-glucuronide) also isolated from a slow-growing small leafless desert shrub ( Calligonum polygonoides ) and showed cytotoxic effect against liver cancer HepG2 and breast cancer MCF7 cells [23], that is, 60.46 and 61.4 μg/mL at 72 h sulphorhodamine-B assay.…”

Nepenthes Ethyl Acetate Extract Provides Oxidative Stress-Dependent Anti-Leukemia Effects

“…The bioactive compounds of EANT, including plumbagin, cis -isoshinanolone, and quercetin 3- O -(6″- n -butyl β-D-glucuronide), were reported previously by high-performance liquid chromatography (HPLC) analysis [ 12 ]. Except for cis -isoshinanolone [ 46 ], quercetin 3- O -(6″- n -butyl β-D-glucuronide) exhibits anticancer effects on liver and breast cancer cells [ 47 ], and plumbagin shows anticancer effects on several types of cancer cells [ 48 ]. For the ALL type of leukemia cells (MOLT-4), plumbagin shows an IC 50 value of 0.19 μg/mL for the 24 h CCK-8 assay, but it shows no cytotoxicity to normal peripheral blood mononuclear cells [ 49 ].…”

Research progress in pharmacological activities and structure-activity relationships of tetralone scaffolds as pharmacophore and fluorescent skeleton

“…From the stem and bark, two known tetralones 19 and 20 (Fig. 2) were isolated and identified from Diospyros shimbaensis [40].…”